OA16950A - Carbon dioxide sequestration involving two-salt-based thermolytic processes. - Google Patents

Abstract

The present invention relates to an energy efficient carbon dioxide sequestration processes whereby calcium silicate minerals and CO2 are converted into limestone and sand using a twosalt thermolytic process that allows for the cycling of heat and chemicals from one step to another.

Description

This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 61/585,597, filed January 11,2012, hereby incorporated by reference in its entirety.

I. Field of the Invention

The présent invention generally relates to the field of removing carbon dioxide from a source, such as the waste stream (e.g. flue gas) of a power plant, whereby Group 2 silicate 10 minerais are converted into Group 2 chloride salts and S1O2, Group 2 chloride salts are converted into Group 2 hydroxide and/or Group 2 hydroxychloride salts. These in tum may be reacted with carbon dioxide to form Group 2 carbonate salts, optionally in the presence of catalysts. These steps may be combined to form a cycle in which carbon dioxide is sequestered in the form of carbonate salts and byproducts from one or more steps, such as 15 heat and chemicals, are re-used or recycled in one or more other steps.

II. Description of Related Art

Considérable domestic and international concem has been increasingly focused on the émission of CO2 into the air. In particular, attention has been focused on the effect of this gas on the rétention of solar heat in the atmosphère, producing the “greenhouse effect” Despite 20 some debate regaiding the magnitude of the effect al! would agréé there is a benefit to removing CO2 (and other chemicals) from point-émission sources, especially if the cost for doing so were suffîciently small.

Greenhouse gases are predominately made up of carbon dioxide and are produced by municipal power plants and large-scale industry in site-power-plants, though they are also 25 produced in any normal carbon combustion (such as automobiles, rain-forest clearing, simple buming, etc.). Though their most concentrated point-émissions occur at power-plants across the planet, making réduction or removal from those fixed sites an attractive point to effect a removal-technology. Because energy production is a primary cause of greenhouse gas émissions, methods such as reducing carbon intensity, improving efficicncy, and sequestering carbon from power-plant flue-gas by various means has been researched and studied intensively over the last thirty years.

Attempts at séquestration of carbon (in the initial form of gaseous CO2) hâve produced many varied techniques, which can be generally classified as géologie, terrestrial, 5 or océan Systems. An overview of such techniques is provided in the Proceedings of First National Conférence on Carbon Séquestration, (2001). To date, many if not ail of these techniques are too energy intensive and therefore not economically feasible, in many cases consuming more energy than the energy obtained by generating the carbon dioxide. Alternative processes that overcome one or more of these disadvantages would be 10 advantageous.

The referenced shortcomings are not intended to be exhaustive, but rather are among many that tend to impair the effectiveness of previously known techniques for removing carbon dioxide from waste streams; however, those mentioned here arc sufficient to demonstrate that the méthodologies appearing in the art hâve not been altogether satisfactory 15 and that a significant need exists for the techniques described and claimed in this disclosure.

SUMMARY OF THE INVENTION

Disclosed herein are methods and apparatuses for carbon dioxide séquestration, including removing carbon dioxide from waste streams.

In one aspect there are provided methods of sequestering carbon dioxide produced by 20 a source, comprising:

(a) reacting MgCh or a hydrate thereof with water in a first admixture under conditions suitable to form a first product mixture comprising a first step (a) product comprising Mg(OH)Cl and a second step (a) product comprising HCl;

(b) reacting some or ail of the Mg(OH)Cl from step (a) with a quantity of water and a quantity of MgClj in a second admixture under conditions suitable to form a second product mixture comprising a first step (b) product comprising Mg(OHh and a second step (b) product comprising MgCh. wherein the quantity of water is sufficient to provide a molar ratio of water to MgCh of greater than or equal to 6 to 1 in the second product mixture;

(c) admixing some or ail of the Mg(OHh from the first step (b) product with CaCh or a hydrate thereof and carbon dioxide produced by the source in a third admixture under conditions suitable to form a third product mixture comprising a first step (c) product

comprising MgClî or a hydrate thereof, a second step (c) product comprising CaCOj, and a third step (c) product comprising water; and (d) separating some or ail of the CaCOj from the third product mixture, whereby some or ail of the carbon dioxide is sequestered as CaCOj.

In certain embodiments, the MgCh of step (a) is a MgCh hydrate (e.g.,

MgCh-ôfHîO)). In some embodiments, the MgCh of step (a) is greater than 90% by weight MgCh-6(H2O). In still further embodiments, some or ail of the MgCh formed in step (b) and/or step (c) is the MgCh used in step (a). Thus, in certain embodiments, some or ail of the water in step (a) is présent in the form of a hydrate of the MgCh or is obtained from the water 10 of step (c) or step (b). In certain embodiments, some or ail of the water in step (a) is présent in the form of steam or supercritical water. In some embodiments some or ail of the hydrogen chloride of step (a) is admixed with water to form hydrochloric acid. In a further embodiment the first step (a) product comprises greater than 90% by weight Mg(OH)Cl. In certain embodiments step (a) occurs in one, two or three reactors.

In some embodiments, a defined quantity of water is maintained in the second product mixture of step (b). For example, in some embodiments, the molar ratio of water to MgCh in the second product mixture is between about 6 and about 10, between about 6 and 9, between about 6 and 8 , between about 6 and 7 or is about 6. In certain embodiments, a method comprises monitoring the concentration of MgCh in the second product mixture, the quantity 20 of water in the second product mixture or both. In still further embodiments, the amount MgCh and/or water in step (b) (or the flow rates of MgCh and/or water into the second admixture) is adjusted based on such monitoring.

In a further embodiment, a method comprises separating the step (b) products. For example, the Mg(OH)2 product of step (b) can be a solid and separating the step (b) products 25 can comprise separating some or ail of the solid Mg(OH)2 from the water and MgCh solution. Thus, in some embodiments, the MgCh product of step (b) is aqeous MgCh.

In yet a further embodiment step (b) comprises reacting some or ail of the Mg(OH)Cl from step (a) with MgCh and a quantity of water in a second admixture under conditions suitable to form a second product mixture comprising a first step (b) product comprising

Mg(OH>2 and a second step (b) product comprising MgCh, wherein the quantity of water is sufficient to provîde a molar ratio of water to Mg of greater than or equal to 6 to 1 in said second admixture. In some embodiments, the some or ail of the MgCl₂ for the reaction of step (b) is the MgCl₂ product of step (c).

In a further embodiment, step (c) further comprises admixing sodium hydroxide sait in the third admixture.

In still yet a further embodiment, a method comprises:

(e) admixing a calcium silicate minerai with HCl under conditions suitable to form a third product mixture comprising CaCl₂, water, and silicon dioxide.

For example, in some cases, some or ail of the HCl in step (e) is obtained from step (a). In certain embodiments, step (e) further comprises agitating the calcium silicate 10 minerai with HCl. In some embodiments, some or ail of the heat generated in step (e) is recovered. In certain embodiments, some or ail of the CaCl₂ of step (c) is the CaCl₂ of step (e). In further embodiments, a method comprises a séparation step, wherein the silicon dioxide is removed from the CaCl₂ formed in step (e). In yet further embodiments, some or ail of the water of step (a) and/or (b) is obtained from the water of step (e).

Certain aspects of the embodiments comprise use of a calcium silicate minerai, such as a calcium inosilicate. In some embodiments, the calcium silicate minerai comprises diopside (CaMgtSiîOeJ), tremolite Ca₂Mgs{[OHJSUOi ( }₂ or CaSiCh. In some embodiments, the calcium silicate further comprises iron (e.g., fayalite (Fe₂[SiO4])) and or manganèse silicates.

In some embodiments, the carbon dioxide is in the form of flue gas, wherein the flue gas further comprises N₂ and H₂O.

In some embodiments, suitable reacting conditions of step (a) comprise a température from about 200 °C to about 500 °C. In some embodiments, the température is from about 230 °C to about 260 °C. In some embodiments, the température is about 250 °C. In some 25 embodiments, the température is from about 200 °C to about 250 °C. In some embodiments, the température îs about 240 °C.

In some embodiments, suitable reacting conditions of step (b) comprise a température from about 140 °C to about 240 °C.

In some embodiments, suitable reacting conditions of step (c) comprise a température 30 from about 20 °C to about 100 °C. In some embodiments, the température is from about 25 °C to about 95 °C.

In some embodiments, suitable reacting conditions of step (e) comprise a température from about 50 °C to about 200 °C. In some embodiments, the température is from about 90 °C to about 150 °C.

In further aspect there are provided methods of sequestering carbon dioxide produced 5 by a source, comprising:

(a) reacting a first cation-based halide, sulfate or nitrate sait or hydrate thereof with water in a first admixture under conditions suitable to form a first product mixture comprising a first step (a) product comprising a first cation-based hydroxide sait, a first cation-based oxide sait and/or a first cation-based hydroxychloride sait and a second step (a) product comprising HCl, H2SO4 or HNO3;

(b) admixing some or ail of the first step (a) product with a second cation-based halide, sulfate or nitrate sait or hydrate thereof and carbon dioxide produced by the source in a second admixture under conditions suitable to form a second product mixture comprising a first step (b) product comprising a first cation-based halide, sulfate and/or nitrate sait or hydrate thereof, a second step (b) product comprising a second cation-based carbonate sait, and a third step (b) product comprising water, and (c) separating some or ail of the second cation-based carbonate sait from the second product mixture, whereby the carbon dioxide is sequestered into a minerai product form.

In some embodiments, the first cation-based halide sulfate or nitrate sait or hydrate thereof of step (a) is a first cation-based chloride sait or hydrate thereof, and the second step (a) product is HCl. In some embodiments, the first cation-based halide, sulfate, or nitrate sait or hydrate thereof of step (b) is a first cation-based chloride sait or hydrate thereof.

In some embodiments, the first cation-based chloride sait or hydrate thereof of step 25 (a) is MgCh- In some embodiments, the first cation-based chloride sait or hydrate thereof of step (a) is a hydrated form of MgClj. In some embodiments, the first cation-based chloride sait or hydrate thereof of step (a) is MgCh-ôHîO. In some embodiments, the first cationbased hydroxide sait of step (a) is Mg(OH)î. In some embodiments, the first cation-based hydroxychloride sait of step (a) is Mg(OH)Cl. In some embodiments, the first step (a) 30 product comprises predominantly Mg(OH)Cl. In some embodiments, the first step (a) product comprises greater than 90% by weight Mg(OH)Cl. In some embodiments, the first step (a) product is Mg(OH)Cl. In some embodiments, the first cation-based oxide sait of step (a) is MgO.

In some embodiments, the second cation-based halide, sulfate or nitrate sait or hydrate thereof of step (b) is a second cation-based chloride sait or hydrate thereof, for example, CaCI₂. In some embodiments, the first cation-based chloride sait of step (b) is MgCI₂. In some embodiments, the first cation-based chloride sait of step (b) is a hydrated form of MgCI₂. In some embodiments, the first cation-based chloride sait of step (b) is MgCl₂*6H₂O.

In some embodiments, some or ali of the water in step (a) is présent in the form of steam or supercritical water. In some embodiments, some or ail of the water of step (a) is obtained from the water of step (b). In some embodiments, step (b) further comprises admixing sodium hydroxide sait in the second admixture.

In some embodiments, the methods further comprise:

(d) admixing a Group 2 silicate minerai with HCl under conditions suitable to form a third product mixture comprising a Group 2 chloride sait, water, and silicon dioxide.

In some embodiments, some or ail of the HCl in step (d) is obtained from step (a). In 15 some embodiments, the methods of step (d) further comprises agitating the Group 2 silicate minerai with HCl. In some embodiments, some or ail of the heat generated in step (d) is recovered. In some embodiments, some or ail of the second cation-based chloride sait of step (b) is the Group 2 chloride sait of step (d). In some embodiments, the methods further comprise a séparation step, wherein the silicon dioxide is removed from the Group 2 chloride 20 sait formed in step (d). In some embodiments, some or ail of the water of step (a) îs obtained from the water of step (d).

In some embodiments, the Group 2 silicate minerai of step (d) comprises a Group 2 inosilicate. In some embodiments, the Group 2 silicate minerai of step (d) comprises CaSiOj. In some embodiments, the Group 2 silicate minerai of step (d) comprises MgSiOj. In some 25 embodiments, the Group 2 silicate minerai of step (d) comprises divine (Mg2[SiO41). In some embodiments, the Group 2 silicate minerai of step (d) comprises serpentine (MgetOHMSUOiol). In some embodiments, the Group 2 silicate minerai of step (d) comprises sepiolitc (Mg^fOHhSieOijJ-ôHzO), enstatite (Mg₂[Si₂O6]), diopside (CaMg[Si₂O61), and/or trcmolitc Ca₂Mgs{[OH]Si4On }₂. In some embodiments, the Group 2 30 silicate further comprises iron and or manganèse silicates. In some embodiments, the iron silicate is fayalitc (Fc₂[SiO4j).

In some embodiments, some or ail of the first cation-based chloride sait formed in step (b) is the first cation-based chloride sait used in step (a).

In some embodiments, the carbon dioxide is in the form of flue gas, wherein the flue gas further comprises N2 and H2O.

In some embodiments, suitable reacting conditions of step (a) comprise a température from about 200 °C to about 500 °C. In some embodiments, the température is from about 230 °C to about 260 °C. In some embodiments, the température is about 250 °C. In some embodiments, the température is from about 200 °C to about 250 °C. In some embodiments, the température is about 240 °C.

In some embodiments, suitable reacting conditions of step (a) comprise a température from about 50 °C to about 200 °C. In some embodiments, the température is from about 90 °C to about 260 °C. In some embodiments, the température is from about 90 °C to about 230 °C. In some embodiments, the température is about 130 °C.

In some embodiments, suitable reacting conditions of step (a) comprise a température from about 400 °C to about 550 °C. In some embodiments, the température is from about 450 °C to about 500 °C.

In some embodiments, suitable reacting conditions of step (a) comprise a température from about 20 °C to about 100 °C. In some embodiments, the température is from about 25 °C to about 95 °C.

In some embodiments, suitable reacting conditions of step (a) comprise a température from about 50 °C to about 200 °C. In some embodiments, the température is from about 90 °C to about 150 °C.

In another aspect, the présent invention provides methods of sequestering carbon dioxide produced by a source, comprising:

(a) admixing a magnésium chloride sait and water in a first admixture under conditions suitable to form (i) magnésium hydroxide, magnésium oxide and/or Mg(OH)Cl and (ii) hydrogen chloride;

(b) admixing (i) magnésium hydroxide, magnésium oxide and/or Mg(OH)Cl, (ii) CaCh and (iii) carbon dioxide produced by the source in a second admixture under conditions suitable to form (iv) calcium carbonate, (v) a magnésium chloride sait, and (vi) water; and (c) separating the calcium carbonate from the second admixture, whereby the carbon dioxide is sequestered into a minerai product form.

In some embodiments, some or ail of the hydrogen chloride of step (a) is admixed with water to form hydrochloric acid. In some embodiments, some or ail of the magnésium hydroxide, magnésium oxide and/or Mg(OH)C! of step (b)(i) is obtained from step (a)(i). In some embodiments, some of ail the water in step (a) is présent in the form of a hydrate of the magnésium chloride sait. In some embodiments, step (a) occurs in one, two or three reactors. In some embodiments, step (a) occurs in one reactor. In s'ome embodiments, the magnésium hydroxide, magnésium oxide and/or Mg(OH)C! of step (a)(i) is greater than 90% by weight Mg(OH)Cl. In some embodiments, the magnésium chloride sait is greater than 90% by weight MgC!r6(H₂O).

In some embodiments, the methods further comprise:

(d) admixing a Group 2 silicate minerai with hydrogen chloride under conditions suitable to form a Group 2 chloride sait, water, and silicon dioxide.

In some embodiments, some or ail of the hydrogen chloride in step (d) is obtained from step (a). In some embodiments, step (d) further comprises agitating the Group 2 silicate minerai with the hydrochloric acid. In some embodiments, some or ail of the magnésium chloride sait in step (a) is obtained from step (d). In some embodiments, the methods further comprise a séparation step, wherein the silicon dioxide is removed from the Group 2 chloride sait formed in step (d). In some embodiments, some or ail of the water of step (a) is obtained from the water of step (d). In some embodiments, the Group 2 silicate minerai of step (d) comprises a Group 2 inosilicate.

In some embodiments, the Group 2 silicate minera! of step (d) comprises CaSiCh. In some embodiments, the Group 2 silicate minera! of step (d) comprises MgSiOj. In some embodiments, the Group 2 silicate minera! of step(d) comprises divine. In some embodiments, the Group 2 silicate minera! of step(d) comprises serpentine. In some embodiments, the Group 2 silicate minerai of step (d) comprises sepiolite, enstatite, diopside, and/or tremolite. In some embodiments, the Group 2 silicate further comprises mineralized iron and or manganèse.

In some embodiments, step (b) further comprises admixing CaClj and water to the second admixture.

Other objects, features and advantages of the présent disclosure will become apparent from the following detailed description. It should be understood, however, that the detailed description and the spécifie examples, while indicating spécifie embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings form part of the présent spécification and are included to further demonstrate certain aspects of the présent disclosure. The invention may be better understood by référencé to one of these drawings in combination with the detailed description 5 of spécifie embodiments presented herein.

HG. 1 is block diagram of a system for a Group 2 hydroxide-based process to sequester CO2 as Group 2 carbonates according to some embodiments of the présent invention.

HG. 2 is block diagram of a system in which Mg²⁺ functions as a catalyst for the 10 séquestration of CO2 as calcium carbonate according to some embodiments of the présent invention.

HG. 3 is a simplified process flow diagram according to some embodiments of the processes provided herein. Shown is a Group-II hydroxide-based process, which sequesters CO₂ as limestone (composed Iargely of the minerai calcite, CaCOj). The term “road sait in 15 this figure refers to a Group II chloride, such as CaCh and/or MgCfc, either or both of which are optionally hydrated. In embodiments comprising MgCl₂, heat may be used to drive the reaction between road sait and water (including water of hydration) to form HCl and magnésium hydroxide, Mg(OH)2, and/or magnésium hydroxychloride, Mg(OH)Cl. In embodiments comprising CaCI₂, heat may be used to drive the reaction between road sait and 20 water to form calcium hydroxide and HCI. The HCl is reacted with, for example, calcium inosilicate rocks (optionally ground), to form additional road sait, e.g., CaCh, and sand (SiO₂).

HG. 4 is a simplified process-flow diagram corresponding to some embodiments of the présent invention. Silicate rocks may be used in some embodiments of the présent 25 invention to sequester CO2 as CaCOj. The term “road sait” in this figure refers to a Group II chloride, such as CaCh and/or MgCh, either or both of which are optionally hydrated. In the road sait boiler, heat may be used to drive the reaction between road sait, e.g., MgC12*6H2O, and water (including water of hydration) to form HCl and Group II hydroxides, oxides, and/or mixed hydroxide-chlorides, including, for example, magnésium hydroxide, Mg(OH)2, 30 and/or magnésium hydroxychloride, Mg(OH)CI. In embodiments comprising CaCh, heat may be used to drive the reaction between road sait and water to form calcium hydroxide and HCl. The HCl may be sold or reacted with silicate rocks, e.g., inosilicates, to form additional ίο road sait, e.g., CaCI₂, and sand (SiO₂). Ion exchange reaction between Mg²* and Ca²* may used, in some of these embodiments, to allow, for example, the cycling of Mg²* ions.

FIG. 5 is a process flow diagram showing parameters and results from a process simulation using Aspen Plus process software. In this embodiment, a 35% MgCl₂, 65% H₂O solution is heated to 536 °F (280 °C), then the stream leaves in the stream labeled H₂OMgOH,” which comprises a solution of MgCh and solid Mg(OH)₂. Typically, when Mg(OH)Cl dissolves in water it forms Mg(OHh (solid) and MgC!₂ (dissolved). Here the MgC12 is not used to absorb CO2 directly, rather it is recycled. The net reaction is the capture of CO2 from flue gas using inexpensive raw materials, CaCh and water, to form CaCC>3. Results from the simulation suggest that it îs efficient to recirculate a MgCl₂ stream and then to react it with H2O and heat to form Mg(OH)2. One or more of the aforementioned compounds then reacts with a CaC!₂/H₂O solution and CO₂ from the flue gas to ultimately form CaCOj, which is filtered out of the stream. The resulting MgCh formed is recycled to the first reactor to repeat the process.

FIG. 6 is a process flow diagram showing parameters and results from a process simulation using Aspen Plus process software. The net reaction is the capture of CO2 from flue gas using inexpensive raw materials, CaCl₂ and water, to form CaCCh. In this embodiment, the hexahydrate is dehydrated in three separate chambers and decomposed in the fourth chamber where the HCl that is formed from the décomposition is recirculated back to the third chamber to prevent any side reactions. Reactions occurrîng in these chambers include the following:

Chamber: MgC!₂-6H₂O-> MgCl₂-4H₂O + 2H₂O 100 °C

2^ Chamber: MgC!₂-4H₂O-> MgCl₂-2H2O + 2H₂O 125 °C

3”¹ Chamber: MgC!₂-2H₂O-> MgC!₂-H₂O + H₂O 160 °C (HCl vapor présent)

4^ώ Chamber: MgClrH^ -> Mg(OH)Cl + HC! 130 °C

HC! recirculates to the 3^rf chamber.

Chamber	Reaction	Model Temp.	Preferred Temp. Range	Notes
1“	MgC!2’6H2O—>MgC!2-4H2O+ 2H2O	100”C	90°C-120°C
2d	MgC!2-4H2O->MgC!2-2H2O + 2H2O	125”C	160°C-185qC
3”1	MgC!2-2H2O -> MgCl2H2O + H2O	160”C	190°C- 230°C	*

4a

MgCl2-H2O -4 Mg(OH)Cl + HCl

130°C

230°C-260°C

♦♦

* HCl Vapor Présent ** HCl Vapor Recirculates to the 3^ri Chamber

The first three reactions above may be characterized as déhydrations, while the fourth may be characterized as a décomposition. Results from this simulation, which is explained in greater detail in Example 2, indicate that at lower températures (130-250 °C) the décomposition of MgClî’ôHaO results in the formation of Mg(OH)Cl instead of MgO. The Mg(OH)Cl then reacts with H2O to form MgCh and Mg(OH>2, which then reacts with a saturated CaClz/HaO solution and CO2 from the flue gas to form CaCOj, which is filtered out of the stream. The resulting MgCh formed is recycled to the first reactor to begin the process again.

FIG. 7 is a process flow diagram showing parameters and results from a process simulation using Aspen Plus process software. The net reaction is the capture of CO2 from flue gas using inexpensive raw materials, CaCh and water, to form CaCOj. In this embodiment, the magnésium hexahydrate is dehydrated in two separate chambers and decomposed in a third chamber. Both déhydration and décomposition reactions occur in the third chamber. There is no recirculating HCl. Reactions occurring in these chambers include the following:

	1 Chamber: MgCl2-6H2O -4 MgCl2-4H2O + 2H2O 2D<1 Chamber: MgCl2-4H2O -4 MgCl2-2H2O + 2H2O 31 Chamber: MgClr2H2O -4 Mg(OH)Cl + HCl + H2O	100 °C 125 °C 130 °C
20	3ri Chamber: MgCl2-2H2O -4 MgCl2-H2O + H2O	130 °C

Chamber	Reaction	Model Temp.	Preferred Temp. Range	Notes
1«	MgC12*6H2O-4MgC12'4H2O+ 2H2O	100°C	90°C-120°C
2»<j	MgC12-4H2O-4MgClr2H2O + 2H2O	125°C	160°C-185°C
	MgC12-2H2O-4Mg(OH)Cl+HCl+ h2o	130°C	190°C-230°C	*
MgCl2-2H2O -4 MgC12H2O + H2O

* No recirculating HCl

The first, second and fourth reactions above may be characterized as déhydrations, while the third may be characterized as a décomposition. As in the embodiment of FIG. 6, the températures used in this embodiment resuit in the formation of Mg(OH)Cl from the

MgC12'6H2O rather than MgO. The Mg(OH)Cl then reacts with H2O to form MgCh and

Mg(OHh» which reacts with a saturated CaCfe/HzO solution and CO2 from the flue gas to form CaCO3, which is filtered out of the stream. The resulting MgCl₂ formed is recycled to the first reactor to begin the process again. Additional details regarding this simulation are provided in Example 3 below,

FIG. 8 is a process flow diagram showing parameters and results from a process simulation using Aspen Plus process software. The net reaction is the capture of CO₂ from flue gas using inexpensive raw materials, CaCt₂ and water, to form CaCC>3. Results from this simulation indicate that it is efficient to heat MgCl₂-6H₂O to form MgO. The MgO then reacts with H₂O to form Mg(OH)₂, which then reacts with a saturated CaCt₂/H₂O solution and CO₂ from the flue gas to form CaCO3, which is filtered out of the stream. The resulting MgCt₂ formed is recycled to the first reactor to begin the process again. In this embodiment, the magnésium hexahydrate is simultaneously dehydrated and decomposed in one chamber at 450 °C. This îs the modet termperature range. The preferred range in some emobodiments, is 450 °C - 500 °C. Thus the décomposition goes completely to MgO. The main reaction occurring in this chamber can be represented as follows:

MgCt₂‘6H₂O -> MgO + 5H₂O + 2HC1 450 °C

Additional details regarding this simulation are provided in Example 4 below.

FIG. 9 is a process flow diagram showing parameters and results from a process simulation using Aspen Plus process software similar to the embodiment of FIG. 8 except that the MgCl₂'6H₂O is decomposed into an intermediate compound, Mg(OH)Cl at a lower température of 250 °C in one chamber. The Mg(OH)CI is then dissolved in water to form MgCI₂ and Mg(OH)₂, which follows through with the same reaction with CaCl₂ and CO₂ to form CaCCh and MgCl₂. The main reaction occurring in this chamber can be represented as follows:

MgCl₂-6H₂O-» Mg(OH)Cl + HCl + 5H₂O 250 °C

The réaction was modeled at 250 °C. În some embodiments, the preferred range is from 230 °C to 260 °C. Additional details regarding this simulation are provided in Example 5 below.

FIG. 10 shows a graph of the mass percentage of a heated sample of MgCt₂*6H₂O. The sample’s initial mass was approximately 70 mg and set at 100%. During the experiment, the sample’s mass was measured while it was being thermally decomposed. The température was quickly ramped up to 150 °C, and then slowly increased by 0.5 °C per minute. At approximately 220 °C, the weight became constant, consistent with the formation of Mg(OH)CI.

FIG. 11 shows X-ray diffraction data corresponding to the product of Example 7.

FIG. 12 shows X-ray diffraction data corresponding to the product from the reaction using Mg(OH)î of Example 8.

FIG. 13 shows X-ray diffraction data corresponding to the product from the reaction using Mg(OH)Cl of Example 8.

FIG. 14 shows the effect of température and pressure on the décomposition of MgCl₂(H₂O).

FIG. 15 is a process flow diagram of an embodiment of the Ca/Mg process described herein.

FIG. 16 is a process flow diagram of a variant of the process, whereby only magnésium compounds are used. In this embodiment the Ca²⁺ - Mg²⁺ switching reaction does not occur.

FIG. 17 is a process flow diagram of a different variant of the process which is in between the previous two embodiments. Half of the Mg²⁺ is replaced by Ca²⁺, thereby making the resulting mineralized carbonate MgCa(CO₃)₂ or dolomite.

FIG. 18 - CaSiO₃-Mg(OH)CI Process, Cases 10 & 11. This figure shows a process flow diagram provîding parameters and results from a process simulation using Aspen Plus process software. The net reaction is the capture of CO₂ from flue gas using inexpensive raw materials, CaSiO₃, CO₂ and water, to form SiO₂ and CaCO₃. Results from this simulation indicate that it is efficient to use heat from the HCl reacting with CaSiO₃ and heat from the flue gas emitted by a natural gas or coal fired power plant to carry out the décomposition of MgCl₂-6H₂O to form Mg(OH)Cl. The Mg(OH)Cl then reacts with H₂O to form MgCl₂ and Mg(OH)î. which then reacts with a saturated CaCl₂/H₂O solution and CO₂ from the flue gas to form CaCOj, which is filtered out of the stream. The resulting MgCl₂ formed is recycled to the first reactor to begin the process again. In this embodiment, the magnésium chloride hexahydrate is dehydrated to magnésium chloride dihydrate MgCl₂>2H₂O in the first chamber using heat from the HCl and CaSiOj reaction and decomposed in a second chamber at 250°C using heat from the flue gas. Thus the décomposition goes partîally to Mg(OH)Cl. The main reactions occuning in this chamber can be represented as follows:

Reaction	ΔΗ** kj/mole	Reaction Temp. Range
MgCI2-6H2O -> Mg(OH)Cl + 5H2O + HCl	433	230 °C- 260 °C
2 HCl (g) + CaSiO3 —> CaCl2(aç) + H2O + S1O2I	-259	90 °C-150°C
2Mg(OH)Cl + CO2 + CaCl2 -> 2MgCl2 + CaCO3l + H2O	-266	25°C-95 °C

♦* Enthalpies are based on reaction températures, and températures of incomin g reactant and outgoing product streams. Additional details regarding this simulation are provided in Examples 10 and 11 below.

FIG. 19 - CaSiOj-MgO Process, Cases 12 & 13. This figure shows a process flow diagram providing parameters and results from a process simulation using Aspen Plus process software. The net réaction is the capture of CO₂ from flue gas using inexpensive raw materials, CaSiOj, CO₂ and water, to form SiO₂ and CaCO₃. Results from this simulation indicate that it is efficient to use heat from the HCl reacting with CaSiOj and heat from flue gas emitted by a naturel gas or coal fired power plant to carry out the décomposition of 10 MgCI₂*6H₂O to form MgO. The MgO then reacts with H₂O to form Mg(OH)₂, which then reacts with a saturated CaCl₂/H₂O solution and CO₂ from the flue gas to form CaCO₃, which is fiitered out of the stream. The resulting MgCl₂ formed is recycled to the first reactor to begin the process again. In this embodiment, the magnésium chloride hexahydrate is dehydrated to magnésium chloride dihydrate MgCl₂-2H₂O in the first chamber using heat 15 from the HCl and CaSiO₃ reaction and decomposed in a second chamber at 450°C using heat from the flue gas. Thus the décomposition goes completely to MgO. The main réactions occurring in this chamber can be represented as follows:

Reaction	ΔΗ kj/mole**	Reaction Temp. Range
MgCl2-6H2O -> MgO + 5H2O + 2HC!	560	450°C-500°C
2HCl(g) + CaSÎO3 CaCl2(aç) + H2O + SiO2l	-264	90°C-150°C
MgO + CO2 + CaCl2(iiç) —> MgCl2(aç) + CaCO3|	-133	25 °C-95 °C

** Enthalpies are based on reaction températures, and températures of incoming reactant and outgoing product streams. Additional details regarding this simulation are provided in

Examples 12 and 13 below.

FIG. 20 - MgSiO₃-Mg(OH)CI Process, Cases 14 & 15. This figure shows a process flow diagram providing parameters and results from a process simulation using Aspen Plus process software. The net reaction is the capture of CO₂ from flue gas using inexpensive raw materials, MgSiOj, CO2 and water, to form S1O2 and MgCCh. Results from this simulation indicate that it is efficient to use heat from the HCl reacting with MgSiOj and heat from the flue gas emitted by a natural gas or coal fïred power plant to carry out the décomposition of MgCfo'ÎHbO to form Mg(OH)Cl. The Mg(0H)Cl then reacts with H2O to form MgCh and Mg(OH)2, which then reacts with CO2 from the flue gas to form MgCOj, which is filtered out of the stream. The resulting MgCb formed is recycled to the first reactor to begin the process again. In this embodiment, the magnésium chloride remains in the dîhydrate form MgC12’2H2O due to the heat from the HCl and MgSiOj prior to décomposition at 250°C using heat from the flue gas. Thus the décomposition goes partially to Mg(OH)Cl. The main reactions occurring in this chamber can be represented as follows:

Reaction	ΔΗ kj/mole *♦	Reaction Temp. Ranges
MgC12-2H2O -> Mg(OH)CJ + H2O(g) + HCl(g)	139.8	230°C-260°C
2HCl(g) + MgSiOj -> MgCh + H2O + SiO2l	-282.8	90 °C-150°C
2Mg(0H)Cl + CO2 -> MgCl2 + MgCOjJ + H2O	-193.1	25 °C-95°C

** Enthalpies are based on reaction températures, and températures of incoming reactant and outgoing product streams. Additional details regarding this simulation are provided in Examples 14 and 15 below.

FIG. 21 - MgSiOj-MgO Process, Cases 16 & 17. This figure shows a process flow diagram providing parameters and results from a process simulation using Aspen Plus process software. The net réaction is the capture of CO2 from flue gas using inexpensive raw materials, MgSiOj, CO2 and water, to form S1O2 and MgCOj. Results from this simulation indicate that it is efficient to use heat from the HCl reacting with MgSiOj and heat from the flue gas emitted by a natural gas or coal fired power plant to carry out the décomposition of MgC12*2H2O to form MgO. The MgO then reacts with H2O to form Mg(0H)2, which then reacts with CO2 from the flue gas to form MgCOj, which is filtered out of the stream. In this embodiment, the magnésium chloride remains in the dihydrate form MgC12*2H2O due to the heat from the HCl and MgSiOj prior to décomposition at 450°C using heat from the flue gas. Thus the décomposition goes completely to MgO. The main reactions occurring in this chamber can be represented as follows:

Reaction	AH kj/mole **	Reaction Temp. Range
MgC12-2H2O -> MgO + H2O(g) + 2HCl(g)	232.9	450 °C-500°C
2HCl(g) + MgSiO3 -> MgChto) + H2O(g) + SiO2l	-293.5	90°C-150 °C
MgO + CO2 -> MgCOjl	-100	25 °C —95 °C

** Enthalpies are based on reaction températures, and températures of incoming reactant and outgoing product streams. Additional details regarding this simulation are provided in Examples 16 and 17 below.

FIG. 22 - Diopside*Mg(OH)C! Process, Cases 18 & 19. This figure shows a process flow diagram providing parameters and results from a process simulation using Aspen Plus process software. The net reaction is the capture of C0₂ from flue gas using inexpensive raw materials, diopside MgCafSiOjh» CO₂ and water, to form SiO₂ and dolomite MgCa(003)2- Results from this simulation indicate that it is efficient to use heat from the HCl reacting with MgCa(SiO₃)2 and heat from the flue gas emitted by a natural gas or coal 10 fired power plant to carry out the décomposition of MgCi₂*6H2O to form Mg(OH)Cl. The

Mg(OH)Ci then reacts with H2O to form MgCh and Mg(OH)2, which then reacts with a saturated CaC12/H2O solution and CO2 from the flue gas to form MgCa(CO₃>2 which is filtered out of the stream. The resulting MgCl₂ formed is recycled to the first reactor to begin the process again. In this embodiment, the magnésium chloride hexahydrate is dehydrated to 15 magnésium chloride dihydrate MgC12-2H2O in the first chamber using heat from the HCl and

CaSiOj reaction and decomposed to Mg(OH)Cl in a second chamber at 250°C using heat from the flue gas. The main reactions occurring in this chamber can be represented as follows:

Reaction	ΔΗ kj/mole**	Reaction Temp. Range
MgC12-6H2O -> Mg(OH)Ci + 5H2O(g) + HCl(g)	433	230 °C- 260 °C
2HCl(g) + MgCa(SiO3)2 -> CaChia?) + MgSiO3j + SiO2l + H2O	-235	90°C-150 °C
2HCl(g) + MgSiO3 -> MgCl2(o<7)+ SiO2l + H2O	-282.8	90°C-150°C
4Mg(OH)Cl + 2CO2 + CaCl2(a<7) -> MgCa(CO3)2l + 3MgCl2(a<7) + 2H2O	-442	25°C-95 °C

*♦ Enthalpies are based on reaction températures, and températures of incoming reactant and

outgoing product streams. Additional details regarding this simulation are provided in Examples 18 and 19 below.

FIG. 23 - Diopside-MgO Process, Cases 20 & 21. This figure shows a process flow diagram providing parameters and results from a process simulation using Aspen Plus process software. The net reaction is the capture of CO2 from flue gas using inexpensive raw materials, diopside MgCa(SiOj)2, CO2 and water, to form S1O2 and dolomite MgCaCCChh. Results from this simulation indicate that it is efficient to use heat from the HCl reacting with MgCa(SiOj)2 and heat from the flue gas emitted by a natural gas or coal fired power plant 10 and/or other heat source to carry out the décomposition of MgCh'ôfyO to form MgO. The MgO then reacts with H₂O to form Mg(OH)2, which then reacts with a saturated CaC^/HiO solution and CO2 from the flue gas to form MgCa(COj)2 which is filtered out of the stream. The resulting MgCk formed is recycled to the first reactor to begin the process again. In this embodiment, the magnésium chloride hexahydrate is dehydrated to magnésium chloride 15 dihydrate MgC12*2H2O in the first chamber using heat from the HCl and CaSiOj reaction and decomposed to MgO in a second chamber at 450°C using heat from the flue gas. The main reactions occurring in this chamber can be represented as follows:

Reaction	AH kj/mole**	Reaction Temp, Range
MgC12-6H2O -> MgO + 5H2O + 2HCI	560	450 °C- 500°C
2HCl(g) + MgCa(SiO3)2 CaCl2(g) + MgSiOjj + SiO2l + H2O	-240	90 °C- 150 °C
2HCl(a^) + MgSiOj -> MgCI2(ai) + S1O2I + H2O	-288	90 °C- 150 °C
2MgO + 2CO2 + CaChio?) MgCa(CO3)2|, + MgChio?)	-258	25 °C- 95 °C

♦* Enthalpies are based on reaction températures, and températures of incoming reactant and outgoing product streams. Additional details regarding this simulation are provided in 20 Examples 20 and 21 below.

FIG. 24 illustrâtes the percent CO2 captured for varying CO2 flue gas concentrations, varying températures, whether the fiue gas was originated from coal or natural gas, and also whether the process relied on full or partial décomposition. See Examples 10 through 13 of the CaSiO3-Mg(OH)Cl and CaSiOj-MgO processes.

FIG. 25 illustrâtes the percent CO₂ captured for varying CO₂ flue gas concentrations, varying températures, whether the flue gas was originated from coal or natural gas, and also whether the process relied on full or partial décomposition. See Examples 14 through 17 of the MgSiOj-Mg(OH)Cl and MgSiOj-MgO processes.

FIG. 26 illustrâtes the percent C0₂ captured for varying C0₂ flue gas concentrations, varying températures, whether the flue gas was originated from coal or natural gas, and also whether the process relied on full or partial décomposition. See Examples 18 through 21 of the Diopside - Mg(0H)Cl and Diopside - MgO processes.

FIG. 27 is a simplified process-flow diagram corresponding to some embodiments of the présent invention in which two different salts, e.g., Ca²⁺ and Mg²*, are used for décomposition and carbonation.

FIGS. 28-29 show graphs of the mass percentages of heated samples of MgCl₂-6H₂O. The initial masses of the samples were approximately 70 mg each and were each set at 100%. During the experiment, the masses of the samples were measured while they was being 15 thermally decomposed. The température was ramped up to 200 °C then further increased over the course of a 12 hour run. The identities of the decomposed materials can be confirmed by comparing against the theoretical plateaus provided. FIG. 28 is a superposition of two plots, the first one being the solid line, which is a plot of time (minutes) versus température (°C). The line illustrâtes the ramping of température over time; the second plot, 20 being the dashed line is a plot of weight % (100% = original weight of sample) versus time, which illustrâtes the réduction of the sample’s weight over time whether by déhydration or décomposition. FIG. 29 is also a superposition of two plots, the first (the solid line) is a plot of weight% versus température (°C), illustrating the sample’s weight decreasing as the température increases; the second plot (the dashed line) is a plot of the dérivative of the 25 weight% with respect to température (wt.%/°C) versus température °C. When this value is high it indicates a higher rate of weight loss for each change per degree. If this value is zéro, the sample’s weight remains the same although the température is increasing, indicating an absence of déhydration or décomposition. Note Figure 28 and 29 are of the same sample.

FIG. 30 - MgCl₂*6H₂O Décomposition at 500°C after One Hour. This graph shows the normal ized final and initial weights of four test runs of MgCl₂'6H₂O after heating at 500 °C for one hour. The consistent final weight confirms that MgO is made by décomposition at this température.

FIG. 31 - Three-Chamber Décomposition. This figure shows a process flow diagram providing parameters and results from a process simulation using Aspen Plus process software. In this embodiment, heat from cold flue gas (chamber 1), heat from minerai dissolution reactor (chamber 2), and external natural gas (chamber 3) are used as heat sources. This process flow diagram illustrâtes a three chamber process for the décomposition to Mg(OH)Cl. The first chamber is heated by 200 °C flue gas to provide some initial heat about -8.2% of the total required heat, the second chamber which relies on heat recovered from the minerai dissolution reactor to provide 83% of the needed heat for the décomposition of which 28% is from the hydrochloric acid/mineral silicate reaction and 55% is from the condensation and formation of hydrochloric acid, and finally the third chamber, which uses natural gas as an extemal source of the remaining heat which is 8.5% of the total heat. The CO2 is from a combined cycle power natural gas plant, so very little heat is available from the power plant to power the décomposition réaction.

FIG. 32 - Four-Chamber Décomposition. This figure shows a process flow diagram providing parameters and résulte from a process simulation using Aspen Plus process software. In this embodiment, heat from cold flue gas (chamber 1), heat from additional steam (chamber 2), heat from minerai dissolution reactor (chamber 3), and extemal natural gas (chamber 4) are used as heat sources. This process flow diagram illustrâtes a four chamber process for the décomposition to Mg(OH)Ct, the first chamber provides 200 °C flue gas to provide some initial heat about -8.2% of the total required heat, the second chamber provides heat in the form of extra steam which is 0.8% of the total heat needed, the third chamber which relies on heat recovered from the minerai dissolution reactor to provide 83% of the needed heat for the décomposition of which 28% is from the hydrochloric acid/mineral silicate reaction and 55% is from the condensation and formation of hydrochloric acid, and finally the fourth chamber, which uses natural gas as an extemal source of the remaining heat which is 8.0% of the total heat. The CO2 is from a combined cycle natural gas power plant, so very little heat is available from the power plant to power the décomposition reaction.

FIG. 33 - TwoChamber Décomposition. This figure shows a process flow diagram providing parameters and results from a process simulation using Aspen Plus process software. In this embodiment, heat from minerai dissolution reactor (chamber 1), and extemal natural gas (chamber 2) are used as heat sources. This process flow diagram illustrâtes a two chamber process for the décomposition to Mg(OH)Cl, the first chamber which relies on heat recovered from the minerai dissolution reactor to provide 87% of the needed heat for the décomposition of which 28% is from the hydrochloric acid/mineral silicate reaction and 59% is from the condensation and formation of hydrochloric acid, and the second chamber, which uses natural gas as an extemal source of the remaining heat which is 13% of the total heat. The CO₂ is from a combined cycle naturel gas power plant, so very little heat is available from the power plant to power the décomposition reaction.

FIG. 34 - Two-Chamber Décomposition. This figure shows a process flow diagram providing parameters and results from a process simulation using Aspen Plus process software. In this embodiment, heat from minerai dissolution reactor (chamber 1), and hot flue gas from open cycle naturel gas plant (chamber 2) are used as heat sources. This process flow diagram illustrâtes a two chamber process for the décomposition to Mg(OH)Cl, the first chamber which relies on heat recovered from the minerai dissolution reactor to provide 87% of the needed heat for the décomposition of which 28% is from the hydrochloric acid/mineral silicate reaction and 59% is from the condensation and formation of hydrochloric acid, and the second chamber, which uses hot flue gas as an external source of the remaining heat which is 13% of the total heat. The CO2 is from an open cycle naturel gas power plant, therefore substantiel heat is available from the power plant in the form of 600 °C flue gas to power the décomposition reaction.

FIG. 35 shows a schematic diagram of a Auger reactor which may be used for the sait décomposition reaction, including the décomposition of MgC12*6H2O to M(OH)C1 or MgO. Such reactors may comprises internai heating for efficient heat utilization, external insulation for efficient heat utilization, a screw mechanism for adéquate solid transport (when solid is présent), adéquate venting for HCl removal. Such a reactors has been used to préparé -1.8kg of -90% Mg(OH)Cl.

FIG. 36 shows the optimization index for two separate runs of making Mg(OH)Cl using an Auger reactor. The optimization index = % conversion x % efficiency.

FIG. 37 shows a process flow diagram of an Aspen mode! that simulâtes an CaSiOjMg(OH)Cl Process.

FIG. 38A-I shows a process flow diagram providing parameters and results from a process simulation using Aspen Plus process software. The net reaction is the capture of CO2 from flue gas using inexpensive raw materials, CaSiCh, CO2 and water, to form SiO₂ and CaCOj. Heat is used to carry out the décomposition of MgCiî'ôHîO to form Mg(OH)Cl. The Mg(OH)Cl then reacts with H2O to form MgCh and Mg(OH)2. The quantity of H2O is regulated to favor formation of solid Mg(OH)2 and aqueous MgC12 (which is recycled to the first reactor to begin the process again). The Mg(OH)2 then reacts with a saturated CaCl2/H2O solution and CO₂ from the flue gas to form CaCOj, which is filtered out of the stream. The resulting MgCl₂ formed is recycled to the first reactor to begin the process again.

A, is an overview diagram of the process. B-I, are overlapping enlargements of the overview diagram shown in A.

FIG. 39A-I shows a process flow diagram providing parameters and results from a process simulation using Aspen Plus process software. The net reaction is the capture of CO₂ from flue gas using inexpensive raw materials, CaSiOj, CO₂ and water, to form SiO₂ and CaCCh. Heat is used to carry out the décomposition of MgCl₂*6H₂O to form Mg(OH)Cl. The Mg(OH)Cl then reacts with H₂O to form MgCl₂ and Mg(OH)₂. The quantity of H₂O is regulated to favor formation of solid Mg(OH)₂ and aqueous MgCl₂ (which is recycled to the first reactor to begin the process again). The MgCOHh then reacts with a saturated CaCl₂/H₂O solution and CO₂ from the flue gas to form CaCOj, which is filtered out of the stream. The resulting MgCl₂ formed is recycled to the first reactor to begin the process again. A, is an overview diagram of the process. B-I, are overlapping enlargements of the overview diagram shown in A.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The présent invention relates to carbon dioxide séquestration, including energyefficient processes in which Group 2 chlorides are converted to Group 2 hydroxides and hydrogen chloride, which are then used to remove carbon dioxide from waste streams. In some embodiments, hydrogen chloride may be further reacted with Group 2 silicates to produce additional Group 2 chloride starting materials and silica.

In some embodiments, the methods and apparatuses of the invention comprise one or more of the following general components: (1) the conversion of Group 2 silicate minerais with hydrogen chloride into Group 2 chlorides and silicon dioxide, (2) conversion of Group 2 chlorides into Group 2 hydroxides and hydrogen chloride, (3) an aqueous decarbonation whereby gaseous CO₂ is absorbed into an aqueous caustic mixture comprising Group 2 hydroxides to form Group 2 carbonate and/or bicarbonate products and water, (4) a séparation process whereby the carbonate and/or bicarbonate products are separated from the liquid mixture, (5) the reuse or cycling of by-products, including energy, from one or more of the steps or process streams into another one or more steps or process streams. Each of these general components is explained in further detail below.

While many embodiments of the présent invention consume some energy to accomplish the absorption of CO₂ and other chemicals from flue-gas streams and to accomplish the other objectives of embodiments of the présent invention as described herein, one advantage of certain embodiments of the présent invention is that they provide ecological efficiencies that are superior to those of the prior art, while absorbing most or ail of the emitted CO2 from a given source, such as a power plant.

Another additional benefit of certain embodiments of the présent invention that distinguishes them from other CCh-removal processes is that in some market conditions, the products are worth considerably more than the reactants required or the net-power or plantdepreciation costs. In other words, certain embodiments are industrial methods of producing chloro-hydro-carbonate products at a profit, while accomplishing considérable removal of CO2 and incidental pollutants of concem.

I. Définitions

As used herein, the terms “carbonates” or carbonate products” are generally defined as minerai components containing the carbonate group, [CO3]^2-. Thus, the terms encompass both carbonate/bicarbonate mixtures and species containing solely the carbonate ion. The terms “bicarbonates” and “bicarbonate products are generally defined as minerai components containing the bicarbonate group, [HCOj]¹’ Thus, the terms encompass both carbonate/bicarbonate mixtures and species containing solely the bicarbonate ion.

As used herein “Ca/Mg” signifies either Ca alone, Mg alone or a mixture of both Ca and Mg. The ratio of Ca to Mg may range from 0:100 to 100:0, including, e.g., 1:99, 5:95, 10:90, 20:80, 30:70,40:60, 50:50, 60:40, 70:30, 80:20, 90:10, 95:5, and 99:1. The symbols “Ca/Mg”, “MgxCa(l-x)” and CaxMg(l-x) are synonymous. In contrast, “CaMg or MgCa refers to a 1:1 ratio of these two ions.

As used herein, the term “ecological efficiency is used synonymously with the term “thermodynamic efficiency” and is defined as the amount of CO2 sequestered by certain embodiments of the présent invention per energy consumed (represented by the équation “dCCh/âE”), appropriate units for this value are kWh/ton CO2. CO2 séquestration is denomînated in terms of percent of total plant CO2; energy consumption is similarly denominated in terms of total plant power consumption.

The terms “Group ΙΓ and Group 2” are used interchangeably.

“Hexahydrate” refers to MgCk'ôI^O.

In the formation of bicarbonates and carbonates using some embodiments of the présent invention, the term ion ratio” refers to the ratio of cations in the product divided by the number of carbons présent in that product. Hence, a product stream formed of calcium bicarbonate (CafHCOah) may be said to hâve an “ion ratio” of 0.5 (Ca/C), whereas a product stream formed of pure calcium carbonate (CaCCh) may be said to hâve an “ion ratio of 1.0 (Ca/C). By extension, an infinité number of continuous mixtures of carbonate and

bicarbonate of mono-, di- and tri valent cations may be said to hâve ion ratios varying between 0.5 and 3.0.

Based on the context, the abbreviation “MW” either means molecular weight or mégawatts.

The abbreviation “PFD” is process flow diagram.

The abbreviation “Q is heat (or heat duty). and heat is a type of energy. This does not include any other types of energy.

As used herein, the term “séquestration” îs used to refer generally to techniques or practices whose partial or whole effect is to remove COî from point émissions sources and to store that CO2 in some form so as to prevent its retum to the atmosphère. Use of this term does not exclude any form of the described embodiments from being considered séquestration techniques.

In the context of a chemical formula, the abbreviation W” refers to H2O.

The pyroxenes are a group of silicate minerais found in many igneous and metamorphic rocks. They share a common structure consisting of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic Systems. Pyroxenes hâve the general formula XYfSirAlhOô. where X represents calcium, sodium, iron (Π) and 20 magnésium and more rare 1 y zinc, manganèse and lithium and Y represents ions of smaller size, such as chromium, aluminium, iron(III), magnésium, manganèse, scandium, titanium, vanadium and even iron (II).

In addition, atoms making up the compounds of the présent invention are intended to include ail isotopic forms of such atoms. Isotopes, as used herein, include those atoms 25 having the same atomic number but different mass numbers. By way of general example and without limitation, isotopes of hydrogen include tritium and deuterium, and isotopes of carbon include ¹³C and ^t4C.

The use of the word “a or “an, when used in conjunction with the term “comprising in the daims and/or the spécification may mean one, but it is also consistent with the meaning of one or more,” at least one, and one or more than one.

Throughout this application, the term about is used to indicate that a value includes the inhérent variation of error for the device, the method being employed to détermine the value, or the variation that exists among the study subjects.

The tenus “comprise,” “hâve and “include are open-ended lînkîng verbs. Any forms or tenses of one or more of these verbs, such as “comprises,” “comprising,” “has,” “having,” “includes” and “including,” are also open-ended. For ex ample, any method that “comprises, “has” or “includes” one or more steps is not limited to possessing only those one or more steps and also covers other unlisted steps.

The term “effective, as that term is used in the spécification and/or claims, means adéquate to accomplish a desired, expected, or intended resuit.

The above définitions supersede any conflicting définition in any of the reference that is incorporated by reference herein. The fact that certain ternis are defined, however, should not be considered as indicative that any term that is undefincd is indefinite. Rather, ail terme used are believed to describe the invention in ternis such that onc of ordinary skill can appreciate the scope and practice the présent invention.

II. Séquestration of Carbon Dloxlde Using Salts of Group II Metals

FIG. 1 depicts a simplified process-flow diagram illustrating general, exemplary embodiments of the apparatuses and methods of the présent disclosure. This diagram is offered for illustrative purposes only, and thus it merely depicts spécifie embodiments of the présent invention and is not intended to limit the scope of the claims in any way.

In the embodiment shown in FIG. 1, reactor 10 (e.g., a road sait boiler) uses power, such as external power and/or recaptured power (e.g., heat from hot flue gas or an external source of heat such as solar concentration or combustion), to drive a reaction represented by équation 1.

(Ca/MgJCIj + 2 H₂O —> (Ca/Mg)(OH>2 + 2 HCl (1)

The water used in this reaction may be in the form of liquid, steam, a crystalline hydrate, e.g., MgClî-ôHîO, CaClr2H;iO, or it may be supercritical. In some embodiments, the reaction uses MgCl₂ to form MgfOHh and/or Mg(OH)Cl (see, e.g., FIG. 2). In some embodiments, the reaction uses CaCh to form Ca(OHh. Some or ail of the Group 2 hydroxide or hydroxychloride (not shown) from équation 1 may be delivered to reactor 20. In some embodiments, some or ail of the Group 2 hydroxide and/or Group 2 hydroxychloride is delivered to reactor 20 as an aqueous solution. In some embodiments, some or ail of the Group 2 hydroxide is delivered to reactor 20 in an aqueous suspension. In some embodiments, some or ail of the Group 2 hydroxide is delivered to reactor 20 as a solid. In some embodiments, some or ail of the hydrogen chloride (e.g., in the form of vapor or in the form of hydrochloric acid) may be delivered to reactor 30 (e.g., a rock melter). In some embodiments, the resulting Group 2 hydroxides are further heated to remove water and form corresponding Group 2 oxides. In some variants, some or ail of these Group 2 oxides may then be delivered to reactor 20.

Carbon dioxide from a source, e.g., flue-gas, enters the process at reactor 20 (e.g., a fluidized bed reactor, a spray-tower decarbonator or a decarbonation bubbler), potentially after initial 1 y exchanging waste-heat with a waste-heat/DC génération system. In some embodiments the température of the flue gas is at least 125 °C. The Group 2 hydroxide, some or ail of which may be obtained from reactor 10, reacts with carbon dioxide in reactor 20 according to the reaction represented b y équation 2.

(Ca/Mg)(OH>2 + CO₂ -> (Ca/Mg)CO₃ + H₂O (2)

The water produced from this reaction may be delivered back to reactor 10. The Group 2 carbonate is typically separated from the reaction mixture. Group 2 carbonates hâve a very low K_sp (solubility product constant). So they be separated as solids from other, more soluble compounds that can be kept in solution. In some embodiments, the reaction proceeds through Group 2 bicarbonate salts. In some embodiments, Group 2 bicarbonate salts are generated and optionally then separated from the reaction mixture. In some embodiments, Group 2 oxides, optionally together with or separately from the Group 2 hydroxides, are reacted with carbon dioxide to also form Group 2 carbonate salts. In some embodiments, the flue gas, from which CO₂ and/or other pollutants hâve been removed, is released to the air.

Group 2 silicates (e.g., CaSÎOj, MgSiOj, MgOFeO-SiO₂, etc.) enter the process at reactor 30 (e.g., a rock melter or a minerai dissociation reactor). In some embodiments, these Group 2 silicates are ground in a prior step. In some embodiments, the Group 2 silicates are inosilicates. These minerais may be reacted with hydrochloric acid, either as a gas or in the form of hydrochloric acid, some or ail of which may be obtained from reactor 10, to form the corresponding Group 2 métal chlorides (CaCl₂ and/or MgCl₂), water and sand (SiO₂). The reaction can be represented by équation 3.

HCl + (Ca/Mg)SiO₃ -> (Ca/Mg)Cl₂ + H₂O + SiO₂ (3)

Some or ail of the water produced from this reaction may be delivered to reactor 10. Some or ail of the Group 2 chlorides from équation 3 may be delivered to reactor 20. In some embodiments, some or ail of the Group 2 chloride is delivered to reactor 20 as an aqueous solution. In some embodiments, some or ail of the Group 2 chloride is delivered to reactor 20 in an aqueous suspension. In some embodiments, some or ail of the Group 2 chloride is delivered to reactor 20 as a solid.

The net reaction capturing the summation of équations 1-3 is shown here as équation

4:

CO₂ + (Ca/Mg)SiO₃ -> (Ca/Mg)CO₃ + SiO₂ (4)

In another embodiment, the resulting Mg^Caq-^COa séquestrant is reacted with HCl in a manner to regenerate and concentrate the CO₂. The Ca/MgCI₂ thus formed is retumed to the décomposition reactor to produce CO₂ absorbing hydroxides or hydroxyhalides.

Through the process shown in FIG. 1 and described herein, Group 2 carbonates are generated as end-sequestrant material from the captured CO₂. Some or ail of the water, hydrogen chloride and/or reaction energy may be cycled. In some embodiments, only some or none of these are cycled. In some embodiments, the water, hydrogen chloride and reaction energy made be used for other purposes.

In some embodiments, and depending on the concentration of CO₂ in the flue gas stream of a given plant, the methods disclosed herein may be used to capture 33-66% of the plant’s COi using heat-only as the driver (no electrical penalty). In some embodiments, the efficiencies of the methods disclosed herein improve with lower C0₂-concentrations, and increase with higher (unscrubbed) flue-gas températures. For example, at 320 °C and 7% CO₂ concentration, 33% of flue-gas CO₂ can be mineralized from waste-heat alone. In other embodiments, e.g., at the exit températures of natural gas turbines approximately 100% mineralization can be achieved.

These methods and devices can be further modified, e.g., with modular components, optimized and sealed up using the principles and techniques of chemistry, chemical engineering, and/or materials science as applied by a person skilled in the art. Such principles and techniques are taught, for example, in U.S. Patent 7,727,374, U.S. Patent Application Publications 2006/0185985 and 2009/0127127, U.S. Patent Application No. 11/233,509, filed September 22, 2005, U.S. Provisional Patent Application No. 60/718,906, filed September 20,2005; U.S. Provisional Patent Application No. 60/642,698, filed January 10, 2005; U.S. Provisional Patent Application No. 60/612,355, filed September 23, 2004, U.S. Patent Application No. 12/235,482, filed September 22, 2008, U.S. Provisional Application No. 60/973,948, filed September 20, 2007, U.S. Provisional Application No. 61/032,802, filed February 29, 2008, U.S. Provisional Application No. 61/033,298, filed March 3, 2008, U.S. Provisional Application No. 61/288,242, filed January 20, 2010, U.S. Provisional Application No. 61/362,607, filed July 8,2010, and International Application No.

PCT/US08/77122, filed September 19,2008. The entire text of each of the above-referenced disclosures (including any appendices) is specifically incorporated by reference herein.

The above exaniples were included to demonstrate particular embodiments of the invention. However, those of skill in the art should, in light of the présent disclosure, appreciate that many changes can be made in the spécifie embodiments which are disclosed and still obtain a like or similar resuit without departing from the spirit and scope of the invention.

ΙΠ. Séquestration of Carbon Dioxide Using Mg²* as Catalyst

FIG. 2 depicts a simplified process-flow diagram illustrating general, exemplary embodiments of the apparatuses and methods of the présent disclosure. This diagram is offered for illustrative purposes only, and thus it merely depicts spécifie embodiments of the présent invention and is not intended to limit the scope of the claims in any way.

In the embodiment shown in FIG. 2, reactor 100 uses power, such as external power and/or recaptured power (e.g., heat from hot flue gas), to drive a décomposition -type reaction represented by équation 5.

MgCl₂-x(H₂O) + yH₂O->

z'[Mg(OH)₂] + z[MgO] + z'[MgCl(OH)] + (2z' + 2z + z')[HCl] (5)

The water used in this reaction may be in the form of a hydrate of magnésium chloride, liquid, steam and/or it may be supercritical. In some embodiments, the réaction may occur in one, two, three or more reactors. In some embodiments, the réaction may occur as a batch, semî-batch of continuous process. In some embodiments, some or ail of the magnésium sait product may be delivered to reactor 200. In some embodiments, some or ail of the magnésium sait product is delivered to reactor 200 as an aqueous solution. In some embodiments, some or ail of the magnésium sait product is delivered to reactor 200 in an aqueous suspension. In some embodiments, some or ail of the magnésium sait product is delivered to reactor 200 as a solid. In some embodiments, some or ail of the hydrogen chloride (e.g., in the form of vapor or in the form of hydrochloric acid) may be delivered to reactor 300 (e.g., a rock melter). In some embodiments, the Mg(OH)₂ is further heated to remove water and form MgO. In some embodiments, the MgCl(OH) is further heated to remove HCl and form MgO. In some variants, one or more of MgiOHh, MgCl(OH) and MgO may then be delivered to reactor 200.

Carbon dioxide from a source, e.g., flue-gas, enters the process at reactor 200 (e.g., a fluidized bed reactor, a spray-tower decarbonator or a decarbonation bubbler), potentially after inîtially exchanging waste-heat with a waste-heat/DC génération system. In some embodiments the température of the flue gas is at least 125 °C. Admixed with the carbon dioxide is the magnésium sait product from reactor 100 and CaCI₂ (e.g., rock sait). The carbon dioxide reacts with the magnésium sait product and CaCl₂ in reactor 200 according to the reaction represented by équation 6.

CO₂ + CaCl₂ + z'IMgiOHh] + z[MgO] + z'[MgCl(OH)] ->

(z' + z + z')MgCl₂ + (z* + ½z')H₂O + CaCO₃ (6)

In some embodiments, the water produced from this reaction may be delivered back to reactor 100. The calcium carbonate product (e.g., limestone, calcite) is typicaliy separated (e.g., through précipitation) from the reaction mixture. In some embodiments, the reaction proceeds through magnésium carbonate and bicarbonate salts. In some embodiments, the reaction proceeds through calcium bicarbonate salts. In some embodiments, various Group 2 bicarbonate salts are generated and optionally then separated from the reaction mixture. In some embodiments, the flue gas, from which CO₂ and/or other pollutants hâve been removed, is released to the air, optionally after one or more further purification and/or treatment steps. In some embodiments, the MgCl₂ product, optionally hydrated, is retumed to reactor 100. In some embodiments, the MgCl₂ product is subjected to one or more isolation, purification · and/or hydration steps before being retumed to reactor 100.

Calcium silicate (e.g„ 3CaO-SiO₂, CaaSiOj-, 2030-51(¾. Ca₂SiO4; 3CaO-2SiO₂, CajShOî and CaO-SiO₂, CaSiOj enters the process at reactor 300 (e.g., a rock melter). In some embodiments, these Group 2 silicates are ground in a prior step. In some embodiments, the Group 2 silicates are inosilicates. In the embodiment of FIG. 2, the inosilicate is CaSiOj (e.g., wollastonite, which may itself, in some embodiments, contain small amounts of iron, magnésium and/or manganèse substitutîng for iron). The CaSiOj is reacted with hydrogen chloride, either gas or in the form of hydrochloric acid, some or ail of which may be obtained from reactor 100, to form CaCl₂, water and sand (SiCb). The reaction can be represented by équation 7.

HCl + (Ca/Mg)SiOj -> (Ca/Mg)Cl₂ + H₂O + SiO₂ (7)

Reaction	AH kj/mole**	Reaction Temp. Range
2 HCl(g) + CaSiOj -> CaCl2 + H2O + SiO2	-254	90eC-150’C
2 HCl(g) + MgSiOj -> MgCl2(a<7) + H2O + SiO2	-288	90 °C-150 °C

** Enthalpies are based on reaction températures, and températures of incoming reaétant and outgoing product streams. Some or ail of the water produced from this reaction may be delivered to reactor 100. Some or ail of the CaCh from équation 7 may be delivered to reactor 200. In some embodiments, some or ail of the CaCh is delivered to reactor 200 as an aqueous solution. In some embodiments, some or ail of the CaCh is delivered to reactor 200 in an aqueous suspension. In some embodiments, some or ail of the CaCh is delivered to reactor 200 as a solid.

The net reaction capturing the summation of équations 5-7 is shown here as équation 8:

CO2 + CaSiOj —> CaCOj + S1O2 (8)

Reaction	ΔΗ kj/mo!e**	AGkJ/mole**
CO2 + CaSiOj —> CaCOj + S1O2	-89	-39

** Measured at standard température and pressure (STP). Through the process shown in FIG. 2 and described herein, calcium carbonates are generated as end-sequestrant material from CO2 and calcium inosilicate. Some or ail of the various magnésium salts, water, hydrogen chloride and reaction energy may be cycled. In some embodiments, only some or none of these are cycled. In some embodiments, the water, hydrogen chloride and/or reaction energy made be used for other purposes.

These methods and devices can be further modified, optimized and sealed up using the principles and techniques of chemistry, chemical engineering, and/or materials science as applied by a person skilled in the art. Such principles and techniques are taught, for example, in U.S. Patent 7,727,374, U.S. Patent Application Publications 2006/0185985 and 2009/0127127, U.S. Patent Application No. 11/233,509, filed September 22, 2005, U.S. Provisional Patent Application No. 60/718,906, filed September 20, 2005; U.S. Provisîonal Patent Application No. 60/642,698, filed January 10, 2005; U.S. Provisional Patent Application No. 60/612,355, filed September 23, 2004, U.S. Patent Application No. 12/235,482, filed September 22, 2008, U.S. Provisional Application No. 60/973,948, filed September 20, 2007, U.S. Provisional Application No. 61/032,802, filed February 29, 2008, U.S. Provisional Application No. 61/033,298, filed March 3, 2008, U.S. Provisional Application No. 61/288,242, filed January 20, 2010, U.S. Provisional Application No. 61/362,607, filed July 8, 2010, and International Application No. PCT/US08/77122, filed

September 19, 2008. The entire text of each of the above-referenced disclosures (including any appendices) is specifïcally incorporated by reference herein.

The above examples were included to demonstrate particular embodiments of the invention. However, those of skill in the art should, in light of the présent disclosure, appreciate that many changes can be made in the spécifie embodiments which are disclosed and still obtain a like or similar resuit without departing from the spirit and scope of the invention.

IV. Conversion of Group 2 Chlorides into Group 2 Hydroxides or Group Π Hydroxy Chlorides

Disclosed herein are processes that react a Group 2 chloride, e.g., CaCl₂ or MgCl₂, with water to form a Group 2 hydroxide, a Group 2 oxide, and/or a mixed sait such as a Group 2 hydroxide chloride. Such reactions are typically referred to as décompositions. In some embodiments, the water may be in the form of liquid, steam, from a hydrate of the Group 2 chloride, and/or it may be supercritical. The steam may corne from a heat exchanger whereby heat from an immenseiy combustible reaction, i.e. natural gas and oxygen or hydrogen and chlorine heats a stream of water. In some embodiments, steam may also be generated through the use of plant or factory waste heat. In some embodiments, the chloride sait, anhydrous or hydrated, is also heated.

In the case of Mg²⁺ and Ca²⁺, the reactions may be represented by équations 9 and 10, respectively:

MgCl₂ + 2 H₂O -> Mg(OHh + 2 HCl(g) ΔΗ = 263 kJ/mole** (9)

CaCl₂ + 2 H₂O CaiOHh + 2 HCl(g) ΔΗ = 284 kJ/mole** (10) ♦•Measured at 100 °C. The reactions are endothermie meaning energy, e.g., heat has to be applied to make these reactions occur. Such energy may be obtained from the waste-heat generated from one or more of the exothermic process steps disclosed herein. The above reactions may occur according to one of more of the following steps:

CaCl₂ + (x + y + z) H₂O -> Ca²⁺xH₂O + ClyH₂O + ClzH₂O (11)

Ca⁺²xH₂O + CfyHzO + CizH₂O [Ca²⁺-(x-l)(H2O)OH~]⁺ + CE-(yH2O) + CF(z-l)H₂O + H₃O⁺ (12) [Ca²⁺(x-l)(H2O)OH]⁺ + Cr(yH2O) + Cl*(z-1)H₂O + H₃O⁺ ->

[Ca²⁺(x-l)(H2O)OIT]⁺ + Cr-(yH2O)“ + zH₂O + HCl(g)î(13) [Ca²⁺(x-l)(H2O)OHl⁺ + CP(yH2O) ->

[Ca²⁺-(x-2)(H₂O) (OH)₂] + Cr-(y-l)H₂O + H₃O⁺(14) [Ca²⁺(x-2)(H₂O) (OH)il + Cr(y-1)H₂O + H₃O⁺

CaCOHhl + (x-2)H₂O + yH₂O + HClf(15)

The reaction enthalpy (ΔΗ) for CaCl₂ + 2 H₂O -> Ca(OH)₂ + 2 HCl(g) is 284 kJ/mole at

100 °C. In some variants, the sait MgCl₂-6H₂O, magnésium hexahydrate, is used. Since water is incorporated into the molecular structure of the sait, direct heating without any 10 additional steam or water may be used to înitiate the décomposition. Typical reactions températures for the following reactions are shown here:

From 95-110 °C:

MgCl2-6H2O -> MgCl2-4H2O + 2 H2O	(16)
MgCl2-4H2O -> MgCl2-2H2O + 2 H2O	(17)
From 135-180 °C:
MgCl2-4H2O -> Mg(OH)Cl + HCl + 3 H2O	(18)
MgCl2-2H2O -> MgCl2H2O + H2O	(19)
From 185-230 °C:
MgCl2-2H2O -> Mg(OH)Cl + HCl +H2O	(20)
From >230 °C:
MgCl2-H2O MgCl2 + H2O	(21)
MgCl2-H2O -> Mg(OH)Cl + HCl	(22)

Mg(OH)Cl —> MgO + HCl (23)

Reaction	Referenced Temp. Range	ΔΗ kj/mole**	Temp. Reaction
MgCl2-6H2O MgCl2-4H2O + 2 H^fg)	95 °C- 110 °C	115.7	100°C
MgCl2-4H2O MgCl2-2H2O + 2 H2O(g)	95 °C- 110°C	134.4	100°C
MgCl2-4H2O Mg(OH)Cl + HCI(g) + 3 H2O(g)	135 °C- 180 °C	275	160°C
MgCl2-2H2O MgCl2-H2O + H2O(g)	135 °C- 180 °C	70.1	160°C
MgCl2-2H2O Mg(0H)Cl + HCl (g) +H2O(g)	185 “C- 230 °C	141	210°C
MgCl2H2O MgCl2 + H2O(g)	>230 °C	76.6	240°C
MgCl2H2O Mg(OH)Cl + HCl(g)	>230 °C	70.9	240°C
Mg(OH)Cl MgO + HClCg)	>230 °C	99.2	450°C

** ΔΗ values were caiculated at the température of reaction (column ‘Temp. Reaction). See the chemical reference Kirk Othmer 4ed. Vol. 15 p. 343 1998 John Wiley and Sons, which is incorporated herein by reference. See example 1, below, providing results from a simulation that demonstrating the ability to capture C0₂ from flue gas using an inexpensive 5 raw material, CaCl₂, to form CaCOj. See also Energy Requirements and Equilibrium in the déhydration, hydrolysis and décomposition of Magnésium Chloride - K.K. Kelley, Bureau of Mines 1941 and Kinetic Analysis of Thermal Déhydration and Hydrolysis of MgCh.ôH^ by DTA and TG - Y. Kirsh, S. Yariv and S. Shoval - Journal of Thermal Analysis, Vol. 32 (1987), both of which are incorporated herein by reference in their entireties.

In certain aspects, Mg(OH)₂ can be more efficiently generated from MgCl₂ (via

Mg(OH)Cl) by adjusting the proportion of MgCh and water in the presence of Mg(OH)Cl. In order to optimize production of Mg(OHh, the amount of water in the chamber is adjusted to favor Mg(OHh précipitation, while preventing formation of MgCl₂-6(H₂O) hydrates. Specifically, the amount of water in a Mg(OH)CI solution is maintained at a water to MgCl₂ molar ratio of greater than or equal to 6, such as a ratio of of between about 6 and 7. Under these conditions Mg(OH>2, which is virtually insoluble, whereas the magnésium chloride remains in an aqueous solution. See, for example page 52 of de Bakker 2011, the entire disclosure of which is incorporated herein by reference.

Thus, to reach a product mixture of MgCl₂-6H₂O and Mg(0Hh Mg(0H)Cl is reacted with an aqueous MgCl₂ solution, such as that from the bubble column. That reaction would be:

CaCl₂(aq) + CO₂ + Mg(OH)₂ => MgCl₂(aq) + CaCO₃H₂O

MgCl₂(aq) - MgCl₂-13-16H₂O(liquid)

Boiling the mixture MgCl₂-13-16H₂O(!iquid) + ΔΗ => MgCI₂-6H2O(solid) + 79H₂O(gas)f would require signifîcant energy usage. Thus, a solution more dilute than MgCl₂-6H2Û shall cause the disproportionation of Mg(OH)Cl, a solution of MgCI₂.xH2O(liquid) where x > 12 should also be able to cause the disproportionation of Mg(OH)Cl. The équation is written as follows:

Mg(0H)Cl + ½ MgCl₂-13-16H₂O(!iquid) => ¼ Mg(OH>2 + MgC!₂-6.5-8H₂O

Such as: Mg(OH)Cl + ½ MgCl₂-12H2O(liquid) => ¼ Mg(OHh + MgCLôFhO

The MgCl₂(aq) is being reconstituted to hatf of the original MgCl₂-6H₂O by water removat and the remaining half of the MgCh-ôfhO forms from the disproportionation of Mg(0H)Cl by addition of water.

An example of a system that utilizes Mg(0H>2 generated as detailed above is shown in FIG. 38A-I. The Aspen diagram is below, and has a red rectangle around the defined “water disproportionator’’. At the top of the red rectangle, Mg(OH)Cl, stream SOLIDS-1, is leaving the décomposition reactor labeled DECOMP. Then in the module labeled MG0H2, the Mg(OH)Cl is mixed the aqueous MgC12 from the absorption column, stream RECYCLE2. They leave as a slurry from the unit as stream “4”, pass through a heat exchanger and send heat to the décomposition chamber. The stream is then named “13” which passes through a séparation unit which séparâtes the stream into stream MGCLSLRY (MgCI₂.6H2O almost) and stream SOLIDS-2, which is the Mg(OH)₂ heading to the absorption column.

V. Reaction of Group 2 Hydroxldes and CO₂ to Form Group 2 Carbonates

In another aspect of the présent disclosure, there are provided apparatuses and methods for the decarbonation of carbon dioxide sources using Group 2 hydroxides, Group 2 oxides, and/or Group 2 hydroxide chlorides as CO₂ adsorbents. In some embodiments, CO₂ is absorbed into an aqueous caustic mixture and/or solution where it reacts with the hydroxide and/or oxide salts to form carbonate and bicarbonate products. Sodium hydroxide, calcium hydroxide and magnésium hydroxide, in various concentrations, are known to readily absorb

CO₂. Thus, in embodiments of the présent invention, Group 2 hydroxides, Group 2 oxides (such as CaO and/or MgO) and/or other hydroxides and oxides, e.g., sodium hydroxîde may be used as the absorbing reagent.

For example, a Group 2 hydroxîde, e.g., obtained from a Group 2 chloride, may be used in an adsorption tower to react with and thereby capture CO₂ based on one or both of the following reactions:

	Ca(OH)2 + CO2 CaCO3 + H2O	ΔΗ = -117.92 kj/mol** AG = —79.91 kj/mol**	(24)
10	Mg(OH)2 + CO2 -> MgCO3 + H2O		(25)
		ΔΗ =-58.85 kj/mol**
		Δϋ =-16.57 kJ/mol**

*♦ Calculated at STP.

In some embodiments of the présent invention, most or neariy ail of the carbon 15 dioxide is reacted in this manner. In some embodiments, the reaction may be driven to completion, for example, through the removal of water, whether through continuous or discontinous processes, and/or by means of the précipitation of bicarbonate, carbonate, or a mixture of both types of salts. See example 1, below, providing a simulation demonstrating the ability to capture CO₂ from flue gas using an inexpensive raw material, CafCOh derived 20 from CaCl₂, to form CaCO₃.

In some embodiments, an initially formed Group 2 may undergo an sait exchange reaction with a second Group 2 hydroxîde to transfer the carbonate anion. For example: CaCl₂ + MgCOj+-> MgCl₂ + CaCOj (25a)

These methods and devices can be further modified, optimized and sealed up using 25 the principles and techniques of chemistry, chemical engineering, and/or materials science as applied by a person skilled in the art. Such principles and techniques are taught, for example, in U.S. Patent 7,727,374, U.S. Patent Application No. 11/233,509, filed September 22, 2005, U.S. Provisional Patent Application No. 60/718,906, filed September 20, 2005; U.S. Provisional Patent Application No. 60/642,698, filed January 10, 2005; U.S. Provisional 30 Patent Application No. 60/612,355, filed September 23, 2004, U.S. Patent Application No.

12/235,482, filed September 22, 2008, U.S. Provisional Application No. 60/973,948, filed September 20, 2007, U.S. Provisional Application No. 61/032,802, filed February 29, 2008,

U.S. Provisional Application No. 61/033,298, filed March 3, 2008, U.S. Provisional Application No. 61/288,242, filed January 20, 2010, U.S. Provisional Application No. 61/362,607, filed July 8, 2010, and International Application No. PCT/US08/77122, filed September 19, 2008. The entire text of each of the above-referenced disclosures (including any appendices) is specifically incorporated by reference herein.

VI. Silicate Minerais for the Séquestration of Carbon Dioxide

In aspects of the présent invention there are provided methods of sequestering carbon dioxide using silicate minerais. The silicate minerais make up one of the largest and most important classes of rock-forming minerais, constituting approximately 90 percent of the 10 crust of the Earth. They are classified based on the structure of their silicate group. Silicate minerais ail contain silicon and oxygen. In some aspects of the présent invention, Group 2 silicates may be used to accomplish the energy efficient séquestration of carbon dioxide.

In some embodiments, compositions comprising Group 2 inosilicates may be used. Inosilicates, or chain silicates, hâve interlocking chains of silicate tetrahedra with either S1O3, 15 1:3 ratio, for single chains or SUOj 1,4:11 ratio, for double chains.

In some embodiments, the methods disclosed herein use compositions comprising Group 2 inosilicates from the pyroxene group. For example, enstatite (MgSiOj) may be used.

In some embodiments, compositions comprising Group 2 inosilicates from the pyroxenoid group are used. For example, wollastonite (CaSiO₃) may be used. In some 20 embodiments, compositions comprising mixtures of Group 2 inosilicates may be employed, for example, mixtures of enstatite and wollastonite. In some embodiments, compositions comprising mixed-metal Group 2 inosilicates may be used, for example, diopside (CaMgSizOe).

Wollastonite usually occurs as a common constituent of a thermally metamorphosed 25 impure limestone. Typically wollastonite results from the following reaction (équation 26) between calcite and silica with the loss of carbon dioxide:

CaCO₃ + SiO₂ -> CaSiO₃ + CO₂ (26)

In some embodiments, the présent invention has the resuit of effectively reversing this natural process. Wollastonite may also be produced in a diffusion reaction in skam. It develops 30 when limestone within a sandstone is metamorphosed by a dyke, which results in the formation of wollastonite in the sandstone as a resuit of outward migration of calcium ions.

In some embodiments, the purity of the Group 2 inosilicate compositions may vary.

For example, it is contemplated that the Group 2 inosilicate compositions used in the disclosed processes may contain varying amounts of other compounds or minerais, including non-Group 2 métal ions. For example, wollastonite may itseif contain small amounts of iron, magnésium, and manganèse substituting for calcium.

In some embodiments, compositions comprising olivine and/or serpentine may be used. CO2 minerai séquestration processes utilizing these minerais hâve been attempted. The techniques of Goldberg et al, (2001) are incorporated herein by reference.

The minerai olivine is a magnésium iron silicate with the formula (Mg,Fe)2SiO4. When in gem-quality, it is called peridot. Olivine occurs in both mafic and ultramafic igneous rocks and as a primary minerai In certain metamorphic rocks. Mg-rich olivine is known to crystallize from magma that is rich in magnésium and low in silica. Upon crystallization, the magna forms mafic rocks such as gabbro and basait. Ultramafic rocks, such as peridotite and dunite, can be residues left after extraction of magmas and typically are more enriched in olivine after extraction of partial melts. Olivine and high pressure structural variants constitute over 50% of the Earth’s upper mande, and olivine is one of the Earth's most common minerais by volume. The metamorphism of impure dolomite or other sedimentary rocks with high magnésium and low silica content also produces Mg-rich olivine, or forsterite.

VII. Génération of Group 2 Chlorides from Group 2 Silicates

Group 2 silicates, e.g., CaSiOj, Mg S 1()3, and/or other silicates disclosed herein, may be reacted with hydrochloric acid, either as a gas or in the form of aqueous hydrochloric acid, to form the corresponding Group 2 metai chlorides (CaCl₂ and/or MgCl₂), water and sand. In some embodiments the HCl produced in équation 1 is used to regenerate the MgC!₂ and/or CaCh in équation 3. A process ioop is thereby created. Table 1 below depicts some of the common caicîum/magnesium containing silicate minerais that may be used, either alone or in combination. Initial tests by reacting olivine and serpentine with HCl hâve been successful. S1O2 was observed to precipitate out and MgCl₂ and CaCl₂ were collected.

Table 1. Calcium/Magnesium Minerais.

Minerai	Formula (std. notation)	Formula (oxide notation)	Ratio Group 2:SiO2	Ratio Group 2: total
Olivine	(Mg,FeMSiO4]	(MgOJeOhSiO2	1:1	1:2
Serpentine	MgJOHlsISUOjoJ	6MgO-4SiO2’4H2O	3:2	undefîned
Sepiolite	MgaCOHhSifiOnJCTfcO	. 3MgOMg(OH)2-6SiO2-6H2O	2:3	undefîned
Enstatite	Mg2[Si2O6]	2MgO-2SiO2	1:1	undefîned
Diopside	CaMg[Si2O6]	CaOMgO-2SiO2	1:1	undefîned
Tremolite	Ca2Mg3{[OH]Si4OI1}2	2CaO-5MgO-8SiO2H2O	7:8	undefîned
Wollastonite	CaSiO3	CaOSiO2	1:1	undefîned

See “Handbook of Rocks, Minerais & Gemstones by Walter Schumann Published 1993, Houghton Mifflin Co., Boston, New York, which is incorporated herein by reference.

VIII. Fu rth e r Embodiments

In some embodiments, the conversion of carbon dioxide to minerai carbonates may be defined by two salts. The first sait is one that may be heated to décomposition until it becomes converted to a base (hydroxide and/or oxide) and emits an acid, for example, as a gas. This same base reacts with carbon dioxide to form a caibonate, bicarbonate or basic carbonate sait.

For example, in some embodiments, the présent disclosure provides processes that react one or more salts from Tables A-C below with water to form a hydroxides, oxides, and/or a mixed hydroxide halides. Such reactions are typically referred to as décompositions. In some embodiments, the water may be in the form of liquid, steam, and/or from a hydrate of the selected sait. The steam may corne from a heat exchanger whereby heat from an immensely combustible reaction. Le. natural gas and oxygen or hydrogen and chlorine heats a stream of water. In some embodiments, steam may also be generated through the use of plant or factory waste heat. In some embodiments, the halide sait, anhydrous or hydrated, is also heated.

Table A. Décomposition Salts

	U*	Na*	K*	Rb*	Cs*
F	NC	N	4747	N	NC	N	10906	N	7490	N
CI'	3876	N	19497	N	8295	N	13616	N	7785	N
Br‘	3006	N	4336	N	9428	N	13814	N	8196	N
r	6110	N	6044	N	11859	N	9806	N	8196	N

Table B. Décomposition Salts (cont.)

	Mg*2	Ca75	Sr*2	Ba*2
F	4698	N	3433	N	10346	N	6143	N
cr	4500*	6W*	5847	2W	9855	6W	8098	2W
Br	5010	6W	2743	N	10346	6W	8114	2W
r	2020	N	4960	N	9855	6W	10890	2W

♦Subséquent tests hâve proven the heat of reaction within 1.5-4% of the thermodynamîcally derived value using TGA (thermogravinometric analysis) of heated samples and température ramp settings.

Table C. Décomposition Salts (cont)

	Mn+1	Fe+2	Co+2	Nl+Ï	Zn+2
F	3318	N	2101	N	5847	N	5847	N	3285	N
cr	5043	6W	3860	4W	3860	6W	4550	6W	8098	4W
Br*	5256	6W	11925	4W	9855	6W	5010	6W	4418	4W
r	5043	6W	3055	4W	4123	6W	5831	6W	4271	4W
soi2	NC	4W	13485	4W	3351	4W	8985	6W	8344	7W

Table D. Décomposition Salts (conL)

	Ag*	La*3
F	2168	N	13255	7W
cr	5486	N	7490	7W
Br*	6242	N	5029	7W
r	6110	N	4813	7W
SO/2	6159	N	10561	6W

For Tables A-D, the numerical data corresponds to the energy per amount of CO2 captured in kWh/tonne, NC = did not converge, and NA = data not available.

This same carbonate, bicarbonate or basic carbonate of the first sait reacts with a 10 second sait to do a carbonate/bicarbonate exchange, such that the anion of second sait combines with the cation of the first sait and the cation of the second sait combines with the carbonate/bicaibonate ion of the first sait, which forms the final carbonate/bicarbonate.

In some cases the hydroxide derived from the first sait is reacted with carbon dioxide and the second sait directly to form a carbonate/bicarbonate derived from (combined with the 15 cation of) the second sait. In other cases the carbonate/bicaibonate/basic carbonate derived from (combined with the cation of) the first sait is removed from the reactor chamber and placed in a second chamber to react with the second sait. FIG. 27 shows an embodiment of this 2-salt process.

This reaction may be bénéficiai when making a carbonate/bicarbonate when a sait of 20 the second métal is desired, and this second métal is not as capable of decomposing to form a CO2 absorbing hydroxide, and if the carbonate/bicarbonate compound of the second sait is insoluble, i.e. it précipitâtes from solution. Below is a non-exhaustive list of examples of such reactions that may be used either alone or in combination, including in combination with one or more either reactions discussed herein.

Examples for a Décomposition of a Salt-1:

2NaI + H₂O -> Na₂O + 2HI and/or Na₂O + H₂O-> 2NaOH

MgCl₂-6H₂O -> MgO + 5H₂O + 2HC1 and/or MgO + H₂O-> Mg(OH)₂

Examples of a Decarbonation:

2NaOH + CO₂ —> Na₂CO₃+H₂O and/or Na₂CO₃ + CO₂ + H₂O -> 2NaHCO₃

Mg(OH)₂ + CO₂ -> MgCO₃ + H₂O and/or Mg(OH)₂ + 2CO₂ -> Mg(HCO₃)₂ Examples of a Carbonate exchange with a Salt-2:

Na₂CO₃ + CaCl₂ -> CaCO₃j + 2NaCl

Na₂CO₃ + 2AgNO₃ -> Ag^O^-t- 2NaNO3

Ca(OH) 2 + Na₂CO₃ -> CaCO₃l + 2NaOH* * In this instance the carbonate, Na₂CO₃ is Salt-2, and the sait decomposed to form Ca(OH)₂, i.e. CaCl₂ is the Salt-1. This is the reverse of some of the previous examples in that the carbonate ion remains with Salt-1.

Known carbonate compounds include H₂CO₃, Li₂CO₃, Na₂CO₃, K₂CO₃, Rb₂CO₃, Cs₂CO₃, BcCO₃, MgCO₃, CaCO₃, MgCO₃, SrCQj, BaCO₃, MnCO₃, FeCO₃, CoC0₃, CuCO₃, ZnCO₃, Ag₂CO₃, CdCO₃, A1₂(CO₃)₃, T1₂CO₃, PbCO₃, and La₂(CO₃)₃. Group IA éléments are known to be stable bicarbonates, e.g., LiHCO₃, NaHCO₃, RbHCO₃, and CsHCO₃. Group IIA and some other éléments can also form bicarbonates, but in some cases, they may only be stable in solution. Typically rock-forming éléments are H, C, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Mg and Fe. Salts of these that can be thermally decomposed into corresponding hydroxîdes by the least amount of energy per mole of CO2 absorbing hydroxide may therefore be considered potential Salt-1 candidates.

Based on the energies calculated in Tables A-D, several salts hâve lower energies than MgCl₂’6H₂O. Table E below, summarizes these salts and the percent penalty réduction through their use relative to MgCl₂.6H₂O.

Table E: Section Lower Energy Alternative Salts

Compound	kw-hr/tonne	% réduction
MgCl2.6H2O	4500	0%
LICI	3876	16%
UBr	3006	50%
NaBr	4336	4%
Mgl2	2020	123%
CaF2	3433	31%

CaBr2	2743	64%
MnF2	3318	36%
FeFj	2102	114%
FeCI2.4H2O	3860	17%
Fel2.4H2O	3055	47%
CoCI2.6H2O	3860	17%
CoI2.6H2O	4123	9%
Co5O4.4H2O	3351	34%
ZnF2.2H2O	3285	37%
ZnBr2.4H2O	4418	2%
Znl2.4H2O	4271	5%
CdF2	3137	43%
AgF	2168	108%

The following salts specify a décomposition reaction through their respective available MSDS information.

Table F.

Compound	Décomposition Energy	Notes
MgCI2-6H2O	4500
MnCI2-4H2O	5043	only Mn*1 forms a stable carbonate
Nal*2H2O	1023	too rare
Co12-6H2O	4123	too rare
FeCI2-4H2O	3860	May oxidize to ferrie oxide, this will not form a stable carbonate
LI8r	3006	too rare
Mg(NO3)2-4H2O	1606	leaves Nox
CoSCMHjO	3351	somewhat rare ieaves SO3
CdCi2-2.5H2O	not aval.	toxic byproducts
Ca(NO3)r4H2O	2331	ieaves NO2

Compound	References
MgCI2-6H2O
MnCI2-4H2O	http://avogadro.chem.lastate.edu/MSDS/MnCI2.htm
Na12-H2O	http://www.chemicalbook.com/ProductMSDSDetailCB6170714_EN.htm
Co12-6H2O	http://www.espimetals.com/index.php/msds/527-cobalt-iodide
FeCI2-4H2O
UBr	http://www.chemcas.com/material/cas/archive/7550-35-8 vl.asp
Mg(NO3)2-4H2O	http://avogadro.chem.lastate.edu/MSDS/MgNO3-6H2O.htm

CoSO₄.4H_âO

CdCI₂-2.5H2O

Ca(NO₃)₂-4H2O http://www.chemicalbook.com/ProductMSDSDetallCB0323B42 EN.htm http://www.esplmetals.com/index.php/msds/460-cadmium-chloride http://avogadro.chem.iastate.edu/MSDS/Ca%28NO3%292-4H2O.htm

IX, Limestone Génération and Uses

In aspects of the présent invention there are provided methods of sequestering carbon dioxide in the form of limestone. Limestone is a sedimentary rock composed iargely of the minerai calcite (calcium carbonate: CaCOj). This minerai has many uses, some of which are identified below.

Limestone in powder or pulverized form, as formed in some embodiments of the présent invention, may be used as a soil conditioner (agricultural lime) to neutralize acidic soil conditions, thereby, for example, neutralizing the effects of acid rain in ecosystems. Upstream applications include using limestone as a reagent in desulfurizations.

Limestone is an important stone for masonry and architecture. One of its advantages is that it is relatively easy to eut into blocks or more elaborate carving. It is also long-lasting and stands up well to exposure. Limestone is a key ingrédient of quicklime, mortar, cernent, and concrète.

Calcium carbonate is also used as an additive for paper, plastics, paint, tiles, and other materials as both white pigment and an inexpensive filler. Purified forms of calcium carbonate may be used in toothpaste and added to bread and cereals as a source of calcium. CaCOj is also commonly used medicinally as an antacid.

Currently, the majority of calcium carbonate used in industry is extracted by mining or quarrying. By co-generating this minerai as part of carbon dioxide séquestration in some embodiments, this invention provides a non-extractive source of this important product.

X. Magnésium Carbonate Génération and Uses

In aspects of the présent invention there are provided methods of sequestering carbon dioxide in the form of magnésium caibonate. Magnésium caibonate, MgCCh, is a white solid that occurs in nature as a minerai. The most common magnésium carbonate forms are the anhydrous sait called magnesite (MgCOj) and the di, tri, and pentahydrates known as barringtonite (MgCO3-2H₂O), nesquehonite (MgCO3-3H₂O), and lansfordite (MgCOj· 5H₂O), respectively. Magnésium carbonate has a variety of uses; some of these are briefly discussed below.

Magnésium carbonate may be used to produce magnésium métal and basic refractory bricks. MgCOj is also used in flooring, fireproofing, fire extinguishing compositions, cosmetics, dusting powder, and toothpaste. Other applications are as Aller material, smoke suppressant in plastics, a reinforcing agent in neoprene rubber, a drying agent, a laxative, and for color rétention in foods. In addition, high purity magnésium carbonate is used as antacid and as an additive in table sait to keep it free flowing.

Currently magnésium carbonate is typically obtained by mining the minerai magnesite. By co-generating this minerai as part of carbon dioxide séquestration in some embodiments, this invention provides a non-extractive source of this important product.

XI. Silicon Dioxide Génération and Uses

In aspects of the présent invention there are provided methods of sequestering carbon dioxide that produce silicon dioxide as a byproduct. Silicon dioxide, also known as silica, is an oxide of silicon with a chemical formula of S1O2 and is known for its hardness. Silica is most commonly found in nature as sand or quartz, as well as in the cell walls of diatoms.

Silica is the most abundant minerai in the Earth’s crust. This compound has many uses; some of these are briefly discussed below.

Silica is used primarily in the production of window glass, drinking glasses and bottled beverages. The majority of optical fibers for télécommunications are also made from silica. It is a primary raw material for many whiteware ceramics such as earthenware, 20 stoneware and porcelain, as well as industrial Portland cernent.

Silica is a common additive in the production of foods, where it is used primarily as a flow agent in powdered foods, or to absorb water in hygroscopic applications. In hydrated form, silica is used in toothpaste as a hard abrasive to remove tooth plaque. Silica is the primary component of diatomaceous earth which has many uses ranging from filtration to 25 insect control. It is also the primary component of rice husk ash which is used, for example, in filtration and cernent manufacturing.

Thin films of silica grown on silicon wafers via thermal oxidation methods can be quite bénéficiai in microelectronics, where they act as electric insulators with high chemical stabiiity. In electrical applications, it can protect the silicon, store charge, block current, and 30 even act as a controlled pathway to limit current flow.

Silica is typically manufactured in several forms including glass, crystal, gel, aerogel, fumed silica, and colloïdal silica. By co-generating this minerai as part of carbon dioxide

séquestration in some embodiments, this invention provides another source of this important product.

XII. Séparation of Products

Séparation processes may be emptoyed to separate carbonate and bicarbonate products from the liquid solution and/or reaction mixture. By manîpulating the basic concentration, température, pressure, reactor size, fluid depth, and degree of carbonation, précipitâtes of one or more carbonate and/or bicarbonate salts may be caused to occur. Altematively, carbonate/bicarbonate products may be separated from solution by the exchange of heat energy with incoming flue-gases.

The exit liquid streams, depending upon reactor design, may include water, CaCO₃₍

MgCO₃, Ca(HCO₃)2, Mg(HCO₃)₂, Ca(OHh, Ca(OH)₂, NaOH, NaHCO₃, Na₂CO₃, and other dissolved gases in various equitibria. Dissolved trace émission components such as H₂SO4, HNO₃, and Hg may also be found. In one embodiment, removing/separating the water from the carbonate product invotves adding heat energy to evaporate water from the mixture, for 15 example, using a reboiler. Altematively, retaining a partial basic solution and subsequently heating the solution in a separating chamber may be used to cause relatively pure carbonate salts to precipitate into a holding tank and the remaining hydroxide salts to recirculate back to the reactor. In some embodiments, pure carbonate, pure bicarbonate, and mixtures of the two in equilibrium concentrations and/or in a slurry or concentrated form may then be 20 periodically transported to a truck/tank-car. In some embodiments, the liquid streams may be displaced to évaporation tanks/fields where the liquid, such as water, may be carried off by évaporation.

The release of gaseous products includes a concem whether hydroxide or oxide salts will be released safety, i.e., emitting “basic rain.” Emission of such aerosolized caustic salts 25 may be prevented in some embodiments by using a simple and inexpensive condenser/reflux unit.

In some embodiments, the carbonate sait may be precipitated using methods that are used separately or together with a water removat process. Various carbonate sait equitibria hâve characteristic ranges where, when the température is raised, a given carbonate sait, e.g., 30 CaCO₃ will naturally precipitate and collect, which makes it amenabte to be withdrawn as a slurry, with some fractional NaOH drawn off in the slurry.

ΧΙΠ. Recovery of Waste-Heat

Because certain embodiments of the présent invention are employed in the context of large émission of CO₂ in the form of flue-gas or other hot gases from combustion processes, such as those which occur at a power plant, there is ample opportunity to utilize this ’waste’ heat, for example, for the conversion of Group 2 chlorides salts into Group 2 hydroxides. For instance, a typical incoming flue-gas température (after electro-static précipitation treatment, for instance) is approximately 300 °C. Heat exchangers can lower that flue-gas to a point less than 300°C, while warming the water and/or Group 2 chloride sait to facilitate this conversion.

Generally, since the flue-gas that is available at power-plant exits at températures between 100°C (scrubbed typical), 300°C (after précipitation processing), and 900°C (précipitation entrance), or other such températures, considérable waste-heat processing can be extracted by cooling the incoming flue-gas through heat-exchange with a power-recovery cycle, for example an ammonia-water cycle (e.g., a “Kalina cycle), a steam cycle, or any such cycle that accomplishes the same thermodynamic means. Since some embodiments of the présent invention rely upon DC power to accomplish the manufacture of the reagent/absorbent, the process can be directly powered, partially or wholly, by waste-heat recovery that is accomplished without the normal transformer losses associated with converting that DC power to AC power for other uses. Further, through the use of wasteheat-to-work engines, significant efficiencies can be accomplished without an electricity génération step being employed at ail. In some conditions, these waste-heat recovery energy quantities may be found to entirely power embodiments of the présent invention.

XTV. Alternative Processes

As noted above, some embodiments of the apparatuses and methods of the présent disclosure produce a number of useful intermediates, by-products, and final products from the various reaction steps, including hydrogen chloride, Group 2 carbonate salts, Group 2 hydroxide salts, etc. In some embodiments, some or ail of these may be used in one or more of the methods described below. In some embodiments, some or ail of one of the starting materials or intermediates employed in one or more of the steps described above are obtained using one or more of the methods outlined below.

A. Use of Chlorine for the Chlorination of Group 2 Silicates

In some embodiments the chlorine gas may be liquefied to hydrochlorîc acid that is then used to chlorinate Group 2 silicate minerais. Liquéfaction of chlorine and subséquent use of the hydrochlorîc acid is particularly attractive especially in situations where the 5 chlorine market is saturated. Liquéfaction of chlorine may be accomplished according to équation 27:

Cl₂(g) + 2 H₂O (/) + hv (363 nm) -> 2 HCl (/) + WO₂ (g) (27)

In some embodiments, the oxygen so produced may be retumed to the air-inlet of the power plant itself, where it has been demonstrated throughout the course of power-industry 10 investigations that enriched oxygen-inlet plants hâve (a) higher Camot-efficiencies, (b) more concentrated CO₂ exit streams, (c) lower heat-exchange to warm inlet air, and (d) other advantages over non-oxygen-enhanced plants. In some embodiments, the oxygen may be utilized in a hydrogen/oxygen fuel cell. In some embodiments, the oxygen may serve as part of the oxidant in a turbine designed for natural gas power génération, for example, using a 15 mixture of hydrogen and natural gas.

B. Use of Chlorine for the Chlorination of Group 2 Hydroxides

In some embodiments the chlorine gas may be reacted with a Group 2 hydroxide salts to yield a mixture of a chloride and a hypochlorite salts (équation 28). For example, HCl may be sold as a product and the Group 2 hydroxide sait may be used to remove excess 20 chlorine.

Ca/Mg(OH)₂ + Cl₂ -> W Ca/Mg(OC!)₂ + ½ Ca/MgCl₂ + H₂O (28)

The Group 2 hypochlorites may then be decomposed using a cobalt or nickel catalyst to form oxygen and the corresponding chloride (équation 29).

Ca/Mg(OCI)₂ -> Ca/MgCl₂ + O₂ (29)

The calcium chloride and/or the magnésium chloride may then be recovered.

XV. Removai of other Pollutants from Source

In addition to removing CO₂ from the source, in some embodiments of the invention, the decarbonation conditions will also remove SOx and ΝΟχ and, to a lesser extent, mercury. In some embodiments of the présent invention, the incidental scrubbing of ΝΟχ, SOx, and 30 mercury compounds can assume greater économie importance; Le., by employing embodiments of the présent invention, coals that contain large amounts of these compounds can be combusted in the power plant with, in some embodiments, less resulting pollution than with higher-grade coals processed without the benefit of the CO₂ absorption process. Such principles and techniques are taught, for example, in U.S. Patent 7,727,374, U.S. Patent Application No. 11/233,509, filed September 22, 2005, U.S. Provisional Patent Application No. 60/718,906, filed September 20, 2005; U.S. Provisional Patent Application No. 60/642,698, filed January 10, 2005; U.S. Provisional Patent Application No. 60/612,355, filed September 23,2004, U.S. Patent Application No. 12/235,482, filed September 22,2008, U.S. Provisional Application No. 60/973,948, filed September 20, 2007, U.S. Provisional Application No. 61/032,802, filed February 29, 2008, U.S. Provisional Application No. 61/033,298, filed March 3, 2008, U.S. Provisional Application No. 61/288,242, filed January 20, 2010, U.S. Provisional Application No. 61/362,607, filed July 8, 2010, and International Application No. PCT/US08/77122, filed September 19, 2008. The entire text of each of the above-referenced disclosures (including any appendices) is specifically incorporated by reference herein.

XVI. Examples

The following examples are included to demonstrate some embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the présent disclosure, appreciate that many changes can be made in the spécifie embodiments which are disclosed and still obtain a like or similar resuit without departing from the spirit and scope of the invention.

Example 1 - Process Simulation of Capture CO₂ from Flue Gas Using

CaCI₂ to form CaCOj.

One embodiment of the présent invention was simulated using Aspen Plus v. 7.1 software using known reaction enthalpies, reaction free energies and defined parameters to détermine mass and energy balances and suitabie conditions for capturing CO₂ from a flue gas stream utilizing CaCl₂ and heat to form CaCOj product. These results show that it is possible to capture CO₂ from flue gas using inexpensive raw materials, CaCh and water, to form CaCOj.

Part of the defined parameters includes the process flow diagram shown in FIG. 5.

Results from the simulation suggest that it is efficient to recirculate an MgCl₂ stream to react with H₂O and heat to form MgfOHh. This Mg(OH)₂ then reacts with a saturated CaC!₂/H₂O solution and CO₂ from the flue gas to form CaCO₃, which is filtered out of the stream. The resulting MgCl₂ formed is recycled to the first reactor to begin the process again. This process is not limited to any particular source for CaCI₂. For example, it may be obtained from reacting calcium silicate with HCl to yield CaCI₂.

Constraints and parameters specified for this simulation inciude:

• The reactions were nm at 100% efficiencies with no losses. The simulations can be modifîed when pilot runs détermine the reaction efficiencies.

• Simulations did not account for impurities in the CaCI₂ feed stock or in any make-up MgCl₂ required due to losses from the system.

The results of this simulation indicate a preliminary net energy consumption of approximately 130 MM Btu/hr. Tables 2a and 2b provide mass and energy accounting for the various streams (the columns in the table) of the simulated process. Each stream corresponds to the stream of FIG. 5.

The process consists of two primary reaction sections and one solids filtration section. The first reactor heats MgCI^water solution causing it to break down into a HCI/H₂O vapor stream and a liquid stream of Mg(OHh. The HC1/H₂O vapor stream is sent to the HCl absorber column. The Mg(OHh solution is sent to reactor 2 for further processing. The chemical reaction for this reactor can be represented by the following équation:

MgCl₂ + 2 H₂O MgfOHh + 2HC1 (30)

A CaCl₂ solution and a flue gas stream are added to the MgCl₂ in reactor 2. This reaction forms CaCOj, MgCl₂ and water. The CaCO₃ précipitâtes and is removed in a filter or decanter. The remaining MgCl₂ and water are recycled to the first reactor. Additional water is added to complété the water balance required by the first reactor. The chemical reaction for this reactor can be represented by the following équation:

MgfOHh + CaCl₂ + CO₂ -> CaCO₃ (s) + MgCl₂ + H₂O (31)

The primary feeds to this process are CaCl₂, flue gas (CO₂) and water. MgC!₂ in the system is used, reformed and recycled. The only MgC!₂ make-up required is to replace small amounts that leave the system with the CaCO₃ product, and small amounts that leave with the HCl/water product.

This process is a net energy user. There is cross heat exchange to recover the heat in high température streams to preheat the feed streams. Signîficant heat recovery may be obtained by reacting the concentrated HCl thus formed with silicate minerais.

Table 2a. Mass and Energy Accounting for Simulation of Capture CO2 from Flue Gas Using CaCh to form CaCQ>

Process Stream Names *>	1	2	3	BOTTOMS	CaCI2	CaCOj	FG-IN	HjO	HjO-MgOH
Température F	485.8	151.6	250	95	77	95	104	77	536
Pressure psla	15	15	15	15	15	15	15	15	15
Vapor Frac	0	0	0.025	0	0		1	0	0
Mole Flow Ibmol/hr	1594.401	7655.248	7653.691	3568272	139.697	139.502	611.154	2220.337	1594.401
Mass Flow Ib/hr	53195.71	162514.8	162514.8	115530.1	15504	13962.37	19206	40000	53195.71
Volume Flow gal/min	38289	238.669	12389.12	114.43	14.159		30680.73	80.111	40.178
Enttialpy MMBtu/hr	-214.568	-918.028	-909.155	-574.405	-47.795		-27.903	-273.013	-205.695
HjO	1473.175	105624.1	105603	33281.39			750.535	40000	1473.172
Hï
et
HCl	trace	trace	0.001	trace					trace
COj		<0.001	0.091	0.005			6158236
CO
o2		0.055	0.055	0.055			2116.894
N2		0.137	0.137	0.137			10180.34
CaCt					15504
Ca(OH)î
CaCOs
MgtOHfe
Mg(OH)CI
MgCt
MgCO3
Ca(O)Ct
ΟάΟέΟί
Ca2+		7.797	trace	7.797
Mg2*-	11114.84	14507.52	14506.86	11942.37					11115.59
H*	<0.001	trace	trace	trace				trace	<0.001
CaOH*		<0.001	trace	<0.001
MgOH*	22.961	15.364	17.613	25.319					20.435

Process Stream Names *>	1	2	3	BOTTOMS	CaClz	CaCOj	FG-IN	h2o	H2OMgOH
HCK)
MgCOr3W
MgCys)
MgClr6W				2143325
MgCMW
CaCUs)
CaCO3(s)				13962.37		13962.37
MgCOafs)		0.174
CaCl2-6W			42.623
CaClj-4W
CaCIrZW
MgCla-SW
MgCIrW
Ca(OH)2(s)
Mg(OH)2(s)	8137.518	7.043	5.576	0.08					8139.306
CIO'
HCOa-		0.001	<0.001	0.119
cr	3244721	42352.6	42338.81	3487724					3244721
OH	<0.001	0.001	0.001	<0.001				<0.001	<0.001
CO3 2'		trace	trace	0.001
HaO	0.028	0.65	0.65	0288			0.039	1	0.028
h2
Clî
HCl	trace	trace	3 PPB	trace					trace
CO2		trace	563 PPB	40 PPB			0.321
CO
o2		336 PPB	336 PPB	473 PPB			0.11
n2		844 PPB	844 PPB	1 PPM			0.53
C3CI2					1
CatOHfe
C3CO3

Process Stream Names *>	1	2	3	BOTTOMS	CaCli	CaCOj	FG-IN	H2O	H2O-MgOH
Mg(0H)2
Mg(0H)CI
MgCI2
MgCO3
CafOJCt
CaCIjOz
Ca2*		48 PPM	trace	67 PPM
Mg^	0.209	0.089	0.089	0.103					0.209
H*	1 PPB	trace	trace	trace				trace	5 PPB
CAOH*		1 PPB	trace	1 PPB
MgOH*	432 PPM	95 PPM	108 PPM	219 PPM					384 PPM
HCIO
MgC0r3W
MgCl^s)
MgClr6W				0.186
MgClr4W
CaCl^s)
CaCO^s)				0.121		1
MgCO3(s)		1 PPM
CaClr6W			262 PPM
CaCMW
CaCfe-SW
MgClr2W
MgCIrW
CaiOHMs)
Mg(OH)2(s)	0.153	43 PPM	34 PPM	691 PPB					0.153
CIO
HCOj		5 PPB	trace	1 PPM
cr	0.61	0.261	0261	0.302					0.61
OH	trace	6 PPB	6 PPB	trace				2 PPB	trace
C03 2		trace	trace	12 PPB

Process Stream Names ->	1	2	3	BOTTOMS	CaCla	CaCOj	FG-IN	HjO	HaO-MgOH
H20	81.774	5863.026	5861.857	1847.398			41.661	2220.337	81.773
Ha
et
HCl	trace	trace	<0.001	trace					trace
COa		trace	0.002	<0.001			139.929
CO
Oa		0.002	0.002	0.002			66.155
Na		0.005	0.005	0.005			363.408
CaCt					139.697
Ca(OH)a
Q3CO3
Mg(OH)a
Mg(OH)CI
MgCt
MgCOa
Ca(0)Cla
CaCtOi
Ca2*		0.195	trace	0.195
Mg2*	457.328	596.922	596.894	491.376					457.358
H*	<0.001	trace	trace	trace				trace	<0.001
CAOH*		trace	trace	trace
MgOH*	0.556	0.372	0.426	0.613					0.495
HCIO
MgCOr3W
MgCI2(s)
MgC1a-6W				105.426
MgCla-4W
CaCt(s)
CdQO^s)				139.502		139.502
MgCO3(s)		0.002
CaCt-6W			0.195

Process Stream Names ·>	1	2	3	BOTTOMS	CaCI2	CaCOj	FG-IN	h2o	H2O-MgOH
CaClr4W
CaClr2W
MgCIrSW
MgClrW
Ca(OH)2(s)
Mg(OH)2(s)	139.533	0.121	0.096	0.001					139.564
CIO'
HCO3		<0.001	trace	0.002
cr	915211	1194.604	1194215	983.753					915211
OH'	trace	<0.001	<0.001	trace				trace	trace
CO3 2'		trace	trace	<0.001
HjO	0.051	0.766	0.766	0.518			0.068	1	0.051
h2
Ck
HQ	trace	trace	2 PPB	trace					trace
CQa		trace	271 PPB	29 PPB			0.229
CO
Oa		223 PPB	223 PPB	478 PPB			0.108
n2		640 PPB	640 PPB	1 PPM			0.595
CaCI2					1
CatOHfe
CûCOg
MgtOHfe
Mg(OH)CI
MgCI2
MgCO3
CatOJCIa
Ca2+		25 PPM	trace	55 PPM
Mg57	0287	0.078	0.078	0.138					0287
H*	49 PPB	trace	trace	trace				2 PPB	156 PPB

Process Stream Names ·>	1	2	3	BOTTOMS	CaClî	CaCOj	FG-1N	H2O	H2O-Mg0H
CaOH*		trace	trace	trace
MgOH*	349 PPM	49 PPM	56 PPM	172 PPM					310 PPM
HCIO
MgC0r3W
MgCI2(s)
MgClj-eW				0.03
MgCMW
CaCb(s)
CeCOsfs)				0.039		1
MgCOafs)		269 PPB
CaCh-GW			25 PPM
CaCMW
CaCIrZW
MgCIrSW
MgClrW
Ca(OHMs)
Mg(OHMs)	0.088	16 PPM	12 PPM	383 PPB					0.088
CIO
HCO3-		2 PPB	trace	547 PPB
CT	0.574	0.156	0.156	0.276					0.574
OIT	1 PPB	8 PPB	7 PPB	trace				2 PPB	1 PPB
CO3 Z		trace	trace	6 PPB
PH	5.319	6.955	5.875	7.557				6.999	5.152

Table 2b. Mass and Energy Accounting for Simulation of Capture CO₂ from Flue Gas Using CaCI₂ to form CaCO>

Process Stream Names ·>	HïO-IN	HO-HjO	MQ^CaClj	MgOH-O1	RETURN	RX3-VENT
Température F	77	536	250	286.8	95	95
Pressure psia	15	15	15	15	15	15
Vapor Frac	0	1	0.025	0.021	0	1

Process Stream Names->	H2O-IN	HCFHjO	Mg-CaClj	MgOH-O1	RETURN	RX3-VENT
Mole Flow Ibmol/hr	3383.073	5781.846	7655.866	3814.738	3427.371	433.305
Mass Flow Ib/hr	60947	109319.3	162515	93195.71	101567.8	12375.59
Volume Flow gal/min	122.063	512251.6	12240.14	5364.891	104.123	21428.56
Enthalpy MMBtu/hr	-415.984	-561.862	-909.177	-487.581	-502.044	-0.364
Hz0	60947	99124.11	105634.7	41473.17	33262.52	59.861
h2
CIj
HO		10195.18	0.087	0.009	trace	trace
C02					trace	18.689
CO
□2					0.055	2116.839
Na					0.137	10180.2
CaCl?
Ca(OH)î
C3CO3
Mg(OH)2
Mg(OH)CI
MgClî
MgCOs
Ca(O)Cl2
C3CI2O2
Ca2*					7.797
Mt?*			14519.48	11116.3	11938.09
H*	trace		<0.001	trace	trace
CaOH*					<0.001
MgOH*			0.112	17.999	25.309
HCIO
MgCOr3W
MgCl^s)

Process Stream Names ->	H2O-IN	HCFH2O	Mg-CsClj	MgOH-O1	RETURN	RX3-VENT
MgCt-6W					21468.81
MgCt-4W
CaCt(s)
CaCOsts)
MgCO3(s)					0.175
CaClr6W
CaCt-4W
CaC12-2W
MgClr2W
MgCIrW
Ca(OHk(s)
Mg(OHWs)				8141.025	0.024
cio·
HCO3*					trace
cr			42360.62	32447.2	34864.84
OK	<0.001		trace	<0.001	<0.001
CO3 2'					trace
Mass Frac
H2O	1	0.907	0.65	0.445	0.327	0.005
Hî
et
HCl		0.093	534 PPB	92 PPB	trace	trace
CO2					trace	0.002
CO
o2					538 PPB	0.171
n2					1 PPM	0.823
CaCt
Ca(OH)2
CaCO3
MgtOHfe

Process Stream Names->	h2o-in	HCFHzO	Mg-CaCI2	MgOH-O1	RETURN	RX3-VENT
Mg(0H)CI
MgCI2
MgCO3
Ca(0)CI2
CaClîOj
Ca2*					77 PPM
Mg2*			0.089	0.119	0.118
H*	trace		2PPB	trace	trace
CaOH*					1 PPB
MgO H*			689 PPB	193 PPM	249 PPM
HCIO
MgC0r3W
MgCbts)
MgCl2-6W					0.211
MgCI2-4W
CaC«s)
OsCO^s)
MgCO3(s)					2 PPM
CaClr6W
CaCMW
CaClr2W
MgClr2W
MgClyW
Ca(OHk(s)
Mg(OHMs)				0.087	240 PPB
CIO'
HCO3·					trace
cr			0.261	0.348	0.343
□H'	2PPB		trace	2 PPB	trace
CO3 Z‘					trace

Process Stream Names ->	HîO-IN	hci-h2o	Mg-CaClj	MgOH-O1	RETURN	RX3-VENT
HzO	3383.073	5502.224	5863.617	2302.111	1846.35	3.323
h2
Clz
HCl		279.622	0.002	<0.001	trace	trace
CO2					trace	0.425
CO
o2					0.002	66.154
n2					0.005	363.404
CaCfe
Ca(OH)a
C3CO3
Mg(OH)j
Mg(OH)CI
MgCt
MgCO3
Ca(0)Cl2
CdCljOj
Caz+					0.195
Mg^			597.414	457.388	491.201
H*	trace		<0.001	trace	trace
CaOH*					trace
MgOH*			0.003	0.436	0.613
HCIO
MgC0r3W
MgCWs)
MgCI2-6W					105.601
MgCMW
CaCys)
CâCOsfs)
MgCOa(s)					0.002

Process Stream Names-)	HaO-IN	HCFHaO	Mg-CaClj	MgOH-01	RETURN	RX3-VENT
CaCI?-6W
CaClz-4W
CaClr2W
MgClr2W
MgClrW
CatOHhts)
MgtOHMs)				139.593	<0.001
CIO*
hco3*					trace
CT			1194.83	915.211	983.403
OH*	trace		trace	trace	trace
COj2·					trace
HîO	1	0.952	0.766	0.603	0.539	0.008
h2
Cia
HCl		0.048	311 PPB	62 PPB	trace	trace
COa					trace	980 PPM
CO
Oa					498 PPB	0.153
Na					1 PPM	0.839
CaCla
Ca(OH)j
CaCO3
Mg(OH)a
Mg(OH)Cf
MgCla
MgCO3
Ca(O)Cla
CâCljOz
Ca2*					57 PPM

Process Stream Names->	H2O4N	HCFH2O	Mg-CaCt,	MgOH-O1	RETURN	RX3-VENT
Mg2*			0.078	0.12	0.143
H*	2PPB		43 PPB	trace	trace
CaOH*					trace
MgOH*			354 PPB	114 PPM	179 PPM
HCIO
MgC0r3W
MgClifs)
MgCIrGW					0.031
MgClr4W
CaCl2(s)
CaCO3(s)
MgCO3{s)					607 PPB
CaCl?-6W
CaClr4W
CaCIrZW
MgClr2W
MgClrW
Ca(OH)s(s)
Mg(OHHs)				0.037	122 PPB
CIO*
HCO3*					trace
cr			0.156	0.24	0.287
OH*	2PPB		trace	2 PPB	trace
O O «M					trace
PH	6.999		3.678	5.438	7.557

Example 2 (Case 1)-Process Simulation of Magnésium Ion Catalyzed Capture CO₂ from Flue Gas Using CaCl₂ to form CaCOj.

Results from the simulation suggest that it is efficient to heat a MgCI₂-6H₂O stream in three separate déhydration reactions, each in its own chamber, foilowed by a décomposition 5 reaction, also in its own chamber, to form Mg(0H)Ci and HCl, i.e. total of four chambers. The Mg(0H)Ci is reacted with H₂O to form MgCl₂ and Mg(0H)₂, which then reacts with a saturated CaCl₂/H₂O solution and CO₂ from the flue gas to form CaCO3, which is filtered out of the stream. The resulting MgCl₂-6H₂O formed is recycled along with the eariier product to the first reactor to begin the process again.

This process is not limited to any particular source for CaCI₂. For example, it may be obtained from reacting calcium silicate with HCl to yield CaCl₂.

Constraints and parameters specified for this simulation include:

• The reactions were run at 100% efficiencies with no losses. The simulations can be modified when pilot runs détermine the reaction efficiencies.

· Simulations did not account for impurities in the CaCl₂ feed stock or in any make-up MgCI₂ required due to losses from the system.

• Part of the defined parameters include the process flow diagram shown in FIG. 6.

The results of this simulation îndicate a preliminary net energy consumption of 5946 20 kwh/tonne CO₂. Table 3 provides mass and energy accounting for the various strcams of the simulated process. Each stream corresponds to the stream of FIG. 6.

The process consists of two primary reactors and one solids filtration section. The first reactor heats MgCI₂-6H₂O causing it to break down into a HC1/H₂O vapor stream and a solid stream of Mg(OH)Cl. The HC1/H₂O vapor stream is sent to a heat exchanger to recover 25 extra heat. The Mg(0H)2 formed from the Mg(OH)Cl is sent to reactor 2 for further processing. Chemical reaction(s) occurring in this reactor include the following:

MgCI₂-6H₂O + Δ -> Mg(OH)Cl + 5 Η₂Ο| + HCiî (32)

Mg(0H)Cl(a<7) -> Mg(OH)₂ + MgCl₂ (33)

A CaCl₂ solution and a flue gas stream are added to the Mg(OH)₂ in reactor 2. This 30 reaction forms CaCCh, MgCl₂ and water. The CaCOj précipitâtes and is removed in a filter or decanter. The remaining MgCl₂ and water are recycled to the first reactor. Additional

water is added to complété the water balance required by the first reactor. Chemical reaction(s) occurring in this reactor include the following:

Mg(OH)₂ + CaCI₂ + CO₂ -> CaCO₃ Φ(ί) + MgCl₂ + H₂O (34)

The primary feeds to this process are CaCl₂, flue gas (CO₂) and water. MgCl₂ in the 5 system is used, reformed and recycled. The only MgC!₂ make-up required is to replace small amounts that leave the system with the CaCO₃ product, and small amounts that leave with the HCl/water product.

This process is a net energy user. The amount of energy is under investigation and optimization. There is cross heat exchange to recover the heat în high température streams to 10 preheat the feed streams.

The steps for this process (Case 1) are summarized below:

CASE 1
3 STEP Déhydration then Décomposition
Hexahydrate Is dehydrated In 3 separate chambers. Step 1 hex to tetra, Step 2 tetra to di, Step 3 di to mono. Monohydrate Is decomposed Into 80% Mg(OH)Cl 20% MgCi2 in a fourth chamber.
CO2 Absorbed	53333	MTPY
CaCl2	134574	MTPY
HCI Dry	88368	MTPY
CaCOa	105989	MTPY
Hexahydrate recycled	597447	MTPY
HEX TO TETRA (100 *C)	1757	kWh/tonne CO2
TETRA TO DI (125C*)	2135	kWh/tonne CO2
DI TO MONO (160 *C & HCl PP)	1150	kWh/tonne CO2
DECOMPOSITION (130’C)	1051	kWh/tonne CO2
TO 80% Mg(0H)CI 20% MgCI2
YIELDS 90% HCiVAPOR
	0.9	MW
Heat Recovery	148	kWh/tonne CO2
from 28% HCl vapor
TOTAL	5946	kWh/tonne CO2

Table 3a. Mass and Energy Accounting for Case 1 Simulation.

Process Stream Names ->	C3CÎ2	CaCOj	FLUEGAS	HzO	HïO-1	HiO-2	HCI-PP	HCIVAPOR
Température C	25	95	104	25	100	125	160	130
Pressure psia	14.7	14.7	15.78	14.7	16.166	16.166	16.166	14.696
MassVFrac	0	0	1	0	1	1	1	1
MassSFrac	1	1	0	0	0	0	0	0
Mass Flow tonne/year	134573.943	121369558	166332.6	290318.99	105883.496	105890.399	17179526	97647.172
Volume Flow gal/min	30.929	22.514	76673298	8099.644	82228.086	87740.919	10242.935	48861.42
EnthalpyMW	-30599	-46.174	-17.479	-146.075	•44.628	44.47	-3258	-10.757
Density lb/cuft	136.522	169.146	0.068	1.125	0.04	0.038	0.053	0.063
H2O	0	0	6499.971	290318.99	105883.496	105885.779	5681299	9278.695
Hî	0	0	0	0	0	0	0	0
Ck	0	0	0	0	0	0	0	0
Ha	0	0	0	0	0	4.62	11498227	88368.477
CO2	0	0	53333.098	0	0	0	0	0
CO	0	0	0	0	0	0	0	0
02	0	0	18333252	0	0	0	0	0
Nz	0	0	88166278	0	0	0	0	0
Caa2	134573.943	80.499	0	0	0	0	0	0
CatOHh	0	0	0	0	0	0	0	0
CaCO3	0	121289.059	0	0	0	0	0	0
MgCOa	0	0	0	0	0	0	0	0
Ca(O)CI2	0	0	0	0	0	0	0	0
MgC12	0	0	0	0	0	0	0	0
MgCfe*W	0	0	0	0	0	0	0	0
MgCI2*2W	0	0	0	0	0	0	0	0
MgCfeMW	0	0	0	0	0	0	0	0
MgCI2‘6W	0	0	0	0	0	0	0	0

HCl VAPOR

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Table 3b. Mass and Energy Accounting for Case 1 Simulation.

Process Stream Names ·>	MgCWW	MgCMW	MgClr6W	RECYCIE1	RX2-VENT	SLURRY	SOUDS-1	SOUDS-2	VAPOR
Température eC	125	100	104	95	95	95	160	130	160
Pressure psia	16.166	16.166	14.696	14.7	14.7	14.7	22.044	14.696	22.044
MassVFrac	0	0	0	0	1	0	0	0	1
Mass SFrac	1	1	1	0.998	0	0.999	1	1	0
Mass Flowtonne/year	385672.688	491563.087	597446.583	598447.468	106499.178	719817.026	332737.843	235090.671	70114.371
Volume Flow gal/min	39.902	39.902	116.892	147.062	56469.408	167.321	39.902	43.473	42506.729
EnthalpyMW	-117.767	-175272	-230.554	-231212	0241	-277.487	-88.626	-71.431	-25.379
Density Ib/cuft	303.274	386.542	160.371	127.684	0.059	134.984	261.649	169.678	0.052
HzO	0	0	0	1000	0	1000	0	0	58620.764
h2	0	0	0	0	0	0	0	0	0
Ch	0	0	0	0	0	0	0	0	0
HQ	0	0	0	0	0	0	0	0	11493.607
CO?	0	0	0	0	0.532	0	0	0	0
CO	0	0	0	0	0	0	0	0	0
Oî	0	0	0	0.165	18333.088	0.165	0	0	0
Nî	0	0	0	0.72	88165.558	0.72	0	0	0
CaCh	0	0	0	0	0	80.499	0	0	0
CafOHJî	0	0	0	0	0	0	0	0	0
CaCOj	0	0	0	0	0	121289.059	0	0	0
MgCOa	0	0	0	0	0	0	0	0	0
CafOJCh	0	0	0	0	0	0	0	0	0
MgCb	0	0	0	0	0	0	0	49037.72	0
MgCW	0	0	0	0	0	0	332737.843	0	0
MgC12*2W	385662.96	0	0	0	0	0	0	0	0
MgClï‘4W	0	491563.087	0	0	0	0	0	0	0

VAPOR

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Process Stream Names ->	MgCh-ZW	MgCMW	MgClr6W	RECYCIE1	RX2-VENT	SLURRY	SOLIDS-1	SOUDS-2	VAPOR
HîO	0	0	0	1.76	0	1.76	0	0	103.182
Ha	0	0	0	0	0	0	0	0	0
Cia	0	0	0	0	0	0	0	0	0
HCl	0	0	0	0	0	0	0	0	9.996
COa	0	0	0	0	0	0	0	0	0
CO	0	0	0	0	0	0	0	0	0
Oa	0	0	0	0	18.168	0	0	0	0
Na	0	0	0	0.001	99.799	0.001	0	0	0
CaOa	0	0	0	0	0	0.023	0	0	0
Ca(OH)a	0	0	0	0	0	0	0	0	0
CaCOs	0	0	0	0	0	38.427	0	0	0
MgCOa	0	0	0	0	0	0	0	0	0
CafOJCk	0	0	0	0	0	0	0	0	0
MgCb	0	0	0	0	0	0	0	16.332	0
MgCla*W	0	0	0	0	0	0	93.186	0	0
MgCla’SW	93.182	0	0	0	0	0	0	0	0
Mgda*4W	0	93 J 86	0	0	0	0	0	0	0
Mgda*6W	0	0	93.186	93.186	0	93.186	0	0	0
Mg(OH)CI	0.004	0	0	0	0	0	0	76.854	0
Mg(OH)a	0	0	0	0	0	0	0	0	0
MgO	0	0	0	0	0	0	0	0	0
MgHCOs*	0	0	0	0	0	0	0	0	0

Example 3 - Process Simulation of Magnésium Ion Catalyzed Capture CO₂ from Flue Gas Using CaCI₂ to form CaCOj.

Part of the defined parameters Includes the process flow diagram shown in FIG. 7. Results from the simulation suggest that it is efficient to heat a MgCl₂-6H₂O stream to form Mg(OH)C! in two separate déhydration reactions, each in their own chambers followed by a décomposition reaction, also in its own chamber to form Mg(OH)Cl and HCl, i.e. a total of three chambers. The Mg(OH)Cl is reacted with H₂O to form MgCI₂ and MgtOHh, which then reacts with a saturated CaCl₂/H₂O solution and CO₂ from the flue gas to form CaCOj, which is fiitered out of the stream. The resulting MgCl₂.6H₂O formed is recycled to the first reactor to begin the process again. This process is not limited to any particular source for CaCl₂. For example, it may be obtained from reacting calcium silicate with HCl to yield CaCl₂.

Constraints and parameters specified for this simulation include:

• The reactions were run at 100% efficiencies with no losses. The simulations can be modified when pilot runs détermine the reaction efficiencies.

• Simulations did not account for impurities in the CaCl₂ feed stock or in any make-up MgC!₂ required due to losses from the system.

The results of this simulation indicate a preliminary net energy consumption of 4862 kwh/tonne CO₂. Table 4 provides mass and energy accounting for the various streams of the simulated process. Each stream corresponds to the stream in FIG. 7.

The process consists of two primary reactors and one solids filtration section. The first reactor heats MgCl₂.6H₂O causing it to break down into a HCÎ/H₂O vapor stream and a solid stream of Mg(OH)Cl. The HCÎ/H₂0 vapor stream is sent to a heat exchanger to recover extra heat. The MgfOHh formed from the Mg(OH)Cl is sent to reactor 2 for further processing. Chemical reaction(s) occurrmg in this reactor include the following:

MgCl₂-6H₂O + Δ -> Mg(OH)Cl + 5 H₂OÎ + HC1| (35)

2Mg(OH)C!(a^)-»Mg(OH)₂ + MgC12 (36)

A CaCl₂ solution and a flue gas stream arc added to the Mg(OHh in reactor 2. This reaction forms CaCOj, MgCl₂ and water. The CaCOj précipitâtes and is removed in a filter or decanter. The remaining MgCI₂ and water are recycled to the first reactor. Additional water is added to complété the water balance required by the first reactor. Chemical reaction(s) occurring in this reactor include the following:

Mg(OH)₂ + CaCl₂ + CO₂ -> CaCO₃ Φ(τ) + MgCl₂ + H₂O (37)

The primary feeds to this process are CaCl₂₍ flue gas (CO₂) and water. MgCl₂ in the system is used, reformed and recycled. The only MgCl₂ make-up required is to replace small amounts that leave the system with the CaCO₃ product, and small amounts that leave with the 5 HCl/water product.

This process is a net energy user. The amount of energy is under investigation and optimization. There is cross heat exchange to recover the heat in high température streams to preheat the feed streams.

The steps for this process (Case 2) are summarized below:

CASE 2 2 STEP Déhydration then Décomposition
Hexahydrate Is dehydrated In 2 separate chambers. Step 1 hex to tetra, Step 2 tetra to dl. Di-hydrate
Is decomposed into 100% Mg(OH)CI.
CO] Absorbed	53333	MTPY
CaCI2	134574	MTPY
HCl Dry	88368	MTPY
CaCOj	105989	MTPY
Hexahydrate recycled	492737	MTPY
HEX TO TETRA (100 *C)	1445	kWh/tonne CO2
TETRA TODI (125 *C)	1774	kWh/tonne CO2
DI-HYDRATE DEHYDRATION & DECOMPOSITION T0100% Mg(OH)Ci (130 *C) YEILDS66% HCIVAPOR	1790	kWh/tonne CO2
NO CARRIER MgCi2 = BETTER OVERALL EFFICIENCY NO USE OF HCl PP	0.9
Heat Recovery from 28% HCl vapor	148	kWh/tonne CO2
TOTAL	4862	kWh/tonne CO2

Table 4a. Mass and Energy Accounting for Case 2 Simulation.

Process Stream Names->	5	7	8	CaCk	CaCOj	FLUEGAS	HjO	HjO-1	HtO-2	HCl Vapor
Température’C	98	114.1	101	25	95	40	25	100	125	130
Pressure psia	14.696	14.696	14.696	14.7	14.7	15.78	14.7	14.696	22044	14.696
MassVFrac	0	0	1	0	0	1	0	1	1	1
Mass SFrac	1	1	0	1	1	0	0	0	0	0
Mass Flow tonne/year	492736.693	405410.587	306683.742	134573.943	121369558	1663326	234646.82	87326.106	87329.947	132027.689
Volume Flow gal/min	96.405	32.909	224394519	30.929	22514	63660.018	6546.44	74598258	53065241	80593.954
Errthalpy MW	-190292	-144291	-98.931	-30.599	-46.174	-17.821	-118.063	-36.806	-36.675	-25J87
Density Ib/cuft	160.371	386542	0.043	136.522	169.146	0.082	1.125	0.037	0.052	0.051
HîO	0	0	218315265	0	0	6499.971	234646.82	87326.106	87326.106	43663.053
h2	0	0	0	0	0	0	0	0	0	0
Cl2	0	0	0	0	0	0	0	0	0	0
HCl	0	0	88368.477	0	0	0	0	0	3.841	88364.636
C02	0	0	0	0	0	53333.098	0	0	0	0
CO	0	0	0	0	0	0	0	0	0	0
02	0	0	0	0	0	18333252	0	0	0	0
N2	0	0	0	0	0	88166278	0	0	0	0
CaCh	0	0	0	134573.943	80.499	0	0	0	0	0
CaCOHh	0	0	0	0	0	0	0	0	0	0
CaCOs	0	0	0	0	121289.059	0	0	0	0	0
MgCOa	0	0	0	0	0	0	0	0	0	0
Ca(0)Cl2	0	0	0	0	0	0	0	0	0	0
MgCk	0	0	0	0	0	0	0	0	0	0
MgCl2*W	0	0	0	0	0	0	0	0	0	0
MgCI2*2W	0	0	0	0	0	0	0	0	0	0
MgCbMW	0	405410587	0	0	0	0	0	0	0	0

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Process Stream Names*)	5	7	8	CaCh	CaCOi	FLUEGAS	H2O	HzO-1	H2O-2	HCl Vapor
Hz	0	0	0	0	0	0	0	0	0	0
Ch	0	0	0	0	0	0	0	0	0	0
HCl	0	0	76.854	0	0	0	0	0	0.003	76.851
COz	0	0	0	0	0	38.427	0	0	0	0
CO	0	0	0	0	0	0	0	0	0	0
O2	0	0	0	0	0	18.168	0	0	0	0
Nz	0	0	0	0	0	99.8	0	0	0	0
CaCh	0	0	0	38.45	0.023	0	0	0	0	0
Ca(OHh	0	0	0	0	0	0	0	0	0	0
CaCO3	0	0	0	0	38.427	0	0	0	0	0
MgCOs	0	0	0	0	0	0	0	0	0	0
Ca(O)Clz	0	0	0	0	0	0	0	0	0	0
MgCh	0	0	0	0	0	0	0	0	0	0
Mgdz*W	0	0	0	0	0	0	0	0	0	0
MgGlz*2W	0	0	0	0	0	0	0	0	0	0
MgCh*4W	0	76.854	0	0	0	0	0	0	0	0
MgClz*6W	76.854	0	0	0	0	0	0	0	0	0
Mg(OH)Q	0	0	0	0	0	0	0	0	0	0
MgtOHh	0	0	0	0	0	0	0	0	0	0
MgO	0	0	0	0	0	0	0	0	0	0
MgHCOa*	0	0	θ	1 0	0	0	0	0	0	0

Table 4b. Mass and Energy Accounting for Case 2 Simulation.

Process Stream Names -)	UQUID	MgClz*4W	MgCIrGW	RECYCLE1	RX2-VENT	SLURRY	SOU DS-1	SOUDS-2	VAPOR
Température °C	94.9	100	75	95	95	95	125	130	118.1
Pressure psia	14.696	14.696	14.696	14.7	14.7	14.7	22.044	14.696	14.696
MassVFrac	0.979	0	0	0	1	0	0	0	1

Process Stream Names ->	LIQUID	MgCHW	MgCHW	RECYCLE1	RX2-VENT	SLURRY	SOUDS-1	SOUDS-2	VAPOR
Mass SFrac	0	1	1	0.998	0	0.998	1	1	0
Mass Flow tonne/year	306683.742	405410587	492736.693	493737.578	106499.178	615107.136	318080.64	186052951	306683.742
Volume Flowgal/min	215496.035	32.909	96.405	126.575	56469.408	146.834	32.909	32.909	234621.606
Enthalpy MW	-99.487	-144553	-190.849	-190.859	0241	-237.034	-97.128	-61.083	-98.668
Density Ib/cuft	0.045	386.542	160.371	122.394	0.059	131.442	303277	177.393	0.041
HzO	218315265	0	0	1000	0	1000	0	0	218315265
Ha	0	0	0	0	0	0	0	0	0
Cia	0	0	0	0	0	0	0	0	0
Ha	88368.477	0	0	0	0	0	0	0	88368.477
COa	0	0	0	0	0.532	0	0	0	0
CO	0	0	0	0	0	0	0	0	0
Oa	0	0	0	0.165	18333.088	0.165	0	0	0
Na	0	0	0	0.72	88165.558	0.72	0	0	0
CaCla	0	0	0	0	0	80.499	0	0	0
Ca(OH)a	0	0	0	0	0	0	0	0	0
CaCOj	0	0	0	0	0	121289.059	0	0	0
MgCOs	0	0	0	0	0	0	0	0	0
Ca(O)Ct2	0	0	0	0	0	0	0	0	0
MgCla	0	0	0	0	0	0	0	0	0
Mga*W	0	0	0	0	0	0	0	0	0
MgOa*2W	0	0	0	0	0	0	318077568	0	0
MgCla*4W	0	405410.587	0	0	0	0	0	0	0
MgCk*6W	0	0	492736.693	492736.693	0	492736.693	0	0	0
Mg(OH)CI	0	0	0	0	0	0	0	186052.951	0
Mg(OH)a	0	0	0	0	0	0	3.072	0	0
MgO	0	0	0	0	0	0	0	0	0
MgHCO?	0	0	0	0	0	0	0	0	0
Mass Frac

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Example 4 - Process Simulation of Magnésium Ion Catalyzed Capture CO₂ from Flue Gas Using CaCh to Form CaCOj.

Part of the defined parameters include the process flow diagram shown in FIG. 8. Results from the simulation suggest that it is efficient to heat a MgCh’ôfyO stream to form MgO in a single chamber. The MgO is reacted with H2O to form Mg(OHh, which then reacts with a saturated CaCh/HîO solution and CO2 from the flue gas to form CaCO₃, which is filtered out of the stream. The resulting MgCh'6H₂O formed is recycled to the first reactor to begin the process again. This process is not limited to any particular source for CaCh· For example, it may be obtained from reacting calcium silicate with HCl to yield CaCh·

Constraints and parameters specified for this simulation include:

• The reactions were run at 100% effïciencies with no losses. The simulations can be modified when pilot runs détermine the reaction effïciencies.

• Simulations did not account for impurities in the CaCh feed stock or in any make-up MgCh required due to losses from the system.

The results of this simulation indicate a preliminary net energy consumption of 3285 kwh/tonne CO2. Table 5 provides mass and energy accounting for the various streams of the simulated process. Each stream corresponds to the stream of FIG. 8.

The process consists of two primary reactors and one solids filtration section. The first reactor heats MgCh’ô^O causing it to break down into a HCI/H2O vapor stream and a solid stream of MgO. The HCI/H2O vapor stream is sent to a heat exchanger to recover extra heat. The Mg(OH>2 formed from the MgO is sent to reactor 2 for further processing. Chemical reaction(s) occurring in this reactor include the following:

MgCl2'6H₂O + Δ —> MgO + 5 H₂Oî + 2 HClf (38)

MgO + H2O -> Mg(OH)₂ (39)

A CaCh solution and a flue gas stream are added to the Mg(OH)2 in reactor 2. This reaction forrns CaCO₃, MgCh and water. The CaCO₃ précipitâtes and is removed in a filter or decanter. The remaining MgCh and water are recycled to the first reactor. Additional water is added to complété the water balance required by the first reactor. Chemical reaction(s) occurring in this reactor include the following::

Mg(OH)2 + CaCh + CO₂ -> CaCO₃ ψ(ί) + MgCh + H₂O (40)

The primary feeds to this process are CaCh, flue gas (CO2) and water. MgCh in the system is used, reformed and recycled. The only MgCh make-up required is to replace small amounts that leave the system with the CaCOj product, and small amounts that leave with the HCl/water product.

This process is a net energy user. The amount of energy is under investigation and optimization. There is cross heat exchange to recover the heat in high température streams to 5 preheat the feed streams.

The steps for this process (Case 3) are summarized below:

CASE 3 Combined Dehydratlon/Decomposltlon to MgO
Hexahydrate Is dehydrated and decomposed simultaneously at 450C. Reactor yellds 100% MgO.
CO2 Absorbed	53333	MTPY
CaCI2	134574	MTPY
HCIOry	88368	MTPY
CaCO3	105989	MTPY
Hexahydrate recycled HEXAHYORATE	246368	MTPY
DEHYDRATION & DECOMPOSITION TO 100% MgO {450 *C) YIELDS44.7% HCIVAPOR RECYCLES HALF AS MUCH HEXAHYORATE BUT NEEOS HIGH QUAUTY HEAT	3778	kWh/tonne CO2
Heat Recovery from 45% HCl vapor	493	kWh/tonne CO2
TOTAL	3285	kWh/tonne CO2

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Table 5a. Mass and Energy Accounting for Case 3 Simulation.

Process Stream Names ->	CaCh	CaCOi	FLUEGAS	HzO	HCIVAP	MgCh	MgClr6W
Température ’C	25	95	104	25	120	353.8	104
Pressure psia	14.7	14.7	15.78	14.7	14.696	14.7	14.7
MassVFrac	0	0	1	0	1	0	0
Mass SFrac	1	1	0	0	0	1	1
Mass Flow tonne/year	134573.943	121369.558	166332.6	125489.188	197526.11	246368.347	246368.347
Volume Flow gattnin	30.929	22514	76673298	3501.038	137543.974	48203	48203
Enthalpy MW	•30.599	•46.174	-17.479	-63.14	-52.762	-92.049	-95.073
Density Ib/cuft	136.522	169.146	0.068	1.125	0.045	160.371	160.371
HjO	0	0	6499.971	125489.188	109157.633	0	0
H2	0	0	0	0	0	0	0
Ch	0	0	0	0	0	0	0
HQ	0	0	0	0	88368.477	0	0
CO2	0	0	53333.098	0	0	0	0
CO	0	0	0	0	0	0	0
02	0	0	18333252	0	0	0	0
N2	0	0	88166278	0	0	0	0
CaCfe	134573.943	80.499	0	0	0	0	0
Ca(0H)2	0	0	0	0	0	0	0
CaCOs	0	121289.059	0	0	0	0	0
MgCOa	0	0	0	0	0	0	0
Ca(0)Cf2	0	0	0	0	0	0	0
MgCt	0	0	0	0	0	0	0
MgCI2*W -	0	0	0	0	0	0	0
MgC12*2W	0	0	0	0	0	0	0
MgCI2*4W	0	0	0	0	0	0	0
MgO>*6W	0	0	0	0	0	246368.347	246368.347

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Process Stream Names ->	CaCb	CaCOj	FLUE GAS	HzO	HCIVAP	MgCh	MgCh-6W
ça	0	0	38.427	0	0	0	0
CO	0	0	0	0	0	0	0
Oî	0	0	18.168	0	0	0	0
Nî	0	0	99.8	0	0	0	0
CaCh	38.45	0.023	0	0	0	0	0
Ca(OH)z	0	0	0	0	0	0	0
CaCOs	0	38.427	0	0	0	0	0
MgCOa	0	0	0	0	0	0	0
Ca(0)Cl2	0	0	0	0	0	0	0
MgCfe	0	0	0	0	0	0	0
MgCl2*W	0	0	0	0	0	0	0
Mga*2W	0	0	0	0	0	0	0
MgCI2*4W	0	0	0	0	0	0	0
MgCk*6W	0	0	0	0	0	38.427	38.427
Mg(OH)CI	0	0	0	0	0	0	0
MgfOHh	0	0	0	0	0	0	0
MgO	0	0	0	0	0	0	0

Table 5b. Mass and Energy Accounting for Case 3 Simulation.

Process Stream Names ->	Mg(OH)CI1	Mg(0H)Ct2	RECYCLE1	RECYCLE2	RECYCLE3	RX2-VENT	SLURRY	VAPOR	VENT
Température “C	450	100	95	140	140	95	95	450	140
Pressure psia	14.696	14.696	14.7	14.7	14.7	14.7	14.7	14.696	14.7
MassVFrac	0	0	0	0.004	0	1	0	1	1
Mass SFrac	1	1	0.996	0.996	1	0	0.997	0	0
Mass Flowtonne/year	48842237	48842237	247369231	247369231	246368.347	106499.178	368738.79	197526.11	1000.885
Volume Flow gal/min	6.851	6.851	78.372	994232	48203	56469.408	98.632	252994.849	946.03
Enthalpy MW	-22.38	-23	•95.676	-95.057	-94.638	0241	-141.851	•49.738	-0.419

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Process Stream Names ->	Mg(0H)O1	Mg(0H)CI2	RECYCLE1	RECYCLE2	RECYCLE3	RX2-VENT	SLURRY	VAPOR	VENT
Density !b/cuft	223.695	223.695	99.036	7.807	160.371	0.059	117.304	0.024	0.033
HjO	0	0	1000	1000	0	0	1000	109157.633	1000
Hj	0	0	0	0	0	0	0	0	0
Ch	0	0	0	0	0	0	0	0	0
HCl	0	0	0	0	0	0	0	88368.477	0
CO2	0	0	0	0	0	0.532	0	0	0
CO	0	0	0	0	0	0	0	0	0
Ch	0	0	0.165	0.165	0	18333.088	0.165	0	0.165
n2	0	0	0.72	0.72	0	88165558	0.72	0	0.72
CaClj	0	0	0	0	0	0	80.499	0	0
CatOHb	0	0	0	0	0	0	0	0	0
CaCOj	0	0	0	0	0	0	121289.059	0	0
MgCOa	0	0	0	0	0	0	0	0	0
Ca(0)Cl2	0	0	0	0	0	0	0	0	0
MgCb	0	0	0	0	0	0	0	0	0
MgCI2*W	0	0	0	0	0	0	0	0	0
MgCb*2W	0	0	0	0	0	0	0	0	0
MgCbMW	0	0	0	0	0	0	0	0	0
MgClî*6W	0	0	246368.347	246368.347	246368.347	0	246368.347	0	0
Mg(OH)CI	0	0	0	0	0	0	0	0	0
MgtOHb	0	0	0	0	0	0	0	0	0
MgO	48842237	48842237	0	0	0	0	0	0	0
HjO	0	0	0.004	0.004	0	0	0.003	0.553	0.999
h2	0	0	0	0	0	0	0	0	0
Ch	0	0	0	0	0	0	0	0	0
HCl	0	0	0	0	0	0	0	0.447	0
CO2	0	0	0	0	0	0	0	0	0
CO	0	0	0	0	0	0	0	0	0

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Process Stream Names ->	Mg(0H)Ct1	Mg(0H)CI2	RECYCLE1	RECYCLE2	RECYCLE3	RX2-VENT	SLURRY	VAPOR	VENT
MgCfe	0	0	0	0	0	0	0	0	0
MgOTW	0	0	0	0	0	0	0	0	0
MgCI2*2W	0	0	0	0	0	0	0	0	0
MgCk*4W	0	0	0	0	0	0	0	0	0
Mga*6W	0	0	38.427	38.427	38.427	0	38.427	0	0
Mg(0H)CI	0	0	0	0	0	0	0	0	0
Mg(0H}î	0	0	0	0	0	0	0	0	0
MgO	38.427	38.427	0	0	0	0	0	0	0

Example 5 - Process Simulation of Magnésium Ion Catalyzed Capture CO₂ from Flue Gas Using CaCl₂ to form CaCO>

Part of the defined parameters inciude the process flow diagram shown in FIG. 9. Results from the simulation suggest that it is efficient to heat a MgCl₂-6H₂O stream to form Mg(OH)Cl in a single chamber. The Mg(OH)Cl is reacted with H₂O to form MgCl₂ and Mg(OH>2· which then reacts with a saturated CaCl₂/H₂O solution and CO2 from the flue gas to form CaCO₃, which is filtered out of the stream. The resulting MgCl₂-6H₂O formed is recycled to the first reactor to begin the process again. This process is not limited to any particular source for CaCl₂· For example, it may be obtained from reacting calcium silicate with HCl to yield CaCl₂.

Constraints and parameters specified for this simulation inciude:

• The reactions were run at 100% efficiencies with no losses. The simulations can be modifîed when pilot runs détermine the reaction efficiencies.

• Simulations did not account for impurities in the CaCl₂ feed stock or in any make-up MgCJ₂ required due to losses from the system.

The results of this simulation indicate a preliminary net energy consumption of 4681 kwh/tonne CO2· Table 6 provides mass and energy accounting for the various streams of the simulated process. Each stream corresponds to the stream of FIG. 9.

The process consists of two primary reactors and one solids filtration section. The first reactor heats MgCi2.6H₂O causing it to break down into a HC1/H₂O vapor stream and a solid stream of Mg(OH)Cl. The HC1/H₂O vapor stream is sent to a heat exchanger to recover extra heat. The MgfOHh formed from the Mg(OH)Cl is sent to reactor 2 for further processing. Chemical reaction(s) occurring in this reactor inciude the following:

MgCl₂.6H₂O + Δ —> Mg(OH)Cl + 5 H₂O| + HC1| (41)

Mg(OH)Cl(aq) -> Mg(OHh + MgCl₂ (42)

A CaCl₂ solution and a flue gas stream are added to the Mg(OH)î in reactor 2. This reaction forms CaCOj, MgCl₂ and water. The CaCO₃ précipitâtes and is removed in a filter or decanter. The remaining MgCl₂ and water are recycled to the first reactor. Additional water is added to complété the water balance required by the first reactor. Chemical reaction(s) occurring in this reactor inciude the following:

Mg(OH)₂ + CaCl₂ + CO₂ -> CaCO₃ ψ($) + MgCl₂ + H₂O (43)

32539081.1

The primary feeds to this process are CaCl₂, flue gas (C0₂) and water. MgCl₂ in the system is used, reformed and recycled. The only MgCl₂ make-up required is to replace small amounts that leave the system with the CaCOj product, and small amounts that leave with the HCl/water product.

This process is a net energy user. The amount of energy is under investigation and optimization. There is cross heat exchange to recover the heat in high température streams to preheat the feed streams.

The steps for this process (Case 4) are summarized below:

CASE 4

Combined Dehydration/Decompositlon to Mg(0H)CI

Hexahydrate Is dehydrated and decomposed simultaneously at 250 *C. Reactor yields 100% Mg(OH)CI.

CO2 Absorbed	53333	MTPY
CaCI2	134574	MTPY
HCl Dry	88368	MTPY
CaCOj	105989	MTPY
Hexahydrate recycled	492737	MTPY
DEHYDRATION & DECOMPOSITION	5043	kWh/tonne CO2
TO 100% Mg(OH)CI (250 *C)
YEILDS 28.8% HCl VAPOR
	2.2	MW
Heat Recovery	361	kWh/tonne CO2
from 28% HCl vapor
TOTAL	4681	kWh/tonne CO2

52539081.1

Table 6a. Mass and Energy Accounting for Case 4 Simulation.

Process Stream Names ->	CaCk	CaCOj	FLUEGAS	H2O	HCIVAP	MgCk	MgClr6W	Mg(OH)CI1
Température °C	25	95	104	25	120	188	104	250
Pressure psia	14.7	14.7	15.78	14.7	14.696	14.7	14.7	14.696
MassVFrac	0	0	1	0	1	0	0	0
Mass SFrac	1	1	0	0	0	1	1	1
Mass Flow tonne/year	134573.943	121369.558	166332.6	234646.82	306683.742	492736.693	492736.693	186052.951
Volume Flow gal/mîn	30.929	22514	76673298	6546.44	235789.67	96.405	96.405	32.909
Enthalpy MW	-30599	-46.174	-17.479	-118.063	-98.638	-188.114	-190.147	-60.661
Density Ib/cuft	136.522	169.146	0.068	1.125	0.041	160.371	160.371	177.393
HjO	0	0	6499.971	234646.82	218315265	0	0	0
Hî	0	0	0	0	0	0	0	0
Ch	0	0	0	0	0	0	0	0
HQ	0	0	0	0	88368.477	0	0	0
CO2	0	0	53333.098	0	0	0	0	0
CO	0	0	0	0	0	0	0	0
O2	0	0	18333252	0	0	0	0	0
N2	0	0	88166278	0	0	0	0	0
CaCI2	134573.943	80.499	0	0	0	0	0	0
CafDHfe	0	0	0	0	0	0	0	0
CaCOj	0	121289.059	0	0	0	0	0	0
MgCOj	0	0	0	0	0	0	0	0
Ca(0)Cl2	0	0	0	0	0	0	0	0
MgCfe	0	0	0	0	0	0	0	0
MgCI2*W	0	0	0	0	0	0	0	0
MgCI2*2W	0	0	0	0	0	0	0	0
MgCI2*4W	0	0	0	0	0	0	0	0
MgChW	0	0	0	0	0	492736.693	492736.693	0

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Process Stream Names -»	CaCh	CaCOi	FLUEGAS	H2O	HCIVAP	MgCh	MgCWW	Mg(OH)CI1
COj	0	0	38.427	0	0	0	0	0
CO	0	0	0	0	0	0	0	0
Û2	0	0	18.168	0	0	0	0	0
Nî	0	0	99.8	0	0	0	0	0
CaCh	38.45	0.023	0	0	0	0	0	0
Ca(OH)î	0	0	0	0	0	0	0	0
CaCOa	0	38.427	0	0	0	0	0	0
MgCOs	0	0	0	0	0	0	0	0
Ca(0)Cl2	0	0	0	0	0	0	0	0
MgCh	0	0	0	0	0	0	0	0
Mgdî*W	0	0	0	0	0	0	0	0
MgCl2*2W	0	0	0	0	0	0	0	0
MgCI2*4W	0	0	0	0	0	0	0	0
MgC1/6W	0	0	0	0	0	76.854	76.854	0
Mg(OH)Q	0	0	0	0	0	0	0	76.854
Mg(0H)2 .	0	0	0	0	0	0	0	0
MgO	0	0	0	0	0	0	0	0

Table 6b. Mass and Energy Accounting for Case 4 Simulation.

Process Stream Names ->	Mg(OH)Cl2	RECYCLE1	RECYCLE2	RECYCLE3	RX2-VENT	SLURRY	VAPOR	VENT
Température’C	100	95	113.8	113.8	95	95	250	113.8
Pressure psia	14.696	14.7	14.7	14.7	14.7	14.7	14.696	14.7
MassVFrac	0	0	0.002	0	1	0	1	1
Mass SFrac	1	0.998	0.998	1	0	0.998	0	0
Mass Flow tonne/year	186052.95	493737.58	49373758	492736.69	106499.18	615107.14	306683.74	1000.89
Volume Flow gal/min	32.909	126.575	982.405	96.405	56469.408	146.834	313756.5	886
Enthalpy MW	-61.189	-190.859	-190.331	-189.91	0.241	-237.034	-96.605	-0.421

Process Stream Names ->	Mg(OH)Ch	RECYCLE1	RECYCLE2	RECYCLE3	RX2-VENT	SLURRY	VAPOR	VENT
Density Ib/cuft	177.393	122394	15.769	160.371	0.059	131.442	0.031	0.035
H2O	0	1000	1000	0	0	1000	21831527	1000
h2	0	0	0	0	0	0	0	0
Ck	0	0	0	0	0	0	0	0
HQ	0	0	0	0	0	0	88368.477	0
CO2	0	0	0	0	0.532	0	0	0
CO	0	0	0	0	0	0	0	0
O2	0	0.165	0.165	0	18333.088	0.165	0	0.165
Ni	0	0.72	0.72	0	88165.558	0.72	0	0.72
CaCh	0	0	0	0	0	80.499	0	0
Ca(OH)z	0	0	0	0	0	0	0	0
CaCOa	0	0	0	0	0	121289.06	0	0
MgCOj	0	0	0	0	0	0	0	0
CatOA	0	0	0	0	0	0	0	0
MgCh	0	0	0	0	0	0	0	0
MgCh*W	0	0	0	0	0	0	0	0
MgCh*2W	0	0	0	0	0	0	0	0
MgCh*4W	0	0	0	0	0	0	0	0
MgCl2*6W	0	492736.69	492736.69	492736.69	0	492736.69	0	0
Mg(OH)CI	18605295	0	0	0	0	0	0	0
Mg(0H)2	0	0	0	0	0	0	0	0
MgO	0	0	0	0	0	0	0	0
H2O	0	0.002	0.002	0	0	0.002	0.712	0.999
Hï	0	0	0	0	0	0	0	0
Cl2	0	0	0	0	0	0	0	0
HCl	0	0	0	0	0	0	0288	0
CO2	0	0	0	0	0	0	0	0
CO	0	0	0	0	0	0	0	0

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Process Stream Names	Mg(OH)Cli	RECYCLE1	RECYCLE2	RECYCLE3	RX2-VENT	SLURRY	VAPOR	VENT
MgCb	0	0	0	0	0	0	0	0
MgCt2*W	0	0	0	0	0	0	0	0
MgCfî*2W	0	0	0	0	0	0	0	0
MgCt2*4W	0	0	0	0	0	0	0	0
MgCV6W	0	76.854	76.854	76.854	0	76.854	0	0
Mg(OH)CI	76.854	0	0	0	0	0	0	0
MgfOHk	0	0	0	0	0	0	0	0
MgO	0	0	0	0	0	0	0	0

Example 6 - Road Sait Bolier: Décomposition of MgCh*6HiO

FIG. 10 shows a graph of the mass perccntage of a heated sample of MgC1₂*6H₂O. The sample's initial mass was approximately 70 mg and set at 100%. During the experiment, the sample’s mass was measured while it was being thermally decomposed. The température was quickly ramped up to 150’C, and then slowly increased by 0.5 ^eC per minute. At approximately 220 ^eC, the weight became constant, consistent with the formation of Mg(0H)Cl. The absence of further weight decrease indicated that almost ail the water has been removed. Two different detailed decompositional mass analyses are shown in FIGS. 28 and 29, with the theoretical plateaus of different final materials shown. FIG. 30 confirms that MgO can be made by higher températures (here, 500 ^eC) thon those which produce Mg(0H)Cl.

Example 7-Dissolution of Mg(OH)CI in H₂O

A sample of Mg(OH)CI, produced by the heated décomposition of MgCl₂*6H₂O, was dissolved în water and stirred for a period of time. Afterwards, the remaining precipitate was dried, collected and anolyzed. By the formula of décomposition, the amount of MgfOHfc could be compared to the expected amount and anolyzed. The chemical reaction can be represented as follows:

Mg(OH)Cl (aq) -> Mg(OH)₂ + MgCI₂ (44)

The solubility data for Mg(OH)₂ and MgCl₂ is ns follows: MgCI₂ 52.8 gm in 100 gm. H₂O (very soluble) Mg(0H)₂ 0.0009 gm in 100 gm. H₂O (virtually insoluble)

Theoretical weight of recovered Mg(OH)₂:

Given weight of sample: 3.0136 gm.

MW Mg(0H)Ci 76.764 MW Mg(OHh 58.32 Moles Mg(OH)₂ formed per mole Mg(OH)CI = ‘/i

Expected amount of Mg(OH)2

Mg(OH)CI (aq) -> Mg(0H)₂ + MgC1₂

3.0l6gm * (MW Mg(0H)₂ 4- (MW Mg(OH)CI * h = 1.1447 gm

Precipitate collected = I.I245 gm % of theoretical collected = (1.1447 +1.1245) ♦ 100 = 98.24%

Analytical data:

S 2539081.1

Next the sample of Mg(OHh was sent for analysis, XRD (X-ray -diffraction) and EDS. Results are shown in FIG. 11. The top row of peaks is that of the sample, the spikes in the mlddle row are the signature of Mg(0H)₂ while the spikes at the bottom are those of MgO. Thus verifying thaï the recovered precipitate from the dissolution of Mg(OH)Cl has a signa] resembling that of Mg(OH)j.

Elément	k-ratio	ZAF Atom «	Element	Wt %	Err.
(cale.	) Wt %	(1-Sigma)
Mg-K	0.9472	1.014 96.88	96.02	+/-	0.23
Si-K	0.0073	2.737 1.74	1.99	+/-	0.17
Cl-K	0.0127	1.570 1.38	2.00	+/-	0.16

Total 100.00 100.00

Note: Results do not include éléments with Z<11 (Na).

The EDS analysis reveals that very little chlorine [Cl] was incorporated into the precipitate. Note, this analysis cannot detect oxygen or hydrogen.

Exampie 8 - Decarbonatlon Bubbler Experiment: Production of CaCOj by reactlng CO₂ with Mg(OH)j (or Mg(OH)Cl] and CaCli

Approximately 20 grams of Mg(OH)2 was placed in a bubblc column with two lit ers of water and COi was bubbled though it for x minutes period of time. Afterwords some of the liquid was collected to which a solution of CaCi₂ was added. A precipitate immediately formed and was sent through the XRD and EDS. The chemical réaction can be represented as follows:

Mg(OH)₂ + CO₂ + CaCI₂ CaCOj φ + H2O (45)

The XRD analysis (FIG. 12) coïncides with the CaCOj signature.

EDS

Elément	k-ratio	ZAF	Atom %	Element	Wt % Err.
(cale. ;	) Wt %	(1-Sigma)
Mg-K	0.0070	2.211	2.52	1.55	+/- 0.10
Al-K	0.0013	1.750	0.33	0.22	+/- 0.04
Si-K	0.0006	1.382	0.12	0.09	+/- 0.03
Cl-K	0.0033	1.027	0.38	0.34	+/- 0.03
Ca-K	0.9731	1.005	96.64	97.80	+/- 0.30

Total 100.00 100.00

Note: Results do not include elemente with Z<11 (Na).

The EDS analysis indicates almost pure CaCOj with only a 1.55% by weight magnésium impurity and almost no Chlorine from the CaCI₂.

12339081.1 •

The same test was performed, except that Mg(OH)Ci from the décomposition of MgCI₂-6H₂O was used instead of Mg(OH)₂. Aithough Mg(OH)CI has half the hydroxide [0H“], as Mg(0H)₂ it is expected to absort) C0₂ and form precipltaled CaCOj (PCC).

The XRD analysis (FIG. 13) coïncides wilh lhe CaCOj signature.

EDS

Chi-sqd 5.83 Livetime = 300.0 Sec.

Standard!ess Analysis

PROZA Correction Acc.Volt.· 20 kV Take-off Angle=35.00 deg

Number of Itérations = 3

	Elément	k-ratio	ZAF	Atom %	Element	Wt %	Err.
15	(cale,	.) Wt «	(1-Sigma)
Mg-K	0.0041	2.224	1.48	0.90	+/-	0.09
	S -K	0.0011	1.071	0.14	0.11	+/-	0.04
	Ca-K	0.9074	1.003	98.30	98.98	+/-	0.34
	Total	100.00 100.00
20	Note: Results do	not ;	include	éléments	with Z<11 (Na)

Again the results indicate almost pure CaCOj, almost no Mg or Cl compounds.

Example 9A - Rock Melter Experiment: Reaction of Olivine and Serpentine with HCl ·

Samples of olivine (Mg,Fe)₂SiO4 and serpentine MgjSi₂Oj(OH)4Were crushed and 25 reacted with 6.1 molar HCl over a period of approximately 72 hours. Two sets of tests were run, the first at room température and the second at 70 C. These minerais hâve variable formulae and often contain Iran. After the samples were filtered, the resulting filtrand and filtrate were dried in an oven ovemight The samples then went through XRD and EDS analysis. The filtrâtes should hâve MgCI₂ présent and the filtrand should be primarily SiO₂.

30	Olivine Filtrate Reacted with HCl at Room Température
	Elément	k-ratio	ZAF	Atom %	Element	Wt %	Err.
	(cale.	) Wt t	(1-Sigma)
	Mg-K	0.1960	1.451	37.06	28,45	+/-	0.18
	Si-K	0.0103	1.512	1.75	1.56	+/-	0.11
35	Cl-K	0.5643	1.169	50.89	65.94	+/-	0.31
	Fe-K	0.0350	1.161	2.30	4.06	+/-	0.22

Total 100.00 100.00

Olivine Filtrate Reacted with HCl at 70 C

40	Note: Results do not include éléments with Z<11	(Na)
	Element	k-ratio	ZAF Atom %	Element	Wt %	Err.
	(cale.	) Wt %	(1-Sigma)
	Mg-K	0.1172	1.684 27.39	19.74	+/-	0.12
	Si-K	0.0101	1.459 1.77	1.48	+/-	0.07
45	Cl-K	0.5864	1.142 63.70	66.94	+/-	0.24

525390« 1.1

Fe-K 0.0990 1.144 Ni-K 0.0045 1.128 Total 100.00 100.00

6.84 11.33 +/- 0.21

0.29 0.51 +/- 0.09

Serpentine Filtrate Rencted with HCl at Room Température

ite: Results do not Include éléments with Z<11	(Na) Err.
.ement	k-ratio	ZAF	Atom %	Element	Wt %
(cale	.) Wt %	(1-Slgma)
Mg-K	0.1674	1.466	32.47	24.53	+/-	0.15
Al-K	0.0025	1.863	0.55	0.46	+/-	0.06
Sl-K	0.0033	1.456	0.55	0.48	+/-	0.04
Cl-K	0.6203	1.141	64.22	70.77	+/-	0.27
Ca-K	0.0016	1.334	0.17	0.21	+/-	0.05
Cr-K	0.0026	1.200	0.19	0.31	+/-	0.07
Mn-K	0.0011	1.200	0.08	0.14	+/-	0.08
Fe-K	0.0226	1.160	1.51	2.62	+/-	0.10
Ni-K	0.0042	1.128	0.26	0.48	+/-	0.10
Total	100.00 100.00

Serpentine Filtrate Reacted with HCl at 70°C

Note: Results do not Include éléments with Z<11 (Na)

Element	k-ratio	ZAF	Atom %	Element	Wt % Err.
(cale/	) Wt %	(1-Sigma)
Mg-K	0.1759	1.455	33.67	25.59	+/- 0.14
Al-K	0.0017	1.886	0.39	0.33	+/- 0.06
Si-K	0.0087	1.468	1.46	1.28	+/- 0.04
Cl-K	0.6014	1.152	62.46	69.27	+/- 0.25
Cr-K	0.0016	1.199	0.12	0.19	+/- 0.06
Fe-K	0.0268	1.161	1.78	3.11	+/- 0.17
Nl-K	0.0020	1.130	0.12	0.22	+/- 0.08

Total 100.00 100.00

Note: Résulta do not Include éléments with Z<11 (Na).

The filtrate clearly for both minerais serpentine and olivine at ambient conditions and 70 °C ail illustrate the presence of MgCh, and a small amount of FeClj In the case of olivine. Olivine Filtrand Reacted with HCl at Room Température

Element	k-ratlo	ZAF	Atom %	Element	Wt % Err.
(cale.	) Wt %	(1-Slgma)
Mg-K	0.2239	1.431	37.68	32.04	+/- 0.14
Si-K	0.3269	1.622	53.96	53.02	+7- 0.19
Cl-K	0.0140	1.658	1.87	2.32	+/- 0.06
Cr-K	0.0090	1.160	0.58	1.05	+/- 0.08
Mn-K	0.0013	1.195	0.08	0.16	+/- 0.09
Fe-K	0.0933	1.167	5.57	10.89	+/- 0.26
Ni-K	0.0045	1.160	0.25	0.52	+/- 0.11

Total 100.00 100.00

Olivine Filtrand Reacted with HCl at 70 °C

Elément k-ratio (cale.) Wt % Mg-K 0.2249

32339081.1

Note: Results do not include éléments with Z<11 (Na).

ZAF Atom % Element Wt % Err.

(1-Sigma)

1.461 38.87 32.86 +/- 0.16

Si-K	0.3030	1.649	51.12	49.94	+/- 0.21
Cl-K	0.0223	1.638	2.96	3.65	+/- 0.14
Ca-K	0.0033	1.220	0.29	0.41	+/- 0.05
Cr-K	0.0066	1.158	0.42	0.76	+/- 0.08
Mn-K	0.0023	1.193	0.15	0.28	+/- 0.10
Fe-K	0.0937	1.163	5.61	10.89	+/- 0.29
Ni-K	0.0074	1.158	0.42	0.86	+/· 0.13
Cu-K	0.0029	1.211	0.16	0.35	+/- 0.16
Total	100.00 100.00

Note: Results do not include éléments with Z<11 (Na).

Given that the formula for olivine is (Mg,Fe)2SiO<, and this is a magnésium rich divine. The raw compound has a Mg:Si ratio of 2:1. However the filtrand, that which does not pass through the filter has a (Mg + Fe:Si) ratio of (37+5.5:52) or 0.817:1. (Atom % on the chart), cvidently more than 50% of the magnésium passed through the filter.

Serpentine Filtrand Reacted with HCl at Room Température

ement	k-ratio	ZAF	Atom %	Element	Wt « Err.
(cale.	. ) Wt %	(1-Sigma)
Mg-K	0.1930	1.595	37.32	30.78	+/- 0.15
Si-K	0.2965	1.670	51.94	49.50	+/- 0.20
Cl-K	0.0065	1.633	0.88	1.06	+/- 0.06
Cr-K	0.0056	1.130	0.36	0.63	+/- 0.08
Fe-K	0.1532	1.155	9.33	17.69	+/- 0.31
Ni-K	0.0029	1.159	0.17	0.34	+/- 0.12
Total	100.00 100.00

Notei Results do not include éléments with Z<11 (Na).

Serpentine Filtrand Reacted with HCI at 70 °C

.ement	k-ratio	ZAF	Atom %	Element	Wt % Err.
(cale.	.) Wt %	(1-Sigma)
Mg-K	0.1812	1.536	33.53	27.83	+/- 0.13
Si-K	0.3401	1.593	56.49	54.18	+/- 0.18
Cl-K	0.0106	1.651	1.45	1.75	+/- 0.11
Cr-K	0.0037	1.142	0.24	0.43	+/- 0.07
Mn-K	0.0009	1.188	0.05	0.10	+/- 0.08
Fe-K	0.1324	1.159	8.05	15.35	+/- 0.26
Ni-K	0.0032	1.160	0.18	0.37	+/- 0.11
Total	100.00 100.00

Note: Results do not include éléments with Z<11 (Na).

Given that the formula of serpentine is (Mg,Fe)jSiîOj(OH)4 the initial 15:1 ratio of (Mg + Fe) to Si has been whittled down to (37 + 9.3:56.5) s 0.898:1.

Example 9B -Temperature/Pressure Simulation for Décomposition of

MgC12*6(H2O)

325.Ί9Ο8Ι.Ι

Pressure and température was varied, us shown below (Table 7) and in FIG. 14, to détermine the effect this has on the equilibrium of the décomposition of MgCli'âfHiO).

Inputs are:

1) MgCl_r6H₂O

2) CaCI₂

3) The température of the hot stream leaving the heat exchanger (HX) labeled Mg(0H)Cl (see FIGS. 7-8).

4) Percentage of Solids separated in decanter.

5) Water needed labeled H₂0

6) Flue Gas.

Table 7.

VARY 1	VARY 2	INPUT	Mg(OH)Cl	MgO	Q
REACT0R1	REACT0R1
PARAM	PARAM
TEM P	PRES
•c	PSIA	MOL/SEC	MOL/SEC	MOL/SEC	MW	kWh/tonna CO2
400	5	51.08399	25.31399	25.77001	23.63765	3883
410	5	38.427	0	38.427	19.85614	3261
420	5	38.427	0	38.427	19.87482	3264
430	5	38.427	0	38.427	19.89354	3260
440	5	38.427	0	38.427	19.9123	3271
450	5	38.427	0	38.427	19.93111	3274
400	7	76.854	76.854	0	3157484	5153
410	7	5354627	29.63854	23.60773	24.311B6	3993
420	7	38.427	0	38.427	19.87482	3264
430	7	38.427	0	38.427	19.89354	3268
440	7	38.427	0	38.427	19.9123	3271
450	7	38.427	0	38.427	19.93111	3274
400	9	76.854	76.854	0	31.37484	5153
410	9	72.85115	68.84829	4.002853	3050646	4961
420	9	502148	23.5756	26.6392	23.42411	3847
430	9	38.427	0	38.427	19.89354	3268
440	9	38.427	0	38.427	19.9123	3271
450	9	38.427	0	38.427	19.93111	3274
400	11	76.854	76.854	0	31.37484	5153
410	11	76.854	76.854	0	31.41	5159
420	11	64.78938	5272476	12.06462	27.81251	4568
430	11	44.67748	1250096	32.17652	21.77822	3577
440	11	38427	0	38.427	19.9123	3271
450	11	38.427	0	38.427	19.93111	3274
400	13	76.854	76.854	0	31574B4,	5153

J23390S1.I

100

VARY 1	VARY 2	INPUT	Mg(OH)CI	MgO	Q
REACTOR1	REACTOR1
PARAM	PARAM
TEMP	PRES
*C	PSIA	MOL/SEC	MOL/SEC	MOL/SEC	MW	kWh/tonne CO2
410	13	76.854	76.854	0	31.41	5159
420	13	76.854	76.854	0	31.44515	5165
430	13	55.59535	34.3367	2125865	25.07026	4118
440	13	38.427	0	38.427	19.9123	3271
4S0	13	38.427	0	38.427	19.93111	3274
400	15	76.854	76.854	0	3127484	5153
410	15	76.854	76.B54	0	31.41	5159
420	15	76.854	76.B54	0	31.44515	5165
430	15	66.51322	56.17244	10.34078	28.36229	4659
440	15	46.41875	15.98351	30.43525	22.32544	3667
450	15	38.427	0	38.427	19.93111	3274
200	5	127	76.854	0	47.51946	7805
210	5	85	76.854	0	33.34109	5476
220	5	77	76.854	0	30.74184	5049
230	5	77	76.854	0	30.77702	5055
240	5	77	76.854	0	30.8122	5061
250	5	77	78.854	0	30.B4739	5067
200	7	184	76.854	0	6657309	10935
2W	7	125	76.854	0	46.75184	7679
220	7	85	76.854	0	33.32609	5474
230	7	77	78.854	0	30.777	5055
240	7	77	76.854	0	30.81218	5061
250	7	π	76.854	0	30.84737	5067
200	9	297	76.854	0	89.51079	14702
210	9	165	76.854	0	60.16258	9882
220	9	113	76.854	0	42.92123	7050
230	9	78	76.854	0	31.04401	5099
240	9	π	76.854	0	30.B1217	5061
250	9	77	76.854	0	30.84735	5067
200	11	473	76.854	0	1365784	22433
210	11	205	76.854	0	7357332	12084
220	11	142	76.854	0	5251638	B626
230	11	98	76.854	0	38.01558	6244
240	11	ΊΊ	76.854	0	30.81216	5061
250	11	π	76.854	0	30.84734	5067
200	13	684	76.854	0	192.9858	31698
210	13	303	76.854	0	91.43505	1501B
220	13	170	76.854	0	62.11152	10202
230	13	119	76.854	0	44.98715	7309

32539081.1

101

VARY 1	VARY 2	INPUT	Mg(0H)CI	MgO	Q
REACT0R1	REACT0R1
PARAM	PARAM
TEMP	PRES
•c	PSIA	M0L/SEC	MOLÆEC	MOL/SEC	MW	kWhrtonne C02
240	13	83.3323	76.854	0	33.00459	5421
250	13	76.854	76.B54	0	30.84733	5067
200	15	930.5287	76.854	0	258.7607	42502
210	15	422.9236	76.854	0	123.7223	20322
220	15	188.7291	76.854	0	71.70666	11778
230	15	139.6567	76.854	0	51.95871	8534
240	15	98.51739	76.854	0	38.14363	6265
250	15	76.854	76.854	0	30.84733	5067

Examples 10 - 21

The following remainlng examples are concerned with obtaining the necessary heat to perform the décomposition reaction using waste heat émissions from either coal or natural gas power plants. In order to obtain the necessary heat from coal flue gas émissions, the heat source may bc located prior to the baghousc where the température ranges from 320-480 °C in lieu of the air pre-heater. See Reference: pages 11-15 of The structural design of air and gas ducts for power stations and industrial Boiter Applications, Publishen American Society of Civil Engineers (August 1995), which is incorporated by reference herein în its entirety. Open cycle natural gas plants hâve much higher exhaust températures of 600 “C. See Reference: pages 11-15 of The structural design of air and gas ducts for power stations and industrial Boiter Applications, Publisher American Society of Civil Engineers (August 1995), which is incorporated by reference herein in its entirety. Additionally, the décomposition reaction of MgCl₂-6H₂O may also run in two different modes, complété décomposition to MgO or a partial décomposition to Mg(0H)Cl. The partial décomposition to Mg(0H)CI requires in some embodiments a température greater than 180 °C whereas the total décomposition to MgO requires in some embodiments a température of 440 °C or greater.

Additionally the incoming feed to lhe process can be represented as a continuum between 100% Calcium Silicate (CaSiOj) and 100% Magnésium Silicate (MgSÎOj) with

Diopside (MgCa(SiOjh) (or a mixture of CaSiOj and MgSiOj in a 1:1 molar ratio) representing an intermediate 50% case. For each of these cases the resulting output will range in some embodiments from calcium carbonate (CaCOj) to magnésium carbonate

J2J390BM

ίο (MgCOj) with Dolomite CaMg(CO₃)₂ rcpresenting the intermediate case. The process using 100% calcium silicate is the Ca-Mg process used in ail of the previously modeled embodiments. It is also important to note that the 100% magnésium silicate process uses no calcium compounds; whereas the 100% calcium silicate incoming feed process does use magnésium compounds, but in n recycle loop, only makeup magnésium compounds are required.

Further details regarding the Ca-Mg, Mg only, Diopside processes, for example, using complété and partial décomposition of hydrated MgCI₂ to MgO and Mg(OH)Cl, respectively, are depicted below.

I) Ca-Mg Process

Overall reaction CaSiOj + CO₂ —> CaCOj + SiCh

a) Full décomposition (“the CaSiOj-MgO process’*):

1) MgCl₂.6HïO + A->MgO + 5H2Oî + 2HCIÎ

A thermal décomposition reaction.

2) 2HCl(ag) + CaSiOj -4 CaCI₂(ag) + SiO^X + HjO

A rock melting reaction.

Note 5 H₂O will be présent per 2 moles of HCl during the reaction.

3) MgO + CaClj(ag) + COa —> CaCOjl + MgCl₂(ag)

Some versions of this équation use Mg(OHh which is formed from MgO and H₂O.

4) MgCIKog) + 6HîO -> MgCI₂-6H₂O Régénération of MgCI₂.6H₂O, retum to #1.

b) Partial décomposition (“the CaSiO₃-Mg(OH)Cl process’9:

1) 2 x [MgCb etfaO + A —> Mg(OH)CI + 5H₂OÎ + HCIÎ ] Thermal décomposition.

Twice as much MgCI₂-6H₂O is needed to trop the some amount of CO₂.

2) 2HCl(ag) + CaSiO₃ -> CuCI₂(<rç) + SÎO₂l + H₂O

Rock melting reaction.

3) 2Mg(OH)Cl + CaChiaç) + CÛ2 —> CaCO₃1 + 2MgCI₂(a₉) + H₂O CO₂ capture reaction

4) 2 MgCI ₂ + 12H₂O -> 2MgCl₂-6H₂O

Régénération of MgCI₂.6H₂O, retum to #1.

32339O8I.I

103

Π) Mg Only Process

Overall reaction MgSiOj + CO₂ -» MgCOj + S1O2

c) Fui! décomposition C*the MgSiOj-MgO process)

1) 2HCl(aq) + MgSiOj + (x-l)H₂O -> MgCI₂ + SiO₂j+xH₂O Rock melting reaction.

2) MgClrxH₂O + Δ -> MgO + (x-l)H₂OÎ + 2HC1J Thermal décomposition reaction.

Note x-1 moles H₂O will be produced per 2 moles of HCl.

3) MgO +CO2-» MgCO₃ CO₂ capture reaction.

Note, in this embodiment no recycle of MgCfe is required. The value of x, the number of waters of hydration is much lower than 6 because the MgCI₂ from the rock melting reaction is hot enough to drive much of the water Into the vapor phase. Therefore the path from the rock melting runs at steady state with “x as modelcd with a value of approximately 2.

d) Partial décomposition (the MgSiOj-Mg(OH)Cl process)

1) 2HCI(aç) + MgSiOj -» MgCh + S1Ο₂1 + H₂O

Rock melting réaction.

Note x-Γ* H₂O will be présent per mole of HCl during the reaction.

2) 2 x [MgCI₂.xH2O + Δ -> Mg(OH)Cl + (x-1) Η₂Ο| + HCIfl Décomposition.

Twice as much MgCh-(x-l)H2O is needed to trap the same amount of CO₂.

3) 2Mg(OH)CI + CO2 —> MgCOjf + MgCb + H₂O CO2 capture reaction.

4) MgCl₂(ag) + 6H₂O —> Μβ0Ι₂·6Η₂Ο Regenerate MgCl₂-6H₂O, Return to #1.

Note, in this embodiment half of the MgCh is recycled. The value of x, the number of waters of hydration is somewhat lower than 6 because half of the MgCl₂ is from the rock melting reaction which is hot enough to drive much of the water into the vapor phase and the remaining half is recycled from the absorption column. Therefore the number of hydrations for the total amount of MgCh ^at steady state will hâve a value of approximately 4, being the average between the Mgd2*6H2O and MgC12'2H2O.

32339081.1

104

III) Diopside or Mixed process:

Note diopside is a mixed calcium and magnésium silicate and dolomite is a mixed calcium and magnésium carbonate.

Overall réaction: ¼ CaMg(SiO₃)i + CO₂ -+ ^ιΛ CaMg(CO₃)i + SiO₂

e) Full décomposition (“the Diopside-MgO process):

1) MgCI₂.6H₂O + Δ —> MgO + 5H₂0î + 2HCIf Thermal décomposition.

2) HCl + ½ CaMgtSIOih -> ¼ CaCb + Vi MgSiOd + H SiO₂j + H H₂O Fîrst rock melting réaction.

3) HCI + h MgSiOj -> ’ZtMgCh + ½ SÎO₂1 + 'Δ H₂O Second rock melting reaction. The MgCI₂ retums to #1.

4) MgO + W CaCI₂ + CO₂ -> W CaMg(COj) d + W MgCl₂

5) Ά MgC!₂ + 3H₂O *A MgCl₂.6H2O Regenerate MgCl₂.6H₂O, retum to #1.

f) Partial décomposition (“the Diopside-Mg(OH)Cl process):

1) 2 x [MgCl₂-6H₂O + Δ -> Mg(OH)Cl + 5HiOÎ + HC1Î ]

Thermal décomposition.

Twice as much MgC!₂*6H₂O is needed to trnp the same amount of COi.

2) HCl + CaMg(SiO₃)2 -* ½ CaCI₂ + ¼ MgSiOd + ¼ SiOd + W H₂O First rock melting reaction.

3) HCl + Vi MgSiO₃ -♦ WMgCli + !ô SÎO₂j + K H₂O

Second rock melting reaction. Here the MgCh retums to #1.

4) 2Mg(OH)Cl + ¼ CaCI₂ + CO₂ -> W CaMg(CO₃) il + 3/2 MgCh +

HiO

5) 3/2 MgCli + 9H₂O -> 3/2 MgC!r6H₂O

Regenerate MgClr6H₂O, retum to #1

323.19C8I.1

Table 9. Snmmary oT Processes

Example	Process	Flue gas source	Temp. °C'	% COî of flue gas2	Detailed mass and energy balance of each process stream
10	CaSiOj-Mg(OH)Cl	Coal	320-550	7.2%-18%	Table 14
11	CaSiOj-Mg(OH)Cl	Nat gas	600	7.2%-18%	Table 14
12	CaSiOj-MgO	Coal	550	72%-18%	Table 15
13	CaSiOj-MgO	Nat gas	600	7.2%-18%	Table 15
14	MgSiOa-MgiOHJCl	Coal	320-550	72%-18%	Table 16
15	MgSiOrMg(OH)Cl	NaL gas	600	72%-18%	Table 16
16	MgSiOj-MgO	Coal	550	72% -18%	Table 17
17	MgSiOj-MgO	NaL gas	600	72% -18%	Table 17
18	Diopside-Mg(OH)Cl	Coal	320-550	72%-18%	Table 18
19	Diopside-Mg(OH)Cl	NaL gas	600	72%-18%	Table 18
20	Diopside-MgO	Coal	550	7.2%-18%	Table 19
21	Diopside-MgO	NaL gas	600	72%-18%	Table 19

- The température range of 320-550 “C includes models nm at 320,360,400,440 and 550 ’C respectively.

2—The COj percentage of flue gas 7.2% -18% indudes models run at 72%, 10%, 14% and 18% respectively.

Calcium Silicate process:

The CaSiOj-MgO and CaSiOj-Mg(OH)Cl décomposition processes are further divided into two stages, the first step consists of a déhydration reaction where MgCl₂-6H₂O is converted to MgCl₂-2H₂O + 4 H₂0 and the second step in which the MgCl₂-2H₂O is 5 converted to Mg(OH)CI 4- HCl 4- H₂0 if partial décomposition is desired or required and MgO 4- 2HC14- H₂0 if total décomposition is desired or required. FIG. 15 describcs a layout of this process.

Magnésium Silicate process:

The MgSïOj-MgO and MgSïO3-Mg(OH)Ci processes consists of a one chamber i 0 décomposition step in which the HCl from the décomposition chamber reacts with MgSiOj in the rock-melting reactor and the ensuîng heat of reaction ieaves the MgCI₂ in the dihydrate form MgCir2H₂O as it Ieaves the rock-melting chamber în approach to the décomposition reactor where it Is converted to either MgO or Mg(0H)CI as described eariier. This process may be preferred If calcium silicates are unavailable. The HCl emîtted from the 15 décomposition reacts with MgSiOj to form more MgCl₂. The magnésium silicate process follows a different path from the calcium. The process starts from the “rock melting reaction HCi 4- silicate, and then moves to the décomposition reaction (MgCl₂ 4- heat),” and lostly the absorption column. In the calcium silicate process, ali the magnésium compounds rotate between the décomposition reaction and the absorption reaction. FIG. 16 describes the layout 20 of this process.

Mixed Magnésium and Calcium Silicate “Diopside” process:

The Intermediate process Diopside-MgO and Diopside-Mg(OH)Cl also involve a two stage décomposition consisting of the déhydration réaction MgCI₂*6H₂O 4- Δ -4 MgCl₂‘2H₂O 4- 4 H₂O followed by the décomposition reaction MgCl₂-2H₂O 4- Δ —> MgO 4- 2HCI 4- H₂O 25 (full décomposition) or MgCI₂-2H₂O + Δ -4 Mg(OH)CI 4- HCl 4- H₂O partial décomposition.

FIG. 17 describes a layout of this process.

The ensuing HCl from the décomposition then reacts with the Diopside CaMgfSiOj^ in a two step rock melting réaction. The first reaction créâtes CaC1₂ through the reaction 2HCI4- CaMgtSiOjh -* CaCl₂(aç) 4- MgSiOjl+ SiO₂j 4- H₂O. The solids from the prevîous 30 réaction are then reacted with HCl a second time to produce MgCl₂ through the reaction MgSiOj 4- 2HCI -♦ MgCh + SiO₂I+H₂O. The CaCi₂ from the first rock melter is transparted to the absorption column and the MgCI₂ from the second rock melter is transported to the décomposition reactor to make Mg(OH)CI or MgO.

32339O8I.I

107

Basis of the reaction:

Ail of these examples assume 50% CO₂ absorption of a reference flue gas from a known coal fired plant of interest. This was done to enable a comparison between each example. The émission flow rate of flue gas from this plant is 136,903,680 tons per year and 5 lhe CÛ2 content of this gas is 10% by weight. This amount of CO₂ is the basis for examples 10 through 21 which is:

Amount of CO₂ présent in the flue gas per year 136,903,680 tons per year * 10% “ 13,690368 tons per year

Amount of CO₂ absorbed per year.

13,690,368 tons per year * 50% = 6,845,184 tons per year of CO₂.

Since the amount of CO₂ absorbed is a constant, the consumption of reactants and génération of products is also a constant depending on lhe réaction stoichiometry and molecuiar weight for each compound.

For ali the exemples of both the CaSiOj-MgO and lhe CaSÎO₃-Mg(OH)Cl process 15 (exemples 10-13) the overall reaction is:

CaSiOj + CO₂ —> CaCO₃ + SiO₂

For ail the examples of both the MgSiO₃-MgO and the MgSiOj-Mg(OH)CI process (examples 14-17) the overall réaction is:

MgSiO₃ + CO₂ —> MgCOj + SiO₂

For ail the examples of both the Diopside-MgO and the Diopside-Mg(OH)Cl process (exemples 18-21) the overall reaction is:

¼ CaMg(SiO₃)₂+ CO₂ 'Λ CaMg(CO₃)r+ SiO₂

The Aspen mode! entera the required inputs for the process and calculâtes the required flue gas to provide the heat nceded for the décomposition reaction to producc the carbon 25 dioxide absorbing compounds MgO, Mg(OH)2 or Mg(OH)CI. This flue gas may be from a naturel gas or a coal plant and in the case of coal was tested at a range of températures from 320 °C to 550 ^eC. This flue gas should not be confused with the référence flue gas which was used a standard to provide a spécifie amount of CO₂ removal for each examplc. A process with a higher température flue gas would typicaliy require a lesser amount of flue gas 30 to capture the same amount of carbon dioxide from the basis. Also a flue gas with a greater carbon dioxide concentration would typicaliy resuit in greater amount of flue gas needed to capture the carbon dioxide because there is a greater amount of carbon dioxide that needs to be captured.

51539081.1

108

The consumption of reactants and génération of products can be determined from the

basis of CO2 capturcd and the molecular example. Table 10. Molecular Masses of Inputs an<	heights of each input and each output for each 1 Outputs (ail embodiments).
Compound	. Molecular Weight
CaSiOj	I 116.16
MgSiOj	I 99.69
Diopside*	I 215.85
CaCOj	1 100.09
MgCOj	1 84.31
Dolomite*	I 184.40
SiO2	| 60.08
CO2 ·	1 44.01
* Number of moles must be divided by 2 other processes, For Examples 10-13: The CaSiOj consumption is:	to measure comparable CO2 absorption with the

6,845,184 tons per year * (116.16 /44.01) = 18,066,577 tons per year. The CaCO₃ production is:

ιο

6,845,184 tons per year * (100.09/44.01)= 15,559,282 tons per year. The SiO₂ production is:

6,845,184 tons per year * (60.08/44.01) = 9,344,884 tons per year

The same type of calculations may be done for the remaining examples.

This following table contains the inputs and outputs for examples 10 through 21. Basis: 6,845,184 tons CO2 absorbed per year.

Table 11. Mass Flows oflaputs and Outputs for Examples 10-21,

- Al! measurements are in tons per year (TPY)
	{ Examples
	10-13	14-17	18-21
CO2 absorbed	6,845,184	6,845,184	6,845,184
	1

109

AU measurements are in tons per year (TPY)
	1 Examples
	10-13	14-17	18-21
INPUTS	|
Flue Gas for CO2 Capture	136,903,680	136,903,680	136,903,680
10% CO2	13,690,368	13,690368	13,690368
CaSiOj	18,066,577
MgSiOj	1	15,613,410
Diopside			16,839,993
	|
OUTPUTS	I
SiO2	9,344,884	9344,884	9,344,884
CaCOj	15,559,282
MgCOj	|	13,111,817
Dolomite	1		14319,845

Running the Aspen models generated the following results for the heat duty for each step of the décomposition reaction, déhydration and décomposition. The results for each example are summarized in the table below.

Table 12. Power (Rate of Energy for each process at the particular basis of COj absorption).

Diop.- MgO

IZ*OZ

1306

1374

o

2680

ο o b|

wM 00 wM

* SD n

1231

o *4 fM

3854

1 OO

r* vc

i

lin g with silicate

3 fM

S

14,15

·§

1226

o VH fM

a 0 v 9 E

so »

έ 3

12,13

1087

g G te

1297

« G G

3 ?

2384

0 B o o* 3

10,11

2670

1033

c * c

3 •4

3703

HEAT BALANCE

Process

Examnles

Déhydration Chamber (MW)

G G O W Cl M Q O H

Source

Décomposition Chamber(MW)

C Q 1 < F F

J i 5 u M S D 3 3 g i

Source

Total beat used for D&D* (MW)

110

Table 13. Percentage COz captnred as a function of flue gas température and COj concentration. Examples 10 through 13.

2 M ss	NaLgas 600 °C	13		s	69%	£ s	s Ch m
0 cSêb	Su Mo U S Z §			£ CM pM	£ So	£ CM Ό	iS 3
50	u 0 SÏ n 3	CM *>4		£ £3	1	m <r	tf! m m
□ e 0 o1 3	So u « w»	0 *•4		£ in 0	£ P	£ V)	£ M
- u s 0	0		£ 0 r-	£ s	£ Ό <*»	£ 00 CM
rs U g ° os xr	0		£	£	g CM	£
	0		£	£ CM m	£ a	£ 00
•a to	0		£ m m	£ ’t CM	£ £	£ m
Process	Flue Gas Source/Temp.	* JL· a. § £	g	r*	0	$ xr w	£ 00

m m

Table 14. Percentage COj captured as a function of flue gas température and CO₂ concentration. Examples 14 through 17.

êo	U O sa z:	Γ*		tR «	tR Ch KD	tR Dk	38%--
J,O ii h	U o a z:	m		tR s	tR S	tR 00 tT	tR C'en
<So F	u o m	KO *·		tR KO 00	tR CN KO	tR 5	tR S
□ B o c? i	U © •n δ			tR 00	£ KO	(R	éR S 1
U O O a o U			tR m V)	&	£ 00 <N	tR CN CN
CJ 0	Tp w		tR m Tt·	tR CN m	£ n	tR oo
© $ n	M		§ en	tR «	tR 00	tR ·*
- U « O δ §			£ S	tR c-	tR CN	tR o *·
Process	ri. a § Ü H «t jJ 9 P El m	* V Ξ.	β IR	£ f-	£ c WH	iR	tR 00 WH

112

Table 15. Percentage C0₂ captured as a fonction of fine gas température and CO₂ concentration. Exemples 18 through 21.

O f a Q. O • M G	3·° £|	21		91%	£ S	47%	36%
° o		o		£ WM O WM	(P m r*	£ d m	(P WM
o s • ex o G	-, W S ° Λ ° U w) tf)			£ o r-~	£ ln	£ ?	£ WM m
□ g 4 •s § ··* G	·§ -3 8	00 M		(P CO CO	£ m Ό	(P m 'T	£ •n n
•| ?	00 rH		σ\ *n	(P d 'T	£ o n	£
•a S*	CO		£ 00 'T	£ •n m	£ »	tP O\
a ? c3S m	00		(P 00 m	(P ïs	£ Oi WM	£ »n M
_ U s °	00 WM		£ 00 d	£	tfi 'T WM	£ WM -
Process	Flue Gas Source/Temp.	40 u 7x E ώ	ë £	£ r-	e WM	£ •V WM	(P 00

U3 •n

Table 16a. Mass and Energy Accounting for Exaniples 10 and 11 Simulation.

HC! Vapor

S

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8

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HCIVapor

o

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HCl 1

o

o

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FLUEGAS

o

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5.65E+06

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SOLIDS-2		1 ns 1	xr	in co	to	2 s ci	§ Ul 8 <d
SOUDS-1		g	xr	o	-	§ co cJ	I
SLURRY	co in φ»· CT	æ	Φί*	o	K	§ i? CT	g e xr a
d «		CT	8	o	-	8.47E+06	<0 1
RX2-VENT		æ	r*	-	o	1 in	1 CM
RECYCLE1	Ώ xr CT	$	r-	o	o	! i	33789.492
β CT S		s	<0 $ xr	o	-	R in	11216.796
1 SE		m CM	§	§	CO CT	1 f? in	1 8 CO
Process Stream Naines ->	£	o e € 1 £	| Pressure pria	o s £ s	| Mass SFrac	MassHow tonne/ÿear	C 1 Φ 1

115

SOUDS-2

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Process Stream Names

& i]

Density b/tuft

2

g

d

Z

1 2

1 2

1 2

δ 2

O es s

w 2

2

2

g

i

& 2

â

6

g

116 +695» ΒΒβη

SOUDS-2	o	o	o	o
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DIOPSIDE

| DOLOMITE

133

Example 22: Décomposition of other salts.

The thermal décomposition of other salts has been measured in lab. A summary of some test results are shown in the table below.

Table 22. Décomposition ofother salts.

Sait	Temp.’C	Time (min.)	| Results
MgiNOjh	400	30	63% décomposition. Reaction is Mg(NO3)2 —* MgO + ! 2NO2+'/i o2
MgiNOjh	400	45	| 64% décomposition.
MgiNOjh	400	90	| 100% décomposition
MgiNOjh	400	135	| 100% décomposition
Ca(NOj)2	400	30	<25% décomposition Reaction is Ca(NOj)2 —♦ CaO + | 2NOï+ViO2
CaiNOjh	600	50	1 61% décomposition
CaiNOjfc	600	Ovemight	| 100% décomposition
LiCl	450	120	| -0% décomposition

Exampie 22: Two, Three and Four-Chamber Décomposition Models

Table 23 (see below) is a comparison of the four configurations corresponding to FIGS. 31 -34. Depicted are the number and description of the chambers, the heat consumed in MW (Mégawatts), the percentage of heat from that particular source and the réduction of required extemal beat in kW-H/tonne of C0₂'because of available heat from other reactions 10 în the process, namely the hydrochloric acid reaction with minerai silicates and the condensation of hydrochloric add. In the FIG. 34 exemple, the hot flue gas from the opencycle naturel gas plant also qualifies.

Examine 23: Output Minerai Compared with Input Minerais—Coal

In this case study involving flue gas from a coal-based power plant. Table 24 i illustrâtes that the volume of minerai outputs (limestone and sand) are 83% of the volume of input minerais (coal and inosilicate). The results summarized in Table 24 are based on a 600 MWe coal plant; total 4.66 E6 tonne CO_2t includes CO₂ for process-required beat.

Example 24: Output Minerai Compared with Input Minerais—Naturel

Gas

In this case study summarized in Table 25 (below) Involvïng flue gas from a natural gas-based power plant, the rail-back volume of minerais is 92% of the rail-in volume of 5 minerais. The results summarized in Table 25 are (based on a 600 MWe CC natural gas plant; total 2.41 E6 tonne CO₂, which includes CO2 for process-required heat

Table 23. Two, Three and Fonr-Chamber Décomposition Results

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Table 24. Coal Scénario—Volume of Minerai Outputs Compared with Volume of Minerai Inpnts

Engllsh Units	« Έ fg > °	s SO	611.8	s M 00 SO			0\ ri RM	*ri T?	565.4	83.00%
8Î S £	R rm	SO *n m rm			1	D0 «© rM RM	8 r-	00 so te	RATIO OF MINERAL VOLUME OUT/MINERAL VOLUME IN =>
2 g Έ S		§	n P RM				D0 RM RM	R τ	RM o RM
Mass (10* Tonne/yr)	5	O a rm				3 e> RM	«n «Ί so	0S vd RM
	Bulk Density (Tonnehn3)	00 o	p o				Ch Ci	Ό RM	s
b X 1	§	ô 3	5 WH 3 + *s o			ê a	<5 • M W	<5 K + § a

137

Table 25. Naturel Gas Scénario — Volume of Minerai Outputs Compared with Volume of Minerai Inputs

a a P	*J t, E<? 1¾ o* > S	2 O\ tO	611.8	« FM CO to			415.9	Ό Ch M·	565.4	83.00%
ω	£										n
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Έ g	Mass (10* Toune/yr)		o a			8 d	«n n «3	in σχ d	O O i
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138

Example 25: Sélective production οΓ magnésium hydroxide by , disproportionation of water and magnésium chloride

Mg(0H)₂ can be used in the following reaction to produce limestone from CO₂ gas. CaCI₂(aq) + COz + Mg(0H)₂ => MgCI₂(aq) + CaCOjl+ H₂O

In order to optimize production of MgfOHh. upon conversion of MgCl₂ to

Mg(0H)Cl, the amount of water in the reaction chamber will be adjusted to favor MgÇOHh précipitation. Specifically, when Mg(0H)Cl and MgCl₂ is provided in a large enough volume of water, the magnésium hydroxide précipitâtes, as it is virtually insoluble, whereas the magnésium chloride forms an aqueous solution. Thus the two compounds may be efficiently 10 separated. Note the water (H₂O) in the reaction below, does not become part of the products, it merely solvatés the Mg²* and Cl* so they become an ionic solution.

Mg(0H)CI (H₂O) => ¼ Mg(0H)4+ là MgCl₂(aq)

If the amount of water Is reduced until the a ratio of about 6 to I relative to magnésium, it would be possible to form MgCl₂-6H₂O instead of MgCl₂(aq). The équation 15 would be as follows:

Mg(0H)CI + 3H₂O => ½ Mg(0H)4+ Ά MgCl₂.6H₂O

Thus, by maintaining a MgCl₂ to water ratio of greater than or equal to 6 to l, production of aqueous MgCl₂ and solid Mg(0H)i is favored. Thus, an example set of CO2 capture reactions can be represented as:

i) MgCl₂H₂O => Mg(OH)CL + H₂O + HCl ii) HCl + CaSiOj => CaCI₂ + H₂O + SiO₂ i») Mg(0H)CI + MgCl₂ + H₂O => MgCOHfc + MgCl₂ + H₂O iv) H₂O + Mg(0H)₂ + CO₂ + CaCl₂ => MgCl₂ + CaCOj + H₂O

I

With an overall reaction of: CaSiO₂ CO₂ => CaCOj + SiO₂.

This system is shown in the the Aspen diagram of FIO. 38A-I and FIO. 39A-I. The outlined rectangle in the center of the diagram is around the defined “water disproportionator”. At (lie top of the rectangle, Mg(OH)CI, stream SOLIDS-Ι, is leaving the décomposition reactor labcled DECOMP”. Then in the module labeled MG0H2, the Mg(0H)Ci is mixed the aqueous MgCI₂ from the absorption column, stream RECYCLE2.

They leave as a slurry from the unit as stream “4”, pass through a heat exchanger and send heat to the décomposition chamber. The stream is then named “13“ which passes through a séparation unit which séparâtes the stream into stream MGCLSLRY (MgCI₂.6H₂O almost) and stream SOLIDS-2, which is the Mg(0H)₂ heading to the absorption column.

140 ****************

Ail of lhe methods disclosed and claimed herein can be made and executed without undue expérimentation in light of the présent disclosure. While lhe compositions and melhods of Ihis invention hâve been described in terms of particular embodiments, it will be 5 apparent to those of skill in lhe art that variations may be applied to lhe melhods and in lhe i

steps or in the sequence of steps of the method described herein without departing from lhe concept, spirit and scope of the invention, | AU such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appendcd daims.

REFERENCES

The following référencés, to the extent that they provicie exemplary procédural or other details supplcmentary to those set forth herein, are specifically incorporated herein by reference.

U.S. Prov. Appln. 60/612,355 U.S. Prov. Appln. 60/642,698 U .S. Prov. Appln. 60/718,906 U.S. Prov. Appln. 60/973,948 U.S. Prov. Appln. 61/032,802 U.S. Prov. Appln. 61/033,298 U.S. Prov. Appln. 61/288,242 U.S. Prov. Appln. 61/362.607 U.S. Patent Appln. 11/233309 U.S. Patent Appln. 12/235.482 U.S. Patent Pubn. 2006/0185985 U.S. Patent Pubn. 2009/0127127 U.S. Patent 7.727374

PCT Appln. PCT/US08/77122

Goldberg et al., Proceedings of First National

Conférence on Carbon Séquestration, 14-17

May 2001, Washington, DC., section 6c,United States Départaient of Energy, National Energy Technology Laboratory. available at*. http://www.netl.doe.gOv/publications/proceedings/0 l/carbon_seq/6c 1 .pdf. Proceedings of First National Conférence on Carbon Séquestration, 14-17 May 2001,

Washington, DC. United States Department of Energy, National Energy Technology Laboratory. CD-ROM USDOE/NETL-2001/1144; also available at http://www.nctl.doe.gov/publications/proceedings/01/carbon_seq/carbon_seq01.html. de Bakker, The Recovery of Magnésium Oxide and Hydrogen Chloride from Magnésium

Chloride Brines and Molten Sait Hydrates, March 2011, Queens University, Kingston, Ontario, Canada. Thésis by Jan Simon Chrisliaan de Bakker; also available on the internet at qspace.library.quecnsu.ca/bitstream/1974/6337/l/de%20BakkcrJan_S_C_201103_P hD.pdf.

*

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Claims (42)

1. WHATJS CLAIMED IS;

   1.

   A method of sequestering carbon diox de produced by a source, comprising:

   (a) reacting MgCI₂ or a hydrate thereof with water in a first admixture under conditions suitabie to form u first product mixture comprising a first step (a) i

   product comprising Mg(OH)CI and a second step (a) product comprising HCl;

   (b) rcactîng some or al! of the Mg(OH)Cl from step (a) with a quantity of water and a quantity of MgCl₂ in a second admixture under conditions suitabie to form a second product mixture comprising a first step (b) product comprising Mg(OHh and a second step (b) product comprising MgCli, wherein the quantity of water is sufficient to provide a molar ratio of water to MgCI₂ of greater than or equal to 6 to 1 in the second product mixture;

   (c) admixing some or ail of lhe Mg(OH)₂ from lhe first step (b) product with CaCl₂ or a hydrate thereof and carbon dioxide produced by the source in a third admixture under conditions suitabie to form a third product mixture comprising a first step (c) product comprising MgCl₂ or a hydrate thereof, a second step (c) product comprising CaCOj, and a third step (c) product eomprising water; and (d) separating some or ail of lhe CaCOj from the third product mixture.

   whereby some or ail of lhe carbon dioxide is sequestered ns CaCOj.
2. 2. The method of claim 1, wherein some or ail of the water in step (a) is présent in the form of a hydrate of lhe MgClj.
3. 3. Tlie method according to either claims 1 or 2, wherein the molar ratio of water to MgCI₂ in lhe second product mixture is between 6 and 10.
4. 4. The method of claim 3, wherein the molar ratio of water to MgCI₂ in the second product mixture is between about 6 and about 7.

   The method according to any one of c
5. 5.
6. 6.

   aims 1-4, further comprising monitoring lhe concentration of Mg in the second admixture.

   The method of claim 5, wherein the amount of Mg(OH)CI or the quantity of water In a second admixture is adjusted based on said monitoring.

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7. 7. The melhod according to any one of claims 1-6, wherein the MgCl₂ of step (a) is a

   MgCI₂ hydrate. j
8. 8. The melhod of claim 7, wherein the MgCl₂ hydrate of step (a) is MgCl₂*6H₂O.
9. 9. The melhod according to any one of claims 1-8, wherein lhe MgCI₂ of step (a) is greater than 90% by weight MgCI₂-6(H₂O).
10. 10. The method according to any one of claims 1-9, wherein the first step (a) product comprises greater than 90% by weight Mg(0H)CI.
11. 11. The melhod according to any one of claims 1-10, further comprising separating lhe step (b) products.
12. 12. The method of claim 11, wherein the Mg(0H)₂ product of step (b) is a solid and wherein separating lhe step (b) products comprises separating some or ail of lhe solid ι

    Mg(OHh from the water and the MgCi₂.
13. 13. The melhod according to any one of claims 1-12, wherein the MgCI₂ product of step (b) is aqueous MgCl₂.
14. 14. The melhod according to any one of c aims 1-13, wherein some or ail of lhe MgCl₂ formed in step (b) or step (c) is the MgCl₂ used in step (a).
15. 15. The method according to any one of claims 1-13, where some or ail of the water in step (a) is présent in the form of steam or supercriticai water.
16. 16. The method according to any one of claims 1-15, where some or ail of lhe water of step (n) is obtained from lhe water of step (c).
17. 17. The method of any one of claims 1-16, further comprising:

    (e) admixing a calcium silicate minerai wilh HCl under conditions suitable to form n third product mixture comprising CaCi₂, water, and silicon dioxide.
18. 18. The melhod of ciaim 17, where some or ail of lhe HCl in step (e) is obtained from step (a).
19. 19. The method of claim 17, wherein step (e) further comprises agitating the calcium silicate minerai wilh HCl.

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20. 20. The method according to any one of claims 17-19, wherein some or ail of the heat generated in step (e) Is recovered.
21. 21. The method according to any one of claims 17-20, where some or ail of the CaCl₂ of step (c) Is the CnCl₂ of step (e).
22. 22. The method according to any one of claims 17-21, further comprising n séparation step, wherein the silicon dioxide is removed from the CaCI₂ formed in step (e).
23. 23. The method according to any one of claims 17-22, where some or ail of the water of step (a) is obtained from the water of step (e).
24. 24. The method according to any one of daims 17-22, wherein the calcium silicate minerai of step (e) comprises a calcium inosïlicate.
25. 25. The method according to any one of claims 17-22, wherein the calcium silicate minerai of step (e) comprises CaSiOj.
26. 26. The method according to any one of claims 17-22, wherein the calcium silicate minerai of step (e) Ca₂Mgj{[OH]Si4Oti}₂.

    comprises diopside (CaMg[Si₂O_eJ) or tremolitc
27. 27. The method according to any one of daims 17-22, wherein the calcium silicate further comprises iron and or manganèse silicates.
28. 28. The method of claim 27, wherein the iron silicate is fayalite (Fe₂[SiOj])·
29. 29. The method according to any one of claims 1-28, wherein the carbon dioxide is in the form of flue gas, wherein the flue gas ftirther comprises N₂ and H₂O.
30. 30. The method according to any one of claims 1-29, wherein suitable reacting conditions of step (a) comprise a température from about 200 °C to about 500 “C.
31. 31. The method of claim 30, wherein the température is from about 230 °C to about 260 °a
32. 32. The method of claim 30, wherein the température is nbout 250 °C.
33. 33. The method of claim 30, wherein the température is from about 200 ^eC to nbout 250 °C.

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34. 34. The method of claim 30, wherein lhe température is about 240 “C.
35. 35. The method according to any one of daims 1-34, wherein lhe suitable reacting conditions of step (b) comprise a température from about 140 °C to about 240 °C.
36. 36. The method according to any one of claims 1-35, wherein suitable reacling conditions

    5. of step (c) comprise a température from about 20 ^eC to about 100 °C.
37. 37. The method of claim 36, wherein lhe température is from about 25 ^eC to about 95 °C.
38. 38. The method according to any one of claims 17-37, wherein suitable reacting conditions of stcp (e) comprise a température from about 50 °C lo about 200 °C.
39. 39.

    The method of claim 38, wherein the température is from about 90 °C to about 150 “C.
40. 40. The method according to any one of claims 1-39, wherein some or aJl of lhe hydrogen chloride of step (a) is admixed with water to form hydrochloric acid.
41. 41. The method of claim 1, wherein step (a) occurs in one, two or three reactors.

    i
42. 42. The method of claim 1, wherein step (a) occurs in one reactor.