KR20160063266A - Oxygen carrier particle for preparing hydrogen, and method for activating the same - Google Patents
Oxygen carrier particle for preparing hydrogen, and method for activating the same Download PDFInfo
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- KR20160063266A KR20160063266A KR1020150165365A KR20150165365A KR20160063266A KR 20160063266 A KR20160063266 A KR 20160063266A KR 1020150165365 A KR1020150165365 A KR 1020150165365A KR 20150165365 A KR20150165365 A KR 20150165365A KR 20160063266 A KR20160063266 A KR 20160063266A
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
- C01B13/14—Methods for preparing oxides or hydroxides in general
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
- B01J2/02—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by dividing the liquid material into drops, e.g. by spraying, and solidifying the drops
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
- C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
- C01B3/06—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents
- C01B3/10—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents by reaction of water vapour with metals
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- C01F17/0043—
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G41/00—Compounds of tungsten
- C01G41/02—Oxides; Hydroxides
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/02—Oxides; Hydroxides
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/32—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid using a mixture of gaseous fuel and pure oxygen or oxygen-enriched air
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
Abstract
Description
The present invention relates to an oxygen donor particle for hydrogen production, and a method of activating the oxygen donor particle. More particularly, the present invention relates to a raw material composition constituting oxygen donor particles for hydrogen production, oxygen donor particles containing the oxygen donor particles, .
The use of advanced fossil fuels along with the development of civilization has a great influence on the greenhouse effect that raises the temperature of the earth, so that the average temperature of the earth rises and the damage of climate change is continuously appearing.
The world's largest producer of hydrogen is the world's largest consumer of hydrogen and petrochemical processes to own a hydrogen production plant to meet a large amount of hydrogen demand, to recover the by-product hydrogen, or to cover the internally produced hydrogen deficit In fact, demand from the industry is increasing.
At present, more than 80% of world's hydrogen production is produced through steam-methane reforming (SMR) process. Therefore, the efficiency of CO 2 capture technology and carbon capture and storage (CCS) should be accompanied and hydrogen demand is continuously increasing.
CCS technology can be directly cut into the mass emission of CO 2 culprit of global warming, the United Nations Intergovernmental Panel on Climate Change (IPCC) apply the reporting CCS technologies to the world's CO 2 amount to the next in 2100 at least 15% It can be reduced by up to 55%.
However, when the CCS technology is applied to a power plant for power generation, the power generation efficiency is reduced and the cost of the power generation is increased.
The IGCC (Coal Gasification Combined Cycle) plant is applied to CCS technology for hydrogen production, but the process is complicated due to the combination of CO 2 absorption technology including water gas conversion (WGS), pollution gas purification technology, . Currently, Selexol CO 2 capture technology, which is widely used, has high operating cost due to gas compression, complex process, operation and high electricity consumption, accounting for about 70 ~ 80% of CCS cost.
Chemical looping (CL) technology is attracting attention as a technology capable of source separation of CO 2 without deteriorating power generation efficiency. The above-mentioned media circulation combustion technology burns fuel with oxygen contained in metal oxide instead of air, so that only the water vapor and CO 2 are contained in the gas discharged after the combustion of the fuel. Therefore, when condensate is removed from only the steam in the exhaust gas, only CO 2 is left, so CO 2 source separation is possible. The medium circulation combustion technology uses oxygen donor particles as an oxygen delivery medium. In the medium circulation combustion process, a fluidized bed reactor (reduction reactor) in which oxygen contained in the oxygen donor particles is transferred to the fuel and a reaction in which the oxygen donor particles are reduced, and a reduced oxygen donor particle, (oxidation reactor) in which the oxidation reaction takes place in a fluidized bed reactor.
The technology of chemical looping for H 2 production (CLH 2 ) in the media circulation process has been attracting attention as a technology capable of separating CO 2 without reducing the hydrogen production efficiency. A circulating moving-bed process is adopted to maximize combustion efficiency and hydrogen production efficiency.
Such oxygen donor particles must satisfy various conditions suitable for circulating process characteristics. It is desirable to have sufficient strength, shape suitable for flow, packing density or tapped density, average particle size, particle size distribution, and pore structure favorable to diffusion of reaction gas. It also has a high oxygen transfer capacity in terms of reactivity, so that it must be able to supply enough oxygen for fuel to pass through the fuel reactor as it passes through the fuel reactor.
Generally, oxygen donor particles are composed of a metal oxide and a carrier, which are active materials. Here, the support serves to increase the dispersion of the metal oxide, to impart strength to the particles, and to suppress sintering of metal oxides that may occur during the circulation of the media. That is, depending on the type of the carrier, the reactivity and physical properties of the finally prepared oxygen donor particles are different.
Conventionally, oxygen donor particles using zirconia (ZrO 2 ) as a carrier raw material of Fe 2 O 3 active material have been proposed. The oxygen donor particles prepared using the zirconia have high strength and are chemically stable. When the spray-formed particles are sintered at a high temperature of 1,300 ° C or more to obtain the strength necessary for the application of the circulating process, the packing density of the particles after sintering is high, so that more energy is consumed for fluidization and sintering is caused by high temperature sintering Which results in a problem of lowering the oxygen transfer capability. Further, there is a problem that the firing cost due to high-temperature firing also increases.
Therefore, there is a need for an oxygen donor particle production method capable of securing sufficient strength required in the circulation process while lowering the firing temperature in order to improve the oxygen transfer capacity of the oxygen donor particles and to reduce the particle production cost due to the high temperature firing of the oxygen donor particles It is true.
DISCLOSURE OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a process for producing oxygen donor particles, The present invention provides a method of activating oxygen donor particles and oxygen donor particles which are manufactured at a relatively low sintering temperature as compared with the prior art through an optimal activation process and which have excellent strength and oxygen transfer capability and have physical properties suitable for a circulation process .
According to an aspect of the present invention, there is provided a metal oxide-containing composition comprising 100 parts by weight of an active material comprising a metal oxide; 20 to 400 parts by weight of a carrier; And a binder comprising 1 or more selected from calcium oxide (CaO), hafnium oxide (HfO 2 ), lanthanum oxide (La 2 O 3 ), magnesium oxide (MgO) and boron oxide (B 2 O 3 ) By weight of an oxygen donor particle.
The binder may include at least one selected from calcium oxide (CaO), magnesium oxide (MgO) and boron oxide (B 2 O 3 ).
The binder may include 5 to 500 parts by weight of magnesium oxide and 10 to 600 parts by weight of boron oxide, based on 10 to 100 parts by weight of calcium oxide.
The metal oxide contained in the active material may include iron oxides (FeO, Fe 2 O 3, Fe 3 O 4), tungsten oxide (WO 2, WO 3), and ceria (CeO 2) at least one selected from.
Wherein the support is selected from the group consisting of AlO 3 , ZrO 2 , Y 2 O 3 , CeO 2 , La 2 O 3 , MgO, SrO 2, ), Calcium oxide (CaO), and scandium oxide (ScO 2 ).
According to another aspect of the present invention, oxygen donor particles prepared by sintering the raw material composition of the oxygen donor particles are provided.
The oxygen donor particles may have a filling density of the active material of 1.0 to 5.0 g / ml.
The oxygen donor particles may have a diameter of 1 to 10 mm.
According to another aspect of the present invention, there is provided a process for preparing an aqueous solution of a mixture (step a) by mixing an oxygen donor particle precursor comprising an active material precursor in the form of a metal nitrate, a carrier precursor and a binder precursor, and water; Adding a dispersant to the mixture aqueous solution, adding a basic aqueous solution to form a precipitate, and preparing an oxygen donor particle powder from the precipitate (step b); Mixing and shaping the oxygen donor particle powder and the binder to form a pellet (step c); And firing the pellet to produce the oxygen donor particles (step d).
Wherein the oxygen donor particle precursor is selected from the group consisting of nitric acid iron hydrate, tungsten nitrate hydrate, cerium nitrate hydrate, zirconium nitrate hydrate, lanthanum nitrate hydrate, magnesium nitrate hydrate, strontium nitrate hydrate, calcium nitrate hydrate, scandium nitrate hydrate, And nitrate boron hydrate.
Step b) comprises the step of putting the dispersant into the aqueous mixture solution (step b-1); Adding a basic aqueous solution to the result of step b-1 to produce a precipitate (step b-2); Evaporating the solvent from the result of step b-2 to produce a precipitate gel (step b-3); And a step (b-4) of preparing an oxygen donor particle powder by drying, crushing and firing the precipitated gel.
The dispersing agent may be an anionic surfactant or a nonionic surfactant. Specific examples of the dispersant include polyethylene glycol-polypropylene glycol-polyethylene glycol block copolymer (poly (ethylene glycol) -block-poly (propylene glycol) ethylene glycol)] or ammonium polycarboxylate.
The dispersant may be used in an amount of 0.05 to 0.5 parts by weight based on 100 parts by weight of the raw material composition.
The raw material composition may further contain a defoaming agent. Examples of the defoaming agent include a silicone type, a metal soap type, a polyether type or an alcohol type defoaming agent, and specifically polyethylene glycol.
The defoaming agent may be 0.01 to 0.5 parts by weight based on 100 parts by weight of the raw material composition.
The basic aqueous solution may be at least one selected from an aqueous ammonia solution, an aqueous sodium hydroxide solution, and an aqueous potassium carbonate solution.
The calcination in step b-4 may be performed at 300 to 700 캜.
The binder may be at least one selected from kaolin, bentonite, alumina sol, silica sol, methyl cellulose and polyvinyl alcohol.
Firing in step d) may be performed in two steps of first firing at 900 to 1500 ° C and then secondarily at 700 to 1300 ° C.
In the primary firing, the heating rate may be 5 to 30 ° C per minute, and the cooling rate may be 10 to 70 ° C per second.
According to another aspect of the present invention, there is provided a process for preparing an aqueous solution of a mixture (step a) by mixing an oxygen donor particle precursor comprising an active material precursor in the form of a metal nitrate, a carrier precursor and a binder precursor, and water; Adding a dispersant to the mixture aqueous solution, adding a basic aqueous solution to form a precipitate, and preparing an oxygen donor particle powder from the precipitate (step b); Mixing and shaping the oxygen donor particle powder and the binder to form a pellet (step c); Firing the pellet to produce the oxygen donor particles (step d); And an activation step (step e) of oxygen donor particles for reducing and oxidizing the oxygen donor particles and then supplying oxygen to oxidize the oxygen donor particles.
Step e may be performed a plurality of times.
The reduction of the step (e) may be caused by at least one selected from hydrogen gas, carbon monoxide gas, carbon dioxide gas, nitrogen gas, and water vapor.
The gas may be any one selected from the group consisting of hydrogen gas, a mixed gas of a carbon monoxide gas / carbon dioxide gas, a mixed gas of a carbon monoxide gas / a carbon dioxide gas / a nitrogen gas, a mixed gas of hydrogen gas / water vapor and a mixed gas of hydrogen gas / steam / nitrogen gas Lt; / RTI >
The oxygen donor particles of the present invention can be prepared by using a binder in addition to a metal oxide and a carrier component and then performing a two-stage firing process. By optimally activating the oxygen donor particles, the oxygen donor particles can be manufactured at a relatively low firing temperature, The oxygen transfer ability is excellent, and the cost of manufacturing the particles due to the high-temperature firing of the oxygen donor particles can be reduced.
1 is a flowchart sequentially showing a method for producing oxygen donor particles of the present invention.
Fig. 2 is a flowchart sequentially showing the method of activating oxygen donor particles of the present invention.
3 is an SEM image and element distribution mapping image of oxygen donor particles prepared according to Examples 1 to 3. Fig.
Fig. 4 shows SEM images and element distribution mapping images of oxygen donor particles prepared according to Comparative Examples 1 to 4. Fig.
5 is a SEM image of the surface of oxygen donor particles according to the firing conditions of Test Example 2. Fig.
6 shows the results of TGA analysis in the reduction of oxygen donor particles according to the burning of 50% CO in Test Example 3. Fig.
7 shows the results of TGA analysis of oxygen donor particle oxidation according to the decomposition of 10% H 2 O (steam) in Test Example 3.
FIG. 8 shows the reduction reaching time according to the repeated execution of the production of the circulating hydrogen in the medium of Test Example 4. FIG.
FIG. 9 shows the results of the reduction reaction of the oxygen donor particles of Example 4 and Comparative Example 7 in a thermogravimetric analyzer. FIG.
The invention is capable of various modifications and may have various embodiments, and particular embodiments are exemplified and will be described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
Furthermore, terms including an ordinal number such as first, second, etc. to be used below can be used to describe various elements, but the constituent elements are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.
Also, when an element is referred to as being "formed" or "laminated" on another element, it may be directly attached or laminated to the front surface or one surface of the other element, It will be appreciated that other components may be present in the < / RTI >
The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.
Hereinafter, embodiments of the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.
Hereinafter, the raw material composition of the oxygen donor particle of the present invention will be described.
The raw material composition of the oxygen donor particles of the present invention comprises 1 to 50 parts by weight of a binder comprising 100 parts by weight of an active material containing a metal oxide, 20 to 400 parts by weight of a support, and at least one selected from a metal oxide and a metalloid oxide do.
The active material refers to a material that transfers oxygen to the fuel and can receive oxygen again from air or water vapor.
When the active material is contained in an amount less than the above-described content, the oxygen transfer capability may be lowered due to interaction with the carrier of the oxygen donor particle containing the same, and the reactivity may be lowered. On the contrary, when the content is larger than the above content, the pore size of the oxygen donor particles may be decreased, and the physical properties may be lowered and sintering and coagulation phenomena may occur between the active materials in the particles.
The metal oxide contained in the active material is iron oxide (FeO, Fe 2 O 3, Fe 3 O 4), oxidized tungsten (WO 2, WO 3), ceria (CeO 2), and the like, more preferably iron oxide ( Fe 2 O 3 ).
The metal oxide contained in the support may be at least one selected from the group consisting of AlO 3 , ZrO 2 , Y 2 O 3 , CeO 2 , La 2 O 3 , MgO, (SrO 2 ), calcium oxide (CaO), scandium oxide (ScO 2 ), and the like.
The carrier can support the active material uniformly distributed throughout the oxygen donor particles and can provide the oxygen donor particles after firing with sufficient strength required in the circulation process. In other words, both the function of supporting the active material and the function of bonding the oxygen donor particles to each other at the time of baking can be performed simultaneously. Further, it can play a role of suppressing the phenomenon that the metal coagulates while repeating the redox cycle at a high temperature.
If the content of the carrier is less than 20 parts by weight, the physical properties such as porosity may be lowered, sintering between the active materials in the particles and intergranular aggregation may occur. If the content exceeds 400 parts by weight, , The interaction strength with the active material increases, and the reaction performance may be deteriorated.
The metal oxide or the quasi metal oxide contained in the binder may be one selected from the group consisting of CaO, HfO 2 , La 2 O 3 , MgO, B 2 O 3 , Or mixtures thereof.
The binder may include at least one selected from calcium oxide (CaO), magnesium oxide (MgO) and boron oxide (B 2 O 3 ).
The present invention provides oxygen donor particles comprising the oxygen donor particle raw material composition.
The oxygen donor particles preferably have a packing density of 1.0 to 5.0 g / ml of the active material.
The oxygen donor particles preferably have a diameter of 1 to 10 mm, more preferably 1 to 5 mm.
It is preferable that the wear resistance of the oxygen donor particles is 15% or less when measured by a wear tester for 5 hours at a flow rate of 10.00 l / min (273.15 K, 1 bar). If the abrasion resistance exceeds 15%, fine powder is generated a lot and it is difficult to apply to the circulation process. The wear resistance is preferably close to 0%.
1 is a flowchart sequentially showing a method for producing oxygen donor particles of the present invention.
Hereinafter, a method for producing oxygen donor particles of the present invention will be described with reference to FIG.
First, mixing an oxygen donor particle precursor containing a metal nitrate and water to prepare an aqueous mixture solution (step a).
The oxygen donor particle precursor comprising the metal nitrate includes an active material precursor, a carrier precursor and a binder precursor.
The active material precursor may be nitric acid iron hydrate, tungsten nitrate hydrate, cerium nitrate hydrate.
The carrier precursor may also be aluminum nitrate hydrate, zirconium nitrate hydrate, cerium nitrate hydrate, lanthanum nitrate hydrate, magnesium nitrate hydrate, strontium nitrate hydrate, calcium nitrate hydrate, scandium nitrate hydrate.
The binder precursor may also be a hafnium nitrate hydrate, a lanthanum nitrate hydrate, a nitrate boron hydrate, or the like.
Thereafter, a dispersant is added to the mixture aqueous solution, a basic aqueous solution is added to form a precipitate, and an oxygen donor particle powder containing the oxygen donor particle raw material composition is prepared from the precipitate (step b).
Specifically, a dispersant is first added to the mixture aqueous solution (step b-1).
The dispersing agent is preferably a polyethylene glycol-polypropylene glycol-polyethylene glycol block copolymer (poly (ethylene glycol) -block-poly (propylene glycol) -block-poly (ethylene glycol)].
Next, a basic aqueous solution is added to the result of step b-1 to form a precipitate (step b-2).
The basic aqueous solution may be an ammonia aqueous solution, an aqueous sodium hydroxide solution, an aqueous potassium carbonate solution, or the like.
Thereafter, the precipitate gel is prepared by evaporating the solvent from the result of step b-2 (step b-3).
The precipitated gel is dried, pulverized and fired to prepare an oxygen donor particle powder comprising the oxygen donor particle raw material composition of the first aspect (step b-4).
The drying is preferably performed at a temperature of 90 to 120 ° C for 15 to 30 hours. The precipitate after the drying process is preferably pulverized to a size of 80 to 120 mesh. The pulverized particles can be calcined at 300 to 700 캜 for 3 hours to 7 hours.
Next, the oxygen donor particle powder and the binder are mixed and molded to prepare a pellet (step c).
The binder may be an inorganic binder such as kaolin or bentonite, a liquid inorganic binder such as alumina sol or silica sol, or an organic binder such as methylcellulose or polyvinyl alcohol.
Thereafter, the pellet is fired to produce pelletized oxygen donor particles (step d).
The firing is preferably carried out in two stages: first firing at 9,00 to 1,500 ° C, and second firing at 7,00 to 1,300 ° C.
In the first firing, the heating rate is preferably 5 to 30 DEG C per minute, and the cooling rate is preferably 10 to 70 DEG C per second.
Specifically, the pellet is placed in a high-temperature firing furnace, and the final firing temperature is raised to 900 to 1,500 ° C at a rate of 1 to 5 ° C / min, followed by rapid firing at 700 to 1,300 ° C for 3 to 10 hours .
If the calcination time is less than 3 hours, the interactions between the materials in the particles are not sufficient and the strength of the particles may be weakened. If the calcination time exceeds 10 hours, the calcination cost increases.
The temperature lowering speed is preferably 10 to 70 DEG C per second. Solid particles may coarse when less than 10 ° C / s or greater than 70 ° C / s.
Fig. 2 is a flowchart sequentially showing the method of activating oxygen donor particles of the present invention.
Hereinafter, the method for activating the oxygen donor particle of the present invention will be described with reference to FIG.
First, oxygen donor particles are prepared (steps a to d).
Since the method for producing the oxygen donor particle is as described above, the details of the method will be referred to.
Next, the pelletized oxygen donor particles are reduced and then activated by supplying oxygen to oxidize (step e).
Specifically, the reduction may be performed by supplying a gas such as a hydrogen gas, a carbon monoxide gas, a carbon dioxide gas, a nitrogen gas, or a water vapor to the pellet-shaped oxygen donor particles.
The gas may be a hydrogen gas, a mixed gas of carbon monoxide gas / carbon dioxide gas, a mixed gas of carbon monoxide gas / carbon dioxide gas / nitrogen gas, a mixed gas of hydrogen gas / water vapor, a mixed gas of hydrogen gas / steam / nitrogen gas .
Preferably, the mixed gas of carbon monoxide gas / carbon dioxide gas may include 10 to 90 wt% of carbon monoxide gas, and 10 to 90 wt% of carbon dioxide gas.
The mixed gas of carbon monoxide gas / carbon dioxide gas / nitrogen gas may include 10 to 40 wt% of carbon monoxide gas, 10 to 40 wt% of carbon dioxide gas, and 20 to 80 wt% of nitrogen gas.
In addition, the hydrogen gas / nitrogen mixed gas may contain 10 to 90 wt% of hydrogen gas, and 10 to 90 wt% of steam.
Alternatively, the mixed gas of hydrogen gas / water vapor / nitrogen gas may include 10 to 40 wt% of hydrogen gas, 10 to 40 wt% of water vapor, and 20 to 80 wt% of nitrogen gas.
The step (e) may be performed a plurality of times to improve the oxygen transfer capability of the oxygen donor particles.
The case of using oxygen donor particles containing Fe 2 O 3 as an active material as the theoretical hydrogen production mechanism will be described as an example.
first, Fe 2 O 3 To Up to FeO When the reduction is made
Fuel reactor: Fe 2 O 3 + CO = 2FeO + CO 2
Hydrogen production reactor: 2FeO + 2 / 3H 2 O = 2 / 3Fe 3 O 4 + 2 / 3H 2
Oxygen Reactor: 2 / 3Fe 3 O 4 + 1 / 6O 2 = Fe 2 O 3
2 / 3H 2 O + CO + 1 / 6O 2 = CO 2 + 2 / 3H 2
second: Fe 2 O 3 To When it is reduced to Fe
Fuel reactor: Fe 2 O 3 + 3CO = 2Fe + 3CO 2
Hydrogen producing reactor: 3Fe + 8 / 3H 2 O = 2 / 3Fe 3 O 4 + 8 / 3H 2
Oxygen Reactor: 2 / 3Fe 3 O 4 + 1 / 6O 2 = Fe 2 O 3
8 / 9H 2 O + CO + 1 / 18O 2 = CO 2 + 8 / 9H 2
Therefore, theoretically, when reducing to FeO, 2/3 mol of hydrogen can be produced per 1 mol of CO fuel, and when reducing to Fe, 8/9 mol of hydrogen can be produced per 1 mol of CO fuel.
Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the following examples are provided to further understand the present invention, and the present invention is not limited by the examples.
[Example]
Example One: Fe 2 O 3 - ZrO 2 - Binder (40: 59: 1)
(Zirconium nitrate hydrate: (lanthanum nitrate hydrate + boron nitrate boron hydrate + calcium nitrate hydrate) = 40: 59: 1 by weight) was added to the impregnation tank and the temperature was heated to 70 占 폚 while stirring.
At the same time, after adding a dispersant solvent (poly (ethylene glycol) -block-poly (ethylene glycol), commercially available from Aldrich), the pH was adjusted to 10 while gradually adding an aqueous ammonia solution to the heated aqueous solution. Respectively.
Thereafter, the precipitate was aged for 2 hours, followed by filtration and washing. The precipitate which had been subjected to the washing process several times was put back into the impregnation tank, and an aqueous NaOH solution was added thereto, and the mixture was evaporated under reduced pressure with stirring to obtain a gel state. The gel-like product was dried in a dryer at 110 DEG C for 24 hours. The dried product was pulverized into particles of 100 mesh size using a pulverizer and calcined at 500 ° C for 5 hours to produce oxygen donor particles.
The oxygen donor particles, kaolin and bentonite as binders were mixed at a weight ratio of 8: 2, and the liquid binder and water were added at a weight ratio of about 5: 5 in a kneaded state, mixed, repeatedly kneaded, And extruded into pellets having an average diameter of 4 mm. The molded pellets were dried at room temperature for about 10 hours and then dried at 110 DEG C for 6 hours.
Thereafter, the temperature was raised at a rate of 10 ° C / min, and the temperature was lowered to 950 ° C immediately after the temperature reached 1100 ° C, and the sintering process was performed in two stages for 6 hours to prepare pellet-shaped oxygen donor particles.
Example 2: Fe 2 O 3 - ZrO 2 - Binder (40: 57: 3)
Instead of the metal nitrate aqueous solution (nitric acid iron hydrate: zirconium nitrate hydrate :( lanthanum nitrate hydrate + nitrate boron hydrate + calcium nitrate hydrate) = 40: 59: Oxygen donor particles were prepared in the same manner as in Example 1, except that the lanthanum nitrate hydrate, the nitrate boron hydrate, the nitrate boron hydrate and the calcium nitrate hydrate were used in an amount of 40: 57: 3 by weight.
Example 3: Fe 2 O 3 - ZrO 2 - Binder (40: 55: 5)
Instead of the metal nitrate aqueous solution (nitric acid iron hydrate: zirconium nitrate hydrate :( lanthanum nitrate hydrate + nitrate boron hydrate + calcium nitrate hydrate) = 40: 59: Oxygen lanthanum nitrate hydrate + boron nitrate boron hydrate + calcium nitrate hydrate) = 40: 55: 5 weight ratio).
Example 4: Fe2O3 - CeO2 - Binder (40: 57: 3)
40 parts by weight of iron oxide ( Fe 2 O 3 , purity 98% or more in powder form), 57 parts by weight of ceria (CeO 2 ) and 3 parts by weight of MCB were mixed to prepare a solid raw material. Here, MCB is a mixture containing calcium oxide (CaO), magnesium oxide (MgO) and boron oxide (B 2 O 3 ), and 30 parts by weight of calcium oxide, 40 parts by weight of magnesium oxide and 30 parts by weight of boron oxide were used.
The solid raw materials in water were added with stirring with stirring to prepare a mixed slurry. Here, the content of the solid raw material relative to 100 parts by weight of the mixed slurry was 40 parts by weight. In this process, 0.1 part by weight of a polycarboxylic acid ammonium salt (Nopco, Korea) as an anionic surfactant as a dispersant and 0.1 part by weight of polyethylene glycol 1500 (JUNSEI) as a polyether alcohol were added as a defoaming agent. The mixed slurry was pulverized three times in a high energy ball mill. After the second milling, the organic binder of polyethylene glycol was added and the third milling proceeded to produce a stable and homogeneous fluidized colloidal slurry.
The prepared colloidal slurry was dried in an air atmosphere reflux dryer at 120 ° C. for 2 hours or more, and the temperature was elevated to 1,100 ° C. at a heating rate of 5 ° C./min in an air atmosphere in a firing furnace, followed by firing for 6 hours to prepare oxygen donor particles Respectively.
Comparative Example One: Fe 2 O 3 - ZrO 2 (40:60)
Instead of a metal nitrate aqueous solution (nitric acid iron hydrate: zirconium nitrate hydrate = 40: 59: 1 weight ratio) instead of a metal nitrate aqueous solution (nitric acid iron hydrate: zirconium nitrate hydrate: (lanthanum nitrate hydrate + nitrate boron hydrate + : 60 weight ratio) was used in place of the oxygen donor particles.
Comparative Example 2: CuO - Fe 2 O 3 - ZrO 2 (2:38:60)
Instead of the metal nitrate aqueous solution (nitric acid iron hydrate: zirconium nitrate hydrate: (lanthanum nitrate hydrate + nitrate boron hydrate + calcium nitrate hydrate) = 40: 59: Zirconium hydrate = 2: 38: 60 weight ratio) was used as the catalyst.
Comparative Example 3: CuO - Fe 2 O 3 - ZrO 2 (4:36:60)
Instead of the metal nitrate aqueous solution (nitric acid iron hydrate: zirconium nitrate hydrate: (lanthanum nitrate hydrate + nitrate boron hydrate + calcium nitrate hydrate) = 40: 59: Zirconium hydrate = 4: 36: 60 weight ratio) was used as the catalyst.
Comparative Example 4: CuO - Fe 2 O 3 - ZrO 2 (8:32:60)
Instead of the metal nitrate aqueous solution (nitric acid iron hydrate: zirconium nitrate hydrate: (lanthanum nitrate hydrate + nitrate boron hydrate + calcium nitrate hydrate) = 40: 59: Zirconium hydrate = 8: 32: 60 weight ratio) was used as the catalyst.
Comparative Example 5: Fe 2 O 3 - CeO 2 (40:60)
40 parts by weight of iron oxide ( Fe 2 O 3 , purity not lower than 98%, in powder form), 57 parts by weight of ceria (CeO 2) and 3 parts by weight of MCB were mixed to prepare iron oxide ( Fe 2 O 3 , purity 98 %, Powdery form) and 60 parts by weight of ceria (CeO2) were mixed to prepare a solid raw material, and the sintering was carried out at 1,000 ° C instead of 1,100 ° C. .
Comparative Example 6: Fe 2 O 3 - CeO 2 (40:60)
Oxygen donor particles were prepared in the same manner as in Comparative Example 5, except that the sintering was performed at 1,100 ° C instead of 1,000 ° C.
Comparative Example 7: Fe 2 O 3 - CeO 2 (40:60)
Oxygen donor particles were prepared in the same manner as in Comparative Example 5, except that sintering was carried out at 1,200 ° C instead of 1,000 ° C.
Comparative Example 8: Fe 2 O 3 - CeO 2 (40:60)
Oxygen donor particles were prepared in the same manner as in Comparative Example 5, except that sintering was carried out at 1,300 ° C instead of 1,000 ° C.
Comparative Example 9: Fe 2 O 3 - CeO 2 (40:60)
Oxygen donor particles were prepared in the same manner as in Comparative Example 5, except that sintering was carried out at 1400 캜 instead of 1000 캜.
The specific surface area (BET), pore volume, and average pore diameter of the oxygen donor particles prepared according to Examples 1 to 3 and Comparative Examples 1 to 4 are summarized in Table 1 below.
[Test Example]
Test Example One: SEM image
FIG. 3 is an SEM image and element distribution mapping image of oxygen donor particles prepared according to Examples 1 to 3, and FIG. 4 is an SEM image and element distribution mapping image of oxygen donor particles prepared according to Comparative Examples 1 to 4 will be. In the element distribution mapping image, Fe: red, Zr: green, O: blue, and Cu: purple.
3 and 4, the oxygen donor particles of Comparative Examples 1 to 4 exhibited a porous structure similar to the oxygen donor particles of Examples 1 to 3, but CuO had a content of 2 wt% and 4 wt% In Comparative Examples 2 and 3, it can be seen that the aggregation phenomenon occurs between the particles in the firing process as compared with Comparative Example 4 in the content of 8 wt%, and the reactivity can be lowered by such a structure. In addition, it was confirmed that the particle sizes of Comparative Examples 2 and 3 were larger than those of other oxygen donor particles. It can be seen that the specific surface area decreases and it is difficult to maintain the shape of the porous particles when the particles become larger due to the aggregation phenomenon.
Test Example 2: Surface of oxygen donor particle according to firing condition SEM image
The oxygen donor particle (a) prepared in Example 1 and the oxygen donor particle (b) prepared in the same manner as in Example 1 except that the sintering process was carried out in one step at 1100 ° C, 5 shows the SEM image of the surface of the oxygen donor particle (c) prepared by carrying out the first stage calcination step at 950 ° C.
According to FIG. 5, it can be seen that the oxygen donor particles prepared according to Example 1 have a smaller particle size than the oxygen donor particles obtained by performing the calcination in one step, and are uniform, and the porous structure is uniform.
(c), it was confirmed that the porous structure was formed due to the low firing temperature, but the physical strength was relatively low. In (b), due to the high firing temperature, some sintering was observed and the physical strength was relatively high.
On the other hand, the oxygen donor particles prepared according to Example 1 had a porous structure similar to that of the surface SEM image (b) in which the sintering process of one step was performed at 950 ° C. for 6 hours, Was more excellent.
Test Example 3: TGA ( Thermogravimetric analysis
The experimental conditions and gas conditions of TGA are as follows.
- total flow rate: 300cc / min
- Setting temperature: 700 ℃
- Crucible: Pt pan (D: 7.8 mm)
- Loading amount: 20 mg
- H 2 concentration: 10% (balanced Ar)
- CO concentration: 50% (balanced Ar)
- H 2 O (steam) concentration: 10% (balanced Ar)
- O 2 (air) concentration: 30% (balanced Ar)
FIG. 6 shows the results of TGA analysis in the reduction of oxygen donor particles according to the combustion of 50% CO, and FIG. 7 shows the results of TGA analysis in oxygen donor particle oxidation according to decomposition of 10% H 2 O (steam). Here, the conversion value is obtained as follows.
[expression]
Where m means the weight of the oxygen donor particles measured by TGA at any time and m r and m o mean the weight of the oxygen donor particles measured at the highest conversion rates in the reduction and oxidation reactions, respectively.
According to Fig. 6, Examples 1 to 3 all exhibited a high reduction rate, whereas the oxygen donor particles of Comparative Examples 2 and 3 had a low specific surface area due to agglomeration phenomenon and non-porous structure, As shown in Fig.
7, it was judged that the oxygen donor particles of Examples 1 to 3 were inhibited from sintering and the reaction rate was improved as compared with the oxygen donor particles of Comparative Examples 1 to 3. On the other hand, the oxygen donor particles of Comparative Examples 2 and 3 have a relatively low reaction rate due to the agglomeration phenomenon. Therefore, it can be seen that the oxygen donor particles of Examples 1 to 3 have a faster water decomposition reaction rate.
Test Example 4: Optimal Activation Condition of Oxygen Carrier Particles
The produced oxygen donor particles are repeatedly subjected to the reduction-oxidation reaction, and the oxygen transfer capability of the oxygen atoms on the gas phase / ion is increased, thereby improving the oxygen transfer capability. The improvement of oxygen transfer capacity can be measured by measuring the time for oxygen donor particles to reach reduction from Fe 2 O 3 to Fe in each reduction cycle.
The reduction reaching times of the oxygen donor particles according to the number of repetition of the reduction-water decomposition-air oxidation cycles are compared and shown in FIG.
According to FIG. 8, oxygen donor particles of 20 wt% Fe 2 O 3 / ZrO 2 4 mm in diameter calcined at 1,200 ° C. were pretreated under two conditions. The above two conditions were repeated five times in air after Fe reduction (condition 1: red indication), followed by Fe reduction → oxidation with 20% H 2 O → oxidation to air five times (condition 2: Black).
The two oxygen donor particles were repeatedly oxidized to Fe → reduced to 20% H2O → oxidized to air and the time to reach Fe reduction at 800 ℃ 50% methane gas was investigated.
As shown, the reduction reaction time of the oxygen donor particles of
On the other hand, the reduction reaction time of the oxygen donor particles of Condition 2 was found to be completed in 40 cycles. For rapid activation, it is more effective to repeat the air oxidation several times after the reduction without the H 2 O oxidation.
Test Example 5: Particle Oxidation and Strength Analysis
Referring to FIG. 9, the oxygen donor particles of Example 4 and Comparative Example 7 were subjected to a reduction reaction using a thermogravimetric analyzer at 900 ° C using 10% CH 4 . The extent to which oxygen is delivered to the fuel is defined as the degree of solid conversion. The rate of oxygen transfer is expressed in terms of the time (min) at which 50% of the oxygen in the particle is transferred.
Particle size = oxide (Fe 2 O 3 particles, the weight of the condition (g) - thermogravimetric particle weight (g)) / (Fe 2 O 3 particle state weight (g) - weight of the particles (g of Fe state))
Referring to FIG. 9 and Table 3, it can be seen that the reduction degree of the sintered particles calcined at 1,100 ° C. containing MCB is lower than that of the sintered particles calcined at 1,200 ° C. The rate of oxygen transfer to the point where 50% of the oxygen of the oxygen donor particles was transferred to the methane gas was confirmed to be 18.8% and 12.0%, respectively.
On the other hand, the oxygen transfer rate (12.0%) of the oxygen donor particles added with MCB is slightly less than the transfer rate (13.6%) of the particles fired at about 1,100 ° C as compared with the conventional particles. However, the physical strength (N) is higher than the strength of the calcined particles at 1,400 ℃ (335N) (485N). This suggests that the oxygen donor particles added with MCB show stable durability against external physical impact and have a good oxygen transfer capacity, which makes them suitable for internal circulation process.
(% / min)
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, This is possible.
Claims (12)
20 to 400 parts by weight of a carrier; And
1 to 50 wt% of a binder containing at least one selected from calcium oxide (CaO), hafnium oxide (HfO 2 ), lanthanum oxide (La 2 O 3 ), magnesium oxide (MgO) and boron oxide (B 2 O 3 ) Wherein the oxygen donor particles have an average particle size of not more than 100 nm.
Wherein the binder comprises at least one selected from calcium oxide (CaO), magnesium oxide (MgO) and boron oxide (B 2 O 3 ).
Characterized in that the metal oxide contained in the active material comprises iron oxide (FeO, Fe 2 O 3, Fe 3 O 4), tungsten oxide (WO 2, WO 3), and ceria (CeO 2) at least one selected from By weight based on the total weight of the particles.
Wherein the support is selected from the group consisting of AlO 3 , ZrO 2 , Y 2 O 3 , CeO 2 , La 2 O 3 , MgO, SrO 2, ), Calcium oxide (CaO), and scandium oxide (ScO 2 ).
Wherein the oxygen donor particle has a filling density of the active material of 1.0 to 5.0 g / ml.
Wherein the oxygen donor particle has a diameter of 1 to 10 mm.
Adding a dispersant to the mixture aqueous solution, adding a basic aqueous solution to form a precipitate, and preparing an oxygen donor particle powder from the precipitate (step b);
Mixing and shaping the oxygen donor particle powder and the binder to form a pellet (step c); And
And firing the pellet to produce the oxygen donor particle of claim 4. The method of producing oxygen donor particles according to claim 1,
Step (b)
Introducing a dispersant into the aqueous mixture solution (step b-1);
Adding a basic aqueous solution to the result of step b-1 to produce a precipitate (step b-2);
Evaporating the solvent from the result of step b-2 to produce a precipitate gel (step b-3); And
(Step b-4) of preparing an oxygen donor particle powder by drying, crushing and firing the precipitated gel;
By weight based on the total weight of the particles.
Wherein the dispersing agent is a polyethylene glycol-polypropylene glycol-polyethylene glycol block copolymer (poly (ethylene glycol) -block-poly (propylene glycol) -block-poly (ethylene glycol)].
Adding a dispersant to the mixture aqueous solution, adding a basic aqueous solution to form a precipitate, and preparing an oxygen donor particle powder from the precipitate (step b);
Mixing and shaping the oxygen donor particle powder and the binder to form a pellet (step c);
Firing the pellet to produce the oxygen donor particles of claim 4 (step d); and
An activation step (step e) of oxygen donor particles for reducing oxygen donor particles in step d and then oxidizing them by supplying oxygen;
≪ / RTI >
Wherein the step (e) is performed a plurality of times.
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| CN110982580A (en) * | 2019-12-12 | 2020-04-10 | 华中科技大学 | Preparation method and product of composite material oxygen carrier with compact structure |
| CN113105929A (en) * | 2021-04-15 | 2021-07-13 | 安徽工程大学 | ZrO (ZrO)2Modified Fenton iron mud-based oxygen carrier and preparation method and application thereof |
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| CN110982580A (en) * | 2019-12-12 | 2020-04-10 | 华中科技大学 | Preparation method and product of composite material oxygen carrier with compact structure |
| CN113105929A (en) * | 2021-04-15 | 2021-07-13 | 安徽工程大学 | ZrO (ZrO)2Modified Fenton iron mud-based oxygen carrier and preparation method and application thereof |
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