WO2024102480A1

WO2024102480A1 - Calcination of carbonate materials

Info

Publication number: WO2024102480A1
Application number: PCT/US2023/037162
Authority: WO
Inventors: Robert Louis ZELLER III; Alexander G. BAETZ
Original assignee: Carbon Engineering Ulc
Priority date: 2022-11-11
Filing date: 2023-11-10
Publication date: 2024-05-16

Abstract

A calciner includes a reactor vessel and a heating system. An interior volume of the reactor vessel is in communication with at least one inlet and at least one outlet. The at least one inlet includes a solids inlet configured to provide the solid carbonate material to the interior volume and a fluidization gas inlet configured to provide a fluidization gas stream. The at least one outlet includes a solids outlet configured to convey a solid oxide material from the interior volume and an exhaust gas outlet configured to convey an exhaust gas stream from the interior volume. The heating system includes an electric heater operable to heat a circulating gas stream and a heat exchanger thermally coupled to the electric heater and configured to transfer heat from the circulating gas stream to the fluidization gas stream to heat the fluidization gas stream.

Description

CALCINATION OF CARBONATE MATERIALS

TECHNICAL FIELD

[0001] This disclosure relates to systems, apparatus, and methods for calcination of carbonate materials.

BACKGROUND

[0002] Capturing carbon dioxide (CO2) from the atmosphere is one approach to mitigating greenhouse gas emissions and slowing climate change. However, many technologies designed for CO2 capture from point sources, such as flue gas of industrial facilities, are generally ineffective in capturing CO2 from the atmosphere due to the significantly lower CO2 concentrations and large volumes of air required to process CO2 from the atmosphere. In recent years, progress has been made in finding technologies better suited to capture CO2 directly from the atmosphere. Some of these direct air capture (DAC) systems use a solid sorbent where an active agent is attached to a substrate. These DAC systems typically employ a cyclic adsorption-desorption process where, after the solid sorbent is saturated with CO2, it releases the CO2 using a humidity or thermal swing and is regenerated.

[0003] Other DAC systems use a liquid sorbent (sometimes referred to as a solvent) to capture CO2 from the atmosphere. An example of such a gas-liquid contact system would be one where a fan is used to draw air across a high surface area packing that is wetted with a solution comprising the liquid sorbent. CO2 in the air reacts with the liquid sorbent. The rich solution is further processed downstream to regenerate a lean solution and to release a concentrated CO2 stream.

[0004] During processing downstream, liquid and solid sorbent systems may need to liberate CO2 from a carbonate material formed when the CO2 is reacted with the sorbent material. For carbonates in solid form, this may be achieved with a heated reactor, sometimes referred to as a calciner, which heats the carbonate material to liberate CO2 for storage or further processing. Some of these reactors combust hydrocarbons to generate the thermal energy required for reacting the carbonate material, which can increase the carbon intensity of the overall process. SUMMARY

[0005] In an example implementation, a system includes a reactor that includes an interior volume configured to calcine a solid carbonate material, the interior volume in communication with at least one inlet and at least one outlet, the at least one inlet including a solids inlet configured to provide the solid carbonate material to the interior volume to form a bed of the solid carbonate material and a fluidization gas inlet configured to provide a fluidization gas stream to fluidize the bed of the solid carbonate material, and the at least one outlet including a solids outlet configured to convey a solid oxide material from the interior volume and an exhaust gas outlet configured to convey an exhaust gas stream from the interior volume; a piping network that includes a fluidization pipeline configured to flow the fluidization gas stream to the fluidization gas inlet, and at least one heat transfer pipeline; and a heating system that includes at least one electric heater coupled to the at least one heat transfer pipeline and operable to heat a circulating gas stream, and at least one heat exchanger coupled to the at least one electric heater through the at least one heat transfer pipeline and to the fluidization pipeline, the at least one heat exchanger operable to transfer heat from the circulating gas stream to the fluidization gas stream to heat the fluidization gas stream to a calcination temperature for the solid carbonate material.

[0006] In an aspect combinable with the example implementation, the piping network includes at least one preheater pipeline; and the system further includes a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline.

[0007] Another aspect combinable with any of the previous aspects further includes a blower in fluid communication with the fluidization gas inlet through the fluidization pipeline.

[0008] In another aspect combinable with any of the previous aspects, the fluidization gas stream includes a CO2 gas stream.

[0009] In another aspect combinable with any of the previous aspects, the piping network includes a recycle pipeline in fluid communication with the exhaust gas outlet and with the fluidization pipeline.

[0010] In another aspect combinable with any of the previous aspects, the piping network includes at least one preheater pipeline and a condenser pipeline, and the system further includes a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline; and a water knock-out unit fluidly coupled to the pre-heater heat exchanger through the condenser pipeline and configured to receive a cooled exhaust gas stream from the pre-heater heat exchanger, the water knock-out unit fluidly coupled to the recycle pipeline and to the fluidization gas inlet, the water knock-out unit operable to condense water vapor from the cooled exhaust gas stream.

[0011] In another aspect combinable with any of the previous aspects, the piping network includes at least one preheater pipeline, and the system further includes a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline, the pre-heater heat exchanger configured to cool the exhaust gas stream and form a cooled exhaust gas stream and heated solid carbonate material, and the recycle pipeline in fluid communication with the preheater heat exchanger to flow at least part of the cooled exhaust gas stream to the fluidization gas inlet.

[0012] In another aspect combinable with any of the previous aspects, the piping network includes at least one preheater pipeline and a condenser pipeline, and the system further includes: a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline, the pre-heater heat exchanger configured to cool the exhaust gas stream and form a cooled exhaust gas stream and heated solid carbonate material, a water knock-out unit fluidly coupled to the preheater heat exchanger through the condenser pipeline and configured to receive the cooled exhaust gas stream from the pre-heater heat exchanger, the water knock-out unit operable to condense water vapor from the cooled exhaust gas stream to form a dry exhaust gas stream; and the water knock-out unit fluidly coupled to the recycle pipeline and to the fluidization gas inlet to flow the dry exhaust gas stream to the fluidization gas stream.

[0013] In another aspect combinable with any of the previous aspects, the piping network includes a solid discharge pipeline that extends from the solids outlet; the at least one inlet includes a steam inlet; and the system further includes a steam heat exchanger thermally coupled to the solid discharge pipeline and to a source of water, and fluidly coupled to the steam inlet, the steam heat exchanger operable to transfer heat from the solid oxide material to water to generate steam for the steam inlet.

[0014] In another aspect combinable with any of the previous aspects, the piping network includes a solid discharge pipeline that extends from the solids outlet; and the system further includes a steam heat exchanger thermally coupled to the solid discharge pipeline and to a source of water, and fluidly coupled to the fluidization pipeline, the steam heat exchanger operable to transfer heat from the solid oxide material to water to generate steam for the fluidization pipeline. [0015] In another aspect combinable with any of the previous aspects, the piping network includes a solid discharge pipeline that extends from the solids outlet; and the system further includes a solids cooler thermally coupled to the solid discharge pipeline and to the fluidization pipeline, the solids cooler positioned upstream of the heat exchanger and operable to transfer heat from the solid oxide material to the fluidization gas.

[0016] In another aspect combinable with any of the previous aspects, the circulating gas stream includes nitrogen.

[0017] In another aspect combinable with any of the previous aspects, the solid carbonate material is solid calcium carbonate (CaCCh).

[0018] In another aspect combinable with any of the previous aspects, the at least one electric heater includes a plurality of electric heaters and the at least one heat exchanger includes a plurality of heat exchangers, each electric heater of the plurality of electric heaters arranged with a heat exchanger of the plurality of heat exchangers to form a parallel arrangement of electric heaters and heat exchangers, the parallel arrangement of electric heaters and heat exchangers operable to collectively heat the fluidization gas stream to the calcination temperature.

[0019] In another example implementation, a method of calcining a solid carbonate material includes: providing the solid carbonate material to a reactor to form a bed of the solid carbonate material; heating a circulating gas stream with an electric heater; transferring heat from the circulating gas stream to a fluidization gas stream to form a heated fluidization gas stream at a calcination temperature for the solid carbonate material; flowing the heated fluidization gas stream through the bed of the solid carbonate material in the reactor to fluidize the bed of the solid carbonate material, and to calcine the solid carbonate material to form a carbon dioxide (CO2) gas stream and a solid oxide material; and discharging at least a portion of the CO2 gas stream and at least a portion of the solid oxide material from the reactor.

[0020] In an aspect combinable with the example implementation, discharging the at least a portion of the CO2 gas stream includes transferring heat from the CO2 gas stream to the solid carbonate material to form a heated solid carbonate material; and providing the solid carbonate material to the reactor includes providing the heated solid carbonate material to the reactor. [0021] In another aspect combinable with any of the previous aspects, flowing the heated fluidization gas stream through the bed of the solid carbonate material includes blowing the heated fluidization gas stream through the bed of the solid carbonate material in the reactor.

[0022] In another aspect combinable with any of the previous aspects, transferring heat from the circulating gas stream to the fluidization gas stream to form the heated fluidization gas stream includes transferring heat from the circulating gas stream to the at least a portion of the CO2 gas stream discharged from the reactor to form a heated CO2 fluidization gas stream.

[0023] In another aspect combinable with any of the previous aspects, providing the solid carbonate material to the reactor includes providing the solid carbonate material with water content to a heat exchanger; and the method further includes: in the heat exchanger, transferring heat from the CO2 gas stream discharged from the reactor to the solid carbonate material with the water content to form a heated solid carbonate material, a cooled CO2 gas stream, and a steam stream; providing the heated solid carbonate material to the reactor; and discharging the cooled CO2 gas stream and the steam stream from the heat exchanger.

[0024] In another aspect combinable with any of the previous aspects, providing the solid carbonate material to the reactor includes providing the solid carbonate material to a heat exchanger; and the method further includes: in the heat exchanger, transferring heat from the CO2 gas stream discharged from the reactor to the solid carbonate material to form a heated solid carbonate material and a cooled CO2 gas stream; providing the heated solid carbonate material to the reactor; and discharging the cooled CO2 gas stream from the heat exchanger; and wherein transferring heat from the circulating gas stream to the fluidization gas stream to form the heated fluidization gas stream includes transferring heat from the circulating gas stream to at least a portion of the cooled CO2 gas stream to form a heated CO2 fluidization gas stream.

[0025] In another aspect combinable with any of the previous aspects, transferring heat from the circulating gas stream to the fluidization gas stream to form the heated fluidization gas stream includes transferring heat from the circulating gas stream to at least a portion of the cooled CO2 gas stream to form a heated CO2 fluidization gas stream.

[0026] In another aspect combinable with any of the previous aspects, discharging the cooled CO2 gas stream and the steam stream from the heat exchanger includes discharging a mixed gas stream including the cooled CO2 gas stream and the steam stream from the heat exchanger; and the method further includes condensing steam from the mixed gas stream to form a reduced- water-content cooled CO2 gas stream, wherein transferring heat from the circulating gas stream to the fluidization gas stream to form the heated fluidization gas stream includes transferring heat from the circulating gas stream to at least a portion of the reduced-water-content cooled CO2 gas stream to form a heated CO2 fluidization gas stream.

[0027] In another aspect combinable with any of the previous aspects, discharging the at least a portion of the CO2 gas stream and the at least a portion of the solid oxide material from the reactor includes transferring heat from the at least a portion of the solid oxide material to a water stream to form a solids-heated steam stream; and the method further includes flowing the solids- heated steam stream through the bed of the solid carbonate material in the reactor to fluidize the bed of the solid carbonate material.

[0028] In another aspect combinable with any of the previous aspects, discharging the at least a portion of the CO2 gas stream and the at least a portion of the solid oxide material from the reactor includes transferring heat from the at least a portion of the solid oxide material to a water stream to form a solids-heated steam stream; and flowing the heated fluidization gas stream through the bed of the solid carbonate material in the reactor to fluidize the bed of the solid carbonate material includes flowing the heated fluidization gas stream and the solids-heated steam stream through the bed of the solid carbonate material in the reactor to fluidize the bed of the solid carbonate material.

[0029] In another aspect combinable with any of the previous aspects, heating the circulating gas stream with the electric heater includes heating a nitrogen circulating gas stream with the electric heater.

[0030] In another aspect combinable with any of the previous aspects, providing the solid carbonate material to the reactor includes providing solid calcium carbonate (CaCCh) to the reactor.

[0031] In another aspect combinable with any of the previous aspects, discharging the at least a portion of the CO2 gas stream and the at least a portion of the solid oxide material from the reactor includes: transferring heat from the at least a portion of the solid oxide material to the fluidization gas stream; and transferring heat from the circulating gas stream to the fluidization gas stream to form the heated fluidization gas stream at the calcination temperature. [0032] In another aspect combinable with any of the previous aspects, providing the solid carbonate material to the reactor includes providing solid calcium carbonate (CaCCh) to the reactor.

[0033] In another aspect combinable with any of the previous aspects, flowing the heated fluidization gas stream through the bed of the solid carbonate material in the reactor includes flowing a heated CO2 fluidization gas stream through the bed of the solid carbonate material in the reactor to fluidize the bed of the solid carbonate material, and to calcine the solid carbonate material to form the CO2 gas stream and the solid oxide material.

[0034] In another example implementation, a system for capturing carbon dioxide (CO2) from atmospheric air includes: at least one gas-liquid contactor operable to absorb at least a portion of the CO2 from the atmospheric air into a carbonate process solution; at least one carbonate- growth reactor in fluid communication with the at least one gas-liquid contactor, the at least one carbonate-growth reactor operable to react the carbonate process solution with calcium hydroxide to grow solid calcium carbonate (CaCCh); a calciner in communication with the at least one carbonate-growth reactor, the calciner including an interior volume in communication with at least one inlet and at least one outlet, the at least one inlet including a solids inlet configured to receive the solid CaCCh from the at least one carbonate-growth reactor to form a bed of the solid CaCCh in the interior volume and a fluidization gas inlet configured to receive a fluidization gas stream to fluidize the bed of the solid CaCCh in the interior volume, and the at least one outlet including a solids outlet configured to convey a solid oxide material from the interior volume and an exhaust gas outlet configured to convey an exhaust gas stream from the interior volume; a piping network including a fluidization pipeline configured to flow the fluidization gas stream to the fluidization gas inlet and at least one heat transfer pipeline; and a heating system including at least one electric heater thermally coupled to the at least one heat transfer pipeline and operable to heat a circulating gas stream and at least one heat exchanger thermally coupled to the at least one electric heater through the at least one heat transfer pipeline and to the fluidization pipeline, the at least one heat exchanger operable to transfer heat from the circulating gas stream to the fluidization gas stream to heat the fluidization gas stream to a calcination temperature for the solid CaCCh

[0035] In an aspect combinable with the example implementation, the piping network further includes at least one preheater pipeline; and the system further includes a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline.

[0036] In another aspect combinable with any of the previous aspects, the system further includes a blower in fluid communication with the fluidization gas inlet through the fluidization pipeline.

[0037] In another aspect combinable with any of the previous aspects, the fluidization gas stream comprises a CO2 gas stream.

[0038] In another aspect combinable with any of the previous aspects, the piping network includes a recycle pipeline in fluid communication with the exhaust gas outlet and with the fluidization pipeline.

[0039] In another aspect combinable with any of the previous aspects, the piping network includes at least one preheater pipeline and a condenser pipeline; and the system further includes: a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline; and a water knock-out unit fluidly coupled to the pre-heater heat exchanger through the condenser pipeline and configured to receive a cooled exhaust gas stream from the pre-heater heat exchanger, the water knock-out unit fluidly coupled to the recycle pipeline and to the fluidization gas inlet, the water knock-out unit operable to condense water vapor from the cooled exhaust gas stream.

[0040] In another aspect combinable with any of the previous aspects, the piping network includes at least one preheater pipeline; and the system further includes: a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline, the preheater heat exchanger configured to cool the exhaust gas stream and form a cooled exhaust gas stream and heated solid carbonate material; and the recycle pipeline in fluid communication with the pre-heater heat exchanger to flow at least part of the cooled exhaust gas stream to the fluidization gas inlet.

[0041] In another aspect combinable with any of the previous aspects, the piping network includes at least one preheater pipeline and a condenser pipeline; and the system further includes: a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline, the pre-heater heat exchanger configured to cool the exhaust gas stream and form a cooled exhaust gas stream and heated solid carbonate material; a water knock-out unit fluidly coupled to the preheater heat exchanger through the condenser pipeline and configured to receive the cooled exhaust gas stream from the pre-heater heat exchanger, the water knock-out unit operable to condense water vapor from the cooled exhaust gas stream to form a dry exhaust gas stream; and the water knock-out unit fluidly coupled to the recycle pipeline and to the fluidization gas inlet to flow the dry exhaust gas stream to the fluidization gas stream.

[0042] In another aspect combinable with any of the previous aspects, the piping network includes a solid discharge pipeline that extends from the solids outlet; the at least one inlet includes a steam inlet; and the system further includes a steam heat exchanger thermally coupled to the solid discharge pipeline and to a source of water, and fluidly coupled to the steam inlet, the steam heat exchanger operable to transfer heat from the solid oxide material to water to generate steam for the steam inlet.

[0043] In another aspect combinable with any of the previous aspects, the piping network includes a solid discharge pipeline that extends from the solids outlet; and the system further includes a steam heat exchanger thermally coupled to the solid discharge pipeline and to a source of water, and fluidly coupled to the fluidization pipeline, the steam heat exchanger operable to transfer heat from the solid oxide material to water to generate steam for the fluidization pipeline. [0044] In another aspect combinable with any of the previous aspects, the piping network includes a solid discharge pipeline that extends from the solids outlet; and the system further includes a solids cooler thermally coupled to the solid discharge pipeline and to the fluidization pipeline, the solids cooler positioned upstream of the at least one heat exchanger and operable to transfer heat from the solid oxide material to the fluidization gas.

[0045] In another aspect combinable with any of the previous aspects, the circulating gas stream includes nitrogen.

[0046] In another aspect combinable with any of the previous aspects, the solid carbonate material is solid calcium carbonate (CaCOfl

[0047] In another aspect combinable with any of the previous aspects, the at least one electric heater includes a plurality of electric heaters and the at least one heat exchanger includes a plurality of heat exchangers, each electric heater of the plurality of electric heaters arranged with a heat exchanger of the plurality of heat exchangers to form a parallel arrangement of electric heaters and heat exchangers. [0048] In another aspect combinable with any of the previous aspects, wherein the at least one electric heater includes a plurality of electric heaters and the at least one heat exchanger includes a plurality of heat exchangers, each electric heater of the plurality of electric heaters arranged with a heat exchanger of the plurality of heat exchangers to form a series arrangement of electric heaters and heat exchangers, the series arrangement of electric heaters and heat exchangers operable to collectively heat the fluidization gas stream to the calcination temperature.

[0049] In another example implementation, a calciner includes: a reactor vessel including an interior volume and configured to calcine a solid carbonate material, the interior volume in communication with at least one inlet and with at least one outlet, the at least one inlet including a solids inlet configured to provide the solid carbonate material to the interior volume to form a bed of the solid carbonate material and a fluidization gas inlet configured to provide a fluidization gas stream to fluidize the bed of the solid carbonate material, the at least one outlet including a solids outlet configured to convey a solid oxide material from the interior volume and an exhaust gas outlet configured to convey an exhaust gas stream from the interior volume; and a heating system including an electric heater operable to heat a circulating gas stream and a heat exchanger thermally coupled to the electric heater and configured to transfer heat from the circulating gas stream to the fluidization gas stream to heat the fluidization gas stream to a calcination temperature for the solid carbonate material.

[0050] The details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG. 1 is a perspective view of an example calcination system of the present disclosure.

[0052] FIG. 2A is a perspective view of an example implementation of a heating system of the calcination system of FIG. 1.

[0053] FIG. 2B is a perspective view of another example implementation of a heating system of the calcination system of FIG. 1. [0054] FIG. 2C is a perspective view of another example implementation of a heating system of the calcination system of FIG. 1.

[0055] FIG. 2D is a perspective view of another example implementation of a heating system of the calcination system of FIG. 1.

[0056] FIG. 3 is a perspective view of an example implementation of a calciner of the present disclosure.

[0057] FIG. 4 is a perspective view of another example calcination system of the present disclosure.

[0058] FIG. 5 is a perspective view of another example calcination system of the present disclosure.

[0059] FIG. 6 is a perspective view of another example calcination system of the present disclosure.

[0060] FIG. 7 is a perspective view of another example calcination system of the present disclosure.

[0061] FIG. 8 is a perspective view of another example calcination system of the present disclosure.

[0062] FIG. 9 is a flow chart of an example method of calcining a solid carbonate material.

[0063] FIG. 10 is a schematic illustration of a direct air capture system having a calcination system of the present disclosure.

[0064] FIG. 11 is a schematic diagram of an example control system for a calcination system of the present disclosure.

DETAILED DESCRIPTION

[0065] Referring to FIG. 1, the present disclosure relates to the calcination of solid carbonate materials 101. The calcination occurs in a calcination system 100, and more particularly, in a reactor 110 of the calcination system 100. The solid carbonate material 101 is fed to the reactor 110 and undergoes a thermal treatment whereby the solid carbonate material 101 is raised to a high temperature without melting under restricted supply of oxygen, for the purpose of converting the solid carbonate material 101 into a solid oxide material 103 and a carbon dioxide (CO2) gas stream 105. In one possible configuration, an example of which is provided in FIG. 1, the solid carbonate material 101 is, or includes, calcium carbonate (CaCCh). In such a configuration, the calcination reaction in the reactor 110 involves the decomposition of CaCCh at a calcination temperature of between 700-1050°C into solid calcium oxide (CaO) and CO2 gas, according to the following chemical reaction:

[0066] CaCO₃(s) CaO(s) + CO₂(g)

[0067] The reactor 110 can also calcine other solid carbonate materials 101. Non-limiting examples of other solid carbonate materials 101 that can be calcined in the reactor 110 to yield the solid oxide material 103 and the CO2 gas stream 105 include magnesium carbonate compounds, and carbonates containing one or more of sodium, potassium, uranium, aluminum, titanium, nickel, iron, copper, zinc, lead, manganese, strontium, cobalt, cadmium, bismuth, and barium. Other possible examples of solid carbonate materials 101 that can be calcined in the reactor 110 to yield the solid oxide material 103 and the CO2 gas stream 105 include both organic and inorganic precipitated materials with a carbonate, such as carbamates.

[0068] In addition to having varied chemical compositions, the solid carbonate material 101 may be sourced from various industries and applications, including from the calcination system 100 itself. The solid carbonate material 101 may be provided to the reactor 110 in different forms, such as pellets, pebbles, fines, ooids, and the like, and may consist of a range of sizes, from small particles as seen in applications that generate lime mud (e.g., between about 1 micron to about 100 microns diameter), to mid-range as seen in applications where carbonate pellets are grown through crystallization and/or precipitation (e.g., between about 50 microns to about 2 millimeters in diameter), up to larger ranges as seen in applications where the carbonate is either formed into pellets, bricks or other shapes, or is mined from geological sources (e.g., up to several centimeters in diameter).

[0069] Referring to FIG. 1, the calcination system 100 is a collection of apparatuses, piping, componentry, mechanisms and objects which work together to calcine the solid carbonate material 101. The calcination system 100 includes the reactor 110. The reactor 110 is a vessel or other body that is at least partially hollow, and which is capable of receiving the solid carbonate material 101 and supporting the calcination reaction. The reactor 110 may thus be referred to herein as a “reactor vessel 110,” or simply as a “calciner 110”. The reactor 110 has an interior 112 which is some or all of the inner volume of the reactor 110 and which is delimited by the walls of the reactor 110. The interior 112 is the location of the reactor 110 in which the calcination reaction takes place, and is thus configured for receiving the solid carbonate material 101. The interior 112 communicates with multiple inlets 114 and multiple outlets 116 of the reactor 110. In some aspects, the term “communicates,” with respect to the present disclosure, means that solids, liquids, gases and/or combinations of any of these material phases are received in, and discharged from, the interior 112 of the reactor 110 via the inlets 114 and via the outlets 116. For example, and referring to FIG. 1, one of the inlets 114 is a solids inlet 114S through which the solid carbonate material 101 is received in the interior 112. Another one of the inlets 114 is a fluidization gas inlet 114F through which a fluidization gas stream 107 is received in the interior 112. Similarly, one of the outlets 116 is a solids outlet 116S through which the solid oxide material 103 is conveyed or discharged from the interior 112 after calcination. Another one of the outlets 116 is an exhaust gas outlet 116E from which an exhaust gas stream 108, which includes the CO2 gas stream 105, is discharged from the interior 112 of the reactor 110. In some configurations, an example of which is provided in FIG. 1 , the reactor 110 includes or is coupled to one or more solid-gas separators, such as one or more cyclones 113, which separate out particles of the solid oxide material 103 which might be entrained in the exhaust gas stream 108. The inlets 114 and the outlets 116 may be any ports, openings or other similar accesses in a wall of the reactor 110, or defined by one or more flanges of the reactor 110. Although sometimes described and shown in the present disclosure as separate from one another, one or more of the inlets 114 may be combined with each other, and/or with one or more of the outlets 116. Similarly, one or more of the outlets 116 may be combined with each other, and/or with one or more of the inlets 114. Each inlet 114 and each outlet 116 may themselves include multiple branches or ports to define a plural inlet 114 or a plural outlet 116.

[0070] Referring to FIG. 1, the calcination system 100 includes a piping network 120. The piping network 120 is a series of interconnected pipes, lines, and other similar conduits through which different materials are moved to, through and/or from the calcination system 100. The piping network 120 includes multiple pipelines through which materials are moved from one location to another. One of the pipelines of the piping network 120 is a solids feed pipeline 122 which conveys the solid carbonate material 101 to the solids inlet 114S. In the example of the reactor 110 of FIG. 1, the solids inlet 114S is located at a top of the body of the reactor 110. Consequently, the solid carbonate material 101 supplied via the solids feed pipeline 122 to the solids inlet 114S falls due to gravity and collects toward the bottom of the body of the reactor 110, forming a bed 109 of the solid carbonate material 101. In an alternate configuration, the solids feed pipeline 122 includes, or feeds, a hopper at the solids inlet 114S. Other pipelines of the piping network 120 include heat transfer pipelines 126, which are used to transfer heat to the fluidization gas stream 107, as explained in greater detail below. Another pipeline of the piping network 120 is an exhaust gas pipeline 121 that is fluidly coupled to, and extends from, the exhaust gas outlet 116E. Yet another pipeline of the piping network 120 is a solids discharge pipeline 127 that is coupled to, and extends from, the solids outlet 116S, and which helps to convey the calcined solid oxide material 103 from the interior 112 of the reactor 110. Each of the pipelines of the piping network 120 may include, or be formed of, one or more pipes or one or more pipe segments, and include any other devices (e.g., valves, flanges, ports, etc.) needed for the pipelines to move the material associated with the pipeline in the present disclosure.

[0071] Yet another pipeline of the piping network 120 is a fluidization pipeline 124. The fluidization pipeline 124 flows the fluidization gas stream 107 to the fluidization gas inlet 114F so that the fluidization gas stream 107 can fluidize the bed 109 of the solid carbonate material 101 in the reactor 110. Thus, in at least the implementation of FIG. 1, the reactor 110 flows gas (e.g., the fluidization gas stream 107) through a solid granular material (e.g., the bed 109 of the solid carbonate material 101) at flow rates that are high enough to suspend the solid carbonate material 101 in the interior 112 and cause the solid carbonate material 101 to behave as though it were a fluid. Thus, in at least the implementation of FIG. 1 , the reactor 110 is a fluidized bed reactor 110, or a fluidized bed calciner 110. In some configurations of the reactor 110, an example of which is provided in FIG. 1, the fluidized bed reactor 110 includes componentry such as a distributor plate 118 which is perforated. The fluidization gas stream 107 enters the fluidized bed reactor 110 via the fluidization gas inlet 114F near the bottom portion of the body of the reactor 110, flows through the distributor plate 118 and flows up through the bed 109 of the solid carbonate material 101, where it fluidizes and mixes with both the solid carbonate material 101 and solid oxide material 103.

[0072] In some configurations, such as in FIG. 1, the fluidization gas stream 107 is or includes CO2. In some configurations, the concentration of CO2 in the fluidization gas stream 107 is at least 50% v/v. In some configurations, the concentration of CO2 in the fluidization gas stream 107 is at least 90% v/v. In configurations where the fluidization gas stream 107 is primarily or “pure” CO2, the concentration of CO2 in the fluidization gas stream 107 is between 90% and 99.9% v/v. The fluidization gas stream 107 may have other compositions. For example, the fluidization gas stream 107 may be, or may include, atmospheric air. In such a configuration, the calcination system 100 may include a scrubber or air separation downstream of the reactor 110 to remove nitrogen- containing compounds from the exhaust gas stream 108 of the reactor 110. In another possible configuration, an example of which is described in greater detail below, the fluidization gas stream 107 may be, or may include, steam. In such a configuration, the calcination system 100 may include a condenser or knock-out unit downstream of the reactor 110 to remove water from the exhaust gas stream 108 of the reactor 110. In some configurations, an example of which is shown in FIG. 1, the fluidization gas stream 107 flows through the reactor 110 by entering the reactor 110 at the fluidization gas inlet 114F and by being discharged from the reactor 110 at the exhaust gas outlet 116E. In other possible configurations, the fluidization gas stream 107 is composed of some of the exhaust gas stream 108 discharged from the reactor 110, as described in greater detail below.

[0073] Referring to FIG. 1, the calcination system 100 includes a heating system 130. In the configuration of the calcination system 100 of FIG. 1, the heating system 130 is a subsystem of the calcination system 100 that is separate from the reactor 110. In other possible configurations, an example of which is described in greater detail below, the heating system 130 is a component or feature of the calciner 110 itself. The heating system 130 is configured to provide thermal energy to the fluidization gas stream 107 so as to heat the fluidization gas stream 107 to a temperature sufficient to achieve calcination of the solid carbonate material 101, referred to herein as a “calcination temperature”. The calcination temperature will vary depending on the type of solid carbonate material 101 being calcined in the reactor 110 and the conditions within the reactor 110. For example, in the configuration where the solid carbonate material 101 is or includes CaCCh, the calcination temperature may be in the range of approximately 450°C to 900°C.

[0074] Referring to FIG. 1, the heating system 130 includes an electric heater 132 and a heat exchanger 134. The electric heater 132 is thermally coupled to the heat exchanger 134 via the heat transfer pipelines 126, in which a circulating gas stream 136 circulates between the electric heater 132 and the heat exchanger 134. The heat exchanger 134 is in fluid communication with the fluidization pipeline 124 and with the fluidization gas inlet 114F. In the configuration of FIG. 1, the heat exchanger 134 is a gas-to-gas heat exchanger 134 which transfers thermal energy between the circulating gas stream 136 and the fluidization gas stream 107. Other configurations of the heat exchanger 134 are possible, as described in greater detail below.

[0075] Referring to FIG. 1, an electric potential from an electrical source 135 is applied across the electric heater 132 to generate thermal energy. In some configurations, the electricity provided to the electric heater 132 from the electrical source 135 is derived from a renewable or low-carbon source (e.g., photovoltaic energy, wind energy, hydroelectric energy, nuclear energy, etc.). In some configurations, the electricity provided to the electric heater 132 from the electrical source 135 is an intermittent source of electricity, which may be a renewable or low-carbon source (e.g., photovoltaic energy, wind energy, hydroelectric energy, nuclear energy, etc.). The electrical source 135 may be, or may include, devices or apparatus to store electrical energy, such as one or more batteries. The electrical source 135 may be an electrical grid that provides electrical energy from a central electrical grid.

[0076] The electric heater 132 is configured to transfer the thermal energy to the circulating gas stream 136 circulating in the heat transfer pipelines 126. The heated gas stream 136 is flowed, either with a mechanical assistance or under pressure generated in the electric heater 132, along one of the heat transfer pipelines 126 to the heat exchanger 134 where the heated gas stream 136 transfers thermal energy to the fluidization gas stream 107 flowing through the heat exchanger 134. The fluidization gas stream 107 is consequently heated in the heat exchanger 134 to, or above, the calcination temperature for the solid carbonate material 101 to form a heated fluidization gas stream 107 which flows via the fluidization gas inlet 114F into the interior 112 of the reactor 110 to fluidize the bed 109 of the solid carbonate material 101 and to calcine the solid carbonate material 101. The cooled gas stream 136 flows from the heat exchanger 134 via another one of the heat transfer pipelines 126 back to the electric heater 132, where it can re-acquire thermal energy. In the configuration of FIG. 1, the heat exchanger 134 is upstream of the fluidization gas inlet 114F, as per the flow direction of the fluidization gas stream 107.

[0077] The heating system 130 and its electric heater 132 allow the calciner 110 to use the same gas flow (i.e., the fluidization gas stream 107) to achieve the dual function of fluidizing the bed 109 of the solid carbonate material 101 and calcining the solid carbonate material 101. The calciner 110 may thus be referred to as an “electric calciner,” because the heat required for calcination is provided by electrical energy, via the fluidization gas stream 107. The carbon intensity associated with the calcination of the solid carbonate material 101 may thus be reduced compared to calcination processes where it is necessary to combust hydrocarbons to generate the thermal energy needed for calcination and to generate the gases needed for fluidization. In configurations of this disclosure where the electricity provided to the electric heater 132 comes from renewable or low-carbon sources (e.g., photovoltaic energy, wind energy, hydroelectric energy, nuclear energy, etc.), the carbon intensity associated with the calcination of the solid carbonate material 101 is reduced compared to a calcination process which combusts hydrocarbons to generate the thermal energy required for reacting the carbonate material. Indeed, in configurations of this disclosure where the electricity provided to the electric heater 132 comes from renewable or low-carbon sources (e.g., photovoltaic energy, wind energy, hydroelectric energy, nuclear energy, etc.), the carbon intensity associated with the calcination of the solid carbonate material 101 may be eliminated.

[0078] An example configuration of the heating system 130 is provided in FIG. 2 A. The heating system 130 includes an electric power supply line 131 to deliver the electrical energy required by the electric heater 132. The electric power supply line 131 may emanate from the electrical source 135 to provide the electrical energy to the electric heater 132. Electrical energy from the electric power supply line 131 is used to heat a core 133 of the electrical heater 132 to high temperatures. The core 133 may be surrounded by insulation within the body of the electric heater 132 to reduce heat loss and help preserve high temperatures for the core 133. The circulating gas stream 136 flows through one of the heat transfer pipelines 126 toward the hot core 133. In the configuration of the heating system 130 of FIG. 2A, the heating system 130 includes a blower 138 to circulate the circulating gas stream 136 through both heat transfer pipelines 126. The circulating gas stream 136 is heated by the core 133 to gas temperatures higher than the calcination temperature, and the heated gas stream 136 flows through the other heat transfer pipeline 126 to the heat exchanger 134.

[0079] In the heat exchanger 134, the heated gas stream 136 transfers thermal energy to the fluidization gas stream 107, raising the temperature of the fluidization gas stream 107 to, or above, the calcination temperature. The heated fluidization gas stream 107 flows from the heat exchanger 134 through the fluidization pipeline 124 to the fluidization gas inlet 114F of the reactor 110. An example of the heating system 130 may be, or may include, the TEMS™ heating unit provided by Kelvin Thermal Energy, Inc. of Toronto, Ontario, Canada. Other configurations of the heating system 130 are possible. For example, the heating system 130 of FIG. 2A may not include the heat exchanger 134, such that the fluidization gas stream 107 is sent, via the heat transfer pipelines 126, to circulate around the hot core 133 to acquire thermal energy therefrom, and then sent to the fluidization gas inlet 114F. In such a configuration, the heating system 130 operates on the principle of solid-to-gas heat transfer. In the configuration of FIG. 2A, the circulating gas stream 136 being heated by the core 133 is pure nitrogen (N2), such that the circulating gas stream 136 is substantially or entirely free of elements which may impact the material integrity of the heat transfer pipelines 126. In another configuration of the heating system 130, the circulating gas stream 136 may include one or more of another inert gas stream, such as argon. In another configuration of the heating system 130, the circulating gas stream 136 may include an air stream.

[0080] An example of another possible configuration of the heating system 830 is provided in FIG. 2B. The heating system 830 includes an electric power supply line 831 to deliver the electrical energy required by an electric heater 832. The electric power supply line 831 may emanate from an electrical source 835 to provide the electrical energy to the electric heater 832. The electrical heater 832 has one or more electrical heating elements 837 and a heat-retaining core 833. The electrical heating elements 837 are encased within the heat- retaining core 833, or are otherwise positioned relative to the heat-retaining core 833 so that heat generated by the electrical heating elements 837 is captured and stored by the heat-retaining core 833. The heat-retaining core 833 may be made of a heat- retaining material, such as a ceramic material and more particularly brick.

[0081] An electric potential from the electric power supply line 831 is applied to the electrical heating elements 837. In the electric heater 832 of FIG. 2B, the electrical heating elements 837 are electrical resistance heating elements 837, such that the electric current from the electric power supply line 831 that is passed through the electrical heating elements 837 generates heat from resistance elements of the electrical heating elements 837. The heat generated by the electrical heating elements 837 is transferred to the heat-retaining core 833 of the electrical heater 832 to heat the heat-retaining core 833 to high temperatures, for example above 1000°C. The heatretaining core 833 may be surrounded by insulation within the body of the electric heater 832 to reduce heat loss and help preserve high temperatures for the heat-retaining core 833. A blower 838 of the heating system 830 flows the fluidization gas stream 107 from the fluidization pipeline 124 through one of the heat transfer pipelines 826 toward the hot heat-retaining core 833. Heat is transferred to the fluidization gas stream 107 from the heat-retaining core 833, such that the fluidization gas stream 107 is heated by the heat-retaining core 833 to gas temperatures higher than the calcination temperature. In such a configuration, the electric heater 832 operates on the principle of solid- to-gas heat transfer. The heated fluidization gas stream 107 flows through the other heat transfer pipeline 126, through the fluidization pipeline 124, and then into the reactor 110 to fluidize the bed 109 of solid carbonate material 101 and to calcinate the solid carbonate material 101. An example of the heating system 830 may be, or may include, the Rondo Heat Battery provided by Rondo Energy of California, USA. Other configurations of the heating system 830 are possible. For example, in another possible configuration, a circulating fluid absorbs heat from the hot heat-retaining core 833 and transfers the heat to the fluidization gas stream 107 via a heat exchanger. In another possible configuration, the heating system 830 includes multiple electric heaters 832 arranged as a train or as a bank of electric heaters 832, which transfer their collective thermal energy output to the fluidization gas stream 107.

[0082] In another possible configuration of the heating system 130, the heating system 130 includes multiple electric heaters 132 which may be arranged with multiple heat exchangers 134 in a parallel or series heat transfer arrangement, such that their collective thermal energy output is provided to the fluidization gas stream 107. An example of a heating system 930 in such a series heat transfer arrangement is provided with reference to FIG. 2C. Referring to FIG. 2C, the heating system 930 includes multiple electric heaters 132. Each electric heater 132 is paired with a heat exchanger 134 via a dedicated set of heat transfer pipelines 126. The heating system 930 includes an electric power supply line 131 to deliver the electrical energy required by the plurality of electric heaters 132. Electrical energy from the electric power supply line 131 is used to heat the core 133 of each of the electrical heaters 132 to high temperatures. In the configuration of the heating system 930 of FIG. 2C, each pairing of electric heater 132 and heat exchanger 134 includes a blower 138 to circulate the circulating gas stream 136 through both heat transfer pipelines 126. The circulating gas stream 136 is heated by each core 133, and the heated gas stream 136 flows through the other heat transfer pipeline 126 to the heat exchanger 134 paired with each electric heater 132. In each heat exchanger 134, the heated gas stream 136 transfers thermal energy to the fluidization gas stream 107, raising the temperature of the fluidization gas stream 107. The heated fluidization gas stream 107 flows along the fluidization pipeline 124 from one heat exchanger 134 to the next sequential heat exchanger 134. From the last heat exchanger 134 in series, the fluidization gas stream 107 flows through the fluidization pipeline 124 to the fluidization gas inlet 114F of the reactor 110. The series heat transfer arrangement of heat exchangers 134 and electric heaters 132 of FIG. 2C allows for the last heat exchanger 134 and electric heater 132 in series to heat the fluidization gas stream 107 to, or above, the calcination temperature, before flowing into the reactor 110. The series heat transfer arrangement of FIG. 2C allows for the electric heaters 132 to collectively output thermal energy to the fluidization gas stream 107, which may help to reduce the thermal load on each electric heater 132 individually because each electric heater 132 may only need to provide some of the thermal energy required to heat the fluidization gas stream 107 to, or above, the calcination temperature. Other configurations of the series heat transfer arrangement of FIG. 2C are possible. For example, the heating system 930 of FIG. 2C may not include heat exchangers 134, such that the fluidization gas stream 107 is sent, via the heat transfer pipelines 126, to circulate around the hot cores 133 of each of the electric heaters 132 in series to acquire thermal energy therefrom, and then sent to the fluidization gas inlet 114F. In such a configuration, the heating system 930 operates on the principle of solid-to-gas heat transfer. The description, features, reference numbers and advantages of the heating system 130,830 provided in relation to FIGS. 1 to 2B apply mutatis mutandis to the heating system 930 of FIG. 2C.

[0083] An example of a heating system 730 in a parallel heat transfer arrangement is provided with reference to FIG. 2D. Referring to FIG. 2D, the heating system 730 includes multiple electric heaters 132. Each electric heater 132 is paired with a heat exchanger 134 via a dedicated set of heat transfer pipelines 126. Electrical energy is used to heat the core 133 of each of the electrical heaters 132 to high temperatures. Each pairing of electric heater 132 and heat exchanger 134 may include a blower (as described above) to circulate the circulating gas stream 136 through both heat transfer pipelines 126. The circulating gas stream 136 is heated by each core 133, and the heated gas stream 136 flows through the other heat transfer pipeline 126 to the heat exchanger 134 paired with each electric heater 132. In the parallel heat transfer arrangement of FIG. 2D, the fluidization pipeline 124 divides into three fluidization pipeline segments 124A,124B,124C. The fluidization gas stream 107 therefore also divides into a maximum three portions each of which flows along one of the fluidization pipeline segments 124A,124B,124C. In each heat exchanger 134, the heated gas stream 136 transfers thermal energy to the corresponding portion of the fluidization gas stream 107, raising the temperature of that portion of the fluidization gas stream 107 to, or above, the calcination temperature. The heated portions of the fluidization gas stream 107 flow along their respective fluidization pipeline segments 124A,124B,124C and then recombine into the full fluidization gas stream 107 when the fluidization pipeline segments 124A,124B,124C merge downstream of the heat exchangers 134 into the fluidization pipeline 124. The merged fluidization gas stream 107 flows along the fluidization pipeline 124 to the fluidization gas inlet 114F of the reactor 110. The parallel heat transfer arrangement of FIG. 2D allows for each electric heater 132 to heat only a portion of the fluidization gas stream 107 to, or above, the calcination temperature, which may help to reduce the thermal load on each electric heater 132 individually. Other configurations of the parallel heat transfer arrangement of FIG. 2D are possible. For example, the heating system 730 of FIG. 2D may not include heat exchangers 134, such that the portions of the fluidization gas stream 107 are sent, via the heat transfer pipelines 126, to circulate around the hot cores 133 of each of the electric heaters 132 in parallel to acquire thermal energy therefrom, and then sent to the fluidization gas inlet 114F. In such a configuration, the heating system 730 operates on the principle of solid-to-gas heat transfer. The description, features, reference numbers and advantages of the heating system 130,830,930 provided in relation to FIGS. 1 to 2C apply mutatis mutandis to the heating system 730 of FIG. 2D. FIG. 2D shows three fluidization pipeline segments 124A,124B,124C. More or fewer fluidization pipeline segments 124A,124B,124C are possible. The heating system 130,830,930,730 may include electric heaters 132, 832 and heat exchangers 134 arranged in a combination of a series heat transfer arrangement and a parallel heat transfer arrangement.

[0084] In other possible configurations of the calciner 110, and as explained above, the heating system 130 is a component or feature of the calciner 110 itself, rather than a system separate from the calciner 110, as depicted in FIG. 1. FIG. 3 provides an example of such an electric calciner 210 configuration (alternatively referred to herein as reactor 210), in which a heating system 230 is mounted directly to, or is integral with, the body of the reactor 210. The fluidization gas stream 107 flows along the fluidization pipeline 124 and then through an electric heater 232. The electric heater 232 heats the circulating gas stream 236, and the heated circulating gas stream 236 transfers heat to the fluidization gas stream 107. In such a configuration, the electric heater 232 functions as a gas-to-gas heat exchanger, in which a hot core 233 transfers heat indirectly to the fluidization gas stream 107. The description, features, reference numbers and advantages of the calciner 110 and of the heating system 130, 830 provided in relation to FIGS. 1 to 2A apply mutatis mutandis to the calciner 210 and to the heating system 230 of FIG. 3. [0085] In configurations of the disclosure, and as explained above, the fluidization gas stream 107 may be composed of some of the exhaust gas stream 108 from the reactor 110. For example, and referring to FIG. 4, the piping network 120 includes a recycle pipeline 128. The recycle pipeline 128 allows for the exhaust gas stream 108 from the exhaust gas outlet 116E of the reactor 110 to be split into two gas streams: a recycle gas stream 108R and a product gas stream 108P. The recycle gas stream 108R of the exhaust gas stream 108 flows to the fluidization gas inlet 114F via the recycle pipeline 128, such that this portion of the exhaust gas stream 108 is recycled to form the fluidization gas stream 107. A remainder of the exhaust gas stream 108, i.e. the product gas stream 108P, is discharged as a product of the reactor 110 and treated accordingly. The ratio of the recycle gas stream 108R to the product gas stream 108P can vary depending on the operating requirements of the reactor 110. For example, in implementations where the fluidization gas stream 107 is composed almost entirely of the recycle gas stream 108R (e.g., the concentration of CO2 in the fluidization gas stream 107 is at least at least 90% v/v, or between 90% and 99.9% v/v), the recycle gas stream 108R has a greater mass flow rate of CO2 (unit of mass/unit of time) than the product gas stream 108P. In such implementations, at least 50% of the CO2 present in the exhaust gas stream 108 can be flowed as part of the recycle gas stream 108Rto form the fluidization gas stream 107. In another of such implementations, at least 70% of the CO2 present in the exhaust gas stream 108 can be flowed as part of the recycle gas stream 108Rto form the fluidization gas stream 107. The volumetric flow rate (unit of volume/unit of time) or the mass flow rate of the recycle gas stream 108R may be determined based on a desired fluidization velocity needed to fluidize the bed 109 of the solid carbonate material 101, using iterations based on varying the CO2 present in the recycle gas stream 108R. The recycle gas stream 108R may be considered a “slipstream” of the exhaust gas stream 108, such that the recycle pipeline 128 is a “take-off’ line from the main exhaust gas pipeline 121. In configurations of the present disclosure, both the recycle and product gas streams 108R, 108P include CO2 from the CO2 gas stream 105.

[0086] Dividing the flow of exhaust gas stream 108 into the recycle and product gas streams 108R, 108P may be achieved in different ways. For example, in the configuration of the calcination system 400 of FIG. 4, the recycle pipeline 128 is a series of interconnected piping segments coupled to, and extending between, a portion of the exhaust gas pipeline 121 and a portion of the fluidization pipeline 124. Separation of the recycle gas stream 108R from the product gas stream 108P occurs downstream of the exhaust gas outlet 116E in this configuration. 1 Separation of the recycle gas stream 108R from the product gas stream 108P occurs downstream of the one or more solid-gas separators (e.g., cyclones 113) in this configuration. The junction between the recycle pipeline 128 and the exhaust gas pipeline 121 may include any suitable flowcontrol device (valve, blower, flap, etc.) to control or deflect the flow of the exhaust gas stream 108. In another possible configuration for providing the recycle gas stream 108R, separation of the recycle gas stream 108R from the product gas stream 108P occurs at the reactor 110 itself, such that a portion of the hot exhaust gas stream 108 is recycled as the fluidization gas stream 107. [0087] The junction between the recycle pipeline 128 and the fluidization pipeline 124 may also include any suitable flow-control device (valve, flap, etc.) to control or deflect the exhaust gas stream 108. For example, and referring to FIG. 4, the junction between the recycle pipeline 128 and the fluidization pipeline 124 includes a blower 438 to flow the recycle gas stream 108R and convert it into the fluidization gas stream 107 by increasing its pressure until the fluidization gas stream 107 achieves a desired velocity, such as the fluidization velocity necessary to fluidize the bed 109 of the solid carbonate material 101. In other configurations, the blower 438 is not present because the recycle gas stream 108R discharged from the reactor 110 is at sufficient pressure to achieve the desired velocity of the fluidization gas stream 107. In other configurations, the blower 438 is not present and another flow movement device (e.g., compressor, venturi eductor, etc.) increases pressure until the fluidization gas stream 107 achieves a desired velocity. Non-limiting examples of fluidization velocities include between 2-9 ft/s. The fluidization velocity may be determined based on the rheology and particle size of the solid carbonate material 101, to name but two factors for determining the fluidization velocity.

[0088] Referring to FIG. 4, the composition of the recycle gas stream 108R and of the fluidization gas stream 107 is identical. Referring to FIG. 4, the exhaust gas stream 108 includes CO2 from the CO2 gas stream 105, such that some of the CO2 gas stream 105 circulates in a loop beginning with being present or composing the fluidization gas stream 107, then being discharged as the exhaust gas stream 108 and then forming part of the recycle gas stream 108R that becomes the fluidization gas stream 107. In such a configuration, the recycle gas stream 108R may be referred to as “fluidization CO2”. In such a configuration, the partial pressure of CO2 gas within the reactor 110 may substantially equal the total pressure of gases in the reactor 110. Thus, the calcination temperature for the solid oxide material 103 in such an environment may be higher than the calcination temperature in environments with lower partial pressures of CO2 gas, such as environments where steam is used with CO2 gas to fluidize the bed 109 of the solid carbonate material 101, as described in greater detail below. The calcination temperature and the partial pressure of CO2 gas within the reactor 110 have a direct relationship, in that higher calcination temperatures may be required for higher partial pressures of CO2 gas within the reactor 110 [0089] Discharging some of the exhaust gas stream 108 as the product gas stream 108P while recycling a remainder of the exhaust gas stream 108 as the recycle gas stream 108R also allows for using a single gas stream (e.g., CO2 from the CO2 gas stream 105) for the purposes of both fluidizing the bed 109 of the solid carbonate material 101 and transferring thermal energy from the heating system 130 to the bed 109 of the solid carbonate material 101 to calcine the solid carbonate material 101. In other possible configurations, the recycle gas stream 108R is mixed with a separate stream of the fluidization gas stream 107 before being heated by the heating system 130, such that the composition of the recycle gas stream 108R and of the fluidization gas stream 107 is not identical prior to mixing. In other configurations, such as shown in FIG. 1, the reactor 110 is a “flow through” body in which no portion of the fluidization gas stream 107 is recycled from the exhaust gas stream 108. The description, features, reference numbers and advantages of the calcination system 100 provided in relation to FIGS. 1 apply mutatis mutandis to the calcination system 400 of FIG. 4.

[0090] FIG. 5 shows another configuration of the disclosure in which the fluidization gas stream 107 is composed of some of the exhaust gas stream 108 from the reactor 110. The calcination system 500 of FIG. 5 includes a pre-heater heat exchanger 540 for preheating the solid carbonate material 101 before it is provided to the reactor 110. The pre-heater heat exchanger 540 transfers heat from the hot exhaust gas stream 108 discharged from the exhaust gas outlet 116E to the solid carbonate material 101, to heat the solid carbonate material 101 and produce a cooled exhaust gas stream 108C (e.g., a cooled CO2 gas stream 108C). The piping network 120 of the calcination system 500 includes a first pipeline 123A for moving the solid carbonate material 101 from the pre-heater heat exchanger 540 to the solids inlet 114S. The piping network 120 includes a second pipeline 123B for flowing the hot exhaust gas stream 108 from the exhaust gas outlet 116E to the pre-heater heat exchanger 540. The pre-heater heat exchanger 540 is thus thermally coupled to the solids inlet 114S via the first pipeline 123 A and is thermally coupled to the exhaust gas outlet 116E via the second pipeline 123B. The pre-heater heat exchanger 540 of FIG. 5 is positioned downstream of the one or more solid-gas separators (e.g., cyclones 113). The pre- heater heat exchanger 540 of FIG. 5 is a gas-to-solid heat exchanger and pre-heats and/or dries the solid carbonate material 101 (e.g., CaCCh) before it enters the calciner 110.

[0091] In some configurations, the solid carbonate material 101 may have water content. This may result, for example, from the solid carbonate material 101 being washed upstream of the reactor 110 to remove an aqueous solution from the solid carbonate material 101 prior to calcination. In such configurations, the water may make up a not insignificant portion of material fed to the solids inlet 114S (e.g., up to 10 wt%), such that it may be desirable to remove the water content from the solid carbonate material 101 before it is calcined in the reactor 110. Referring to FIG. 5, in configurations where the solid carbonate material 101 has water content, the heat applied to the solid carbonate material 101 in the pre-heater heat exchanger 540 may generate steam. In the configuration of FIG. 5, the steam is discharged from the pre-heater heat exchanger 540 with the cooled exhaust gas stream 108C. It may be desirable to remove the steam content from the cooled exhaust gas stream 108C before some of the cooled exhaust gas stream 108C is provided as the recycle gas stream 108R. Therefore, the calcination system 500 of FIG. 5 includes a water knock-out unit 550, such as a condenser, a scrubber, and/or a quench tower, which is thermally coupled to the pre-heater heat exchanger 540. The water knock-out unit 550 receives the cooled exhaust gas stream 108C with steam content from the pre-heater heat exchanger 540 via a condenser pipeline 125 of the piping network 120. The water knock-out unit 550 is configured to condense water vapor from the cooled exhaust gas stream 108C to produce a dry exhaust gas stream 108D (e.g., a reduced- water-content cooled CO2 gas stream 108D). The water content of the dry exhaust gas stream 108D may be close to zero, and is less than the water content of the cooled exhaust gas stream 108C. The condensed water 542 may be discharged from the water knock-out unit 550, and may be reused, sent for treatment and disposal, or sent for storage. The dry exhaust gas stream 108D includes the CO2 gas stream 105, is divided into the recycle and product gas streams 108R, 108P as described above. The water knock-out unit 550 is fluidly coupled to the recycle pipeline 128 and disposed upstream of the fluidization gas inlet 114F, relative to the flow direction of the fluidization gas stream 107. Thus, in the configuration of the calcination system 500 of FIG. 5, the fluidization gas stream 107, 108R (e.g., CO2) is recycled from downstream of the calciner exhaust water knock-out unit 550. It may be desirable for the recycle gas stream 108R to have water because its presence in the recycle gas stream 108R may reduce the partial pressure of CO2 in the interior 112 of the reactor 110, in comparison to a reactor 110 in which primarily CO2 gas is present.

[0092] The water knock-out unit 550 is optional and may not be present in all configurations of the calcination system 100, 400, 500. For example, in other configurations of the calcination system 100, 400, 500, it may not be necessary for water content to be removed from the exhaust gas stream 108, such that no water knock-out unit 550 is present and the recycle stream 108R sent to fluidize the bed 109 of the solid carbonate material 101 contains water content. In another configuration of the calcination system 100, 400, 500 where the pre-heater heat exchanger 540 generates little or no steam because the solid carbonate material 101 has little or no water content (possibly because it was dried before arriving at the pre-heater heat exchanger 540), the water knock-out unit 550 may not be necessary and a portion of the cooled exhaust gas stream 108C may be directed to the fluidization gas inlet 114F as the recycle gas stream 108R. In another configuration of the calcination system 100, 400, 500 where the pre-heater heat exchanger 540 generates steam in manageable quantities, the water knock-out unit 550 may not be necessary and a portion of the cooled exhaust gas stream 108C with steam may be directed to the fluidization gas inlet 114F as the recycle gas stream 108R. In yet configuration of the calcination system 100, 400, 500 where the pre-heater heat exchanger 540 has a separate outlet for steam such that steam is discharged separately from the cooled exhaust gas stream 108C, the water knock-out unit 550 may not be necessary and a portion of the cooled exhaust gas stream 108C may be directed to the fluidization gas inlet 114F as the recycle gas stream 108R. In such configurations where a portion of the cooled exhaust gas stream 108C is directed to the fluidization gas inlet 114F as the recycle gas stream 108R, the cooled exhaust gas stream 108C may be flowed to the recycle pipeline 128 via a cooled exhaust recycle pipeline 128C fluidly coupling the pre-heater heat exchanger 540 and the recycle pipeline 128 (see FIG. 5). In such configurations, the recycle CO2 is pulled from the pre-heater heat exchanger 540. The description, features, reference numbers and advantages of the calcination systems 100, 400 depicted in FIGS. 1 and 4, respectively, apply mutatis mutandis to the calcination system 500 of FIG. 5.

[0093] In view of the present disclosure, it will be appreciated that the CO2 for the recycle gas stream 108R may be drawn from different units and locations of the calcination system 100, 400, 500 including, but not limited to, the calciner 110, the water knock-out unit 550 and the preheater heat exchanger 540. [0094] In some configurations of the calcination system, it may be desirable to use another gas stream which, in combination with the fluidization gas stream 107, helps to fluidize the bed 109 of the solid carbonate material 101. This may reduce the volume of the fluidization gas stream 107 that needs to be heated to the calcination temperature by the heating system 130, 230. The size of the blower 438 that is required to flow the fluidization gas 107 can therefore be reduced. Also, the energy consumption of the heating system 130, 230 can be reduced. One such configuration of the calcination system 600 is shown in FIG. 6, in which a steam stream 662 is used, in combination with the fluidization gas stream 107, to fluidize the bed 109 of the solid carbonate material 101. The calcination system 600 includes a steam heat exchanger 660 which is fluidly coupled to the solids discharge pipeline 127 and is also fluidly coupled to a fluid source 664 configured to provide water or steam to the steam heat exchanger 660. Example fluid sources include, but are not limited to, a boiler or water tank. Hot solid oxide material 103 is discharged from a reactor 610 (or “calciner 610”) of calcination system 600 and conveyed from the solids outlet 116S of the reactor 610 to the steam heat exchanger 660 via the solids discharge pipeline 127. Water or steam from the fluid source 664 is sent to the steam heat exchanger 660. In the steam heat exchanger 660, heat from the hot solid oxide material 103 is transferred to the water or steam to generate the solids-heated steam stream 662 and a cooled solid oxide material 103. The fluidization pipeline 124 includes a blower 638 to flow the fluidization gas stream 107 by increasing its pressure until the fluidization gas stream 107 achieves a desired velocity, such as the fluidization velocity necessary to fluidize the bed 109 of the solid carbonate material 101.

[0095] Since it functions to cool the solid oxide material 103, the steam heat exchanger 660 may be referred to as a “lime cooler” in configurations where the solid oxide material 103 includes, or is, solid CaO. The inlets 114 of the reactor 610 of FIG. 6 include a steam inlet 614S. The steam inlet 614S is located toward a bottom of the body of the reactor 610 and below the distributor plate 118 of the reactor 610, such that the steam stream 662, which enters the interior 112 of the reactor 610 via the steam inlet 614S, will help to fluidize the bed 109 of the solid carbonate material 101. The steam inlet 614S is spaced apart and separate from the fluidization gas inlet 114F in the configuration of FIG. 6. The piping network 120 of the calcination system 600 of FIG. 6 includes a steam pipeline 629 extending between a steam discharge of the steam heat exchanger 660 and the steam inlet 614S, to flow the steam stream 662 to the steam inlet 614S. In some configurations, the steam pipeline 629 includes, or is fluidly coupled to, a blower, compressor, fan or other gas-moving device to pressurize the steam stream 662 to achieve a desired fluidization velocity. Although the steam inlet 614S and the fluidization gas inlet 114F are shown as distinct and separated from each other in FIG. 6, in other configurations the steam stream 662 and the fluidization gas stream 107 may enter the reactor 610 via the same inlet. The description, features, reference numbers and advantages of the calcination systems 100, 400, 500 depicted in to FIGS. 1, 4, and 5, respectively, apply mutatis mutandis to the calcination system 600 of FIG. 6. [0096] FIG. 7 depicts another example calcination system 700 FIG. in which another gas stream (i.e., steam stream 662) is used in combination with the fluidization gas stream 107 to fluidize the bed 109 of the solid carbonate material 101. The steam heat exchanger 660 is fluidly coupled to the solids discharge pipeline 127 and is also fluidly coupled to the fluid source 664. Heat from the hot solid oxide material 103 is transferred to water or steam provided by the fluid source 664 to generate the steam stream 662 and to form cooled solid oxide material 103. The steam pipeline 629 extends between a steam discharge of the steam heat exchanger 660 and the fluidization pipeline 124, so that the steam stream 662 flows into the fluidization pipeline 124 to mix with the fluidization gas stream 107 at a location that is upstream of the heat exchanger 134. In some configurations, the steam pipeline 629 includes, or is fluidly coupled to, a blower, compressor, fan or other gas-moving device to pressurize the steam stream 662 before mixing with the fluidization gas stream 107. A mixed gas stream 107M is formed from mixing the steam stream 662 and the fluidization gas stream 107. The fluidization pipeline 124 includes a blower 738 to flow the fluidization gas stream 107 and the mixed gas stream 107M by increasing their pressure until they achieve a desired velocity, such as the fluidization velocity necessary to fluidize the bed 109 of the solid carbonate material 101. The mixed gas stream 107M flows to the heat exchanger 134 to be heated to a temperature at or above the calcination temperature, and then flows to the fluidization gas inlet 114F to fluidize the bed 109 of the solid carbonate material 101 and calcine the solid carbonate material 101. For a given electrical power supply, and therefore a given amount of generated heat, the electric heater 132 may transfer less heat to the lower- volume fluidization gas stream 107 in FIG. 6 compared to the higher-volume mixed gas stream 107M of FIG. 7, such that the electric heater 132 may run hotter in the calcination system 600 of FIG. 6 than in the calcination system 700 of FIG. 7. Thus, the calcination systems 600, 700 of FIGS. 6 and 7 each allow for a reduction in the volume of the fluidization gas stream 107 that needs to be heated to the calcination temperature by relying on the steam stream 662 to make up the difference in gas flow required for fluidization, and the calcination system 700 of FIG. 7 may help to also reduce the thermal load on the electric heater 132. The calcination systems 600, 700 of FIGS. 6 and 7 may both allow for reducing the temperature at which calcination occurs in the reactor 110 (i.e., the calcination temperature) because the presence of the steam stream 662 reduces the partial pressure of CO2 in the interior 112 of the reactor 110, in comparison to a reactor 110 in which primarily CO2 gas is present.

[0097] In the configurations of FIGS. 6 and 7, the fluidization gas stream 107 works with, or comprises, steam. In possible configurations of steam fluidization, water and/or steam may be added directly to the fluidization pipeline 124 to mix with the fluidization gas stream 107 upstream of the heat exchanger 134 or downstream of the heat exchanger 134. In configurations of the calcination system 600, 700 where part of the exhaust gas stream 108 is recycled to form part of the fluidization gas stream 107, the calcination system 600, 700 may include a water-knock out unit to remove water from the exhaust gas stream 108 before part of it is recycled. The description, features, reference numbers and advantages of the calcination systems 100, 400, 500, 600 depicted in FIGS. 1, 4, 5, and 6, respectively, apply mutatis mutandis to the calcination system 700 of FIG. 7.

[0098] In some configurations of the calcination systems 100, 400, 500, 600 it may be desirable to recover heat from the hot solid oxide product 103 into the fluidization gas stream 107, which may allow for reducing both the duty of the electric heater 132 and its operating temperature. FIG. 8 depicts an example calcination system 650in which a solids cooler 652 is used to transfer thermal energy from the solid oxide material 103 to the fluidization gas stream 107 before the fluidization gas stream 107 is further heated in the heat exchanger 134 to, or above, the calcination temperature. Since the solids cooler 652 functions to cool the solid oxide material 103, the solids cooler 652 may be referred to as a “lime cooler” in configurations where the solid oxide material 103 includes, or is, solid CaO. The fluidization pipeline 124 is fluidly coupled to the solids cooler 652 to flow the fluidization gas stream 107 to the solids cooler 652. The solids discharge pipeline 127 extends from the solids outlet 116S to the solids cooler 652, allowing the hot solid oxide material 103 to be moved to the solids cooler 652 where it transfers thermal energy to the fluidization gas stream 107. To reduce or prevent the solid oxide material 103 from re-carbonating due to the presence of CO2 in the fluidization gas stream 107, the solids cooler 652 may allow for indirect heat exchange between the solid oxide material 103 and the fluidization gas stream 107, such that the two streams are prevented from mixing in the solids cooler 652. If desired, some of the exhaust gas stream 108 may be recycled back to the reactor 110, as described above. The description, features, reference numbers and advantages of the calcination systems 100, 400, 500, 600, 700 depicted in FIGS. 1, 4, 5, 6, and7, respectively, apply mutatis mutandis to the calcination system 650 of FIG. 8.

[0099] Referring to FIG. 9, a method 800 of calcining solid carbonate material is disclosed. At 802, the method 800 includes providing solid carbonate material (e.g., solid carbonate material 101) to a reactor (e.g., reactor 110, 210, 610) to form a bed of the solid carbonate material (e.g., bed 109). At 804, the method includes heating a circulating gas stream (e.g., gas stream 136) with an electric heater (e.g., electric heaters 132, 232). At 806, the method 800 includes transferring heat from the circulating gas stream to a fluidization gas stream (e.g., fluidization gas stream 107) to form a heated fluidization gas stream at a calcination temperature for the solid carbonate material. At 808, the method 800 includes flowing the heated fluidization gas stream through the bed of the solid carbonate material in the reactor to fluidize the bed of the solid carbonate material, and to calcine the solid carbonate material to form a carbon dioxide (CO2) gas stream (e.g., gas stream 105) and a solid oxide material (e.g., solid oxide material 103). At 810, the method 800 includes discharging at least some of the CO2 gas stream and at least some of the solid oxide material from the reactor.

[00100] Referring to FIG. 10, in some implementations, the calcination system 100, 400, 500, 600, 700, 650 with the calciner 110, 210, 610 is part of a direct-air-capture (DAC) system 9100 for capturing CO2 directly from atmospheric air, according to one possible and non-limiting example of a use for the calcination system 100, 400, 500, 600, 700, 650 and/or the calciner 110, 210, 610. Concentrations of CO2 in the atmosphere are dilute, in that they are presently in the range of 400-420 parts per million (“ppm”) or approximately 0.04-0.042% v/v, and less than 1% v/v. These atmospheric concentrations of CO2 are at least one order of magnitude lower than the concentration of CO2 in point-source emissions, such as flue gases, where point-source emissions can have concentrations of CO2 ranging from 5-15% v/v depending on the source of emissions.

[00101] Referring to FIG. 10, a gas-liquid contactor 9200 absorbs some of the CCh from atmospheric air 1603 using a CO2 capture solution 9214 to form a CO2 rich solution 1602 and a stream of CCh-lean air 1609 (i.e., a stream of air in which the concentration of CO2 is less than that in the atmospheric air 1603). The CO2 rich solution 1602 flows from the gas-liquid contactor 9200 to a pellet reactor 9110 of the DAC system 9100. A slurry of calcium hydroxide 2104 is injected into the pellet reactor 9110. As Ca²⁺ reacts with CO^2- in the pellet reactor 9110, it drives dissociation of calcium hydroxide to return a stream of aqueous alkaline solution as the CO2 capture solution 9214, and to precipitate calcium carbonate (CaCCh) onto calcium carbonate particles in the pellet reactor 9110. Further processing of the calcium carbonate solids, including but not limited to filtering, washing, dewatering or drying, may occur prior to sending the calcium carbonate solids to downstream process units. A stream 9106 of calcium carbonate solids (i.e., the solid carbonate material 101) is transported from the pellet reactor 9110 to the calciner 110, 210, 610 of the DAC system 9100. The calciner 110, 210, 610 calcines the calcium carbonate of the stream 9106 from the pellet reactor 9110 to produce a stream of gaseous CO2 2108 (e.g., the exhaust gas stream 108) and a stream of calcium oxide (CaO) 2101 (e.g., the solid oxide material 103), by heating the fluidization gas 107 upstream of the calciner 110, 210, 610. Some of the stream of gaseous CO2 2108 is processed for sequestration or other uses, thereby removing some of the CCh from the atmospheric air 1603 processed in the gas-liquid contactor 9200, while a remainder of the stream of gaseous CO22108 may be recycled back to the calciner 110, 210, 610. The stream of calcium oxide (CaO) 2101 is slaked with water in a slaker 2130 of the DAC system 9100 to produce the slurry of calcium hydroxide 2104 that is provided to the pellet reactor 9110. The DAC system 9100 may include multiple gas-liquid contactors 9200, where each gas-liquid contactor 9200 forms a cell of a train/assembly of gas-liquid contactors 9200.

[00102] The calcination systems 100, 400, 500, 600, 700, 650 can also include a control system (or flow control system) (e.g., control system 999 of FIG. 4) that is integrated with and/or communicably coupled with one or more components of the calcination system 100, 400, 500, 600, 700, 650. For example, the process streams in the calcination system 100, 400, 500, 600, 700, 650 can be flowed using one or more flow control systems (e.g., control system 999) implemented throughout the calcination system 100, 400, 500, 600, 700, 650. A flow control system can include one or more flow pumps, fans, blowers, or solids conveyors to move the process streams, one or more flow pipes through which the process streams are flowed and one or more valves to regulate the flow of streams through the pipes. Each of the configurations described herein can include at least one variable frequency drive (VFD) coupled to a respective pump that is capable of controlling at least one liquid flow rate. In some implementations, liquid flow rates are controlled by at least one flow control valve. [00103] In some embodiments, a flow control system can be operated manually. For example, an operator can set a flow rate for each pump or transfer device and set valve open or close positions to regulate the flow of the process streams through the pipes in the flow control system. Once the operator has set the flow rates and the valve open or close positions for all flow control systems distributed across the system, the flow control system can flow the streams under constant flow conditions, for example, constant volumetric rate or other flow conditions. To change the flow conditions, the operator can manually operate the flow control system, for example, by changing the pump flow rate or the valve open or close position.

[00104] In some embodiments, a flow control system can be operated automatically. For example, the flow control system can be connected to a computer or control system (e.g., control system 999) to operate the flow control system. The control system can include a computer- readable medium storing instructions (such as flow control instructions and other instructions) executable by one or more processors to perform operations (such as flow control operations). An operator can set the flow rates and the valve open or close positions for all flow control systems distributed across the facility using the control system. In such embodiments, the operator can manually change the flow conditions by providing inputs through the control system. Also, in such embodiments, the control system can automatically (that is, without manual intervention) control one or more of the flow control systems, for example, using feedback systems connected to the control system. For example, a sensor (such as a pressure sensor, temperature sensor or other sensor) can be connected to a pipe through which a process stream flows. The sensor can monitor and provide a flow condition (such as a pressure, temperature, or other flow condition) of the process stream to the control system. In response to the flow condition exceeding a threshold (such as a threshold pressure value, a threshold temperature value, or other threshold value), the control system can automatically perform operations. For example, if the pressure or temperature in the pipe exceeds the threshold pressure value or the threshold temperature value, respectively, the control system can provide a signal to the pump to decrease a flow rate, a signal to open a valve to relieve the pressure, a signal to shut down process stream flow, or other signals.

[00105] FIG. 11 is a schematic diagram of a control system (or controller) 1500, which may be used for example with the calcination system 100, 400, 500, 600, 700, 650 and/or the calciner 110, 210, 610. The control system 1500 can be used for the operations described in association with any of the computer-implemented methods described previously, for example as or as part of the control system 999 or other controllers described herein.

[00106] The control system 1500 is intended to include various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The control system 1500 can also include mobile devices, such as personal digital assistants, cellular telephones, smartphones, and other similar computing devices. Additionally the system can include portable storage media, such as, Universal Serial Bus (USB) flash drives. For example, the USB flash drives may store operating systems and other applications. The USB flash drives can include input/output components, such as a wireless transmitter or USB connector that may be inserted into a USB port of another computing device.

[00107] The system 5100 includes a processor 510, a memory 520, a storage device 530, and an input/output device 1540. Each of the components 510, 520, 530, and 1540 are interconnected using a system bus 1550. The processor 510 is capable of processing instructions for execution within the control system 1500. The processor may be designed using any of a number of architectures. For example, the processor 510 may be a CISC (Complex Instruction Set Computers) processor, a RISC (Reduced Instruction Set Computer) processor, or a MISC (Minimal Instruction Set Computer) processor.

[00108] In one implementation, the processor 510 is a single-threaded processor. In some implementations, the processor 510 is a multi-threaded processor. The processor 510 is capable of processing instructions stored in the memory 520 or on the storage device 530 to display graphical information for a user interface on the input/output device 1540.

[00109] The memory 520 stores information within the control system 1500. In one implementation, the memory 520 is a computer-readable medium. In one implementation, the memory 520 is a volatile memory unit. In some implementations, the memory 520 is a non-volatile memory unit.

[00110] The storage device 530 is capable of providing mass storage for the control system 1500. In one implementation, the storage device 530 is a computer-readable medium. In various different implementations, the storage device 530 may be a floppy disk device, a hard disk device, an optical disk device, or a tape device. [00111] The input/output device 1540 provides input/output operations for the control system 1500. In one implementation, the input/output device 1540 includes a keyboard and/or pointing device. In some implementations, the input/output device 1540 includes a display unit for displaying graphical user interfaces.

[00112] Certain features described can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. The apparatus can be implemented in a computer program product tangibly embodied in an information carrier, e.g., in a machine-readable storage device for execution by a programmable processor; and method steps can be performed by a programmable processor executing a program of instructions to perform functions of the described implementations by operating on input data and generating output. The described features can be implemented advantageously in one or more computer programs that are executable on a programmable system including at least one programmable processor coupled to receive data and instructions from, and to transmit data and instructions to, a data storage system, at least one input device, and at least one output device. A computer program is a set of instructions that can be used, directly or indirectly, in a computer to perform a certain activity or bring about a certain result. A computer program can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[00113] Suitable processors for the execution of a program of instructions include, by way of example, both general and special purpose microprocessors, and the sole processor or one of multiple processors of any kind of computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memories for storing instructions and data. Generally, a computer will also include, or be operatively coupled to communicate with, one or more mass storage devices for storing data files; such devices include magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and optical disks. Storage devices suitable for tangibly embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, ASICs (applicationspecific integrated circuits).

[00114] To provide for interaction with a user, the features can be implemented on a computer having a display device such as a CRT (cathode ray tube) or LCD (liquid crystal display) monitor for displaying information to the user and a keyboard and a pointing device such as a mouse or a trackball by which the user can provide input to the computer. Additionally, such activities can be implemented via touchscreen flat-panel displays and other appropriate mechanisms.

[00115] The features can be implemented in a control system (such as control system 999) that includes a back-end component, such as a data server, or that includes a middleware component, such as an application server or an Internet server, or that includes a front-end component, such as a client computer having a graphical user interface or an Internet browser, or any combination of them. The components of the system can be connected by any form or medium of digital data communication such as a communication network. Examples of communication networks include a local area network (“LAN”), a wide area network (“WAN”), peer-to-peer networks (having ad-hoc or static members), grid computing infrastructures, and the Internet.

[00116] The term “couple” and variants of it such as “coupled,” “couples,” and “coupling” as used in this description is intended to include indirect and direct connections unless otherwise indicated. For example, if a first device is coupled to a second device, that coupling may be through a direct connection or through an indirect connection via other devices and connections. Similarly, if the first device is communicatively coupled to the second device, communication may be through a direct connection or through an indirect connection via other devices and connections. In particular, a fluid coupling means that a direct or indirect pathway is provided for a fluid to flow between two fluidly coupled devices. Also, a thermal coupling means that a direct or indirect pathway is provided for heat energy to flow between to thermally coupled devices.

[00117] While this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features specific to particular implementations s. Certain features that are described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[00118] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[00119] A number of embodiments of the disclosure have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other embodiments are within the scope of the following claims. Further modifications and alternative embodiments of various aspects will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only. It is to be understood that the forms shown and described herein are to be taken as examples of embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description. Changes may be made in the elements described herein without departing from the spirit and scope as described in the following claims.

Claims

WHAT IS CLAIMED IS:

1. A system, comprising: a reactor comprising an interior volume configured to calcine a solid carbonate material, the interior volume in communication with at least one inlet and at least one outlet, the at least one inlet comprising a solids inlet configured to provide the solid carbonate material to the interior volume to form a bed of the solid carbonate material and a fluidization gas inlet configured to provide a fluidization gas stream to fluidize the bed of the solid carbonate material, and the at least one outlet comprising a solids outlet configured to convey a solid oxide material from the interior volume and an exhaust gas outlet configured to convey an exhaust gas stream from the interior volume; a piping network comprising a fluidization pipeline configured to flow the fluidization gas stream to the fluidization gas inlet, and at least one heat transfer pipeline; and a heating system comprising at least one electric heater coupled to the at least one heat transfer pipeline and operable to heat a circulating gas stream, and at least one heat exchanger coupled to the at least one electric heater through the at least one heat transfer pipeline and to the fluidization pipeline, the at least one heat exchanger operable to transfer heat from the circulating gas stream to the fluidization gas stream to heat the fluidization gas stream to a calcination temperature for the solid carbonate material.

2. The system of claim 1, wherein: the piping network further comprises at least one preheater pipeline; and the system further comprising a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline.

3. The system of either one of claim 1 or 2, further comprising a blower in fluid communication with the fluidization gas inlet through the fluidization pipeline.

4. The system of any one of claims 1 to 3, wherein the fluidization gas stream comprises a CO2 gas stream.

5. The system of claim 1, wherein the piping network comprises a recycle pipeline in fluid communication with the exhaust gas outlet and with the fluidization pipeline.

6. The system of claim 5, wherein: the piping network comprises at least one preheater pipeline and a condenser pipeline; and the system further comprises: a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline; and a water knock-out unit fluidly coupled to the pre-heater heat exchanger through the condenser pipeline and configured to receive a cooled exhaust gas stream from the pre-heater heat exchanger, the water knock-out unit fluidly coupled to the recycle pipeline and to the fluidization gas inlet, the water knock-out unit operable to condense water vapor from the cooled exhaust gas stream.

7. The system of claim 5, wherein: the piping network comprises at least one preheater pipeline; and the system further comprises: a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline, the pre-heater heat exchanger configured to cool the exhaust gas stream and form a cooled exhaust gas stream and heated solid carbonate material; and the recycle pipeline in fluid communication with the pre-heater heat exchanger to flow at least part of the cooled exhaust gas stream to the fluidization gas inlet.

8. The system of claim 5, wherein: the piping network comprises at least one preheater pipeline and a condenser pipeline; and the system further comprises: a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline, the pre-heater heat exchanger configured to cool the exhaust gas stream and form a cooled exhaust gas stream and heated solid carbonate material; a water knock-out unit fluidly coupled to the pre-heater heat exchanger through the condenser pipeline and configured to receive the cooled exhaust gas stream from the pre-heater heat exchanger, the water knock-out unit operable to condense water vapor from the cooled exhaust gas stream to form a dry exhaust gas stream; and the water knock-out unit fluidly coupled to the recycle pipeline and to the fluidization gas inlet to flow the dry exhaust gas stream to the fluidization gas stream.

9. The system of any one of claims 1 to 8, wherein: the piping network comprises a solid discharge pipeline that extends from the solids outlet; the at least one inlet comprises a steam inlet; and the system further comprises a steam heat exchanger thermally coupled to the solid discharge pipeline and to a source of water, and fluidly coupled to the steam inlet, the steam heat exchanger operable to transfer heat from the solid oxide material to water to generate steam for the steam inlet.

10. The system of any one of claims 1 to 8, wherein: the piping network comprises a solid discharge pipeline that extends from the solids outlet; and the system further comprises a steam heat exchanger thermally coupled to the solid discharge pipeline and to a source of water, and fluidly coupled to the fluidization pipeline, the steam heat exchanger operable to transfer heat from the solid oxide material to water to generate steam for the fluidization pipeline.

11. The system of any one of claims 1 to 8, wherein: the piping network comprises a solid discharge pipeline that extends from the solids outlet; the system further comprises a solids cooler thermally coupled to the solid discharge pipeline and to the fluidization pipeline, the solids cooler positioned upstream of the heat exchanger and operable to transfer heat from the solid oxide material to the fluidization gas.

12. The system of any one of claims 1 to 11, wherein the circulating gas stream comprises nitrogen.

13. The system of any one of claims 1 to 12, wherein the solid carbonate material is solid calcium carbonate (CaCCh).

14. The system of any one of claims 1 to 13, wherein the at least one electric heater comprises a plurality of electric heaters and the at least one heat exchanger comprises a plurality of heat exchangers, each electric heater of the plurality of electric heaters arranged with a heat exchanger of the plurality of heat exchangers to form a parallel arrangement of electric heaters and heat exchangers, the parallel arrangement of electric heaters and heat exchangers operable to collectively heat the fluidization gas stream to the calcination temperature.

15. A method of calcining a solid carbonate material, the method comprising: providing the solid carbonate material to a reactor to form a bed of the solid carbonate material; heating a circulating gas stream with an electric heater; transferring heat from the circulating gas stream to a fluidization gas stream to form a heated fluidization gas stream at a calcination temperature for the solid carbonate material; flowing the heated fluidization gas stream through the bed of the solid carbonate material in the reactor to fluidize the bed of the solid carbonate material, and to calcine the solid carbonate material to form a carbon dioxide (CO2) gas stream and a solid oxide material; and discharging at least a portion of the CO2 gas stream and at least a portion of the solid oxide material from the reactor.

16. The method of claim 15, wherein: discharging the at least a portion of the CO2 gas stream comprises transferring heat from the CO2 gas stream to the solid carbonate material to form a heated solid carbonate material; and providing the solid carbonate material to the reactor comprises providing the heated solid carbonate material to the reactor.

17. The method of claim 15 or 16, wherein flowing the heated fluidization gas stream through the bed of the solid carbonate material comprises blowing the heated fluidization gas stream through the bed of the solid carbonate material in the reactor.

18. The method of any one of claims 15 to 17, wherein transferring heat from the circulating gas stream to the fluidization gas stream to form the heated fluidization gas stream comprises transferring heat from the circulating gas stream to the at least a portion of the CO2 gas stream discharged from the reactor to form a heated CO2 fluidization gas stream.

19. The method of claim 15, wherein: providing the solid carbonate material to the reactor comprises providing the solid carbonate material with water content to a heat exchanger; and the method further comprises: in the heat exchanger, transferring heat from the CO2 gas stream discharged from the reactor to the solid carbonate material with the water content to form a heated solid carbonate material, a cooled CO2 gas stream, and a steam stream; providing the heated solid carbonate material to the reactor; and discharging the cooled CO2 gas stream and the steam stream from the heat exchanger.

20. The method of claim 15, wherein: providing the solid carbonate material to the reactor comprises providing the solid carbonate material to a heat exchanger; and the method further comprises: in the heat exchanger, transferring heat from the CO2 gas stream discharged from the reactor to the solid carbonate material to form a heated solid carbonate material and a cooled CO2 gas stream; providing the heated solid carbonate material to the reactor; and discharging the cooled CO2 gas stream from the heat exchanger; and wherein transferring heat from the circulating gas stream to the fluidization gas stream to form the heated fluidization gas stream comprises transferring heat from the circulating gas stream to at least a portion of the cooled CO2 gas stream to form a heated CO2 fluidization gas stream.

21. The method of claim 19, wherein transferring heat from the circulating gas stream to the fluidization gas stream to form the heated fluidization gas stream comprises transferring heat from the circulating gas stream to at least a portion of the cooled CO2 gas stream to form a heated CO2 fluidization gas stream.

22. The method of claim 21, wherein: discharging the cooled CO2 gas stream and the steam stream from the heat exchanger comprises discharging a mixed gas stream including the cooled CO2 gas stream and the steam stream from the heat exchanger; and the method further comprises condensing steam from the mixed gas stream to form a reduced-water-content cooled CO2 gas stream; wherein transferring heat from the circulating gas stream to the fluidization gas stream to form the heated fluidization gas stream comprises transferring heat from the circulating gas stream to at least a portion of the reduced- water- content cooled CO2 gas stream to form a heated CO2 fluidization gas stream.

23. The method of any one of claims 15 to 22, wherein: discharging the at least a portion of the CO2 gas stream and the at least a portion of the solid oxide material from the reactor comprises transferring heat from the at least a portion of the solid oxide material to a water stream to form a solids-heated steam stream; and the method further comprises flowing the solids-heated steam stream through the bed of the solid carbonate material in the reactor to fluidize the bed of the solid carbonate material.

24. The method of any one of claims 15 to 18, wherein: discharging the at least a portion of the CO2 gas stream and the at least a portion of the solid oxide material from the reactor comprises transferring heat from the at least a portion of the solid oxide material to a water stream to form a solids-heated steam stream; and flowing the heated fluidization gas stream through the bed of the solid carbonate material in the reactor to fluidize the bed of the solid carbonate material comprises flowing the heated fluidization gas stream and the solids-heated steam stream through the bed of the solid carbonate material in the reactor to fluidize the bed of the solid carbonate material.

25. The method of any one of claims 15 to 24, wherein heating the circulating gas stream with the electric heater comprises heating a nitrogen circulating gas stream with the electric heater.

26. The method of any one of claims 15 to 25, wherein providing the solid carbonate material to the reactor comprises providing solid calcium carbonate (CaCCh) to the reactor.

27. The method of claim 15, wherein discharging the at least a portion of the CO2 gas stream and the at least a portion of the solid oxide material from the reactor comprises: transferring heat from the at least a portion of the solid oxide material to the fluidization gas stream; and transferring heat from the circulating gas stream to the fluidization gas stream to form the heated fluidization gas stream at the calcination temperature.

28. The method of any one of claims 15 to 25, wherein providing the solid carbonate material to the reactor comprises providing solid calcium carbonate (CaCCh) to the reactor.

29. The method of claim 15, wherein flowing the heated fluidization gas stream through the bed of the solid carbonate material in the reactor comprises flowing a heated CO2 fluidization gas stream through the bed of the solid carbonate material in the reactor to fluidize the bed of the solid carbonate material, and to calcine the solid carbonate material to form the CO2 gas stream and the solid oxide material.

30. A system for capturing carbon dioxide (CO2) from atmospheric air, the system comprising: at least one gas-liquid contactor operable to absorb at least a portion of the CO2 from the atmospheric air into a carbonate process solution; at least one carbonate-growth reactor in fluid communication with the at least one gasliquid contactor, the at least one carbonate-growth reactor operable to react the carbonate process solution with calcium hydroxide to grow solid calcium carbonate (CaCCh); a calciner in communication with the at least one carbonate-growth reactor, the calciner comprising an interior volume in communication with at least one inlet and at least one outlet, the at least one inlet comprising a solids inlet configured to receive the solid CaCCh from the at least one carbonate-growth reactor to form a bed of the solid CaCOi in the interior volume and a fluidization gas inlet configured to receive a fluidization gas stream to fluidize the bed of the solid CaCO in the interior volume, and the at least one outlet comprising a solids outlet configured to convey a solid oxide material from the interior volume and an exhaust gas outlet configured to convey an exhaust gas stream from the interior volume; a piping network comprising: a fluidization pipeline configured to flow the fluidization gas stream to the fluidization gas inlet; and at least one heat transfer pipeline; and a heating system comprising: at least one electric heater thermally coupled to the at least one heat transfer pipeline and operable to heat a circulating gas stream; and at least one heat exchanger thermally coupled to the at least one electric heater through the at least one heat transfer pipeline and to the fluidization pipeline, the at least one heat exchanger operable to transfer heat from the circulating gas stream to the fluidization gas stream to heat the fluidization gas stream to a calcination temperature for the solid CaCCh.

31. The system of claim 30, wherein: the piping network further comprises at least one preheater pipeline; and the system further comprising a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline.

32. The system of either one of claim 30 or 31, further comprising a blower in fluid communication with the fluidization gas inlet through the fluidization pipeline.

33. The system of any one of claims 30 to 32, wherein the fluidization gas stream comprises a CO2 gas stream.

34. The system of claim 30, wherein the piping network comprises a recycle pipeline in fluid communication with the exhaust gas outlet and with the fluidization pipeline.

35. The system of claim 34, wherein: the piping network comprises at least one preheater pipeline and a condenser pipeline; and the system further comprises: a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline; and a water knock-out unit fluidly coupled to the pre-heater heat exchanger through the condenser pipeline and configured to receive a cooled exhaust gas stream from the pre-heater heat exchanger, the water knock-out unit fluidly coupled to the recycle pipeline and to the fluidization gas inlet, the water knock-out unit operable to condense water vapor from the cooled exhaust gas stream.

36. The system of claim 34, wherein: the piping network comprises at least one preheater pipeline; and the system further comprises: a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline, the pre-heater heat exchanger configured to cool the exhaust gas stream and form a cooled exhaust gas stream and heated solid carbonate material; and the recycle pipeline in fluid communication with the pre-heater heat exchanger to flow at least part of the cooled exhaust gas stream to the fluidization gas inlet.

37. The system of claim 34, wherein: the piping network comprises at least one preheater pipeline and a condenser pipeline; and the system further comprises: a pre-heater heat exchanger thermally coupled to the solids inlet through the at least one preheater pipeline and thermally coupled to the exhaust gas outlet through the at least one preheater pipeline, the pre-heater heat exchanger configured to cool the exhaust gas stream and form a cooled exhaust gas stream and heated solid carbonate material; a water knock-out unit fluidly coupled to the pre-heater heat exchanger through the condenser pipeline and configured to receive the cooled exhaust gas stream from the pre-heater heat exchanger, the water knock-out unit operable to condense water vapor from the cooled exhaust gas stream to form a dry exhaust gas stream; and the water knock-out unit fluidly coupled to the recycle pipeline and to the fluidization gas inlet to flow the dry exhaust gas stream to the fluidization gas stream.

38. The system of any one of claims 30 to 37, wherein: the piping network comprises a solid discharge pipeline that extends from the solids outlet; the at least one inlet comprises a steam inlet; and the system further comprises a steam heat exchanger thermally coupled to the solid discharge pipeline and to a source of water, and fluidly coupled to the steam inlet, the steam heat exchanger operable to transfer heat from the solid oxide material to water to generate steam for the steam inlet.

39. The system of any one of claims 30 to 37, wherein: the piping network comprises a solid discharge pipeline that extends from the solids outlet; and the system further comprises a steam heat exchanger thermally coupled to the solid discharge pipeline and to a source of water, and fluidly coupled to the fluidization pipeline, the steam heat exchanger operable to transfer heat from the solid oxide material to water to generate steam for the fluidization pipeline.

40. The system of any one of claims 30 to 39, wherein: the piping network comprises a solid discharge pipeline that extends from the solids outlet; and the system further comprises a solids cooler thermally coupled to the solid discharge pipeline and to the fluidization pipeline, the solids cooler positioned upstream of the at least one heat exchanger and operable to transfer heat from the solid oxide material to the fluidization gas.

41. The system of any one of claims 30 to 40, wherein the circulating gas stream comprises nitrogen.

42. The system of any one of claims 30 to 41, wherein the solid carbonate material is solid calcium carbonate (CaCCh).

43. The system of any one of claims 30 to 42, wherein the at least one electric heater comprises a plurality of electric heaters and the at least one heat exchanger comprises a plurality of heat exchangers, each electric heater of the plurality of electric heaters arranged with a heat exchanger of the plurality of heat exchangers to form a parallel arrangement of electric heaters and heat exchangers.

44. The system of any one of claims 30 to 42, wherein the at least one electric heater comprises a plurality of electric heaters and the at least one heat exchanger comprises a plurality of heat exchangers, each electric heater of the plurality of electric heaters arranged with a heat exchanger of the plurality of heat exchangers to form a series arrangement of electric heaters and heat exchangers, the series arrangement of electric heaters and heat exchangers operable to collectively heat the fluidization gas stream to the calcination temperature.

45. A calciner comprising: a reactor vessel comprising an interior volume and configured to calcine a solid carbonate material, the interior volume in communication with at least one inlet and with at least one outlet, the at least one inlet comprising a solids inlet configured to provide the solid carbonate material to the interior volume to form a bed of the solid carbonate material and a fluidization gas inlet configured to provide a fluidization gas stream to fluidize the bed of the solid carbonate material, the at least one outlet comprising a solids outlet configured to convey a solid oxide material from the interior volume and an exhaust gas outlet configured to convey an exhaust gas stream from the interior volume; and a heating system comprising: an electric heater operable to heat a circulating gas stream; and a heat exchanger thermally coupled to the electric heater and configured to transfer heat from the circulating gas stream to the fluidization gas stream to heat the fluidization gas stream to a calcination temperature for the solid carbonate material.