Apparatus and process for calcining feed materials

Abstract

The process for calcining a feed material can include passing the solid particulate material through or adjacent to a burner to facilitate calcination of the material. The material can be discharged from the burner flame within the calciner to travel through the body of the calciner to an outlet for further calcination of the material, such that the material has a preselected residence time as it travels through the flame and the calciner to the outlet. In some embodiments, the residence time can be 20 to 30 seconds, 1 to 3 minutes, or less than 5 minutes. Some embodiments can facilitate calcining CaCO3 material such that the calcined solid material output from the calciner consists of Ca(OH)2 (e.g., mostly Ca(OH)2, greater than 90 weight percent Ca(OH)2, etc.).

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Non-Provisional Application No. 18 / 079,203, filed December 12, 2022, which is incorporated herein by reference in its entirety.

[0002] The innovation relates to processes for calcining feedstock, apparatus for calcining feedstock (e.g., kilns, calcination burners, calcination systems, etc.), operating aspects of the apparatus, and methods of making and using them. [Background technology]

[0003] Kilns can be used to calcinate raw materials. Often, kilns are constructed as long pipes or cylinders configured to facilitate heating of calcium carbonate (CaCO) material to form calcium oxide (CaO), which may also be called lime or quicklime. Kiln operation often results in the emission of carbon dioxide (CO). Kilns are often designed to provide a long residence time to form CaO. Water can then be exposed to the CaO to form hydrated lime or hydrated lime (Ca(OH)) in a separate operational step downstream of the kiln. Summary of the Invention

[0004] It has been found that there is a need to provide improved calciner operation that may allow for shorter residence times for calcination, which may also result in significant improvements in operating efficiency and capture of carbon dioxide from the exhaust gases (or flue gases) output from the calcination process. It has also been found that it would be advantageous to provide a calciner apparatus and process that is operable to form hydrated lime (Ca(OH)) from a feed material that includes CaC0, such that the additional process step involving the hydration of lime (CaO) may be avoided. The hydrated lime formed can be partial formation of hydrated lime (e.g., calcination of the feed material occurs such that more than 5% of the feed material is calcined to hydrated lime, more than 1% of the feed material is calcined to hydrated lime, and less than 100% of the feed material is calcined to hydrated lime), substantial formation of hydrated lime (e.g., more than 70% of the feed material is calcined to hydrated lime, more than 60% of the feed material is calcined to hydrated lime, etc.), or substantially complete formation of hydrated lime (e.g., more than 90% of the feed is calcined to hydrated lime).

[0005] Embodiments of the process we have developed for calcining feedstock can include passing a solid particulate material including CaCO through a flame formed by a burner or moving adjacent to the burner (e.g., near a flame emitted from the burner via a lance) to facilitate calcination of the material. The material can be discharged from the burner flame within the calciner to move through the body of the calciner to an outlet for further calcination of the material, so that the material has a preselected residence time as it moves through the flame and the calciner to an outlet and / or an inlet to a filtration device. In some embodiments, the residence time can be 20 to 30 seconds, 1 to 2 minutes, or less than 3 minutes. Embodiments can facilitate calcination of CaCO material such that the output material from the calciner consists of Ca(OH) (e.g., predominantly Ca(OH), greater than 50 weight percent (wt%) Ca(OH), greater than 90 wt% Ca(OH), etc.), while providing an output exhaust having a high amount and / or concentration of carbon dioxide (CO) to facilitate CO capture. In embodiments in which the oxidant consists primarily of oxygen, substantially less nitrogen (N) can be used in embodiments (e.g., embodiments configured to use oxy-fuel systems, high oxygen concentration oxidizers, etc.), thereby resulting in increased CO concentrations and / or higher amounts of CO.

[0006] Embodiments may utilize one or more filtration mechanisms for filtering solid particles comprising calcined material (e.g., material that is primarily Ca(OH) or CaO, etc.) from the exhaust gas before the exhaust gas passes through the carbon capture system. Other embodiments may not need to utilize a filtration mechanism. For example, some embodiments may be incorporated into an electric arc furnace arrangement or cement manufacturing facility such that the calcined material can be output to a rotary kiln for cement production without filtration, or can be fed to a slag for slag processing without the need for filtration.

[0007] Embodiments may be configured for use with dry or wet feed materials. In embodiments that may utilize wet feed materials, the feed material may be passed through at least one dryer to dry the feed material before it is fed into the kiln and / or injected into the flame formed in the kiln.

[0008] Embodiments may utilize a burner to form a flame within the calciner, which can provide a high calcination temperature to the material fed through the flame. An oxidizer having an oxygen content of 21 volume percent (vol%) to 100 volume% may be utilized by the burner to form the flame within the calciner. For example, the oxygen content of the oxidizer utilized by the burner may be within the range of 21 volume% to 100 volume%, 30 volume% to 70 volume%, 35 volume% to 60 volume%, or other suitable range of oxygen content (e.g., 95 volume% oxygen to 100 volume% oxygen, 90 volume% oxygen to 100 volume% oxygen, 95 volume% oxygen to 99.99 volume% oxygen, etc.). The oxidizer may be any suitable oxidizer. For example, the oxidizer may include, for example, air, oxygen-enriched air, and / or an oxygen gas stream.

[0009] The burner may utilize a fuel for combustion to form a flame, which may include natural gas, diesel, pulverized coal, hydrogen, or other suitable fuel source.

[0010] The filtration mechanism, if utilized, may include one or more cyclones and / or one or more baghouse filters. The filtration mechanism may also, or alternatively, include other filtration mechanisms suitable for removing solid particulate calcined material output from the kiln from the hot exhaust gas output from the kiln prior to undergoing carbon capture.

[0011] It has been found that embodiments of the apparatus and process of the present invention can allow low residence time calcinations to occur. This can allow for a substantial reduction in calcination system sizing, as the size and length of the calciner and associated equipment can be substantially reduced due to the significantly lower residence times. Such a feature can provide significant capital cost savings, as well as reduced operating and maintenance costs.

[0012] Furthermore, it has been found that embodiments can be adapted to provide more efficient calcination, which can provide for calcining feed materials containing CaCO (e.g., limestone materials) into solid particles containing primarily Ca(OH). This type of calcination operation can avoid the need to hydrate lime (CaO) to form such materials by exposing the CaO to water in a separate operation step. This type of operation can provide substantial operational flexibility and further improved operational performance, resulting in significant improvements in operational efficiency.

[0013] It has been found that embodiments can also provide higher concentrations of CO or higher relative flow rates of CO in the exhaust gas output from the calciner, which can provide improved carbon capture for the capture of CO (e.g., as a product gas from an operation). The improvements can include improved higher concentrations of captured CO (e.g., higher CO capture rates) and / or higher concentrations of CO in the gas output from the calciner with the calcined material. This can provide further improvements in operational efficiency for embodiments adapted to provide CO as a product from an operation, such as, for example, calcining a material.

[0014] In a first aspect, a process for calcining a feed material is provided that can include feeding a solid particulate material to a flame formed in a calciner such that the solid particulate material passes through the flame as it moves through the calciner to an outlet of the calciner.

[0015] In a second embodiment, the solid particulate material may have a residence time for firing of 5 minutes to 5 seconds, 3 minutes to 5 seconds, 10 seconds to 30 seconds, or 5 seconds to 1 minute.

[0016] In a third aspect, feeding the solid particulate material to the flame can include moving the solid particulate material into a burner for feeding into the calciner via the burner and / or moving the solid particulate material into a calciner adjacent to the flame so that the solid particulate material passes through the flame. In some embodiments, all of the solid particulate material can be fed into the burner for feeding into the calciner via the burner, such that the particulate material is fed into the flame via the burner. Other embodiments can be configured such that all of the solid particulate material can be fed into the calciner adjacent to the flame so that the solid particulate material passes through the flame (e.g., via at least one lance feed, etc.). In still other embodiments, some of the solid particulate material can be fed into the burner for feeding into the calciner via the burner, such that the particulate material is fed into the flame via the burner, and other solid particulate material can be fed into the calciner adjacent to the flame so that the solid particulate material passes through the flame (e.g., via at least one lance feed, etc.).

[0017] In a fourth aspect, the process can also include supplying a fuel and at least one oxidant stream to a burner for forming a flame in the kiln.

[0018] In a fifth aspect, the flame formed within the calciner via the at least one burner can be configured to facilitate calcination of the solid particulate material at a preselected calcination temperature range of 815°C to 2,205°C, 815°C to 1,370°C, 815°C to 1,650°C, 925°C to 1,650°C, or 925°C to 1,370°C.

[0019] In a sixth aspect, the calcined material can include 70 weight percent (wt%) Ca(OH)2 to 100 wt% Ca(OH)2, 80 wt% Ca(OH)2 to 100 wt% Ca(OH)2, or 90 wt% Ca(OH)2 to 100 wt% Ca(OH)2, or can include a calciner output concentration of CaO and Ca(OH)2. In yet other embodiments, the calcined material can include greater than 50 wt% Mg(OH)2, greater than 75 wt% Mg(OH)2, greater than 90 wt% Mg(OH)2, or greater than 95 wt% Mg(OH)2, or 90 wt% Mg(OH)2 to 100 wt% Mg(OH)2 (e.g., 95 wt% Mg(OH)2 to 98 wt% Mg(OH)2). In yet other embodiments, the calcined material can include a kiln output concentration of the calcined material that includes a concentration of MgO and Mg(OH). For example, in some embodiments, the calcined material can include a kiln output concentration of the calcined material that includes greater than 20 wt.% Mg(OH) and greater than 50 wt.% Ca(OH), a concentration of 5 wt.% Mg(OH) to 30 wt.% Mg(OH), and a concentration of 70 wt.% Ca(OH) to 95 wt.% Ca(OH), or another suitable composition having a kiln output concentration of Mg(OH) and Ca(OH), or a kiln output concentration of MgO, CaO, Mg(OH), and Ca(OH).

[0020] In a seventh aspect, the feed material can consist of at least 70 weight percent carbonate material and no more than 30 weight percent impurities. Other embodiments can utilize other types of feed compositions.

[0021] In an eighth aspect, the feed material can have an average particle size of 50 micrometers to 2,000 micrometers, and / or a maximum particle size of 5,000 micrometers or less. In some embodiments, the feed material can also (or alternatively) have a minimum particle size of 5 micrometers or less.

[0022] In a ninth aspect, the process can also include filtering the flow output from the outlet of the calciner to separate the solid particulate material from the combustion gases formed from the formation of the flame. The solid particulate material can be separated from the combustion gases that are the calcined material.

[0023] In a tenth aspect, the process can include passing the solid particulate material through at least one dryer before feeding the solid particulate material to a flame in a calciner, and transferring the combustion gases to the dryer to dry the solid particulate material in the dryer before transferring the combustion gases to a carbon capture system to capture carbon dioxide from the combustion gases.

[0024] In an eleventh aspect, the process may include filtering the stream output from the calciner outlet to separate the solid particulate material from combustion gases formed from the formation of a flame. The solid particulate material separated from the combustion gases may be calcined material. The process may also include cooling the stream output from the calciner outlet prior to filtering. In some embodiments, the cooling medium for cooling the stream output from the calciner outlet prior to filtering may include carbon dioxide.

[0025] In a twelfth aspect, the first aspect of the process can be combined with any and / or all of aspects two through eleven to form further aspects. For example, the first aspect can be combined with the second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, and / or eleventh aspects to form further embodiments of the process.

[0026] In a thirteenth aspect, an apparatus for calcining a feed material is provided. Apparatus embodiments can be configured to implement process embodiments for calcining a feed material. The apparatus can include a calciner and at least one burner positioned adjacent to an inlet portion of the calciner such that solid feed material fed into the calciner can pass through the burner and at least one flame formed in the calciner for calcining the solid feed material. The calciner and the at least one burner can be arranged and positioned such that the solid feed material can pass through the at least one flame to an outlet of the calciner for calcining the solid feed material.

[0027] In a fourteenth aspect, the apparatus may also include at least one filtration device connectable to the outlet of the calciner to receive the solid feed material and combustion gases from the outlet of the calciner and to filter solid particles of the solid feed material from the combustion gases.

[0028] In a fifteenth aspect, the apparatus may be configured such that at least one burner and calciner are positioned and configured to have a residence time for calcination of the solid feed material of 5 minutes to 5 seconds, 3 minutes to 5 seconds, 10 seconds to 30 seconds, or 5 seconds to 1 minute.

[0029] In a sixteenth aspect, the apparatus may be constructed and arranged such that at least one burner is connectable to a source of fuel, at least one source of oxidant, and at least one source of solid feed material, such that at least a portion of the solid feed material can be supplied to the burner for feeding into the flame.

[0030] In a seventeenth aspect, the apparatus may be configured such that the calciner is connectable to a source of at least one solid feed material such that at least a portion of the solid feed material can be fed to the calciner for movement into the flame for partial calcination in the flame in a first stage of calcination before moving out of the flame toward an outlet of the calciner for further calcination in a second stage of calcination.

[0031] In an eighteenth aspect, the at least one burner and the calciner may be arranged and configured such that the flame facilitates calcination of the solid feed material at a preselected calcination temperature range of 815°C to 2,205°C, 815°C to 1,370°C, 815°C to 1,650°C, 925°C to 1,650°C, or 925°C to 1,370°C.

[0032] In a nineteenth aspect, the apparatus can include a carbon capture system positioned downstream of the kiln outlet for capturing carbon dioxide from the combustion gases output from the kiln outlet.

[0033] In a twentieth aspect, the first aspect of the process may include utilization of any of the apparatus aspects discussed herein, along with any other of the second through twelfth aspects of the process described above.

[0034] In a twenty-first aspect, the device of the thirteenth aspect may include any combination of the fourteenth to nineteenth aspects to form another aspect. For example, the thirteenth aspect may be combined with all of the fourteenth, fifteenth, sixteenth, seventeenth, eighteenth, and nineteenth aspects. As yet another example, the thirteenth aspect may be combined with two or more of the fourteenth, fifteenth, sixteenth, seventeenth, eighteenth, and nineteenth aspects.

[0035] In a twenty-second aspect, a calcination system is provided. The calcination system may be an embodiment of an apparatus. For example, the system may include a calcination furnace having an outlet communicating with the chamber, at least one burner connected to the calcination furnace to form at least one flame within the chamber for calcination at a preselected calcination temperature range of 815°C to 2,205°C, and at least one filtration device connected to the outlet of the calcination furnace to receive the calcined material entrained in the combustion gas from the calcination furnace for separating the calcined material from the combustion gas. The system may also include a carbon capture system connected to the at least one filtration device to receive the combustion gas for removing moisture from the combustion gas and capturing carbon dioxide from the combustion gas. A source of solid particulate feed material may be connectable to the at least one burner and / or the calcination furnace to supply the solid particulate feed material into the at least one flame for a first stage of calcination of the solid particulate feed material. The calciner may also be sized and configured to move the solid particulate feed material from the flame to an outlet within the calciner chamber for a second stage of calcination of the feed material such that a preselected residence time of the solid particulate feed material for calcination to form a calcined material is greater than 5 seconds and less than or equal to 5 minutes.

[0036] The process embodiments discussed herein may be implemented via the system embodiments, which may also utilize other elements (e.g., automatic process control elements, sensors, conduits, compressors, heat exchangers, etc.).

[0037] Other details, objects, and advantages of the process for calcining feedstock, the apparatus for calcining feedstock (e.g., calcination furnaces, calcination burners, calcination systems, etc.), the operating aspects of the apparatus, and methods of making and using the same will become apparent as the following description of certain exemplary embodiments thereof proceeds. [Brief explanation of the drawings]

[0038] Exemplary embodiments of processes for calcining feedstock, apparatus for calcining feedstock (e.g., calcination furnaces, calcination burners, calcination systems, etc.), operational aspects of the apparatus, and methods of making and using the same are shown in the drawings included herein. It should be understood that like reference numerals used in the drawings may identify like components. [Figure 1] 1 is a schematic block diagram of a first exemplary embodiment of an apparatus for calcining a feed material that may utilize an exemplary embodiment of a process for calcining a feed material; [Figure 2] 1 is a schematic cross-sectional view of a first exemplary embodiment of a burner 3. FIG. [Figure 3] 3 is a schematic end view of a first exemplary embodiment of the burner 3 shown in FIG. 2. FIG. [Figure 4] 2 is another schematic cross-sectional view of another exemplary embodiment of the burner 3. FIG. [Figure 5] FIG. 5 is a schematic end view of an exemplary embodiment of the burner 3 shown in FIG. 4. [Figure 6] 1 is a scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM / EDS) image of a first sample obtained from testing of an exemplary embodiment of an exemplary apparatus for calcining a feedstock. The first sample is a raw sample before undergoing any calcination. The first sample may also be referred to as Sample 1. [Figure 7] 1 is an SEM / EDS image of a second sample obtained from testing of an exemplary embodiment of an exemplary apparatus for calcining a feedstock. The second sample is a partially calcined sample extracted while the sample was exposed to flame 3F emitted by burner 3 of calcination furnace 11. The second sample may also be referred to as sample 2. [Figure 8] 1 is an SEM / EDS image of a third sample obtained from testing of an exemplary embodiment of an exemplary apparatus for calcining a feed material. The third sample is a calcined sample obtained after the material passed through a calciner with a residence time of 30 seconds. The third sample may also be referred to as Sample 3. [Figure 9]1 is a series of graphs showing data obtained via X-ray powder diffraction (XRD), illustrating the diffraction peaks in the XRD data compared to a reference pattern for Sample 1, which was the raw material sample before being calcined in the experiments conducted herein. [Figure 10] 1 is a series of graphs illustrating data obtained via XRD, illustrating the diffraction peaks in the XRD data matched to a reference pattern for Sample 2, which was a sample of partially calcined material taken from within Flame 3F during the first stage F1 of calcination in the experiments conducted herein. [Figure 11] 1 is a series of graphs illustrating data obtained via XRD, illustrating the diffraction peaks in the XRD data compared to a reference pattern for Sample 3, which was the sample of calcined material output from the outlet of calciner 11 after being discharged from the outlet of the calciner after the second stage F2 of calcination in the experiments conducted herein. [Figure 12] 1 is a series of graphs illustrating fits of calculated intensities from a refined sample model of Sample 1 to observed XRD data for Sample 1 obtained during the experiments discussed herein. [Figure 13] 1 is a series of graphs illustrating fits of calculated intensities from a refined sample model of Sample 2 to observed XRD data for Sample 2 obtained during the experiments discussed herein. [Figure 14] 10 is a series of graphs illustrating fits of calculated intensities from a refined sample model of Sample 3 to observed XRD data for Sample 3 obtained during the experiments discussed herein. DETAILED DESCRIPTION OF THE INVENTION

[0039] 1-5, an apparatus 1 for calcining a feed material can include at least one burner 3 connected to an inlet end or portion of a calciner 11. The calciner 11 can be a tube, pipe, or other type of calciner structure (e.g., rectangular cross-sectional shape, hexagonal cross-sectional shape, cubic cross-sectional shape, rectangular cross-sectional shape, cylindrical cross-sectional shape, etc.). In some embodiments, the inlet of the calciner 11 can be higher than the outlet of the calciner, such that the calciner 11 is a downslope calciner or is in an inclined orientation, so that gravity helps to facilitate the flow of particulate material 11F entrained in gas (e.g., flue gas from fuel combustion) through the body of the calciner from its inlet region to its outlet. The calciner 11 can, in some embodiments, be refractory-lined.

[0040] There may be a single burner 3 or multiple burners 3 for forming at least one flame 3F in the chamber of the kiln 11. Each burner 3 may receive fuel from a fuel source 5 for forming the flame 3F. A fuel supply conduit 6 may connect a fuel source to the burner 3 to supply fuel to the burner 3. The fuel 3 may be a combustible fuel, such as natural gas, hydrogen, ammonia, diesel, or pulverized coal. An oxidant source 7 may connect to the burner 3 to also supply at least one oxidant stream to the burner 3. The oxidant may be air, oxygen-enriched air, oxygen, or another type of oxidant stream. The oxidant stream may include oxygen at a concentration of 21 volume percent (vol%) oxygen to 100 volume% oxygen. In some embodiments, the oxygen concentration in the oxidizer can be 85% by volume or greater (e.g., at least 90% by volume oxygen, 90% by volume to 100% by volume oxygen, 95% by volume to 100% by volume oxygen, 95% by volume to 99.99% by volume oxygen, 85% by volume to 99.99% by volume oxygen, etc.).

[0041] In some embodiments, there may be a first oxidant source 7 and a second oxidant source 7a (shown in dashed lines) for supplying different streams of oxidant to burner 3. In embodiments in which multiple streams of oxidant may be utilized as the oxidant supply to burner 3, there may be a first oxidant supply conduit between the first oxidant source and the burner and a second oxidant supply conduit between burner 3 and the second oxidant source. The oxidant for each stream of oxidant may be air, oxygen-enriched air, oxygen, or another type of oxidant stream. In some embodiments, the different streams of oxidant may be different types of oxidant (e.g., a stream of air and a stream of oxygen-enriched air may be first and second oxidant streams supplied to burner 3, a stream of oxygen and a stream of oxygen-enriched air may be first and second oxidant streams supplied to burner 3, etc.). The oxidant streams supplied to burner 3 from each oxidant source may contain oxygen at a concentration of 21 volume percent (vol%) oxygen to 100 volume% oxygen.

[0042] In other embodiments, there may be only a single stream of oxidant supplied to the burner 3 via an oxidant supply conduit 4 (which may also be considered a first oxidant supply conduit) positioned between the oxidant source 7 and the burner 3. In such embodiments, the oxidant may be air, oxygen-enriched air, or oxygen supplied to the burner via at least one compressor or other oxidant source.

[0043] Solid particulate feed material may be supplied to the calciner 11 and / or burners 3 via a feed supply conduit 8, which may be positioned between a source 9 of feed material and the burners 3 and / or calciner 11. In some embodiments, the feed supply conduit 8 may supply the solid particulate material to the oxidant stream for mixing at a mixing location 4a upstream of the burners 3. For example, there may be an in-line mixer or other type of mixer device positioned at the mixing location 4a to facilitate mixing of the solid particles of the feed material with the oxidant stream passing through the oxidant supply conduit 4. The mixture of solid particles of the feed material entrained in the oxidant may travel from the mixing location 4a to the burners 3 for exiting the burners 3 and being discharged into the flame 3F formed by the burners 3.

[0044] Additionally or alternatively, feed material may be supplied to the burner 3 from a feed material source 9 via a separate feed material supply conduit 10. In such embodiments, the feed material may be entrained in a carrier gas (e.g., an oxidant or other suitable carrier gas, such as carbon dioxide gas or flue gas) before being supplied to the burner 3, or may be supplied to the calciner 11 or the burner 3 without being entrained in a fluid or gas. In some embodiments, the particulate feed material may also, or alternatively, be supplied into the calciner 11 adjacent to the burner 3 and into the flame 3F generated by the burner 3, such that the particulate material is supplied into the flame 3F for calcination within the flame 3F for the first stage F1 of calcination before exiting the outlet of the calciner 11 and moving along the flow path of the particulate material flow 11F toward the outlet of the calciner 11 for further calcination within the calciner 3 during the second stage F2 of calcination. For example, at least some of the particulate feed material may be fed via lance feed conduit 10L to a lance adjacent the burner for delivery into the kiln 11 adjacent the burner 3 and flame 3F.

[0045] It should be understood that the particulate feed material may be fed completely through the burner 3, partially through the burner 3 and also partially adjacent to the burner 3, or completely into the calciner 11 adjacent to the burner 3 and flame 3F (e.g., via a lance feed conduit 10L, etc.). In such embodiments, the particulate feed material may be entrained in a carrier gas, which may be air, oxygen-enriched air, carbon dioxide, flue gas, etc., to facilitate feeding of the solid particulate feed material into the burner 3 and / or calciner 11.

[0046] Feed material fed into the calciner 11 (directly and / or via burners 3) can remain in the calciner for a preselected residence time. This residence time can include the time calcined via exposure to and calcination within the flame 3F during the first stage of calcination F1, and the time the material exits the flame 3F, travels to the outlet of the calciner 11, and undergoes further calcination in the second stage of calcination F2, which can occur while the temperature is at or within the preselected calcination temperature range of the calciner 11. The residence time of the particulate material within the calciner 11 can be a preselected residence time that is, in some embodiments, less than 30 seconds, 20-30 seconds, less than 1 minute, less than 2 minutes, less than 3 minutes, or between 10 seconds and 3 minutes. Other embodiments can be configured to utilize other suitable residence times (e.g., less than 5 minutes and more than 3 seconds, 10 seconds to 5 minutes, less than 7 minutes and more than 1 second, etc.). The preselected residence time can be selected to provide a preselected conversion rate of the calcination of the feed material. For example, the preselected conversion rate can be 95% to 100% conversion of the carbonate material, 90% to 100% conversion of the carbonate material, or a conversion rate that is at least 95% of the carbonate material. Other suitable conversion rates can also be selected for the preselected conversion rate, upon which the preselected residence time can be based.

[0047] The preselected firing temperature range for the calciner 11 can be above 815° C., up to 2205° C., above 1090° C., or in the range of 1370° C. to 1650° C., or up to 2205° C. In some embodiments, the preselected temperature range can include a flame temperature of flame 3F in the range of 1370° C. to 1650° C., in the range of 925° C. to 1650° C., or in the range of 925° C. to 2205° C., and a temperature in the calciner 11 downstream of the flame that is below 1650° C. and above 815° C., or below 2205° C. and above 815° C. In some embodiments, the preselected temperature range of the calciner 11 can include a first temperature range for the first stage F1, which can be in the range of 1,370°C to 1,650°C, the range of 1,090°C to 1,650°C, the range of 925°C to 1,650°C, or the range of 925°C to 2,205°C, and a second temperature range for the second stage F2, which is less than 1,650°C and greater than 815°C, less than 925°C and greater than 815°C, or less than 2,205°C and greater than 815°C.

[0048] At least one filtering device 12 may be positioned downstream of the calciner 11 to receive a flow of particulate material entrained in combustion gases (e.g., flue gases) output from the calciner 11. The filtering device 12 may include an inlet 12a region. The preselected residence time may include the time the particulate material is held in this inlet region before undergoing filtration through the at least one filtering device 12 (referred to as "filter" in FIG. 1). This portion of the residence time may be, for example, part of the second stage F2 of the calcination.

[0049] The at least one filtering device 12 may include one or more cyclones, one or more bag houses, one or more high-temperature particulate separators, one or more dust filters, combinations thereof, or other configurations of filtering mechanisms for separating the calcined particulate material output from the outlet of the calciner 11 from the high-temperature exhaust gases of the particulate material stream 11F entrained in the exhaust gases formed via combustion of fuel via the burner 3. A filtering feed conduit 12a may be connected between the outlet of the calciner 11 and the filtering device 12 for supplying the calcined solid particulate feed material entrained in the combustion gases output from the outlet of the calciner 11 to the at least one filtering device 12.

[0050] In some configurations, a calcined particle cooling device 12b may also be positioned between the outlet of the calciner 11 and the at least one filtering device 12 to cool the stream output from the calciner outlet to a preselected filtering temperature range prior to filtering the calcined solid particulate material from the combustion gases output from the calciner outlet. Such a cooling system may utilize a recycled stream of carbon dioxide output from the carbon capture system 20 to provide the cooling medium for the cooling system. Alternatively, air or other fluid may be used as the cooling medium for the cooling device 12b.

[0051] The solid calcined particulate material separated from the exhaust gas stream may be output from the at least one filtration device 12 via a product output conduit 13 to provide a product material, which may include the calcined particulate material output from the calciner 11. The at least one filtration device 12 may also output at least one stream of filtered gas 14, which may be fed to a carbon capture system 20, which may be configured to capture carbon dioxide (CO). The carbon capture system 20 may be configured to capture CO as a product stream to provide a CO product (e.g., compressed liquid CO, compressed gaseous CO, other CO products, etc.).

[0052] For example, at least one stream of filtered gas 14 may be supplied to a carbon capture system 20 for removing moisture or other undesirable components from combustion gases separated from the calcined material output from the outlet of the calciner 11 to form high-purity carbon dioxide or otherwise capture carbon dioxide. For example, the carbon capture system 20 may be configured to condense water and other non-CO2 components from the combustion gas stream (e.g., carbon monoxide (CO) in addition to water) or may include scrubbing, compression, and drying elements for impurity removal to capture CO2. The purified exhaust gas (e.g., combustion gas) output from the calciner 11 may be supplied to a CO2 capture device 23 of the CO2 capture system 20 for CO2 sequestration for storage and / or distribution. In some embodiments, a vent stream 25 may be output from the CO2 capture device 23 for release to the atmosphere or for supply to another plant process for other uses (e.g., as a heating medium in a heat exchanger).

[0053] In some configurations, embodiments may not utilize an optional filtering device 12. For example, embodiments may be incorporated into a cement manufacturing plant such that a feed material 9 containing solid particulate material is fed directly into a rotary kiln of the cement manufacturing plant to pass through a flame 3F for the formation of lime. In such embodiments, a filtering device 12 may not be necessary or used, as the formed calcined material can be used directly in the kiln without filtration. Combustion gases from the burner 3 may be output from the rotary kiln for treatment prior to the release of any process gases from the cement manufacturing facility. In such embodiments, the rotary kiln of the cement manufacturing plant having a burner 3 for forming a flame 3F therein may be considered a calciner 11. Alternatively, such embodiments may be configured such that a filtering device 12 for filtering the calcined solid particulate material from the combustion gases is not necessary or used, and the calcined material can be fed to the rotary kiln of the cement manufacturing plant.

[0054] As another example of an embodiment that may not or does not use a filtration device 12 for filtering the calcined solid particulate material output from the calciner 11, an embodiment may be provided in an electric arc furnace used for slag formation to produce steel. In such an embodiment, solid particulate feed material may be fed into a flame 3F formed in the calciner 11 to produce calcined material that can be fed to a slag for use in forming slag via the arc furnace. In such an embodiment, filtration of the solid particulate material may not be necessary because the calcined material can be fed to a slag for use in slag formation without the need for filtration. Exhaust gas from the operation may be output for carbon capture or other types of processing before release of any unused or uncaptured exhaust gas components. The slag formed in such an embodiment may then be utilized to form a steel body (e.g., an ingot containing steel formed from the slag).

[0055] In some configurations, the feed material from the feed material source 9 may be wet (e.g., considered mud or contain moisture). For example, the feed material may include limestone mud / dust containing a water concentration ranging from 20 weight percent (wt%) water to 40 wt% water, 10 wt% water to 40 wt% water, or other water concentrations. The feed material in such embodiments may undergo a pre-drying process by passing through at least one dryer 15 (shown in dashed lines) before being supplied to the burner 3 and / or the calciner 11. The dryer 15 may be positioned between the at least one filtration device 12 and the CO2 capture system 20 to utilize a hot exhaust stream of gas 14 output from the calciner 11 to provide hot gas that can facilitate drying of the feed material via a heat exchanger arrangement with the feed material in the dryer 15. In such embodiments, such hot exhaust stream of gas 14 may be output from the calciner 11 and then filtered by the at least one filtration device 12 before being supplied from the filtration device 12 to the dryer 15. After passing through the dryer 15, the exhaust gas stream may be output from the dryer 15 to be fed to a CO2 capture system 20 (eg, fed to a condenser 21, etc.).

[0056] As noted above, at least one filtration device 12 (if utilized) may include one or more cyclones, one or more baghouse filters, one or more solid particle separators, and / or combinations thereof to facilitate filtration of solid particles from the flue gas output from the outlet of the calciner 11 or the stream 11F of particulate material entrained in the combustion gas. For these types of configurations of the apparatus 1 that may also utilize a dryer 15, the filtration supply conduit 12a may be positioned between the filtration device 12 and the outlet of the calciner 11. The filtration supply conduit 12a may include, for example, a hopper or inlet of a particle supply vessel of the filtration apparatus (e.g., a cyclone hopper, a cyclone or baghouse inlet, etc.) connected to the outlet of the calciner 11.

[0057] As also described above, it should be understood that embodiments of burner 3 can utilize different types of fuel or oxidizer. For example, as an alternative (or in addition) to using natural gas, embodiments can utilize atomized liquid fuel or pulverized solid fuel (e.g., pulverized coal) in a carrier gas or other fuel source. It should also be understood that the fuel can include a combustible material. Examples of fuels include natural gas, propane, hydrogen, diesel, coal, or other fuel sources that can be combusted. The fuel can travel through at least one nozzle of burner 3.

[0058] Oxidant can refer to a fluid containing a concentration of oxygen that can be utilized for the combustion of fuel. For example, the oxygen content of the oxidant utilized in burner 3 can be within the range of 21% oxygen to 100% oxygen by volume, 30% oxygen to 70% oxygen by volume, 35% oxygen to 60% oxygen by volume, or other suitable oxygen content ranges. In some configurations, the oxidant stream supplied to burner 3 can be, for example, 90% oxygen to 100% oxygen by volume. The oxidant can be any suitable oxidant. For example, the oxidant can include, for example, air, oxygen-enriched air, and / or oxygen gas streams. The oxidant can travel through a nozzle of the burner element (e.g., an annular nozzle that surrounds the inner nozzle of the burner element or is the central innermost nozzle of the burner element).

[0059] In some embodiments, fuel or other materials may be included along with the oxidizer that travels through an annular nozzle or other type of nozzle of the burner 3. In other embodiments, the fuel may pass through one or more nozzles while the feed material and / or oxidizer passes through one or more other nozzles of the burner 3.

[0060] Exemplary burners 3 that may be used in the apparatus 1 for calcining a solid feed material can be understood from the above, as can the exemplary embodiments of the burner 3 shown in Figures 2-5. For example, the burner 3 may be constructed to include a first inner nozzle 3d, a second annular nozzle 3e spaced apart from the first inner nozzle 3d and positioned around the periphery of the first inner nozzle 3d, and a third annular nozzle 3f spaced apart from the second annular nozzle 3e and positioned around the second annular nozzle 3e, such that the second annular nozzle 3e includes multiple concentric nozzles positioned between the first inner nozzle 3d and the third annular nozzle 3f. The third annular nozzle 3f may, in some embodiments, be considered the outermost nozzle. The first inner nozzle 3d may be positioned centrally and inwardly relative to the second annular nozzle 3e and the third annular nozzle 3f. The cross-sectional shape of the first inner nozzle may be any suitable shape (e.g., circular, elliptical, polygonal, etc.). The annular cross-sections of the second annular nozzle 3e and the third annular nozzle 3f may also be of any suitable cross-sectional shape, such as, for example, an annular shape.

[0061] The nozzle of the burner 3 may be positioned on a burner outlet plane of the burner 3 facing the internal cavity, chamber, or channel of the calciner 11 to combust fuel and emit a flame 3F at the calciner 11. The flame 3F may be adjacent to an inlet region of the calciner 11, for example. The inlet region may be on a first side of the calciner 11 opposite an outlet side of the calciner 11, from which the calcined material and exhaust gases may be output (e.g., toward or into the filtering device 12, as discussed above).

[0062] In some embodiments, such as those shown in FIGS. 2-3, the burner 3 may be configured to emit a first oxidant stream 3c containing a first oxidant at a first oxidant velocity. The first oxidant may be oxygen, oxygen-enriched air, or air. For example, the first oxidant may be, for example, 95% oxygen by volume, or 80% oxygen by volume to 100% oxygen by volume. The first oxidant outlet velocity may be the speed of sound or another suitable velocity (e.g., 10 m / s to 100 m / s, etc.). The velocity of the first oxidant stream 3c may also be considered the velocity of the first oxidant stream 3c output from the burner 3.

[0063] The first annular nozzle 3e can discharge the first fuel stream 3b at a first fuel velocity. The first fuel of the first fuel stream 3b can include natural gas, and the first fuel velocity can be any suitable velocity (e.g., 10 to 100 m / s, or 5 to 110 m / s, etc.). The first fuel of the first fuel stream 3b can alternatively include diesel, pulverized coal mixed with air, hydrogen, or other suitable fuel. The velocity of the first fuel stream 3b can also be considered the velocity of the first fuel stream 3b output from the burner 3.

[0064] The second annular nozzle 3f can emit a first particulate stream 3a. The first particulate stream 3a can include solid particulate material from the feedstock source 9 entrained in a carrier gas. The carrier gas of the first particulate stream 3a can be or include an oxidizer. For example, the oxidizer of the first particulate stream 3a can include an oxidizer of the same type as the first oxidizer or a different oxidizer. For example, the first particulate stream 3a can include a second oxidizer, which can be air or oxygen-enriched air, while the first oxidizer of the first oxidizer stream 3c is oxygen. As another example, the oxidizer of the first particulate stream 3a can be oxygen, and the oxidizer of the first oxidizer stream can also be or include oxygen.

[0065] Alternatively, the carrier gas entrained with the particulate feed material of first particulate stream 3a may not contain an oxidant. For example, the carrier gas may contain carbon dioxide to fire a feed material that may not have any oxygen or a low concentration of oxygen (e.g., less than 3% oxygen by volume), or may be flue gas output from a combustor connected to apparatus 1 or other element of a plant.

[0066] The velocity of the first particle stream 3a (e.g., particles entrained in a second oxidant or other carrier gas) can be any suitable velocity (e.g., a velocity of 1-65 m / sec, etc.) The velocity of the first particle stream 3a can also be considered as the velocity of the first particle stream 3a output from the burner 3.

[0067] Other embodiments of the burner 3 may be configured so that different nozzles emit different streams. For example, as shown in the embodiment of Figures 4-5, the first inner nozzle 3d of the burner may emit a first particle stream 3a, the second annular nozzle 3e may emit a first fuel stream 3b, and the third annular nozzle 3f may emit a first oxidant stream 3c.

[0068] The exemplary burner 3 of Figures 2-3 may also be configured such that the first inner nozzle 3d can emit a first particle stream 3a, the second annular nozzle 3e can emit a first fuel stream 3b, and the third annular nozzle 3f can emit a first oxidant stream 3c, such that the burner 3 of Figures 2-3 operates as follows:

[0069] Also, the exemplary burner 3 of Figures 4-5 may alternatively be configured such that the first inner nozzle 3d of the burner can emit a first oxidant stream 3c, the second annular nozzle 3e can emit a first fuel stream 3b, and the third annular nozzle 3f can emit a first particle stream 3a.

[0070] In yet other embodiments, the burners 3 of Figures 2-3 and 4-5 may be configured such that the first particle stream 3a does not include any particles and consists solely of the second oxidant. In such embodiments, particles from a feed source may be fed only into the kiln 11 adjacent to the flame 3F (e.g., via a lance feed conduit 10L) for passage through the flame 3F. In such embodiments, the first particle stream 3a may be considered a second oxidant stream, since there are no particulates entrained in that stream.

[0071] In yet other embodiments (e.g., burner configurations in which particulate material is not fed through the burner to be injected into the flame 3F), the burner 3 may not include more than two nozzles. Instead, the burner 3 may include a single nozzle having fuel entrained with oxidizer, or first and second nozzles that emit a first oxidizer stream and a first fuel stream. As yet another alternative embodiment, the burner 3 may include multiple nozzles, including a first nozzle through which fuel is output and a second nozzle through which particulate material entrained with oxidizer is output to combust the fuel and form the flame 3F within the calcination furnace 11. It should therefore be understood that numerous other burner designs may be utilized to form the flame 3F within the calcination furnace 11 so that the calcination furnace 11 operates within a preselected calcination temperature range for the first and second stages F1 and F2 of the calcination.

[0072] Burner 3 may be configured to emit flame 3F and may operate at a preselected equivalence ratio. The equivalence ratio may be the ratio of the actual fuel / oxidizer ratio to the stoichiometric fuel / oxidizer ratio. The preselected equivalence ratio may be in a range of 0.8 to 1.2, etc. In some embodiments, the preselected equivalence ratio may be, for example, 0.9 to 1.05 or greater, 0.9 to 1.1, 0.9 to 1.05, 0.95 to 1.0, 0.9, 0.95, 1.0, or 0.9 to 1.1.

[0073] An embodiment of the apparatus 1 for calcining a feedstock may include a plurality of sensors and other process control elements (e.g., control valves, etc.) communicatively connected to a controller. The controller may include a workstation implementing an automated process control program, which is also communicatively connected to the control valves, sensors, and other control elements, or may be a controller included in a distributed control system (DCS). The controller may include a computing device having a processor connected to a non-transitory computer-readable medium on which the code of the control program is stored, and at least one transceiver for communicatively connecting to the control valves and sensors (e.g., via a network connection, a wireless network connection, a wired communication connection, etc.). One or more input devices may be connectable to the controller to allow a user to provide input to the controller. One or more output devices (e.g., a display, a printer, etc.) may similarly be communicatively connected to the controller to provide output to the user.

[0074] Embodiments of the apparatus 1 for calcining a feed material may be configured so that the solid particulate feed material provided from the feed material source 9 to the burner 3 and / or calciner 11 includes a carbonate material. The carbonate material may be, for example, CaCO3, MgCO3, a combination of CaCO3 and MgCO3, or other suitable carbonate material. The material composition of the feed material may include a preselected carbonate composition and impurity concentration.

[0075] The preselected carbonate composition can include, for example, magnesium carbonate and / or calcium carbonate. For example, the preselected carbonate concentration can be at least 70 wt.% CaCO3, 70 wt.% to 99 wt.% CaCO3, or other suitable CaCO3 concentration, or 70 wt.% MgCO3, 70 wt.% to 99 wt.% MgCO3, or other suitable MgCO3. The preselected carbonate concentration can also include a combination of MgCO3 and CaCO3, comprising at least 70 wt.% or 70 wt.% to 99 wt.% of the feed material.

[0076] The impurity concentration can be up to 30% by weight impurities, 30% to 1% by weight impurities, or other suitable impurity concentrations. The impurities in the source material impurity concentration can include one or more of Fe2O3, SiO2, Al2O3, and other impurities.

[0077] In some embodiments, the feed material may be, for example, crushed limestone or other suitable feed material. In some embodiments, the feed material source 9 may include particulate material stored in a hopper or other storage container, or may be a grinding device configured to grind the feed material before it is fed to the calciner. Such solid particulate feed material may include dust and large-sized solid particles. The size range of the particulate feed material may be, on average, from 50 micrometers to 2,000 micrometers. Alternatively, the size range of the particulate feed material may be, on average, less than 2,000 micrometers. For example, in some embodiments, the particle size range of the solid particulate feed material to be calcined may be between 5 and 500 micrometers, between 5 and 30 micrometers, or other suitable size ranges. In some embodiments, the feed material may have an average particle size of 2,000 micrometers and a maximum particle size of 5,000 micrometers or less. Such embodiments can also include a minimum particle size that is 5 micrometers or greater (eg, the size range can be from 5 micrometers to 5,000 micrometers).

[0078] Calciner 11 can operate such that the solid particulate feed material fed into flame 3F, then traveling through the remainder of calciner 11 and to an outlet of calciner 11, can be calcined from CaCO to form CaO or Ca(OH). The calcined material output from calciner 11 to filtration device 12 can include, for example, primarily CaO or primarily Ca(OH). In some embodiments, the calcined material output from the calciner can be greater than 50 weight percent (wt%) CaO, greater than 75 wt% CaO, greater than 90 wt% CaO, or greater than 95 wt% CaO, or between 90 wt% CaO and 100 wt% CaO (e.g., between 95 wt% CaO and 98 wt% CaO).

[0079] Some embodiments of the calciner 11 can be operated such that Ca(OH) can be formed through operation of the calciner 11 and burner 3 without a subsequent hydration step (e.g., exposing CaO to water). For example, the calcined material output from the calciner 11 can be primarily Ca(OH). For example, the calcined material output from the calciner 11 can be greater than 50 wt.% Ca(OH), greater than 75 wt.% Ca(OH), greater than 90 wt.% Ca(OH), or greater than 95 wt.% Ca(OH), or between 90 wt.% Ca(OH) and 100 wt.% Ca(OH) (e.g., between 95 wt.% Ca(OH) and 98 wt.% Ca(OH)). The formed Ca(OH) can be formed through operation of the calciner 11 and burner 3 without a subsequent hydration step (e.g., exposing CaO to water in a downstream process).

[0080] The formation of Ca(OH) via calcination may be provided due to the formation of water that may occur during the combustion of fuel to form the flame 3F provided by the burner 3. The chemical reaction that may occur in such calcination is believed to be CaCO → CaO + CO → CaO + (H2O) → Ca(OH)2. The water (H2O) may be water from the combustion of the fuel and water that may be present in or included with the feed material.

[0081] For feedstocks that use other types of carbonate materials (e.g., dolomite and / or magnesium carbonate), the calcined material can have different compositions. For example, the calcined feedstock output from calciner 3 can be MgO or Mg(OH)2, or can include a combination of Ca(OH)2 and Mg(OH)2, a combination of CaO and MgO, or a combination of Ca(OH)2, Mg(OH)2, CaO, and MgO. In such an embodiment, the calcined material output from the calciner 11 may be greater than 20 wt.% Mg(OH) and greater than 50 wt.% Ca(OH), between 5 wt.% Mg(OH) and 30 wt.% Mg(OH), and between 70 wt.% Ca(OH) and 95 wt.% Ca(OH), or another suitable composition having a calciner output concentration of Mg(OH) and Ca(OH), or a calciner output concentration of MgO, CaO, Mg(OH), and Ca(OH).

[0082] As another example, in embodiments that may utilize only magnesium carbonate material as a feedstock type, it is contemplated that the calcined feedstock output from calciner 11 may be greater than 50 wt.% Mg(OH), greater than 75 wt.% Mg(OH), greater than 90 wt.% Mg(OH), or greater than 95 wt.% Mg(OH), or between 90 wt.% Mg(OH) and 100 wt.% Mg(OH) (e.g., between 95 wt.% Mg(OH) and 98 wt.% Mg(OH)), or may include a calciner output concentration that includes concentrations of MgO and Mg(OH).

[0083] In embodiments that form Mg(OH), it is contemplated that the formed Mg(OH) may be formed through operation of the calciner 11 and burner 3 without a subsequent hydration step (e.g., exposing MgO to water in a downstream process). The formation of Mg(OH) via calcination may be provided due to the formation of water that may occur during the combustion of fuel to form the flame 3F provided by the burner 3. It is contemplated that the chemical reaction that may occur in such calcination may be MgCO → MgO + CO → MgO + (H2O) → Mg(OH). The water (H2O) may be water from the combustion of the fuel and water that may be present in or included with the feedstock.

[0084] Embodiments of the apparatus and process for calcining a feedstock may also provide improved CO2 capture. For example, calcination of a feedstock may be carried out such that greater amounts and / or higher concentrations of CO2 are released from the feedstock during calcination, whereby the CO2 can be captured as a product via CO2 capture device 23. Embodiments may be configured to provide improved calcined material output and improved CO2 production, in the case of embodiments designed to provide both a CO2 product and a calcined material product.

[0085] Experiments and Simulations An exemplary embodiment of an apparatus for calcining a feedstock containing CaCO3, employing an exemplary embodiment of the process of the present invention for calcining the feedstock, was utilized in a sealed test to evaluate the performance of the apparatus and process. Burner 3 was operated during the test such that the preselected calcination temperature range within calciner 11 was 1,700°F to 1,900°F (926°C to 1,038°C). The fuel used was natural gas, the oxidant used was 90 to 99.99% oxygen by volume, and the particle carrier gas was 30% to 45% oxygen-enriched air by volume.

[0086] The test results are shown in Table 1 below. Scanning electron microscope images of Samples 1-3 obtained from this test are also shown in Figures 6-8. Sample 1 (shown in Figure 6) is an image of the raw feed material containing CaCO3 used in the test. Sample 2 (shown in Figure 7) is partially calcined material extracted from flame 3F of burner 3 obtained from the first stage F1 of the calcination test. Sample 3 (shown in Figure 8) is fully calcined material obtained from the outlet of calciner 11 after the second stage F2 of the calcination test. A residence time of 30 seconds was used in the experiment conducted. [Table 1]

[0087] Table 1 above shows the crystalline composition of the solid particle material that was calcined during testing. This data was obtained via X-ray powder diffraction (XRD) analysis of the sample. The diffraction peaks in the XRD data were matched to reference patterns, as shown in Figures 9-11. The crystalline structures of the identified phases were used to refine the relative composition of the crystalline portion of the sample. The amorphous content of the sample is unknown. The intensities calculated from the refined sample model are: Fits to the observed XRD data are shown in Figures 12-14. As noted above, Sample 1 is the raw material before it is calcined, Sample 2 is the partially calcined material taken from within the flame 3F of burner 3 during the first stage F1 of calcination, and Sample 3 is the calcined material output from the outlet of calciner 11 after being released from the outlet of the calciner after the second stage F2 of calcination.

[0088] Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM / EDS) images of Samples 1 through 3 are shown in Figures 6 through 8. These images were obtained at a magnification of 12,0000x and an accelerating voltage of 2 kV. Figures 6 through 8 are based on images obtained at a scale of 4.00 micrometers (µm).

[0089] As can be seen from the above results, testing showed that a feed material of greater than 95 wt. % CaC0 can be calcined to a calcined material containing greater than 97.5 wt. % Ca(OH) without exposure to water downstream of the calciner 11. Such results demonstrate that embodiments can provide improved calcination of materials at significantly shorter residence times.

[0090] As can be seen from Figure 6, the feed material had a smooth morphology / surface texture. In contrast, Samples 2 and 3, as shown in Figures 7-8, had a nodular appearance, indicating that a significant amount of CO2 was extracted from the feed material via calcination. These resulting images confirm the XRD data obtained from testing, which indicates highly efficient calcination of the feed material, which may result in significant formation of CO2 in the gas output from the calciner for downstream use in carbon capture. Testing showed that in addition to improved calcination, improved CO2 production and capture can be obtained with embodiments of the process and apparatus of the present invention. In addition to the compositional analysis described above, these images indicate that embodiments may provide improved CO2 production to provide improved CO2 yield in addition to improved calcination performance.

[0091] Simulation work was also performed on an exemplary embodiment of the apparatus and process of the present invention for calcining materials. In the simulated embodiment, burner 3 was operated to receive 6.96 MMBTU / hr of natural gas, 15,000 standard cubic feet per hour (SCFH) of oxygen, and 1.853 tons / hr of CaC0 particulate material. In this simulated embodiment, all of the CaC0-containing feed material was passed through the burner to be delivered to calciner 11. Operation of this simulated embodiment resulted in the formation of 1.0 ton / hr of lime (CaO) and 1.161 tons / hr of CO.

[0092] Furthermore, these simulation results showed that embodiments can provide significant improvements in operational performance using smaller equipment adapted to the relatively short residence times available for firing (e.g., residence times of less than 5 minutes, less than 7 minutes, less than 3 minutes, less than 1 minute, etc.).

[0093] Embodiments of the apparatus and process of the present invention may be utilized such that smaller equipment may be used to calcine the feedstock. Because shorter residence times may be required, smaller equipment may be used. This helps to significantly reduce capital and construction costs associated with building a calcination facility, for example. Furthermore, the small footprint that such embodiments may have may reduce operation and maintenance costs.

[0094] Embodiments that do not use air as an oxidant, or that use less air compared to conventional systems, may also have an improved ecological impact by avoiding and / or reducing the formation of nitrous oxide. Such embodiments may also (or alternatively) use simpler exhaust scrubbing devices to remove such undesirable elements from the exhaust gases before such gases are released into the atmosphere.

[0095] As discussed above, embodiments can also be provided such that Ca(OH) and / or Mg(OH) can be formed without the use of water in a separate processing step (e.g., a hydration step). Such a separate processing step can include, for example, a hydration step, which can occur after lime is formed via calcination. This can provide further improved ecological outcomes during operation by avoiding the need to use water and / or form wastewater that may need to be treated. Thus, it should be appreciated that embodiments can provide improved ecological impact in addition to improved operations and reduced costs.

[0096] It should be understood that embodiments of the apparatus 1 for calcining a feed material and embodiments of the process for calcining a feed material can be adapted to meet a particular set of design criteria. Also, (and as discussed above) the apparatus 1 for calcining a solid particulate feed material (e.g., calciner, calcination system) and burner 3 that may be incorporated into such devices can be configured to include process control elements (e.g., temperature and pressure sensors, flow sensors, an automated process control system having at least one workstation including a processor, non-transitory memory, and at least one transceiver for communicating with sensor elements, valves, and controllers for providing a user interface to the automated process control system, which may be run on the system's workstation and / or another computing device) positioned and configured to monitor and control operation.

[0097] Furthermore, it is contemplated that certain features described either individually or as part of an embodiment may be combined with other individually described features or parts of other embodiments. Accordingly, elements and acts of various embodiments described herein can be combined to provide further embodiments. Thus, while certain exemplary embodiments of a process for calcining a feed material, an apparatus for calcining a feed material, and methods of making and using the same have been shown and described above, it is to be clearly understood that the invention is not limited thereto and may be variously embodied and practiced within the scope of the following claims.

Claims

1. 1. A process for calcining a feedstock, comprising:

1. A process comprising: feeding solid particulate material to a flame formed within a calciner such that the solid particulate material passes through the flame as it moves through the calciner to an outlet of the calciner.

2. 10. The process of claim 1, wherein the solid particulate material has a residence time for firing of 5 minutes to 5 seconds, 3 minutes to 5 seconds, 10 seconds to 30 seconds, or 5 seconds to 1 minute.

3. said supplying said solid particulate material to said flame comprising: moving the solid particulate material into a burner for feeding into the calciner via the burner; and / or 10. The process of claim 1, comprising moving the solid particulate material into the calciner adjacent the flame so that the solid particulate material passes through the flame.

4. 10. The process of claim 1, comprising supplying a stream of fuel and at least one oxidant to the burner for forming the flame in the kiln.

5. 5. The process of claim 4, wherein the flame facilitates calcination of the solid particulate material at a preselected calcination temperature range of 815°C to 2,205°C, 815°C to 1,370°C, 815°C to 1,650°C, 925°C to 1,650°C, or 925°C to 1,370°C.

6. The calcined material contained 70 weight percent (wt%) Ca(OH) ２ ~100 wt% Ca(OH) ２ , 80 wt.% Ca(OH) ２ ~100 wt% Ca(OH) ２ , or 90% by weight of Ca(OH) ２ ~100 wt% Ca(OH) ２ 2. The process of claim 1, comprising:

7. 10. The process of claim 1, wherein the feedstock consists of at least 70 weight percent carbonate material and no more than 30 weight percent impurities.

8. 10. The process of claim 1, wherein the feedstock has an average particle size of from 50 micrometers to 2,000 micrometers and a maximum particle size of not more than 5,000 micrometers.

9. 10. The process of claim 1, further comprising filtering a flow output from the outlet of the calciner to separate the solid particulate material from combustion gases formed from the formation of the flame, the solid particulate material separated from the combustion gases being calcined material.

10. passing the solid particulate material through at least one dryer prior to said feeding of the solid particulate material to the flame in the calciner; 2. The process of claim 1, further comprising: transferring the combustion gas to the dryer and drying the solid particulate material in the dryer before the combustion gas is transferred to a carbon capture system to capture carbon dioxide from the combustion gas.

11. filtering the flow output from the outlet of the calciner to separate the solid particulate material from combustion gases formed from the formation of the flame, the solid particulate material separated from the combustion gases being calcined material; and cooling the stream output from the outlet of the calciner prior to said filtering.

12. 12. The process of claim 11, wherein prior to said filtering, a cooling medium for said cooling of said stream output from said outlet of said calciner comprises carbon dioxide.

13. 1. An apparatus for calcining a feed material, comprising: A firing furnace; and at least one burner positioned adjacent to an entrance portion of the calciner, the burner being positioned such that solid feed material supplied to the calciner can pass through the burner and through at least one flame formed in the calciner for calcining the solid feed material, wherein the calciner and the at least one burner are arranged and positioned such that the solid feed material can move through the at least one flame to an exit of the calciner for calcining the solid feed material.

14. 14. The apparatus of claim 13, comprising at least one filtering device connectable to the outlet of the calciner to receive the solid feed material and combustion gases from the outlet of the calciner and to filter solid particles of the solid feed material from the combustion gases.

15. 14. The apparatus of claim 13, wherein the at least one burner and the calciner are arranged and configured so that the solid feed material has a residence time for calcination of 5 minutes to 5 seconds, 3 minutes to 5 seconds, 10 seconds to 30 seconds, or 5 seconds to 1 minute.

16. 14. The apparatus of claim 13, wherein the at least one burner is connectable to a source of fuel, at least one source of oxidant, and at least one source of the solid feed material such that at least a portion of the solid feed material is supplyable to the burner for being fed into the flame.

17. 14. The apparatus of claim 13, wherein the calciner is connectable to at least one source of solid feed material such that at least a portion of the solid feed material can be fed to the calciner for movement into the flame for partial calcination in the flame in a first stage of calcination before exiting the flame and moving toward the outlet of the calciner for further calcination in a second stage of calcination.

18. 14. The apparatus of claim 13, wherein the at least one burner and the calciner are arranged and configured such that the flame facilitates calcination of the solid feed material at a preselected calcination temperature range of 815°C to 2,205°C, 815°C to 1,370°C, 815°C to 1,650°C, 925°C to 1,650°C, or 925°C to 1,370°C.

19. 14. The apparatus of claim 13, comprising a carbon capture system positioned downstream of the outlet of the calciner for capturing carbon dioxide from the combustion gases output from the outlet of the calciner.

20. 1. A baking system comprising: a firing furnace having an outlet in communication with the chamber; at least one burner connected to the kiln to form at least one flame within the chamber for firing at a preselected firing temperature range of 815°C to 2,205°C; at least one filtering device connected to the outlet of the kiln to receive the calcined material entrained in the combustion gas from the kiln for separating the calcined material from the combustion gas; a carbon capture system connected to the at least one filtration device to receive the combustion gas for removal of moisture from the combustion gas and capture of carbon dioxide from the combustion gas; a source of solid particulate feed material connectable to the at least one burner and / or the calciner to supply the solid particulate feed material into the at least one flame for a first stage of calcination of the solid particulate feed material, and the calciner is sized and configured to move the solid particulate feed material from the flame to the outlet within the chamber of the calciner for a second stage of calcination of the feed material such that a preselected residence time of the solid particulate feed material for calcination to form the calcined material is greater than 5 seconds and less than or equal to 5 minutes.

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