Process and method for firing materials - Patents.com

Abstract

A system for calcining powder material comprising a plurality of vertical reactor tubes, wherein the falling powder is heated around a heating zone by radiation from the external heating wall of the reactor tube, and the calcination process of the powder may be a reaction that releases gas or induces a phase change, and the average velocity of the falling powder particles while passing through the reactor tubes is not more than 1.0 m / s, and the powder material flux in each tube is preferably 0.5-1 kg m -2 ·s -1 The length of the heating zone is in the range of 10 to 35 m.

Description

[Technical field]

[0001] The present invention relates broadly to a means for calcining a material in a continuous process, where calcination as described herein is a reaction and / or phase change induced by heating the material.

[0002] There are many processes that have been developed to calcinate materials, and they have been developed to process specific materials with specific fuels. The present disclosure relates to a means of rapid calcination known as flash calcination, which uses indirect heating to provide the energy for the reaction of powdered materials. [Background technology]

[0003] Most of the prior art techniques for calcination use direct heating of the material by combustion gases, whereas indirect heating transfers heat from the reactor wall, typically by radiative heat transfer from an external combustor through a steel tube. Indirect heating processes generally have three applications: (a) to produce calcined materials with higher reactivity than direct heating, due to short residence times and temperature control within the reactor, which reduces internal sintering, and / or (b) to separate the combustion process from the reaction process, so that the calcined products are not contaminated by combustion impurities, and / or (c) to separate gases from the combustion and reaction processes, so that the reactions can be controlled, for example by controlling the oxidation state, and / or (d) to use CO as the calcination reaction to produce oxides. 2 Processing carbonate materials that release CO 2 (which allows the gas to be captured as a pure gas stream).

[0004] CO 2 Regarding the capture of CO2 from such a combustion process, there are two sources of emissions. The first source is CO2 released from the combustion of carbon-based fuels. 2 and is referred to herein as "combustion CO 2 The second source is called "process CO" which comes from reaction processes, generally carbonate materials. 2The low-emissions firing process reduces the amount of CO 2 and Process CO 2 The aim of the project is to reduce both CO2 emissions and CO2 emissions from the fuel side. 2 Global efforts to reduce emissions are focused on reducing CO2 emissions by reducing the amount of fuel used. 2 and Process CO 2 CO per tonne of product, including both 2 It is expected that emissions will be measured by the emission intensity, which is the number of tons of emissions. It is necessary to reduce the emission intensity of the products produced in the firing process.

[0005] Combustion CO 2 There are a number of established ways to reduce emissions. One way to reduce combustion emissions is to indirectly heat the kiln using "renewable electricity" generated from wind, solar or other processes. The cost of generating renewable electricity is falling rapidly and could become affordable as a commodity product. Other methods use low-emission gas-combustion processes. One method is to use non-carbon-based fuels such as hydrogen, for example fuels derived from the "electrolysis" of water, or CO 2 or the use of carbon-based fuels that have been treated by "pre-combustion" capture to remove CO. 2 One method is to treat the flue gas from the combustion of carbon-based fuels with sorbents such as amines, bicarbonates, metal oxides, and hydrotalcites to remove CO, a process known as "post-combustion" capture. Another method is to use sorbents such as amines, bicarbonates, metal oxides, and hydrotalcites to remove CO, which is easily captured. 2This is a method of using oxygen instead of air to burn carbon-based fuels in a process called "oxy-fuel combustion" to produce flue gases with a high percentage of CO2. It will be apparent to one skilled in the art that combustion emissions can be reduced by using renewable electricity, or electrolysis, or pre-combustion capture, or post-combustion capture, or oxy-fuel combustion, or a combination of these. In most firing processes that use combustion gases, the hot flue gases are used to transfer energy directly to the material by direct heating. Therefore, process emissions are mixed with the flue gases and are a source of process CO2. 2 Extraction of CO increases the cost and complexity of reducing process emissions. 2 It also offers the flexibility to reduce emissions, as it not only captures the heat as a pure gas vapor, but can use any of the low-emission methods mentioned above to provide the heat.

[0006] The material that generates process emissions when fired is limestone CaCO 3 , Dolomite MgCO 3 ·CaCO 3 , Magnesite MgCO 3 Carbonate materials such as marls and other mixed metal carbonates (siderite, FeCO 3 impure limestone, including limestones such as mercury, mercury, mercury-containing limestones, and synthetic carbonate compounds produced for the production of certain oxide materials (e.g. manganese carbonate MnCO, produced as an intermediate in the production of metals and battery materials). 3 ), as well as CO 2 There is a wide range of materials that are processed by calcination for various industrial purposes, and these are process CO 2 Generate.

[0007] To mitigate climate change, we are promoting the use of process CO2 emissions to reduce emissions from the firing of materials. 2 Emissions and Combustion CO 2Either or, preferably, both emissions need to be captured. For example, the cement industry has many ways and many CO 2 CO from limestone calcination through capture methods 2 The former methods include using biomass, waste, and renewable electricity as fuels, while the latter methods include the processes described herein as amine capture, oxyfuel combustion, calcium looping, and direct separation. The most desirable solution for reducing emissions is CO 2 Lowest cost of capture (avoided CO 2 Many of the proposed capture processes, such as the amine process or oxyfuel process, require novel chemical and physical processes, which means that CO 2 The cost of capture is significant. With calcium looping, the high mass flow rates and energy recovery are barriers to use. A common theme with each of these processes is the increased complexity and cost of their implementation. An alternative approach, direct separation, as described by Sceats et al. in WO 2015 / 077818 "Process and Apparatus for Manufacture of Portland Cement" and references therein, can be used to reduce process CO emissions without additional energy penalties or the use of new materials. 2 This approach uses indirect heating of the calciner, so that the process gas stream from the processing of carbonate minerals contains small amounts of process CO2 impurities due to volatilization of trace elements. 2 The general approach to calcining carbonate materials using indirect heating is described in WO 2016 / 077863, "Process and Apparatus for Manufacture of Calcined Compounds for Production of Calcined Products," by Sceats et al., and references therein, where the indirect heating process is extended to the use of multiple reactor segments containing different material and power segments.

[0008] It is noted that the invention related to the direct separation reactor described in WO 2015 / 077818 and WO 2016 / 077863 and references therein is an indirectly heated flash calcination process, the timescale of which is generally in the range of 10 to 50 seconds. WO 2015 / 077818 and WO 2016 / 077863 and references therein generally include a general requirement that the input particle size is typically less than about 100 microns, so that the degree of calcination, defined herein as the proportion of carbonate that is converted to oxide in the reactor within this residence time, is sufficient for the application of the calcined product. One of the variables that controls the calcination process in a direct separation reactor is the wall temperature distribution, so residence time and the average value of this wall temperature are typically referenced as key variables in reactor design. In a direct separation reactor, particles preferably flow downwards under gravity, the residence time is related to the terminal velocity of the particle size distribution (PSD), and the acceleration of particles falling under gravity is balanced by gas-particle friction, which depends on the direction of gas flow.

[0009] In general, with respect to the residence time and temperature of the reactor, the degree of calcination of the material is preferably at least 95%, and most preferably at least 97% or more. However, for cement powder, it may be lower, about 85%, because the subsequent clinkerization process may require endothermic loads, such as when using a rotary kiln to produce clinker. There is a need for a direct separation process that can control the residence time and temperature in the reactor segments to achieve the desired degree of calcination of the material. The invention of the present disclosure is directed, in part, to increasing the residence time and temperature of the direct separation reactor.

[0010] For PSD, three values ​​were determined from the measured cumulative volume distribution: 10% by volume of particles were d 10 d as the diameter which is less than 10 , 50% by volume is d 50 d as the diameter which is less than 50, and 90% by volume is d 90 d as the diameter which is less than 90 Calcined powders of carbonate materials have many uses, and the most preferred d 50 The size is greater than about 100 microns, as described in the prior art referenced above. Specifically, the product has a size of about d between 0.1 and 300 microns. 10 ~d 90 The range covered is 0.01 to 0.1, with each product having a given PSD within this range.

[0011] d 50 Powder materials with diameters greater than 100 microns are 50 These materials are easier to handle than smaller materials and the products are commonly used in certain powder applications. There is a need to extend direct separation technology to be able to produce such powdered materials in this range.

[0012] Other applications require material in the form of granules in the millimeter size range, preferably in the form of mixed material granules, especially in applications in mineral processing (where entrainment of such products in the gas stream is undesirable, such as slagging for the production of metals like iron, aluminum, magnesium), and in cement production (where clinker formation occurs by reaction between the bonded particles in the granules in a subsequent process step to form clinker), and in refractory products (where briquettes are produced before sintering). To enable the production of such granulated materials, the direct separation technology needs to be extended, including its integration into the production of granulated products.

[0013] Those skilled in the art will appreciate that the PSD of the calcined material will vary considerably in many applications. In particular, the need to reduce emissions associated with the production of such products necessitates the application of direct separation reactors to process carbonate materials of a wide range of particle size diameters. Larger particles will fall through the direct separation reactor faster than smaller particles, resulting in a shorter residence time for the larger particles relative to the smaller particles. In some cases, it may be practical to extend the length of the direct separation reactors described in the prior art referenced above to achieve this desired degree of calcination. However, it is generally preferred to use a more compact direct separation reactor. The presently disclosed invention is directed to a calcination process capable of processing larger particles than those previously disclosed for direct separation reactors.

[0014] The direct separation reactors described in WO 2015 / 077818 and WO 2016 / 077863 are described as single tube reactors, with input material typically being on the order of 8-10 tonnes per hour. For large scale manufacturing processes such as cement, it is desirable to scale up the reactor to around 200 tonnes per hour. There is a need to adapt the direct separation reactor for such a scale-up so that the benefits of the process can be delivered to mass production.

[0015] The disclosed invention is directed to the use of CO in the calcination of primarily carbonate materials, particularly limestone and cement raw meal. 2 Although the invention is directed to reducing CO emissions, the reaction is either a phase change or a CO 2 The present invention can also be applied to the calcination of other materials that release gases other than carbon dioxide. Examples of such calcination processes include the removal of moisture and water of hydration by the generation of steam, and the volatilization of acid gases such as sulfur compounds, ammonia, and hydrochloric acid.

[0016] The project leading to this application has received funding from the European Union's research and innovation programme Horizon 2020 under grant agreements No. 654465 and 884170. (background)

[0017] The invention described in this disclosure is primarily directed to the separation of calcium carbonate (CaCO 3 The invention was derived from the observation and understanding that calcining a material containing arsenic (Ar) to produce lime (CaO) produces a slag. Such invention described herein can be considered an improvement over WO 2015 / 077818 and WO 2016 / 077863 and references therein for processing such materials. Furthermore, the disclosed invention can be applied to direct separation reactors to scale up processes, facilitate integration of direct separation reactors into industrial processes, or process other materials in direct separation reactors for any purpose.

[0018] Those skilled in the art will appreciate that in the processing of calcium carbonate-containing materials, including limestone, dolomite and cement powder, freshly calcined lime particles are "sticky". Early references to this property appear in the historical literature of lime burners, the results of which have influenced the design of modern manufacturing processes that produce large quantities of CaO. There is a great deal of literature on the subject, which is summarized below.

[0019] The stickiness of lime is related to the formation of particle agglomerates, the formation of deposits on cold surfaces, the adhesive properties of the bed of material, and product transport challenges. The physical cause of stickiness is related to the high surface energy of CaO grains generated at the calcination reaction front moving within the grain. Without being limited by theory, it is believed that the calcination reaction creates small particles of the order of 20 nm in size with a surface area of ​​100 m 2CaO grains exceeding 500 nm / g are produced. These small grains have a high surface energy, which is naturally reduced by the sintering process at high temperatures. In this process, the grains grow to over 100 nm by a process known as Ostwald ripening, which is initiated by the formation of necks between adjacent CaO grains and the subsequent diffusion of CaO through these necks, where the smaller grains are absorbed by the larger grains. This coarsening process reduces the surface energy as the grains increase in size. In terms of the pores between the grains, there is a shift in porosity from mesopores of 5-10 nm to macropores of over 100 nm. The literature suggests that such sintering is driven not only by the temperature but also by the CO 2 and H 2 It has been stated that the partial pressure of O also increases the sintering rate through various mechanisms because sintering is catalyzed by these gases. This catalysis allows CaO to be rapidly mobile on micron length scales. The diffusion of CaO is important for processes such as ceramic and cement production, slagging of minerals, and its impact on flash firing, as discussed below.

[0020] The cause of such "stickiness" of lime particles is the development of necks between colliding particles, or between particles attached on a surface, or even between particles packed in a bed, lowering the surface energy. The process of physical sintering of grains within a particle is indistinguishable from adhesion of particles in physical contact. In the literature on ceramics, cement, and slagging processes, the term "sintering" is applied to both intra- and inter-particle processes. In the present invention, the relevant aspect of stickiness is the process of "agglomeration" whereby particles adhere during the firing process to an extent that the processing of the aggregates through the reactor is significantly different from the individual particles, and furthermore, a process of "cascade agglomeration" occurs whereby aggregates adhere to each other. Without being limited by theory, it is understood that (a) agglomerates form from particle-particle collisions within clusters of particles that are generated in a direct separation reactor to minimize gas particle friction; (b) agglomerates form more readily under conditions of greater gas-particle turbulence that increases the collision rate between particles within a cluster; (c) the strength of adhesion and its persistence are a result of the sintering process; and (d) the persistence of agglomerates can have a significant impact on the firing process.

[0021] As it pertains to direct separation reactors, the prior art on CaO sintering includes CO 2 Catalytic sintering of CaO by sintering has also been described, where the initial stages of sintering are carried out at temperatures above about 800° C. and at CO2 above about 5 kPa. 2 This sintering time occurs within 30 seconds at partial pressure of CO 2 This is comparable to the 10-50 second residence times typically used in direct separation reactors, where the partial pressure is about 100 kPa and the temperature is about 900°C. The CaO produced in such a direct separation reactor is sintered to a surface area of ​​about 20 m. 2 It is reasonable to expect that the sintering rate will be less than 1 / g. This has been confirmed in direct separation reactors. Since sintering occurs during the residence time of the particles in the reactor, the effect of "stickiness" between particles is also evident, and the CO 2 It is anticipated that the presence of may affect the performance of direct separation reactors in processing materials that produce CaO. This disclosure focuses on inventions that mitigate the adverse effects or exploit those effects to create new materials.

[0022] One object of the present invention is to provide one or more means for optimizing the design of a direct separation tube reactor to control the effects of lime stickiness.

[0023] Another object of the present invention is to provide a means to scale up the direct separation reactor to larger production capacities.

[0024] Another object of the present invention is to describe the use of the present invention for integrating direct separation reactors into industrial applications, specific applications include the production of Portland cement, iron, aluminum and magnesium metals.

[0025] Another object of the present invention is to apply these inventions to the processing of other materials, where simplification of the process in terms of operation and complexity, or improvement of the properties of the material, would be advantageous.

[0026] Any discussion of prior art throughout this specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field. (Summary) The invention of this patent generally relates to improvements in direct separation technology. (a) Such invention includes a system for sintering powdered material comprising one or more reactor tubes in which the falling powder is heated primarily by radiation from the external heated walls of the tubes, the powder sintering process may be a reaction that releases a gas, a reaction that induces a phase change, or both, the average velocity of the powder while passing through the reactor tubes is 1.0 m / s or less, preferably 0.2 m / s or less, and the powder material flux in each tube is preferably between 0.5 and 1 kg m -2 ·s -1 and the length of the heating zone ranges from 10 to 35 m. (b) A means for treating large particles over 100 μm using countercurrent flow of particles and gas; (c) A means for reducing turbulence of gas particles by using co-flow of particles and gas to reduce agglomeration and clustering; (d) means for injecting particles into the direct separation reactor using a countercurrent pipe system that cools the calcined particle stream from the direct separation reactor and heats the ambient particle stream, and in the case of lime, a preheating system is used to partially calcinate and passivate the particles to inhibit agglomeration and fouling as they are injected into the direct separation reactor; (e) A means for efficient external heating of the reactor walls using tightly integrated combustor segments, flameless combustors with a variety of fuels, and electrical heating, and in the case of carbon-based fuels, a post-combustion process is used to reduce CO 2 and reduce energy consumption and CO 2 Measures to minimize emissions. (f) Segmented tubes can be used for (i) process gas pressure switching to optimize process energy consumption, (ii) hot gas and fuel / air injection, and (iii) optimized chemical reaction sequences to produce products (e.g., CaCO 3 From Ca(OH) 2 (production), enabling, means. (g)CO 2 A method for thermally granulating lime, taking advantage of the adhesive properties of the CaO in the lime, including mixing the lime with other minerals, so that the granules can be used in industrial processes where slagging or clinkering is important (such as the production of iron and aluminum using CaO, or magnesium metal from dolime MgO·CaO). (h) A means to scale up the process using multiple tubes. Summary of the Invention [Problem to be solved by the invention]

[0027] The first problem to be solved is the separation of particles containing CaO, especially CO 2The objective of this study was to optimize a direct separation reactor for processing materials that produce CaO particles in the presence of

[0028] The second challenge to be overcome is to optimize the direct separation reactor in order to scale up the process to larger throughputs.

[0029] A third problem to be solved is the integration of direct separation reactors into many industrial processes.

[0030] The fourth problem to be solved is the improvement of direct separation reactors for calcining a wide range of materials. [Means for solving the problem]

[0031] In a first aspect of the invention, several strategies are described to reduce the formation of CaO-induced agglomerates of particles injected into a direct separation reactor, to reduce fouling of metal surfaces to which heat is transferred, and to reduce the tendency of beds of these particles to resist fluidization for transport. Three solutions are described. The first solution is to process larger CaO particles, taking advantage of the observation that calcining larger particles reduces agglomeration. The second solution is to reduce the agglomeration of CaO particles by minimizing the frequency of collisions between particles. The third solution is to reduce the tendency of such CaO particles to stick together upon collision.

[0032] In a second aspect of the invention, a means is described for promoting agglomeration of CaO particles produced from a direct separation reactor using the invention described in the first aspect to produce products requiring granules of material for use in a subsequent process. Such processes include the production of Portland cement from calcined cement powder produced in a direct separation reactor, the production of magnesium metal using the Pigeon process from dryme MgO·CaO produced in a direct separation reactor, and the production of low emission lime granules produced in a direct separation reactor (e.g. for injection into slagging processes used in steel and aluminum production to remove impurities such as silicates).

[0033] In the third aspect of the present invention, several strategies are described for integrating a direct separation reactor into an industrial process. These strategies include a means for preheating the input powder using waste heat, a means for injecting the powder into the reactor, a means for providing heat to the reactor wall, a means for extracting the process gas stream from the reactor, a means for minimizing the loss of solids in the exhaust gas, and a means for cooling the product. The main need of this aspect is to provide a strategy for minimizing the energy required to process the material, which is generally fed at ambient conditions, and preferably providing a powder product and an exhaust gas stream at the required conditions with minimal energy consumption.

[0034] In the fourth aspect of the invention, several strategies are described that allow the scale-up of the production capacity of a system using a direct separation reactor. There is a reasonable limit to the diameter of the direct separation reactor tube, related to the penetration depth of radiation into the particle and gas mixture. Therefore, the scale-up of the production capacity is mainly achieved through the array of tubes. Strategies for scale-up include means for distributing preheated solids to multiple tubes, means for heating powders in separate tubes in a furnace from a combustor, and means for collecting powder and gas streams from the reactor tubes for subsequent processing. The main need of this aspect is to provide a strategy that minimizes the energy required to process the material, which is generally provided at ambient conditions, and provides powder products and exhaust gas streams at the required conditions, preferably with minimal energy consumption, and achieves economies of scale.

[0035] In a fifth aspect of the present invention, certain process steps are proposed that facilitate the integration of a direct separation reactor into a manufacturing process, the main application being the production of cement clinker.

[0036] In a sixth aspect of the present invention, there is provided a system for calcining powdered material comprising a plurality of vertical reactor tubes, wherein the falling powder is heated around a heating zone by radiation from an external heating wall of the reactor tubes, the calcination process of the powder may be a reaction releasing a gas or inducing a phase change, the average velocity of the falling powder particles while passing through the reactor tubes is less than or equal to 1.0 m / s, and the powder material flux in each tube is preferably between 0.5 and 1 kg m -2 ·s -1 and the length of the heating zone is in the range of 10 to 35 m.

[0037] Preferably, the powder material comprises a compound or mineral that releases a gas when heated, the gas being at least one selected from the group of carbon dioxide, steam, an acid gas such as hydrogen chloride, and an alkaline gas such as ammonia.

[0038] Preferably, the mineral is limestone or dolomite.

[0039] Preferably, the compound comprises silica and clay and the powder material is raw cement flour for the production of Portland cement.

[0040] Preferably, the particle volume distribution of the powder material is limited to 90% less than 250 μm in diameter and 10% greater than 0.1 μm.

[0041] Preferably, the evolved gas flows upwards in the tube against the flow of the calcined powder, and the gas is exhausted at the top of the system.

[0042] Preferably, the released gases and the gases introduced into the system flow downwardly within the reactor tube along with the flow of calcined powder, with the gases being exhausted at the bottom of the system.

[0043] Preferably, an inner tube is disposed within each tube, the powdered material flows downwards in the reaction annulus together with the evolved gases, at the bottom of the reactor the gas flow reverses and flows upwards through the inner tubes, and the evolved gases and gases introduced into the system are exhausted at the top of the system.

[0044] Preferably, powdered material entrained in the exhausted gas is separated and reinjected into the system.

[0045] Preferably, the injected powder is preheated in a gas-powder preheater system before being injected into the system.

[0046] Preferably, the gas-powder preheater system is one or more refractory heating tubes in which the cold powder material falls through and is heated by the hot ascending gas, and the average velocity of the powder while passing through the preheat tube is less than or equal to 0.5 m / sec.

[0047] Preferably, the powder discharged from the bottom of the system is cooled in a gas-powder cooling system.

[0048] Preferably, the gas-powder cooling system is one or more refractory cooling tubes through which the hot powder material falls through a cooler rising gas, the average velocity of the powder while passing through the cooling tubes being less than or equal to 0.5 m / sec.

[0049] Preferably, the external heating system for externally heating the tube walls is an integrated combustor and furnace system, allowing control of the temperature profile below the heating zone of the system.

[0050] Preferably, the external heating system is a flameless combustion system that allows control of the temperature profile below the heating zone of the system.

[0051] Preferably, the fuel of the external heating system is at least one gas selected from the group of natural gas, synthesis gas, town gas, producer gas, and hydrogen, and the combustion gas is air, oxygen, or a mixture thereof heated from the flue gas of the external heating system.

[0052] Preferably, the CO in the flue gas 2 CO after regeneration combustion 2 The extraction is performed using a capture system, which is at least one selected from the group consisting of an amine sorbent system, a bicarbonate sorbent system, and a calcium looping system.

[0053] Preferably, the external heating system is an electric furnace, with power generated from a hot gas stream or extracted from a grid within the production plant of which the system is a part, and configured to enable control of the temperature profile below the heating zone of the system.

[0054] Preferably, the external heating system is a combination of any one of the external heating systems as defined in claims 14, 15 and 18, which may be applied to different segments of each tube or to different tubes, and operation of the system allows the use of variable combinations of such external heating systems whilst maintaining a continuous production of sintered material.

[0055] Preferably, the powdered material is injected into the reactor tube at several depths.

[0056] Preferably, each tube is divided into a number of segments mounted in series and gas released or introduced at each segment is extracted from that segment using gas blocks between the segments.

[0057] Preferably, the partial pressure of the gas released during firing in the upper segment can be reduced in the lower segment so that the reaction proceeds further by partial pressure drop to achieve a new equilibrium at a lower partial pressure, which includes a drop in the wall temperature of the lower segment so that the thermal energy stored in the partially fired powder from the upper segment is used for firing.

[0058] Preferably, the wall temperature of each segment is increased in each segment starting from the top segment so that the gas released from each segment is a particular gas of the desired purity, and other gases may be added to each segment to promote catalysis of the reaction process and / or sintering of materials during the reaction process.

[0059] Preferably, the system produces sintered MgO for refractory blocks from magnesite.

[0060] Preferably, the system converts limestone or magnesite into Ca(OH) 2 or Mg(OH) 2 Generate.

[0061] Preferably, the system controls the oxidation state of the battery precursor.

[0062] Preferably, each tube is divided into several segments, the gas discharged or introduced in each segment is extracted from that segment using gas blocks between the segments, and a hot gas flow is introduced into the segment to increase the thermal energy of the gas and particles in that segment, augmenting the thermal energy provided by the external heating.

[0063] Preferably, the gas flow contains a combustible fuel and oxygen or air for combustion to induce combustion in that segment and increase the thermal energy of the gases and particles in that segment to augment the thermal energy provided by external heating in that segment or other segments.

[0064] Preferably, the temperature increase due to the combustion is sufficient to induce particle-particle or interparticle reactions typical of subsequent torrefaction or clinkerization reactions in the powder bed formed at the bottom of the segment, and the energy released from the exothermic reaction is capable of maintaining or increasing the temperature of the powder bed such that the induced reaction is fully completed during the residence time in the powder bed.

[0065] Preferably, the preheat temperature of the gas-powder preheater system is in the range of 650-800°C and the partial pressure of the gas released during calcination is less than 15 kPa, so that the powder material is partially calcined and then sintered such that the surface energy of the particles is sufficiently reduced, thereby reducing the tendency of the particles to subsequently bond and agglomerate.

[0066] Preferably, the material is limestone, the calcined material or a mixture of the calcined material and other minerals is introduced into a post-processing system to produce granules of the material, the granules are formed by agitating the powder, the gas environment includes carbon dioxide, and the temperature of the granulator system is adjusted to a temperature below that of the limestone and CO. 2 The temperature range is 650 to 800°C, at which recombination with the metal is suppressed.

[0067] Preferably, the material is first calcined in a first segment using a steel reactor wall to supply heat to the system, and gases released or introduced in each segment are extracted from that segment using a gas block between this first segment and the lower segment, so that a second gas flow of a different gas is injected into the second segment and heat transfer through the reactor wall of the second segment is controlled so that the calcined powder from the first segment reacts with the gas to produce new material compounds.

[0068] Preferably, the powder material is limestone CaCO 3 , or dolomite CaCO 3 MgCO 3 where the calcination product from the first segment is lime CaO or dolomite CaO MgO, and the exhaust gas is CO 2 and the gas injected into the second segment is steam H 2 O, the temperature is controlled by removing heat through the wall as the slaked lime is discharged from the second segment, and the diameter of the tubes in the system is selected to balance heat transfer and reaction rate with residence time at minimum segment length.

[0069] Preferably, the slaked lime or dry lime product is prepared by slaked lime or dry lime synthesis using CO in ambient air.2 It has high reactivity with CaCO 3 or MgCO 3 ·CaCO 3 This product is converted to CO from ambient air in a circulation system. 2 This product is then used along with renewable fuels to remove CO2 from the combustion 2 When combined with the capture of carbon dioxide, the system produces a carbon-negative emissions product.

[0070] Preferably, the reactor tube is vibrated to remove any buildup of solid material adhering to the walls of the system.

[0071] Preferably, heat from the external heating system to each tube is separated by a refractory wall so that the plant can operate efficiently with any number of tubes through the use of refractory materials and energy distribution, including gas and radiation, which controls the exposure of any tube to radiation and the convective transfer of heat so that the temperature profile is controlled within the desired ranges related to thermal stresses in the metal tubes and energy consumption by the system.

[0072] Preferably, the preheater segment and / or the cooling segment require distribution of preheated material from a central preheater to each tube, this distribution being achieved by at least one of the following groups: an L-valve, an assembly of L-valves designed to provide controlled distribution of powder to each tube, an agglomeration system that collects hot calcined material from each tube to a central cooling system, and a central downstream processing system such as a kiln, and the agglomeration is achieved by a system of gas slides where the flow of hot calcined powder is controlled to provide a continuous flow of material.

[0073] Solutions to the problem can be derived from many of these aspects.

[0074] Further aspects of the invention will become apparent from the description and drawings.

[0075] Embodiments of the present invention will be better understood and readily apparent to those skilled in the art from the following description, given by way of example only, in conjunction with the drawings in which: [Brief description of the drawings]

[0076] [Figure 1] FIG. 1 is a schematic diagram of an exemplary embodiment in which the residence time of preferably large particles in a direct separation reactor is extended by countercurrent flow of process gas to reduce the terminal velocity of the particles. The undesirable effects of CaO-induced particle-particle bonding are mitigated by using sufficiently large particles that have a low tendency to bond.

[0077] [Diagram 2] FIG. 1 is a schematic diagram of an exemplary embodiment for preferably calcining small particles, where CaO induced particle-particle bonding is limited by using co-flow of particles and process gas, with gas-particle separation occurring at the bottom of the reactor by a separator.

[0078] [Diagram 3] FIG. 1 is a schematic diagram of an exemplary embodiment for preferably calcining small particles, where CaO induced particle-particle bonding is limited by using a direct separation reactor design with a central tube, where the reaction occurs in low turbulence co-flow of particles and gas flowing below the annulus, the process gas is exhausted through the central tube, and gas-particle separation occurs at the bottom of the reactor by reversing the direction of gas flow.

[0079] [Figure 4] FIG. 4 is a schematic diagram of an exemplary embodiment for preferably calcining small particles, where partial pre-calcination, controlled agglomeration and sintering are performed prior to injection into the reactor, further reducing CaO induced particle-particle bonding over the designs described in FIGS. 1-3.

[0080] [Diagram 5] FIG. 13 shows that the powder is injected into the reactor zone at several depths to mitigate the effects of agglomeration.

[0081] [Figure 6] FIG. 6 is a schematic embodiment of agitating powder exhaust from any of the direct separation reactor configurations of FIGS. 1-5 to produce agglomerate spheres of a desired size, where the compressive strength of the granules is strong enough for a particular application.

[0082] [Figure 7] FIG. 1 is a schematic diagram of an exemplary embodiment in which partially calcined powder from a first reactor segment is injected into a second reactor segment and a gas stream is injected into the second reactor segment.

[0083] [Figure 8] 1 is a schematic diagram of an exemplary embodiment for particular application in the production of cement clinker, where the powder exhaust from a direct separation reactor is treated in several steps to produce cement clinker by directly heating the falling powder to flash heat it and provide sufficient energy to initiate the clinkerization reaction, which is heated at the bottom of the reactor and falls into a moving bed where the exothermic clinkerization reaction proceeds and further heats the moving bed, where clinker is rapidly formed. Other industrial applications of this general process are described.

[0084] [Figure 9] 2 is a schematic illustration of an exemplary embodiment of the countercurrent direct separation reactor of FIG. 1 for processing limestone, where furnace heat is provided by a flameless regenerative combustion process, fuel is syngas produced from biomass, CO2 is extracted from flue gas, and heat from the product solids and process gas streams is used to preheat the input powder using a countercurrent heat exchanger. The intent of this embodiment is to show that the system can provide high thermal efficiency with complete process and capture of combustion CO2, providing an overall carbon negative emissions product.

[0085] [Figure 10]FIG. 11 is a schematic diagram of an exemplary embodiment of a direct separation reactor module in which the reactors of any of FIGS. 1-10 are housed in a single furnace, with radiative and convective coupling of the tubes controlled by the use of refractory elements within the furnace, and with the majority of the product preheating and cooling accomplished using the auxiliary equipment described in FIG. 10 for each tube.

[0086] [Figure 11] FIG. 12 is a schematic diagram of an exemplary embodiment of a direct separation reactor module in which the reactors of any of FIGS. 1-11 are housed in a single furnace, the radiative and convective coupling of the tubes is controlled by the use of refractory elements within the furnace, and preheating and post-processing of materials is performed using a modular system that requires distribution of preheated and calcined powders to and from the tubes. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0087] Preferred embodiments of the invention will now be described with reference to the accompanying drawings and non-limiting examples.

[0088] Regarding the first aspect related to the reduction of CaO agglomerates, the principles have been developed based on knowledge of gas-particle hydrodynamics, which are discussed below: In all the embodiments described below, the particles flow directly down the separation reactor against gravity.

[0089] The preferred approach to suppress agglomerate formation is to increase the average particle size at a constant mass flow rate. The basic rationale is that the particle number density is significantly reduced, thus reducing the particle-particle collision rate, and the momentum from particle-particle collisions is large enough that the necks of CaO created during collisions are not strong enough to break, and the colliding particles bounce off instead of sticking together. Prior art on direct separation reactors generally considers particles to be on the order of 20 μm, typically less than 100 μm. The objective of the invention disclosed herein is to increase the particle size to about 250 μm. There are three factors that reduce the degree of calcination that can be achieved with such large particles. First, the larger mass of the particles increases the terminal velocity, reducing the residence time of the particles; second, the average surface area is reduced, reducing the absorption of radiation by the particles from the hot wall; and third, in many materials with low porosity, the time it takes for the reaction front to move from the surface to the center of the particles increases with the size of the particles. One solution is to simply increase the length of the reactor to increase the residence time. However, in many cases this solution is not practical. Another solution is to increase the reactor wall temperature to increase the heat transfer rate. However, in many cases the steel of the reactor tubes cannot withstand high temperatures, as they lose strength and corrosion mechanisms accelerate. New steels have the potential to mitigate such effects.

[0090] Another solution is shown in Figure 1. Residence time can be reduced by using a counterflow configuration where friction of the gas particles against the rising gas produced in the reaction reduces the terminal velocity of the particles. In Figure 1, a direct separation reactor with counterflow is described, where the powder feed 101 is injected into the reactor system by a rotary valve 102 and enters the reactor tube 104 through an injection tube 103. The falling powder 105 is heated towards reaction temperature by a hot rising process gas stream 106, which, in the form of a plume, rises from the reaction zone 107 by gas-particle heat transfer by counterflow. The cooled gas is separated from the entrained powder by a system including a separator plate 108 and a tangential gas ejector tube 109, resulting in a cooled process gas stream 110. The powder in this gas stream is extracted by a cyclone / filter system (not shown) and reinjected into the reactor. The powder 111 heated in the reactor slowly falls against the rising gas and enters the reaction zone 107, where it is heated by radiation from the reactor walls. Heat is generated in the furnace 112, which heats the steel wall 113, and the heat flows to the gas and particles in the reactor, inducing the desired reaction. The length of the heating zone is long enough for the reaction to be completed to the desired extent. The falling hot calcined powder is collected in the reactor cone 114, forming a hot calcined powder bed 115, which is extracted from the reactor by an exhaust valve 116, which may be a system of flap valves, resulting in a calcined powder stream 117. The advantage of this configuration is that the process can achieve high thermal efficiency without relying so much on external heat exchangers, since the particles are heated by heat transfer between the falling particles and the rising hot gas. It should be noted that in many cases this approach may not seem effective, since particles of such mass and size would, in principle, be easily evacuated from the reactor. However, the wake of large particles is known to exhibit strong gas vortices behind the falling particles, which tend to cause the particles to form clusters, which minimizes friction of the gas particles, and the clusters flow down the tube against the rising gas.Furthermore, by reinjecting the entrained particles back into the reactor, the mass of particles accumulated in the reactor grows to the point where the particles organize into clusters and have sufficient mass density to break through the rising gas. At high mass flow rates, particle clustering is sufficient and the fast exchange of particles between clusters may result in a more laminar flow condition for the cluster momentum, suppressing large-scale turbulence, with the added benefit that the momentum of the particles flowing towards the wall suppresses the growth of fouling and minimizes gas-particle friction. Furthermore, it should be noted that if the particles are not injected into the heated zone of the reactor, no process gas is produced. Thus, conditions are always created where the particles must flow down the reactor. One effect of the configuration of Figure 1 is that pulsations may occur in the mass flow through the reactor, and such effects may be controlled by the reactor and cyclone / filter settings. Another advantage of the configuration of Figure 1 is that the particle flow to the bottom of the reactor is not affected by the gas flow, and the larger particles in the reactor bed do not undergo significant agglomeration as do the smaller particles, so particle conveying and transport out of the reactor is not impeded. It has been found that to inhibit such agglomeration, small amounts of steam or air, preferably at high temperature, can be injected into the bottom. CO. 2 Steam or air in the gas stream is condensed or removed during the compression process using standard processes. These gases are preferably less than 10% of the process gas stream, most preferably less than 5%. Such hot gases can also adjust the residence time of the powder, and if the gas is preferably steam or air, the reduction in partial pressure can increase the degree of calcination by reducing the equilibrium pressure of the calcination reaction. Additionally, in the case of carbonate calcination, the CO at the bottom of the reactor can be used to reduce the amount of CO released. 2 This replacement reduces the agglomeration of particles remaining in the bed at the bottom of the reactor, promotes fluidization, and reduces effects such as rat-holing.

[0091] Another advantage of the configuration of FIG. 1 is that the strength of the particle-particle bonds between the larger particles is low, resulting in less heat transfer-limiting tube surface fouling than observed with smaller particles. Experiments have shown that the vertical surfaces of the tubes are self-cleaning for both small and large particles, and that parts of the coated surface flake off at high temperatures, suggesting that the strength of the interparticle bonds is weak enough to support thick coatings, and that the thickness of the fouling is typically less than 1 mm. The thickness of the coating (measured by the temperature drop between the inner steel wall and the exposed coating surface) is found to decrease with increasing particle flux, as would be expected from the increasing shear forces caused by the high momentum of the solids that dislodge the coating. This is a feature of all configurations disclosed below. However, the thickness depends on the embodiment described herein, and it is found that the suppression of agglomeration correlates with a lower coating thickness.

[0092] It should be noted that this configuration in Figure 1 is generally applicable to the calcination of materials where large particles have little tendency to agglomerate. Longer residence times and less powder loss due to clustering in the countercurrent are generally advantages. In applications where the process is a phase change in pyroprocessing, the residence time can be increased by injecting a gas at the bottom, which can be chosen to catalyze the phase change. An example is the processing of α-spodumene to β-spodumene for the extraction of lithium, where the catalyst is water vapor.

[0093] In many cases, it is not possible to increase the particle size of the powder being fed, which makes the approach of the embodiment of Figure 1 impossible. It has been observed that when small particles are directly injected into a separate reactor, multiple effects can occur that are encountered when CaO is formed by calcination. These include increased fouling of the hot steel reactor surface, which creates resistance to radiative heat transfer from the walls to the bulk of the reactor, increased resistance to the flow of powder collected at the bottom of the reactor, and large agglomerates formed in the reactor that do not fall through the reactor at sufficient speed to reduce the degree of calcination. As mentioned above, all these effects can be attributed to the sticky nature of lime that occurs during calcination. In some cases, large granules of lime up to several mm in size are formed, in which case the agglomeration of the agglomerates leads to the formation of larger agglomerates of this size, hence the term "cascade agglomeration". In other conditions, the size of the agglomerates is smaller, for example about 100-150 μm. It is possible that such conditions can be found and the desired degree of calcination can be achieved by calcination of such agglomerates, but it is difficult to manage the occurrence of cascade agglomeration from limited agglomeration, which is undesirable for quality control.

[0094] The principle for reducing agglomeration is to minimize turbulence in the gas particle flow at all length scales, since high turbulence maximizes particle-particle and particle-wall collision frequency, and suppression of turbulence limits the formation of agglomerates. The embodiments of Figures 2 and 3 show examples where agglomeration can be controlled by minimizing turbulence. Figure 2 shows a co-current system where the process gas stream is discharged at the bottom of the reactor, while Figure 3 shows a system where the process gas stream is discharged through a central tube, which causes the gas stream to be discharged at the top of the reactor.

[0095] In FIG. 2, a direct separation reactor with co-flow is described, where the powder feed 201 is injected by a rotary valve 202 into an inlet tube 203 and enters the reactor tube 204. The falling powder 205, in a plume, is heated towards reaction temperature by radiation from the steel reactor wall 206 which heats the gas and particles, the heat being generated in an external furnace 207, which heats the steel wall. The heated powder 208 falls deep into the reactor and enters the reaction zone 209, where the radiant heat from the wall is absorbed and induces the desired reaction. As the reaction proceeds, hot process gas 210 accelerates the particles through the reactor by co-flow. The length of the heating zone is long enough for the reaction to be completed to the desired extent. The calcined powder 211 and hot process gas 212 exit from the bottom of the reactor. These gas and particle streams are separated by a reactor cone 213, a gas ejector tube 214 and a powder bed 215, which acts as an inertial separator, forcing hot process gas vapors 216 out of the reactor and depositing the powder onto the powder bed. The hot powder stream 217 is exhausted from the reactor by an exhaust valve 218, which may be a system of flap valves. The powder in this gas stream is extracted by a cyclone / filter system (not shown) and reinjected into the reactor.

[0096] In FIG. 3, a direct separation reactor with co-flow is described, where powder feed 301 is injected into injection tube 303 by rotary valve 302 and enters reactor tube 304. Falling powder 305, in the form of a plume, is deflected by deflection cap 306 and enters the reaction annulus formed by hanging central tube 307 (the suspension is not identified). Falling powder 308 is heated to reaction temperature within the annulus by radiation from steel wall 309 heated by furnace 310. Heated powder 311 falls deep into the reactor and enters reaction zone 312 where radiant heat from the wall is absorbed and induces the desired reaction. As the reaction proceeds, hot process gas 313 accelerates the particles through the reactor by co-flow. The length of the heating zone is long enough for the reaction to be completed to the desired extent within the annulus. The gas and particle streams are separated by a reactor cone 314, which forces a hot process gas stream 316 into the central tube 307, which exits the reactor through a gas ejector tube 317, where the powder is deposited in a calcined powder bed. The hot powder stream 317 exits the reactor by an exhaust valve 319, which may be a system of flap valves. The powder in the gas stream 317 is extracted by a cyclone / filter system (not shown) and reinjected into the reactor.

[0097] The essential difference between Figure 1 and Figure 3 is that in Figure 3 there is a physical barrier to separate the gas and powder flows. Note that in Figure 1 the powder tends to flow down preferably near the outer wall of the reactor, since it is known from basic principles that in that region the friction of the gas particles is lowest.

[0098] One relative advantage of the central tube in Figure 3 is that the higher velocity of the ascending gas stream allows for a smaller size cyclone at the top of the reactor to separate the fines than an inertial separator, which then reinjects the particles into the upper reactor, whereas a larger inertial separator at the bottom of the reactor is less efficient and a cyclone / filter is required to separate the fines. Another advantage is that the central tube can absorb radiation from the hot outer tubes and this tube can re-radiate that energy back into the gas particle stream, optimizing the net heat transfer rate. Another advantage is that the hot CO escaping from the top of the reactor can be efficiently removed by the central tube. 2 The flow of the central tube can be used to partially preheat the input powder stream, for example in a cyclone. This aspect is considered separately below with respect to optimizing the integration. Another advantage of the central tube is that the extraction efficiency at the bottom can be increased by adding a swirling element near the end of the tube in the annulus and a swirling element of blades near the inlet of the inner tube. Both of these elements create additional flow patterns in the gas above the cone at the bottom of the reactor, increasing the particle-gas separation efficiency in the area below the central tube. Nevertheless, the gas-particle separation at the bottom is sufficiently effective without the use of either of these options. The central tube in FIG. 3 can be perforated or composed of hanging segments. Also, blades can be used in the tube to swirl the gas so that the entrained powder can be extracted from the gas stream into the annulus by an in-line ejector. The embodiment of FIG. 3 is preferred because it provides such an option. There are also additional options to mitigate agglomeration and its associated effects. Sintering of the particle reaction surface has been described above. One such surface is the outer surface of the particle, where the reaction front develops first and where, as calcination begins, this surface begins to sinter, from which point onwards it becomes less inclined to bond the particles together. In many direct separation reactor configurations, the particles are preheated prior to injection into the reactor. Figure 4 shows an exemplary embodiment in which a preheating process can be used to partially passivate the outer particle surfaces by partially calcining and sintering the surfaces.

[0099] Those skilled in the art will appreciate that 2It will be appreciated that the temperature at which sintering begins can be reduced by reducing the partial pressure of CO. Also, those skilled in the art will appreciate that preheating of the powder can be achieved by using low CO to initiate surface sintering to a controlled extent in the preheater. 2 It will be appreciated that the temperature can be managed using gas flows. In FIG. 4, the preheat segment of the preheat / calcination / sintering system is depicted. Powder feed 401, at a temperature below the calcination temperature, as described below, is injected by rotary valve 402 into injection tube 403, which delivers the particles into a refractory-lined heat exchange reactor tube 404, resulting in a plume of injected falling powder 405. A hot steam / air stream 406, which has a high enough temperature to preheat the powder, induce a limited degree of calcination of the solids, and sinter the calcined particles, as described below, is injected into the bottom of the system using a tangential gas injection tube 407 and flows upward as a swirling gas stream 408. Heat exchange occurs between the ascending gas stream and the powder stream as they move countercurrently, and the injection conditions of the system are designed to reduce large-scale turbulence, optimizing heat transfer between the particles and the gas. The rising gas stream is exhausted to a gas exhaust 411 through a system of separator plates 409 and tangential gas ejector tubes 410. The powder in the cooled gas stream 411 is extracted by a cyclone / filter system (not shown) and re-injected into the reactor. The falling heated powder 412 forms a bed 413 in a cone 414. The hot powder exhaust 415 is exhausted from the system using an exhaust valve 416, which may be a system of flap valves. The input temperature and mass flow rate are such that the degree of sintering of the CaO material is preferably less than 10%, most preferably less than 5%, and the residence time of the powder in the bed is such that sintering of the powder in the powder stream 415 reduces the tendency of the particles to agglomerate when input into the calciner due to the stickiness of the surface layer.

[0100] The sintering of CaO on the surface was carried out by subjecting the preheated powder to high temperature CO 2The aforementioned catalytic sintering can be accelerated by transferring some of the gas into the powder, which is passivated to some extent by the retention time of the powder in the feed hopper. Alternatively, a small amount of steam can be injected into the bed of preheated precalcined particles to passivate the powder. Without being limited by theory, it is believed that sintering of CaO is accelerated by the CO in the steam. 2 occurs faster than Ca(OH) 2The reaction of the steam to form β-pyrrolidone can be suppressed by maintaining the temperature of the material at or above about 580°C. In most cases, this condition can be met since the preheating of the powder is limited to about 720°C by the available energy. A second feature of this embodiment is to inject the preheated powder into the reactor at some point below the reactor. The intention of this approach is to reduce the particle density at higher positions in the reactor and reduce the rate of agglomeration at those positions. Such an embodiment is shown in FIG. 5, which describes a direct separation reactor with counterflow similar to that of FIG. 1, where the powder feed 501 is injected by a rotary valve 502 into an injection tube system 503 and enters the reactor tube 504. The reactor tube system of this embodiment consists of three concentric tubes compared to FIG. 1, which has one tube. The tubes are of different lengths so that the powder is released into the reactor at different heights. Falling powder 505 from each such tube is heated toward reaction temperature by the hot ascending process gas stream 506 rising from the reaction zone 507 by countercurrent gas-particle heat transfer. The cooled gas is separated from the entrained powder by a system including a separator plate 508 and a tangential gas ejector tube 509, resulting in a cooled process gas stream 510. The powder in this gas stream is extracted by a cyclone / filter system (not shown) and reinjected into the reactor. The heated powder vapor 511 from each tube in the reactor accumulates and slowly falls against the rising gas, entering the reaction zone 507 where it is heated by radiation from the reactor walls, generating heat in the furnace 512 which heats the steel wall 513, which then flows to the gas and particles in the reactor to induce the desired reaction. The length of the heating zone is long enough to allow the reaction to be completed to the desired extent. The falling hot calcined powder is collected in the reactor cone 514 forming a hot calcined powder bed 515 which is extracted from the reactor by exhaust valve 516, which may be a system of flap valves, resulting in a calcined powder stream 517.

[0101] The degree of agglomeration suppression achieved by sintering is 2 Or H 2It should be noted that there may be limitations, since O binds to the surface and promotes fast surface migration of CaO at sufficiently high temperatures. This property could be exploited for the production of new materials and applications in the case of low-emission lime produced in direct separation reactors. It should be noted that limestone granules (limestone) are currently used in a wide range of high-temperature pyrolytic metallurgical processes as a slagging agent to remove silica and other impurities. These processes often used crushed limestone, but the endothermic load from calcining limestone to CaO is very high, so it is common to use limestone. Fine lime powder is not used in these processes, because in such pyroprocessing, lime particles are entrained in the gas stream, and mm-sized limestone granules are preferably used. It is interesting that direct separation reactors can produce low-emission limestone, but there are limitations to particle size as explained above. However, experimental observations indicate that the quicklime produced from these reactors can be easily rounded into granules that can be heat treated to produce granules with the necessary strength for use in such processes. The example embodiment of Figure 6 shows how such a process can produce such granules. Figure 6 shows the powder 601 and CO 2 A granulator system in which a contained gas 602 is injected into a heated rotating drum 603, which is heated by a heating element 604 to produce granules 605 at a temperature high enough that the CaO does not recarbonate. A characteristic of these granules is that they are porous in nature. Thus, a second application is the production of SO in a fixed bed. x Or CO 2 The use of such granules to capture gases such as CO2, CO2, and CO2, and their performance in such processes is enhanced by the fact that the reactivity of the CaO inside the particles is higher than lime produced by conventional processes using high drainage lime. In another example, granules of CaO material are strong, porous and permeable, and have the potential to trap H 2 O, SO x , CO 2 , Cl 2 , H 2It can be used to absorb sulfur, other gases and metal vapors without cracking. In a further example, the high surface reactivity of CaO can be utilized to produce granules of a powder mixture. For example, the granules can be composed of silicate-containing minerals such as iron ore for steel production or kaolin for alumina production, and the CaO in the granules can be used in a subsequent process to form calcium silicate by a slagging process under appropriate conditions. In the case of magnesium metal, the CaO-containing material can be dolime mixed with a reducing agent such as ferrosilicon, which when heated forms a calcium-iron silicate slag with magnesium vapor. In all such cases, the granules provide an intimate contact where the migration of CaO promotes slag formation. The above prior art recognizes that a direct separation reactor may be segmented into different zones. An example is a post-processing segment where the powder from the direct separation reactor is processed to complete the reaction process. It is understood that the residence time to complete the calcination reaction may be very long because the reaction rate slows as the reaction approaches completion. Depending on the product and application, a very high degree of calcination may be required. FIG. 7 shows an embodiment that can be used to achieve the calcination goal instead of extending the reactor length. In FIG. 7, a typical two-segment direct separation reactor is described, in which the first reactor segment is similar to that of FIG. 1, and the second reactor segment below the first reactor segment is used to complete the calcination reaction by several different designs described below, with the two segments separated by a gas block. The gas block operates with high mass flow of powder and substantially inhibits gas flow from the second segment to the first segment by gas-particle friction. Powder feed 701 is injected into the reactor tube 704 from an injection tube 703 by a rotary valve 702. The falling powder 705 is heated toward reaction temperature by a hot ascending process gas stream 706 rising from the first reaction zone segment 707 in a plume by countercurrent gas-particle heat transfer.The cooled gas is separated from the entrained powder by a system including a separator plate 708 and a tangential gas ejector tube 709, resulting in a cooled process gas stream 710. The powder in this gas stream is extracted by a cyclone / filter system (not shown) and reinjected into the reactor. The heated powder 711 in the reactor slowly falls against the rising gas and enters the reaction zone where it is heated by radiation from the reactor walls, generating heat in a furnace 712 which heats the steel wall 713, which then flows to the gas and particles in the reactor to induce the desired reaction. The length of the heating zone is sufficient for the reaction to be completed to the desired extent of the intermediate, and the calcined intermediate powder 714 falls into a cone 715 where the powder is concentrated and flows into a gas block 716 before falling into the second reactor segment 717. A gas stream 718, whose composition depends on the material and the mode of operation of this embodiment, is injected into this reactor segment, where it interacts with the powder and leaves the reactor segment as stream 719. The efficiency of the gas block is set by the pressure drop of the gas across the two reactor segments. The wall temperature of the reactor segment can be controlled by an external furnace or cooling segment 720, if required by the application. The desired reaction is completed in this segment, resulting in calcined powder 721, which is collected in the reactor cone 722 and forms a hot calcined powder bed 723, which is extracted from the reactor by an exhaust valve 724, which may be a system of flap valves, resulting in a calcined powder stream 725.

[0102] In the case of the incomplete reaction to produce CaO, the temperature of the partially calcined powder 714 is slightly above about 895° C. In one use of the embodiment of FIG. 2 The partial pressure is about 103 kPa and is reduced to about 10 kPa by injecting air or steam 718, which initiates the reaction when the powder is transferred to the second segment. Calcination can be completed by dissipating the heat in the powder or by adding additional heat as needed from the furnace 720. The same considerations apply to the production of MgO. If steam is used, the temperature must be kept above the relevant hydration temperature.

[0103] In another example of the system embodiment of Figure 7, the second segment is used to sinter the intermediate material 714. In a specific example, the intermediate is MgCO as the feed 701. 3 and gas 718 is steam, which is used to catalyze the MgO and give the MgO a surface area that is desirable for industrial applications. In the absence of steam, the specific surface area is approximately 250-350 m 2 / g, and in the presence of steam, the specific surface area is approximately 10 m 2 / g.

[0104] 7, the gas 718 may be a mixture of air or oxygen and a combustible material, which is typically a gas such as syngas that reacts by flameless combustion to generate heat for the reaction. This mode of operation is preferably facilitated by the high temperature of the powder feed 714, which exceeds the autoignition temperature of the combustible material.

[0105] Note that the second segment can be integrated directly into the first stage of the reactor by injecting air and fuel into the bottom of the single segment reactor. In this case, the concentration profile of the process gases is moderated by gas interdiffusion and increases as the gases move up the reactor due to partial pressure drop induced firing reactions.

[0106] In another example embodiment of FIG. 7, the gas 718 injected into the second segment has a component that reacts with the calcined intermediate powder 714 produced in the first segment. In this approach, the first segment is preferably operated to achieve a sufficiently high calcination degree so that the reaction of the gas with the powder in the second segment can produce the desired calcined product 725. Furthermore, the operating mode of the furnace / cooler 720 is set to establish the necessary reaction conditions, for example, heat supply for endothermic reactions and heat removal for exothermic reactions. As a specific example, if the calcined intermediate 714 is CaO from a limestone precursor 701, the input gas 718 is steam, the furnace / cooling system 720 operates in a cooling mode, and the product 725 is slaked lime Ca(OH) 2 The heat recovered at 720 can be utilized throughout the process flow to reduce the energy demands of the entire process. The same considerations apply to the conversion of MgO to Mg(OH). 2 The same applies to the generation of

[0107] A common example for the manufacture of batteries and catalytic materials is where the desired reaction is either a reduction or oxidation process of an intermediate 718 produced from a precursor 710, accomplished by using an appropriate reducing or oxidizing gas 718 and setting the temperature to induce the desired reaction for the desired product 725.

[0108] Those skilled in the art will appreciate that the principles described by the multi-segment exemplary embodiment of FIG. 7 may be applied to any firing reaction, or paired reaction, or sintering reaction, where the gases have a composition appropriate for the desired process.

[0109] The Portland cement manufacturing process takes place in several stages. Prior art describing direct separation reactors describes a process in which the initial stage of the process, namely the calcination of the cement raw powder, takes place in the direct separation reactor, and the performance of that stage may be improved by the invention described in this disclosure. The second stage takes place in a rotary kiln, where the calcined powder is injected into the kiln and heated by a flame to about 1450°C to activate the clinkerization reaction that forms the main cementitious materials belite and alite. It is noted that the thermal efficiency of a cement plant is typically about 60% or less due to high heat losses from the rotary kiln and ineffective utilization of the exothermic energy of the clinkerization reaction. The embodiment of FIG. 8 is directed to an improvement of this process. It describes how the injection of combustion gases and air / oxygen is used to increase the temperature of the powder exiting the direct separation reactor by a homogeneous combustion reaction. The application of the embodiment of FIG. 8 shows a process in a refractory lined segment that utilizes a countercurrent of rising reacting air and fuel to heat the powder to a temperature of about 1260°C or higher. In FIG. 8, a specific two-segment direct separation reactor for producing clinker from preheated cement powder is described, adopting an approach of forming clinker in the direct separation reactor segment. In this approach, the option of using a flap valve to separate gas vapors is used. Cement powder 801 preheated to about 720°C is injected into an injection tube 803 using a rotary valve 802 and fed into a reactor tube 804. The falling preheated powder 805 is in the form of a plume and is mixed with the hot rising CO2 rising from the first reaction zone segment 807 by gas-particle heat transfer by countercurrent flow. 2It is heated towards reaction temperature by process gas stream 806. The cooled gas is separated from the entrained powder by a system including a separator plate 808 and a tangential gas ejector tube 809, resulting in a cooled process gas stream 810 at approximately the same temperature as 801. The powder in this gas stream is extracted by a cyclone / filter system (not shown) and reinjected into the reactor. The heated powder 811 in the reactor slowly falls against the rising gas and enters the reaction zone where it is heated by radiation from the reactor walls. Heat is generated in the furnace 812, which heats the steel wall 813, which flows to the gas and particles in the reactor, inducing the desired reaction. The length of the heating zone is sufficient for the reaction to be completed to the intermediate desired degree, and the calcined cement powder 814 falls into a cone 815 where the powder is concentrated, fed by a flap valve 816, and falls into the second reactor segment 817. A fuel stream 818 and oxygen / air stream 819 are injected into this reactor segment where they undergo flameless combustion to heat the powder 820. The reactor wall 821 is a refractory tube. The combustion process heats the powder 822 to a temperature of about 1260° C. and marks the initiation of a clinkerization reaction to form belite. The hot particles fall into the vertical kiln segment 823 in a slowly moving bed. Here, particle-particle contact drives an exothermic clinker reaction, and the released heat raises the temperature to about 1450° C. or higher, forming alite if the residence time in the bed is about 30 minutes or less. The exotherm is completed in this segment, resulting in clinker granules. An exhaust valve 824 discharges the hot clinker granules 825 from the vertical kiln where they are cooled by air using a conventional grate cooler (not shown). Those skilled in the art will appreciate that FIG. 8 illustrates a more energy efficient process since the powder is heated by an exothermic reaction, unlike a conventional kiln process where heat losses are high.

[0110] High energy efficiency of industrial processes is an important factor. With respect to reactors, by using a direct separation reactor, the thermal energy efficiency for a given degree of firing is not affected. Heat losses are related to heat losses through the refractory skin surrounding the furnace and burner segments of the reactor. In this embodiment, the invention is extended to the consideration of the burner-furnace configuration. The important factors for heat transfer are temperature and convective heat exchange to the steel reactor walls and furnace refractory, and optimizing radiative heat transfer through the steel reactor walls. Generally, this is optimized by known techniques using high gas flow rates and gas swirl. Direct separation reactors can be operated by using a separate burner box and piping the hot flue gases to the furnace surrounding the reactor tubes in a way that gives these desirable characteristics, and the hot flue gas exhaust can be used to preheat the air for combustion. However, ducting and distribution of hot gases is undesirable. In FIG. 9, an exemplary embodiment for processing limestone shows a different approach. The fuel chosen is synthesis gas from biomass, and after combustion, CO 2 Using a capture system 2 Carbon-negative products are shown when the flow is sequestered (not shown). Generally speaking, it is desirable to closely integrate the combustor, furnace, and air recovery process to reduce the amount of air required. The embodiment of FIG. 9 shows that an array of recuperative flameless systems can be applied to reduce the flue gas volumetric flow rate. In such a system, the combustor and furnace are integrated, there is no flame, and the mixed gas flow rate is high, so the gas temperature is uniform. Regenerative flameless combustors have very high thermal efficiency, and the absence of flames minimizes NOx generation. The use of such systems in a distributed manner allows for the control of temperature along the tube, allowing for the optimization of the firing process within the tube. In the embodiment of FIG. 9, a system using a direct separation reactor is described, with a d of about 125 μm. 50The limestone feed 901, ground into powder, is processed into lime 902. The reactor system has three segments: a first powder preheater segment 903, a second powder preheater segment 904, a direct separation reactor segment 905, and a powder cooler segment 906. In the first powder preheater segment, hot CO from the limestone process is cooled to room temperature and then cooled to room temperature. 2 Stream 907 is injected into the bottom of the countercurrent heat exchange refractory lined tubes of the first powder preheater segment 903 into which ambient temperature limestone powder 901 is injected and cooled CO 2 This results in a gas stream 910 and partially heated limestone 911 which is formed into a bed. The partially heated limestone 911 from the bed is injected into the top of the heat exchange refractory lined tubes of the second powder preheat segment 904 where it is heated by a hot air stream 912 from the powder cooler segment 906 described below and preheated limestone 913 is formed into a bed. If necessary, the temperature of this air stream can be increased by a duct heater (not shown) to bring the temperature of the preheated limestone to or near the calcination start temperature of the limestone of about 930°C. The cooled air stream 914 is vented but is used to generate post combustion CO for flue gas as described below. 2 It can also be used to provide low grade heat to the capture system 915 (not shown). The preheated limestone 913 is injected into the direct separation reactor segment 905, shown here as a countercurrent system in FIG. 1, and the treated CO 2 is discharged at about the same rate as the preheated limestone. 2 A pure stream of biomass 907 and hot lime powder 916 are obtained. The direct separation reactor is heated by the combustion of a hot syngas stream 917 formed from biomass 918 and air 919 in a gasifier 920. In the gasifier, the syngas and ash 921 are separated. Tars produced in the gasification process can be reinjected into the hot syngas steam. The steel tubes 922 of the direct separation reactor segment 903 are heated by the combustion of hot syngas by a number of regenerative flame combustion systems, one of the steel tubes 922 injects air 923 preheated by hot flue gas from the combustor in a heat exchanger 924 and cools the flue gas steam 925 to achieve a thermally efficient combustion process. CO from that gas stream is then removed. 2 is post-combustion CO2 is injected into the capture system 915 where CO 2 926 is extracted and mixed directly with the separated gas vapor 910 to produce CO for compression and liquefaction. 2 Vapor 927 is obtained (not shown).

[0111] CO from fossil fuel combustion gases 2 Emissions are CO from the calcination product 2 It is a major contributor to emissions intensity. For lime and cement, combustion emissions are about 35% of the total emissions when using typical solid fossil fuels like coal. One approach to reduce combustion emissions is to use biofuels and use them in combination with a direct separation reactor. Biofuels are solid fuels, commonly called biomass, that can be gasified to syngas using known techniques and can be used in the configuration of Figure 9. Integrated Gasification Process The gasification process is carried out using known techniques where biomass is heated in steam / air to release combustible volatiles, the ash, including fly ash, with its carbon residue is separated and burned, and an indirect heating process provides the heat for volatilization. The hot volatiles are burned in a flameless combustor using preheated air. In this process, the gas may contain not only syngas but also tar precursors. This is because the tar precursors are burned. This means that the gas is kept above the tar condensation process, eliminating the need for costly processes to remove the tar precursors, and the fuel is not only preheated but also has a high LHV for combustion. Fly ash is removed from the gas stream to minimize the formation of silica glassy deposits on the steel walls of the furnace. The post-combustion capture process of Figure 9 can use either amines, bicarbonates, or hydrotalcites.

[0112] The above-mentioned embodiments and those illustrated by the examples in Figures 1-9 relate to reactors based on a single tube. Scaling up the process by increasing the diameter of the reactor is limited by the absorption of heat from the hot walls by the particles and the process gas, and the mass flow rate is limited by the heat transfer capacity of the walls and the involvement of particles in the process gas which affects the residence time of the particles in the reactor tube. Typically, the mass flow rate through a reactor with a diameter of about 2 m ranges from 5 to 10 tonnes / hour. The height of the reactor depends on the reaction rate of the process and the heat transfer rate from the walls, and is usually 10 to 30 m. Scaling up the process therefore means increasing the number of tubes. However, there are tricks in the design of the array of reactor tubes, which are described herein. Figure 10 is an exemplary embodiment of a scaled up system, where the tubes, shown as four in the embodiment, are incorporated into a furnace, with a minimal amount of refractory between the tubes so that any tube can be stopped with minimal impact on the adjacent tubes. The temperature of the non-operating tubes is low enough that there is no risk of distortion of the tubes, and the set points of the operating tubes can be adjusted to maintain product calcination and other process variables. This condition is achieved within the module, where every tube is operable, and the process flows in each tube can be varied with acceptable known thermal coupling between the tubes. In the embodiment of FIG. 10, the refractory can be constructed from stacked cast blocks that are provided for integration into the input fuel gas and flue gas distribution systems of the module, and a flameless combustor is shown. The cast blocks are designed to minimize the mass of the refractory, minimizing construction and replacement costs. In this embodiment, each tube has its own preheat and aftertreatment system to minimize the transport of hot gases and powders. The embodiment of FIG. 10 is a schematic diagram of a reactor module 102 with four direct separation reactors 1, 2, 3, 4 integrated into the refractory 103. The system is based on the concept that the transport of cold powders and cold gas vapors is a known technology, and by having these process flows at the lowest temperatures, costs and challenges can be reduced. In this embodiment, ambient powder 104, a gaseous fuel source 105, and ambient air 106 are input.The direct separation reactor is based on the embodiment of Figure 1 and the combustor of Figure 9. Thus, the input powder is transported by cold powder conveyor 107 from hopper 104 through separate lines to each reactor to each stage 1 preheater PH1-1,2,3,4 and from each direct separation reactor segment DS-1,2,3,4 to process CO. 2 108 cooling, central CO 2 The flue gas 110 from the reactor combustor, after being recuperated with the incoming air stream, is directed to a post-combustion capture plant 111 to capture and separate the combustion CO 2 Stream 112 (which is then compressed), and flue gas. For the production of cement powder, the hot powder stream from each reactor can be transferred to a rotary kiln by an air slide as described in the embodiment of FIG. 11 below.

[0113] Further scale-up can be achieved using several modules such as those shown in Figure 10. The advantage of this approach is that tubes that may become inoperable can be replaced while others continue to operate, and such tubes can be commissioned and their operation optimized at the preheat, firing and cooling stages to deliver a fired product that meets specifications.

[0114] Ancillary equipment used for preheating and post-processing of powders and gas streams may benefit from scale-up by scaling up to a single module. Although such an approach requires hot gas and powder distribution, there are many approaches that can be used to achieve such scaling benefits. Such a system is shown in Figure 11, where a four tube module has a single preheater stack; preheated powder is evenly distributed to the tubes using a 1:4 L-valve distribution system with controls to feed any number of tubes; the calcined powder stream is collected using a 4:1 heated air slide system with similar controls; and hot CO 2 The stream is then pumped to a single CO 2Such heat recovery systems are known to scale up from the use of suspension cyclones in cement plants. In this embodiment, the combined CO 2 The heat in the flow is used to preheat the powder in the first stage of the cyclone stack. For cement production, a hot air slide feeds the hot calcined powder to a single rotary kiln (not shown). The embodiment of FIG. 11 is a schematic of a system using a reactor module 111 of four direct separation reactors 1, 2, 3, 4 integrated in refractory 113. This system is based on the concept that the transportation of hot powder and hot gas vapors is a known technology and the high cost and challenges of these elements are offset by using large preheaters and coolers rather than the embodiment of FIG. 10 where each reactor requires a separate system. In this embodiment, preheated powder 114, a gaseous fuel source 115, and ambient air 116 are input. The direct separation reactors are based on the embodiment of FIG. 1 and the combustor of FIG. 9. For hot powder, the means of controlling the flow rate to each tube is to use an L-valve fluidized bed 117 fluidized with hot air 118, and the heat losses in each conveyor tube are minimized by the refractory tubes. The preheated powder conveyor system for each tube is pneumatically inclined to avoid salting out. Each reactor, DS1, DS2, DS3, DS4, is a high-temperature process CO 2 This produces a high temperature CO 2 Stream 119 and hot flue stream 120 are aggregated and are conveyed through refractory coated pipes (not shown) to a central preheater for the powder. Calcined powder streams Cal1, Cal2, Cal3, Cal4 from each tube are conveyed by a system of tubes, in one example conveyance being achieved by a refractory surrounded inclined hot air slide 121. The agglomerated hot calcined material 122 is typically injected into a powder cooling system (not shown) or into a rotary kiln system in the case of cement production.

[0115] Although the present invention has been described with reference to specific examples, it will be understood by those skilled in the art that the present invention can be embodied in many other forms while still remaining consistent with the broad principles and spirit of the invention described herein.

[0116] The present invention and the preferred embodiments described specifically include at least one feature that has industrial applicability.

Claims

1. 1. A method for calcining a powder material using a system for calcining a powder material, the system comprising a plurality of vertical reactor tubes, a gas ejector tube, and an external heating system, comprising: The powdered material is injected into the reactor tube through the injection tube at one or more depths; The powder injected from the injection tube and falling into the heating zone while passing through the reactor tube is heated by radiation from the external heating wall of the reactor tube by an external heating system; The powder material comprises a compound or mineral that releases a gas when heated, and the particle volume distribution of the powder material is limited to 90% having a diameter less than 250 μm and 10% having a diameter greater than 0.1 μm; The average velocity of the falling powder particles while passing through the reactor tubes is less than 1.0 m / s, and the powder material flux in each tube is between 0.5 and 1 kg m －２ ・s －１ and the length of the heating zone is in the range of 10 to 35 m.

2. 2. The method of claim 1, wherein the gas is at least one selected from the group of carbon dioxide, steam, an acid gas such as hydrogen chloride, and an alkaline gas such as ammonia.

3. The method of claim 2 , wherein the mineral is limestone.

4. The method of claim 2 , wherein the mineral is dolomite.

5. 5. The method according to claim 3 or 4, wherein the compound comprises silica and clay and the powder material is raw cement flour for the production of Portland cement.

6. 2. The method of claim 1, wherein the evolved gas flows upwards in the tube against the flow of the calcined powder, the gas being exhausted at the top of the system.

7. 2. The method of claim 1, wherein the released gases and the gases introduced into the system flow downwardly within the reactor tube along with the flow of calcined powder, and the gases are exhausted at the bottom of the system.

8. 2. The method according to claim 1, wherein an inner tube is disposed in each tube, the powdered material flows downwards in the reaction ring together with the discharged gas, and at the bottom of the reactor, the gas flow is reversed to flow upwards through the inner tube, and the discharged gas and the gas introduced into the system are discharged at the top of the system.

9. A method according to any one of claims 6 to 8, wherein powdered material entrained in the exhausted gas is separated and reinjected into the system.

10. A method according to any one of claims 6 to 9, wherein the injected powder is preheated in a gas-powder preheater system before being injected into the system.

11. 11. The method of claim 10, wherein the gas-powder preheater system is one or more refractory heating tubes through which the cold powder material falls through and is heated by the hot ascending gas, and the average velocity of the powder while passing through the preheat tubes is 0.5 m / sec or less.

12. A method according to any one of claims 6 to 9, wherein the powder discharged from the bottom of the system is cooled in a gas-powder cooling system.

13. 13. The method of claim 12, wherein the gas-powder cooling system is one or more refractory cooling tubes through which the hot powder material falls through a cold ascending gas, and the average velocity of the powder while passing through the cooling tubes is 0.5 m / sec or less.

14. The method of claim 1 , wherein the external heating system for externally heating the tube walls is an integrated combustor and furnace system that allows for control of the temperature profile below the heating zone of the system.

15. 15. The method of claim 14, wherein the external heating system is a flameless combustion system that allows for control of the temperature profile below the heating zone of the system.

16. 16. The method of claim 14 or 15, wherein the fuel of the external heating system is at least one gas selected from the group of natural gas, synthesis gas, town gas, producer gas, and hydrogen, and the combustion gas is air, oxygen, or a mixture thereof heated from a flue gas of the external heating system.

17. CO in flue gas ２ However, after regeneration combustion, ２ 17. The method of any one of claims 14 to 16, wherein the extraction is performed using a capture system, the system being at least one selected from the group consisting of an amine sorbent system, a bicarbonate sorbent system, and a calcium looping system.

18. 2. The method of claim 1, wherein the external heating system is an electric furnace and power is generated from a hot gas stream or extracted from a grid within a production plant of which the system is a part, and configured to enable control of a temperature profile below a heating zone of the system.

19. 20. The method of claim 1, wherein the external heating system is a combination of any one of the external heating systems described in claims 14, 15 and 18, which may be applied to different segments of each tube or to different tubes, and operation of the system allows the use of variable combinations of such external heating systems while maintaining a continuous production of sintered material.

20. 10. The method of claim 1, wherein the powdered material is injected into the reactor tube at several depths.

21. 2. The method of claim 1, wherein each tube is divided into a plurality of segments mounted in series, and gas released or introduced at each segment is extracted from that segment using a gas block between the segments.

22. 22. The method of claim 21, wherein the partial pressure of the gas released during firing in the upper segment can be reduced in the lower segment such that the reaction proceeds further by partial pressure drop to achieve a new equilibrium at a lower partial pressure, which includes a drop in the wall temperature of the lower segment such that thermal energy stored in the partially fired powder from the upper segment is used for firing.

23. 22. The method according to claim 21, wherein the wall temperature of each segment is increased in each segment starting from the top segment so that the gas released from each segment is a specific gas of a desired purity, and other gases may be added to each segment to promote catalytic reaction of the reaction step and / or sintering of materials during the reaction step.

24. 24. The method of claim 23, wherein the system produces sintered MgO for the refractory block from magnesite.

25. The system converts limestone or magnesite into Ca(OH) ２ , or Mg(OH) ２ 24. The method of claim 23, wherein

26. The method of claim 23 , wherein the system controls the oxidation state of the battery precursor.

27. 2. The method according to claim 1, wherein each tube is divided into several segments, the gas discharged or introduced in each segment is extracted from that segment using a gas block between the segments, and a hot gas flow is introduced into the segment to increase the thermal energy of the gas and particles in that segment to augment the thermal energy provided by the external heating.

28. 28. The method of claim 27, wherein the gas flow includes a combustible fuel and oxygen or air for combustion to induce combustion in the segment and increase the thermal energy of the gases and particles in the segment to augment the thermal energy provided by external heating in the segment or other segments.

29. 28. The method of claim 27, wherein the temperature increase from the combustion is sufficient to induce particle-particle or interparticle reactions typical of subsequent torrefaction or clinkering reactions in a powder bed formed at the bottom of the segment, and the energy released from the exothermic reaction is capable of maintaining or increasing the temperature of the powder bed, such that the induced reactions are fully completed during the residence time in the powder bed.

30. 11. The method of claim 10, wherein the preheat temperature of the gas-powder preheater system is in the range of 650-800°C and the partial pressure of the gas released during calcination is less than 15 kPa, so that the powder material is partially calcined and then sintered to sufficiently reduce the surface energy of the particles, thereby reducing the tendency of the particles to subsequently bond and agglomerate.

31. The material is limestone, the calcined material or a mixture of the calcined material and other minerals is introduced into a post-processing system to produce granules of the material, the granules are formed by agitating the powder, the gas environment includes carbon dioxide, and the temperature of the granulator system is adjusted to a temperature below that of the limestone and CO ２ The method according to claim 1, wherein the temperature is in the range of 650 to 800° C. at which recombination with the metal is suppressed.

32. 2. The method of claim 1, wherein the material is first calcined in a first segment using a steel reactor wall to supply heat to the system, and the gases released or introduced in each segment are extracted from that segment using a gas block between the first segment and the lower segment, so that a second gas flow of a different gas is injected into the second segment and the heat transfer through the reactor wall of the second segment is controlled so that the calcined powder from the first segment reacts with the gas to produce new material compounds.

33. The powder material is limestone CaCO ３ , or dolomite CaCO ３ MgCO ３ and the calcination product from the first segment is lime CaO or dolomite CaO.MgO, and the exhaust gas is CO ２ and the gas injected into the second segment is steam H ２ 33. The method of claim 32, wherein the temperature is controlled by removing heat through the wall as slaked lime is discharged from the second segment, and the diameter of the tubes in the system is selected to balance heat transfer and reaction rate with residence time at the minimum segment length.

34. The slaked lime or dry lime product is CO in the ambient air. ２ It has high reactivity with CaCO ３ Or MgCO ３ CaCO ３ and this product is converted to CO from ambient air in a circulation system. ２ This product is then reintroduced into the system to remove CO2 from the combustion ２ 34. The method of claim 33, wherein when involving capture of carbon dioxide, the system produces carbon negative emissions products.

35. 10. The method of claim 1, wherein the reactor tube is vibrated to remove buildup of solid material adhering to the walls of the system.

36. 10. The method of claim 1, wherein the heat from the external heating system to each tube is isolated by a refractory wall so that the plant can operate efficiently with any number of tubes through the use of refractory materials and energy distribution including gas and radiation, whereby the exposure of any tube to radiation and convective transfer of heat is controlled such that the temperature profile is controlled within a desired range related to thermal stresses in the metal tubes and energy consumption by the system.

37. 37. The method of claim 36, wherein the preheater segment and / or the cooler segment require distribution of preheated material from a central preheater to each tube, the distribution being achieved by at least one of the group consisting of L-valves, an assembly of L-valves designed to provide controlled distribution of powder to each tube, an agglomeration system that collects hot calcined material from each tube to a central cooling system, and a central downstream processing system such as a kiln, and the agglomeration is achieved by a system of gas slides where the flow of hot calcined powder is controlled to provide a continuous flow of material.

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