JP5820669B2 - Switchable chemical loop combustor - Google Patents

Description

  The present invention relates to a chemical loop combustor.

  A chemical loop combustion method in which an oxidation reaction in which fluid metal particles react with an oxidant to form metal oxide particles and a reduction reaction in which the metal oxide particles undergo reduction by a reducing agent continuously proceed. Is known. It is also described in Patent Document 1 and the like that chemical loop combustion is actually performed, and reaction heat generated by the oxidation reaction of metal particles at that time is collected and used for industrial purposes. Moreover, the apparatus for implementing chemical loop combustion is also described in the nonpatent literature 1, the nonpatent literature 2, etc., for example.

  In chemical loop combustion, instead of burning the fuel directly with air, the combustion reaction is divided into two parts: "oxidation of metal particles" and "reduction of oxidized metal particles", so that fuel (reducing agent) and air ( Pure oxygen is exchanged using metal particles as a medium without direct contact of (oxidant). As described in Non-Patent Document 1, a conventional chemical loop combustion apparatus has a configuration in which an oxidation tower and a reduction tower are provided separately (referred to as an external circulation type), or a configuration in which a reduction tower is disposed inside the oxidation tower (internal In any form, the oxidation tower and the reduction tower are connected by circulation of physical metal particles.

In chemical loop combustion, the temperature generated by the oxidation reaction is usually about 800 to 1200 ° C., and the exhaust gas, which is mainly N ₂ , has a relatively low temperature, so that thermal NOx is hardly generated. Further, in the reduction reaction system, only oxygen supplied from hydrocarbons and metal oxides as fuel exists, and therefore, exhaust gas components are substantially only CO ₂ and H ₂ O. Therefore, if the exhaust gas discharged is cooled to remove H ₂ O, substantially pure CO ₂ can be easily collected.

JP 2000-337168 A

Use of NiO / NiAl2O4 Particles in a 10 kW Chemical-Looping Combustor Marcus Johansson, Tobias Mattisson, and Anders Lyngfelt Ind. Eng. Chem. Res. 2006, 45, 5911 5919 (external circulation type) Experimental results of chemical-looping combustion with NiO / NiAl2O4 particle circulation at 1200 degrees C Ishida M, Yamamoto M, Ohba T ENERGY CONVERSION AND MANAGEMENT 2002, 43,9-12,1469-1478 (internal circulation)

  As described above, there are two types of chemical loop combustion devices currently under investigation, an external circulation type and an internal circulation type, both of which circulate metal particles as a medium between an oxidation tower and a reduction tower. It carries oxygen and continues the reaction. However, in order to circulate the metal particles, in the case of the external circulation type, a pipe connecting the oxidation tower and the reduction tower is required, and the surface area increases and the heat dissipation loss increases. Further, in the internal circulation type, the pipe connecting the oxidation tower and the reduction tower can be omitted, so that the apparatus can be miniaturized. However, the metal inside the oxidation tower exposed to a temperature of about 800 to 1200 ° C. for a long time is provided. It is necessary to install a complex-shaped solid-gas separation device for separating particles and gas components, which is difficult in terms of durability. Furthermore, in any method, it is necessary to circulate the particles continuously, but it is difficult to circulate high temperature particles stably, and it is difficult to grasp the amount accurately. It has become.

  The present invention has been made in view of the above circumstances, and by using only one reaction tower, the reaction tower has both a function as an oxidation tower and a function as a reduction tower. To provide a new type of chemical loop combustor, that is, a switchable chemical loop combustor, that eliminates the need for circulating metal as a contributing medium, thereby simplifying the overall configuration and improving durability. Let it be an issue.

  The switchable chemical loop combustor according to the present invention basically has an oxidation reaction stage in which a metal as a medium that contributes to a redox reaction (hereinafter referred to as “metal as a medium”) reacts with an oxidant to become a metal oxide. And a chemical loop combustor for performing chemical loop combustion in which the metal oxide is repeatedly advanced through a reduction reaction stage in which the metal oxide is reduced by a reducing agent, the reaction tower containing the metal as the medium, It is characterized by comprising at least gas supply means for alternately supplying an oxidizing agent and a reducing agent into the reaction tower and exhaust gas exhaust means for exhausting exhaust gas from the reaction tower.

The switchable chemical loop combustor includes only one reaction tower, and the metal as the medium in the reaction tower is an oxidation reaction stage in which the gas supply means supplies an oxidant into the reaction tower. It reacts with the supplied oxidant to become metal oxide, and generates reaction heat. The high temperature N ₂ rich exhaust gas after the reaction is exhausted out of the reaction tower by exhaust gas exhaust means. In the next stage, that is, the reduction reaction stage in which the gas supply means supplies the reducing agent instead of the oxidizing agent into the column, the metal oxide in the reaction column is reduced by the reducing agent. The CO ₂ rich exhaust gas after the reaction is exhausted outside the reaction tower by the exhaust gas exhausting means. In the next stage, the gas supply means again supplies the oxidizing agent into the reaction tower, and the inside of the reaction tower becomes an oxidation reaction stage. Hereinafter, the reduction reaction stage and the oxidation reaction stage are repeated.

  As described above, the switchable chemical loop combustor according to the present invention can continuously perform chemical loop combustion only by providing one reaction tower. In addition, unlike the conventional chemical loop combustor provided with an oxidation tower and a reduction tower separately, there is no circulation between the oxidation tower and the reduction tower of metal particles, so exhaust gas and metal particles or oxidized metal It is not necessary to provide a solid-gas separation apparatus for separating particles from the reaction tower. Therefore, the configuration of the combustor can be simplified and the durability is improved. In addition, device design is facilitated.

  In one aspect of the switchable chemical loop combustor according to the present invention, the metal as the medium is a particulate metal or an oxide of the particulate metal that can flow in the reaction tower. Further, in another aspect of the switchable chemical loop combustor according to the present invention, the metal as the medium is a honeycomb-like structure fixed to the reaction tower, or a honeycomb-shaped carrier fixed to the reaction tower. It is a particulate metal or an oxide of the particulate metal supported on the surface.

  In the former aspect, the particulate metal as the metal or the oxide of the particulate metal can flow in the reaction tower during the oxidation or reduction reaction, so that the entire metal as the medium In contrast, oxidation and reduction proceed uniformly. In the latter embodiment, the metal as the medium is fixed in the reaction tower and does not scatter to the outside as in the case of metal particles. Furthermore, whether the metal as the medium is a honeycomb-like structure or a particulate metal supported on a honeycomb-shaped carrier or an oxide of the particulate metal, the gas flow is The flow is in a uniform direction, and the reaction is obtained in a flow with little back-mixing.

  In the present invention, “honeycomb shape” is a general term for a state in which a plurality of communication holes having a predetermined length are arranged in the same direction without gaps, and the cross-sectional shape of the communication holes is a regular hexagon. Is preferable from the viewpoint of strength, but is not limited thereto. As described above, the metal itself as the medium may form a honeycomb-like structure, and a honeycomb-like member made of ceramics or the like is used as a carrier, and the surface of the carrier is sintered. By such means, the particulate metal as the medium or the oxide of the particulate metal may be fixed.

  In the switchable chemical loop combustor according to the present invention, in an embodiment in which particulate metal that can flow in the reaction tower or an oxide of the particulate metal is used as the metal as the medium, It is preferable to further include an inner cylinder capable of circulating and moving the particulate metal as the medium as the medium or an oxide of the particulate metal and a nozzle for ejecting gas into the inner cylinder. It is.

  In this aspect, the metal (particulate metal or the oxide of the particulate metal) as the medium moves in the inner cylinder from the lower part toward the upper part, and as a result, in the reaction tower, the metal The entire metal as the medium can be reliably circulated, and the oxidation reaction and reduction reaction of the metal as the medium proceed smoothly.

  In a preferred embodiment of the switchable chemical loop combustor according to the present invention, a filter made of a heat-resistant material is provided at the exhaust gas outlet of the reaction tower. More preferably, a filter made of a heat-resistant material in a form capable of capturing fine particles having a diameter of about several μm that cannot be captured by a cyclone is provided.

  In this type of switchable chemical loop combustor, it becomes possible for the filter made of the heat-resistant material to capture the solid particles that are about to be ejected outside the system of the apparatus, and the pipes constituting the exhaust gas exhaust means are clogged. The possibility of occurring can be effectively reduced. When the metal as the medium is a particulate metal that can flow in the reaction tower or an oxide of the particulate metal, they are likely to be scattered to the outside. The vessel is particularly effective because it can reliably catch the scattered particles.

  In the switchable chemical loop combustor having the above-mentioned heat-resistant material filter, more preferably, a plurality of heat-resistant material filters are provided, and the passage direction of the exhaust gas passing therethrough can be changed alternately. Gas flow path changing means is further provided. In this aspect, the filter made of each heat-resistant material can be backwashed, and the effect as a filter can be maintained for a long time.

  In a preferred embodiment of the switchable chemical loop combustor according to the present invention, a preheating burner for preheating the metal as the medium in the reaction tower is provided. By providing the preheating burner, the metal as the medium at the start of operation can be heated by the burner, and the oxidation or reduction reaction easily proceeds.

  In the switchable chemical loop combustor according to the present invention, the heat generated by the oxidation reaction is taken out of the system by exchanging heat with the heated fluid. Heat exchange with the fluid to be heated may be performed in each exhaust system described above, may be performed inside the reaction tower, or may be performed in both of them. In one aspect, the switchable chemical loop combustor according to the present invention includes heat exchange means having a heat transfer tube through which a fluid to be heated flows in the reaction tower.

In the switchable chemical loop combustor of this form, heat generated by the oxidation reaction of the metal as the medium is exchanged with the heated fluid flowing in the heat transfer tube in the reaction tower. Therefore, the temperature of the N ₂ rich exhaust gas discharged from the reaction tower does not increase greatly, and the average temperature of the gas passing through the reaction tower also decreases. As a result, the superficial velocity can be suppressed, so that the cross-sectional area of the reaction tower can be reduced.As a result, the switchable chemical loop combustor can be miniaturized, the surface area per combustion amount can be reduced, and heat dissipation can be reduced. Loss can be reduced. Therefore, the switchable chemical loop combustor according to the present invention can be used as a heat source for an on-site boiler, an industrial furnace, or the like.

  In a preferred aspect of the above switched chemical loop combustor, the heat exchange means is installed at a position away from the upper surface of the metal as the medium accommodated in the reaction tower. In the embodiment including the preheating burner described above, in an aspect using particulate metal or an oxide of the particulate metal as the metal as the medium, the upper surface of the metal as the medium and the heat exchange means The preheating burner is provided on the wall surface of the reaction tower in between. In this aspect, a normal air combustion burner can be used as the preheating burner, and the metal as the medium can be directly heated by the combustion heat. At the same time, the combustion exhaust gas from the preheating burner can also heat the heat exchanging means, and the heat can be used effectively. Further, in this embodiment, since the preheating burner is not installed in the metal particle reservoir, maintenance of various devices related to the preheating burner is facilitated. Further, the heated metal as the medium circulates in the reaction tower, so that the entire reaction tower is also heated. In addition, when an air combustion burner is used as the preheating burner, the air supply port of the burner can be used as an inlet for secondary air (air that unburns the secondary combustion).

  When the metal as the medium is a honeycomb structure fixed to the reaction tower, or a particulate metal or oxide of the metal supported on a honeycomb-shaped carrier fixed to the reaction tower In this case, the preheating burner is preferably arranged in a region below the honeycomb-shaped member in the reaction tower, thereby improving the preheating efficiency of the honeycomb-shaped member.

  In one aspect of the switchable chemical loop combustor according to the present invention, an inert gas is supplied into the reaction tower as a purge gas between the oxidation reaction stage and the reduction reaction stage and between the reduction reaction stage and the oxidation reaction stage. A purge gas supply means is further provided.

  In the switchable chemical loop combustor having the above configuration, an inert gas is supplied into the reaction tower between the oxidation reaction stage and the reduction reaction stage and between the reduction reaction stage and the oxidation reaction stage. Therefore, it is possible to reliably avoid the mixing of the oxidizing agent and the reducing agent in the reaction tower when switching from the oxidation reaction stage to the reduction reaction stage and when switching from the reduction reaction stage to the oxidation reaction stage. . Thereby, it is possible to prevent the oxidant and the reducing agent from coming into direct contact with each other in the reaction tower to prevent combustion, and the combustion efficiency of chemical loop combustion is improved.

In the switchable chemical loop combustor according to the present invention, the reaction tower and the exhaust gas exhaust means may be connected by a single exhaust gas exhaust pipe. However, in this embodiment, it is not easy to separate and recover N ₂ rich exhaust gas generated in the oxidation reaction stage, exhaust gas including purge gas generated in the purge gas supply stage, and CO ₂ rich exhaust gas generated in the reduction reaction stage.

Thus, in a preferred form of the switched Chemical looping combustion apparatus according to the present invention, N ₂ said flue gas exhaust means three exhaust system separated, i.e., exhausting the N ₂ rich flue gas generated in the oxidation reaction stage in the reaction column An exhaust system, a CO ₂ exhaust system for exhausting CO ₂ rich exhaust gas generated in the reduction reaction stage in the reaction tower, and a purge gas for exhausting exhaust gas including purge gas generated when purge gas is supplied into the reaction tower It is characterized by comprising three exhaust systems with the exhaust system. Each exhaust system is provided with a shut-off valve. When the shut-off valve provided in any one of the exhaust systems is “open”, the shut-off valves provided in the other two exhaust systems are “closed”. Is controlled to open and close. In the switching type chemical loop combustor having the above-described configuration, the exhaust gas composed of different components generated at each stage can be reliably separated and recovered.

  In a preferred embodiment of the switchable chemical loop combustor according to the present invention, the gas supply means includes an oxidant supply system for supplying an oxidant into the reaction tower and a reductant supply for supplying a reductant into the reaction tower. The purge gas supply means includes a purge gas supply system for supplying purge gas into the reaction tower. Each supply system is provided with a shutoff valve. When the shutoff valve provided in any one of the supply systems is “open”, the shutoff valves provided in the other two supply systems are “closed”. Is controlled to open and close. Also. Each supply system supplies an oxidizing agent, a reducing agent, and a purge gas into the reaction tower through each supply pipe. In this embodiment, the oxidizing agent, the purge gas when used, and the reducing agent when supplied to the reaction tower can be reliably separated without being mixed with each other. Thereby, combustion efficiency improves.

In a preferred embodiment of the switchable chemical loop combustor according to the present invention, the switchable chemical loop combustor further includes a piping system for returning the CO ₂ rich exhaust gas generated in the reduction reaction stage to the reducing agent supply system. In the chemical loop combustion, the supply amount of the reducing agent is smaller than the supply amount of the oxidant, so that the metal as the medium can flow in the reaction tower, or the oxidation of the particulate metal. If it is a product, it may not be fully fluidized. In the switchable chemical loop combustor of the above form, by recirculating CO ₂ and H ₂ O contained in the CO ₂ rich exhaust gas to the reducing agent supply system, the flow rate of the gas introduced into the reaction tower is increased, and the particulate state The flow state of the metal or the oxide of the particulate metal can be improved. Further, the recirculated water vapor promotes the reduction reaction by the reducing agent. Furthermore, by adjusting the recirculation amount of the CO ₂ rich exhaust gas, it is possible to adjust the fluidization state without changing the input amount of the reducing agent.

In a preferred form of the switchable chemical loop combustor according to the present invention, the switchable chemical loop combustor further includes a piping system that returns N ₂ gas contained in the N ₂ rich exhaust gas generated in the oxidation reaction stage to the oxidant supply system. In the switched chemical loop combustor of the above-described form, even when it is desired to reduce the supplied oxidant flow rate, the apparent flow rate to the reaction tower can be increased by recirculating the N ₂ rich exhaust gas. Therefore, even if the amount of oxidant input from the outside is small, the flow rate of the input gas to the reaction tower can be arbitrarily changed.

In a preferred form of the switched Chemical looping combustion apparatus according to the present invention further comprises a piping system for supplying the CO ₂ gas contained in the N ₂ gas and CO ₂ rich exhaust gas contained in the N ₂ rich flue gas to said purge gas supply means. The exhaust gas generated in the oxidation reaction stage and the reduction reaction stage in the reaction tower contains high-concentration CO ₂ gas or N ₂ gas as an inert gas. In the above-described switched chemical loop combustor, the inert gas is inactive. Since the gas can be used as the purge gas and the purge gas can be self-supplied, the operation cost can be reduced.

In the present invention, air, oxygen-rich air, low nitrogen air, or the like can be used as the oxidizing agent. As the reducing agent, natural gas, petroleum, coal, hydrogen, carbon monoxide, by-product gas and the like can be used. Further, as can be seen from the above description, the metal as the medium may be a metal having the ability to react with an oxidizing agent to become a metal oxide, and not only the metal itself but also the ability to oxidize. The metal oxide is also included. Examples of the metal as the medium include Ni, Cu, Co, Fe, and oxides thereof. Taking Fe as an example, the oxides FeO and Fe ₃ O ₄ are still included in the “metal as a medium” in the present invention because they still have the ability to become oxides.

Therefore, as an aspect of the oxidation-reduction, for example, when the metal as the medium is Fe, oxidation at any stage when the oxidation proceeds stepwise as Fe → FeO → Fe ₃ O ₄ → Fe ₂ O ₃ The reaction is also included in the oxidation reaction stage referred to in the present invention, and the reduction reaction at any stage when the reduction proceeds stepwise as in Fe ₂ O ₃ → Fe ₃ O ₄ → FeO → Fe is also referred to in the invention. Included in the reduction reaction stage.

  ADVANTAGE OF THE INVENTION According to this invention, the switchable chemical loop combustor of the new form which improved durability while miniaturizing and simplifying the whole structure is provided.

The figure shown with the piping system which attaches the 1st form of the switchable chemical loop combustor by this invention. The figure shown with the piping system which attaches the 2nd form of the switching type chemical loop combustor by this invention. The figure shown with the piping system which attaches the 3rd form of the switching type chemical loop combustor by this invention. The figure shown with the piping system which attaches the 4th form of the switching type chemical loop combustor by this invention.

  Hereinafter, several forms of the switchable chemical loop combustor according to the present invention will be described with reference to the drawings.

[First embodiment]
FIG. 1 shows a switching chemical loop combustor according to the present invention together with a piping system to which a first embodiment is attached. In the first form, a particulate metal that can flow in a reaction tower or an oxide of the particulate metal (hereinafter simply referred to as a metal particle) is used as a metal that contributes to the oxidation-reduction reaction. There is a form having an inner cylinder 5.

  The illustrated switchable chemical loop combustion apparatus A includes one reaction tower 1. The reaction tower 1 is made of a heat-resistant material such as a laminate of steel plates and refractory bricks. The reaction tower 1 is preferably a cylindrical body, and in this example, the upper end is open and the lower end side is closed by a bottom plate 3. A porous dispersion plate 4 made of a heat-resistant material is installed at a position slightly above the bottom plate 3 of the reaction tower 1. Although not shown in the drawings, the peripheral wall of the reaction tower 1 is provided with appropriate preheating means such as an electric heater for preheating the inside of the reaction tower to a temperature close to the temperature at which the metal particles start the oxidation reaction.

  An inner cylinder 5 made of a heat-resistant material such as stainless steel is accommodated in the reaction tower 1 so as to have a central axis common to the reaction tower 1. The inner cylinder 5 is fixed in the reaction tower 1 by an appropriate fastener 7 so that a gap 6 is formed between the lower end of the inner cylinder 5 and the dispersion plate 4. A nozzle 8 is attached through the bottom plate 3 and the dispersion plate 4, and the tip of the nozzle 8 is open to the inside on the lower end side of the fixed inner cylinder 5. Further, a gas supply pipe 9 is attached to the space between the bottom plate 3 and the dispersion plate 4, and metal particles provided with appropriate opening / closing means on the side wall of the reaction tower 1 immediately above the dispersion plate 4. A take-out port 10 is provided.

  A first cylinder 20 is flange-bonded to the upper end of the reaction tower 1. The first cylinder 20 is made of the same material as the reaction tower 1 and constitutes a part of the reaction tower in the switchable chemical loop combustor A. A preheating burner 21 is attached to the first cylindrical body 20 so as to penetrate the side wall. In this example, the preheating burner 21 is an air combustion burner, and includes a combustion gas supply nozzle 22 and an air nozzle 23. Further, a thermometer 24 is attached to the first cylindrical body 20 so that the detection unit reaches the reaction tower 1.

  A second cylinder 30 is flange-joined to the upper end of the first cylinder 20. The second cylinder 30 is made of the same material as the reaction tower 1 and constitutes a part of the reaction tower in the switchable chemical loop combustor A. Inside the second cylinder 30, heat exchange means 32 including a large number of heat transfer tubes 31 through which the fluid to be heated (for example, water) flows is attached so as to extend over the entire length of the second cylinder 30. An inlet 33 for the fluid to be heated is attached to the part, and an outlet 34 is attached to the upper end.

  A closing member 40 made of a material capable of sealing the space in the reaction tower is connected to the upper end of the second cylindrical body 30 so that the open lower end side communicates with the second cylindrical body 30. Has been. A proper number (three in this example) of ceramic filters 41a, 41b, and 41c are provided in the closing member 40 so as to extend over the entire horizontal cross section, and the upper portions of the respective filters are partitioned. The chambers 42a, 42b, and 42c are provided. A sensor 40a for checking the exhaust gas temperature is attached to the space below the filters 41a, 41b, 41c in the closing member 40. The filter can also be made of a heat resistant material such as a nickel stainless alloy or a chrome stainless alloy.

  Next, the piping system attached to the switching chemical loop combustion apparatus A will be described. An air supply system 50 and a fuel supply system 60 are connected to the nozzle 8 through a pipe 51 and a pipe 61. The air supply system 50 includes a blower 53, a shut-off valve 54, a flow meter 55, a pressure regulating valve 56, a check valve 57, and the like, and is a regulated and quantified air functioning as an oxidizing agent (an example of an oxidizing agent). Is not limited to this, but is supplied into the inner cylinder 5 through the pipe 51 and the nozzle 8. The fuel supply system 60 includes a shutoff valve 64, a flow meter 65, a pressure regulating valve 66, a check valve 67, and the like, and is a regulated and quantified fuel gas such as a city gas that functions as a reducing agent (an example of a reducing agent). (But not limited to this) is supplied into the inner cylinder 5 through the pipe 61 and the nozzle 8.

  The air supply system 50 corresponds to the “oxidant supply system” in the present invention. The fuel supply system 60 is for supplying a reducing agent to the reaction tower 1 and corresponds to the “reducing agent supply system” in the present invention. As the reducing agent, a material such as methane gas is usually supplied as a fuel gas, so that it is referred to as “fuel supply system 60”. The “oxidant supply system” and “reducing agent supply system” constitute the “gas supply means” in the present invention.

A purge gas supply system 70 is connected to the gas supply pipe 9 via a pipe 71. The purge gas supply system 70 is for supplying an inert gas as a purge gas into the reaction tower 1 and constitutes a “purge gas supply means” in the present invention. The purge gas supply system 70 includes a purge gas tank 73, a shut-off valve 74, a flow meter 75, a pressure regulating valve 76, a check valve 77, and the like, and inert gas such as CO ₂ and N ₂ stored in the purge gas tank 73 is stored therein. It is supplied into the reaction tower 1 through the pipe 71 and the gas supply pipe 9.

  Pipings 43a, 43b, 43c extend from the top plates of the chambers 42a, 42b, 42c of the closing member 40 described above, and a first inlet port and an outlet port are connected to each of the pipes 43a, 43b, 43c. Thus, the three-way valves 44a, 44b, and 44c are interposed. The outlet ports of the three-way valves 44a, 44b, and 44c are connected to the suction port of the blower 45 with an inverter, and the branch pipe 47 from the pipe 46 on the outlet side of the blower 45 is connected to the three-way valves 44a, 44b. , 44c is connected to the second incoming port. Therefore, by appropriately controlling each of the three-way valves 44a, 44b, 44c by a control device (not shown), for example, as shown in FIG. 1, the exhaust gas that has passed through the two filters 41a, 41b is converted into the two three-way valves 44a. , 44b is sucked by the blower 45 through the first inlet port and the outlet port, and a part of the exhaust gas blown from the blower 45 is passed through the branch pipe 47 to the second input of the three-way valve 44c to the remaining filter 41c. When the filter 41c is set so as to be introduced into the side port and exhausted from the first entry side port, a process for backwashing the filter 41c becomes possible. Thereby, clogging of the filter can be avoided. Of course, an operation of sucking all exhaust gas passing through the three filters 41a, 41b, and 41c by the blower 45 is naturally possible. A gas sensor 48 that detects the concentration of oxygen, nitrogen, or carbon dioxide gas is attached to the piping 46 on the ejection side of the blower 45.

An N ₂ exhaust system 80 is connected downstream of the branch pipe 47 in the blower 45 on the ejection side of the blower 45, and a CO ₂ exhaust system 90 is connected in parallel therewith. A purge gas exhaust pipe 100 branches from each of the N ₂ exhaust system 80 and the CO ₂ exhaust system 90. The N ₂ exhaust system 80, the CO ₂ exhaust system 90, and the purge gas exhaust pipe 100 constitute the “exhaust gas exhaust means” in the present invention.

In this example, the N ₂ exhaust system 80 includes a shut-off valve 81, a heat exchanger 82, an exhaust gas sensor 83, a pressure regulating valve 84, a check valve 85, and an N ₂ tank 86 in this order from the upstream side to the downstream side. Yes. Similarly, in this example, the CO ₂ exhaust system 90 includes a shut-off valve 91, a heat exchanger 92, an exhaust gas sensor 93, a pressure regulating valve 94, a check valve 95, and a CO ₂ tank 96 in this order from the upstream side to the downstream side. I have. A shutoff valve 101 is attached to the purge gas exhaust pipe 100.

  In the illustrated switchable chemical loop combustor A, the blower-side piping 46 of the blower 45 is also connected to the piping 61 of the fuel supply system 60 via the shutoff valve 110, the pressure regulating valve 111, and the check valve 112. . Further, the branch pipe 121 from the pipe 120 from the heated fluid outlet 34 of the heat exchange means 32 is also connected to the pipe 61 of the fuel supply system 60 via the shutoff valve 122, the pressure regulating valve 123, and the check valve 124. Connected to.

A pipe 87 is attached to the N ₂ tank 86 arranged in the N ₂ exhaust system 80, and the pipe 87 is connected to a pipe 71 of the purge gas supply system 70 via a shutoff valve 88 and a check valve 89. ing. Further, the branch pipe 87 a of the pipe 87 is also connected to the pipe 51 of the air supply system 50. The N ₂ tank 86 is also connected to an N ₂ extraction pipe through a shut-off valve.

A pipe 97 is also attached to the CO ₂ tank 96 disposed in the CO ₂ exhaust system 90, and the outlet side of the pipe 97 is connected to the pipe 87 through a shutoff valve 98 and a check valve 99. doing. The CO ₂ tank 96 is also connected to a CO ₂ extraction pipe via a shut-off valve.

In the switchable chemical loop combustor A, the fluid to be heated, which is water, for example, is supplied to the inlet 33 of the fluid to be heated provided at the lower end of the heat exchanging means 32 through the water supply pipe 130. The water supply pipe 130 extends from the heat exchanger 82 provided in the N ₂ exhaust system 80, the heat exchanger 92 provided in the CO ₂ exhaust system 90, and the top plates of the chambers 42a, 42b, and 42c of the closing member 40 described above. It is provided so as to pass through the heat exchanger 49 provided in the pipes 43a, 43b and 43c which are exhaust gas pipes to be discharged, and the temperature is gradually raised by exchanging heat with these heat exchangers. The heated fluid to be heated flows in the heat transfer pipe 31 of the heat exchanger 32, thereby further exchanging heat with the exhaust gas from the reaction tower 1, further raising the temperature, and from the outlet 34 through the pipe 120. , And sent to a steam header of an external heat load (not shown). Therefore, the heated fluid after heat exchange is returned to the water supply pipe 130 again. Further, in the heat exchangers 82 and 92 described above, the water generated as a result of the heat exchange is returned to the water supply tank or the like through the pipe 131.

  The operation of the above-described switchable chemical loop combustor A will be described. In advance, the metal particles M are filled in the reaction tower 1 to a position beyond the upper end of the inner cylinder 5 described above. Preferred examples of the metal particles M include Ni, Cu, Co, Fe, and oxides thereof. After the filling, the preheating burner 21 is ignited, and the inside of the reaction tower 1 is preheated by a preheating means such as an electric heater (not shown) to heat the metal particles M to a temperature close to the temperature at which the oxidation reaction can be started.

The control means (not shown) closes the shutoff valve 64 provided in the fuel supply system 60 and the shutoff valve 74 provided in the purge gas supply system 70 in the gas supply means, and opens the shutoff valve 54 of the air supply system 50. Further, the shutoff valve 91 provided in the CO ₂ exhaust system 90 in the exhaust gas exhaust means is closed, and the shutoff valve 81 provided in the N ₂ exhaust system 80 is opened. The shutoff valve 101 provided in the purge gas exhaust pipe 100 in the N ₂ exhaust system 80 is closed. Then, the blower 53 provided in the air supply system 50 is operated, and a predetermined amount of air (which may be air having an environmental temperature) is supplied to the nozzle 8. The supplied air rises from the nozzle 8 in the inner cylinder 5 described above. As a result of the rise, the metal particles M accommodated in the reaction tower 1 rise in the inner cylinder 5, are ejected into the reaction tower 1 from the upper end of the inner cylinder 5, descend in the reaction tower 1, and again the inner cylinder 5. It repeats the circular movement that flows in. That is, the metal particles M circulate between the inner cylinder 5 and the reaction tower 1. In parallel with the operation, the fluid to be heated is fed into the water supply pipe 130.

  Oxygen in the air supplied into the inner cylinder 5 functions as an oxidizing agent, so that an oxidation reaction stage starts in the inner cylinder 5 and the metal particles M in the inner cylinder 5 become metal oxide particles MO. At that time, heat of reaction due to the oxidation reaction is generated, and the high-temperature exhaust gas heated by the heat passes through the heat exchanger 32. At that time, the fluid to be heated flowing in the heat transfer tube 31 of the heat exchanger 32 is heated. The high-temperature exhaust gas that has contributed to the oxidation reaction then passes through the filters 41a, 41b, and 41c provided in the chambers 42a, 42b, and 42c of the closing member 40, and is sent to the ejection side pipe 46 by the blower 45. . By passing through the filters 41a, 41b and 41c, the solid content such as metal particles contained in the exhaust gas is captured up to fine particles having a diameter of about several μm, and the exhaust gas discharged does not contain solid content.

Next, the exhaust gas passes through the N ₂ exhaust system 80 from the pipe 46. The main component of the exhaust gas from which O ₂ has been removed by the oxidation reaction is high-concentration N ₂ gas. However, since O ₂ may remain, component analysis is performed by passing the exhaust gas sensor 83. Thereafter, the exhaust gas passes through the heat exchanger 82, thereby exchanging heat with the heated fluid flowing in the feed water pipe 130 and condensing water vapor to separate it as water. The exhaust gas after the heat exchange is sent into the N ₂ tank 86 and stored as high-concentration N ₂ gas. The fluid to be heated, which has been heated by exchanging heat with the reaction heat, is sent to an appropriate steam header as described above, and is used as a heat source for an on-site boiler or industrial furnace, for example.

By continuing the supply of air into the inner cylinder 5, the oxidation reaction of the metal particles M proceeds continuously. After continuing the oxidation reaction stage for a predetermined time, the control means closes the shut-off valve 54 of the air supply system 50 and opens the shut-off valve 74 provided in the purge gas supply system 70. At that time, the shutoff valve 64 provided in the fuel supply system 60 is kept closed. Thereby, in place of air, an inert gas (preferably N ₂ gas) stored in the purge gas tank 73 is fed into the reaction tower 1 as a purge gas. At that time, the shutoff valve 101 attached to the purge gas exhaust pipe 100 provided in the N ₂ exhaust system 80 in the exhaust gas exhaust means is opened.

The exhaust gas containing high-concentration N ₂ generated in the oxidation reaction stage remaining in the reaction tower 1 by the supply of the purge gas (which may contain O ₂ as described above) is combined with the purge gas in the reaction tower 1. From the exhaust gas sensor 48 or 83 to the exhaust gas sensor 48 or 83, the component analysis is performed, and then the exhaust gas is exhausted from the purge gas exhaust pipe 100 provided in the N ₂ exhaust system 80 to the outside of the system.

After the exhaust gas sensor 83 no longer detects O _{2 in} the exhaust gas generated in the oxidation reaction stage, the control means closes the shut-off valve 74 provided in the purge gas supply system 70 in the gas supply means, and is provided in the fuel supply system 60. Open the shut-off valve 64. The shutoff valve 54 of the air supply system 50 is kept closed. Further, the shutoff valve 91 provided in the CO ₂ exhaust system 90 is opened, and the shutoff valve 101 of the purge gas exhaust pipe 100 provided there is closed. The shutoff valve 81 provided in the N ₂ exhaust system 80 is closed.

As a result, a fuel gas such as methane that functions as a reducing agent is fed to the inner cylinder 5 accommodated in the reaction tower 1 instead of the purge gas. The supplied fuel gas rises from the nozzle 8 in the inner cylinder 5 described above. As a result of the rise, the metal oxide particles MO accommodated in the reaction tower 1 rise in the inner cylinder 5 as in the case of the metal particles M in the oxidation reaction stage, and enter the reaction tower 1 from the upper end of the inner cylinder 5. The movement which descends and falls in the reaction tower 1 and flows into the inner cylinder 5 again is repeated. That is, the metal oxide particles MO are circulated between the inner cylinder 5 and the reaction tower 1. In the process, a reduction reaction stage in which the supplied fuel gas and the metal oxide particles MO undergo a reduction reaction proceeds, and the metal oxide particles MO are returned (reduced) to the metal particles M. At this stage, O ₂ is not present in the reaction tower 1 due to the supply of the purge gas, and it is avoided that the fuel gas directly burns with air.

The exhaust gas after contributing to the reduction reaction is high-concentration CO ₂ gas and H ₂ O (water vapor), and the exhaust gas passes through the CO ₂ exhaust system 90 from the pipe 46. That is, the exhaust gas passes through the filters 41a, 41b, and 41c to remove the solids contained in the exhaust gas, and then passes through the exhaust gas sensors 48 and 93 to perform component analysis. Further, the exhaust gas passes through the heat exchanger 92, thereby exchanging heat with the heated fluid flowing in the feed water pipe 130 and condensing water vapor to separate it as water. The separated exhaust gas having a high concentration of CO ₂ gas is sent to the CO ₂ tank 96 and stored.

When it is detected from the information from the exhaust gas sensor 93 that the reduction of the metal oxide particles MO to the metal particles M is almost finished (whether the reduction of the metal oxide particles MO to the metal particles M is almost finished is determined by the exhaust gas. The control means closes the shut-off valve 64 provided in the fuel supply system 60 in the gas supply means, and is provided in the purge gas supply system 70, which can be known by measuring the amount of reducing agent, for example, methane contained therein. Open the shut-off valve 74 again. The shutoff valve 34 of the air supply system 50 is kept closed. Further, the shutoff valve 101 of the purge gas exhaust pipe 100 provided in the CO ₂ exhaust system 90 is opened.

Thereby, in place of the fuel gas, the inert gas (preferably CO ₂ gas) stored in the purge gas tank 73 is fed into the reaction tower 1 as the purge gas. By supplying the purge gas, fuel gas such as methane remaining in the reaction tower 1 is discharged together with the purge gas from the reaction tower 1 toward the pipe 46, and component analysis is performed by passing through the exhaust gas sensor 48 or 93. After that, the purge gas exhaust pipe 100 provided in the CO ₂ exhaust system 90 is released to the atmosphere.

After the exhaust gas sensor 93 no longer detects a reducing agent such as methane, the control means closes the cutoff valve 74 provided in the purge gas supply system 70 in the gas supply means and opens the cutoff valve 54 of the air supply system 50. The shutoff valve 64 provided in the fuel supply system 60 is kept closed. Further, the shutoff valve 91 provided in the CO ₂ exhaust system 90 is closed, and the shutoff valve 81 provided in the N ₂ exhaust system 80 is opened. The shutoff valve 101 provided in the purge gas exhaust pipe 100 attached to the N ₂ exhaust system 80 is closed. This state is the same as that at the start of the above-described oxidation reaction stage. Hereinafter, the oxidation reaction stage, the purge gas supply, the reduction reaction stage, and the purge gas supply are repeatedly advanced so that the chemical loop combustion is performed in one reaction tower 1. Continue in.

  In the switchable chemical loop combustor A having the above-described piping system, a part of the heated fluid flowing out from the outlet 34 of the heat exchange means 32 is supplied to the piping 121, the shutoff valve 122, the pressure regulating valve 123, and the check valve 124. Thus, the fuel can be selectively supplied into the pipe 61 of the fuel supply system 60. As a result, the reduction reaction between the reducing agent in the fuel gas and the metal oxide particles MO can be promoted, and an inexpensive metal such as Fe is used as a metal particle effective for chemical loop combustion. Is possible. Furthermore, it becomes possible to effectively use a city gas containing a slow-reactive hydrocarbon such as methane as a highly reactive reducing agent.

Further, in the illustrated switchable chemical loop combustor A, a part of the exhaust gas flowing through the pipe 46 is selectively passed through the shutoff valve 110, the pressure regulating valve 111, and the check valve 112 to the pipe 61 of the fuel supply system 60. It can be supplied inside. In chemical loop combustion, the supply amount of fuel gas as a reducing agent is generally smaller than the supply amount of air as an oxidant, so that the metal oxide particles MO cannot be sufficiently fluidized in the reduction reaction stage. In the switchable chemical loop combustor A described above, there is a possibility that the exhaust gas (that is, CO ₂ , H ₂ O) is recirculated through the pipe 61 of the fuel supply system 60 to be introduced into the reaction tower 1. The flow rate of the particles can be increased to improve the flow state of the particles. Further, by adjusting the recirculation amount, the fluidization state can be adjusted without changing the input amount of the fuel gas.

Moreover, the switchable Chemical loop combustor A having a piping system as described above, the N ₂ tank 86 disposed in the N ₂ exhaust system 80, together with the pipe to retrieve the stored the N ₂ to the outside, the retention of N ₂ one This portion can be selectively supplied into a pipe 71 connecting the purge gas supply system 70 and the reaction tower 1 via a pipe 87. Furthermore, a part of the stored N ₂ can be selectively supplied into the pipe 51 connecting the air supply system 50 and the nozzle 8 attached to the reaction tower 1 through the branch pipe 87a.

In addition, the tank 96 which is provided in the CO ₂ exhaust system 90, together with the pipe to retrieve the stored the CO ₂ to the outside through a pipe 97, a part of the reservoir the CO ₂ purge gas supply line 70 and the reaction column 1 It can be selectively supplied into the pipe 71 to be connected.

As described above, even when it is desired to reduce the flow rate of the supplied air by adding the N ₂ gas flowing through the N ₂ exhaust system 80 to the air supplied into the reaction tower 1 (inner cylinder 5), the reaction tower 1 (inner The apparent flow rate to the cylinder 5) can be increased, and the flow rate of the input gas to the reaction tower 1 (inner cylinder 5) can be arbitrarily changed even if the amount of air input from the outside is small. Further, by supplying the CO ₂ gas flowing through the N ₂ gas and CO ₂ exhaust system 90 through the N ₂ exhaust system 80 in the pipe 71 for the purge gas, it can be self-sufficient supply of inert gas as a purge gas Accordingly, it is possible to eliminate the supply of the inert gas from the outside.

Note that when the operation of the switched Chemical looping combustion device A described above, from the CO ₂ exhaust system 90 to retrieve as much as possible a high concentration of CO ₂ gas, the fuel gas from the start to the end feed time (fuel gas being supplied ), An operation method for delaying the opening timing of the shut-off valve 91 provided in the CO ₂ exhaust system 90 so as to exhaust from the CO ₂ exhaust system 90 only during the time when the CO ₂ concentration becomes high, and N ₂ exhaust In order to extract the N ₂ gas from the system 80 to the highest possible concentration, the exhaust gas is exhausted from the N ₂ exhaust system 80 only during the time when the N ₂ concentration is high during the air supply time (from the start to the end of air supply). An operation method that delays the opening timing of the shut-off valve 81 provided in the N ₂ exhaust system 80 can also be adopted.

When such an operation method is employed, while the shutoff valve 81 provided in the N ₂ exhaust system 80 is closed while being in the oxidation reaction stage, the shutoff valve 91 provided in the CO ₂ exhaust system 90 and While the shut-off valve 101 attached to the provided purge gas exhaust pipe 100 is opened, and while the shut-off valve 91 provided in the CO ₂ exhaust system 90 is closed while being in the reduction reaction stage, the N ₂ exhaust system 80 By opening the shut-off valve 81 provided on and the shut-off valve 101 attached to the purge gas exhaust pipe 100 also received there, it becomes possible to continue chemical loop combustion.

  In the above-described switchable chemical loop combustor A, clogging may occur in the ceramic filters 41a, 41b, and 41c by continuously operating. At that time, as described above, the control device appropriately controls the opening and closing of the three-way valves 44a, 44b, 44c, and reverses the flow direction of the exhaust gas in the clogged filters 41a, 41b, 41, Clogging can be resolved automatically.

[Second form]
FIG. 2 shows a switching chemical loop combustor according to the present invention together with a piping system to which a second embodiment is attached. The switchable chemical loop combustor B of the second embodiment is different from the switchable chemical loop combustor A of the first embodiment shown in FIG. 1 in that the inner cylinder 5 and the nozzle 8 are not provided. . The piping system is the same as in the case of the switchable chemical loop combustor A of the first embodiment except for a part, and the description of the same part is omitted by giving the same reference numeral.

Since the switchable chemical loop combustor B of the second embodiment does not include the inner cylinder 5, the oxidant gas (air), the reductant gas (fuel gas), the purge gas (N ₂ , CO ₂ ) into the reaction tower 1 are included. The supply of ₂ ) is all performed through the gas supply pipe 9 having an outlet in the space between the bottom plate 3 and the dispersion plate 4 of the reaction tower 1. That is, in the switchable chemical loop combustor B of the second embodiment, the outlet side pipe 61 of the fuel supply system 60 and the outlet side pipe 71 of the purge gas supply system 70 are connected to the pipe 9a connected to the gas supply pipe 9. And the outlet side piping 51 of the air supply system 50 is connected. In addition, the timing of supply start and supply stop of each gas is the same as that of the switchable chemical loop combustor A of the first embodiment.

[Third embodiment]
FIG. 3 shows a switching chemical loop combustor according to the present invention together with a piping system to which a third embodiment is attached. The switchable chemical loop combustor C of the third embodiment is different from the switchable chemical loop combustor A of the first embodiment in that the ceramic filters 41a, 41b, 41c are not provided in the closing member 40, and therefore The difference is that the three-way valves 44a, 44b, and 44c are not provided. The piping system is the same as in the case of the switchable chemical loop combustor A of the first embodiment except for the piping portions related to the three-way valves 44a, 44b, 44c, etc. Description is omitted.

  In the switchable chemical loop combustor C of the third embodiment, the closing member 40 merely closes the upper end of the reaction tower, and only one pipe 43 extends from the top surface thereof. The other end of the pipe 43 is connected to the inlet side of the solid-gas separation type cyclone 140. The exhaust side of the solid-gas separation type cyclone 140 is connected to the suction port of the blower 45 described above. Since the switchable chemical loop combustor C of the third embodiment does not have the ceramic filter 41, the exhaust gas discharged from the reaction tower may contain solids such as metal particles M or metal oxide particles MO. There is. However, since the contained solid matter is removed by the solid-gas separation type cyclone 140, it is possible to avoid clogging of the piping.

[Fourth form]
FIG. 4 shows a switching chemical loop combustor according to the present invention together with a piping system to which a fourth embodiment is attached. In the switchable chemical loop combustor D of the fourth form, the metal M as a medium contributing to the redox reaction is not a particulate metal or an oxide of the particulate metal that can flow in the reaction tower 1. In the case of the above-described switchable chemical loop combustors A to C, in that it is a particulate metal supported on a honeycomb-shaped carrier or an oxide of the particulate metal (hereinafter referred to as medium metal particles). It is different.

The honeycomb-like structure serving as a carrier can be made of any material as long as it can support the medium metal particles and has heat resistance and required mechanical strength. Suitable materials include ceramics such as alumina (Al ₂ O ₃ ) and silicon carbide (SiC). These materials can be obtained by extrusion-molding such that a plurality of communication holes having a predetermined length are arranged in the same direction without gaps, and firing them. A smaller diameter of each communication hole is preferable because the entire surface area (reaction area) is large, but there is a disadvantage that the pressure loss is large. Depending on the design output of the switchable chemical loop combustor D, about 600 to 1200 cpsi (number of cells per inch square) is preferable.

  As an example of such a honeycomb structure, a honeycomb structure for a three-way catalyst used for exhaust gas treatment of automobiles can be given. A technique for supporting the medium metal particles on the honeycomb structure may be performed by a conventionally known support technique. For example, the honeycomb structure is immersed in a solution containing the target medium metal particles, and the medium metal particles are immersed in the honeycomb structure. Can be attached together with the solution, and then dried and then baked.

  In the switchable chemical loop combustor D, the honeycomb-like structure 150 supporting the medium metal particles thus manufactured is arranged in a fixed state in the reaction tower 1. In the example shown in FIG. 4, a “metal M as a medium” is formed by stacking the required number of plate-like honeycomb-like structures 150 having a flat area that can cover the horizontal section of the reaction tower 1. ing. In addition, when the honeycomb structure 150 is stacked in multiple stages, it is necessary to arrange the communication holes so as to be continuous in the gas flow direction.

More specifically, in the switchable chemical loop combustor D of the fourth embodiment, supply of oxidant gas (air), reducing agent gas (fuel gas), and purge gas (N ₂ , CO ₂ ) into the reaction tower 1. Are all provided with a gas supply pipe 9 having an outlet in the space between the bottom plate 3 and the dispersion plate 4 of the reaction tower 1, as in the switchable chemical loop combustor B of the second form shown in FIG. Done through. And the metal M as a medium which consists of the above-mentioned honeycomb-like structure 150 is fixed to the upper position in the reaction tower 1 which is away from the dispersion plate 4 by a certain distance. Further, the same preheating burner 21 as described above is attached to the peripheral wall of the reaction tower 1 between the dispersion plate 4 and the lower end portion of the metal M as a medium composed of the honeycomb structure 150.

  Moreover, in the switching type chemical loop combustor D of the fourth embodiment, the particulate metal flowing in the reaction tower 1 is not used as the metal as the medium, so that the metal particles are not scattered in the reaction tower. . Therefore, as shown in the figure, the closing member 40 is a member having a function of simply closing the upper end of the reaction tower as in the case of the switchable chemical loop combustor C of the third embodiment shown in FIG. However, unlike the switchable chemical loop combustor A of the first form or the switchable chemical loop combustor B of the second form, it is not necessary to use the filter 41 made of ceramics. Then, it is only necessary to extend one pipe 43 from the top surface of the closing member 40 and connect it to the suction port of the blower 45. Therefore, the configuration is also simplified. Of course, as shown in the figure, the exhaust end of the pipe 43 is connected to the solid-gas separation type cyclone 140, and the exhaust side of the solid-gas separation type cyclone 140 is connected to the suction port of the blower 45, so that the pipe is clogged. This can be avoided more reliably.

The operation mode of the switchable chemical loop combustor D, the timing of starting and stopping the supply of each gas, and the like are substantially the same as those in the switchable chemical loop combustor A of the first embodiment, and are given the same reference numerals. Therefore, the description about the same part is abbreviate | omitted. In the switchable chemical loop combustor D, when the oxidant gas (air) supplied from the gas supply pipe 9 passes through the through-hole formed in the honeycomb structure 150 supporting the medium metal particles. The oxidation reaction of the medium metal particles carried thereon proceeds, and when the reducing agent gas (fuel gas) passes, the reduction reaction of the oxidized medium metal particles proceeds. Further, when the purge gas (N ₂ , CO ₂ ) passes, purging of the oxidant gas or the reductant gas remaining in the through hole proceeds. Thereby, the chemical loop combustion can be continuously advanced as in the case where the particulate metal flowing in the reaction tower 1 is used as the metal as the medium.

[Fifth embodiment]
Although not shown, as a modified example of the switchable chemical loop combustor D, a “metal as a medium” is made of a honeycomb-like metal or metal oxide that is the same kind of particulate metal that can flow in the reaction tower. There is also a form in which a structure is formed and fixed in the reaction tower 1 in place of the honeycomb-shaped carrier supporting the medium metal particles in the switching chemical loop combustor D described above. Even in this case, it is not necessary to explain that the intended purpose of the switched chemical loop combustor can be achieved in the same manner as the switched chemical loop combustor D.

[Sixth embodiment]
Although not shown, as a modification of the switchable chemical loop combustor B shown in FIG. 2, there may be mentioned a form in which the ceramic filter 41 is not provided. Even in this form, it is not necessary to explain that the intended purpose can be achieved.

[Seventh form]
Although not shown, as a modification of the switchable chemical loop combustors A to C, the heat exchanger 32 is not in a form in which the heat exchanger 32 is positioned in the upper space where the metal particles do not exist, but a heat transfer tube through which an unheated fluid passes is provided. You may make it arrange | position in the reaction tower 1 in which a metal particle exists. Even in this aspect, it is not necessary to explain that the intended purpose of the switchable chemical loop combustor can be achieved.

[Eighth form]
Although not shown in the drawings, the above-described purge gas supply means can be omitted in all the above-described switched chemical loop combustors. In that case, it is inevitable that the combustion efficiency is reduced and the CO ₂ gas and N ₂ gas from the exhaust gas are separated and recovered, but there is an advantage that the apparatus can be simplified.

A to D: Switchable chemical loop combustor,
1 ... reaction tower,
5 ... Inner cylinder,
8 ... Nozzle,
9: Gas supply pipe,
10 ... Metal particle outlet,
21 ... Burner for preheating,
31 ... Heat transfer tube,
32 ... heat exchange means,
33 ... Inlet of heated fluid,
34: Heated fluid outlet,
40. Closure member,
41 ... Ceramic filter,
44 ... 3-way valve,
45 ... Blower,
50 ... Air supply system,
60 ... Fuel supply system,
70 ... purge gas supply system,
80 ... N ₂ exhaust system,
86 ... N ₂ tank,
90 ... CO ₂ exhaust system,
96 ... CO ₂ tank,
100 ... Purge gas exhaust pipe,
130 ... water supply piping,
150... A honeycomb-shaped carrier carrying particulate metal or an oxide of the particulate metal.

Claims (10)

A chemical loop combustion is performed in which a metal as a medium that contributes to the oxidation-reduction reaction reacts with an oxidant to form a metal oxide, and a reduction reaction stage in which the metal oxide undergoes reduction by the reductant repeatedly proceeds. A chemical loop combustor for
One reaction column containing the metal as the medium;
A gas supply means for alternately supplying an oxidizing agent and a reducing agent into the reaction tower;
Exhaust gas exhaust means for exhausting exhaust gas from the reaction tower;
With at least,
The metal as the medium is a honeycomb structure fixed to the reaction tower, a particulate metal supported on a honeycomb-shaped carrier fixed to the reaction tower, or an oxide of the particulate metal. switchable Chemical looping combustion device, characterized in that it. Switchable Chemical looping combustion of claim 1, characterized in that it comprises a preheating burner for preheating the metal as the medium of the reaction column. The switchable chemical loop combustor according to claim 1, further comprising heat exchange means having a heat transfer tube through which a fluid to be heated flows in the reaction tower. The switchable chemical loop combustor according to claim 3 , wherein the heat exchange means is installed at a position away from an upper surface of a metal as the medium accommodated in the reaction tower. 2. A purge gas supply means for supplying an inert gas as a purge gas into the reaction tower between the oxidation reaction stage and the reduction reaction stage and between the reduction reaction stage and the oxidation reaction stage. The switchable chemical loop combustor as described in any one of thru | or 4 . The flue gas exhaust means, CO ₂ for exhausting the N ₂ exhaust system for exhausting the N ₂ rich flue gas generated in the oxidation reaction stage in the reaction column, the CO ₂ rich flue gas generated in the reduction reaction stage in the reaction column 6. The switchable chemical system according to claim 5 , comprising three exhaust systems: an exhaust system and a purge gas exhaust system for exhausting exhaust gas containing purge gas generated when purge gas is supplied into the reaction tower. Loop combustor. The gas supply means includes an oxidant supply system for supplying an oxidant into the reaction tower and a reductant supply system for supplying a reductant into the reaction tower, and the purge gas supply means includes a purge gas in the reaction tower. The switchable chemical loop combustor according to claim 5 , further comprising a purge gas supply system for supplying the gas. The switchable chemical loop combustor according to claim 7 , further comprising a piping system that returns the CO ₂ rich exhaust gas generated in the reduction reaction stage to the reducing agent supply system. The switchable chemical loop combustor according to claim 7 , further comprising a piping system for returning N ₂ gas contained in the N ₂ rich exhaust gas generated in the oxidation reaction stage to the oxidant supply system. N ₂ and CO ₂ gas contained in the N ₂ gas and CO ₂ rich exhaust gas contained in the rich exhaust gas to one of claims 5 to 9, further comprising a piping system for supplying said purge gas supply means Switchable chemical loop combustor as described.

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