JP5759745B2 - Chemical loop combustion device and heat utilization system equipped with the same - Google Patents

Description

  The present invention relates to a chemical loop combustion apparatus and a heat utilization system including the chemical loop combustion apparatus.

  A chemical loop combustion method in which heat is obtained by circulating metal particles and metal oxide particles between an oxidation reaction system that oxidizes metal particles and a reduction reaction system that reduces metal oxide particles is known. In chemical loop combustion, instead of burning fuel directly with air, the combustion reaction is divided into two parts, "oxidation of metal particles" and "reduction of metal oxide particles", and the two are connected by physical particle circulation. It is. There is no direct contact between fuel and air, and pure oxygen is exchanged using metal as a medium.

In chemical loop combustion, hydrocarbon fuel such as methane functions as a reducing agent for metal oxide in the reduction reaction system, and only the air and metal particles as the oxidant are supplied to the oxidation reaction system. Heat is generated by the oxidation reaction. Usually, the temperature generated by the oxidation reaction is about 800 to 1200 ° C., and the exhaust gas, which is mainly N ₂ , has a relatively low temperature, so thermal NOx is hardly generated. Further, in the reduction reaction system, there are only oxygen supplied from hydrocarbons and metal oxides as fuel, so that the exhaust gas components are substantially only carbon dioxide and water. Therefore, if the exhausted gas is cooled to remove water, almost pure CO ₂ can be easily recovered.

  Because of the above advantages, an apparatus for actually carrying out chemical loop combustion has already been proposed, and Patent Document 1 or 2 describes a power plant system using a chemical loop combustion method.

  In addition, as described in Non-Patent Document 1, as a chemical loop combustion system, a so-called internal circulation system in which a reduction tower is incorporated inside an oxidation tower and an oxidation tower and a reduction tower are separated. A so-called external circulation system is proposed in which both are connected by a flow path of oxidized metal particles and a flow path of reduced metal particles.

JP 05-332161 A JP 2000-337168 A

External circulation: 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 Internal circulation: Experimental results of chemical-looping combustion with NiO / NiAl2O4 particle circulation at 1200 degrees C Ishida M, Yamamoto M, OhbaTENERGY CONVERSION AND MANAGEMENT 2002, 43,9-12,1469-1478

As described in Patent Document 1 or 2, research for the practical use of chemical loop combustion is currently being conducted mainly for power generation, and the combustion apparatus also employs an external circulation type CO ₂ capture system. At present, research and development is undertaken assuming large-sized molds. There has been little research and development on technology that uses heat generated by chemical loop combustion equipment in on-site industrial boilers and industrial furnaces.

  Chemical loop combustion used for power generation tends to increase in size for the following reasons. That is, in the chemical loop combustion, it is required to stably fluidize the metal fine particles, so that the superficial velocity in the reaction tower is within a certain range (for example, depending on the particle amount and the particle size) (for example, 0.1 to 0.4 m / s), it is necessary to control the exhaust gas discharged from the oxidation tower. If the temperature of the exhaust gas discharged from the oxidation tower is increased, the actual flow rate of the gas (exhaust gas) depends on the temperature due to temperature expansion. Increases and increases the superficial velocity. Therefore, it is necessary to suppress the superficial velocity by increasing the cross-sectional area of the reaction tower (oxidation tower). On the other hand, when using the exhaust gas from the chemical loop combustion device for power generation, it is required to raise the exhaust gas extraction temperature in order to improve the power generation efficiency of the gas turbine. As a result, the chemical loop combustion device is enlarged. Tend to.

  It is usually not easy to install many chemical loop combustors that tend to be large in the vicinity of factories or in each factory. For this reason, as described above, the heat of exhaust gas emitted from chemical loop combustors Research and development on the use of as a heat source for on-site boilers, industrial furnaces, etc., and in turn, research and development on improving the convenience of chemical loop combustion equipment have not progressed sufficiently.

  This invention is made | formed in view of the above situations, and makes it possible to utilize the oxidation reaction heat with an industrial boiler and an industrial furnace on-site, without enlarging a chemical loop combustion apparatus. Thus, it is an object to provide a chemical loop combustion apparatus with greatly improved convenience. It is another object of the present invention to provide a heat utilization system including the chemical loop combustion apparatus.

  In the chemical loop combustion apparatus according to the present invention, an oxidation tower in which metal particles react with an oxidant to generate an oxide of the metal particles, and an oxide of metal particles generated in the oxidation tower react with a reducing agent. A chemical column combustion apparatus comprising a reduction tower that is reduced to the metal particles, wherein the metal particles are circulated between the oxidation tower and the reduction tower while undergoing oxidation and reduction, A heat transfer tube for transferring reaction heat to the fluid to be heated in contact with the metal particles or the oxide thereof is disposed in the oxidation tower or the reduction tower (Claim 1).

In the chemical loop combustion apparatus according to the present invention, a heat transfer tube is arranged in the oxidation tower or the reduction tower, and the fluid to be heated flowing in the heat transfer pipe comes into contact with the metal particles or the oxide thereof to generate heat of reaction. Absorbs into a hot liquid. For example, in a mode in which the heat transfer tubes are arranged in the oxidation tower, the heat transfer tubes are in direct contact with the metal particles generated by the oxidation reaction with the oxidizing agent (input air) and the air heated by the generated metal particles, The heat is transferred to the heated fluid flowing in the heat transfer tube. That is, in the oxidation tower, the heat generated by the oxidation reaction of the metal particles is exchanged with the heated fluid flowing in the heat transfer tube. Therefore, the temperature of the input air (exhaust gas) mainly N ₂ discharged from the oxidation tower does not increase greatly, and the average temperature of the input air passing through the oxidation tower also decreases. As a result, since the superficial velocity is suppressed, the cross-sectional area of the oxidation tower can be reduced. As a result, the chemical loop combustion apparatus can be reduced in size, the surface area per combustion amount can be suppressed, and the heat dissipation loss can be reduced.

  Further, in the aspect in which the heat transfer tube is arranged in the reduction tower, the metal particles holding the heat generated by the exothermic reaction in the oxidation tower circulate to the reduction tower and come into contact with the heat transfer pipe to The heated fluid is heated.

  Since chemical loop combustion generates heat mainly due to metal oxidation reaction, there is no combustion flame unlike a normal combustor, and a high-temperature portion of 1500 degrees or more is not formed. Furthermore, in the present invention, heat is directly transferred between the generated metal particles and the heat transfer tube to quench the temperatures of the metal particles and the combustion gas. By performing these two effects simultaneously, the NOx emission amount can be made substantially zero in the chemical loop combustion apparatus according to the present invention.

  Furthermore, the chemical loop combustion apparatus according to the present invention can be miniaturized as described above, and the heat of the heated fluid flowing in the heat transfer tube can be used as a heat source for an on-site boiler, an industrial furnace, or the like. .

  The overall shape of the chemical loop combustion apparatus according to the present invention is such that one or more reduction towers are incorporated in the oxidation tower, or one or more oxidation towers are incorporated in the reduction tower. A so-called internal circulation type may be incorporated (Claims 2 and 3), and the oxidation tower and the reduction tower are separated from each other, and the flow path for the oxidized metal particles and the flow path for the reduced metal particles It may be a so-called external circulation type connected by means of (Claim 4). In either type, one or a plurality of heat transfer tubes are arranged in the oxidation tower. When arranging a plurality of heat transfer tubes, the heat transfer tubes may be arranged at a distance or may be arranged in close contact so as to form a wall. In any form, the form of the reduction tower may be a conventionally known form of the reduction tower.

  In a preferred form of the chemical loop combustion apparatus according to the present invention, headers are provided in the vicinity of the upper part and the lower part of the oxidation tower, and the heat transfer tubes are arranged in the oxidation tower so as to communicate with the upper header and the lower header ( Claim 5). By arranging the upper header and the lower header, the circulation of the heated fluid between the heat load side (for example, steam utilization equipment) and the chemical loop combustion apparatus becomes smooth, and the effective use of heat is further ensured. .

  An intermediate header may be disposed between the upper header and the lower header, and the heat transfer tube may be disposed in the oxidation tower so as to communicate with the upper header, the intermediate header, and the lower header. By providing the intermediate header, it is possible to obtain advantages such as easy production when changing the material of the heat transfer tube in the portion that directly transfers heat with the particles and the heat transfer tube in the portion that transfers heat with the heated gas.

  The present invention further includes a heat utilization system including any one of the above-described chemical loop combustion apparatus and a heat load portion that consumes heat energy of a fluid to be heated that flows through a heat transfer tube disposed in the chemical loop combustion apparatus. Disclosed (Claim 7). Specific examples of the heat load section include steam utilization equipment (claim 8).

  In the present invention, as the oxidizing agent, oxygen-enriched air, low nitrogen air, or the like can be used in addition to air. Natural gas, LPG gas, by-product gas from steelworks, hydrogen, coal, and the like can also be used as the reducing agent.

  ADVANTAGE OF THE INVENTION According to this invention, the chemical loop combustion apparatus which enabled it to utilize the oxidation reaction heat with an industrial boiler and industrial furnace on-site, without enlarging a chemical loop combustion apparatus is provided. Moreover, the heat utilization system provided with the chemical loop combustion apparatus is provided.

The figure shown with the piping system which attaches the 1st aspect of the internal circulation type | formula and lower supply type apparatus which is the 1st form of the chemical loop combustion apparatus by this invention. The figure shown with the piping system which attaches the 2nd aspect of the internal circulation type | formula and the lower supply type apparatus which is the 1st form of the chemical loop combustion apparatus by this invention. The figure shown with the piping system which attaches the 3rd aspect of the internal circulation type and lower supply type apparatus which is the 1st form of the chemical loop combustion apparatus by this invention. The figure shown with the piping system which attaches the 4th aspect of the internal circulation type | formula and lower supply type apparatus which is the 1st form of the chemical loop combustion apparatus by this invention. The figure shown with the piping system which attaches the external circulation type and lower supply type apparatus which is the 2nd form of the chemical loop combustion apparatus by this invention. The figure shown with the piping system which attaches the internal circulation type and upper supply type apparatus which is the 3rd form of the chemical loop combustion apparatus by this invention. The figure shown with the piping system which attaches the external circulation type | formula and upper supply type apparatus which are the 4th form of the chemical loop combustion apparatus by this invention.

  Hereinafter, several forms of a chemical loop combustion apparatus according to the present invention will be described with reference to the drawings.

<First Mode of First Form>
FIG. 1 shows together with a piping system to which a schematic cross section of a first embodiment in a first embodiment of a chemical loop combustion apparatus according to the present invention is attached. The first form is basically an internal circulation type and lower feed type chemical loop combustion apparatus. And the chemical loop combustion apparatus A1a of the 1st aspect shown in FIG. 1 is equipped with one reduction tower inside the oxidation tower. Details will be described below.

  The chemical loop combustion apparatus A1a has a circular tower-shaped outer tower 1 made of a heat-resistant material such as a steel plate, and an upper end surface of the outer tower 1 is a top plate 2 also made of a heat-resistant material such as a steel plate. It is closed. A circular tower 3 having a smaller diameter than that of the outer tower 1 is attached in the outer tower 1 with the same central axis. The upper end of the circular tower 3 passes through the top plate 2 and extends to the outside of the outer tower 1, and the lower end reaches the vicinity of the lower end of the outer tower 1. In the following description, the outer tower 1 is called an oxidation tower 1 and the circular tower body 3 is called a reduction tower 3.

  A columnar air header 4 concentric with the oxidation tower 1 is attached to the lower end portion of the oxidation tower 1, and the upper end of the air header 4 is an air nozzle 5. The air header 4 is connected to the blower 6, and the air regulated through the flow meter 7 and the pressure regulating valve 8 is sent to the air header 4 and ejected from the air nozzle 5 into the oxidation tower 1. As will be explained later, this air functions as an oxidant.

  A tower-like fuel nozzle 9 is arranged at a central portion of the air header 4 and facing a lower end of the reduction tower 3 so as to maintain a predetermined gap in the vertical direction. The inner diameter of the fuel nozzle 9 is slightly smaller than the inner diameter of the lower end portion of the reduction tower 3. The fuel nozzle 9 is supplied with a regulated fuel, such as methane, through a shutoff valve 10, a pressure regulating valve 11, and a check valve 12, and is ejected toward the lower end opening of the reduction tower 3. As will be described later, this fuel functions as a reducing agent.

In this example, a gap is provided between the fuel nozzle 9 and the air header 4 surrounding the outside, and a tower-like separate gas nozzle 13 is disposed in the gap. The separate gas nozzle 13 is supplied with an inert gas not containing oxygen, such as N ₂ gas or CO ₂ gas, through the pipe 14.

  A circular lower header 15 is attached at the bottom of the oxidation tower 1 so as to surround the outside of the air header 4 described above. The bottom surface of the lower header 15 is a horizontal plane, but the upper surface is a conical surface 16, and the lower end of the conical surface is substantially flush with the air nozzle 5. The outer peripheral surface of the lower header 15 is in contact with the inner peripheral surface of the oxidation tower 1, and a first fluid pipe 18 through which a fluid to be heated flows through a hole 17 formed in the wall surface of the oxidation tower 1 is an outer peripheral surface of the lower header 15. Connected to.

  Above the oxidation tower 1, a tower-like upper header 19 is attached so as to contact the top plate 2. The inner diameter and outer diameter of the upper header 19 are substantially the same as the inner diameter and outer diameter of the lower header 15. A second fluid pipe 21 for a fluid to be heated is connected to the upper header 19 through a hole 20 formed in the top plate 2 of the oxidation tower 1. In this example, the second fluid pipe 21 communicates with a heat load unit 100 such as an on-site steam utilization facility or an industrial furnace.

  A heat-resistant wall 22 of an appropriate thickness made of a heat-resistant material such as a heat-resistant roof tile or a heat-resistant ceramic fiber is formed from the upper conical surface 16 of the lower header 15 to an appropriate upper position along the inner wall of the oxidation tower 1. The upper end surface of the heat-resistant wall 22 is a conical wall 23. An intermediate header 24 having a swash plate shape as a whole is attached so that the lower end surface is along the upper end conical wall 23 of the heat-resistant wall 22, and the inner diameter and the outer diameter of the intermediate header 24 are the same as those of the lower header 15 and the inner diameter. And is almost equal to the outer diameter. A solid-gas separation device 25 is attached to the reducing tower 3 at a position slightly above the position where the intermediate header 24 is attached.

  A plurality of heat transfer tubes 26 are attached in parallel to the central axis of the oxidation tower 1 so that the inner spaces of the lower header 15, the intermediate header 24, and the upper header 19 communicate with each other. In the drawing, the plurality of heat transfer tubes 26 are arranged in a plurality of rows in the radial direction and each example is constituted by a plurality of heat transfer tubes, but the arrangement of the heat transfer tubes 26 in the oxidation tower 1 is arranged. Is optional, and may be appropriately arranged on condition that the flow of the metal particles accommodated in the oxidation tower 1 is not hindered as described later.

  The lower header 15, the intermediate header 24, and the upper header 19 are made of a material having excellent heat resistance. In particular, the heat transfer tube 26 is made of a material and shape having excellent heat resistance and heat conductivity. Further, as will be described later, the heat transfer tube 26 is made of a different material for a portion located between the lower header 15 and the intermediate header 24 and a portion located between the intermediate header 24 and the upper header 19. Is desirable.

An exhaust port 27 is provided at the upper portion of the oxidation tower 1, and exhaust gas from the exhaust port 27 (as will be described later, mainly N ₂ and contains a small amount of O ₂ ) passes through the solid-gas separation device 28 to the outside air. Exhausted.

  The above configuration is a configuration necessary for the operation of the chemical circulation combustion apparatus A1a of the first aspect of the internal circulation type and the lower supply type according to the present invention. The combustion apparatus A1a further includes the following piping system.

The exhaust gas from the exhaust port 27 passes through the solid-gas separator 28 and then passes through the heat exchanger 29. The N ₂ gas that has passed through the heat exchanger 29 is stored in a storage tank (not shown). When necessary, a part of the mixed gas of N ₂ and O ₂ is pressurized by the blower 30 and sent from the pipe 14 to the separator gas nozzle 13 through the shut-off valve 31 and the pressure regulating valve 32.

The exhaust gas discharged from the upper part of the reduction tower 3 (which is CO ₂ and H ₂ O vapor as described later) flows into the steam separator 33 in which cooling water from the outside circulates and liquefies the vapor. After being separated, the exhaust gas containing 90% or more of CO ₂ is discharged to the outside and stored in a storage tank (not shown). When necessary, a part of the exhaust gas containing 90% or more of CO ₂ is pressurized by the blower 34, and sent from the pipe 14 to the separator gas nozzle 13 through the shutoff valve 35 and the pressure regulating valve 32.

  The water generated by the steam separator 33 reaches the heat exchanger 29 via the shutoff valve 36 and the pump 37, and after heat exchange there, passes through the pressure regulating valve 38 and the check valve 39 as necessary. Then, it is supplied as water vapor into the fuel supply line to the fuel nozzle 9.

The operation of the chemical loop combustion apparatus A1a will be described. The metal particles M are filled in the internal space of the oxidation tower 1 in advance. The filling amount is such that the metal particles M do not reach the solid-gas separation device 25 attached to the reduction tower 3. The metal particles M may contain not only metals but also metal oxide particles. Preferable examples of the metal particles M include iron (Fe) or iron oxide (FeO, Fe ₂ O ₃ , Fe ₃ O ₄ ). After the filling, the metal particles M are preheated to about 600 ° C. by a preheating means (not shown) such as a preheating burner arranged in the oxidation tower or an electric heater attached to the peripheral wall of the oxidation tower 1. Further, the lower header 15, the intermediate header 24, the upper header 19, all the heat transfer tubes 26, and the first fluid piping 18 and the second fluid piping 21 are filled with a heated solution such as water.

After preheating or in the middle of preheating, a predetermined amount of air (which may be air at ambient temperature) functioning as an oxidant is supplied to the air header 4 and is ejected from the air nozzle 5 into the oxidation tower 1. A predetermined amount of fuel gas such as methane that functions as a reducing agent is ejected from the fuel nozzle 9 toward the reduction tower 3. Further, an inert gas such as N ₂ or CO ₂ is ejected from the separator gas nozzle 13 toward the oxidation tower 1. At the beginning of operation, the inert gas is supplied from an external inert gas source, or is supplied from an inert gas source stored in a storage tank in the system during the previous operation.

  Air ejected from the air nozzle 5 flows into the oxidation tower 1, and fuel gas from the fuel nozzle 9 flows into the reduction tower 3. At that time, in the chemical loop combustion apparatus A1 described above, the separate gas nozzle 13 is located between the air nozzle 5 and the fuel nozzle 9, and the inert gas is ejected therefrom, so that the air and fuel gas after ejection are mixed. Can be avoided.

In the oxidation tower 1, the metal particles M preheated to the reaction temperature and oxygen in the supplied air react to generate metal oxide particles MO. At that time, heat is generated by the metal oxidation reaction, and the temperature of the metal particles M, the metal oxide particles MO, and the air flowing through the oxidation tower 1 is increased. However, heat is generated by the oxidation reaction of the metal, and a high temperature portion of 1500 degrees or more is not formed, and thermal NOx is not generated as described above. When the metal particles M include the metal oxide particles MO, the metal oxide particles MO correspond to metal oxide particles in a form in which the metal oxide particles are further oxidized. For example, when the metal particle M is Fe ₃ O ₄ , the metal oxide particle MO is Fe ₂ O ₃ or the like.

  The metal oxide particles MO and the remaining metal particles M flow down in the oxidation tower 1 and flow into the reduction tower 3 and then rise in the reduction tower 3. In the process of rising in the reduction tower 3, the metal oxide particles MO are returned to the metal particles M by being reduced by the fuel gas. In the above chemical loop combustion apparatus A1, the upper surface 16 of the lower header 15 is a conical surface that is lowered toward the center, so that the movement of the metal oxide particles MO from the bottom of the oxidation tower 1 to the reduction tower 3 is prevented. Proceed smoothly. Further, the solid component and gas component rising in the reduction tower 3 are separated into solid and gas by the action of the solid-gas separation device 25 in the process of rising, and the gas further rises from the upper part of the reduction tower 3. Exhausted. The solid, that is, the metal particles M and the remaining metal oxide particles MO are returned to the oxidation tower 1.

  In the oxidation tower 1, the metal particles M are fluidized under the action of the air ejected from the air nozzle 5, so that the metal particles M or a part of the oxide MO are initially stored. It can happen that it soars upward. In the chemical loop combustion apparatus A1, the heat-resistant wall 22 is formed on the inner wall surface below the oxidation tower 1, so that the heat-resistant wall 22 above the horizontal cross-sectional area of the region where the heat-resistant wall 22 is formed. The horizontal cross-sectional area of the region where no is formed is large. For this reason, the metal particles M or their oxides MO that have risen into the space above the vicinity of the solid-gas separation device 25 have a low superficial velocity and are likely to fall downward. Furthermore, since the upper surface of the intermediate header 24 is a conical surface, the metal particles M or the oxides MO dropped on the upper surface of the intermediate header 24 surely fall downward along the surface. Therefore, the oxidation action of the metal particles M can be smoothed and the metal particles can be prevented from being discharged from the exhaust port 27 at the top of the oxidation tower 1. Although not shown, the metal particles discharged from the exhaust port 27 at the top of the oxidation tower 1 are separated by the solid-gas separation device 28 and returned to the oxidation tower 1 when necessary.

  On the other hand, the heat generated by the oxidation of the metal particles M in the oxidation tower 1 is transmitted to the heated fluid flowing in the heat transfer tube 26 through the wall surface of the heat transfer tube 26 and heats the heated fluid. That is, in the chemical loop combustion apparatus according to the present invention, the heat of the metal particles M generated by the oxidation reaction is transferred to the gas (input air), and at the same time, is directly exchanged with the heat transfer tubes 26 located in the metal particles M. Furthermore, the exhaust gas temperature does not increase greatly. Therefore, NOx generation can be further suppressed. Moreover, since the average temperature of the gas (input air) in the oxidation tower 1 is also lowered, thereby reducing the superficial velocity, the cross-sectional area of the oxidation tower 1 can be reduced. As a result, the apparatus can be miniaturized, the surface area per combustion amount can be suppressed, and the heat dissipation loss can be reduced.

  In the above chemical loop combustion apparatus A1a, the region below the intermediate header 24 is a region where metal particles are stored, and the heat transfer tube 26 receives a lot of frictional wear in contact with the metal particles in that region. On the other hand, the region above the intermediate header 24 is a region mainly containing gas, and the frictional wear of the heat transfer tube 26 is small. Therefore, the material of the heat transfer tube 26 is made of a material having excellent wear resistance in the portion located between the lower header 15 and the intermediate header 24 and compared in the portion located between the intermediate header 24 and the upper header 19. And can be made of a material with low wear resistance. Costs can be reduced by using such different materials.

  For example, the heated fluid heated by the heat exchange in the oxidation tower 1 circulates from the upper header 19 through the second fluid pipe 21, the heat load unit 100, and the first fluid pipe 18, and returns to the lower header 15. come. Circulation of the heated fluid to be heated may be reversed.

By contributing to the oxidation reaction in the oxidation tower 1, the input air becomes high-temperature exhaust gas and is discharged from the exhaust port 27. Exhaust gas, depending on the supply amount of air, a high concentration of N ₂ Gasuka containing no O _2, a gas containing residual O ₂ and N _2. After the exhaust gas passing through the solid-gas separation device 28 and the heat exchanger 29 as described above, but stored is sent to N ₂ storage tank tower (not shown), a part of the N ₂ is pressurized by the blower 30 shut-off valve 31 and the pressure regulating valve 32 to be sent from the pipe 14 to the separator gas nozzle 13.

On the other hand, the exhaust gas from the reduction tower 3 consists of CO ₂ and H ₂ O produced by a reduction reaction, and since it is a high-temperature gas, H ₂ O is steam. The exhaust gas from the reduction tower 3 is condensed by an air / water separator 33 in which cooling water circulates and separated into water and a gas containing CO ₂ having a high concentration (90% or more). The obtained CO ₂ gas is stored as it is or as liquefied CO ₂ after further concentration by an appropriate means if necessary. A part of the CO ₂ gas is boosted by the blower 34 when necessary, and sent from the pipe 14 to the separator gas nozzle 13 through the shutoff valve 35 and the pressure regulating valve 32. Therefore, in the chemical loop combustion apparatus A1a of the embodiment shown in FIG. 1, the separator is separated for the purpose of separating the air supplied from the air nozzle 5 and the fuel gas supplied from the fuel nozzle except during the initial operation. The inert gas (N ₂ or CO ₂ ) to be supplied from the gas nozzle 13 can be self-supplied.

  The water generated by the steam separator 33 exchanges heat with the high-temperature exhaust gas from the oxidation tower 1 in the heat exchanger 29 to become steam, and when necessary, the steam passes through the pressure regulating valve 38 and the check valve 39 to become fuel gas. It is mixed. By requiring the supply of water vapor, the reduction reaction can proceed efficiently even when a relatively inexpensive metal particle material such as Fe is used. In addition, the reduction reaction of metal oxide can be efficiently advanced even with a hydrocarbon such as methane having a low reactivity.

  In the above example, the first fluid pipe 18 and the second fluid pipe 21 are described as discontinuous. However, depending on the type and form of the thermal load unit 100, the first fluid pipe 18 is used. A continuous circulation path may be formed between the heat load unit 100 and the second fluid pipe 21. In any case, the same effect can be obtained by configuring the entire pipeline system with the second fluid pipe 21 as the inflow side and the first fluid pipe 18 as the outflow side. I don't need it.

<Second Mode of First Form>
FIG. 2 shows a piping system to which a schematic cross section of a second aspect of the first embodiment of the chemical loop combustion apparatus according to the present invention is attached. The chemical loop combustion apparatus A1b of the second aspect shown in FIG. 2 includes a plurality of (two in the illustrated example) reduction towers 3 and 3 in the oxidation tower 1, and each reduction tower 3 , 3, the air header 4, the air nozzle 5, the fuel nozzle 9, the separate gas nozzle 13, and the like are arranged at the lower end portion of the oxidation tower 1. The configuration is different from the chemical loop combustion apparatus A1a of the embodiment. The configuration of the piping system, the configuration related to the heat transfer tube 26 and the lower header 15, the intermediate header 24, the upper header 19 and the like, and the effects achieved by them are basically the same as in the case of the chemical loop combustion apparatus A1a of the first aspect. Yes, the same reference numerals are given, and the description is omitted.

  In the illustrated example, the two reduction towers 3 and 3 are disposed in the oxidation tower 1 in a posture parallel to the axis of the oxidation tower 1 so as to correspond to the lower end position of each reduction tower 3 and 3. Thus, the air header 4, the air nozzle 5, the fuel nozzle 9, the separate gas nozzle 13, and the like are disposed at the lower end of the oxidation tower 1. The air headers 4 and 4 are supplied with the regulated air from the blower 6, and the fuel nozzles 9 and 9 are regulated through the shut-off valve 10, the pressure regulating valve 11 and the check valve 12. Fuel is delivered. Further, an inert gas that does not contain oxygen is supplied to the separate gas nozzles 13 and 13 through the pipe 14. The exhaust gases discharged from the upper portions of the reduction towers 3 and 3 merge and then flow into the steam / water separator 33 in which cooling water from the outside circulates.

<Third Aspect of First Form>
FIG. 3 shows together with a piping system to which a schematic cross section of a third aspect of the first embodiment of the chemical loop combustion apparatus according to the present invention is attached. The chemical loop combustion apparatus A1c of the third aspect shown in FIG. 3 is basically a chemical loop combustion apparatus of an internal circulation type and a lower supply type, but a reduction tower is not provided inside the oxidation tower. The structure is different from the chemical loop combustion apparatus A1a of the first embodiment shown in FIG. 1 in that the tower and one oxidation tower are provided inside.

  Hereinafter, the configuration of the chemical loop combustion apparatus A1c will be described mainly with respect to the difference in configuration from the chemical loop combustion apparatus A1a according to the first embodiment shown in FIG. The chemical loop combustion apparatus A1c has an outer tower 1a similar to the chemical loop combustion apparatus A1a, and a circular tower 3a is attached in the outer tower 1a with the same central axis. The upper end of the circular column 3a extends through the top plate 2 to the outside of the outer tower 1a, and the lower end reaches the vicinity of the lower end of the outer tower 1a. In the following description, the outer tower 1a is called a reduction tower 1a, and the circular tower body 3a is called an oxidation tower 3a.

  At the center of the lower end of the reduction tower 1a, a circular air header 4 concentric with the oxidation tower 1a is attached. The upper end of the air header 4 is an air nozzle 5. Preferably, the inner diameter of the air nozzle 5 is slightly smaller than the inner diameter of the lower end portion of the oxidation tower 3a. A tower-like fuel nozzle 9 is arranged so as to surround the air header 4, and the regulated fuel is supplied to the fuel nozzle 9 through a shutoff valve 10, a pressure regulating valve 11, and a check valve 12. Is done. A gap is provided between the air header 4 and the fuel nozzle 9 surrounding the outside, and a tower-shaped separate gas nozzle 13 is disposed in the gap. An inert gas not containing oxygen is supplied to the separate gas nozzle 13.

  As shown in FIG. 3, inside the reduction tower 1a, as in the case of the oxidation tower 1 in the chemical loop combustion apparatus A1a of the first aspect, the heat-resistant wall 22, the lower header 15, the intermediate header 24, and the upper header 19 and a heat transfer tube 26 and the like are attached. An exhaust port 27 is provided in the upper part of the reduction tower 1a, and the exhaust gas from the exhaust port 27 is separated from the outside in the same manner as in the chemical loop combustion apparatus A1a of the first mode. Flows into the device 33. Further, the exhaust gas from the oxidation tower 3a is exhausted to the outside air through the solid-gas separation device 28, similarly to the chemical loop combustion device A1a of the first aspect.

  The metal redox reaction in the chemical loop combustion apparatus A1c is described based on FIG. 1 except that the metal reduction reaction proceeds in the outer tower 1a and the metal oxidation reaction proceeds in the circular tower 3a. This is basically the same as the metal redox reaction in the chemical loop combustion apparatus A1a. That is, in the internal space of the reduction tower 1a, the metal oxide particles MO undergo a reduction reaction with the fuel gas supplied from the fuel nozzle 9 to become metal particles M and flow into the oxidation tower 3a. In the process of passing through the oxidation tower 3a, the metal particles M are returned to the metal oxide particles MO through an oxidation reaction with oxygen in the air supplied from the air nozzle 5. The metal oxide particles MO are returned to the reduction tower 1a through the solid-gas separation device 25 attached to the oxidation tower 3a.

  In the chemical loop combustion apparatus A1c, the configuration of the piping system, the configuration related to the heat transfer tube 26 and the lower header 15, the intermediate header 24, the upper header 19, and the like, and the operational effects thereof are basically the chemical loop combustion of the first aspect. This is the same as in the case of the device A1a, and the description is omitted by giving the same reference numerals.

<The 4th mode of the 1st form>
FIG. 4 shows a schematic cross section of a fourth aspect of the first embodiment of the chemical loop combustion apparatus according to the present invention together with a piping system to which a schematic section is attached. The chemical loop combustion apparatus A1d of the fourth aspect shown in FIG. 4 includes a plurality of (two in the illustrated example) oxidation towers 3a, 3a inside the reduction tower 1a, and each oxidation tower 3a. 3a in that the air header 4, the air nozzle 5, the fuel nozzle 9, the separate gas nozzle 13 and the like are arranged at the lower end of the reduction tower 1a. The configuration is different from the chemical loop combustion apparatus A1c of the embodiment. The configuration of the piping system, the configuration related to the heat transfer tube 26 and the lower header 15, the intermediate header 24, the upper header 19 and the like, and the effects achieved by them are basically the same as in the case of the chemical loop combustion apparatus A1c of the third aspect. Yes, the same reference numerals are given, and the description is omitted.

  In the illustrated example, the two oxidation towers 3a, 3a are arranged in the reduction tower 1a in a posture parallel to the axial center line of the reduction tower 1a, and correspond to the lower end positions of the oxidation towers 3a, 3a. Thus, an air header 4, an air nozzle 5, a fuel nozzle 9, a separate gas nozzle 13, and the like are arranged at the lower end of the reduction tower 1a. The air headers 4 and 4 are supplied with the regulated air from the blower 6, and the fuel nozzles 9 and 9 are regulated through the shut-off valve 10, the pressure regulating valve 11 and the check valve 12. Fuel is delivered. Further, an inert gas that does not contain oxygen is supplied to the separate gas nozzles 13 and 13 through the pipe 14.

  As in the case of the chemical loop combustion apparatus A1c, the exhaust gas from the exhaust port 27 formed in the upper part of the reduction tower 1a flows into the steam / water separator 33 in which cooling water from the outside circulates. Further, the exhaust gases from the oxidation towers 3 a and 3 a are merged and then exhausted to the outside air through the solid gas separation device 28.

<Second form>
FIG. 5 shows a schematic cross section of a second embodiment of the chemical loop combustion apparatus according to the present invention together with a piping system. The second form is an external circulation and lower feed type chemical loop combustion apparatus. That is, in the chemical loop combustion apparatus A2 of the second embodiment, the oxidation tower 201 and the reduction tower 203 are separated from each other, the flow path 250 in which the oxidized metal particles MO move and the flow in which the reduced metal particles M move. It is characterized by being connected by a path 260. In the following description, members having substantially the same functions as those in the chemical loop combustion apparatus A1 (A1a to A1d) as the first embodiment are assigned the same reference numerals as the reference numerals of the 200 series, and a specific configuration is provided. Except for different cases, detailed description is omitted.

  In the chemical loop combustion apparatus A2, the oxidation tower 201 and the reduction tower 203 are separated as described above, and both are connected by the metal oxide flow path 250 and the metal particle flow path 260 that are provided with heat insulating means. That is, means such as a lower header 215, an intermediate header 224, an upper header 219, and a heat transfer tube 226, which are means necessary for heat exchange of the fluid to be heated, are present in the oxidation tower 201, but means corresponding to a reduction tower. Does not exist. Therefore, only the air header 204 provided with the air nozzle 205 exists at the bottom of the oxidation tower 201, and the fuel nozzle 9 and the separate gas nozzle 13 in the chemical loop combustion apparatus A1 (A1a to A1d) according to the first embodiment are provided. not exist. Thereby, the diameter of the oxidation tower 201 can be made smaller.

  Further, as described above, the metal oxide particles MO are moved to the reduction tower 203 through the metal oxide flow path 250, and for this reason, the storage upper end position of the metal particles M stored in the oxidation tower 201 is slightly. A flat intermediate header 224 is provided at an upper position, and a first solid-gas separation device 270 is disposed in a central space region of the intermediate header 224. One end of the metal oxide flow path 250 is connected to the solid discharge port side of the first solid-gas separation device 270.

  The reduction tower 203 is in contact with the other end of the metal oxide flow path 250 at an upper position thereof, and includes a second solid-gas separation device 271 between the connection portion and the top plate. One end of a metal particle flow path 260 is connected to a position below the reduction tower 203, and the other end of the metal particle flow path 260 is connected to a lower portion of the oxidation tower 201. A particle reservoir 251 is provided in the middle of the metal oxide channel 250, and a particle reservoir 262 is also provided in the middle of the metal particle channel 260. A fuel nozzle 209 is attached to the bottom surface of the reduction tower 203.

The gas (exhaust gas) after the solid component (mainly metal oxide particles MO) is separated by the first solid-gas separation device 270 attached to the oxidation tower 201 is exhausted from the exhaust port 227. Since solid content is hardly contained, the solid-gas separation device 28 in the chemical loop combustion device A1 (A1a to A1d) which is the first form can be omitted. The solid component (mainly metal oxide particles MO) separated by the first solid-gas separation device 270 flows into the reduction tower 203 through the metal oxide flow path 250 and falls from the fuel nozzle 209 in the process of falling there. The reduced metal particles M are returned to the oxidation tower 201 through the metal particle channel 260 under the reduction action by the fuel gas supplied. The second solid-gas separation device 271 attached to the reduction tower 203 separates the solids (mainly metal oxide particles MO before being subjected to reduction) and returns them to the reduction tower 203, and also gas (mainly CO ₂ and H ₂ O) is discharged from the reduction tower 203 as exhaust gas.

The piping system for the exhaust gas from the oxidation tower 201 and the exhaust gas from the reduction tower 203 is the same as the piping system in the chemical loop combustion apparatus A1 (A1a to A1d) which is the first form. However, the difference is that the inert gas, which is NO ₂ and CO ₂ generated from both exhaust gases, is supplied not as a separate gas nozzle 13 but as a purge gas to the particle reservoirs 251 and 262 described above. By supplying an inert gas as a purge gas to the particle reservoirs 251 and 262, it is possible to reliably prevent air (oxidant) and fuel gas from mixing in the metal oxide channel 250 and the metal particle channel 260. Thus, direct combustion of fuel gas can be reliably avoided. Note that the two particle reservoirs 251 and 262, in particular, the particle reservoir 251 provided in the metal oxide channel 250 can be omitted. Even if omitted, the chemical loop combustion apparatus A2 can be operated.

  Achieved by providing means (lower header 215, intermediate header 224, upper header 219, heat transfer tube 226, etc.) for exchanging heat of oxidation reaction with the fluid to be heated in the oxidation tower 201 in the chemical loop combustion apparatus A2. The operational effect is the same as in the chemical loop combustion apparatus A1 (A1a to A1d) which is the first form, and the description is omitted. Further, the movement of exhaust gas, air, fuel gas, etc. in each pipeline system is the same as in the case of the chemical loop combustion apparatus A1 (A1a to A1d) which is the first form, and the description thereof is omitted.

<Third embodiment>
FIG. 6 shows a schematic cross section of a third embodiment of the chemical loop combustion apparatus according to the present invention together with a piping system attached thereto. The third form is an internal circulation type and top feed type chemical loop combustion apparatus. That is, the chemical loop combustion apparatus A3 of the third form is such that air (oxidant), fuel gas (reducing agent), and separate gas (inert gas) are supplied from the upper part of the oxidation tower 301 and the reduction tower 303. In a certain point, it is different from the chemical loop combustion apparatus A1a of the first embodiment shown in FIG. 1, and is the same as the chemical loop combustion apparatus A1a of the first embodiment except for this point. In the following description, members having substantially the same functions as those in the chemical loop combustion apparatus A1a are denoted by the same reference numerals as the numbers in the 300s, and detailed description is omitted unless specific configurations are different. .

  In the chemical loop combustion apparatus A3, the oxidation tower 301 and the means such as the lower header 315, the intermediate header 324, the upper header 319, and the heat transfer tube 326 which are means necessary for heat exchange of the heated fluid are in the first form. This is substantially the same as the chemical loop combustion apparatus A1a. However, the central portion of the lower header 315 is closed by a concave cone member 360 that is continuous with the upper surface, which is a conical surface 316.

  A reduction tower 303 extending in the axial direction of the oxidation tower 301 is attached to the center of the oxidation tower 301, the upper end side thereof penetrates the top plate 302, and the lower end side reaches the vicinity of the cone member 360 described above. . A fuel gas supply pipe 361 is inserted in the center of the reduction tower 303. The fuel gas supply pipe 361 reaches a position directly above the lower end portion of the reduction tower 303, and the tip portion is a fuel nozzle 309. A required number of separate gas supply pipes 362 are attached along the inner peripheral wall surface of the reduction tower 303, the tip thereof reaches the lower end of the reduction tower 303, and the tip is a separate gas nozzle 313.

  A required number of air supply pipes 363 are attached to the outside in the radial direction of the reduction tower 303 so as to be substantially parallel to the reduction tower 303 and concentrically from the axial line of the reduction tower 303. The upper end side of the air supply pipe 363 passes through the top plate 302, and the lower end side reaches the top surface of the lower header 315 or the vicinity of the cone member 360 described above. The lower end portion of each air supply pipe 363 is an air nozzle 305.

The fuel gas that has been regulated through the shutoff valve 310, the pressure regulating valve 311, and the check valve 312 is supplied to the fuel gas supply pipe 361 and is ejected from the fuel nozzle 309 at the lower end into the reduction tower 303. Air that has been regulated through the blower 306, the flow meter 307, and the pressure regulating valve 308 is supplied to the air supply pipe 363, and is ejected into the oxidation tower 301 from the air nozzle 305 at the lower end. A part of the fuel gas is supplied to any or all of the air supply pipe 363 through the pipe line 364 and the shutoff valve 365 as needed, and is jetted into the oxidation tower 301 from the air nozzle 305 at the lower end. An inert gas such as N ₂ gas or CO ₂ gas is supplied to the separate gas supply pipe 362 through the pipe 314, and the supplied inert gas is supplied from the separate gas nozzle 313 at the tip to the bottom surface (cone member). 360).

  In the above chemical loop combustion apparatus A3, means (such as the lower header 315, the intermediate header 324, the upper header 319, and the heat transfer tube 326) for exchanging heat of the oxidation reaction with the fluid to be heated are provided in the oxidation tower 301. The effect achieved by the above is the same as in the chemical loop combustion apparatus A1a described with reference to FIG. However, in the chemical loop combustion apparatus A3, an air supply pipe 363 that supplies air into the oxidation tower 301, a fuel gas supply pipe 361 that supplies fuel gas into the reduction tower 303, and a separate gas supply pipe 362 are connected to the oxidation tower 301. Since it was attached by dropping from the opening formed in the top plate 302 of the oxidation tower 301, that is, when assembling the chemical loop combustion apparatus A3, lift and assemble those members with a crane or the like. In addition to being easier to manufacture than the chemical loop combustion apparatus A1a shown in FIG. 1, maintenance after operation is extremely easy. In particular, as shown in the drawing, a common mounting substrate 366 is used, and the air supply pipe 363, the fuel gas supply pipe 361, and the separate gas supply pipe 362 are attached thereto, so that they are integrated during assembly or maintenance. It becomes possible to handle it as a product, and workability is further improved.

  In the above chemical loop combustion apparatus A3, the movement of exhaust gas, air, fuel gas, etc. in each pipeline system is substantially the same as in the case of the chemical loop combustion apparatus A1a. However, since the air supply pipe 363, the fuel gas supply pipe 361, and the separate gas supply pipe 362 are attached so as to be inserted from the upper part of the oxidation tower 301 as described above, there is a slight difference in the gas movement. Arise.

That is, after passing through the air supply pipe 363, the air is jetted into the oxidation tower 301 from the air nozzle 305 at the lower end thereof, and contributes to the oxidation reaction with the metal particles M in the process of the air rising. The air after the oxidation reaction, that is, N ₂ rich air, is discharged as exhaust gas from the exhaust port 327 above the oxidation tower 301 in almost the same manner as in the case of the chemical loop combustion apparatus A1a. Further, in the illustrated chemical loop combustion apparatus A3, fuel gas can be supplied to a part of the air supply pipe 363a of the air supply pipe 363 through the shutoff valve 365, and the air supply pipe 363a is connected to the temperature raising burner 363a. Can be used as

During operation, fuel gas is supplied from the upper end of the fuel gas supply pipe 361 and ejected from the fuel nozzle 309 at the lower end. The ejected fuel gas rises together with the metal oxide particles MO in the space region between the inner wall of the reduction tower and the fuel gas supply pipe 361. In the process of rising, the fuel gas contributes to the reduction of the metal oxide particles MO, and the metal oxide particles MO are reduced to the metal particles M. The reduced metal particles M are separated by a solid-gas separation device 325 attached to the reduction tower 303 and returned to the oxidation tower 301. The exhaust gas composed of CO ₂ and water vapor is exhausted from the upper end of the reduction tower 303. The behavior of the exhaust gas thereafter is the same as that of the chemical loop combustion apparatus A1a.

During operation, an inert gas such as CO ₂ or N ₂ is supplied to the separate gas supply pipe 362 from its upper end, and is jetted into the oxidation tower 301 from the separate gas nozzle 313. The inert gas that is ejected prevents the air ejected from the air nozzle 305 from mixing with the fuel gas ejected from the fuel nozzle 309 at the lower end of the fuel gas supply pipe 361 and prevents direct combustion of the fuel gas. it can. This is also the same as in the case of the chemical loop combustion apparatus A1a.

  Further, by attaching a cone member 360 having a smooth conical surface or a parabolic surface to a portion facing the lower end of the reduction tower 303 at the bottom of the oxidation tower 301, the movement of the metal oxide particles MO or the metal particles M can be performed. The metal oxide particles MO or metal particles M can flow smoothly from the bottom of the oxidation tower 301 into the reduction tower 303.

  Although not shown, the third embodiment of the chemical loop combustion apparatus of the internal circulation type and the upper supply type chemical loop combustion apparatus also includes a plurality of reduction towers 303 in the oxidation tower 301 as a modified mode. A mode of arrangement (a mode corresponding to the chemical loop combustion apparatus A1b shown in FIG. 2), a mode of arranging one oxidation tower in the reduction tower (a mode corresponding to the chemical loop combustion apparatus A1c shown in FIG. 3), It is not necessary to explain that a plurality of oxidation towers may be arranged in the reduction tower (an aspect corresponding to the chemical loop combustion apparatus A1d shown in FIG. 4).

<4th form>
FIG. 7 shows a schematic cross section of a fourth embodiment of the chemical loop combustion apparatus according to the present invention together with a piping system. The fourth embodiment is an external circulation type and top feed type chemical loop combustion apparatus. That is, the fourth form of the chemical loop combustion apparatus A4 is such that air (oxidant), fuel gas (reducing agent), and separate gas (inert gas) are supplied from above the oxidation tower 401 and the reduction tower 403. In a certain point, it is the same as the chemical loop combustion apparatus A3 which is the third embodiment, and the oxidation tower 401 and the reduction tower 403 are separated from each other, the flow path 450 in which the oxidized metal particles MO move and the reduced metal particles. It is different from the chemical loop combustion apparatus A3 which is the third embodiment in that M is connected by a flow path 460 through which the M moves. The structure in which the oxidation tower 401 and the reduction tower 403 are separated is substantially the same as the chemical loop combustion apparatus A2 that is the second embodiment shown in FIG. In the following description, members having substantially the same function as those in the chemical loop combustion apparatus A3 that is the third embodiment are denoted by the same reference numerals as the 400s, and the specific configuration is different. Detailed description is omitted.

  Similarly to the chemical loop combustion apparatus A2, the chemical loop combustion apparatus A4 includes a lower header 415, an intermediate header 424, an upper header 419, and a heat transfer tube 426, which are means necessary for heat exchange of the heated fluid. However, there is no means corresponding to the reduction tower. The central portion of the lower header 415 is closed by a concave cone member 460 that is continuous with the upper surface, which is a conical surface 416.

  A required number of air supply pipes 463 extending in the axial direction of the oxidation tower 401 are inserted in the central part of the oxidation tower 401, and the lower end thereof reaches the vicinity of the bottom surface of the oxidation tower 401. The lower end tip of the air supply pipe 463 is an air nozzle 405. Further, as described above, the metal oxide particles MO are moved to the reduction tower 403 through the metal oxide flow channel 450, and therefore, slightly above the storage upper end position of the metal particles M stored in the oxidation tower 401. A flat intermediate header 424 is provided at a position, and a first solid-gas separation device 470 is disposed in a central space region of the intermediate header 424. One end of the metal oxide flow channel 450 is connected to the solid discharge port side of the first solid-gas separation device 470. Further, the air supply pipe 463 described above passes through the first solid-gas separation device 470.

  A fuel gas supply pipe 461 is inserted into the reduction tower 403 so as to pass through the top surface thereof in parallel with the axial line direction of the reduction tower 403, and the lower end thereof reaches the vicinity of the bottom surface of the reduction tower 403. The fuel nozzle 409 is used. The reduction tower 403 is in contact with the other end of the metal oxide flow channel 450 at an upper position thereof, and includes a second solid-gas separation device 471 between the connection portion and the top plate. The fuel gas supply pipe 461 passes through the second solid-gas separation device 471. One end of a metal particle flow path 460 is connected to a position below the reduction tower 403, and the other end of the metal particle flow path 460 is connected to a lower portion of the oxidation tower 401. A particle reservoir 451 is provided in the middle of the metal oxide channel 450, and a particle reservoir 462 is also provided in the middle of the metal particle channel 460.

  In the above chemical loop combustion apparatus A4, means for exchanging heat of oxidation reaction with the fluid to be heated (lower header 415, intermediate header 424, upper header 419, heat transfer tube 426, etc.) is provided in the oxidation tower 401. 1 is the same as that in the chemical loop combustion apparatus A1a described with reference to FIG. 1, and the effect obtained by attaching the air supply pipe 463 from above the oxidation tower 401 is as shown in FIG. This is the same as in the chemical loop combustion apparatus A3 described based on the above. Further, by allowing fuel gas to be supplied to a part of the plurality of air supply pipes 463 through the shutoff valve 465, the air supply pipe 463a can be used as the temperature raising burner 463a. Is similar to the chemical loop combustion apparatus A3 described with reference to FIG.

In the chemical loop combustion apparatus A4, the air supplied from above passes through the air supply pipe 463, and then is ejected from the air nozzle 405 at the lower end portion into the oxidation tower 401. It contributes to the oxidation reaction. The air after the oxidation reaction, that is, the N ₂ rich air is discharged as exhaust gas from the exhaust port 427 at the top of the oxidation tower 401 through the first solid-gas separation device 470 as in the case of the chemical loop combustion device A3. The same.

The solid (mainly metal oxide particles MO) separated by the first solid-gas separation device 470 moves to the reduction tower 403 through the metal oxide flow channel 450, where it undergoes a reduction action to become metal particles M, and after reduction. The metal particles M are returned to the oxidation tower 401 through the metal particle flow path 460, and the second solid-gas separation device 471 attached to the reduction tower 403 has a solid content (mainly oxidation before being subjected to reduction). The metal particles MO) are separated and returned into the reduction tower 403, and the gases (mainly CO ₂ and H ₂ O) are discharged from the reduction tower 403 as exhaust gas in the second chemical loop combustion shown in FIG. Same as device A2. However, in the fourth chemical loop combustion apparatus A4, the fuel gas supply pipe 461 is attached to the inside of the reduction tower 403 from above the reduction tower 403, so that the assembly and maintenance of the reduction tower 403 become extremely easy.

  The movement of exhaust gas, air, fuel gas, etc. in the other pipe systems is the same as in the case of the chemical loop combustion apparatus A2, and the description thereof is omitted.

In any of the above-described chemical loop combustion apparatuses, as described above, high-concentration CO ₂ can be separated from the exhaust gas. If necessary, CO ₂ recovered at a concentration of 90% or more is further concentrated by using, for example, the PSA method or the like according to the intended use, whereby a 99.999% concentration of CO ₂ is obtained.

  In addition, in the operation of the chemical loop combustion apparatus according to the present invention, in order to keep the metal particles (M) and the metal oxide particles (MO) of the entire system within a certain ratio range, not only the instantaneous values of fuel and oxidant By managing the integrated input amount, it is possible to determine whether the entire system has approached the oxidation side or the reduction side from the start of operation, and can provide feedback. Further, in order to determine whether or not the fuel and the oxidant are properly reacting via the metal, it is recommended to control the “effective oxygen utilization rate” shown below at around 1.0.

Effective oxygen utilization rate = (External oxygen input-Oxygen amount out of system) / (Theoretical oxygen amount of fuel)
Furthermore, in the chemical loop combustion apparatus according to the present invention, a pressure gauge can be installed in the vicinity of the outlets of the oxidation tower and the reduction tower. When it is desired to extract CO ₂ at a high concentration from reduction or the like, the exhaust blower is controlled by an inverter so that the pressure on the reduction tower side is slightly higher than the pressure in the oxidation tower.

  Further, two thermocouples can be inserted into the oxidation tower in order to confirm that the reaction in the apparatus continues. One part is inserted below the particle surface below the solid-gas separator, and the other is installed at the top of the solid-gas separator. Then, the temperature inside the metal particles is kept above the reaction temperature of the reducing agent (for example, 760 ° C. in the case of natural gas). If it cannot be maintained, the fuel gas supply is shut off.

Further, in any of the above chemical loop combustion apparatuses, as shown in the drawing, water vapor obtained from the water generated by the steam separator 33 is supplied to the fuel nozzle 9 through the pressure regulating valve 38 and the check valve 39. It was to be supplied into the road, a gas containing water vapor and CO ₂ is produced within the device (e.g., exhaust gas from the reducing tower 3) to the gas containing the reducing agent supplied to the reduction column (fuel gas) Even if it is added, the same effect can be obtained.

A1 ... Chemical loop combustion device,
1 ... oxidation tower,
3 ... reduction tower,
4 ... Air header,
5 ... Air nozzle,
9 ... Fuel nozzle,
13 ... Separate gas nozzle,
15 ... Lower header,
18 ... first fluid piping,
19 ... Upper header,
21 ... second fluid piping,
22 ... heat resistant wall,
24 ... Intermediate header,
25. Solid-gas separation device,
26 ... Heat transfer tube,
27 ... The exhaust port at the top of the oxidation tower,
28 ... Solid-gas separation device,
29 ... heat exchanger,
33. Steam-water separator,
100 ... heat load part,
M ... metal particles,
MO: Metal oxide particles.

Claims (4)

An oxidation tower in which metal particles react with an oxidant to generate oxides of the metal particles, and a reduction tower in which oxides of metal particles generated in the oxidation towers react with a reducing agent to be reduced to the metal particles A chemical loop combustion apparatus in which the metal particles are circulated between the oxidation tower and the reduction tower while undergoing oxidation and reduction,
One or more of the reduction towers are incorporated in the oxidation tower,
A chemical heat transfer tube is disposed in the oxidation tower or the reduction tower of the chemical loop combustion apparatus to contact the metal particles or the oxide thereof and transfer reaction heat to the heated fluid. Loop combustion device. An oxidation tower in which metal particles react with an oxidant to generate oxides of the metal particles, and a reduction tower in which oxides of metal particles generated in the oxidation towers react with a reducing agent to be reduced to the metal particles A chemical loop combustion apparatus in which the metal particles are circulated between the oxidation tower and the reduction tower while undergoing oxidation and reduction,
One or more oxidation towers are incorporated in the reduction tower,
A chemical heat transfer tube is disposed in the oxidation tower or the reduction tower of the chemical loop combustion apparatus to contact the metal particles or the oxide thereof and transfer reaction heat to the heated fluid. Loop combustion device. 3. The chemical loop combustion apparatus according to claim 1, wherein headers are provided near an upper portion and a lower portion of the oxidation tower or the reduction tower, and the heat transfer tubes are provided at the upper header and the lower header. A chemical loop combustion apparatus, wherein the chemical loop combustion apparatus is arranged to communicate with each other. 4. The chemical loop combustion apparatus according to claim 3 , wherein the oxidation tower or the reduction tower further includes an intermediate header between the vicinity of the upper part and the vicinity of the lower part, and the heat transfer tube includes the upper header and the intermediate part. A chemical loop combustion apparatus, wherein the chemical loop combustion apparatus is disposed so as to communicate with a header and the lower header.

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