JP2012172891A - Chemical loop combustion equipment in which oxidizing agent and/or reducing agent are supplied from top face side of reaction tower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide chemical loop combustion equipment A1 which enhances equipment maintenability and further evades a reverse flow of metal particles from a nozzle, thereby greatly enhancing workability in actual use when the equipment is actually operated as an industrial facility.SOLUTION: In the chemical loop combustion equipment A1, an oxidizing agent supply pipe 63 for supplying an oxidizing agent to the inside of an oxidation tower 1 is inserted from the top face 2 side of the oxidation tower 1 to the base side, and a reducing agent supply pipe 61 for supplying a reducing agent to the inside of a reduction tower 3 is inserted from the top face side of the reduction tower 3 to the base side. The oxidizing agent supply pipe 63 and the reducing agent supply pipe 61 are attached to a common attaching base 66, thereby simplifying the attachment and detachment thereof.

Description

  The present invention relates to a chemical loop combustion apparatus in which an oxidizing agent and / or a reducing agent are supplied from the top side of a reaction tower.

  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.

  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 in an oxidation tower, and an oxidation tower and a reduction tower are separated. Has proposed a so-called external circulation system in which a channel of oxidized metal particles and a channel of reduced metal particles are connected. The supply of the oxidizing agent into the oxidation tower and the supply of the reducing agent into the reduction tower are carried out by jetting upward from the oxidizing agent nozzle and the reducing agent nozzle provided at the bottom of the oxidation tower in the form of the internal circulation system. In the external circulation system, the oxidant is jetted upward from the oxidant nozzle provided at the bottom of the oxidation tower, and the reducing agent is jetted upward from the reducing agent nozzle provided at the bottom of the reduction tower. ing.

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, OhbaT ENERGY CONVERSION AND MANAGEMENT 2002, 43,9-12,1469-1478

  As described in Non-Patent Document 1 described above, the currently proposed chemical loop combustion apparatus is configured so that the fuel and the oxidant as the reducing agent are supplied to the reduction tower and the oxidation tower from below. Therefore, when actually used as normal industrial equipment, the maintainability of the apparatus is very poor. In addition, when fuel (reducing agent) or air (oxidant) is used with a nozzle from the bottom, the metal particles used for chemical loop combustion are fine particles having a diameter of about 100 μm as an example when the supply of gas is stopped. Because of this, the metal particles flow back from the nozzle facing upward. When the chemical loop combustion apparatus is actually used as industrial equipment, the above is a disadvantage that cannot be ignored.

  The present invention has been made in view of the above circumstances, and even when actually operating as industrial equipment, it improves the maintainability of the apparatus, and avoids backflow of metal particles from the nozzle. It is an object of the present invention to provide a chemical loop combustion apparatus in which oxidant and / or reducing agent is supplied from the top surface side of the reaction tower, which can greatly improve the operability as an actual machine.

  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 loop combustion apparatus comprising a reduction tower that is reduced to the metal particles as a reaction tower, wherein the metal particles are circulated between the oxidation tower and the reduction tower while undergoing oxidation and reduction. The oxidizing agent supply pipe for supplying the oxidizing agent into the oxidation tower and / or the reducing agent supply pipe for supplying the reducing agent into the reduction tower are arranged from the top side to the bottom side of the respective reaction towers. It is inserted in the direction.

  In the chemical loop combustion apparatus according to the present invention, both an oxidant supply pipe for supplying an oxidant (for example, air) into the oxidation tower and a reducing agent supply pipe for supplying a reducing agent (for example, a fuel gas such as methane) into the reduction tower. Or either one is a structure inserted from the top surface side to the bottom surface side of each reaction tower, and when assembling the chemical loop combustion apparatus, lift and assemble those members with a crane or the like It can be removed. Therefore, in addition to facilitating the production of the chemical loop combustion apparatus, maintenance after operation becomes extremely easy. Furthermore, the oxidizing agent supply pipe and / or the reducing agent supply pipe inserted from the top surface side to the bottom surface side of the reaction tower are attached with the opening end of the lower end portion directed downward, so that the oxidizing agent Alternatively, when the supply of the reducing agent is stopped, the metal particles used for the chemical loop combustion do not flow backward in the inside thereof. Even if it is compared with the chemical loop combustion apparatus of the form described in the nonpatent literature 1, the maintainability and operativity improve.

  In the chemical loop combustion apparatus according to the present invention, one or more reduction towers may be incorporated in the oxidation tower. In that case, it is preferable that the bottom surface of the oxidation tower has a mortar-like surface curved downward from the viewpoint of smooth movement of the metal particles.

  In the chemical loop combustion apparatus according to the present invention, one or more oxidation towers may be incorporated in the reduction tower. Also in this case, it is preferable from the viewpoint of smooth movement of the metal particles that the bottom surface of the reduction tower has a mortar-like surface curved downward.

  In a preferred form of the chemical loop combustion apparatus according to the present invention, the oxidation tower includes a plurality of oxidant supply pipes, and a part of the oxidant supply pipes can selectively supply an oxidant and a reducing agent. It is characterized by. In this mode, at the start of operation, a part of the reducing agent (fuel gas) in the plurality of oxidant supply pipes is supplied, and the oxidant (air) is supplied to the other oxidant supply pipes. This makes it possible to cause direct combustion of the oxidizing agent (air) and the reducing agent (fuel gas), and has the advantage that the heat can be used for preheating the metal particles at the start of operation. When the required preheating is completed, the supply of the reducing agent is stopped and switched to the supply of the oxidizing agent.

  The overall shape of the chemical loop combustion apparatus according to the present invention may be a so-called internal circulation type chemical loop combustion apparatus in which an oxidation tower and a reduction tower are integrated, and the oxidation tower and the reduction tower are separated from each other. May be a so-called external circulation type chemical loop combustion apparatus connected by a flow path of oxidized metal particles and a flow path of reduced metal particles.

  In a preferred embodiment of the chemical loop combustion apparatus according to the present invention, a heat transfer tube is disposed in the oxidation tower or reduction tower to contact the metal particles or oxide thereof and transfer reaction heat to the fluid to be heated. It is characterized by.

In the chemical loop combustion apparatus of the above aspect, for example, in a mode in which the heat transfer tube is arranged in the oxidation tower, heat generated by the oxidation reaction of the metal particles is exchanged with the heated fluid flowing in the heat transfer pipe. Therefore, the temperature of the input air (exhaust gas), which is mainly N ₂ , discharged from the oxidation tower does not increase greatly, and the average temperature of the gas 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. Furthermore, the above chemical loop combustion apparatus can be miniaturized as described above, and the heat of the heated fluid flowing in the heat transfer tube can also be used as a heat source for on-site steam utilization equipment or industrial furnaces. It becomes. 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.

  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.

  According to the present invention, even when the system is actually operated as an industrial facility, the maintainability of the apparatus is good, and the operability as an actual machine is greatly improved by avoiding the backflow of metal particles from the nozzle. In addition, a chemical loop combustion apparatus in which an oxidizing agent and / or a reducing agent is supplied from the top surface side of the reaction tower can be obtained.

The figure shown with the piping system which attaches the internal circulation 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 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 apparatus of the form which is the internal circulation type which is the 3rd form of the chemical loop combustion apparatus by this invention, and was provided with the heat exchanger tube. The figure shown with the piping system which attaches the apparatus of the form which is the external circulation type which is the 4th form of the chemical loop combustion apparatus by this invention, and was equipped with the heat exchanger tube. The figure shown with the piping system which attaches the 1st modification of the chemical loop combustion apparatus which is a 3rd form. The figure shown with the piping system which attaches the 2nd modification of the chemical loop combustion apparatus which is a 3rd form. The figure shown with the piping system which attaches the 3rd modification of the chemical loop combustion apparatus which is a 3rd form. The figure shown with the piping system which attaches the 4th modification of the chemical loop combustion apparatus which is a 3rd form. The figure shown with the piping system which attaches the 5th modification of the chemical loop combustion apparatus which is a 3rd form. The figure shown with the piping system which attaches the 6th modification of the chemical loop combustion apparatus which is a 3rd form. The figure shown with the piping system which attaches the 7th modification of the chemical loop combustion apparatus which is a 3rd form. The figure shown with the piping system which attaches the 1st modification of the chemical loop combustion apparatus which is a 4th form. The figure shown with the piping system which attaches the 2nd modification of the chemical loop combustion apparatus which is a 4th form.

Hereinafter, several forms of a chemical loop combustion apparatus according to the present invention will be described with reference to the drawings.
<First embodiment>
FIG. 1 shows a piping system to which an internal circulation type apparatus as a first form of a chemical loop combustion apparatus according to the present invention is attached. The illustrated chemical loop combustion apparatus A1 has a circular tower-shaped outer tower 1 made of a heat-resistant material such as a steel plate, and the top surface of the outer tower 1 is also made of a heat-resistant material such as a steel plate. Closed at 2. 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.

  The bottom surface of the oxidation tower 1 is closed by a bottom member made of a heat-resistant material, and the upper surface 16 of the heat-resistant bottom portion has a mortar-like surface curved downward. Specific examples of the mortar-shaped surface include a conical surface or a parabolic surface. A heat-resistant material such as a heat-resistant roof tile or a heat-resistant ceramic fiber is attached to the inner peripheral surface and the top surface of the oxidation tower 1. A region of about 2/3 from the bottom on the inner peripheral surface of the oxidation tower 1 is a thick region 22a, so that the horizontal cross-sectional area is narrower than the region above it. The upper end surface of the thick region 22a is a conical wall 22b, and a solid-gas separation device 25 is attached to the portion of the reduction tower 3 in the vicinity of the upper end surface of the thick region 22a.

  A fuel gas supply pipe 61 is inserted in the center of the reduction tower 3. The fuel gas supply pipe 61 reaches a position directly above the lower end portion of the reduction tower 3, and the tip portion is a fuel nozzle 9. A required number of separate gas supply pipes 62 are attached along the inner peripheral wall surface of the reduction tower 3, the tip of which reaches the lower end of the reduction tower 3, and the tip is a separate gas nozzle 13.

  A required number of air supply pipes 63 are attached to the outside in the radial direction of the reduction tower 3 so as to be substantially parallel to the reduction tower 3 and concentrically from the axial center line of the reduction tower 3. The upper end side of the air supply pipe 63 passes through the top plate 2, and the lower end side reaches the vicinity of the upper surface 16 of the bottom member attached to the bottom of the oxidation tower 1. The lower end portion of each air supply pipe 63 is an air nozzle 5.

The fuel gas supply pipe 61 is supplied with regulated fuel such as methane through the shutoff valve 10, the pressure regulating valve 11 and the check valve 12, and is reduced from the fuel nozzle 9 which is the lower end opening of the reduction tower 3. It spouts into the tower 3. As will be described later, this fuel functions as a reducing agent. The air supply pipe 63 is supplied with pressure-adjusted air (which may be air at ambient temperature) through the blower 6, the flow meter 7, and the pressure control valve 8, and is ejected into the oxidation tower 1 from the air nozzle 5 at the lower end. To do. A part of the fuel gas described above passes through the pipe 64 and the shutoff valve 65 and is supplied to any of the air supply pipes 63 when necessary, and is jetted into the oxidation tower 1 from the air nozzle 5 at the lower end. An inert gas such as N ₂ gas or CO ₂ gas is supplied to the separate gas supply pipe 62 through the pipe 14. The supplied inert gas is ejected from the separate gas nozzle 13 at the tip toward the bottom surface of the oxidation tower 1.

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 internal circulation type chemical loop combustion apparatus A1 according to the first embodiment. However, in order to perform more efficient operation, the chemical loop combustion apparatus A1 is further configured as follows. The piping system is provided.

The exhaust gas from the exhaust port 27 passes through the solid-gas separator 28 and then passes through the heat exchangers 29 and 29a. The N2 gas that has passed through the heat exchangers 29 and 29a 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 separate gas supply pipe 62 through the shutoff 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 separate gas supply pipe 62 through the shutoff valve 35 and the pressure regulating valve 32.

  The water generated in the steam separator 33 reaches the heat exchanger 29a 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. The water vapor is supplied into the fuel gas supply pipe to the fuel gas supply pipe 61 as water vapor.

The operation of the chemical loop combustion apparatus A1 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 ₃ O ₄ , Fe ₂ O ₃ ). After the filling, fuel gas is supplied to a part of the air supply pipe 63a of the air supply pipe 63 through the shut-off valve 65, and air as an oxidant is supplied to the other air supply pipe 63, so And air are burned directly. The metal particles M are preheated to about 600 ° C., which is a temperature at which the oxidation reaction is possible, by the combustion heat. In this state, the air supply pipe 63a functions as a temperature raising burner 63a for preheating the metal particles. The preheating of the metal particles can also be performed with an electric heater attached to the oxidation tower 1 or the like.

After the preheating is completed, the pressure regulating valve is operated to supply a predetermined amount of air (which may be air having an environmental temperature) to all the air supply pipes 63 and ejected from the air nozzle 5 into the oxidation tower 1. Let Further, a predetermined amount of fuel gas such as methane that functions as a reducing agent is supplied to the fuel gas supply pipe 61 and ejected from the fuel nozzle 9. Further, an inert gas such as N ₂ or CO ₂ is ejected from the separate 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.

The air jetted into the oxidation tower 1 from the air nozzle 5 contributes to the oxidation reaction with the metal particles M in the process of rising. The air heated by the oxidation reaction heat, that is, N ₂ -rich high-temperature air is discharged as exhaust gas from the exhaust port 27 at the top of the oxidation tower 1 as described above, and exchanges heat with the fluid to be heated in the heat exchanger 29. I do. The heated fluid heated by heat exchange is sent to a heat load section (not shown) (for example, a steam utilization facility).

The fuel gas from the fuel nozzle 9 flows into the reduction tower 3, but during operation, an inert gas such as CO ₂ or N ₂ is supplied from the upper end of the separate gas supply pipe 62, and the oxidation tower 1 is supplied from the separate gas nozzle 13. Erupts inside. Mixing of the air ejected from the air nozzle 5 and the fuel gas ejected from the fuel nozzle 9 at the lower end of the fuel gas supply pipe 61 is avoided and the direct combustion of the fuel gas is prevented by the ejected inert gas. Is done.

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. 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 ₂ O ₃ , the metal oxide particle MO is Fe ₃ O ₄ 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 bottom of the oxidation tower 1 has a conical surface that becomes lower 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 smooth. proceed. The solid component and the 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 is further raised and exhausted from the upper part of the reduction tower 3. The 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 above chemical loop combustion apparatus A1, since the thick region 22a is formed on a part of the inner wall surface of the oxidation tower 1, the horizontal cross-sectional area in the region above the thick region 22a region as described above. The metal particles M or their oxides MO that have soared into the upper space have a low superficial velocity and are likely to fall downward. Furthermore, since the upper end surface of the thick region 22a is a conical wall 22b, the metal particle M or its oxide MO that has fallen there reliably falls downward along that 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. 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.

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 as described above, high concentrations of N ₂ Gasuka containing no O _2, a gas containing residual O ₂ and N _2. As described above, a part of the N ₂ in the exhaust gas is increased in pressure by the blower 30 and sent from the pipe 11 to the separate gas nozzle 13 through the shutoff valve 31 and the pressure regulating valve 32.

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 11 to the separate gas supply pipe 62 through the shutoff valve 35 and the pressure regulating valve 32. Therefore, in the chemical loop combustion apparatus A1 of the form shown in the figure, except for the initial operation time, from the separate gas nozzle 13 for the purpose of separating the air supplied from the air nozzle 5 and the fuel gas supplied from the fuel nozzle. It becomes possible to supply the inert gas (NO ₂ or CO ₂ ) to be 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 29a 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, it is possible to efficiently proceed the reduction reaction even with a hydrocarbon such as methane having a low reactivity.

  In the above chemical loop combustion apparatus A1, the air supply pipe 63 for supplying air into the oxidation tower 1, the fuel gas supply pipe 61 for supplying fuel gas into the reduction tower 3 and the separate gas supply pipe 13 are connected to the oxidation tower 1 Since it is attached so as to drop from an opening formed on the top surface of the oxidation tower 1, that is, when assembling the chemical loop combustion apparatus A1, it is possible to lift and assemble those members with a crane or the like. It becomes possible and manufacture becomes easy. In addition, maintenance after operation is extremely easy. In particular, as shown in the drawing, a common mounting substrate 66 is used, and the air supply pipe 63, the fuel gas supply pipe 61, and the separate gas supply pipe 13 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.

<Second form>
FIG. 2 shows a chemical loop combustion apparatus according to the present invention together with a piping system provided with a schematic cross section of a second embodiment of the chemical loop combustion apparatus. In the chemical loop combustion apparatus A2 of the second embodiment, the oxidation tower 201 and the reduction tower 203 are separated, and both of them are a flow path 250 in which the oxidized metal particles MO move and a flow path 260 in which the reduced metal particles M move. Are different from the chemical loop combustion apparatus A1 of the first embodiment shown in FIG. Other configurations are substantially the same as those of the chemical loop combustion apparatus A1, and in the following description, members having substantially the same functions as those in the chemical loop combustion apparatus A1 as the first embodiment are denoted by the same reference numerals. A detailed description will be omitted except for a case where the reference numeral is assigned as a reference numeral and the specific configuration is different.

  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, there is no means corresponding to the reduction tower in the oxidation tower 201. Therefore, the diameter of the oxidation tower 201 can be made smaller.

  A required number of air supply pipes 263 extending in the axial direction of the oxidation tower 201 are inserted in the central portion of the oxidation tower 201, and the lower end thereof reaches the vicinity of the bottom surface of the oxidation tower 201. The lower end tip of the air supply pipe 263 is an air nozzle 205.

  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 plate-like levitation prevention plate 267 is disposed at an upper position, and a first solid-gas separation device 270 is disposed at the center thereof. 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. In addition, a heat-resistant wall 222 is attached to the inner peripheral surface of the oxidation tower 201 so that the upper horizontal cross-sectional area is larger than the lower horizontal cross-sectional area below the levitation prevention plate 267. The structure of the bottom of the oxidation tower 201 is the same as that of the oxidation tower 1 of the chemical loop combustion apparatus A1 shown in FIG. Further, the air supply pipe 263 described above passes through the first solid-gas separation device 270.

  A fuel gas supply pipe 261 is inserted into the reduction tower 203 in parallel with the axial direction of the reduction tower 203 so as to pass through its top surface, and its lower end reaches the vicinity of the bottom surface of the reduction tower 203. Thus, the fuel nozzle 209 is used. 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.

  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 almost no solid content is contained, the solid-gas separation device 28 in the chemical loop combustion apparatus A1 shown in FIG. 1 can be omitted.

In the chemical loop combustion apparatus A2, the air supplied from above passes through the air supply pipe 263, and then is ejected from the air nozzle 205 at the lower end thereof into the oxidation tower 201. It contributes to the oxidation reaction. The air after the oxidation reaction, that is, N ₂ rich air is discharged as high-temperature exhaust gas from the exhaust port 227 at the top of the oxidation tower 201 through the first solid-gas separation device 270. As in the case of the chemical loop combustion apparatus A1, the high-temperature exhaust gas exchanges heat with the heated fluid in the heat exchanger 229.

The solid (mainly metal oxide particles MO) separated by the first solid-gas separation device 270 moves to the reduction tower 203 through the metal oxide flow path 250, where it undergoes a reduction action to become metal particles M, after reduction. The metal particles M are returned to the oxidation tower 201 through the metal particle channel 260. The second solid-gas separation device 271 attached to the reduction tower 203 separates and reduces the solid content (mainly metal oxide particles MO before being reduced) in the exhaust gas flowing in from the metal oxide flow channel 250. While returning to the inside of the tower 23, gas (mainly CO ₂ and H ₂ O) is discharged from the reduction tower 203 as exhaust gas. In the chemical loop combustion apparatus A2 of the second embodiment, the fuel gas supply pipe 261 is attached in the reduction tower 203 from the top surface of the reduction tower 203, and the assembly and maintenance of the reduction tower 203 become extremely easy.

The piping system for the exhaust gas from the oxidation tower 201 and the exhaust gas from the reduction tower 203 is substantially the same as the piping system in the chemical loop combustion apparatus A1 shown in FIG. However, as shown in the pipeline diagram of FIG. ₂ , 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 above-described particle reservoirs 251 and 262. Is different. 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.

<Third embodiment>
FIG. 3 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. In the chemical loop combustion apparatus A3 of the third embodiment, a heat transfer tube 326 is disposed in the oxidation tower 301, and the heat between the oxidation reaction heat generated in the oxidation tower 301 and the fluid to be heated flowing in the heat transfer pipe 326 is obtained. This is different from the chemical loop combustion apparatus A1 shown in FIG. 1 in that the exchange is performed in the oxidation tower 301. The other configurations are the same as those of the chemical loop combustion apparatus A1 according to the first embodiment, and in the following description, members having substantially the same functions as those of the chemical loop combustion apparatus A1 according to the first embodiment are the same. The reference numerals are assigned as the reference numerals in the 300s, and detailed description is omitted unless the specific configuration is different.

  In the chemical loop combustion apparatus A3, a circular lower header 315 is attached to the bottom of the oxidation tower 301. The bottom surface of the lower header 315 is a horizontal plane, but the upper surface is a conical surface 316, and the lower end of the conical surface is substantially flush with the air nozzle 305. The outer peripheral surface of the lower header 315 is in contact with the inner peripheral surface of the oxidation tower 301, and a first fluid pipe 318 through which a fluid to be heated flows through a hole 317 formed in the wall surface of the oxidation tower 301 is an outer peripheral surface of the lower header 314. Connected to. 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 tower-like upper header 319 is attached above the oxidation tower 301 so as to contact the top plate 302. The inner diameter and outer diameter of the upper header 319 are substantially the same as those of the lower header 315. A second fluid pipe 321 for a fluid to be heated is connected to the upper header 319 through a hole 320 formed in the top plate 302 of the oxidation tower 301. In this example, the second fluid pipe 221 communicates with a heat load 300 such as an on-site steam utilization facility or an industrial furnace.

  A heat-resistant wall 322 having an appropriate thickness made of a heat-resistant material such as a heat-resistant tile or a heat-resistant ceramic fiber is formed from the upper conical surface 316 of the lower header 315 to an appropriate upper position along the inner wall of the oxidation tower 301. The upper end surface of the heat-resistant wall 322 is a conical wall 323. An intermediate header 324 having a swash plate shape as a whole is attached so that the lower end surface is aligned with the upper end conical wall 323 of the heat-resistant wall 322. The inner and outer diameters of the intermediate header 324 are the same as those of the lower header 315 and the inner diameter. And is almost equal to the outer diameter. A solid-gas separation device 325 is attached to the reduction tower 303 at a position slightly above the position where the intermediate header 324 is attached.

  A plurality of heat transfer tubes 326 are attached in parallel to the central axis of the oxidation tower 301 so that the internal spaces of the lower header 315, the intermediate header 324, and the upper header 319 communicate with each other. In the drawing, the plurality of heat transfer tubes 326 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 326 in the oxidation tower 301 is arranged. Is optional, and may be appropriately arranged on condition that the flow of the metal particles accommodated in the oxidation tower 301 is not hindered, as will be described later.

  The lower header 315, the intermediate header 324, and the upper header 319 are made of a material having excellent heat resistance. In particular, the heat transfer tube 326 is made of a material and shape having excellent heat resistance and thermal conductivity. Further, as will be described later, the heat transfer tube 326 is made of a different material for a portion located between the lower header 315 and the middle header 324 and a portion located between the middle header 324 and the upper header 319. Is desirable.

  The piping system for the exhaust gas from the oxidation tower 301 and the exhaust gas from the reduction tower 303 is substantially the same as the piping system in the chemical loop combustion apparatus A1 shown in FIG.

  In the above chemical loop combustion apparatus A3, during operation, the lower header 315, the intermediate header 324 and the upper header 318, all the heat transfer tubes 326, and the first fluid piping 318 and the second fluid piping 321 are, for example, water. Fill with heated solution. Thereafter, the oxidation reaction in the oxidation tower 301 and the reduction reaction in the reduction tower 303 are advanced in the same manner as in the chemical loop combustion apparatus A1.

  In the above chemical loop combustion apparatus A3, the upper surface 316 of the lower header 315 is a conical surface that becomes lower toward the center, and the surface of the central portion of the lower header 315 is continuous with the upper surface 316. Since the cone member 360 which is a smooth conical surface or a parabolic surface is attached, the movement of the metal oxide particles MO or the metal particles M in the oxidation tower 301 can be facilitated, and the reduction tower is started from the bottom of the oxidation tower 301. The metal oxide particles MO or the metal particles M flow into the inside 303.

  In the oxidation tower 301, the metal particles M are fluidized under the action of the air blown from the air nozzle 305, and the metal particles M or a part of the oxide MO soars upward than when initially stored. Can happen. In the above chemical loop combustion apparatus A3, the heat resistant wall 322 is formed on the inner wall surface below the oxidation tower 301, so that the heat resistant wall 322 above the horizontal cross sectional area of the region where the heat resistant wall 322 is formed is larger. The horizontal cross-sectional area of the area not 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 325 have a low superficial velocity and are likely to fall downward. Furthermore, since the upper surface of the intermediate header 324 is a conical surface, the metal particles M or their oxides MO dropped on the upper surface of the intermediate header 324 surely fall downward along the surface. Therefore, the oxidation action of the metal particles M can be smoothed and the discharge of the metal particles from the exhaust port 327 at the top of the oxidation tower 301 can be suppressed.

  In the chemical loop combustion apparatus A3, the heat generated by the oxidation of the metal particles M in the oxidation tower 301 is transmitted to the heated fluid flowing in the heat transfer tube 326 via the wall surface of the heat transfer tube 326, and the heated fluid is Heat. That is, in the chemical loop combustion apparatus A3, the heat of the metal particles M generated by the oxidation reaction is transferred to the gas (input air) and at the same time, directly exchanges heat with the heat transfer tube 322 located in the oxidation tower 301. The exhaust gas temperature does not rise greatly. Therefore, NOx generation can be further suppressed. Moreover, since the average temperature of the gas (input air) in the oxidation tower 301 is also lowered, thereby suppressing the superficial velocity, the cross-sectional area of the oxidation tower 301 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 A3, the region below the intermediate header 324 is a region where metal particles are stored, and the heat transfer tube 326 receives a lot of frictional wear due to contact with the metal particles in that region. On the other hand, the region above the intermediate header 324 is a region where gas is mainly present, and the frictional wear of the heat transfer tube 326 is small. Therefore, the material of the heat transfer tube 326 is made of a material having excellent wear resistance in the portion located between the lower header 315 and the intermediate header 324, and compared in the portion located between the intermediate header 324 and the upper header 319. 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 301 circulates from the upper header 319 to the second fluid pipe 321, the heat load unit 300, and the first fluid pipe 318 and returns to the lower header 314. Come. Circulation of the heated fluid to be heated may be reversed.

  In the above example, the first fluid conduit 318 and the second fluid conduit 321 are described as being continuous. However, depending on the type and form of the thermal load unit 300, the first fluid conduit 318 ( And the thermal load 300) and the second fluid line 321 may be discontinuous.

  As described above, in the chemical loop combustion apparatus A3 which is the third form, means necessary for heat exchange of the heated fluid, that is, the lower header 315, the intermediate header 324, the upper header 319, the transmission, are provided in the oxidation tower 301. By arranging the heat pipe 326 and the like, the oxidation reaction heat can actually be used in an on-site industrial boiler or industrial furnace.

<4th form>
FIG. 4 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 chemical loop combustion apparatus A4 according to the fourth embodiment is provided with means necessary for heat exchange of the heated fluid in the oxidation tower 401, that is, a lower header 415, an intermediate header 424, an upper header 419, a heat transfer tube 426, and the like. In the same manner as the chemical loop combustion apparatus A3 of the third embodiment, the oxidation tower 401 and the reduction tower 403 are separated from each other, and both of them are a flow path 450 through which the oxidized metal particles MO move and the reduced metal particles M. Is the same as the chemical loop combustion apparatus A2 of the second embodiment in that it is connected by a flow path 460 that moves. 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 A3, the chemical loop combustion apparatus A4 has a lower header 415, an intermediate header 424, an upper header 419, which are means necessary for heat exchange of the heated fluid in the oxidation tower 401, as described above. Although there are means such as the heat transfer tube 426, there is no means corresponding to the reduction tower. The structure of the oxidation tower 401 is substantially the same as that of the oxidation tower 301 in the chemical loop combustion apparatus A3 except that there is no means corresponding to the reduction tower.

  That is, a required number of air supply pipes 463 extending in the axial direction of the oxidation tower 401 are inserted in the central portion 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. In addition, the metal oxide particles MO are moved to the reduction tower 403 through the metal oxide flow channel 450. For this reason, the metal oxide particles MO are flat in a position slightly above the storage upper end position of the metal particles M stored in the oxidation tower 401. Intermediate header 424, and a first solid-gas separation device 470 is arranged in the 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 of the chemical loop combustion apparatus A3 described with reference to FIG. 3, and the effect obtained by attaching the air supply pipe 463 from above the oxidation tower 401 is also the same as that of FIG. Sometimes it is the same as in the chemical loop combustion apparatus A1, A3 described with reference to FIG. 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. It is almost 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. It is the same as apparatus A2. Also in the chemical loop combustion apparatus A4, the air supply pipe 463 that supplies air into the oxidation tower 401 is provided from the upper part of the oxidation tower 1, and the fuel gas supply pipe 461 that supplies fuel gas into the reduction tower 403 is provided as the reduction tower 403. From the upper part, the chemical loop combustion apparatus A4 can be easily assembled and maintained. In particular, workability can be further improved by using a common mounting substrate 466 as shown in the figure and attaching the plurality of air supply pipes 463 to the same.

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.

Further, 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 range of the ratio, not only the instantaneous value of the fuel and the oxidant but also the accumulated input amount By managing the above, it is possible to determine whether the entire system has approached the oxidation side or the reduction side from the start of operation and to 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 from the reduction tower at a high concentration, the exhaust blower is controlled by an inverter so that the pressure on the reduction tower side is slightly higher than the pressure of 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.

  Next, several modifications of the chemical loop combustion apparatus according to the present invention in which an oxidizing agent and / or a reducing agent are supplied from the top surface side of the reaction tower will be described.

<First Modification of Third Embodiment>
FIG. 5 shows a piping system to which a schematic cross section of a first modification of the chemical loop combustion apparatus A3 of the third embodiment shown in FIG. 3 is attached. In the chemical loop combustion apparatus A3a, the chemical loop combustion apparatus A3 has one reduction tower 303 built in the oxidation tower 301, whereas one oxidation tower 301 is built in the reduction tower 303. The configuration is different from the chemical loop combustion apparatus A3. That is, what was represented as the oxidation tower (outer tower) 301 in FIG. 3 constitutes the reduction tower 303 here. An oxidation tower 301 is attached to the center of the reduction tower 303, and an appropriate number of fuel gas supply pipes 361 are attached so as to drop from the upper part of the reduction tower 303 so as to surround the oxidation tower 301. The fuel gas supply pipe 361 reaches the vicinity of the bottom surface of the reduction tower 303, and the tip part is a fuel nozzle 309. The oxidation tower 301 is composed of an air supply pipe 363 and a required number of separate gas supply pipes 362 arranged along the inner peripheral wall surface of the oxidation tower 301, all reaching the bottom surface of the reduction tower 303. The tip of the air supply pipe 363 is an air nozzle 305, and the tip of the separate gas supply pipe 362 is a separate gas nozzle 313. Further, a solid-gas separation device 325 is attached to the oxidation tower 301 in the same manner as in the reduction tower 303 in the chemical loop combustion apparatus A3 shown in FIG.

  In the reduction tower 303 constituting the outer tower, as in the oxidation tower 301 in the chemical loop combustion apparatus A3 shown in FIG. 3, means necessary for heat exchange of the heated fluid, that is, the lower header 315, the intermediate A header 324, an upper header 319, a heat transfer tube 326, and the like are disposed. Further, a piping system that supplies fuel gas to the fuel gas supply pipe 361, a piping system that sends air (oxidant) to the air supply pipe 363, a piping system that sends inert gas to the separate gas supply pipe 362, and a reduction tower 303 The piping system for treating the exhaust gas and the exhaust gas from the oxidation tower 301 is the same as that in the chemical loop combustion apparatus A3 shown in FIG. These are denoted by the same reference numerals in FIG.

<Second Modification of Third Embodiment>
FIG. 6 shows a piping system to which a schematic cross section of a second modification of the chemical loop combustion apparatus A3 of the third embodiment shown in FIG. 3 is attached. This chemical loop combustion apparatus A3b is attached such that one oxidation tower 301 is incorporated in the reduction tower 303, and the oxidation tower 301 and the fuel gas supply pipe 361 are dropped from the upper part of the reduction tower 303. This is the same as the chemical loop combustion apparatus A3a described with reference to FIG. 5 except that the air nozzle 305 and the separate gas nozzle 313 are attached to the bottom side of the reduction tower 303.

  That is, an air header 304 is attached to the bottom of the reduction tower 303, and the tip thereof is an air nozzle 305. The outer periphery of the air header 304 is a separate gas supply pipe 362, and the tip of the air header 304 is a separate gas nozzle 313. The air header 304 is supplied with regulated air from the blower 306, and the separate gas supply pipe 362 is supplied with an inert gas. Therefore, in the chemical loop combustion apparatus A3b, the oxidation tower 303 is a simple tower body.

  A piping system for supplying fuel gas to the fuel gas supply pipe 361, a piping system for sending inert gas to the separate gas supply pipe 362, and a piping system for processing exhaust gas from the reduction tower 303 and exhaust gas from the oxidation tower 301 are shown in FIG. Are substantially the same as those in the chemical loop combustion apparatus A3a shown in FIG. 6, and the same reference numerals are given in FIG.

  In this chemical loop combustion apparatus A3b, the air (oxidant) ejected from the air nozzle 305 flows into the oxidation tower 303 to advance the oxidation reaction of the metal particles moving in the oxidation tower. Further, mixing of the oxidizing agent and the reducing agent can be prevented by the inert gas ejected from the separate gas nozzle 313 provided around the air nozzle 305. Furthermore, also in this aspect, the oxidation tower 301 and the fuel gas supply pipe 361 are detachable from the top surface side of the reduction tower 303, and the ease of assembly and maintenance of the apparatus can be ensured.

<Third Modification of Third Embodiment>
FIG. 7 shows a piping system to which a schematic cross section of a third modification of the chemical loop combustion apparatus A3 of the third embodiment shown in FIG. 3 is attached. In this chemical loop combustion apparatus A3c, one oxidation tower 301 is incorporated in the reduction tower 303, and the oxidation tower 301 is disposed along the inner peripheral wall surface of the air supply pipe 363 and the oxidation tower 301. The required number of separate gas supply pipes 362 are installed so as to drop from the upper part of the reduction tower 303, and the oxidizing agent is supplied from the air nozzle 305 at the lower end of the air supply pipe 363 to the oxidation tower 301. However, the fuel gas supply pipe 361 and the fuel nozzle 309 are attached to the bottom of the reduction tower 303 for the purpose of reduction. The tower 303 is different from the chemical loop combustion apparatus A3a in that the fuel gas supply pipe 361 is not provided in the tower 303.

  The piping system for supplying the fuel gas to the fuel gas supply pipe 361 and the piping system for processing the exhaust gas from the reduction tower 303 and the exhaust gas from the oxidation tower 301 are substantially the same as those in the chemical loop combustion apparatus A3a shown in FIG. These are denoted by the same reference numerals in FIG. 6 and description thereof is omitted.

  In this chemical loop combustion apparatus A3c, the fuel gas ejected from the fuel nozzle 309 at the bottom of the reduction tower 303 advances the reduction reaction of the metal oxide particles in the reduction tower 303. Moreover, mixing of the oxidizing agent and the reducing agent can be prevented by the inert gas ejected from the separate gas nozzle 313 provided at the lower end of the oxidation tower 301. Furthermore, also in this aspect, the oxidation tower 301 is detachable from the top surface side of the reduction tower 303, and the ease of assembly and maintenance of the apparatus can be ensured.

<Fourth Modification of Third Embodiment>
FIG. 8 shows a piping system to which a schematic cross section of a fourth modification of the chemical loop combustion apparatus A3 of the third embodiment shown in FIG. 3 is attached. This chemical loop combustion apparatus A3d is different from the chemical loop combustion apparatus A3a shown in FIG. 5 only in that a plurality of (two in the illustrated example) oxidation towers 301, 301 are provided inside the reduction tower 303. The configuration is different. Other configurations are basically the same as those in the case of the chemical loop combustion apparatus A3a.

  In the chemical loop combustion apparatus A3d, the two oxidation towers 301 and 301 are disposed in the reduction tower 303 in a posture parallel to the axial center line of the reduction tower 303. The conditioned air is supplied, and an inert gas is supplied to the separate gas nozzles 313 and 313 through the pipe 314.

  Although not shown and described, in the chemical loop combustion apparatus in which a plurality of oxidation towers are provided inside the reduction tower as shown in FIG. It is possible to adopt a configuration in which the separate gas nozzle 313 is disposed at the bottom of the reduction tower 303, or a configuration in which the fuel nozzle 309 is disposed at the bottom of the reduction tower 303 as shown in FIG.

<Fifth Modification of Third Embodiment>
FIG. 9 shows a piping system to which a schematic cross section of a fifth modification of the chemical loop combustion apparatus A3 of the third embodiment shown in FIG. 3 is attached. This chemical loop combustion apparatus A3e is provided with a plurality of (two in the illustrated example) reduction towers 303, 303 in the oxidation tower 301 instead of one, and a change necessary for the piping system accordingly. The configuration is different from the chemical loop combustion apparatus A3 shown in FIG. The other configuration is basically the same as that of the chemical loop combustion apparatus A3 shown in FIG. 3, and the description of the configuration and operation is omitted by giving the same reference numerals.

<Sixth Modification of Third Embodiment>
FIG. 10 shows a piping system to which a schematic cross section of a sixth modification of the chemical loop combustion apparatus A3 of the third embodiment shown in FIG. 3 is attached. This chemical loop combustion apparatus A3f includes two reduction towers 303 incorporated in the oxidation tower 301, and a fuel gas supply pipe 361 and a separate gas supply pipe 362 constituting the reduction tower 303 are provided above the oxidation tower 301. 9 is the same as the chemical loop combustion apparatus A3e described with reference to FIG. 9 except that an appropriate number of air nozzles 305 are attached to the bottom of the oxidation tower 301. 9 is different from the chemical loop combustion apparatus A3e shown in FIG. 9 in that the air supply pipe 363 is not provided in the oxidation tower 301.

  That is, an air header 304 is attached to the bottom of the oxidation tower 301, and the tip thereof is an air nozzle 305. The other configurations are basically the same as those in the case of the chemical loop combustion apparatus A3e shown in FIG. In this chemical loop combustion apparatus A3f, the air (oxidant) ejected from the air nozzle 305 flows into the oxidation tower 303 to advance the oxidation reaction of the metal particles moving in the oxidation tower. It flows into the reduction tower 303. Further, mixing of the oxidizing agent and the reducing agent can be prevented by the inert gas ejected from the separate gas nozzle 313 provided around each reducing tower 303. Also in this aspect, the reduction tower 303, the fuel gas supply pipe 361, and the separate gas supply pipe 362 are detachable from the top surface side of the oxidation tower 301, and the ease of assembly and maintenance of the apparatus can be ensured.

<Seventh Modification of Third Embodiment>
FIG. 11 shows a piping system to which a schematic cross section of a seventh modification of the chemical loop combustion apparatus A3 of the third embodiment shown in FIG. 3 is attached. This chemical loop combustion apparatus A3g has a point in which two reduction towers 303 are incorporated in the oxidation tower 301, and an air supply pipe 363 and a reduction tower 303 are attached so as to drop from the upper part of the oxidation tower 301. 9 is the same as the chemical loop combustion apparatus A3e described with reference to FIG. 9 except that a fuel gas supply pipe 361 and a separate gas nozzle 313 are attached to a position facing the reduction tower 303 at the bottom of the oxidation tower 301. The leading ends thereof are a fuel nozzle 309 and a separate gas nozzle 313, and therefore, the two reduction towers 303 are merely cavities, and are different from the chemical loop combustion apparatus A3e described with reference to FIG. ing.

  The piping system for supplying the fuel gas to the fuel gas supply pipe 361 and the piping system for processing the exhaust gas from the reduction tower 303 and the exhaust gas from the oxidation tower 301 are substantially the same as those in the chemical loop combustion apparatus A3 shown in FIG. These are denoted by the same reference numerals in FIG. 11 and description thereof is omitted.

  In the chemical loop combustion apparatus A3g, the reduction reaction of the metal oxide particles in the two reduction towers 303 proceeds by the fuel gas ejected from the fuel nozzle 309 at the bottom of the oxidation tower 301. Further, mixing of the oxidant and the reducing agent can be prevented by the inert gas ejected from the separate gas nozzle 313 provided around the fuel nozzle 309. Furthermore, also in this aspect, the air supply pipe 363 and the reduction tower 303 are detachable from the top surface side of the oxidation tower 301, and the ease of assembly and maintenance of the apparatus can be ensured.

  In the first to seventh modifications of the chemical loop combustion apparatus A3 of the third embodiment described above, it is necessary for heat exchange of the heated fluid provided in the chemical loop combustion apparatus A3 of the third embodiment shown in FIG. In other words, the configuration of the lower header 315, the intermediate header 324, the upper header 319, the heat transfer tube 326, etc. is commonly applied to each modification, and does not directly affect the configuration of each modification. Absent. This also applies to the chemical loop combustion apparatus that does not include means necessary for heat exchange of the heated fluid, that is, the internal circulation type chemical loop combustion apparatus A1 shown in FIG. This means that all of them can be applied, and a detailed description thereof is omitted. Although not shown in the drawings, all of the modifications based on the internal circulation type chemical loop combustion apparatus A1 shown in FIG. 1 are also within the scope of the present invention. Is.

<First Modification of Fourth Embodiment>
FIG. 12 shows a piping system to which a first modification of the external circulation type chemical loop combustion apparatus having means necessary for heat exchange of the heated fluid according to the fourth embodiment shown in FIG. 4 is provided. . This external circulation type chemical loop combustion apparatus A4a is different from the chemical loop combustion apparatus A4 shown in FIG. 4 in that fuel gas is supplied from the bottom surface side of the reduction tower 403. Other configurations are the same, and the description is omitted by giving the same reference numerals.

  That is, in the external circulation type chemical loop combustion apparatus A4a, the fuel gas supply pipe 461 is attached to the bottom of the reduction tower 403, and the tip thereof is opened as a fuel nozzle 409 in the reduction tower 403. The piping system for supplying fuel to the fuel gas supply pipe 461 is the same as that of the chemical loop combustion apparatus A4, and the description thereof is omitted. Also in the chemical loop combustion apparatus A4a of this aspect, the air supply pipe 463 is detachable from the top surface side of the oxidation tower 401, and the ease of assembly and maintenance of the apparatus can be ensured.

<Second Modification of Fourth Embodiment>
FIG. 13 shows a piping system to which a second modification of the external circulation type chemical loop combustion apparatus of the fourth embodiment shown in FIG. 4 is attached. This external circulation type chemical loop combustion apparatus A4b is different from the chemical loop combustion apparatus A4 shown in FIG. 4 in that air (oxidant) is supplied from the bottom side of the oxidation tower 401. Other configurations are the same, and the description is omitted by giving the same reference numerals.

  That is, in the external circulation type chemical loop combustion apparatus A4b, the air header 404 is attached to the bottom of the oxidation tower 401, and the tip of the air header 404 opens into the oxidation tower 401 as an air squeal 405. There is no air supply pipe 463 in the oxidation tower 401. The air header 404 is supplied with pressure-regulated air through a blower 406, a flow meter 407, and a pressure regulating valve 408, and is ejected from the air nozzle 5 into the oxidation tower 1.

  Also in the chemical loop combustion apparatus A4b of this aspect, the fuel gas supply pipe 461 is detachable from the top surface side of the reduction tower 403, and the ease of assembly and maintenance of the apparatus can be ensured.

  In the first and second modified examples of the chemical loop combustion apparatus A4 of the fourth embodiment described above, the heat exchange of the heated fluid provided in the chemical loop combustion apparatus A4 of the fourth embodiment shown in FIG. Necessary means, that is, the configuration of the lower header 415, the intermediate header 424, the upper header 419, the heat transfer tube 426, etc. is commonly applied to each modification, and directly affects the configuration of each modification. is not. This also applies to the chemical loop combustion apparatus that does not include means necessary for heat exchange of the heated fluid, that is, the external circulation type chemical loop combustion apparatus A2 shown in FIG. This means that the present invention can be applied, and a detailed description thereof is omitted. Although not shown in the drawings, all of the modifications based on the external circulation type chemical loop combustion apparatus A2 shown in FIG. 2 are also within the scope of the present invention. It is.

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,
2 ... The top plate (top) of the oxidation tower,
3 ... reduction tower,
5 ... Air nozzle,
9 ... Fuel nozzle,
13 ... Separate gas nozzle,
16 ... the upper surface of the heat-resistant bottom of the oxidation tower,
22a: Thickness region on the inner peripheral surface of the oxidation tower,
22b ... Conical wall at the upper end surface of the thick region,
25. Solid-gas separation device,
27 ... The exhaust port at the top of the oxidation tower,
28 ... Solid-gas separation device,
29 ... heat exchanger,
29a ... heat exchanger,
33. Steam-water separator,
61 ... Fuel gas supply pipe,
62 ... Separate gas supply pipe,
63 ... Air supply pipe,
63a ... an air supply pipe that also functions as a temperature raising burner,
66 ... Common mounting board,
M ... metal particles,
MO: Metal oxide particles.

Claims (8)

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 And 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,
Either or both of the oxidizing agent supply pipe for supplying the oxidizing agent into the oxidizing tower and the reducing agent supply pipe for supplying the reducing agent into the reducing tower are directed from the top side to the bottom side of the respective reaction towers. A chemical loop combustion apparatus, wherein the chemical loop combustion apparatus is inserted.   2. The chemical loop combustion apparatus according to claim 1, wherein one or more of the reduction towers are incorporated in the oxidation tower. 3.   3. The chemical loop combustion apparatus according to claim 2, wherein a bottom surface of the oxidation tower has a mortar-like surface curved downward. 4.   2. The chemical loop combustion apparatus according to claim 1, wherein one or more of the oxidation towers are incorporated in the reduction tower.   4. The chemical loop combustion apparatus according to claim 3, wherein a bottom surface of the reduction tower has a mortar-like surface curved downward. 5.   6. The chemical loop combustion apparatus according to claim 1, wherein the oxidation tower includes a plurality of oxidant supply pipes, and some of the oxidant supply pipes include an oxidant and a reducing agent. And a chemical loop combustion apparatus characterized by being capable of being selectively supplied.   2. The chemical loop combustion apparatus according to claim 1, wherein the oxidation tower and the reduction tower are separated, and both are connected by a flow path of oxidized metal particles and a flow path of reduced metal particles. A chemical loop combustion apparatus characterized by comprising:   8. The chemical loop combustion apparatus according to claim 1, wherein reaction heat is transferred to a fluid to be heated in contact with the metal particles or oxide thereof in the oxidation tower or reduction tower. A chemical loop combustion apparatus in which a heat transfer tube is disposed.

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