JP7194494B2 - Chemical looping combustion system - Google Patents

Description

The present invention relates to chemical looping combustion systems.

Examples of types of chemical looping combustion (CLC) systems (hereinafter also referred to as CLC systems) include a circulation type and a switching type. A circulating CLC system has a reduction reaction chamber in which the fuel is oxidized with oxygen carrier particles and the oxygen carrier particles are reduced, and an oxidation reaction chamber in which the reduced oxygen carrier particles are oxidized with an oxidizing gas. During operation of the circulating CLC system, oxygen carrier particles are circulated between the reaction chambers by piping.

A switched CLC system has a reaction chamber alternately supplied with an oxidizing gas and a fuel, as disclosed in US Pat. During operation of the switching type CLC system, an oxidation reaction in which the fuel is oxidized and reduced oxygen carrier particles are oxidized with an oxidizing gas, and a reduction reaction in which the fuel is oxidized by the oxygen carrier particles and the oxygen carrier particles are reduced. It is repeated alternately while being switched within the same reaction chamber.

Gas exhausted from the reaction chamber of the CLC system is heat-recovered by a given heat-recovery device. In the CLC system, the fuel is oxidized without direct contact with air, so the components of the exhaust gas from each reaction chamber are almost exclusively carbon dioxide (CO ₂ ) and water vapor (H ₂ O). Therefore, the CLC system can prevent the generation of nitrogen oxides (NO _x ) accompanying fuel oxidation, and can easily separate and recover carbon dioxide from the exhaust gas at low cost. The CLC system is regarded as a strong candidate for CCS technology for separating and recovering carbon dioxide from the exhaust gas of facilities such as thermal power plants.

Japanese Patent No. 5820669

Since different reactions are alternately repeated in the reaction chamber of the switching CLC system during operation, the exhaust heat of the exhaust gas discharged from the reaction chamber is, for example, the amount of heat exhausted from the reaction chamber during operation of the circulating CLC system. It fluctuates greatly compared to the exhaust heat amount of the exhaust gas. Therefore, in the switching type CLC system, the amount of heat recovered from the exhaust gas by the heat recovery device also fluctuates greatly.

In addition, in general, the switching type CLC system supplies the oxidizing gas or fuel into the reaction chamber at predetermined timings. The supply volume per unit time is large. As a result, in the switching type CLC system, there is a risk that the incidental equipment for supplying the oxidizing gas and the fuel to the reaction chamber will become large.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to suppress variation in the amount of heat recovered in a heat recovery device while preventing ancillary equipment from becoming large in a switchable CLC system.

In order to solve the above problems, a chemical looping combustion system according to one aspect of the present invention includes a plurality of reaction chambers in which a fluidized bed containing oxygen carrier particles is arranged, and the plurality of reaction chambers are individually connected to each other, a fuel supply passage through which fuel flows and provided with a plurality of first supply devices capable of individually adjusting a fuel flow rate to each reaction chamber of the plurality of reaction chambers; an oxidizing gas supply path through which the oxidizing gas flows and which is provided with a plurality of second supply devices capable of individually adjusting the flow rate of the oxidizing gas to each of the reaction chambers; and the plurality of first and second supply devices. and a heat recovery device for recovering heat from the exhaust gases of the plurality of reaction chambers, wherein the control device individually controls the plurality of first and second supply devices to control the first At the timing, a specific number of reaction chambers among the plurality of reaction chambers are set as reduction chambers in which the fuel is oxidized and the oxygen carrier particles are reduced by the oxidized and fluidized oxygen carrier particles, and the remaining reaction chambers are is set as an oxidation chamber for oxidizing the oxygen carrier particles reduced with the oxidation of the fuel with an oxidizing gas, and at a second timing after the first timing, the reduction is performed at the first timing The plurality of switching control for switching the reaction chambers is repeatedly executed.

According to the above configuration, the switching control by the control device is repeatedly executed while the oxidation chamber and the reduction chamber exist at a constant ratio. As a result, the oxidation reaction and the reduction reaction of the oxygen carrier particles can be performed at a constant rate in the reaction chambers as a whole, so that the heat recovery amount of the heat recovery device that recovers heat from the exhaust gas of each reaction chamber can be made constant. Therefore, it is possible to prevent the heat recovery amount from greatly fluctuating during system operation. In addition, fluctuations in the amount of fuel and oxidizing gas supplied to multiple reaction chambers as a whole can be suppressed. can be suppressed.

The plurality of reaction chambers includes at least three or more reaction chambers, and the control device sets one reaction chamber among the plurality of reaction chambers as the reduction chamber and sets reaction chambers other than the reduction chamber as the reduction chamber. The switching control may be repeatedly performed so that the oxidation chamber is set and each of the reaction chambers is sequentially set as the reduction chamber.

According to the above configuration, the switching control is executed so that each of the reaction chambers among the plurality of reaction chambers is sequentially set to the reduction chamber, whereby the oxidation reaction of the oxygen carrier particles and the fuel and the oxidation reaction can be performed evenly, and it is possible to further prevent the amount of heat recovery from fluctuating greatly during system operation.

A fuel gasifying agent supply provided with a plurality of third supply devices individually connected to the plurality of reaction chambers, through which the fuel gasifying agent flows, and capable of individually adjusting the flow rate of the fuel gasifying agent to each of the reaction chambers. wherein the fuel is a solid fuel, and the controller individually controls the plurality of first, second, and third feeders to cause, at the first timing, in the reduction chamber fluidizing the oxidized oxygen carrier particles and the solid fuel with a fuel gasifying agent, oxidizing the solid fuel gasified with the fuel gasifying agent by the oxidized oxygen carrier particles, and The particles may be reduced.

According to the above configuration, by using the fuel gasifying agent, the oxidized oxygen carrier particles efficiently fluidize the oxidized oxygen carrier particles and the solid fuel in the reduction chamber, and the oxidized oxygen carrier particles are used to gas the fuel gasifying agent. oxidized solid fuel.

A gas-permeable support member may be provided inside each of the plurality of reaction chambers to support the oxygen carrier particles above the fluidized bed. As a result, even if unreacted gas is generated in the fluidized bed when oxidizing the solid fuel, the oxygen carrier particles supported by the gas-permeable support member efficiently oxidize the unreacted gas that has passed through the support member. be able to. Therefore, the carbon dioxide conversion rate of the fuel can be improved, and the unreacted gas can be prevented from being discharged outside the reaction chamber, thereby reducing the environmental load.

In addition, since the fluidized bed composed of the support member and the oxygen carrier particles supported by the support member is provided above the fluidized bed, it is possible to prevent an increase in the installation area of the plurality of reaction chambers, and the cost is relatively low. Can configure the system.

The fuel is gas fuel, and the control device fluidizes the oxidized oxygen carrier particles with the gas fuel in the reduction chamber at the first timing to cause the oxidized oxygen carrier particles to The gaseous fuel may be oxidized and the oxygen carrier particles may be reduced.

Thus, when gas fuel is used as the fuel, the fuel gasifying agent and the fuel gasifying agent supply path can be omitted, and when the reduction chamber is set by the control device, the oxygen carrier particles are is fluidized, a reduction reaction of the oxygen carrier particles can be obtained.

A single furnace body may be provided in which the plurality of reaction chambers and partition walls for individually partitioning the plurality of reaction chambers are formed. As a result, the furnace can be configured compactly, the installation area of multiple reaction chambers can be reduced, and the size of the system can be suppressed well. can be done easily.

The control device makes the amount of oxygen carrier particles oxidized by the oxidizing gas in the oxidation chamber greater than the amount of oxygen carrier particles reduced by oxidation of the fuel in the reduction chamber by performing the switching control once. , the switching control may be executed.

As a result, even when a gas with a relatively low oxygen concentration, such as air, is used as the oxidizing gas, the oxygen carrier particles, which have been reduced as the fuel is oxidized in the reducing chamber, are appropriately oxidized by the oxidizing gas in the oxidation chamber. can be made easier.

According to each aspect of the present invention, in a switchable CLC system, fluctuations in the amount of heat recovered in the heat recovery device can be suppressed while preventing ancillary equipment from increasing in size.

1 is a schematic diagram of a CLC system according to a first embodiment; FIG. It is a figure which shows the time chart in switching control of 1st Embodiment. FIG. 4 is a schematic diagram of a CLC system according to a second embodiment; FIG. 11 is a schematic diagram of a CLC system according to a third embodiment;

Hereinafter, each embodiment will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic diagram of a CLC system 1 according to the first embodiment. The CLC system 1 is a switching type, and as shown in FIG. machine 8, a plurality of first (fuel) supply devices 9, a plurality of fuel supply paths R1, oxidizing gas supply paths R2, fuel gasification agent supply paths R3, first exhaust gas discharge paths R4, and second exhaust gas discharge A path R5 is provided.

The CLC furnace 2 has a plurality of reaction chambers 2a and partition walls 2b partitioning the plurality of reaction chambers 2a. The plurality of reaction chambers 2a in this embodiment includes at least three or more (four as an example) reaction chambers 2a. The shape of the reaction chamber 2a can be set appropriately. In this embodiment, the plurality of reaction chambers 2a have the same shape and extend vertically.

A fluidized bed (fluidized bed) 2c containing oxygen carrier particles is arranged inside the reaction chamber 2a. The fluidized bed 2c is fluidized inside the reaction chamber 2a by gas supplied from the outside from the lower side of the reaction chamber 2a. That is, the fluidized bed 2c is enclosed within the reaction chamber 2a and does not flow between the plurality of reaction chambers 2a.

The oxygen carrier particles of this embodiment contain iron. The main component of the oxygen carrier particles is, for example, Fe ₂ O ₃ (ferric oxide (III)) in the oxidized state and Fe ₃ O ₄ (triiron tetraoxide (II, III) in the reduced state). )). The material of the oxygen carrier particles is not limited. Oxygen carrier particles may include metals such as titanium, nickel, copper, manganese, or aluminum.

During operation of the CLC system 1, each reaction chamber 2a is alternately and repeatedly switched between the reduction chamber and the oxidation chamber at predetermined timings by switching control executed by the controller 3, which will be described later. The reaction chamber 2a set as a reduction chamber fluidizes the oxidized oxygen carrier particles and the fuel with the fuel gasifying agent, and the oxidized oxygen carrier particles oxidize the gasified fuel with the fuel gasifying agent. and reduce the oxygen carrier particles.

The reaction chamber 2a, which is set as an oxidation chamber, oxidizes the oxygen carrier particles, which have been reduced as the fuel is oxidized, with an oxidizing gas. The oxidation chamber of the present embodiment is an air reaction chamber for oxidizing the oxygen carrier particles that have been reduced as the fuel is oxidized with air, which is an oxidizing gas.

The partition wall 2b separates the plurality of reaction chambers 2a individually. By providing the partition wall 2b, the upper space (free board) located above the fluidized bed 2c of each reaction chamber 2a is isolated for each reaction chamber 2a. As a result, in the CLC furnace 2, the gases in the upper space of each reaction chamber 2a are not mixed.

As described above, the CLC system 1 includes the CLC furnace 2 as a single furnace body in which a plurality of reaction chambers 2a and partition walls 2b for individually partitioning the plurality of reaction chambers 2a are formed. In this embodiment, all the reaction chambers 2a have the same volume and the same amount of oxygen carrier particles are placed in all the reaction chambers 2a.

The plurality of fuel supply paths R1 are individually connected to the respective reaction chambers 2a, and the plurality of first supply devices 9 through which the fuel flows and can individually adjust the fuel flow rate to each reaction chamber 2a among the plurality of reaction chambers 2a. is provided. The fuel in this embodiment is a solid fuel, such as coal. The upstream end of the fuel supply path R1 is connected to each first supply device 9, and the downstream end of the fuel supply path R1 is connected to each reaction chamber 2a.

In the configuration shown in FIG. 1, the fuel is supplied from the side of the reaction chamber 2a to the fluidized bed 2c, but the method and position of supplying the fuel to the reaction chamber 2a are not limited to this. Moreover, the solid fuel may be a solid containing a carbon component, such as biomass.

The oxidizing gas supply path R2 is individually connected to the plurality of reaction chambers 2a, and provided with a plurality of second supply devices 13 through which the oxidizing gas flows and which can individually adjust the flow rate of the oxidizing gas to each of the reaction chambers 2a. It is The oxidizing gas is, by way of example, air or oxygen-enriched air.

An upstream end of the oxidizing gas supply path R2 is connected to a pump (not shown) for taking in outside air. The downstream end of the oxidizing gas supply path R2 is branched, and each branched path is connected to the lower side of each reaction chamber 2a via the second supply device 13. As shown in FIG.

The fuel gasifying agent supply paths R3 are individually connected to the plurality of reaction chambers 2a, through which the fuel gasifying agent flows, and a plurality of third supply devices capable of individually adjusting the flow rate of the fuel gasifying agent to each reaction chamber 2a. 14 are provided. The fuel gasification agent is, for example, water vapor, carbon dioxide gas, or a mixture of water vapor and carbon dioxide gas.

The upstream end of the fuel gasifying agent supply path R3 is connected to a pump (not shown) for taking in the fuel gasifying agent from the fuel gasifying agent supply source. The downstream end of the fuel gasifying agent supply path R3 is branched, and each branched path is connected to the lower side of each reaction chamber 2a via the third supply device 14. As shown in FIG.

The ends of the branched channels of the oxidizing gas supply channel R2 and the fuel gasifying agent supply channel R3 are further branched into a plurality of branches and connected to the lower sides of the respective reaction chambers 2a. As a result, the oxidizing gas and the fuel gasifying agent can be supplied to the reaction chamber 2a at predetermined timings from a plurality of positions below the reaction chamber 2a.

A plurality of supply paths R2 and R3 may be provided individually for each reaction chamber 2a. In this case, each second supply device 13 may be provided individually for each oxidizing gas supply path R2, and each third supply device 14 may be provided individually for each fuel gasification agent supply path R3. may be provided in

The first exhaust gas discharged from the reaction chamber 2a set as the oxidation chamber flows through the first exhaust gas discharge passage R4. A main component of the first exhaust gas is, for example, nitrogen. The upstream end of the first exhaust gas discharge path R4 is branched, and the branched path is connected to the upper side of each reaction chamber 2a via a flow path controller 15. As shown in FIG. The downstream end of the first exhaust gas discharge path R4 is open to the outside after passing through the first heat exchanger 4 and the first dust collector 6 in order from the upstream side to the downstream side.

The second exhaust gas discharged from the reaction chamber 2a set as the reduction chamber flows through the second exhaust gas discharge path R5. The main components of the second exhaust gas are, for example, carbon dioxide and water. The upstream end of the second exhaust gas discharge channel R5 is connected to the upper side of each reaction chamber 2a via a channel regulator 15 and a branch channel of the first exhaust gas discharge channel R4. The downstream end of the second exhaust gas discharge path R5 passes through the second heat exchanger 5, the second dust collector 7, and the dehydrator 8 in order from the upstream side to the downstream side, and is open to the outside. .

The first heat exchanger 4 and the second heat exchanger 5 are heat recovery devices that recover heat from the exhaust gas (first exhaust gas and second exhaust gas) of each reaction chamber 2a. The first heat exchanger 4 recovers heat from the first exhaust gas and the second heat exchanger 5 recovers heat from the second exhaust gas. The dehydrator 8 dehydrates the second exhaust gas. By being dehydrated by the dehydrator 8, the component of the second exhaust gas is almost exclusively carbon dioxide.

The control device 3 controls the plurality of supply devices 9, 13, 14 individually. The control device 3 is connected to the plurality of supply devices 9, 13, 14, and controls the plurality of supply devices 9, 13, 14 so as to adjust the flow rate of the liquid flowing through the flow path provided with the plurality of supply devices 9, 13, 14. 9, 13, 14 are controlled.

The control device 3 also individually controls the plurality of flow path regulators 15 . The control device 3 is connected to the plurality of flow path regulators 15 and controls the plurality of flow path regulators 15 so as to circulate the distribution material through either of the flow paths R4 and R5.

The control device 3 is, for example, a computer having a CPU, ROM, and RAM. A predetermined control program is stored in the ROM. The control device 3 controls each element 9, 13, 14, 15 based on this control program.

Here, the control device 3 individually controls the supply devices 9, 13, and 14 at predetermined timings to set a specific number of the reaction chambers 2a among the plurality of reaction chambers 2a as reduction chambers at a first timing. At the same time, the remaining reaction chamber 2a is set as the oxidation chamber, and at the second timing after the first timing, the reaction chamber 2a set as the reduction chamber at the first timing is set as the oxidation chamber, and at the first timing, the reaction chamber 2a is set as the oxidation chamber. Switching control for switching a plurality of reaction chambers 2a is repeatedly executed so that the same number of reaction chambers 2a as the specific number among the reaction chambers 2a set to 2 are set as reduction chambers.

As the switching control, the control device 3 of the present embodiment sets three of the four reaction chambers 2a (A to D) of the CLC furnace 2 as oxidation chambers at each of the first and second timings. , is set as the reduction chamber (that is, the specific number is set to 1), the switching control is repeatedly executed. As a result, the control device 3 repeatedly executes the switching control while allowing the oxidation chamber and the reduction chamber to exist at a constant ratio.

In the example shown in FIG. 1, the control device 3 opens the supply by the supply devices 9 and 14 and stops the supply by the supply device 13 to one reaction chamber 2a (A), and the flow path regulator 15 is adjusted so that the gas flows toward the second exhaust gas discharge passage R5. The control device 3 also stops the supply from the supply devices 9 and 14 and opens the supply from the supply device 13 to the remaining reaction chambers 2a (B to D) other than the one reaction chamber 2a (A). , the flow path adjuster 15 is adjusted so that the gas flows to the first exhaust gas discharge path R4 side. As a result, FIG. 1 shows a state in which the control device 3 performs switching control so that the one reaction chamber 2a (A) is used as a reduction chamber and the remaining reaction chambers 2a (B to D) are used as oxidation chambers. ing.

Hereinafter, a method for operating the CLC system 1 according to this embodiment will be specifically described. During operation of the CLC system 1, the control device 3 supplies fuel and fuel gasifying agent to a specific number of reaction chambers 2a and supplies oxidizing gas to the remaining reaction chambers 2a. It controls the devices 9,13,14. Further, the control device 3 distributes the second exhaust gas discharged from the specific number of reaction chambers 2a to the second exhaust gas discharge path R5, and distributes the first exhaust gas discharged from the remaining reaction chambers 2a to the second discharge gas discharge path R5. 1 exhaust gas discharge path R4, the flow path adjuster 15 is controlled. As a result, the controller 3 sets the specific number of reaction chambers 2a as reduction chambers and sets the remaining reaction chambers 2a as oxidation chambers.

In the oxidation chamber, the oxidizing gas that has passed through the oxidizing gas supply path R2 is jetted into the oxidation chamber from a plurality of positions below the oxidation chamber. The oxidizing gas is mixed as air bubbles in the fluidized bed 2c in the oxidation chamber. Oxygen carrier particles in the oxidation chamber are oxidized by the oxidizing gas jetted into the oxidation chamber and generate heat due to reaction heat. The amount of heat generated at this time is accumulated in the fluidized bed 2c of the oxidation chamber. The first exhaust gas is generated by the oxidation of the oxygen carrier particles. The first exhaust gas passes through the upper space of the oxidation chamber, is discharged to the branched passage of the first exhaust gas discharge passage R4, and flows through the first exhaust gas discharge passage R4 toward the downstream side via the passage regulator 15. do.

When air is used as the oxidizing gas, the components of the first exhaust gas are almost exclusively nitrogen (N ₂ ) and oxygen (O ₂ ). Since the oxidation temperature of the oxygen carrier particles is not so high, even if an oxidizing gas containing a nitrogen component is used, the oxygen carrier particles are less likely to be oxidized to produce nitrogen oxides.

In the reduction chamber, the fuel that has passed through the fuel supply path R1 is supplied into the reduction chamber, and the fuel gasification agent that has passed through the fuel gasification agent supply path R3 enters the reduction chamber from a plurality of positions below the reduction chamber. erupt. The fuel gasification agent mixes in the fluidized bed 2c in the reduction chamber as air bubbles.

Oxygen carrier particles in the reduction chamber mix with the fuel and flow due to the fuel gasifying agent ejected into the reduction chamber. The fuel is gasified by the fuel gasifying agent, oxidized by the oxygen in the oxygen carrier particles, and the oxygen carrier particles are reduced.

A second exhaust gas is generated by the oxidation of the fuel, the reduction of the oxygen carrier particles, and the fuel gasifying agent that has passed through the fluidized bed 2c. The second exhaust gas passes through the upper space of the reduction chamber, is discharged to the branched passage of the first exhaust gas discharge passage R4, and flows downstream through the second exhaust gas discharge passage R5 via the passage adjuster 15. do. When water vapor is used as the fuel gasification agent, the second exhaust gas component is almost exclusively carbon dioxide and water vapor.

Here, since the oxidation chamber and the reduction chamber are separated by the partition wall 2b, unreacted carbon components in the reduction chamber are prevented from entering the oxidation chamber. Therefore, in the CLC furnace 2, the carbon component is oxidized in the oxidation chamber, the carbon component is mixed in the composition of the first exhaust gas, and the carbon conversion rate of the solid fuel in the reduction chamber is reduced. prevented. Thus, the CLC furnace 2 has a separator structure (carbon separator) for preventing unreacted carbon components in the reduction chamber from entering the oxidation chamber.

When the control device 3 determines that the oxidation of the fuel in the reduction chamber has completed up to a predetermined standard, the control device 3 oxidizes a specific number (one in this embodiment) of the reaction chambers 2a set as reduction chambers. Among the remaining (three in this embodiment) reaction chambers 2a set as oxidation chambers, the same number of reaction chambers 2a as the reaction chambers 2a set as reduction chambers immediately before the determination is set in the reduction chamber. The control device 3 repeatedly executes this switching control at a predetermined timing each time the determination is made.

FIG. 2 is a diagram showing a time chart in switching control of the first embodiment. In FIG. 2, "AR" indicates that the reaction chamber 2a is set as an oxidation chamber in which the reaction between the reduced oxygen carrier particles and the oxidizing gas (air) takes place, and "FR" indicates that the reaction Chamber 2a is shown set as a reduction chamber in which the reaction between the oxidized oxygen carrier particles and the fuel takes place.

The control device 3 of the present embodiment sets one of the plurality of reaction chambers 2a as a reduction chamber and sets the other reaction chambers 2a as oxidation chambers at first and second timings, which will be described later. At the same time, switching control is repeatedly executed so that each reaction chamber 2a among the plurality of reaction chambers 2a is sequentially set as the reduction chamber.

Specifically, in the example shown in FIG. 2, the control device 3 executes the switching control each time the times t1 to t8 have passed. As an example, in the switching control at time t1 (first timing), the reaction chamber A is set as the reduction chamber, and the reaction chambers BD are set as the oxidation chambers.

In the switching control at time t2 (second timing), the reaction chamber B is set as the reduction chamber, and the reaction chambers A, C, and D are set as the oxidation chambers. In the switching control at time t3 (first timing), the reaction chamber C is set as the reduction chamber, and the reaction chambers A, B, and D are set as the oxidation chambers.

In the switching control at time t4 (second timing), the reaction chamber D is set as the reduction chamber, and the reaction chambers A to C are set as the oxidation chambers. Thereafter, at times t5 to t8, the control device 3 sequentially executes the same switching control as at times t1 to t4.

Thus, in the example shown in FIG. 2, each time the control device 3 performs switching control, one reaction chamber is switched from one side to the other side of the plurality of reaction chambers 2a arranged in one direction (see FIG. 1). 2a are sequentially set as reduction chambers, and after setting the reaction chamber 2a on the othermost side in one direction as the reduction chamber, switching control is performed so that the reaction chamber 2a on the farthest one side in one direction is again set as the reduction chamber. conduct.

That is, the control device 3 controls the switching control so that the amount of oxygen carrier particles oxidized by the oxidizing gas in the oxidation chamber becomes larger than the amount of oxygen carrier particles reduced by oxidation of the fuel in the reduction chamber. Execute switching control.

Note that the time chart shown in FIG. 2 is merely an example. When the CLC furnace has three or more reaction chambers 2a, the order of the reaction chambers 2a to be reduced chambers in each switching control executed by the control device 3 at predetermined timing can be appropriately set.

The predetermined reference for the control device 3 to determine that the oxidation of the fuel in the reduction chamber has ended may be a predetermined reference time calculated from the amount of fuel input, or a predetermined reference time indicated by a thermometer that measures the temperature in the reduction chamber. or a predetermined reference value indicated by a densitometer that measures the concentration of carbon dioxide in the second exhaust gas generated in the reduction chamber.

Further, in the present embodiment, the fuel reaction time from after switching control 1 until the oxidation of fuel in the reduction chamber is substantially completed is set so that the oxidation of oxygen carrier particles in the oxidation chamber is substantially completed after switching control 1. Longer than oxygen carrier oxidation time to finish. Therefore, the timing (t1 to t8) for switching control is matched to the fuel reaction time. However, if the oxygen carrier oxidation time is longer than the fuel reaction time, the timing of switching control may be matched with the oxygen carrier oxidation time. Also, the timing of performing the switching control may be adjusted to a longer time than either the fuel reaction time or the oxygen carrier oxidation time, whichever is longer.

Further, in the example shown in FIG. 2, each reaction chamber 2a is set to be an oxidation chamber over a plurality of (here, three) continuous switching controls. There is no real problem if chamber 2a is maintained as a reduction chamber for longer than that.

As described above, according to the CLC system 1, the switching control by the controller 3 is repeatedly executed while the oxidation chamber and the reduction chamber exist at a constant ratio. As a result, the oxidation reaction and the reduction reaction of the oxygen carrier particles can be performed at a constant rate in the reaction chambers 2a as a whole. can be kept constant. Therefore, it is possible to prevent the heat recovery amount from greatly fluctuating during operation of the CLC system 1 . In addition, since fluctuations in the amount of fuel and oxidizing gas supplied to the plurality of reaction chambers 2a as a whole can be suppressed, a supply facility for supplying fuel and oxidizing gas to the plurality of reaction chambers 2a of the present CLC system 1 can be suppressed.

In addition, the CLC system 1 is such that the switching control by the control device 3 is repeatedly executed while the oxidation chamber and the reduction chamber exist at a constant ratio. Compared to , it is superior in that pulsation in the intake system and exhaust system during operation can be eliminated. The CLC system 1 is also excellent in that it can oxidize solid fuel as well as gas fuel.

The plurality of reaction chambers 2a includes at least three or more reaction chambers 2a, and the controller 3 sets one reaction chamber 2a among the plurality of reaction chambers 2a as a reduction chamber and sets the reaction chambers other than the reduction chamber. 2a is set as the oxidation chamber, and the switching control is repeatedly performed so that each reaction chamber 2a out of the plurality of reaction chambers 2a is sequentially set as the reduction chamber.

As a result, the oxidation reaction of the oxygen carrier particles and the oxidation reaction of the fuel can be performed evenly throughout the plurality of reaction chambers 2a, and it is possible to further prevent the heat recovery amount from fluctuating significantly during operation of the CLC system 1. .

The CLC system 1 also includes a fuel gasification agent supply path R3 provided with a plurality of third supply devices 14. As an example, the fuel is solid fuel, and the control device 3 controls the plurality of supply devices 9, 13, 14 is individually controlled to fluidize the oxidized oxygen carrier particles and the solid fuel with the fuel gasifying agent in the reduction chamber at the first timing, and the oxidized oxygen carrier particles are used to fluidize the fuel gasifying agent. to oxidize the gasified solid fuel and reduce the oxygen carrier particles.

Thus, by using the fuel gasifying agent, the oxidized oxygen carrier particles and the solid fuel are efficiently fluidized in the reduction chamber, and the oxidized oxygen carrier particles are gasified by the fuel gasifying agent. Solid fuels can be oxidized.

In addition, the CLC system 1 includes a single CLC furnace 2 (furnace body) in which a plurality of reaction chambers 2a and partition walls 2b for individually partitioning the plurality of reaction chambers 2a are formed. The CLC furnace 2 can be compactly configured, the installation area of the plurality of reaction chambers 2a can be reduced, and the size of the CLC system 1 can be suppressed satisfactorily. 2a can be monitored relatively easily.

In addition, the control device 3 controls the switching control so that the amount of oxygen carrier particles oxidized by the oxidizing gas in the oxidation chamber becomes larger than the amount of oxygen carrier particles reduced by oxidation of the fuel in the reduction chamber. Since the switching control is executed, even when a gas with a relatively low oxygen concentration such as air is used as the oxidizing gas, the oxygen carrier particles reduced as the fuel is oxidized in the reducing chamber are transferred to the oxidizing gas in the oxidation chamber. can facilitate proper oxidation.

Further, by forming a plurality of reaction chambers 2a inside the CLC furnace 2, which is a single furnace body, piping for connecting each reaction chamber 2a can be omitted. Therefore, the amount of oxygen carrier particles can be reduced, and the installation area of the CLC system 1 can be suppressed by configuring a plurality of reaction chambers 2a compactly. Therefore, in the CLC system 1 including the CLC furnace 2 that oxidizes the solid fuel, it is possible to prevent an increase in the size of the facility, simplify the facility structure, and prevent a decrease in operational reliability. For this reason, the CLC system 1 can be effectively used, for example, as a small-to-medium-sized furnace for industrial power generation on a scale of small- and medium-sized industries, or as a combustion furnace for burning garbage and biomass.

In addition, since piping for connecting each reaction chamber 2a can be omitted, for example, gas to be supplied to the piping for high-speed distribution and transportation of oxygen carrier particles and control become unnecessary, and oxygen carrier particles and piping can be connected. It is possible to avoid problems such as corrosion and abrasion of the piping and pulverization of the oxygen carrier particles due to the contact between the two. Thereby, the control of the CLC system 1 can be simplified, and the CLC system 1 can be economically and stably driven. The second embodiment will be described below, focusing on differences from the first embodiment.

(Second embodiment)
FIG. 3 is a schematic diagram of the CLC system 11 according to the second embodiment. As shown in FIG. 3, the CLC furnace 12 of the second embodiment is provided with gas-permeable support members 2d for supporting the oxygen carrier particles above the fluidized bed 2c inside each of the plurality of reaction chambers 2a. there is

As an example, the support member 2d is formed in the shape of a porous plate, extends in the radial direction of the reaction chamber 2a, and is in contact with the inner surface of the reaction chamber 2a along the entire circumference of the reaction chamber 2a. Above the support member 2d, an auxiliary fluidized bed 2e containing oxygen carrier particles is provided separately from the fluidized bed 2c.

As an example, the bottom surface of the auxiliary fluidized bed 2e is arranged above the center of the reaction chamber 2a in the vertical direction. The upper surface of the auxiliary fluidized bed 2e is arranged below the upper end of the reaction chamber 2a. The maximum depth dimension of the auxiliary fluidized bed 2e is set to a value smaller than the maximum depth dimension of the fluidized bed 2c.

During operation of the CLC system 11, when the reaction chamber 2a provided with the support member 2d is set as a reduction chamber, carbon monoxide (CO ) or hydrogen (H ₂ ), the unreacted gas passes through the supporting member 2d and enters the auxiliary fluidized bed 2e. After that, the unreacted gas is oxidized by the oxygen carrier particles in the auxiliary fluidized bed 2e.

As described above, in the second embodiment, in the reduction chamber, the solid content of the fuel is oxidized in the fluidized bed 2c, and the unreacted gas of the fuel is oxidized in the auxiliary fluidized bed 2e. is done. That is, the auxiliary fluidized bed 2e functions as a volatile matter reactor.

Further, when the reaction chamber 2a provided with the supporting member 2d is set as an oxidation chamber, the oxidizing gas supplied to the oxidation chamber oxidizes both the oxidized carrier particles in the fluidized bed 2c and the auxiliary fluidized bed 2e. . By supplying the oxidizing gas from the lower side of the oxidation chamber to the oxidation chamber, the oxidation carrier particles in the fluidized bed 2c and the auxiliary fluidized bed 2e are oxidized once by the oxidizing gas flowing through the oxidation chamber from the bottom to the top. Efficiently oxidized in the process.

Also in the second embodiment, the same effect as in the first embodiment is exhibited. In the second embodiment, gas-permeable support members 2d for supporting the oxygen carrier particles above the fluidized bed 2c are provided in each of the plurality of reaction chambers 2a. Even if unreacted gas is generated in the fluidized bed 2c, the oxygen carrier particles supported by the gas-permeable support member 2d can efficiently oxidize the unreacted gas that has passed through the support member 2d. Therefore, the carbon dioxide conversion rate of the fuel can be improved, and unreacted gas can be prevented from being discharged outside the reaction chamber 2a, thereby reducing the environmental load.

In addition, since the auxiliary fluidized bed 2e composed of the support member 2d and the oxygen carrier particles supported by the support member 2d is provided above the fluidized bed 2c, it is possible to prevent the installation area of the plurality of reaction chambers 2a from increasing. The CLC system 11 can be configured at relatively low cost.

In the second embodiment, a plurality of auxiliary fluidized beds 2e may be provided at intervals in the vertical direction. Further, the auxiliary fluidized bed 2e may contain oxygen carrier particles different from the oxygen carrier particles in the fluidized bed 2c. In this case, the oxygen carrier particles contained in the auxiliary fluidized bed 2e and the oxygen carrier particles contained in the fluidized bed 2c may differ in at least one of particle size, shape, size and material.

(Third embodiment)
FIG. 4 is a schematic diagram of a CLC system 21 according to a third embodiment. The fuel of the CLC system 21 is gas fuel. In this case, since no fuel gasification agent is required, the CLC system 21 does not include the fuel gasification agent supply path R3 and the supply device 14 .

The CLC system 21 has a gas fuel supply line R6. The gas fuel supply path R6 is individually connected to the plurality of reaction chambers 2a, and is provided with a plurality of fourth supply devices 16 through which the gas fuel flows and which can individually adjust the gas fuel flow rate to each reaction chamber 2a. . The fourth supply device 16 is connected to the control device 3 and controlled by the control device 3 .

An upstream end of the gas fuel supply path R6 is connected to a pump (not shown) for taking in gas fuel from a gas fuel supply source. The downstream end of the gas fuel supply path R6 is branched, and each branched path is connected to the lower side of each reaction chamber 2a via the fourth supply device 16. As shown in FIG.

The end of the branched channel in the gas fuel supply channel R6 is further branched into a plurality of branches and connected to the lower side of each reaction chamber 2a. As a result, the gas fuel can be supplied to the reaction chamber 2a at predetermined timings from a plurality of positions below the reaction chamber 2a.

At a first timing, the control device 3 fluidizes the oxidized oxygen carrier particles with the gas fuel in the reduction chamber, oxidizes the gas fuel with the oxidized oxygen carrier particles, and reduces the oxygen carrier particles. That is, in the third embodiment, by using gas fuel, the oxygen carrier particles are fluidized by the gas fuel instead of the fuel gasifying agent.

Thus, when gas fuel is used as the fuel, the fuel gasifying agent and the fuel gasifying agent supply path R3 can be omitted. By fluidizing the carrier particles, a reduction reaction of the oxygen carrier particles can be obtained.

The present invention is not limited to each embodiment, and the configuration and method of the present invention can be changed, added, or deleted without departing from the spirit of the present invention. Each embodiment may be arbitrarily combined with each other, for example, a partial configuration in one embodiment may be applied to another embodiment. Moreover, when using solid fuel as fuel, you may use gas fuel and liquid fuel together with solid fuel.

Further, in each of the above-described embodiments, a configuration example in which a plurality of reaction chambers 2a are provided by dividing the inside of a single furnace body (CLC furnace 2) is shown, but at least one reaction chamber 2a is the remaining reaction chamber. It may be provided at a position separated from 2a. In this case, for example, each of the plurality of reaction chambers 2a may be arranged side by side at separated positions.

R1 fuel supply path R2 oxidizing gas supply path R3 fuel gasification agent supply path 1, 11, 21 chemical looping combustion system 2, 12 CLC furnace (furnace body)
2a, AD reaction chamber 2b partition wall 2c fluidized bed 2d support member 3 control device 4 first heat exchanger (heat recovery device)
5 Second heat exchanger (heat recovery device)
9 first supply device 13 second supply device 14 third supply device

Claims (6)

a plurality of reaction chambers in which fluidized beds containing oxygen carrier particles are arranged;
a fuel supply path provided with a plurality of first supply devices individually connected to the plurality of reaction chambers, through which fuel flows, and capable of individually adjusting a fuel flow rate to each of the plurality of reaction chambers;
an oxidizing gas supply path provided with a plurality of second supply devices individually connected to the plurality of reaction chambers, through which the oxidizing gas flows, and capable of individually adjusting the flow rate of the oxidizing gas to each of the reaction chambers;
a control device that controls the plurality of first and second supply devices;
a heat recovery device for recovering heat from the exhaust gas of the plurality of reaction chambers,
The control device individually controls the plurality of first and second supply devices to
At a first timing, a specific number of the reaction chambers among the plurality of reaction chambers are set as reduction chambers in which the fuel is oxidized and the oxygen carrier particles are reduced by the oxidized and fluidized oxygen carrier particles. setting the remaining reaction chamber as an oxidation chamber for oxidizing the oxygen carrier particles reduced by the oxidation of the fuel with an oxidizing gas;
At a second timing after the first timing, the reaction chamber set as the reduction chamber at the first timing is set as the oxidation chamber, and among the reaction chambers set as the oxidation chamber at the first timing, the specified repeatedly executing switching control for switching the plurality of reaction chambers while allowing the oxidation chamber and the reduction chamber to exist at a constant ratio so that the same number of reaction chambers as the number of reaction chambers are set as the reduction chamber;
the fuel is a solid fuel;
In each of the reduction chambers, the oxidized oxygen carrier particles and the solid fuel are mixed with the fuel while the fluidized bed containing the oxidized oxygen carrier particles and the solid fuel does not flow between the plurality of reaction chambers. A chemical looping combustion system fluidized by a fuel gasifier that gasifies the The plurality of reaction chambers includes at least three or more reaction chambers,
The control device sets one reaction chamber among the plurality of reaction chambers as the reduction chamber, sets the reaction chambers other than the reduction chambers as the oxidation chamber, and sequentially sets each of the reaction chambers as the reduction chamber. 2. The chemical looping combustion system according to claim 1, wherein said switching control is repeatedly executed so as to set. A fuel gasifying agent supply provided with a plurality of third supply devices individually connected to the plurality of reaction chambers, through which the fuel gasifying agent flows, and capable of individually adjusting the flow rate of the fuel gasifying agent to each of the reaction chambers. prepare more roads,
the fuel is a solid fuel;
The control device individually controls the plurality of first, second, and third supply devices so that the oxidized oxygen carrier particles and the solid fuel are produced in the reduction chamber at the first timing. is fluidized by the fuel gasifying agent to cause the oxidized oxygen carrier particles to oxidize the solid fuel gasified by the fuel gasifying agent and reduce the oxygen carrier particles. Chemical looping combustion system. Inside each of the plurality of reaction chambers, a gas-permeable support member is provided above the fluidized bed to support oxygen carrier particles different from the oxygen carrier particles contained in the fluidized bed . The chemical looping combustion system according to claim 3. The chemical looping combustion system according to any one of claims 1 to 4, comprising a single furnace body in which the plurality of reaction chambers and partition walls that individually partition the plurality of reaction chambers are formed. . The control device makes the amount of oxygen carrier particles oxidized by the oxidizing gas in the oxidation chamber greater than the amount of oxygen carrier particles reduced by oxidation of the fuel in the reduction chamber by performing the switching control once. 6. The chemical looping combustion system according to any one of claims 1 to 5, wherein said switching control is executed as follows.

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