WO2011105176A1 - Chemical loop reaction system and power generation system using same - Google Patents

Chemical loop reaction system and power generation system using same Download PDF

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Publication number
WO2011105176A1
WO2011105176A1 PCT/JP2011/051977 JP2011051977W WO2011105176A1 WO 2011105176 A1 WO2011105176 A1 WO 2011105176A1 JP 2011051977 W JP2011051977 W JP 2011051977W WO 2011105176 A1 WO2011105176 A1 WO 2011105176A1
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Prior art keywords
reactor
air
exhaust gas
temperature
oxidation
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PCT/JP2011/051977
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French (fr)
Japanese (ja)
Inventor
研二 山本
雅人 半田
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株式会社日立製作所
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Priority to JP2010041249A priority Critical patent/JP5501029B2/en
Priority to JP2010-041249 priority
Application filed by 株式会社日立製作所 filed Critical 株式会社日立製作所
Publication of WO2011105176A1 publication Critical patent/WO2011105176A1/en

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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22STEAM GENERATION
    • F22BMETHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B35/00Control systems for steam boilers
    • F22B35/06Control systems for steam boilers for steam boilers of forced-flow type
    • F22B35/08Control systems for steam boilers for steam boilers of forced-flow type of forced-circulation type
    • F22B35/083Control systems for steam boilers for steam boilers of forced-flow type of forced-circulation type without drum, i.e. without hot water storage in the boiler
    • F22B35/086Control systems for steam boilers for steam boilers of forced-flow type of forced-circulation type without drum, i.e. without hot water storage in the boiler operating at critical or supercritical pressure
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00Carbon; Compounds thereof
    • C01B32/50Carbon dioxide
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01KSTEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K7/00Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating
    • F01K7/16Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating the engines being only of turbine type
    • F01K7/22Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating the engines being only of turbine type the turbines having inter-stage steam heating
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22STEAM GENERATION
    • F22BMETHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00Methods of steam generation characterised by form of heating method
    • F22B1/22Methods of steam generation characterised by form of heating method using combustion under pressure substantially exceeding atmospheric pressure
    • Y02E20/326
    • Y02E20/344
    • Y02P20/124

Abstract

A chemical loop reaction system comprises: an oxidation reactor which reacts substances with oxygen, if oxygen is present, to form oxides, and if oxygen is not present but hydrocarbon compounds are present, uses an oxidation medium which is reduced to discharge oxygen, and reacts the oxygen and the oxidation medium; and a regeneration reactor which reacts the oxidized oxidation medium with a fuel having a hydrocarbon as its major constituent. The chemical loop reaction system also has a return path for returning the oxidation medium, which has passed through the regeneration reactor, to the oxidation reactor. By supplying air to the oxidation reactor and supplying air gas with a reduced oxygen concentration emitted from the oxidation reactor to a heat exchanger and an exhaust gas treatment device, the energy of the exhaust gas is recovered efficiently, and the exhaust gas is purified efficiently.

Description

Chemical loop reaction system and power generation system using the same

The present invention relates to a reaction system used in a thermal power plant and a power generation system.

A boiler device, which is a combustion plant provided in a power plant or the like, generates water by heating water with heat generated by burning fuel and air and driving a steam turbine to generate electricity. The boiler device can use many kinds of fuels, but it is less efficient than the gas turbine combined cycle power generation device and emits a large amount of carbon dioxide. Carbon dioxide is considered to be a cause of global warming, and it is required to separate and collect the carbon dioxide generated by the combustion of the boiler and store it so as not to diffuse into the atmosphere.

In the power generation system that separates and collects carbon dioxide, there are an air combustion method that burns fuel and air, an oxyfuel combustion method that burns oxygen separated from the fuel and air, and a chemical loop method. In the air combustion method, the main components of the exhaust gas after combustion are nitrogen and carbon dioxide, and high energy is required to separate carbon dioxide therefrom. On the other hand, in the oxyfuel combustion method, most of the product gas generated by combustion is carbon dioxide, so that the energy for separating carbon dioxide from the exhaust gas is low. In the chemical loop system, the reaction medium is oxidized with air in one of the reactors (reactor 1), and the reaction medium oxidized in another reactor (reactor 2) reacts with the fuel. By returning the reaction medium reduced by the reaction with the fuel to the reactor 1 again, the reaction medium is circulated. The main product of reactor 2 is carbon dioxide. The chemical loop does not use oxygen and has a low separation energy of carbon dioxide from the exhaust gas, so there is a possibility that a highly efficient power generation system can be realized.

Further, as described in Non-Patent Document 1, a method using a metal oxide as a reaction medium has been proposed.

Yan Cao and Wei-Ping Pan, Investment of Chemical Looping Combustion by Solid Fuels. 1. Process Analysis, Energy & Fuels 2006, 20, pp.1836-1844

In a power generation system that can separate and recover carbon dioxide using a chemical loop, compared to other methods such as an air combustion method and an oxyfuel combustion method, there are many reactors, and thus efficient heat recovery is difficult. Further, although there are two reactors, no exhaust gas purification method corresponding to each exhaust gas has been proposed.

The present invention aims at efficiently recovering heat and efficiently purifying exhaust gas in a reaction system / power generation system capable of separating and recovering carbon dioxide using a chemical loop.

The present invention uses an oxidation medium that reacts with oxygen in the presence of oxygen to form an oxide, and is reduced and releases oxygen in the presence of a hydrocarbon compound without oxygen, and the oxygen, the oxidation medium, And an oxidation reactor for reacting the oxidized oxidation medium with a fuel containing hydrocarbon as a main component, and the oxidation reactor for the oxidation medium that has passed through the regeneration reactor. In a chemical loop reaction system having a return path to the air, air is supplied to the oxidation reactor, and air gas having a reduced oxygen concentration discharged from the oxidation reactor is supplied to a heat exchanger and an exhaust gas treatment device. Features.

Furthermore, in the above chemical loop reaction system, an air / air gas heat exchanger for exchanging heat between the air supplied to the oxidation reactor and the air gas is used as the heat exchanger.

Furthermore, in the above chemical loop reaction system, a structure in which the air gas discharged from the oxidation reactor is passed in the order of a high temperature heat exchanger, a high temperature exhaust gas treatment device, the air / gas heat exchanger, and a low temperature exhaust gas treatment device. Have.

Also, a heat transfer tube is installed in the oxidation reactor or on the wall.

Further, water is sprayed on the air.

In the chemical loop reaction system, a heat exchanger and a cleaning device for the oxidation medium are installed in the middle of the return path.

In the chemical loop reaction system, the gas and oxygen discharged from the regeneration reactor are supplied to the exhaust gas treatment reactor, and the gas is completely burned.

Furthermore, in the chemical loop power generation system that uses the chemical loop reaction system to generate power by rotating a steam turbine and a generator using steam generated in a heat transfer tube for generating steam, the heat transfer tube is connected to the oxidation reactor and the It is characterized by being installed in a regeneration reactor.

Further, in a chemical loop power generation system that uses a chemical loop reaction system to generate power by rotating a steam turbine and a generator using steam generated in a heat transfer pipe for steam generation, the heat transfer pipe is connected to the oxidation reactor and the regeneration. It is installed in the reactor.

Further, in the chemical loop power generation system, gas and oxygen discharged from the regeneration reactor are supplied to the exhaust gas treatment reactor, the gas is completely burned, and heat is generated between the exhaust gas after combustion and low-temperature carbon dioxide. It is provided with a heat exchanger for exchanging, and a device for supplying carbon dioxide with an increased temperature to the regeneration reactor or the exhaust gas treatment reactor.

Furthermore, in the chemical loop power generation system, an exhaust gas treatment device is installed in the exhaust gas flow path after heat exchange with low temperature carbon dioxide.

According to the present invention, in a reaction system / power generation system capable of separating and recovering carbon dioxide using a chemical loop, a heat exchanger and an exhaust gas treatment device are installed downstream of an oxidation reactor to efficiently generate heat generated by combustion. It is possible to improve the power generation efficiency by recovering the exhaust gas and to reduce NOx, SOx, ash, etc. contained in the exhaust gas.

1 is a flow diagram of a chemical loop reaction system of Example 1. FIG. 3 is another flow diagram of the chemical loop reaction system of Example 1. FIG. 3 is another flow diagram of the chemical loop reaction system of Example 1. FIG. 3 is another flow diagram of the chemical loop reaction system of Example 1. FIG. 3 is another flow diagram of the chemical loop reaction system of Example 1. FIG. 3 is another flow diagram of the chemical loop reaction system of Example 1. FIG. It is a flowchart of the chemical loop power generation system of Example 2. It is another flowchart of the chemical loop power generation system of Example 2. It is another flowchart of the chemical loop power generation system of Example 2. It is another flowchart of the chemical loop power generation system of Example 2.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Descriptions of the same reference numerals are omitted because they have the same functions.

FIG. 1 shows Example 1 of a reaction system using a chemical loop. The reaction system 33 using the chemical loop includes two reaction devices. In the oxidation reactor 1, the oxidation medium 34 is supplied from the oxidation medium transfer line 10. Further, air is supplied from the air supply device 2. As the material of the oxidation medium 34, a metal material using Ni, Fe, Cu, or Cr can be used. Before being supplied to the oxidation reactor 1, the oxidation medium 34 has been reduced and is ready to react with oxygen. By mixing the oxidizing medium 34 and air, oxygen and the oxidizing medium react. For example, in the case of Ni, the following reaction (formula 1) occurs.

Reaction (Formula 1): Ni + 0.5O 2 → NiO
In general, the higher the temperature, the higher the oxidation reaction rate. By controlling the heat generated by the reaction and controlling the reaction temperature, it is possible to avoid the possibility that the temperature of the oxidation reactor 1 exceeds the heat resistance temperature and is damaged. In particular, when the temperature is about 1100 ° C. or higher, the possibility that the ash in the fuel melts and forms a lump when the fuel is cooled and the reactor is blocked is avoided. The maximum allowable temperature is related to the melting temperature of ash and is determined by the properties of ash contained in the fuel used. Further, when the temperature of the oxidation reactor 1 is lowered, the amount of oxidation reaction is reduced, the amount of oxygen supplied to the regeneration reactor 6 described later is lowered, and the output of the reaction system may be lowered. From the above, it is preferable to control the supply amount and temperature of the oxidation medium / air so that the temperature of the oxidation reactor 1 is about 1000 ° C.

The oxidation medium 34 discharged from the oxidation reactor 1 moves to the regeneration reactor 6 through the oxidation medium transfer line 7. Fuel is supplied to the regeneration reactor 6 from a fuel supply device 8. As the fuel, fossil fuels such as coal, oil and natural gas mainly composed of hydrocarbons and biomass fuels can be used. In the regeneration reactor 6, the fuel and the oxidation medium 34 are reacted. For example, when the fuel is methane and the oxidation medium is NiO, the following reaction (formula 2) occurs.

Reaction (Formula 2): 4NiO + CH 4 → 4Ni + CO 2 + 2H 2 O
That is, after the reaction, reduced oxidation medium 34 and CO 2 and H 2 O are generated. The oxidation medium 34 produced by the reaction is solid, and CO 2 and H 2 O are gases, so that separation is easy. After being separated, the oxidation medium 34 is returned to the oxidation reactor 1 through the oxidation medium transfer line 10. The gas generated by the reaction is supplied to the exhaust gas treatment device 12 with a CO 2 recovery function through the exhaust gas transfer line 11. The main components of the gas are CO 2 and H 2 O. If the gas temperature is set to 100 ° C. or lower, H 2 O can be recovered as a liquid. Since most components of the remaining gas are CO 2 , it is easy to separate and collect CO 2 . The gas may contain a small amount of S compound, N compound, hydrocarbon, soot, ash, heavy metal, and the like. For this reason, it is preferable that the exhaust gas treatment apparatus 12 with the CO 2 recovery function has a function of removing these gas components. Further, the gas may contain unburned components such as CO and char. When oxygen is insufficient, oxygen for complete combustion is supplied, and when the temperature is low, combustion efficiency can be increased by increasing the combustion temperature.

The air supplied from the air supply device 2 is discharged from the gas discharge line 3 after the reaction in the oxidation reactor 1. Since oxygen in the air and the oxidizing medium 34 react, the oxygen concentration of the exhausted gas decreases. This exhausted gas is called air gas. The main components of the air gas are nitrogen and oxygen that has not reacted with the oxidizing medium 34. In the regeneration reactor 6, the oxidizing medium 34 and the gas are separated, but it has been found that it is difficult to separate only the oxidizing medium 34 100%. Since the regeneration reactor 6 is in an oxygen-deficient state, soot is generated. It is difficult to separate the soot adhering to the oxidizing medium 34. For this purpose, soot is supplied to the oxidation reactor 1 together with the oxidation medium 34. This soot is oxidized in the oxidation reactor 1 to generate CO 2 and CO. When solid fuel such as coal is used, not only soot but also unburned fuel such as char may adhere to the oxidation medium 34 and be supplied to the oxidation reactor 1. Since the components of char are C (carbon), H (hydrogen), O (oxygen), N (nitrogen), and S (sulfur), when oxidized in the oxidation reactor 1, NOx, SOx, H 2 O, CO 2 , Environmentally hazardous substances such as CO and VOC are generated. Furthermore, char contains ash, and ash is also included in the air gas.

In order to practically operate the reaction system of the present embodiment, it is necessary to remove NOx, SOx, H 2 O, CO 2 , CO, VOC, and ash contained in the air gas and reduce them to an environmental regulation value or less. . Since the temperature of the oxidation reactor 1 is about 1000 ° C., the temperature of the air gas discharged from the oxidation reactor 1 is also increased to the same extent. It is more efficient to purify the gas at a low temperature than to purify the gas at a high temperature, and the apparatus can be simplified. However, since there is an optimum purification temperature depending on each composition, there is a possibility that it cannot be efficiently purified if the temperature is too low. It is preferable to install the heat exchanger 4 downstream of the gas discharge line 3, appropriately control the temperature, and install the exhaust gas treatment device 16 downstream of the heat exchanger 4. For example, to reduce CO, a catalyst that reacts CO with oxygen can be used. The type of catalyst may be appropriately selected according to the outlet gas temperature of the heat exchanger 4. As the exhaust gas treatment device, a denitration device, a desulfurization device, a CO removal device, an electric dust collector or filter for removing ash may be installed.

The heat exchanger 4 is supplied with a heat exchange medium from a heat exchange medium supply device 9 to recover heat. As the heat exchange medium, air, steam, water, exhaust gas and the like are suitable. An exhaust device 5 such as a chimney is installed downstream of the gas that has passed through the exhaust gas treatment device 16.

FIG. 2 shows another example of the first embodiment. In this embodiment, an example in which air from the air supply device 2 is used as a medium from the heat exchange medium supply device 9 of FIG. The configuration of the same reference numerals is the same as that described above. Thereby, the air inlet temperature of an oxidation reactor can be raised efficiently. And the temperature of an oxidation reactor can be made high. Heat is recovered by exchanging heat between the air supplied to the heat exchanger 4 by the air supply device 2 and the air gas discharged from the oxidation reactor 1. For example, assuming that the specific heat of air and air gas is the same, the gas temperature satisfies the following relationship.

m a / m ag = (T ag, in −T ag, out ) / (T a, out −T a, in )
Here, m a , m ag , T a, out , T a, in , T ag, in , T ag, out are the air mass flow rate,
These are the mass flow rate of the air gas, the outlet temperature of the air heat exchanger 4, the inlet temperature of the air, the inlet temperature of the air gas, and the outlet temperature of the air gas heat exchanger 4. m a / m ag is the ratio of air to air gas, and is 1 when oxygen in the air does not react in the oxidation reactor 1, and 1 / 0.768 = 1 when all oxygen in the air reacts. It becomes about 3. For example, assuming that m a / m ag is 1.2, T a, in is 30 ° C., T ag, in is 1000 ° C., the heat transfer surface of the countercurrent heat exchanger is T a, out is 800 ° C. In this design, T ag, out is 76 ° C. Thus, the outlet temperature of the air gas can be lowered, and the heat recovery efficiency can be increased.

The air gas contains environmental load substances such as NOx, SOx, H 2 O, CO 2 , CO, VOC, and ash. When the exhaust gas treatment device 16 is provided downstream of the air gas system of the heat exchanger 4, good. Since the gas temperature is low, environmentally hazardous substances can be efficiently removed.

FIG. 3 shows another example of the first embodiment. This is an example in which a plurality of exhaust gas treatment apparatuses are installed. As a result, the exhaust gas treatment device can be arranged for each temperature and the exhaust gas can be treated efficiently. In this example, the air gas discharged from the oxidation reactor 1 is supplied to the high temperature heat exchanger 14. In the high temperature heat exchanger 14, heat is exchanged between the steam supplied from the steam supply device 17 and the air gas. In power generation boiler facilities, it is necessary to generate steam at a high temperature of about 600 ° C. The high temperature air supplied to the high temperature heat exchanger 14 is suitable for generating this high temperature steam since the temperature is high.

The temperature of the air gas that has passed through the high-temperature heat exchanger 14 has decreased, and the air gas is supplied to the exhaust gas treatment device 18a. In the treatment of environmentally hazardous substances, there is a temperature suitable for treatment with each substance.

For example, there are two methods for removing NOx. One is a denitration method using a catalyst and ammonia. Depending on the type of catalyst, the optimum temperature for this process is 200-400 ° C. The other is a method in which ammonia is sprayed onto a gas without using a catalyst. The optimum temperature of this method is about 800 to 1000 ° C. It is preferable to adjust the heat transfer amount of the high-temperature heat exchanger 14 so that the temperature range is suitable for the method of removing NOx.

There is a method of using a catalyst suitable for operation at a high temperature even when reducing CO and VOC contained in oxygen gas. Depending on the type of catalyst and the type of gas contained in the VOC, the exhaust gas treatment device 18a may be installed in the range of 100 ° C to 400 ° C.

In addition, in order to remove SOx contained in oxygen gas, a dry desulfurization apparatus that can operate at a high temperature (for example, 150 to 300 ° C.) can be installed.

Next, the air gas that has passed through the exhaust gas treatment device 18 a is supplied to the low-temperature heat exchanger 15. With this heat exchanger, heat is exchanged between the low-temperature air supplied from the air supply device 2 and the air gas. The temperature of the air gas after leaving the low-temperature heat exchanger 15 becomes low. This low-temperature air gas is supplied to the exhaust gas treatment device 18b. Since the temperature is low, an exhaust gas treatment device that operates at a low temperature may be installed. For example, an electrostatic precipitator or filter used for collecting ash has high performance even at low temperatures, so it should be installed in this location. In addition, a wet desulfurization apparatus that operates at a low temperature can be installed.

By making the temperature of the air gas 100 ° C. or lower, water can be recovered as a liquid. There are many methods for separating and recovering CO 2 contained in gas. For example, a chemical absorption method can be used.

FIG. 4 shows another example of the first embodiment. This is an example of heat recovery using steam in the oxidation reactor 1. Thereby, the temperature of the oxidation reactor can be controlled. Moreover, steam can be obtained using a heat transfer tube. In this example, a heat exchanger 19 is installed in the oxidation reactor 1. The reaction of the oxidizing medium with oxygen is an exothermic reaction. A heat exchanger 19 is used so that the temperature of the oxidation reactor 1 does not become too high. Steam may be supplied to the heat exchanger 19. The temperature of the oxidation reactor 1 is about 1000 ° C., which is suitable for heating steam of about 400 to 600 ° C. When the heat exchanger 19 is installed inside the oxidation reactor 1, a countercurrent type and a cocurrent type can be used. In the case of the counterflow type, heat transfer efficiency can be increased. In the case of the parallel flow type, although the efficiency is low, the temperature of the air gas is lowered at a position where the temperature of the steam is high, so that the life of the heat exchanger 19 can be extended. Further, if the outer wall of the oxidation reactor 1 is configured by the heat exchanger 19, heat radiation is reduced and thermal efficiency is increased.

FIG. 5 shows another example of the first embodiment. In this example, water is mixed with air in advance to control the temperature of the oxidation reactor 1. The water supplied from the water supply device 28 is supplied to the high-temperature air supply line 13 using the water spray device 25 to control the temperature of the oxidation reactor 1. If more water is added, the air flow rate increases and the specific heat increases, so that the temperature of the oxidation reactor 1 decreases. The water spray device 25 supplies water to the three water spray lines 35. The temperature of the air gas can be controlled by adjusting the flow rate of the water spray line 35.

For example, in the following, assuming that the water spray amount is the same, the case where the water spray line 35a is used from the most upstream side and the case where the most downstream water spray line 35c is used are compared. When the water spray line 35a is used, the temperature of the air in the heat exchanger 14 and the heat exchanger 15 becomes low, so that the amount of heat transfer increases. If the temperature of the oxidation reactor 1 is controlled to a constant value, the air gas temperature in the gas discharge line 3 is the same. As a result, the temperature of the exhaust gas treatment device 26b and the exhaust gas treatment device 26c can be lowered. On the contrary, when the water spray line 35c is used, the temperature of the air in the heat exchanger 14 and the heat exchanger 15 is increased, so that the heat transfer amount of these heat exchangers is reduced. As a result, the temperature of the exhaust gas treatment devices 26b and 26c can be increased. By adjusting the flow rates of the water spray line 35a, water spray line 35b, and water spray line 35c in the same manner, the temperatures of the exhaust gas treatment devices 26b and 26c can be controlled. In order to control the temperature of the exhaust gas treatment device 26a, the temperature of the oxidation reaction device 1 may be controlled.

FIG. 6 shows another example of the first embodiment. In this example, the temperature of the oxidation medium is lowered and moved after cleaning. The oxidation medium 34 flowing through the oxidation medium transfer line 10 is cooled by the heat exchanger 32. The heat of the oxidation medium is recovered by the steam supplied from the steam supply device 17. Further, heat is exchanged with air by the heat exchanger 29 to cool. After cooling, the oxidizing medium 34 is cleaned by the cleaning device 30. Rather than cleaning at a high temperature, cleaning after cooling lowers the cost of the cleaning apparatus and simplifies the apparatus.

As impurities adhering to the oxidation medium 34, char, ash, soot, etc. are conceivable. If the temperature of the cleaning device 30 is set to 100 ° C. or lower, the cleaning can be performed using water. If the temperature of the cleaning device 30 is 100 ° C. or higher, an impurity removal method using steam or nitrogen is used. In these cases, it is possible to use an impurity separation method using a jet, a separation method based on a difference in specific gravity, and a separation method using magnetic force. Nitrogen may be used by branching air gas having a low oxygen concentration and a high nitrogen concentration downstream of the gas discharge line 3.

The oxidation medium 34 having a lowered temperature after washing and the high-temperature air that has passed through the heat exchanger 29 are reacted in the oxidation reactor 1. The oxidation medium 34 has been cleaned, but a small amount of impurities may remain. For this reason, the air gas may contain environmentally hazardous substances such as NOx, SOx, H 2 O, CO 2 , CO, VOC, and ash. In order to remove these environmentally hazardous substances, an exhaust gas treatment device 16 may be installed.

FIG. 7 shows an example of the chemical loop power generation system 140 relating to the second embodiment. This is provided with two reactors. In the oxidation reactor 101, the oxidation medium 141 is supplied from the oxidation medium transport line 110. Further, air is supplied from the air supply device 102 via the high temperature air supply line 113. In the oxidation reactor 101, oxygen in the air and the oxidation medium react. For this reason, the oxygen concentration in air gas falls.

The temperature of the air gas discharged from the oxidation reactor 101 through the gas discharge line 103 is approximately the same as that of the oxidation reactor 101. When the temperature of the oxidation reactor 101 is set to about 1000 ° C. in order to increase the oxidation reaction rate, the temperature of the air gas is also heated to about 1000 ° C. Two heat exchangers are installed to recover this heat. First, steam is heated by air gas using the heat exchanger 121. A partition wall 122 is installed inside the heat exchanger, and the air gas is divided into two systems. In order to adjust the distribution of the two systems, parallel dampers 123 and 124 are installed. The flow rate of air gas in the system with the damper closed is reduced. Steam pipes 142 and 143 are installed in each system. The amount of heat transferred to the steam pipes 142 and 143 can be adjusted by adjusting the amount of gas with a parallel damper. For example, when the parallel damper 123 is opened and the parallel damper 124 is closed, the heat transfer amount of the steam pipe 142 increases, and conversely, the heat transfer amount of the steam pipe 143 decreases.

The air gas that has passed through the heat exchanger 121 and has fallen in temperature is supplied to the second heat exchanger 114. Here, heat exchange is performed between air and air gas. The air gas discharged from the heat exchanger 114 is supplied to the exhaust gas treatment device 116. Here, the environmentally hazardous substance contained in the gas is removed and the exhaust device 105 exhausts it to the atmosphere.

In such a system, considering the heat recovery and removal of environmentally hazardous substances, the temperature should be controlled as shown below. The outlet of the heat exchanger 121 is set to about 350 ° C., and a nitrogen oxide removing device (not shown) is installed between the heat exchanger 121 and the heat exchanger 114 to remove NOx. At this temperature, the denitration catalyst operates efficiently. Next, the outlet temperature of the heat exchanger 114 is controlled to be about 100 ° C. to 200 ° C. At this temperature, air gas is supplied to the exhaust gas treatment device 116. The exhaust gas treatment device 116 is provided with an electric dust collector and a desulfurization device, and removes ash and SOx. Thereafter, the exhaust device 105 is used to release air gas to the atmosphere.

The oxidation medium 141 that has passed through the oxidation reactor 101 is oxidized, passes through the oxidation medium transfer line 107, and is supplied to the regeneration reactor 106. Here, the oxidation medium 141 reacts with the fuel supplied from the fuel supply device 108 and is reduced. The oxidation medium 141 is supplied again to the oxidation reactor 101 via the oxidation medium transfer line 110.

The gas generated in the regeneration reactor 106 is supplied to the exhaust gas treatment reactor 119 via the exhaust gas transfer line 111. The main components of the gas are CO 2 , CO, and H 2 O. However, NOx and SOx produced by reaction of N and S in the fuel and nitrogen mixed in due to air leakage are also included. In addition, solids such as ash and soot are also included. Therefore, first, the combustible material is completely burned by supplying oxygen to the exhaust gas treatment reactor 119 using the oxygen supply device 125. By setting the combustion temperature to 1500 ° C. or lower, the generation of thermal NOx can be lowered. If the gas temperature is too high, carbon dioxide may be mixed and burned.

Next, the exhaust gas is supplied to the heat exchanger 126 via the exhaust gas transfer line 111. Thereafter, the exhaust gas treatment device 116 is supplied. In the exhaust gas treatment device 116, environmental load substances are removed. Finally, CO 2 is separated and recovered by the CO 2 recovery device 139. In the exhaust gas treatment device 116 and the CO 2 recovery device 139, the efficiency may be higher at low temperatures, so the gas temperature is lowered using the heat exchanger 126. As the heat exchange medium supplies the CO 2 from the CO 2 supply device 120. In this example, CO 2 whose temperature has been increased is supplied to the regeneration reactor 106. This recovers heat.

Next, I will explain the steam system. Although the case of a one-stage reheat type, supercritical pressure recirculation boiler will be described, it can be similarly realized even in the case of a drum boiler and a subcritical pressure boiler. High-pressure water supplied from the water supply pump 130 is supplied to the steam pipe 142 of the heat exchanger 121. Water is heated by heat transfer with air gas. If the amount of heat transfer is large, the water may become steam on the way. There is no phase change when operating at supercritical pressure. The steam pipe used in this system can be a counterflow type or a cocurrent type. If you want to increase heat transfer efficiency, use a counter-current type. If you want to increase reliability, use a co-current type.

Next, the steam is supplied to the steam pipe 136 of the oxidation reactor 101. After heating, it is supplied to the steam pipe 137 of the regeneration reactor 106. Steam discharged from the steam pipe 137 is supplied to the high-pressure turbine 127. The high pressure turbine inlet temperature must be controlled within a temperature range to enhance performance and reliability. For example, 600 ° C. ± 5 ° C. The low-pressure steam flowing out from the high-pressure turbine is supplied to the steam pipe 143 of the heat exchanger 121. Further, it is heated in the exhaust gas treatment reactor 119 and supplied to the intermediate / low pressure turbine 128. Steam discharged from the intermediate / low pressure turbine is guided to the condenser 129 and supplied to the water supply pump 130 again. Although not shown, the steam turbine is equipped with a generator, which converts rotational energy into electrical energy.

In order to control the inlet steam temperature of the steam turbine, the following method may be used.
(High-pressure turbine inlet steam temperature)
When the inlet steam temperature of the high-pressure turbine is higher than the indicated value, low-temperature water may be introduced using a spray installed in the middle, or the heat transfer amount of the steam pipe 142, the steam pipe 136, and the steam pipe 137 may be reduced. . A case where the spray 144a is installed between the steam pipe 142 and the steam pipe 136 and a case where the spray 144b is installed between the steam pipe 136 and the steam pipe 137 are conceivable. If the steam temperature is high, increase the spray flow rate.

Also, the following methods can be considered to reduce the amount of heat transfer.

A) The air flow rate and the fuel flow rate are reduced, and the temperatures of the oxidation reactor 101 and the regeneration reactor 106 are lowered. As the temperature decreases, the amount of heat transfer also decreases.

B) Slow down the circulation speed of the oxidation medium 141. The oxidant is not supplied to the regeneration reactor 106, the temperature of the regeneration reactor is lowered, and as a result, the amount of heat transfer is lowered.

c) increasing the amount of supplied CO 2 from CO 2 supply device 120, to lower the temperature of the regeneration reactor 106.

D) By closing the parallel damper 123, the heat transfer amount of the steam pipe 142 is reduced.

In order to increase the inlet steam temperature of the high-pressure turbine, an operation opposite to the decrease may be performed.
(Medium and low pressure turbine inlet steam temperature)
When the inlet steam temperature of the intermediate / low pressure turbine is higher than the indicated value, low temperature water may be added using a spray installed in the middle or the heat transfer amount of the steam pipe 138 and the steam pipe 143 may be reduced. For example, the spray 144c may be installed between the heat transfer tube 143 and the heat transfer tube 138. In order to reduce the amount of heat transfer, the following method may be used.

A) The amount of oxygen supplied from the oxygen supply device 125 is adjusted, and the temperature of the exhaust gas treatment reactor 119 is lowered. In general, when the amount of oxygen is increased, the temperature of the exhaust gas treatment reactor 119 increases, and the amount of heat transfer in the steam pipe 138 increases.

b) CO 2 reduces the supply amount of CO 2 from the supply device 120. The temperature of the regeneration reactor 106 rises, and unburned combustible material flowing to the exhaust gas treatment reactor 119 decreases. As a result, the gas temperature of the exhaust gas treatment reactor 119 decreases, and the heat transfer amount of the steam pipe 138 decreases.

C) The parallel damper 124 is closed and the heat transfer amount of the steam pipe 143 is reduced.

In the chemical loop power generation system 140 described in the above example, the steam pipe is connected so that the steam supplied to the high-pressure turbine flows in the order of the heat exchanger 121, the oxidation reactor 101, and the regeneration reactor 106. The order of the heat exchanger 121, the regeneration reactor 106, and the oxidation reactor 101 may be the order of the oxidation reactor 101, the regeneration reactor 106, and the heat exchanger 121. When steam is flowed in the order of low temperature, the heat transfer efficiency increases. In order to increase the load change rate, it is preferable to install a heat exchanger 121 that can easily change the amount of heat transfer immediately before the steam turbine.

As described above, the gas and oxygen discharged from the regeneration reactor are supplied to the exhaust gas treatment reactor, and the combustibles remaining in the air gas discharged from the regeneration reactor are removed by burning the gas. can do. Further, by installing heat transfer tubes in the oxidation reactor and the regeneration reactor, steam can be obtained using the heat transfer tubes, and power can be generated by a generator.

FIG. 8 shows another example of the chemical loop power generation system 140 according to the second embodiment. This power generation system is similar to the chemical loop power generation system described with reference to FIG. 7, but is devised for exhaust gas / air / air gas heat recovery and exhaust gas treatment methods. Here, a different part from FIG. 7 is demonstrated in detail.

In the example of FIG. 7, it has been found that in order to recover all the exhaust heat with the heat exchanger 126, it may be necessary to supply a large amount of CO 2 from the CO 2 supply device 120. When the heat exchanger 114b is used in addition to the heat exchanger 126, the amount of heat to be recovered by the heat exchanger 126 is reduced, so that the CO 2 supply amount can also be reduced. The exhaust gas exiting the exhaust gas treatment reactor 119 passes through the heat exchanger 126, and the temperature decreases. Thereafter, the environmentally hazardous substance is removed by the exhaust gas treatment device 112a. For example, the heat exchanger 126 may be adjusted so that the temperature of the exhaust gas treatment device 112a is 300 ° C. to 400 ° C., and a denitration device that can efficiently remove NOx at this temperature may be installed in the exhaust gas treatment device 112a. The exhaust gas that has passed through the heat exchanger 114b exchanges heat with the air supplied from the air supply device 102, and the temperature further decreases. Thereafter, the components not removed by the exhaust gas treatment device 112a are removed by the exhaust gas treatment device 112b. Here, the gas temperature is low, and a desulfurization device, an electrostatic precipitator, a water removal device, etc. may be installed. Finally, the hot water generator 117 performs heat exchange between the water supplied from the water supply device 118 and the exhaust gas. Water can be heated with this heat to make hot water.

The air supplied from the air supply device 102 is heated by exchanging heat with air gas in the heat exchanger 114b. Air reacts with the oxidation medium 141 in the oxidation reactor 101, and the oxygen concentration in the air decreases. The air gas exiting the oxidation reactor 101 is heated to the same level as the temperature of the oxidation reactor 101. Air gas and steam exchange heat with the heat exchanger 114a, and the temperature of the air gas decreases. Next, the air gas exchanges heat with air in the heat exchanger 114b, and the temperature is lowered. Thereafter, the exhaust gas is discharged into the atmosphere by the exhaust device 105 via the exhaust gas treatment device 116.

FIG. 9 shows another example of the chemical loop power generation system 140 according to the second embodiment of the present invention. In this example, a part of the gas of the exhaust gas treatment device 116 is supplied to the heat exchanger 126 using the CO 2 return line 131 and heated, and the regeneration reactor 106 and the exhaust gas are supplied by the CO 2 return lines 132, 133 and 134. CO 2 is fed to the treatment reactor 119. A flow rate adjusting valve is installed in the CO 2 return line, and the amount of CO 2 supplied to the regeneration reactor 106 and the exhaust gas treatment reactor 119 can be adjusted. In FIG. 9, the flow rate adjustment valve 135 is installed in the CO 2 return line 134, but the same effect can be obtained by installing it in the CO 2 return line 133. The CO 2 recovers heat in the heat exchanger 126 and controls the heat transfer amount of the steam pipe 137 installed in the regeneration reactor 106 and the steam pipe 138 installed in the exhaust gas treatment reactor 119. For example, if the flow rate of the CO 2 return line 134 is increased and the flow rate of the CO 2 return line 133 is decreased, the gas temperature of the regeneration reactor 106 decreases and the amount of unburned fuel flowing to the exhaust gas treatment reactor 119 increases. To do. Since the gas temperature of the regeneration reactor 106 decreases, the heat transfer amount of the steam pipe 106 decreases. Further, since the unburned portion increases, the amount of combustion in the exhaust gas treatment reactor 119 increases, and the amount of heat transfer in the steam pipe 138 increases. Thus, the amount of heat transfer to the steam and the steam temperature can be controlled by changing the place where CO 2 is introduced. Further, as described above, by having the return pipe 131 that supplies CO 2 to the heat exchanger 126, the heat transfer amount and temperature of the heat exchanger 126 can be controlled.

FIG. 10 shows another example of the chemical loop power generation system 140 according to the second embodiment. In this example, two steam pipes 137 a and 138 b are installed in the regeneration reactor 106. By setting it as such a system, the inlet temperature of a medium-low pressure turbine can be made higher than the Example shown in FIG.

In addition, this invention is not limited to the above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

In the above-described example, the purpose is to efficiently recover heat and efficiently purify the exhaust gas. However, as an independent purpose, a system that excludes unnecessary system configurations regardless of the purpose, and can do.

Further, in the above-described example, control may be performed by a person operating a valve, or a control device having a CPU and a memory is provided, information is input from a measurement target, It can also be controlled by outputting commands. The processing means as a function of the control device is a program module, and each function can be implemented by reading the module and causing the computer to execute it. Each function can be implemented by causing a computer to read a recording medium on which a program module is recorded.

DESCRIPTION OF SYMBOLS 1,101: Oxidation reactor, 2,102: Air supply device, 3,103: Gas discharge line, 4, 19, 21, 29, 32, 114, 121, 126: Heat exchanger, 5,105: Exhaust device 6, 106: regeneration reactor, 7, 10, 31, 107, 110: oxidation medium transfer line, 8, 108: fuel supply device, 9: heat exchange medium supply device, 11, 111: exhaust gas transfer line, 12: Exhaust gas treatment device with CO 2 recovery function, 13, 113: High temperature air supply line, 14: High temperature heat exchanger, 15: Low temperature heat exchanger, 16, 18, 26, 112, 116: Exhaust gas treatment device, 17: Steam supply device, 20: CO 2, 22, 122: partition wall, 23,24,123,124: parallel damper, 25: water spray apparatus, 27: water supply line, 28,118: water supply device, 30: cleaning device, 33 Chemical loop reactor system, 34,141: oxidizing medium, 35: water spray line, 117: hot water generator, 119: exhaust gas treatment reactor, 120: CO 2 supply device, 125: oxygen supply apparatus, 127: high-pressure turbine, 128 : Medium-low pressure turbine, 129: Condenser, 130: Feed water pump, 131, 132, 133, 134: CO 2 return line, 135: Flow control valve, 136, 137, 138, 142, 143: Steam pipe, 139: CO 2 recovery device, 140: chemical loop power generation system, 144: spray.

Claims (10)

  1. In the presence of oxygen, it reacts with oxygen to form an oxide, and in the presence of a hydrocarbon compound without oxygen, an oxidation medium that is reduced and releases oxygen is used to react the oxygen with the oxidation medium. A return path of the oxidation medium that has passed through the regeneration reactor to the oxidation reactor, the reactor having a reactor, and a regeneration reactor that reacts the oxidized oxidation medium with a fuel mainly composed of hydrocarbons In a chemical loop reaction system having
    A chemical loop reaction system characterized in that air is supplied to the oxidation reactor, and air gas having a reduced oxygen concentration discharged from the oxidation reactor is supplied to a heat exchanger and an exhaust gas treatment device.
  2. 2. The chemical loop reaction system according to claim 1, wherein an air / air gas heat exchanger for exchanging heat between the air supplied to the oxidation reactor and the air gas is used as the heat exchanger. Chemical loop reaction system.
  3. 3. The chemical loop reaction system according to claim 2, wherein the air gas discharged from the oxidation reactor is passed in the order of a high temperature heat exchanger, a high temperature exhaust gas treatment device, the air / gas heat exchanger, and a low temperature exhaust gas treatment device. A characteristic chemical loop reaction system.
  4. 2. The chemical loop reaction system according to claim 1, wherein a heat transfer tube is installed inside or on the wall of the oxidation reactor.
  5. 3. The chemical loop reaction system according to claim 2, wherein water is sprayed on the air.
  6. 2. The chemical loop reaction system according to claim 1, wherein a heat exchanger and a cleaning device for the oxidizing medium are installed in the middle of the return path.
  7. 2. The chemical loop reaction system according to claim 1, wherein the gas and oxygen discharged from the regeneration reactor are supplied to the exhaust gas treatment reactor, and the gas is combusted.
  8. A chemical loop power generation system that uses the chemical loop reaction system according to claim 1 to generate power by rotating a steam turbine and a generator using steam generated by a heat generation tube for generating steam, wherein the heat transfer tube is connected to the oxidation reactor and the oxidation reactor. A chemical loop power generation system that is installed in a regenerative reactor.
  9. 8. The chemical loop power generation system according to claim 8, wherein the gas and oxygen discharged from the regeneration reactor are supplied to the exhaust gas treatment reactor, the gas is combusted, and heat is generated between the exhaust gas after combustion and low-temperature carbon dioxide. A chemical loop power generation system comprising a heat exchanger for exchanging, and a device for supplying carbon dioxide having an increased temperature to the regeneration reactor or the exhaust gas treatment reactor.
  10. The chemical loop power generation system according to claim 9, wherein an exhaust gas treatment device is installed in a flow path of the exhaust gas after heat exchange with low temperature carbon dioxide, and carbon dioxide discharged from the exhaust gas treatment device is used as the low temperature carbon dioxide. A chemical loop power generation system comprising a return pipe for supplying to a heat exchanger.
PCT/JP2011/051977 2010-02-26 2011-02-01 Chemical loop reaction system and power generation system using same WO2011105176A1 (en)

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JP5872337B2 (en) * 2012-03-14 2016-03-01 東京瓦斯株式会社 Chemical loop combustion apparatus and method of operating the same
US8753108B2 (en) * 2012-03-30 2014-06-17 Alstom Technology Ltd Method and apparatus for treatment of unburnts

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JP2000213371A (en) * 1999-01-25 2000-08-02 Hitachi Ltd Gas turbine generating method and generating apparatus
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JP2007270700A (en) * 2006-03-31 2007-10-18 Hitachi Ltd Combined cycle plant having intake air cooling device and its operating method and control method
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JP2000213371A (en) * 1999-01-25 2000-08-02 Hitachi Ltd Gas turbine generating method and generating apparatus
JP2000335903A (en) * 1999-04-13 2000-12-05 Boc Group Inc:The Partial oxidation of hydrocarbon
US20030024853A1 (en) * 2001-07-31 2003-02-06 Lyon Richard K. Method for efficient and environmentally clean utilization of solid fuels
JP2007270700A (en) * 2006-03-31 2007-10-18 Hitachi Ltd Combined cycle plant having intake air cooling device and its operating method and control method
WO2009013647A2 (en) * 2007-07-20 2009-01-29 Foster Wheeler Energy Corporation Method of and a plant for combusting carbonaceous fuel by using a solid oxygen carrier

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