JP2023000822A - Exhaust gas treatment facility, and power generation facility - Google Patents

Abstract

To recover CO2 at a minimum cost effectively using thermal energy of exhaust gas.SOLUTION: CO2 absorption liquid in which CO2 has been absorbed is sent to a heat recovery device 11, the CO2 absorption liquid is heated by heat of exhaust gas, CO2 is separated by gas-liquid separation means 16 using heat of the heated CO2 absorption liquid as separation power, and the CO2 absorption liquid (regenerated CO2 absorption liquid) from which CO2 has been separated is sent to a re-heating device 12. Therefore, CO2 contained in exhaust gas of combustion gas is separated from the CO2 absorption liquid by heat of the exhaust gas.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to an exhaust gas treatment facility and a power generation facility equipped with an exhaust gas treatment device.

Coal exists in a wide area of the world, has many recoverable reserves, and has a stable price. Coal is used, for example, as fuel for boilers for power generation (eg, Patent Document 1), and power generation using coal has realized a stable supply of electric power.

On the other hand, when fossil fuels are used, the current situation is that the generation of CO ₂ is unavoidable. For this reason, various attempts have been made to suppress the emission of CO ₂ by separating and recovering the CO ₂ and subjecting it to isolation treatment. When CO ₂ is separated and recovered, thermal energy such as steam for power generation is required. For CO ₂ sequestration, consideration should be given to the decrease in power generation output and handling, as well as the transportation route and storage location. I needed it.

For this reason, in the field of power generation technology, various efforts have been made to realize a stable supply of power and to reduce _CO2 emissions. At present, there is room for establishing a technology for separating and recovering CO ₂ by effectively using energy.

JP 2018-204843 A

The present invention has been made in view of the above circumstances, and provides an exhaust gas treatment facility capable of separating and recovering _CO2 at a minimum cost by effectively using energy, and a power generation facility equipped with the exhaust gas treatment facility. intended to provide

An exhaust gas treatment facility according to claim 1 for achieving the above object is provided in an exhaust gas treatment path, and includes heat recovery means for recovering heat of exhaust gas, and the exhaust gas treatment path downstream of the heat recovery means. reheating means for reheating the exhaust gas by circulating a CO ₂ absorbing liquid as a heat medium between the heat recovery means and the CO ₂ absorbing liquid directed from the reheating means to the heat recovery means. CO _{2 absorption means provided in the path between the heat recovery means and the reheating means for causing the CO 2 absorption} liquid to absorb CO ₂ in the exhaust gas in the exhaust gas treatment path between the heat recovery means and the reheating means; Regenerating means provided in the path of the CO ₂ absorbing liquid heading toward the means for regenerating the CO ₂ absorbing liquid by separating the CO ₂ absorbed by the CO ₂ absorbing liquid as a gas by the heat of the exhaust gas whose heat is recovered by the heat recovery means. and

In the present invention according to claim 1, CO ₂ in the exhaust gas is absorbed by the CO ₂ absorbing liquid of the CO ₂ absorbing means, and the CO ₂ absorbing liquid with the CO ₂ absorbed is sent to the heat recovery means. The CO ₂ absorbing liquid is heated by the heat recovery means by the heat of the exhaust gas, and the heat of the heated CO ₂ absorbing liquid becomes separation power, and the CO ₂ is separated by the regeneration means. The CO ₂ absorbent from which CO ₂ has been separated (regenerated CO ₂ absorbent) is sent to the reheating means to raise the temperature of the exhaust gas to a desired state (the temperature of the CO ₂ absorbent is lowered to a desired temperature), The CO ₂ absorbing liquid cooled to the desired temperature is circulated to the CO ₂ absorbing means.

As the CO ₂ absorbing liquid, an amine absorbing liquid such as monoethanolamine (MEA) or methyldiethanolamine (MDEA) can be used.

For this reason, even in the treatment of flue gas from combustion gas that uses carbonaceous fuel (coal) as fuel, it is possible to effectively use the thermal energy of the flue gas to separate and recover _CO2 at a minimum cost. Become.

According to claim 2 of the present invention, in the exhaust gas treatment facility of claim 1, the exhaust gas treatment facility is provided in the exhaust gas treatment path between the heat recovery means and the CO ₂ absorption means, It is characterized by comprising a dust collection means for collecting dust in the exhaust gas flowing through the route.

In the second aspect of the present invention, the CO ₂ absorption means downstream of the dust collection means absorbs CO _{2 in the exhaust gas into the CO 2 absorption} liquid. Even without a desulfurization device, it can be used for exhaust gas treatment of coal combustion gas using low-S coal. In addition, if there is a means such as in-furnace desulfurization or blowing absorbent into the flue, even if coal other than low-S coal is used, it is possible to construct an exhaust gas treatment route without a desulfurization device. .

Further, according to claim 3, in the exhaust gas treatment equipment according to claim 2, the exhaust gas treatment equipment is provided in the exhaust gas treatment path between the dust collection means and the CO ₂ absorption means, It is characterized by comprising desulfurization means for removing the sulfur content of the exhaust gas flowing through the route.

In the present invention according to claim 3, the CO ₂ absorption means downstream of the desulfurization means causes the CO ₂ in the exhaust gas to be absorbed by the CO ₂ absorption liquid.

Further, the exhaust gas treatment facility of the present invention according to claim 4 is the exhaust gas treatment facility according to any one of claims 1 to 3, wherein the exhaust gas treatment path includes a combustion gas obtained by burning a carbonaceous fuel. is sent, and in the regeneration means, _CO2 is separated as a gas from the _CO2 absorption liquid in which the _CO2 of the combustion gas generated by burning the carbonaceous fuel is absorbed.

In the present invention according to claim 4, the CO ₂ contained in the exhaust gas of the combustion gas generated by burning the carbon-based fuel is absorbed by the CO ₂ absorbing liquid, and the heat of the exhaust gas separates the CO ₂ from the CO ₂ absorbing liquid. In the treatment of flue gas from combustion gas using fuel (coal, biomass, etc.), the thermal energy of the flue gas can be effectively used to separate and recover CO ₂ at a minimum cost.

A power generation facility according to claim 5 of the present invention for achieving the above object is a combustion means for generating a high-temperature, high-pressure fluid by burning a fuel derived from a carbonaceous fuel (coal, biomass, natural gas, etc.) and a turbine that expands the high-temperature/high-pressure fluid generated by the combustion means to obtain power generation power, and the exhaust gas of the combustion means is sent to the exhaust gas treatment facility according to any one of claims 1 to 4. and

In the present invention according to claim 5, the power generation facility is provided with an exhaust gas treatment facility capable of recovering CO ₂ at a minimum cost by effectively utilizing the thermal energy of the exhaust gas of the combustion gas for power generation. can be done. The carbon-based fuel includes a fuel obtained by mixing a carbon-based fuel with a non-carbon-based fuel (hydrogen, ammonia, etc.). That is, when a carbon-based fuel is used for combustion, the carbon-based fuel can be mixed with a non-carbon-based fuel (hydrogen, ammonia, etc.) for co-combustion.

The exhaust gas treatment facility of the present invention makes it possible to effectively use the thermal energy of the exhaust gas to recover CO ₂ at a minimum cost.

In addition, the power generation facility of the present invention can be provided with an exhaust gas treatment facility capable of recovering CO ₂ at a minimum cost by effectively utilizing the thermal energy of the exhaust gas.

1 is a schematic configuration diagram of a power generation facility equipped with an exhaust gas treatment facility according to a first embodiment of the present invention; FIG. FIG. 5 is a schematic configuration diagram of a power generation facility equipped with an exhaust gas treatment facility according to a second embodiment of the present invention;

FIG. 1 shows a schematic system for explaining the overall configuration of a coal-fired power plant equipped with an exhaust gas treatment system according to a first embodiment of the present invention.

Coal-fired power generation equipment includes a boiler 1 (combustion means) in which coal (pulverized coal), which is a carbonaceous fuel, is put into a combustion chamber and burns the pulverized coal to generate high-temperature, high-pressure steam (fluid). . The steam generated by the boiler 1 is expanded by the steam turbine 2, and the steam turbine 2 is driven to operate the generator 3 to obtain electric power (obtain power generation power). The steam that has finished work in the steam turbine 2 is condensed in the condenser 4 and fed to the boiler 1 .

The carbon-based fuel is not limited to coal (pulverized coal), and it is also possible to use a fuel in which a carbon-based fuel is mixed with a non-carbon-based fuel (hydrogen or ammonia). That is, when combustion is performed using a carbonaceous fuel, it is also possible to mix a carbonaceous fuel with a non-carbonaceous fuel (hydrogen or ammonia) for co-combustion.

Exhaust gas from the boiler 1 is treated by an exhaust gas treatment facility 5 and released to the atmosphere through a chimney 10 . An exhaust gas treatment path 6 of the boiler 1 is provided with a denitrification device 7 , and exhaust gas from which NO _X has been removed by the denitrification device 7 is heat-recovered by an air heater 8 .

The exhaust gas whose heat is recovered by the air heater 8 is sent to the heat recovery device 11 (heat recovery means) of the CO ₂ treatment system that absorbs and recovers CO ₂ in the exhaust gas. A CO ₂ absorbent (for example, an aqueous amine solution) as a heat medium circulates between the heat recovery device 11 and the exhaust gas treatment path 6 on the downstream side of the heat recovery device 11 to reheat the exhaust gas (CO ₂ absorption A reheater 12 (reheating means) for cooling the liquid is provided. After cooling (reheating) the CO ₂ absorbent, the flue gas is released to the atmosphere.

That is, a circulation path 13 through which the CO ₂ absorbent circulates is constructed across the heat recovery device 11 and the reheater 12 . A circulation pump 14 is provided in the circulation path 13. By driving the circulation pump 14, the CO ₂ absorbent in the circulation path 13 circulates counterclockwise in the figure.

On the other hand, the exhaust gas treatment path 6 is provided with a CO ₂ absorbing means 15, through which the CO ₂ absorbing liquid directed from the reheater 12 to the heat recovery device 11 is circulated _{(the CO 2 absorbing} means 15 are provided in the circulation path 13). By sending the exhaust gas to the CO ₂ absorbing means 15, CO ₂ in the exhaust gas is absorbed by the CO ₂ absorbent.

A gas-liquid separation means 16 is provided in the circulation path 13 from the heat recovery device 11 to the reheater 12 . The gas-liquid separation means 16 separates the CO ₂ absorbed by the CO ₂ absorbent as a gas by the heat of the exhaust gas heat-recovered by the heat recovery device 11 to regenerate the CO ₂ absorbent (for example, the CO 2 absorbed by the aqueous amine solution). release _O2 ).

Numeral 17 in the figure is an absorbent heater for heating the CO ₂ absorbent when the heat for regenerating the CO ₂ absorbent is insufficient. Reference numeral 18 in the figure denotes a fan. The CO ₂ released from the heat recovery device 11 to the absorbent heater 17 and the gas-liquid separation means 16 is separated from the absorption liquid by the gas-liquid separation means 16 (regeneration means).

An exhaust gas treatment path 6 between the heat recovery device 11 and the CO ₂ absorbing means 15 is equipped with an electric dust collector 9 (dust collecting means) that collects dust in the exhaust gas at extremely low temperatures. The electric dust collector 9 can be installed upstream of the denitrification device 7 and downstream of the air heater 8 depending on the performance of the device (depending on the dust collecting temperature and the like).

In the power generation equipment having the above configuration, the generator 3 is driven by the steam generated in the boiler 1 to obtain electric power. Combustion exhaust gas (exhaust gas) from the boiler 1 is sent to an exhaust gas treatment path 6 to remove impurities and released to the atmosphere. That is, _NOx is removed by the denitrification device 7, dust is removed by the electrostatic precipitator 9, and _CO2 is absorbed by the _CO2 absorbing liquid of the _CO2 absorbing means 15 and removed.

Then, the CO ₂ absorbent in which CO ₂ has been absorbed is sent to the heat recovery device 11 . The CO ₂ absorbing liquid is heated by the heat of the exhaust gas (for example, 130° C.), and the heat of the heated CO ₂ absorbing liquid becomes separation power to separate CO ₂ in the gas-liquid separating means 16 . The CO ₂ absorbent (regenerated CO ₂ absorbent) from which CO ₂ has been separated by the gas-liquid separation means 16 is sent to the reheater 12, and the heat of the CO ₂ absorbent raises the temperature of the exhaust gas to a desired state. (CO ₂ absorption liquid is cooled to the desired temperature). For example, exhaust gas is heated from 50°C to 90°C. The CO ₂ absorbing liquid cooled to the desired temperature is circulated to the CO ₂ absorbing means 15 .

The CO ₂ (gas) separated by the gas-liquid separation means 16 is used for desired purposes. For example, it is used for synthesizing hydrocarbons such as methane. It is also, for example, liquefied, transported and stored, or segregated.

For this reason, even in the treatment of flue gas from combustion gas using coal as fuel (even in the treatment of flue gas for which _CO2 emissions are unavoidable), the _CO2 contained in the flue gas of the combustion gas is the heat of the flue gas. It is possible to separate and recover _{CO 2 at} a minimum cost by effectively using the thermal energy of the exhaust gas.

Although the exhaust gas treatment of the above embodiment is not provided with a desulfurization device, it can be used for the exhaust gas treatment of coal combustion gas using low-S coal. In addition, if there is a means such as in-furnace desulfurization or blowing absorbent into the flue, even if coal other than low-S coal is used as shown in the illustration, exhaust gas treatment route without desulfurization equipment can be constructed.

A second embodiment of the present invention will be described with reference to FIG. FIG. 2 shows a schematic system for explaining the overall construction of a power generation facility equipped with an exhaust gas treatment facility according to a second embodiment of the present invention.

In contrast to the system shown in FIG. 1, the exhaust gas treatment facility 20 of the _second embodiment shown in FIG. A wet desulfurization device (desulfurization means) 21 is provided for removing the sulfur content of the exhaust gas. Therefore, the desulfurization device 21 removes the sulfur content of the exhaust gas, and the CO ₂ absorption means 15 allows the CO ₂ in the exhaust gas from which the sulfur content has been removed to be absorbed by the CO ₂ absorbent.

In the above embodiments, coal was used as the carbonaceous fuel, but solid fuel such as biomass or gaseous fuel such as natural gas can also be used. It is also possible to use a mixture of carbonaceous fuel and non-carbonaceous fuel (hydrogen, ammonia, etc.). In addition, as an exhaust gas treatment equipment, it is also possible to apply it to equipment for treating exhaust gas of power generation equipment that generates power by expanding a high-temperature, high-pressure fluid generated by burning fuel in a combustor with a turbine.

INDUSTRIAL APPLICABILITY The present invention can be used in the industrial field of exhaust gas treatment equipment.

1 Boiler 2 Steam Turbine 3 Generator 4 Condenser 5, 20 Exhaust Gas Treatment Facility 6 Exhaust Gas Treatment Path 7 Denitration Device 8 Air Heater 9 Electric Precipitator 10 Chimney 11 Heat Recovery Device 12 Reheater 13 Circulation Path 14 Circulation Pump 15 CO ₂ Absorption Means 16 gas-liquid separation means 17 absorbent heater 21 desulfurization device

Claims (5)

a heat recovery means provided in the exhaust gas treatment path for recovering the heat of the exhaust gas;
a reheating means provided in the exhaust gas treatment path on the downstream side of the heat recovery means for reheating the exhaust gas by circulating a CO ₂ absorbent as a heat medium between the heat recovery means and the exhaust gas treatment path;
provided in the path of the CO ₂ absorbing solution from the reheating means to the heat recovery means, and transferring CO _{2 in the exhaust gas in the exhaust gas treatment path between the heat recovery means and the reheating means to the CO 2 absorbing} solution; a _CO2 absorption means for absorption;
The CO ₂ absorbed by the CO ₂ absorbing liquid is separated as a gas by the heat of the exhaust gas, which is provided in the path of the CO ₂ absorbing liquid heading from the heat recovery means to the reheating means, and the heat of the exhaust gas is recovered by the heat recovery means. _2. An exhaust gas treatment facility characterized by comprising regeneration means for regenerating the absorbent. In the exhaust gas treatment facility according to claim 1,
An exhaust gas treatment facility, comprising: a dust collection means provided in the exhaust gas treatment path between the heat recovery means and the CO ₂ absorption means for collecting dust in the exhaust gas flowing through the exhaust gas treatment path. In the exhaust gas treatment equipment according to claim 2,
An exhaust gas treatment facility comprising desulfurization means provided in the exhaust gas treatment path between the dust collection means and the CO ₂ absorption means for removing sulfur content from exhaust gas flowing through the exhaust gas treatment path. In the exhaust gas treatment facility according to any one of claims 1 to 3,
Exhaust gas of combustion gas generated by burning a carbonaceous fuel is sent to the exhaust gas treatment path,
The exhaust gas treatment facility, wherein the regeneration means separates CO ₂ as a gas from a CO ₂ absorbent in which the CO ₂ of the combustion gas generated by burning the carbonaceous fuel is absorbed. Combustion means for burning a fuel derived from a carbonaceous fuel to generate a high-temperature, high-pressure fluid;
a turbine that expands the high-temperature/high-pressure fluid generated by the combustion means to obtain power generation power;
A power generation facility comprising: the exhaust gas treatment facility according to any one of claims 1 to 4, to which the exhaust gas of the combustion means is sent.

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