JP2023179257A - Combustion system and exhaust gas treatment unit - Google Patents

Abstract

To easily and efficiently separate CO2 contained in gas to be treated, in a combustion system.SOLUTION: A refuse incineration facility 1, which is a combustion system, comprises: a boiler 41 that generates steam by burning fuel in a combustion chamber 11; a turbine 42 to which steam is supplied from the boiler 41; and a separation membrane module 32 that has a separation membrane containing a CO2 carrier, in which for a first space and a second space separated by the separation membrane, gas to be treated containing CO2 is supplied to the first space, and steam discharged from the turbine 42 is supplied to the second space, and that moves CO2 contained in the gas to be treated from the first space to the second space. Consequently, CO2 contained in the gas to be treated can be easily and efficiently separated.SELECTED DRAWING: Figure 1

Description

The present invention relates to combustion systems and exhaust gas treatment units.

In recent years, there has been an increasing demand for CO ₂ recovery in various facilities that generate CO ₂ (carbon dioxide), and separation and recovery of CO ₂ using separation membranes has been attracting attention. For example, in the combustion system of Patent Document 1, of a first processing chamber and a second processing chamber separated by a facilitated transport membrane that is a separation membrane, a gas to be treated containing methane gas is supplied to the first processing chamber, and a gas to be treated containing methane gas is supplied to the second processing chamber. A sweep gas containing water vapor is supplied to the processing chamber. As a result, CO ₂ in the gas to be processed selectively permeates into the second processing chamber. The water vapor in Patent Document 1 is removed from the gas that has passed through the first processing chamber, or is generated using combustion exhaust gas of methane gas contained in the gas that has passed through the first processing chamber.

Patent Document 2 discloses a method for removing CO ₂ from a mixed gas stream by passing the mixed gas stream along one side of a facilitated transport membrane and passing water vapor along the other side of the membrane. has been done. The water vapor is generated by the action of cooling exhaust gas generated from the internal combustion engine or by the action of the coolant of the internal combustion engine. The device of Patent Document 3 includes a CO ₂ separator configured to selectively permeate CO 2 contained in the CO ₂ -containing gas flowing into the first space into the second space through a separation membrane, and _a water tank. It has a water vapor supply channel that communicates a space above the water level in the water tank with a second space, and a pump that reduces the pressure of the second space. Evaporation of water inside the water tank is promoted by the reduced pressure of the pump, and water vapor is supplied to the second space.

Note that Patent Document 4 discloses a method of recovering CO ₂ from a gas to be treated discharged from a power generation plant equipped with a boiler and a steam turbine. This method includes an adsorption step of adsorbing CO ₂ from the gas to be treated using a CO ₂ adsorbent, and a desorption step of desorbing CO ₂ from the CO ₂ adsorbent that has adsorbed CO ₂ using desorption steam. will be carried out. The desorption steam is saturated steam prepared from superheated steam obtained by compressing a part of the outlet steam discharged from the steam turbine outlet.

Patent No. 6966993 Special table 2015-536814 publication JP 2021-159813 Publication Patent No. 5812694

By the way, in a combustion system having a boiler and a turbine, when separating CO ₂ from a gas to be treated containing CO ₂ such as exhaust gas using a separation membrane, it is possible to apply the methods of Patent Documents 1 to 3. . However, the methods of Patent Documents 1 to 3 require additional equipment and energy to generate water vapor to be supplied to the separation membrane. Therefore, there is a need for an approach to easily and efficiently separate _CO2 in combustion systems without requiring such additional equipment or energy. Furthermore, when the gas to be treated is exhaust gas, a method for appropriately separating CO ₂ contained in the exhaust gas is also required.

The present invention was made in view of the above problems, and aims to easily and efficiently separate _{CO 2 contained} in the gas to be treated in a combustion system. The purpose is also to properly separate the

The invention according to claim 1 is a combustion system that includes a boiler that generates steam by burning fuel in a combustion chamber, a turbine to which the steam is supplied from the boiler, and a separation system that includes a carbon dioxide carrier. Of a first space and a second space that have a membrane and are separated by the separation membrane, the first space is supplied with a gas to be treated containing carbon dioxide, and the gas that is discharged from the turbine is supplied to the second space. and a separation membrane module to which water vapor is supplied and which moves carbon dioxide contained in the gas to be treated from the first space to the second space.

The invention according to claim 2 is the combustion system according to claim 1, wherein the gas to be treated containing carbon dioxide is an exhaust gas discharged from the combustion chamber or a furnace discharged from the top of a blast furnace. It includes top gas, atmospheric air, or a mixture of gases mainly composed of hydrogen or hydrocarbons.

The invention according to claim 3 is the combustion system according to claim 1 (which may be the combustion system according to claim 1 or 2), wherein a liquid containing water is supplied to the gas to be treated. The apparatus further includes a gas cooling section that lowers the temperature of the gas to be processed.

The invention according to claim 4 is the combustion system according to claim 3, wherein the gas to be treated includes exhaust gas discharged from the combustion chamber, and the gas cooling section is configured to separate the combustion chamber from the separation gas. It is provided in the path of the exhaust gas between the membrane module, the liquid contains a drug, and a predetermined component is removed from the exhaust gas in the gas cooling section.

The invention according to claim 5 is the combustion system according to any one of claims 1 to 4, which comprises condensing carbon dioxide-containing steam discharged from the second space of the separation membrane module. The system further includes a condenser that separates water and carbon dioxide.

The invention according to claim 6 is the combustion system according to claim 5, further comprising another condenser for condensing steam discharged from the turbine and not passing through the second space of the separation membrane module. Furthermore, it is equipped with.

The invention according to claim 7 is the combustion system according to any one of claims 1 to 4 (or may be the combustion system according to any one of claims 1 to 6). , further comprising another separation membrane module that separates water from carbon dioxide-containing water vapor discharged from the second space of the separation membrane module.

The invention according to claim 8 is the combustion system according to any one of claims 1 to 4 (or may be the combustion system according to any one of claims 1 to 7). , further comprising a carbon dioxide utilization device that generates a predetermined product using carbon dioxide-containing water vapor discharged from the second space of the separation membrane module.

The invention according to claim 9 is the combustion system according to any one of claims 1 to 4 (or may be the combustion system according to any one of claims 1 to 8). , the fuel is waste, and the gas to be treated includes exhaust gas discharged from the combustion chamber.

The invention according to claim 10 is an exhaust gas treatment unit, which includes a wet smoke scrubbing tower that supplies a liquid containing water and a drug to the exhaust gas to remove a predetermined component from the exhaust gas, and lowers the temperature of the exhaust gas. , having a separation membrane containing a carbon dioxide carrier, of a first space and a second space separated by the separation membrane, the exhaust gas that has passed through the wet smoke scrubber is supplied to the first space; A separation membrane module is provided, into which water vapor is supplied and which moves carbon dioxide contained in the exhaust gas from the first space to the second space.

In the invention according to claims 1 to 9, CO ₂ contained in the gas to be treated can be easily and efficiently separated in the combustion system. In the tenth aspect of the invention, in the exhaust gas treatment, CO ₂ contained in the exhaust gas can be appropriately separated.

FIG. 1 is a block diagram showing the configuration of a garbage incineration facility according to a first embodiment. It is a sectional view showing a wet smoke scrubbing tower and a separation membrane module. It is a block diagram showing the composition of garbage incineration equipment of a first comparative example. It is a block diagram showing the composition of garbage incineration equipment concerning a 2nd embodiment. It is a block diagram showing the composition of garbage incineration equipment concerning a 3rd embodiment. It is a block diagram showing the composition of garbage incineration equipment concerning a 4th embodiment.

(First embodiment)
FIG. 1 is a block diagram showing the configuration of a garbage incineration facility 1 according to a first embodiment of the present invention. The garbage incineration facility 1 is a waste incineration facility that incinerates garbage, which is waste, and is also a combustion system that burns garbage as fuel and converts it into energy. The waste incineration equipment 1 includes a combustion chamber 11, an exhaust gas flow path 21, an economizer 22, a dust collector 23, a wet smoke scrubber 31, a separation membrane module 32, a denitrification device 24, and a chimney 25. . The combustion chamber 11 is an incinerator, and burns (incinerates) garbage input from a garbage pit (not shown). The exhaust gas passage 21 is a flue through which exhaust gas discharged from the combustion chamber 11 flows. In the example of FIG. 1, the exhaust gas passage 21 is a passage from the combustion chamber 11 to the chimney 25. The economizer 22, dust collector 23, wet smoke scrubber 31, separation membrane module 32, and denitrification device 24 are provided in the exhaust gas flow path 21, and are arranged from the upstream side to the downstream side in the flow direction of the exhaust gas (i.e., from the combustion chamber to the downstream side). 11 toward the chimney 25). In FIG. 1, the exhaust gas flow path 21 is indicated by a plurality of thick arrows, and only the arrow between the combustion chamber 11 and the economizer 22 is given the reference numeral 21 indicating the exhaust gas flow path.

The economizer 22 heats water supplied to a boiler 41 (described later) through heat exchange with exhaust gas. The dust collector 23 is a so-called bag filter, and uses a filter cloth to collect fly ash contained in the exhaust gas. A powdered exhaust gas treatment agent may be supplied to the exhaust gas on the upstream side of the dust collector 23, and the exhaust gas treatment agent may be collected together with the fly ash in the dust collector 23. Exhaust gas treatment chemicals are used to remove sulfur oxides, hydrogen chloride, dioxins, mercury compounds, etc. The exhaust gas that has passed through the dust collector 23 flows into a wet smoke scrubbing tower 31 .

FIG. 2 is a sectional view showing the wet smoke scrubbing tower 31 and the separation membrane module 32. Inside the wet smoke scrubbing tower 31, for example, at least one (in FIG. 2, a plurality of) spray sections 311 and a packed bed 312 are provided. The spray unit 311 sprays a liquid containing a predetermined medicine and water. The drug is, for example, an alkaline drug such as caustic soda. The filling layer 312 is filled with a predetermined filler. The liquid flows into the gaps between the fillers. In the example of FIG. 2, exhaust gas flows into the wet smoke scrubbing tower 31 from the lower part and flows upward. In the wet smoke scrubbing tower 31, the exhaust gas is sprayed with the liquid and passes through the gaps between the fillers. As a result, the temperature of the exhaust gas is lowered to, for example, 50° C. to 70° C., and predetermined components such as sulfur oxides and hydrogen chloride contained in the exhaust gas are removed. The exhaust gas that has reached the upper part of the wet smoke scrubbing tower 31 is discharged to the separation membrane module 32. In the wet smoke scrubbing tower 31, it is possible to remove substances that inhibit the separation of _CO2 (carbon dioxide) in the separation membrane 322, which will be described later.

The separation membrane module 32 includes, for example, an outer cylinder 321 and a separation membrane 322. The outer cylinder 321 has, for example, a cylindrical shape with a lid and a bottom, and extends in the vertical direction in FIG. 2 . The separation membrane 322 has a cylindrical shape extending in the vertical direction, and is housed inside the outer cylinder 321. The separation membrane module 32 has a first space 326 that is an internal space of the separation membrane 322 and a second space 327 that is a space between the outer peripheral surface of the separation membrane 322 and the inner peripheral surface of the outer cylinder 321. The first space 326 and the second space 327 are separated by a separation membrane 322. The separation membrane 322 is, for example, an organic polymer membrane, and operates in the presence of moisture. The separation membrane 322 is a facilitated transport membrane that contains a CO ₂ carrier such as an amine species and selectively permeates CO ₂ . The separation membrane 322 may be a membrane other than a polymer membrane as long as it operates in the presence of moisture. The _CO2 carrier may be a substance other than an amine species, such as an alkali species. The separation membrane 322 may be provided on the surface of the cylindrical porous support and placed within the outer cylinder 321. The separation membrane 322 may be of a flat membrane type, a tubular type, a hollow fiber type, a spiral type, or the like. Further, a plurality of separation membrane modules 32 may be provided in series or in parallel to the wet smoke scrubbing tower 31.

In the example of FIG. 2, the exhaust gas discharged from the wet smoke scrubbing tower 31 flows into the first space 326 from the inlet at the lower end of the separation membrane module 32, and flows upward, that is, within the wet smoke scrubbing tower 31. flows in the same direction as the direction of flow. The exhaust gas contains a large amount of water vapor by passing through the wet smoke scrubbing tower 31, and is almost saturated with water vapor. Further, as described later, water vapor containing almost no CO ₂ is supplied to the second space 327 as a sweep gas. For example, the water vapor flows into the second space 327 from an inlet at the upper end of the separation membrane module 32 and flows downward.

Here, the separation membrane 322, which is a facilitated transport membrane, needs to hold a sufficient amount of water at all times in order to increase the permeation rate of _CO2 . As described above, due to the high moisture concentration (humidity) in the first space 326 and the second space 327, the separation membrane 322 maintains a state in which a sufficient amount of water is retained. Further, the water vapor flowing into the second space 327 contains almost no CO ₂ , and the partial pressure of CO ₂ in the second space 327 is sufficiently lower than the partial pressure of CO ₂ in the first space 326 . As a result, in the first space 326, the CO ₂ contained in the exhaust gas reacts with the CO ₂ carrier of the separation membrane 322, causing sorption and diffusion of CO ₂ to the separation membrane 322. Further, in the second space 327, CO ₂ is diffused (desorbed) in the separation membrane 322, and CO ₂ is mixed with the water vapor flowing in the second space 327. In one example, the following reaction occurs in the separation membrane 322.

As described above, the separation membrane module 32 uses the exhaust gas as the gas to be processed, moves CO ₂ contained in the exhaust gas from the first space 326 to the second space 327, and separates (removes) CO ₂ from the exhaust gas. In the waste incineration facility 1, a wet smoke scrubber 31 and a separation membrane module 32 constitute an exhaust gas treatment unit 3 that removes predetermined components contained in exhaust gas and separates _CO2 . The exhaust gas after CO ₂ removal is discharged from the outlet at the upper end of the separation membrane module 32 to the outside of the first space 326 and guided to the denitrification device 24 (see FIG. 1). The water vapor mixed with CO ₂ in the second space 327 (hereinafter also referred to as "CO ₂ -containing water vapor") is discharged to the outside of the second space 327 from an outlet near the lower end of the separation membrane module 32 . The _CO2- containing water vapor discharged from the separation membrane module 32 will be described later.

In the exhaust gas treatment unit 3, if the separation membrane module 32 is placed downstream of the wet smoke scrubbing tower 31 in the flow direction of the exhaust gas, the separation membrane module 32 is placed below the wet smoke scrubbing tower 31. Often, the wet smoke scrubbing tower 31 and the separation membrane module 32 may be arranged side by side in a substantially horizontal direction. Moreover, the flow direction of exhaust gas in the first space 326 of the separation membrane module 32 and the flow direction of water vapor in the second space 327 may be the same or may be opposite. Moreover, the flow directions may intersect with each other.

The denitrification device 24 in FIG. 1 has a denitrification tower in which a denitrification catalyst is provided, and removes nitrogen oxides and the like contained in the exhaust gas. In the denitrification device 24, the exhaust gas may be reheated as necessary. The exhaust gas that has passed through the denitrification device 24 is discharged to the outside from the chimney 25.

The waste incineration facility 1 further includes a boiler 41, a turbine (steam turbine) 42, a condenser 43, a condensate tank 44, and a deaerator 45. The boiler 41 has an exhaust heat recovery section 411 that is a group of boiler tubes. In the exhaust heat recovery section 411, high temperature and high pressure steam is generated using the exhaust gas generated in the combustion chamber 11 as a heat source. In this way, in the boiler 41, water vapor is generated by burning waste in the combustion chamber 11. High pressure steam is supplied to the turbine 42. As described later, in the waste incineration equipment 1, water (steam) circulates in the order of the boiler 41, turbine 42, separation membrane module 32, condenser 43, condensate tank 44, and deaerator 45. The circulation route is indicated by a plurality of broken line arrows.

The turbine 42 generates electricity using high pressure steam. The used steam in the turbine 42 is discharged from the turbine 42 as exhaust steam. The discharged steam is low-temperature, low-pressure steam with reduced pressure. The temperature of the discharged steam is, for example, 100°C or less, and in this treatment example, it is 50°C to 70°C. In this embodiment, the steam discharged from the turbine 42 is supplied as a sweep gas to the second space 327 of the separation membrane module 32 in FIG. 2 without being heated or pressurized. The discharged water vapor may be heated, cooled, pressurized or depressurized, and then supplied to the separation membrane module 32.

The CO ₂ -containing steam flows into the condenser 43 . In the condenser 43, water contained in the _CO2- containing steam is condensed (ie, condensed) by cooling. In other words, water is removed from the _CO2- containing water vapor and concentrated _CO2 gas is obtained. The condenser 43 is provided with a gas extractor (air extractor) having a vacuum pump or the like, and CO ₂ gas can be extracted by the gas extractor. The condensed water (condensate) is sent to the condensate tank 44 and stored there. The concentrated CO ₂ gas is stored in the CO ₂ storage tank 51. The CO ₂ gas may be used to generate methane or the like in a carbon dioxide utilization device 56 (see FIG. 6), which will be described later (the same applies hereinafter). The water (liquid) in the condensate tank 44 is degassed by the deaerator 45 and then heated by the economizer 22 by heat exchange with exhaust gas. The heated water is supplied to the exhaust heat recovery section 411, and high-pressure steam is generated.

FIG. 3 is a block diagram showing the configuration of the waste incineration facility 9 of the first comparative example. In the waste incineration equipment 9 of the first comparative example, a CO ₂ recovery section 92 is provided in place of the separation membrane module 32 in FIG. The CO ₂ recovery unit 92 recovers CO ₂ by a chemical absorption method, and includes an absorption tower and a regeneration tower. In an absorption tower, a liquid containing, for example, amine and water is sprayed into the exhaust gas, and the CO ₂ is absorbed into the liquid. That is, _CO2 is removed from the exhaust gas. The liquid that has absorbed CO ₂ is sent to a regeneration tower and heated, and the CO ₂ is removed and recovered. The exhaust gas that has passed through the CO ₂ recovery section 92 is discharged to the outside from the chimney 25 via the denitrification device 24 .

Incidentally, the exhaust gas discharged from the wet smoke scrubbing tower 31 is at a high temperature, and in order to recover CO ₂ by the chemical absorption method, it is necessary to cool the exhaust gas to about 40°C. Therefore, in the _waste incineration equipment 9 of the first comparative example shown in FIG. ), the process related to CO ₂ recovery becomes inefficient. It is also possible to recover CO ₂ by an adsorption method, but in this case, a regeneration process of the adsorbent is required, and similarly, the process related to CO ₂ recovery becomes inefficient. Furthermore, in the waste incineration facility 9 of the first comparative example, the low-pressure exhaust steam discharged from the turbine 42 directly flows into the condenser 43 and is condensed. That is, the discharged steam is not used for any purpose but is condensed. Note that in the condenser 43 of the waste incineration facility 9, air and the like mixed with the discharged water vapor are released into the atmosphere.

Next, a second comparative example will be described in which, in the separation membrane module, a molecular sieve membrane (such as a zeolite membrane) that separates CO ₂ by a molecular sieving action is used instead of a facilitated transport membrane. With a molecular sieve membrane, it is possible to selectively and continuously permeate _CO2 by applying a pressure difference (driving force) on both sides of the membrane, but in the case of combustion exhaust gas, the pressure of the exhaust gas is not very high. Since it is not expensive, CO ₂ cannot be efficiently separated. Therefore, a compressor that increases the pressure of the exhaust gas and a vacuum pump that reduces the pressure on the permeate side of the molecular sieve membrane are required. Furthermore, in the presence of moisture, it becomes difficult for CO ₂ to permeate, so a mechanism for dehumidifying the exhaust gas is also required.

On the other hand, the waste incineration facility 1 of FIG. 1 is provided with a separation membrane module 32 having a separation membrane 322 containing a CO ₂ carrier. Of the first space 326 and second space 327 separated by the separation membrane 322, exhaust gas containing CO ₂ is supplied to the first space 326, and water vapor discharged from the turbine 42 is supplied to the second space 327. Supplied. Thereby, in the separation membrane module 32, it becomes possible to move CO ₂ contained in the exhaust gas from the first space 326 to the second space 327 and separate CO ₂ from the exhaust gas. In this way, the waste incineration facility 1 does not use the gas cooling unit 91 in the first comparative example, and utilizes the water vapor discharged from the turbine 42 (i.e., discharged water vapor), which is not used in the first comparative example. Therefore, CO ₂ contained in exhaust gas can be easily and efficiently separated. Furthermore, the compressor or vacuum pump in the second comparative example is not required, and the mechanism for dehumidifying exhaust gas is also not required, so it is possible to save energy and reduce the manufacturing cost of the waste incineration equipment 1. Note that depending on the design of the waste incineration facility 1, the discharged steam may include extracted steam discharged from the turbine 42.

Preferably, the waste incineration facility 1 includes a wet smoke scrubbing tower 31 provided in an exhaust gas path between the combustion chamber 11 and the separation membrane module 32. The wet smoke scrubbing tower 31 serves as a gas cooling unit and lowers the temperature of the exhaust gas by supplying a liquid containing water to the exhaust gas. This prevents or suppresses damage to the separation membrane 322 caused by high-temperature exhaust gas, increases the amount of moisture in the exhaust gas, and makes it possible to efficiently separate CO ₂ in the separation membrane 322. More preferably, the liquid contains a chemical, so that the predetermined components can be appropriately removed from the exhaust gas while lowering the temperature of the exhaust gas in the gas cooling section (wet smoke scrubbing tower 31). As a result, it is possible to prevent or suppress the separation of CO ₂ in the separation membrane 322 from being inhibited by the component.

Preferably, a condenser 43 is provided in the water circulation path for driving the turbine 42, and the condenser 43 condenses the _CO2- containing steam discharged from the second space 327 of the separation membrane module 32. water and CO ₂ are separated. Thereby, CO ₂ contained in the CO ₂ -containing water vapor can be easily recovered.

The exhaust gas treatment unit 3 in FIG. 1 includes the wet smoke scrubbing tower 31 that supplies liquid containing water and chemicals to the exhaust gas to remove predetermined components from the exhaust gas and lowers the temperature of the exhaust gas, and a separation unit that includes a CO ₂ carrier. The separation membrane module 32 has a membrane 322 and separates CO ₂ contained in exhaust gas. Thereby, it is possible to prevent or suppress damage to the separation membrane 322 caused by high-temperature exhaust gas and inhibition of CO ₂ separation due to the relevant components in the exhaust gas, and to easily increase the amount of water in the exhaust gas. As a result, CO ₂ contained in the exhaust gas can be appropriately separated.

(Second embodiment)
FIG. 4 is a block diagram showing the configuration of a garbage incineration facility 1 according to a second embodiment of the present invention. In the waste incineration facility 1 of FIG. 4, a CO ₂ recovery condenser 52 is added compared to the waste incineration facility 1 of FIG. 1. The other configurations are the same as those in FIG. 1, and the same components are denoted by the same reference numerals.

In the waste incineration facility 1 in FIG. 4, part of the exhaust steam discharged from the turbine 42 is supplied to the second space 327 (see FIG. 2) of the separation membrane module 32, and the remaining exhaust steam flows into the condenser 43. do. In the second space 327, CO ₂ is mixed with the discharged water vapor, and the CO ₂ -containing water vapor is discharged from the second space 327 . The CO ₂ -containing water vapor flows into the CO ₂ recovery condenser 52 . In the CO ₂ recovery condenser 52, water contained in the CO ₂ -containing water vapor is condensed by cooling, and concentrated CO ₂ gas is obtained. Condensed water (condensate) is drained outside. The water may be sent to the condensate tank 44. The concentrated CO ₂ gas is stored in the CO ₂ storage tank 51. Exhaust steam flowing into the condenser 43 from the turbine 42 is condensed, and air and the like mixed with the exhaust steam are released into the atmosphere.

As described above, the waste incineration facility 1 of FIG. 4 is provided with the condenser 43 and the CO ₂ recovery condenser 52. In the CO ₂ recovery condenser 52 , CO ₂ -containing water vapor discharged from the second space 327 of the separation membrane module 32 is condensed. In the condenser 43, water vapor discharged from the turbine 42 and not passing through the second space 327 of the separation membrane module 32 is condensed. In this way, by providing a condenser exclusively for CO ₂ recovery (CO ₂ recovery condenser 52), CO ₂ contained in CO ₂ -containing water vapor can be easily recovered. Furthermore, it is possible to prevent exhaust gas components from affecting the water used in the boiler and turbine.

(Third embodiment)
FIG. 5 is a block diagram showing the configuration of a garbage incineration facility 1 according to a third embodiment of the present invention. In the waste incineration facility 1 of FIG. 5, a water separation membrane module 53 is added compared to the waste incineration facility 1 of FIG. 1. The other configurations are the same as those in FIG. 1, and the same components are denoted by the same reference numerals.

In the waste incineration equipment 1 shown in FIG. 5, like the waste incineration equipment 1 shown in FIG. It flows into the condenser 43. In the second space 327, CO ₂ is mixed with the discharged water vapor, and the CO ₂ -containing water vapor is discharged from the second space 327 . The CO ₂ -containing water vapor flows into the water separation membrane module 53 . The water separation membrane module 53 includes, for example, a hydrophilic water separation membrane. In the water separation membrane, water vapor contained in the CO ₂ -containing water vapor is separated, and concentrated CO ₂ gas is obtained. The separated water vapor flows into the condenser 43 and is condensed. The concentrated CO ₂ gas is stored in the CO ₂ storage tank 51.

As described above, in the waste incineration facility 1 shown in _FIG . provided. Thereby, high concentration CO ₂ can be easily recovered from CO ₂ -containing water vapor. In addition, the boiler/turbine system can be operated without losing steam.

(Fourth embodiment)
FIG. 6 is a block diagram showing the configuration of a garbage incineration facility 1 according to a fourth embodiment of the present invention. In the waste incineration facility 1 of FIG. 6, a hydrogen gas mixer 54 is provided in place of the CO ₂ recovery condenser 52 in the waste incineration facility 1 of FIG. The other configurations are the same as those in FIG. 4, and the same configurations are denoted by the same reference numerals.

CO ₂ -containing water vapor flows into the hydrogen gas mixer 54 from the separation membrane module 32 . In the hydrogen gas mixer 54, hydrogen gas is mixed with _CO2- containing steam, and the _CO2- containing steam is brought to normal pressure. Further, in the hydrogen gas mixer 54, water contained in the _CO2- containing steam is condensed. The gas containing hydrogen and CO ₂ is sent to the methane gas generation section 55, and methane gas is generated by methanation. In this way, the hydrogen gas mixer 54 and the methane gas generation unit 55 are a carbon dioxide utilization device 56 that generates methane gas using CO ₂ -containing water vapor. Water condensed in the hydrogen gas mixer 54 (condensate) is drained to the outside. The water may be sent to the condensate tank 44. In the carbon dioxide utilization device 56, processes other than methanation may be performed, and products other than methane gas may be generated.

As described above, the waste incineration facility 1 of FIG. 6 is provided with a carbon dioxide utilization device 56 that generates a predetermined product using CO ₂ -containing water vapor discharged from the second space 327 of the separation membrane module 32. . This makes it possible to efficiently utilize CO ₂ contained in the exhaust gas.

Various modifications can be made to the waste incineration facility 1 and the exhaust gas treatment unit 3.

In the waste incineration facility 1, a combustion system is realized with the boiler 41, the turbine 42, and the separation membrane module 32 as the main components, but the combustion system may also be used for purposes other than waste incineration, such as thermal power generation. good. The fuel burned in the combustion chamber 11 may be fossil fuel, carbon neutral fuel (CN fuel), etc. in addition to waste. The gas to be treated from which CO ₂ is separated may be a gas other than the exhaust gas discharged from the combustion chamber 11, and may be two or more types of gas including a gas supplied from the outside. For example, the gas to be treated containing CO ₂ may be top gas discharged from the top of a blast furnace, air in the atmosphere (DAC: Direct Air Capture), or a mixed gas containing hydrogen or hydrocarbons as its main component ( shift reaction gas, biogas, etc.). In either case, the combustion system described above can easily and efficiently separate CO ₂ contained in the gas to be treated. On the other hand, a preferred embodiment of the combustion system is a waste incineration facility 1, in which the fuel burned in the combustion chamber 11 is waste, and the gas to be treated includes exhaust gas discharged from the combustion chamber 11.

In the waste incineration facility 1, the wet smoke scrubbing tower 31 may be omitted, and a cooling tower that sprays a liquid containing water (which does not need to contain an alkaline chemical) to the exhaust gas may be provided as the gas cooling section. When the gas to be treated is other than exhaust gas, a gas cooling unit may be provided that lowers the temperature of the gas to be treated by supplying a liquid containing water to the gas to be treated. Depending on the temperature of the gas to be processed, the gas cooling section may be omitted.

The _CO2- containing water vapor discharged from the second space 327 of the separation membrane module 32 does not necessarily need to be condensed, and may be used as _CO2- containing water vapor in the carbon dioxide utilization device 56, for example.

The configurations of the above embodiment and each modification may be combined as appropriate unless mutually contradictory.

1 Garbage incineration equipment 3 Exhaust gas treatment unit 11 Combustion chamber 31 Wet smoke scrubbing tower 32 Separation membrane module 41 Boiler 42 Turbine 43 Condenser 52 Condenser for CO ₂ recovery 53 Water separation membrane module 56 Carbon dioxide utilization device 322 Separation membrane 326 1st space 327 2nd space

Claims (10)

A combustion system,
a boiler that generates steam by burning fuel in a combustion chamber;
a turbine to which the steam is supplied from the boiler;
It has a separation membrane containing a carbon dioxide carrier, and of a first space and a second space separated by the separation membrane, the first space is supplied with a gas to be treated containing carbon dioxide, and the second space is supplied with the gas to be treated, and the gas containing carbon dioxide is supplied to the second space. a separation membrane module to which the water vapor discharged from the turbine is supplied and which moves carbon dioxide contained in the gas to be treated from the first space to the second space;
A combustion system characterized by comprising: The combustion system according to claim 1, comprising:
The gas to be treated containing carbon dioxide is exhaust gas discharged from the combustion chamber, top gas discharged from the top of a blast furnace, air in the atmosphere, or a mixed gas containing hydrogen or hydrocarbon as a main component. A combustion system comprising: The combustion system according to claim 1, comprising:
A combustion system further comprising a gas cooling unit that lowers the temperature of the gas to be treated by supplying a liquid containing water to the gas to be treated. 4. The combustion system according to claim 3,
The gas to be treated includes exhaust gas discharged from the combustion chamber,
The gas cooling unit is provided in the exhaust gas path between the combustion chamber and the separation membrane module,
A combustion system characterized in that the liquid contains a drug, and a predetermined component is removed from the exhaust gas in the gas cooling section. A combustion system according to any one of claims 1 to 4, comprising:
A combustion system further comprising a condenser that separates water and carbon dioxide by condensing carbon dioxide-containing water vapor discharged from the second space of the separation membrane module. The combustion system according to claim 5,
A combustion system further comprising another condenser for condensing steam discharged from the turbine and not passing through the second space of the separation membrane module. A combustion system according to any one of claims 1 to 4, comprising:
A combustion system further comprising another separation membrane module that separates water from carbon dioxide-containing water vapor discharged from the second space of the separation membrane module. A combustion system according to any one of claims 1 to 4, comprising:
A combustion system further comprising a carbon dioxide utilization device that generates a predetermined product using carbon dioxide-containing water vapor discharged from the second space of the separation membrane module. A combustion system according to any one of claims 1 to 4, comprising:
A combustion system characterized in that the fuel is waste, and the gas to be treated includes exhaust gas discharged from the combustion chamber. An exhaust gas treatment unit,
a wet smoke scrubbing tower that supplies a liquid containing water and chemicals to the exhaust gas to remove predetermined components from the exhaust gas and lower the temperature of the exhaust gas;
It has a separation membrane containing a carbon dioxide carrier, and among a first space and a second space separated by the separation membrane, the exhaust gas that has passed through the wet smoke scrubber is supplied to the first space, and the second space a separation membrane module to which water vapor is supplied and which moves carbon dioxide contained in the exhaust gas from the first space to the second space;
An exhaust gas treatment unit characterized by comprising:

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