CN116392927A - Carbon dioxide trapping and processing integrated method for flue gas discharged by natural gas boiler - Google Patents
Carbon dioxide trapping and processing integrated method for flue gas discharged by natural gas boiler Download PDFInfo
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- CN116392927A CN116392927A CN202310303926.7A CN202310303926A CN116392927A CN 116392927 A CN116392927 A CN 116392927A CN 202310303926 A CN202310303926 A CN 202310303926A CN 116392927 A CN116392927 A CN 116392927A
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- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims abstract description 278
- 229910002092 carbon dioxide Inorganic materials 0.000 title claims abstract description 139
- 239000001569 carbon dioxide Substances 0.000 title claims abstract description 135
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 106
- 238000000034 method Methods 0.000 title claims abstract description 49
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 41
- 239000003546 flue gas Substances 0.000 title claims abstract description 41
- 239000003345 natural gas Substances 0.000 title claims abstract description 27
- 238000012545 processing Methods 0.000 title claims abstract description 15
- 239000007788 liquid Substances 0.000 claims abstract description 173
- 238000005984 hydrogenation reaction Methods 0.000 claims abstract description 137
- 238000003795 desorption Methods 0.000 claims abstract description 103
- 238000010521 absorption reaction Methods 0.000 claims abstract description 99
- 239000007789 gas Substances 0.000 claims abstract description 83
- 239000002250 absorbent Substances 0.000 claims abstract description 32
- 230000002745 absorbent Effects 0.000 claims abstract description 32
- 238000006243 chemical reaction Methods 0.000 claims abstract description 30
- 230000008929 regeneration Effects 0.000 claims abstract description 28
- 238000011069 regeneration method Methods 0.000 claims abstract description 28
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000001257 hydrogen Substances 0.000 claims abstract description 14
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 14
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- 150000001875 compounds Chemical class 0.000 description 5
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- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 4
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- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
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- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1493—Selection of liquid materials for use as absorbents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
- B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1425—Regeneration of liquid absorbents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1456—Removing acid components
- B01D53/1475—Removing carbon dioxide
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- B01D—SEPARATION
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- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1456—Removing acid components
- B01D53/1481—Removing sulfur dioxide or sulfur trioxide
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- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
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- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
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- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
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- B01D53/78—Liquid phase processes with gas-liquid contact
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
- C07C1/02—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon
- C07C1/12—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon from carbon dioxide with hydrogen
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- B01D2252/20—Organic absorbents
- B01D2252/204—Amines
- B01D2252/2041—Diamines
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- B01D2252/20—Organic absorbents
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- B01D2252/20478—Alkanolamines
- B01D2252/20484—Alkanolamines with one hydroxyl group
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- B01D2258/00—Sources of waste gases
- B01D2258/02—Other waste gases
- B01D2258/0283—Flue gases
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- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02C20/00—Capture or disposal of greenhouse gases
- Y02C20/40—Capture or disposal of greenhouse gases of CO2
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Abstract
The invention belongs to the field of carbon dioxide resource utilization, and discloses a carbon dioxide capturing and processing integrated method for flue gas discharged by a natural gas boiler, which comprises the following steps: the flue gas is desulfurized and alkali washed and then enters an absorption tower, an absorbent is adopted for absorbing to obtain rich liquid, and the absorbent adopted in the absorption tower is MEA-PEHA solution with the concentration ratio of 5:5; the rich liquid enters a carbon dioxide subsequent collection procedure or enters a carbon dioxide trapping hydrogenation methane preparation integrated reaction procedure; the collection procedure: the rich liquid is regenerated in a regeneration tower to obtain lean liquid, and the lean liquid enters an absorption tower, and the rich liquid exchanges heat with the lean liquid; integrated reaction procedure: the rich liquid is desorbed in the desorption hydrogenation integrated tower after passing through the heat exchanger, and the liquid separated by the gas-liquid separator is subjected to heat exchange with the absorbent which flows out of the absorption tower and absorbs carbon dioxide and then enters the absorption tower for absorption; the separated gas and hydrogen are mixed and then enter a desorption hydrogenation integrated tower and a hydrogenation reaction tower. The device has the advantages of high systemization degree and low energy consumption.
Description
Technical Field
The invention belongs to the field of carbon dioxide resource utilization, and particularly relates to a carbon dioxide capturing and processing integrated method for flue gas discharged by a natural gas boiler.
Background
The description of the background art to which the present invention pertains is merely for illustrating and facilitating understanding of the summary of the invention, and should not be construed as an explicit recognition or presumption by the applicant that the applicant regards the prior art as the filing date of the first filed application.
The capturing and recycling treatment of carbon dioxide in the flue gas is always a focus of social attention, the concentration of carbon dioxide in the flue gas is low, the carbon dioxide is absorbed by the absorbent, and meanwhile, the high-concentration carbon dioxide and hydrogen are mixed to prepare methane, so that the method is a mode of the current recycling treatment of carbon dioxide, however, the current recycling treatment mode generally has the defects of high production cost and high system energy consumption.
Disclosure of Invention
The embodiment of the invention aims to provide a carbon dioxide trapping and processing integrated method for flue gas discharged by a natural gas boiler.
The aim of the embodiment of the invention is realized by the following technical scheme:
an integrated method for capturing and processing carbon dioxide in flue gas discharged by a natural gas boiler, comprising the following steps:
the flue gas is desulfurized and alkali washed and then enters an absorption tower, an absorbent is adopted for absorbing to obtain rich liquid, and the absorbent adopted in the absorption tower is MEA-PEHA solution with the concentration ratio of 5:5;
the rich liquid enters a carbon dioxide subsequent collection procedure or enters a carbon dioxide trapping hydrogenation methane preparation integrated reaction procedure;
the subsequent carbon dioxide collection procedure comprises the following steps:
the rich liquid is regenerated in a regeneration tower to obtain lean liquid, and the lean liquid enters an absorption tower, and the rich liquid and the lean liquid exchange heat; the carbon dioxide gas is obtained after the gas exhausted from the regeneration tower is subjected to gas-liquid separation; the carbon dioxide gas is collected after precooling, compression, adsorption, drying, condensation and purification;
the integrated reaction procedure for preparing methane by carbon dioxide trapping hydrogenation comprises the following steps:
the rich liquid is desorbed in the desorption hydrogenation integrated tower after passing through a heat exchanger, and the liquid separated by a gas-liquid separator is subjected to heat exchange with the absorbent which flows out of the absorption tower and absorbs carbon dioxide after passing through the heat exchanger, and then enters the absorption tower again for absorbing carbon dioxide;
the gas separated in the gas-liquid separator is mixed with hydrogen and then enters a desorption hydrogenation integrated tower and a hydrogenation reaction tower;
the air inlet of the hydrogenation reaction tower is connected with a pressure regulating valve.
Furthermore, the carbon dioxide trapping hydrogenation methane preparation integrated reaction procedure is completed by adopting a carbon dioxide trapping hydrogenation methane preparation integrated reaction device, and the carbon dioxide trapping hydrogenation methane preparation integrated reaction device comprises an absorption tower, a desorption hydrogenation integrated tower and a hydrogenation reaction tower;
the carbon dioxide-absorbed absorbent in the absorption tower is desorbed in the desorption hydrogenation integrated tower after passing through the heat exchanger, and the liquid separated by the gas-liquid separator is subjected to heat exchange with the carbon dioxide-absorbed absorbent flowing out of the absorption tower after passing through the heat exchanger, and then enters the absorption tower again for carbon dioxide absorption;
the gas separated in the gas-liquid separator is mixed with hydrogen and then enters a desorption hydrogenation integrated tower and a hydrogenation reaction tower;
the air inlet of the hydrogenation reaction tower is connected with a pressure regulating valve.
Further, a spraying device for spraying and absorbing solvent is arranged in the absorption tower;
the liquid outlet of the absorption tower is connected with the cold side inlet of the heat exchanger in series through a pipeline, and the cold side outlet of the heat exchanger is connected with the liquid inlet of the desorption hydrogenation integrated tower through a pipeline;
the liquid outlet of the desorption hydrogenation integrated tower is connected with a gas-liquid separator, the liquid outlet of the gas-liquid separator is connected with the hot side inlet of the heat exchanger in series through a pipeline, and the hot side outlet of the heat exchanger is connected with the liquid inlet of the absorption tower through a pipeline;
the gas outlet of the gas-liquid separator is connected with the gas mixing tank through a pipeline; the gas outlet of the gas mixing tank is connected with the compressor through a pipeline; the compressor is connected with the air inlet of the desorption hydrogenation integrated tower and the air inlet of the hydrogenation reaction tower in parallel through pipelines; the desorption hydrogenation integrated tower is a shell-and-tube type, carbon dioxide and hydrogen are introduced into the tube side, a rich liquid is introduced into the shell side, and the flow heat exchange mode can be countercurrent or concurrent; at least one carbon dioxide hydrogenation catalyst is filled in a heat exchange tube bundle of the desorption hydrogenation integrated tower; the heat exchange tube bundle of the desorption hydrogenation integrated tower is in the form of a light tube or an inner fin tube.
Furthermore, the desorption hydrogenation integrated tower is provided with at least one hydrogenation reaction tower, the inlets of the desorption hydrogenation integrated tower and the hydrogenation reaction tower are connected with a gas mixing tank through a pipeline, and the inlet reactant flow of the two towers is distributed through a pressure regulating valve.
Furthermore, the tube side and the shell side of the desorption hydrogenation integrated tower are provided with thermometers.
Furthermore, the lean solution desorbed by the desorption hydrogenation integrated tower transfers heat to the rich solution after the absorption tower absorbs CO through the heat exchanger.
Further, a CH concentration measuring instrument is arranged on an air outlet of the desorption hydrogenation integrated tower. The gas outlet of the gas-liquid separator is connected with a gas mixing tank through a connecting pipeline, and a flowmeter 9 is arranged on the connecting pipeline to obtain CO 2 Flow rate to control H entering the gas mixing tank 6 2 Flow rate.
Further, the subsequent collection procedure of the carbon dioxide is completed by adopting a carbon dioxide trapping and absorbing device suitable for the flue gas discharged by the natural gas boiler, and the carbon dioxide trapping and absorbing device suitable for the flue gas discharged by the natural gas boiler comprises a desulfurizing device, an alkaline washing tower, an absorbing tower and a regenerating tower which are communicated in sequence; the front end of the desulfurizing device is communicated with the flue;
the rich liquid outlet of the absorption tower is communicated with the liquid inlet of the regeneration tower through a first pipeline; the liquid outlet of the regeneration tower is communicated with the lean liquid inlet of the absorption tower through a second pipeline; the first pipeline and the second pipeline exchange heat through a lean-rich liquid heat exchanger; the air outlet of the regeneration tower is communicated with the gas-liquid separator.
Further, a gas outlet is arranged on the absorption tower and is communicated with the flue; the second pipeline is provided with a lean solution cooler; the subsequent carbon dioxide collecting procedure adopts a carbon dioxide capturing and absorbing device suitable for the flue gas discharged by a natural gas boiler and further comprises a solution reboiler, wherein the solution reboiler is communicated with a regeneration tower through a circulating pipeline; the subsequent collection procedure of the carbon dioxide adopts a carbon dioxide capturing and absorbing device suitable for the flue gas discharged by a natural gas boiler and further comprises a carbon dioxide treatment device, and the carbon dioxide treatment device is communicated with the gas outlet of the gas-liquid separator; the carbon dioxide treatment device comprises a precooling device, a compression device, an adsorption device, a drying device, a condensing device and a purifying device which are sequentially communicated.
Further, the liquid outlet of the gas-liquid separator is communicated with the regeneration tower.
The embodiment of the invention has the following beneficial effects:
the invention reasonably couples CO2 trapping and methane preparation by hydrogenation, and uses hydrogenation reaction heat for rich liquid desorption in an integrated device, thereby greatly reducing system cost and energy consumption. And a hydrogenation reaction tower is arranged, and the flow of reactants of the two hydrogenation towers is distributed through a pressure regulating valve, so that the desorption temperature and the hydrogenation reaction temperature in the desorption and hydrogenation integrated tower can be accurately controlled, and the higher reaction rate and methane selectivity are ensured.
The integrated device for preparing methane by carbon dioxide trapping hydrogenation has the characteristics of strong adaptability and high heat exchange efficiency, and can accurately control the desorption temperature and the reaction temperature by controlling the feeding flow of the matched hydrogenation reaction tower, and maintain high desorption rate, reaction rate and CH (CH) 4 Selectivity (1); CO is carried out in an integrated device 2 The hydromethanation reaction heat is used for desorption of rich liquid, so that the energy consumption of the system is reduced; the system has high integration level and low cost, and meets the requirement of carbon dioxide resource utilization.
The rich liquid is fed from the upper part and the middle part of the regeneration tower, and partial CO is desorbed by stripping 2 Then enter a reboiler to make CO therein 2 Further desorbing. Desorption of CO 2 The lean solution (105 ℃) flows out from the bottom of the regeneration tower, part of steam is flashed out by a flash tank and is pressurized and recycled back to the desorption tower to recycle heat; the heat of the lean liquid flowing out of the flash tank is recovered by the lean-rich liquid heat exchanger, then the temperature is reduced to 60 ℃, the lean liquid is pumped to a lean liquid cooler, and the lean liquid is cooled to 40 ℃ and then enters the absorption tower. The solvent is circulated back and forth to form continuous absorption and desorption of CO 2 CO 2 The trapping rate of the catalyst is more than 90 percent.
The air source of the compression and rectification purification unit is derived from CO2 regenerated gas of the CO2 trapping device, wherein main impurities are sulfur-containing substances and other trace impurities, and the main impurities are adsorbed and removed in an adsorber through high-quality activated carbon, so that the product index is fundamentally ensured to meet the food-grade quality standard, no large amount of waste water and waste liquid are discharged in the production process, no harmful substances are contained in discharged tail gas, and the discharge requirement is completely met.
Drawings
FIG. 1 is a schematic structural diagram of an integrated reaction device for producing methane by carbon dioxide trapping hydrogenation in an embodiment of the invention;
FIG. 2 is a graph showing the absorption of solvent solutions of different formulations over time in an example of the present invention;
FIG. 3 is a graph showing the absorption rate of solvent solutions of different formulations over time in an example of the present invention;
FIG. 4 is a graph showing the desorption rate of solvent solutions of different formulations over time in an example of the present invention;
FIG. 5 is a bar graph of solution desorption rate in an embodiment of the present invention.
Detailed Description
The present application is further described below with reference to examples.
In order to more clearly describe embodiments of the present invention or technical solutions in the prior art, in the following description, different "an embodiment" or "an embodiment" does not necessarily refer to the same embodiment. Various embodiments may be substituted or combined, and other implementations may be obtained from these embodiments by those of ordinary skill in the art without undue burden.
1-5, a carbon dioxide capturing and processing integrated method for flue gas discharged by a natural gas boiler comprises the following steps:
the flue gas is desulfurized and alkali washed and then enters an absorption tower, an absorbent is adopted for absorbing to obtain rich liquid, and the absorbent adopted in the absorption tower is MEA-PEHA solution with the concentration ratio of 5:5;
the rich liquid enters a carbon dioxide subsequent collection procedure or enters a carbon dioxide trapping hydrogenation methane preparation integrated reaction procedure;
the subsequent carbon dioxide collection procedure comprises the following steps:
the rich liquid is regenerated in a regeneration tower to obtain lean liquid, and the lean liquid enters an absorption tower, and the rich liquid and the lean liquid exchange heat; the carbon dioxide gas is obtained after the gas exhausted from the regeneration tower is subjected to gas-liquid separation; the carbon dioxide gas is collected after precooling, compression, adsorption, drying, condensation and purification;
the integrated reaction procedure for preparing methane by carbon dioxide trapping hydrogenation comprises the following steps:
the rich liquid is desorbed in the desorption hydrogenation integrated tower (2) after passing through a heat exchanger, and the liquid is separated by a gas-liquid separator (5) after passing through the heat exchanger and exchanges heat with the absorbent which flows out of the absorption tower (1) and absorbs carbon dioxide, and then enters the absorption tower again for absorbing carbon dioxide;
the gas separated in the gas-liquid separator (5) is mixed with hydrogen and then enters a desorption hydrogenation integrated tower (2) and a hydrogenation reaction tower (3);
the air inlet of the hydrogenation reaction tower (3) is connected with a pressure regulating valve.
In some embodiments of the invention, a carbon dioxide trapping hydrogenation methane production integrated reaction device comprises an absorption tower 1, a desorption hydrogenation integrated tower 2 and a hydrogenation reaction tower 3;
the absorbent absorbing carbon dioxide in the absorption tower 1 is desorbed in the desorption hydrogenation integrated tower 2 after passing through a heat exchanger, and liquid separated by a gas-liquid separator 5 is subjected to heat exchange with the absorbent absorbing carbon dioxide flowing out of the absorption tower 1 after passing through the heat exchanger, and then enters the absorption tower again for absorbing carbon dioxide;
the gas separated in the gas-liquid separator 5 is mixed with hydrogen and then enters a desorption hydrogenation integrated tower 2 and a hydrogenation reaction tower 3;
the air inlet of the hydrogenation reaction tower 3 is connected with a pressure regulating valve.
In some embodiments of the present invention, a spraying device for spraying the absorption solvent is arranged in the absorption tower 1;
the liquid outlet 21 of the absorption tower 1 is connected with the cold side inlet of the heat exchanger 4 in series through a pipeline, and the cold side outlet of the heat exchanger 4 is connected with the liquid inlet 23 of the desorption hydrogenation integrated tower 2 through a pipeline;
the liquid outlet 24 of the desorption hydrogenation integrated tower 2 is connected with the gas-liquid separator 5, the liquid outlet of the gas-liquid separator is connected with the hot side inlet of the heat exchanger 4 in series through a pipeline, and the hot side outlet of the heat exchanger 4 is connected with the liquid inlet 22 of the absorption tower 1 through a pipeline;
the gas outlet of the gas-liquid separator 5 is connected with a gas mixing tank 6 through a pipeline; the gas outlet of the gas mixing tank 6 is connected with the compressor 7 through a pipeline; the compressor 7 is connected with the air inlet 25 of the desorption hydrogenation integrated tower 2 and the air inlet 27 of the hydrogenation reaction tower 3 in parallel through pipelines; the desorption hydrogenation integrated tower 2 is a shell-and-tube type, carbon dioxide and hydrogen are introduced into the tube side, a rich solution is introduced into the shell side, and the flow heat exchange mode can be countercurrent or concurrent; at least one carbon dioxide hydrogenation catalyst is filled in the heat exchange tube bundle 18 of the desorption hydrogenation integrated tower 2; the heat exchange tube bundle 18 of the desorption hydrogenation integrated tower 2 is in the form of a light tube or an inner fin tube.
In some embodiments of the present invention, the desorption hydrogenation integrated tower 2 is provided with at least one hydrogenation reaction tower 3, the inlets of the desorption hydrogenation integrated tower 2 and the hydrogenation reaction tower 3 are connected with a gas mixing tank 6 through a pipeline, and inlet reactant flows of the two towers are distributed through a pressure regulating valve.
In some embodiments of the invention, the tube side and shell side of the integrated desorption hydrogenation column 2 are equipped with thermometers 12, 13.
In some embodiments of the invention, the lean liquid desorbed by the desorption hydrogenation integrated tower 2 transfers heat to the absorption tower 1 through the heat exchanger 4 to absorb CO 2 The rich liquid is obtained.
In some embodiments of the invention, CH is arranged on the gas outlet 26 of the desorption hydrogenation integrated tower 2 4 A concentration measuring instrument.
In some embodiments of the invention, a flowmeter 9 is arranged on a pipeline connecting the gas outlet of the gas-liquid separator 5 and the gas mixing tank 6 to obtain CO 2 Flow rate to control H entering the gas mixing tank 6 2 Flow rate.
The liquid outlet 21 of the absorption tower 1 is connected with the circulating pump 16 and the cold side inlet of the heat exchanger 4 in series through pipelines; the liquid inlet 23 of the desorption hydrogenation integrated tower 2 is connected with the outlet of the cold side of the heat exchanger 4 through a pipeline; the liquid outlet 24 of the desorption hydrogenation integrated tower 2 is connected with the gas-liquid separator 5, the circulating pump 15 and the hot side inlet of the heat exchanger 4 in series through pipelines; the liquid inlet 22 of the absorption tower 1 is connected with the hot side outlet of the heat exchanger 4 through a pipeline; the gas outlet of the gas-liquid separator 5 is connected with a gas mixing tank 6 through a pipeline; the gas outlet of the gas mixing tank 6 is connected with the compressor 7 through a pipeline; the compressor 7 is connected with the air inlet 25 of the desorption hydrogenation integrated tower 2 and the air inlet 27 of the hydrogenation reaction tower 3 in parallel through pipelines.
The absorption tower 1 is provided with an air inlet 19, an air outlet 20 and a spraying device 17, and the flue gas entering from the air inlet 19 is absorbed by absorption solvent fog drops sprayed by the spraying device 17 to absorb CO2 and then leaves from the air outlet 20.
The gas outlet of the gas-liquid separator 5 is connected with a gas mixing tank 6 through a flow meter 9 to obtain CO 2 Flow rate to control H entering the gas mixing tank 6 2 Flow rate.
And a flowmeter 10 and a flowmeter 11 are arranged on connecting pipelines of the compressor 7 and the desorption hydrogenation integrated tower 2 and the hydrogenation reaction tower 3 so as to obtain the flow of the branch reactant.
The connecting pipeline of the compressor 7 and the hydrogenation reaction tower 3 is provided withPressure regulating valve 11。
A thermometer 12 is arranged in a heat exchange tube bundle 18 of the desorption hydrogenation integrated tower 2 so as to obtain the hydrogenation reaction temperature.
The shell side of the desorption hydrogenation integrated tower 2 is provided with a thermometer 13 to obtain the desorption reaction temperature.
CH is arranged on an air outlet 26 of the desorption hydrogenation integrated tower 2 4 A concentration measuring instrument.
The liquid inlet 29 of the hydrogenation reaction tower 3 is filled with a cooling medium, and the cooling medium leaves from the liquid outlet 30 after heat exchange.
The lower part of the receiving tower is provided with an air inlet and a liquid outlet, and the upper part of the receiving tower is provided with an air outlet, a liquid inlet and a spraying device; the upper part of the desorption hydrogenation integrated tower is provided with an air inlet and a liquid outlet, the upper part of the desorption hydrogenation integrated tower is provided with an air outlet and a liquid inlet, and a heat exchange tube bundle and a shell plate are arranged in the desorption hydrogenation integrated tower; the upper part of the hydrogenation reaction tower is provided with an air inlet and a liquid outlet, the upper part of the hydrogenation reaction tower is provided with an air outlet and a liquid inlet, and a heat exchange tube bundle and a shell plate are arranged in the hydrogenation reaction tower; the liquid inlet of the absorption tower is connected with the lean liquid inlet of the heat exchanger through a pipeline, and the liquid outlet of the absorption tower is connected with the rich liquid inlet of the heat exchanger through a pipeline and a circulating pump; the desorption hydrogenation integrated tower and the tube bundles of the hydrogenation reaction tower are filled with a carbon dioxide hydrogenation catalyst; the desorption hydrogenation integrated tower shell side liquid inlet is connected with the rich liquid outlet of the heat exchanger through a pipeline, and the shell side liquid outlet is connected with the lean liquid inlet of the heat exchanger through a pipeline, a gas-liquid separator and a circulating pump.
According to the embodiment of the invention, the positions of the measuring points of the temperature detector are arranged in the tube bundles and at the shell side of the desorption hydrogenation integrated tower and the hydrogenation reaction tower.
According to the embodiment of the invention, gas concentration detectors are arranged at the gas outlets of the desorption hydrogenation integrated tower and the hydrogenation reaction tower.
According to the embodiment of the invention, the gas outlet of the absorption tower and the gas-liquid separator is provided with CO 2 A concentration detector.
According to the embodiment of the invention, the tube bundles of the desorption hydrogenation integrated tower and the hydrogenation reaction tower use the inner finned tubes, so that the heat exchange coefficient of the tube side is improved.
According to the embodiment of the invention, the rich liquid at the outlet of the absorption tower is used for recovering the heat of the lean liquid at the outlet of the desorption hydrogenation integrated tower through the heat exchanger.
According to the embodiment of the invention, the desorption hydrogenation integrated tower and the hydrogenation reaction tower air inlet are connected with a gas mixing tank through a compressor and a pipeline.
According to the embodiment of the invention, the reactant flows of the air inlets of the desorption hydrogenation integrated tower and the hydrogenation reaction tower are controlled by the pressure regulating valve.
According to the embodiment of the invention, the gas outlet of the gas-liquid separator is connected with the inlet of the gas mixing tank through a pipeline and is mixed with hydrogen in proportion.
According to the embodiment of the invention, the air inlet of the absorption tower is connected with the flue, and carbon dioxide in the flue gas is recovered.
The carbon dioxide concentration in the flue gas is low, carbon dioxide is absorbed by the absorbent, and meanwhile, high-concentration carbon dioxide and hydrogen are mixed to prepare methane.
The reaction process of preparing methane by hydrogenating carbon dioxide releases heat, but the heat is used for capturing carbon dioxide in the flue gas, so that the whole energy consumption of the system can be reduced, and the methane preparation cost can be reduced.
Green methane can be produced by matching with a new energy source of hydrogen for electrolyzing water.
The technology can realize the integrated production of carbon dioxide trapping and methane preparation by hydrogenation, and reduce the energy consumption and the cost of the system.
The reaction temperature of the organic amine absorption is 40 ℃, the exothermic reaction is carried out, and the desorption temperature is 102-103.5 ℃ and the endothermic reaction is carried out. MEA 80-100 KJ/mol
The reaction temperature for preparing methane by carbon dioxide hydrogenation is 300 ℃, and the reaction heat is-165 kJ/mol.
In some embodiments of the invention, the method is completed by adopting a carbon dioxide trapping and absorbing device suitable for the flue gas discharged by a natural gas boiler, wherein the carbon dioxide trapping and absorbing device suitable for the flue gas discharged by the natural gas boiler comprises a desulfurizing device, an alkaline washing tower, an absorbing tower 1 and a regenerating tower 32 which are communicated in sequence; the front end of the desulfurizing device is communicated with the flue;
the rich liquid outlet of the absorption tower 1 is communicated with the liquid inlet of the regeneration tower 32 through a first pipeline; the liquid outlet of the regeneration tower 32 is communicated with the lean liquid inlet of the absorption tower 1 through a second pipeline; the first pipeline exchanges heat with the second pipeline through a lean rich liquid heat exchanger 34; the air outlet of the regeneration tower 32 is communicated with a gas-liquid separator 33.
In some embodiments of the present invention, the absorption tower 1 is provided with a gas outlet, and the gas outlet is communicated with the flue.
In some embodiments of the invention, a lean liquid cooler is arranged on the second pipeline.
In some embodiments of the present invention, a solution reboiler 35 is further included, and the solution reboiler 35 is in communication with the regeneration tower 32 via a circulation line.
In some embodiments of the present invention, the apparatus further comprises a carbon dioxide treatment device, and the carbon dioxide treatment device is communicated with the air outlet of the gas-liquid separator 33.
In some embodiments of the present invention, the carbon dioxide treatment device includes a pre-cooling device, a compression device, an adsorption device, a drying device, a condensing device, and a purifying device, which are sequentially connected.
In some embodiments of the present invention, the liquid outlet of the gas-liquid separator 33 is in communication with the regeneration tower 32.
In order to improve the absorption effect, the applicant independently develops a carbon dioxide trapping absorbent suitable for the flue gas discharged by the natural gas boiler, and designs a carbon dioxide trapping process flow of the gas boiler on the basis.
The applicant has carried out a number of studies to obtain the effect of the absorbent: the optimal concentration ratio of the MEA-DETA solution is 5:5, the optimal concentration ratio of the MEA-TETA compound solution is 6:4, the optimal concentration ratio of the MEA-TEPA compound solution is 6:4, and the optimal concentration ratio of the MEA-PEHA compound solution is 5:5. Comparing the absorption and desorption properties of the four compound solutions to obtain the optimal solvent formula.
Solution CO of four formula solvent solutions in absorption experiment 2 The absorption capacity versus time is shown in figure 2.
Analysis of each curve can show that the absorption rate of the MEA-PEHA solution is significantly higher than the other three curves, and the absorption rate of the MEA-DETA solution is the lowest. The carbon dioxide absorption capacity of the four solutions is sequentially MEA-PEHA solution > MEA-TEPA solution > MEA-TETA solution > MEA-DETA solution.
Solution absorption of CO in absorption experiments with four formulation solvent solutions 2 The absorption rate versus time is shown in figure 3.
From the graph, the absorption rate change curve of the MEA-PEHA solution is obviously higher than that of other curves, and the change rule is consistent with the change rule of the absorption amount with time.
CO is desorbed from the four formula solvent solution rich solutions in desorption experiments 2 The desorption rate of (c) is plotted against time in fig. 4.
As described above, the time-dependent curves of the desorption rates of the four formulation solvents show high coincidence, and the change rule is that the desorption rates of the four formulation solvents are rapidly increased and then gradually decreased at the initial stage of the test, and the desorption rates of the four formulation solvents are basically consistent.
The comparison of the desorption rates of the four formulation solvents is shown in figure 5. The data in the analytical graph shows that the MEA-DETA solution has the highest desorption rate and the MEA-PEHA solution has the lowest desorption rate.
The results of the four formulation solvent desorption experiments are shown in Table 1. As can be seen from the table, the MEA-PEHA solution has a minimum desorption temperature of 68℃and a minimum constant boiling temperature of 102 ℃.
TABLE 1 Desorption experiment results for different absorbent solutions
According to the test results, the absorption effect, the desorption effect and the desorption energy consumption of each solution are combined, and when the concentration ratio of the MEA-PEHA compound solution is 5:5, the test effect is optimal. Therefore, the optimal binary compound solvent under the test conditions is MEA-PEHA solution with the concentration ratio of 5:5.
Sulfur and nitrate resistance analysis of composite solutions
SO in flue gas 2 Research on influence on trapping performance
Test conditions: feed gas SO 2 ～1000ppm，CO 2 About 12 percent of raw material gas about 3.5Nm 3 /h。
TABLE 2 Desorption experiment results for different absorbent solutions
Complex amine solution vs SO 2 The absorptivity of (c) is close to 100%. As the total sulfur content in the solution increases, CO 2 The absorption rate decreases. SO in regenerated gas 2 The content was always less than 1ppm, indicating SO 2 It is difficult to regenerate under the test conditions.
NO in flue gas x Research on influence on trapping performance
Test conditions: feed gas CO 2 About 12 percent of raw material gas about 3.5Nm 3 /h。
TABLE 3 Desorption experiment results for different absorbent solutions
To verify NO x The influence of accumulation in the solvent on carbon absorption is carried out to carry out a high-concentration nitrogen oxide enhanced absorption test to study the influence on CO 2 Influence of absorption properties.
TABLE 4 Desorption experiment results for different absorbent solutions
By CO 2 The trapped pilot experiment study can lead to the following conclusions:
whether the single-component absorbent solution or the binary compound absorbent solution, the absorption capacity can be rapidly increased at the initial stage of the experiment, then the increase amplitude is gradually reduced, and the absorption rate and the desorption rate both show a change rule of increasing first and then decreasing.
The best concentration ratio of each group of binary compound absorbent solution can be obtained by combining the results of absorption and desorption experiments: the optimal concentration ratio of the MEA-DETA solution is 5:5, the optimal concentration ratio of the MEA-TETA compound solution is 6:4, the optimal concentration ratio of the MEA-TEPA compound solution is 6:4, and the optimal concentration ratio of the MEA-PEHA compound solution is 5:5.
From the experimental effect only, comparing the four binary compound absorbent solutions results in an MEA-PEHA solution with an optimal formulation of 5:5 concentration ratio.
The main reason why the organic amine method causes serious equipment corrosion is that the organic amine and CO 2 The carbamate and the chemical degradation products of the organic amine produced by the reaction. A great deal of research is carried out at home and abroad, and although a certain progress is made in the aspect of preservative development, the problem of reducing equipment corrosion caused by reducing organic amine degradation is not thoroughly solved. Through a great deal of experimental study, firstly, antioxidant and active amine are added to solve the chemical degradation of organic amine, and the organic amine is absorbed in the prior artOn the basis of the system, a group of preservatives are developed and added into the compound amine solution, so that the corrosion rate of the solution to equipment is less than 0.076mm/a, and the technical problem of serious equipment corrosion caused by an organic amine method is fundamentally solved.
Summary of the process
Flue gas (65 ℃ and normal pressure) from the outlet of the desulfurization absorption tower 1 is subjected to alkaline washing pretreatment and then cooled to 40 ℃, and enters a capturing and purifying device for decarburization treatment. Absorbing CO in flue gas by adopting organic amine composite absorbent 2 The flue gas enters the absorption tower 1 from the bottom of the tower and is reversely contacted with the absorption liquid, and the interstage cooling technology is utilized to reduce the reaction heat, improve the absorption efficiency and absorb CO 2 The rich liquid is pumped from the bottom of the tower to a lean rich liquid heat exchanger 34, and the heat is recovered and then sent to a regeneration tower 32. De-aspirating CO 2 Separating with water vapor to remove water to obtain product CO with purity of 99.5% (dry basis) or more 2 And (5) entering a subsequent compression process. Condensed water condensed and separated from the regenerated gas is returned to the underground tank, and the regenerated tower 32 is periodically replenished with liquid by a replenishing pump.
The rich liquid is fed from the upper and middle streams of the regeneration tower 32, and a part of CO is desorbed by stripping 2 Then enters a reboiler 35 to make CO therein 2 Further desorbing. Desorption of CO 2 The lean solution (105 ℃) flows out from the bottom of the regeneration tower 32, and part of steam is flashed out by a flash tank to be pressurized and recovered to the desorption tower to recover heat; the heat of the lean liquid flowing out of the flash tank is recovered by the lean-rich liquid heat exchanger 34, then the temperature is reduced to 60 ℃, the lean liquid is pumped to a lean liquid cooler, and the lean liquid is cooled to 40 ℃ and then enters the absorption tower 1. The solvent is circulated back and forth to form continuous absorption and desorption of CO 2 CO 2 The trapping rate of the catalyst is more than 90 percent.
The regeneration energy consumption of 30wt% composite amine absorbent is less than or equal to 3.0GJ/t CO 2 The cyclic absorption load is more than or equal to 23LCO 2 solution/L.
The air source of the compression and rectification purification unit is derived from CO 2 Trapping device CO 2 The regenerated gas contains sulfur and other trace impurities as main impurities, and is adsorbed and removed in an adsorber through high-quality active carbon, so that the product index is fundamentally ensured to meet the food-grade quality standard,in the production process, a large amount of wastewater and waste liquid are not discharged, and the discharged tail gas basically contains no harmful substances, so that the discharge requirement is completely met.
The project adopts the combined technology of precooling, adsorption, drying and low-temperature rectification.
(1) Precooling: the precooler is used for reducing the temperature of the carbon dioxide to ensure that the outlet temperature is about 15 ℃.
(2) Compression: the device adopts a medium pressure method to produce liquid carbon dioxide, and according to the thermodynamic condition of a carbon dioxide phase diagram, pure carbon dioxide can obtain liquid carbon dioxide as long as the condition of a carbon dioxide liquefying region with the pressure of 2.1MPa and the temperature of minus 20 ℃ can be kept. Because the purity of the raw material gas carbon dioxide entering the device is more than 99% (dry basis), and the rest is non-condensable gas, in order to reduce the carbon dioxide loss in the purification process, the final pressure of the raw material gas carbon dioxide is required to be increased to 2.5MPa through three-stage compression without oil lubrication, R22 is used for evaporation at the temperature of minus 28 ℃ to minus 31 ℃, and the compressed carbon dioxide gas is indirectly cooled to minus 25 ℃ to be liquefied.
(3) Adsorption: the adsorber is filled with active carbon to adsorb sulfur-containing impurities contained in the raw material gas and possibly oil-containing impurities brought by the compressor.
(4) And (3) drying: the molecular sieve is filled in the dryer, mainly for satisfying the following conditions: (1) the quality index that the water content of the liquid carbon dioxide product is less than or equal to 20ppm is satisfied; (2) in order to ensure that the saturated moisture in the carbon dioxide gas source is frozen at low temperature to block the pipeline and equipment in the process of liquefying and purifying the carbon dioxide, so that the production cannot be continued; and (3) removing trace water in the gas by utilizing the adsorption of the molecular sieve adsorbent to water, so as to ensure that the moisture of the carbon dioxide raw material gas after precooling and drying is less than or equal to 20ppm. And (3) heating and regenerating the molecular sieve after adsorption saturation, and recycling the molecular sieve. The drying tower adopts a one-open one-standby mode.
(5) Condensing and liquefying: the discharged gas containing 99% of carbon dioxide is subjected to the purification procedures of compression, precooling, adsorption, drying and the like, and then enters a condenser for condensation and liquefaction. Evaporating the liquid R22 at-25 to-30 ℃, and indirectly cooling the compressed carbon dioxide gas to condense and liquefy the carbon dioxide gas into liquid carbon dioxide.
(6) Purifying: the liquefied liquid carbon dioxide is purified, a composite rectification purification tower is adopted, and impurities are separated under specific conditions by utilizing a low-temperature rectification principle according to the difference of boiling points of the carbon dioxide and impurity components, so that the purity of the carbon dioxide is improved, a qualified liquid carbon dioxide product is obtained, and the gas consumption of the product is reduced.
(7) Auxiliary facilities:
r507 condensing system: the process device adopts a medium pressure method to produce liquid carbon dioxide. And cooling and liquefying carbon dioxide gas, and cooling discharged air at the top of the purification tower through a refrigerating unit. R507 is taken as a refrigerant, cold energy is transferred to carbon dioxide to liquefy the carbon dioxide through low-temperature evaporation of the R507, then the gaseous R507 is compressed by an ice machine and condensed by an evaporation condenser, the gaseous R507 is condensed into liquid R507, and then the liquid R507 is evaporated by the condenser to absorb heat, thus completing the refrigeration cycle.
It should be noted that the above embodiments can be freely combined as needed. The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The integrated method for capturing and processing carbon dioxide in the flue gas discharged by the natural gas boiler is characterized by comprising the following steps of:
the flue gas is desulfurized and alkali washed and then enters an absorption tower, an absorbent is adopted for absorbing to obtain rich liquid, and the absorbent adopted in the absorption tower is MEA-PEHA solution with the concentration ratio of 5:5;
the rich liquid enters a carbon dioxide subsequent collection procedure or enters a carbon dioxide trapping hydrogenation methane preparation integrated reaction procedure;
the subsequent carbon dioxide collection procedure comprises the following steps:
the rich liquid is regenerated in a regeneration tower to obtain lean liquid, and the lean liquid enters an absorption tower, and the rich liquid and the lean liquid exchange heat; the carbon dioxide gas is obtained after the gas exhausted from the regeneration tower is subjected to gas-liquid separation; the carbon dioxide gas is collected after precooling, compression, adsorption, drying, condensation and purification;
the integrated reaction procedure for preparing methane by carbon dioxide trapping hydrogenation comprises the following steps:
the rich liquid is desorbed in the desorption hydrogenation integrated tower (2) after passing through a heat exchanger, and the liquid is separated by a gas-liquid separator (5) after passing through the heat exchanger and exchanges heat with the absorbent which flows out of the absorption tower (1) and absorbs carbon dioxide, and then enters the absorption tower again for absorbing carbon dioxide;
the gas separated in the gas-liquid separator (5) is mixed with hydrogen and then enters a desorption hydrogenation integrated tower (2) and a hydrogenation reaction tower (3);
the air inlet of the hydrogenation reaction tower (3) is connected with a pressure regulating valve.
2. The integrated method for carbon dioxide trapping and processing of flue gas discharged by a natural gas boiler according to claim 1, wherein the integrated reaction procedure for preparing methane by carbon dioxide trapping and hydrogenation is completed by adopting an integrated reaction device for preparing methane by carbon dioxide trapping and hydrogenation, and the integrated reaction device for preparing methane by carbon dioxide trapping and hydrogenation comprises an absorption tower (1), a desorption and hydrogenation integrated tower (2) and a hydrogenation reaction tower (3);
the carbon dioxide-absorbed absorbent in the absorption tower (1) is desorbed in the desorption hydrogenation integrated tower (2) through a heat exchanger, and liquid separated by a gas-liquid separator (5) is subjected to heat exchange with the carbon dioxide-absorbed absorbent flowing out of the absorption tower (1) through the heat exchanger and then enters the absorption tower again for carbon dioxide absorption;
the gas separated in the gas-liquid separator (5) is mixed with hydrogen and then enters a desorption hydrogenation integrated tower (2) and a hydrogenation reaction tower (3);
the air inlet of the hydrogenation reaction tower (3) is connected with a pressure regulating valve.
3. The integrated method for capturing and processing carbon dioxide in flue gas discharged by a natural gas boiler according to claim 2, wherein a spraying device for spraying an absorption solvent is arranged in the absorption tower (1);
the liquid outlet (21) of the absorption tower (1) is connected with the cold side inlet of the heat exchanger (4) in series through a pipeline, and the cold side outlet of the heat exchanger (4) is connected with the liquid inlet (23) of the desorption hydrogenation integrated tower (2) through a pipeline;
the liquid outlet (24) of the desorption hydrogenation integrated tower (2) is connected with a gas-liquid separator (5), the liquid outlet of the gas-liquid separator is connected with the hot side inlet of the heat exchanger (4) in series through a pipeline, and the hot side outlet of the heat exchanger (4) is connected with the liquid inlet (22) of the absorption tower (1) through a pipeline;
the gas outlet of the gas-liquid separator (5) is connected with the gas mixing tank (6) through a pipeline; the air outlet of the air mixing tank (6) is connected with the compressor (7) through a pipeline; the compressor (7) is connected with an air inlet (25) of the desorption hydrogenation integrated tower (2) and an air inlet (27) of the hydrogenation reaction tower (3) in parallel through pipelines; the desorption hydrogenation integrated tower (2) is a shell-and-tube type, carbon dioxide and hydrogen are introduced into the tube side, a rich solution is introduced into the shell side, and the flow heat exchange mode can be countercurrent or concurrent; at least one carbon dioxide hydrogenation catalyst is filled in a heat exchange tube bundle (18) of the desorption hydrogenation integrated tower (2); the heat exchange tube bundle (18) of the desorption hydrogenation integrated tower (2) is in the form of a light tube or an inner fin tube.
4. The integrated method for capturing and processing carbon dioxide in flue gas discharged from a natural gas boiler according to claim 3, wherein the desorption hydrogenation integrated tower (2) is provided with at least one hydrogenation reaction tower (3), the inlets of the desorption hydrogenation integrated tower (2) and the hydrogenation reaction tower (3) are connected with a gas mixing tank (6) through a pipeline, and the inlet reactant flow of the two towers is distributed through a pressure regulating valve.
5. The integrated reaction device for methane production by carbon dioxide trapping hydrogenation according to claim 4, wherein the pipe side and the shell side of the integrated desorption hydrogenation tower (2) are provided with thermometers (12, 13).
6. The natural gas boiler exhaust fumes of claim 5The integrated method for capturing and processing carbon dioxide is characterized in that lean liquid desorbed by the desorption hydrogenation integrated tower (2) transfers heat to the absorption tower (1) to absorb CO through the heat exchanger (4) 2 The rich liquid is obtained.
7. The integrated method for capturing and processing carbon dioxide in flue gas discharged from a natural gas boiler according to claim 6, wherein a gas outlet (26) of the desorption hydrogenation integrated tower (2) is provided with CH 4 A concentration measuring instrument. The gas outlet of the gas-liquid separator 5 is connected with a gas mixing tank 6 through a flow meter 9 to obtain CO 2 Flow rate to control H entering the gas mixing tank 6 2 Flow rate.
8. The integrated method for capturing and processing carbon dioxide in flue gas discharged by a natural gas boiler according to claim 1, wherein the subsequent collection procedure of carbon dioxide is completed by adopting a carbon dioxide capturing and absorbing device suitable for the flue gas discharged by the natural gas boiler, and the carbon dioxide capturing and absorbing device suitable for the flue gas discharged by the natural gas boiler comprises a desulfurizing device, an alkaline washing tower, an absorbing tower and a regenerating tower which are communicated in sequence; the front end of the desulfurizing device is communicated with the flue;
the rich liquid outlet of the absorption tower is communicated with the liquid inlet of the regeneration tower through a first pipeline; the liquid outlet of the regeneration tower is communicated with the lean liquid inlet of the absorption tower through a second pipeline; the first pipeline and the second pipeline exchange heat through a lean-rich liquid heat exchanger; the air outlet of the regeneration tower is communicated with the gas-liquid separator.
9. The integrated method for capturing and processing carbon dioxide in flue gas discharged from a natural gas boiler according to claim 8, wherein a gas outlet is arranged on the absorption tower and is communicated with the flue; the second pipeline is provided with a lean solution cooler; the subsequent carbon dioxide collecting procedure adopts a carbon dioxide capturing and absorbing device suitable for the flue gas discharged by a natural gas boiler and further comprises a solution reboiler, wherein the solution reboiler is communicated with a regeneration tower through a circulating pipeline; the subsequent collection procedure of the carbon dioxide adopts a carbon dioxide capturing and absorbing device suitable for the flue gas discharged by a natural gas boiler and further comprises a carbon dioxide treatment device, and the carbon dioxide treatment device is communicated with the gas outlet of the gas-liquid separator; the carbon dioxide treatment device comprises a precooling device, a compression device, an adsorption device, a drying device, a condensing device and a purifying device which are sequentially communicated.
10. The carbon dioxide capturing and absorbing device suitable for flue gas discharged by a natural gas boiler according to claim 2, wherein the liquid outlet of the gas-liquid separator is communicated with the regeneration tower.
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