CN117448842A - Method and device for producing hydrogen by carbon trapping coupling - Google Patents
Method and device for producing hydrogen by carbon trapping coupling Download PDFInfo
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- CN117448842A CN117448842A CN202210841877.8A CN202210841877A CN117448842A CN 117448842 A CN117448842 A CN 117448842A CN 202210841877 A CN202210841877 A CN 202210841877A CN 117448842 A CN117448842 A CN 117448842A
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- 239000001257 hydrogen Substances 0.000 title claims abstract description 39
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 39
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 37
- 238000000034 method Methods 0.000 title claims abstract description 30
- 230000008878 coupling Effects 0.000 title claims abstract description 17
- 238000010168 coupling process Methods 0.000 title claims abstract description 17
- 238000005859 coupling reaction Methods 0.000 title claims abstract description 17
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 15
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 15
- 239000007788 liquid Substances 0.000 claims abstract description 233
- 238000010521 absorption reaction Methods 0.000 claims abstract description 212
- 238000005868 electrolysis reaction Methods 0.000 claims abstract description 60
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims abstract description 52
- 239000012528 membrane Substances 0.000 claims abstract description 48
- 238000004519 manufacturing process Methods 0.000 claims abstract description 20
- KWYUFKZDYYNOTN-UHFFFAOYSA-M potassium hydroxide Substances [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 67
- 229910052783 alkali metal Inorganic materials 0.000 claims description 34
- 229910000288 alkali metal carbonate Inorganic materials 0.000 claims description 28
- 150000008041 alkali metal carbonates Chemical class 0.000 claims description 27
- -1 alkali metal bicarbonate Chemical class 0.000 claims description 22
- 239000007789 gas Substances 0.000 claims description 22
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 21
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 claims description 13
- 239000002994 raw material Substances 0.000 claims description 12
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical group [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 11
- 229920005597 polymer membrane Polymers 0.000 claims description 10
- 239000002912 waste gas Substances 0.000 claims description 8
- 239000004695 Polyether sulfone Substances 0.000 claims description 6
- 239000004734 Polyphenylene sulfide Substances 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 6
- 229920002492 poly(sulfone) Polymers 0.000 claims description 6
- 229920006393 polyether sulfone Polymers 0.000 claims description 6
- 229920000069 polyphenylene sulfide Polymers 0.000 claims description 6
- 239000011347 resin Substances 0.000 claims description 4
- 229920005989 resin Polymers 0.000 claims description 4
- 229920000642 polymer Polymers 0.000 claims description 3
- 230000008929 regeneration Effects 0.000 abstract description 20
- 238000011069 regeneration method Methods 0.000 abstract description 20
- 230000002829 reductive effect Effects 0.000 abstract description 6
- 229910001854 alkali hydroxide Inorganic materials 0.000 abstract description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 36
- 239000000243 solution Substances 0.000 description 29
- 239000001569 carbon dioxide Substances 0.000 description 18
- 229910002092 carbon dioxide Inorganic materials 0.000 description 18
- 239000003513 alkali Substances 0.000 description 17
- 239000011259 mixed solution Substances 0.000 description 17
- 239000003792 electrolyte Substances 0.000 description 14
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 14
- 150000001340 alkali metals Chemical class 0.000 description 13
- 238000006243 chemical reaction Methods 0.000 description 12
- 239000000047 product Substances 0.000 description 10
- 238000005516 engineering process Methods 0.000 description 9
- 238000009792 diffusion process Methods 0.000 description 8
- 239000012670 alkaline solution Substances 0.000 description 7
- 229910000027 potassium carbonate Inorganic materials 0.000 description 7
- 235000011181 potassium carbonates Nutrition 0.000 description 7
- 239000003463 adsorbent Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 239000002250 absorbent Substances 0.000 description 5
- 230000002745 absorbent Effects 0.000 description 5
- 150000001412 amines Chemical class 0.000 description 5
- 238000005265 energy consumption Methods 0.000 description 5
- 150000002500 ions Chemical class 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 4
- 239000003546 flue gas Substances 0.000 description 4
- 239000003014 ion exchange membrane Substances 0.000 description 4
- 238000004064 recycling Methods 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 238000004146 energy storage Methods 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000006096 absorbing agent Substances 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 2
- 239000000920 calcium hydroxide Substances 0.000 description 2
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 239000011736 potassium bicarbonate Substances 0.000 description 2
- 235000015497 potassium bicarbonate Nutrition 0.000 description 2
- 229910000028 potassium bicarbonate Inorganic materials 0.000 description 2
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 description 2
- 230000001172 regenerating effect Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 239000002918 waste heat Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
- AFCARXCZXQIEQB-UHFFFAOYSA-N N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CCNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 AFCARXCZXQIEQB-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910001413 alkali metal ion Inorganic materials 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 150000007942 carboxylates Chemical class 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000001010 compromised effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000029087 digestion Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000005431 greenhouse gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 231100000086 high toxicity Toxicity 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000012492 regenerant Substances 0.000 description 1
- 230000009919 sequestration Effects 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 238000001926 trapping method Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/02—Hydrogen or oxygen
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/14—Alkali metal compounds
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/14—Alkali metal compounds
- C25B1/16—Hydroxides
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
- C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
- C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention provides a method and a device for producing hydrogen by carbon capture coupling. The method comprises the following steps: capturing low concentration CO with alkali hydroxide solution 2 Obtaining low concentration CO 2 Absorption liquid utilizing first part of low concentration CO 2 The absorption liquid captures high-concentration CO 2 Obtaining high concentration CO 2 An absorption liquid; the second part of low concentration CO 2 The absorption liquid is used as cathode liquid, and high concentration CO 2 The absorption liquid is used as an anode liquid, and the nonionic diaphragm is used as a diaphragm to carry out electrolysis. The method of the invention can realize the wide concentration range of CO 2 Is not used for trappingThe ionic membrane is electrolyzed to realize the regeneration of the absorption liquid and the coupling hydrogen production, so that the CO with a wide concentration range can be reduced 2 Trapping costs and obtaining H 2 、O 2 And simultaneously reduces the hydrogen production cost.
Description
Technical Field
The invention relates to the technical field of carbon capture, in particular to a method and a device for producing hydrogen by carbon capture coupling.
Background
Global warming is currently one of the major environmental problems in the world, carbon dioxide being the major greenhouse gas. The existing carbon capture, utilization and sequestration technology (CCUS), particularly the air capture technology (Direct Air Capture), and the electrolytic water hydrogen production cost are too high to popularize, and the storage, transportation and digestion technologies are not mature, so that the development of the technology is severely limited. At present, the carbon dioxide trapping method is mainly a liquid amine solvent adsorption method, and the existing liquid amine solvent has the defects of high regeneration energy consumption, strong corrosiveness, high toxicity, easy volatilization and high cost, and is a main obstacle for restricting the development of the trapping technology at present. The method can only collect carbon dioxide with higher enrichment degree such as flue gas, and cannot be applied to collecting carbon dioxide with low enrichment degree such as air. In recent years, the technology for capturing carbon dioxide in air is developed, and carbon dioxide is adsorbed by adopting a liquid alkaline solution and a solid amine film, so that CO in a wide enrichment range can be realized 2 Is included in the collection of the liquid.
However, the above-described technology for capturing carbon dioxide in air has a problem that the energy consumption for regenerating the carbon dioxide adsorbent is high. When solid amine film is used as adsorbent to trap carbon dioxide in air, the cost of amine adsorbent is high, and the economic cost in commercial utilization is high. The other technical route adopts liquid alkali solution as absorption liquid, and adopts a two-step chemical reaction to regenerate the adsorbent, namely, the first step realizes that carbon dioxide and alkali solution are combined to form carbonate solution, and simultaneously regenerates the absorption liquid, then calcium hydroxide reacts with the carbonate solution obtained in the first step to form calcium carbonate precipitate, and then high-purity carbon dioxide is formed after calcination, and the regeneration of calcium hydroxide is realized. The technical route has the advantages of high energy consumption, large equipment investment and poor economical efficiency.
The patent WO2011123817A3 and the patent CN102605383A use alkaline ion exchange membranes for carbon capture, have harsh use conditions, high membrane cost and no commercial utilization value; patent AU2009290161B2 uses an alkaline ion exchange membrane and its carbon dioxide enters the electrolyzer in gaseous form and combines with the lye in the electrolyzer via a gas diffusion layer to form NaOH-NaHCO 3 -Na 2 CO 3 The mixed solution cannot form high-purity alkaline solution for regeneration, and the concentration of the carbon dioxide to be supplemented is high, so that the carbon dioxide in the air cannot be utilized for electrolysis after being trapped; patent US9095813b2 adopts an alkaline solution adsorption technology, gas adsorbent reduction is realized through two chemical loops, the system design is complex, the manufacturing cost is high, the control system is difficult to realize, the regeneration chemical loop needs 900 ℃ combustion heating, the energy loss and carbon emission are greatly increased, the calcium oxide adsorbent is easy to deactivate, and a large amount of calcium carbonate is needed to be supplemented; air capture CO of patent US20170113184A1 and patent EP2160234A1 2 The device is also a solid membrane capturing technology, needs steam for absorbent reduction, and also increases CO 2 Emission can only solve the problem of CO 2 The problem of capturing cannot solve CO 2 The utilization problem.
Also in the prior art, potassium hydroxide is used for absorbing CO 2 Obtaining potassium carbonate; then electrolyzing potassium carbonate by an ion membrane, wherein the potassium carbonate generates potassium bicarbonate, potassium carbonate mixed solution and O at the anode 2 And CO 2 Gas, cathode to obtain H 2 And KOH solution to realize the regeneration scheme of absorption liquid. However, in order to prevent the reaction of anode potassium bicarbonate and cathode potassium hydroxide in the electrolysis process, an ion exchange membrane is mostly adopted to separate the cathode liquid chamber and the anode liquid chamber, and the ion membrane is expensive and mainly has harsh use conditions, so that the cost is high, and the application range is limited by the complicated purification processAnd (5) enclosing. Secondly, KOH absorbs low concentration CO 2 For example CO in air 2 In general, only KOH-K is obtained 2 CO 3 Mixed solution, it is difficult to obtain K completely converted 2 CO 3 This results in too low a KOH utilization. If KOH is to be completely converted into potassium carbonate, the air passage is increased, but the post-CO 2 Absorption Rate and CO 2 The utilization efficiency is too low. Thirdly, if a mixed solution of potassium carbonate containing a certain amount of potassium hydroxide is introduced into the anolyte, the efficiency of the anodically acidifying potassium carbonate is compromised.
Disclosure of Invention
The invention mainly aims to provide a method and a device for preparing hydrogen by carbon trapping coupling, which aim to solve the problem of wide concentration of CO in the prior art 2 The trapping cost and the hydrogen production cost are both high.
In order to achieve the above object, according to one aspect of the present invention, there is provided a method for producing hydrogen by carbon capture coupling, comprising the steps of: step S1, capturing low concentration CO with alkali metal hydroxide solution 2 Obtaining low concentration CO 2 Absorption liquid, low concentration CO 2 The absorption liquid contains alkali metal carbonate and alkali metal hydroxide; step S2, low concentration CO 2 The absorption liquid is divided into a first part of low-concentration CO 2 Absorption liquid and second part of low concentration CO 2 Absorption liquid utilizing first part of low concentration CO 2 The absorption liquid captures high-concentration CO 2 Obtaining high concentration CO 2 Absorption liquid, high concentration CO 2 The absorption liquid contains alkali carbonate and alkali bicarbonate; step S3, the second part of low concentration CO 2 The absorption liquid is used as cathode liquid, and high concentration CO 2 The absorption liquid is used as anode liquid, the nonionic diaphragm is used as diaphragm for electrolysis, and H is obtained at the electrolysis cathode 2 And cathode liquid is discharged, O is obtained at the electrolysis anode 2 、CO 2 And anode liquid is discharged, the cathode liquid is returned to the step S1, the cathode liquid contains alkali metal carbonate and alkali metal hydroxide, and the anode liquid contains alkali metal carbonate and alkali metal bicarbonate.
Further, the alkali metal hydroxide is KOH, alkali metalThe carbonate is K 2 CO 3 The alkali metal bicarbonate is KHCO 3 The method comprises the steps of carrying out a first treatment on the surface of the Or the alkali metal hydroxide is NaOH, and the alkali metal carbonate is Na 2 CO 3 The alkali metal bicarbonate is NaHCO 3 。
Further, in step S2, the first portion of low concentration CO in volume percent 2 The absorption liquid is low-concentration CO 2 10-90% of absorption liquid.
Further, step S3 further includes: taking the anode liquid as anode liquid to electrolyze; preferably, the concentration of carbonate in the catholyte is 0.1-6M, and the concentration of hydroxide is 0.1-10M; more preferably, the concentration of carbonate in the catholyte is 0.5-3M and the concentration of hydroxide is 3-7M; preferably, the concentration of carbonate in the anolyte is 0.1-6.5M, and the concentration of bicarbonate is 0.1-3M; more preferably, the concentration of carbonate in the anolyte is 2 to 5M and the concentration of bicarbonate is 0.6 to 1.5M.
Further, the nonionic membrane is one or more of a porous polymer membrane, a Zirfon membrane, a polyphenylene sulfide membrane, a polysulfone membrane and a polyethersulfone membrane; preferably, the non-ionic membrane is a porous polymer membrane; more preferably, the surface polymer layer of the porous polymer membrane is one or more of a carboxylate ion resin layer, polyphenylene sulfide, polysulfone, and polyethersulfone.
According to another aspect of the present invention, there is provided a carbon-trap coupled hydrogen production apparatus including: low concentration CO 2 An absorption unit having an alkali metal hydroxide solution inlet and containing low concentration CO 2 A first raw material inlet to be trapped, a first part of low concentration CO 2 Absorption liquid outlet, second part low concentration CO 2 An absorption liquid outlet, a first exhaust gas outlet; low concentration CO 2 The absorption unit is used for capturing low-concentration CO by using alkali metal hydroxide solution 2 Obtaining low concentration CO 2 Absorption liquid, low concentration CO 2 The absorption liquid contains alkali metal carbonate and alkali metal hydroxide; high concentration CO 2 An absorption unit having a first portion of low concentration CO 2 An absorption liquid inlet containing high concentration CO 2 Is high in concentration and is imported from the second raw material to be trappedCO 2 An absorption liquid outlet, a second exhaust gas outlet; first part of low concentration CO 2 Absorption liquid inlet and first part of low concentration CO 2 The absorption liquid outlet is connected; high concentration CO 2 The absorption unit is used for utilizing the first part of low-concentration CO 2 The absorption liquid captures high-concentration CO 2 Obtaining high concentration CO 2 Absorption liquid, high concentration CO 2 The absorption liquid contains alkali carbonate and alkali bicarbonate; an electrolysis unit with a catholyte inlet, a nonionic membrane, an anolyte inlet, a catholyte outlet, an anolyte outlet, H 2 Outlet, O 2 /CO 2 A mixed gas outlet; catholyte inlet and second portion of low concentration CO 2 The absorption liquid outlet is connected with the catholyte outlet which is connected with the alkali metal hydroxide solution inlet; anolyte inlet and high concentration CO 2 The absorption liquid outlet is connected; the electrolysis unit is used for electrolyzing the second part of low-concentration CO 2 Absorption liquid and high concentration CO 2 Absorbing liquid, and obtaining H at an electrolytic cathode 2 And cathode liquid is discharged, O is obtained at the electrolysis anode 2 、CO 2 And an anode effluent, wherein the cathode effluent contains alkali metal carbonate and alkali metal hydroxide, and the anode effluent contains alkali metal carbonate and alkali metal bicarbonate.
Further, low concentration CO 2 The absorption unit includes: a low concentration absorption tower, the top of which is provided with an alkali metal hydroxide solution inlet and a first waste gas outlet, and the bottom of which is provided with a low concentration CO 2 A first raw material inlet to be trapped, a first part of low concentration CO 2 Absorption liquid outlet and second part of low concentration CO 2 An absorption liquid outlet; high concentration CO 2 The absorption unit includes: a high concentration absorption tower with a first part of low concentration CO at the top 2 An absorption liquid inlet and a second waste gas outlet, wherein the bottom of the high concentration absorption tower is provided with a high concentration CO 2 Is to be captured of the second raw material inlet and high concentration CO 2 And an absorption liquid outlet.
Further, the electrolysis unit includes: an electrolytic cell having a cathode chamber and an anode chamber with a nonionic membrane disposed therebetween,an electrolytic cathode is arranged in the cathode chamber, an electrolytic anode is arranged in the anode chamber, and the cathode chamber is provided with a catholyte inlet, a catholyte outlet and H 2 An outlet, the anode chamber is provided with an anode liquid inlet, an anode liquid outlet and O 2 /CO 2 And a mixed gas outlet.
Further, high concentration CO 2 The absorption unit further includes: high concentration CO 2 An absorption liquid tank arranged at the anode liquid inlet and high concentration CO 2 The absorption liquid outlet is connected with a pipeline and is positioned on the high-concentration CO 2 The side of the absorption liquid outlet.
Further, the electrolysis unit further includes: a cathode liquid inlet tank arranged at the cathode liquid inlet and the second part of low concentration CO 2 The absorption liquid outlet is connected with a pipeline; and/or a cathode liquid outlet tank which is arranged on a pipeline of the cathode liquid outlet connected with the alkali metal hydroxide solution inlet; and/or an anode liquid storage tank arranged at the anode liquid inlet and high concentration CO 2 The absorption liquid outlet is connected with the pipeline and is positioned at one side of the anode liquid inlet.
By applying the technical scheme of the invention, on one hand, the low-concentration and high-concentration CO is realized by taking the alkaline solution as the absorbent 2 Is of a broad concentration range of CO 2 Is absorbed and trapped. On the other hand, low-concentration and high-concentration CO is electrolyzed by using a nonionic membrane 2 The absorption product is coupled to produce hydrogen, so that the regeneration of absorption liquid can be realized, and high-concentration CO is obtained 2 And get H 2 、O 2 Additional products. The invention adopts low concentration CO 2 Absorbing liquid is used as cathode electrolyte, and high-concentration CO 2 The absorption liquid is used as anode electrolyte, and cathode CO is electrolyzed under the condition of not using an ionic membrane 3 2- The concentration increase can inhibit the diffusion of substances caused by concentration difference, thereby reducing the HCO of the electrolysis anode 3 -、CO 3 2- Diffusion to the cathode; CO with higher charge 3 2- In preference to OH - Electromigration occurs, thereby reducing its electromigration toward the anode. The electrolysis of the working medium liquid after capturing carbon dioxide can realize the regeneration of the alkaline absorption liquid to obtain high-purity product gas and the recycling of the capturing liquid,the regeneration cost of the absorption liquid is reduced. In addition, the use of the non-ionic membrane greatly reduces the cost of the electrolytic cell, avoids the severe restriction of the ionic membrane on the electrolyte and the electrolytic cell, and simplifies CO 2 The impurity removal and purification process of the absorption liquid further reduces CO 2 And (5) collecting cost. In summary, the method of the invention can realize a wide concentration range of CO 2 Is trapped, uses a nonionic membrane to carry out electrolysis to realize regeneration of absorption liquid and coupling hydrogen production, and can reduce CO in a wide concentration range 2 Trapping costs and obtaining H 2 、O 2 And simultaneously reduces the hydrogen production cost.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:
FIG. 1 shows a CO according to one embodiment of the invention 2 Schematic diagram of a trap coupled hydrogen plant.
Wherein the above figures include the following reference numerals:
1. low concentration CO 2 An absorption unit; 2. high concentration CO 2 An absorption unit; 3. an electrolysis unit; 11. a low concentration absorption tower; 21. a high-concentration absorption tower; 22. high concentration CO 2 An absorption liquid tank; 31. an electrolytic cell; 32. an anode liquid storage tank; 33. a cathode liquid inlet tank; 34. cathode liquid outlet tank; 311. a cathode chamber; 312. an anode chamber; 313. a non-ionic separator.
Detailed Description
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The invention will be described in detail below with reference to the drawings in connection with embodiments.
It should be noted that the terms "first," "second," and the like in the description and in the claims are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate in order to describe the embodiments of the invention herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus. Furthermore, the terms "more, less, medium, low concentration, high concentration" in relation to solutions in the description and claims of the present invention are used to denote relatively high concentrations, relatively low concentrations, and relatively intermediate concentrations in different steps of the relevant solutions and are not limited to a specific concentration level.
It is to be noted that the term "low concentration CO" in the description and claims of the present invention 2 "and" high concentration CO 2 "just to distinguish different COs 2 CO-containing at concentration 2 Materials, e.g. "low CO concentration 2 "may refer to carbon dioxide at a volume concentration of 1% or less (e.g., CO in air) 2 ) "high concentration CO 2 "may refer to a carbon dioxide volume concentration of 1% or more (e.g., CO in flue gas 2 ). Wherein "1%" is not distinguishing low concentration CO 2 And high concentration CO 2 But are merely exemplary, and may be adjusted during actual operation according to actual conditions.
The term "solution" as used herein refers to an aqueous solution unless otherwise specified.
As described in the background of the invention, there is a wide concentration range of CO in the prior art 2 The trapping cost and the hydrogen production cost are both high. In order to solve the above problems, in an exemplary embodiment of the present invention, there is provided a method of producing hydrogen by carbon capture coupling, comprising the steps of: step S1, capturing low concentration CO with alkali metal hydroxide solution 2 Obtaining low concentration CO 2 Absorption liquid, low concentration CO 2 The absorption liquid contains alkali metal carbonate and alkali metal hydroxide; step S2, low concentration CO 2 The absorption liquid is divided into a first part of low-concentration CO 2 Absorption liquid and second part of low concentration CO 2 Absorption liquid utilizing first part of low concentration CO 2 The absorption liquid captures high-concentration CO 2 Obtaining high concentration CO 2 Absorption liquid, high concentration CO 2 The absorption liquid contains alkali carbonate and alkali bicarbonate; step S3, the second part of low concentration CO 2 The absorption liquid is used as cathode liquid, and high concentration CO 2 The absorption liquid is used as anode liquid, the nonionic diaphragm is used as diaphragm for electrolysis, and H is obtained at the electrolysis cathode 2 And cathode liquid is discharged, O is obtained at the electrolysis anode 2 、CO 2 And anode liquid is discharged, the cathode liquid is returned to the step S1, the cathode liquid contains alkali metal carbonate and alkali metal hydroxide, and the anode liquid contains alkali metal carbonate and alkali metal bicarbonate.
The invention firstly utilizes alkali metal hydroxide solution to trap low-concentration CO 2 Obtaining low concentration CO containing alkali metal carbonate-alkali metal hydroxide 2 An absorption liquid in which the alkali metal hydroxide is not sufficiently converted into the alkali metal hydroxide; the first part of low concentration CO is then 2 Absorption liquid for capturing high-concentration CO 2 Obtaining high concentration CO of alkali metal carbonate-alkali metal bicarbonate containing a small amount of alkali metal bicarbonate 2 Absorbing liquid for realizing low and high concentration and wide range CO 2 Is absorbed and trapped; another part of low concentration CO 2 The absorption liquid is used as a cathode electrolyte, and high-concentration CO 2 The absorption liquid is used as an anode electrolyte, the nonionic diaphragm is used as an electrolysis diaphragm to electrolyze, and the low-concentration CO containing alkali carbonate and alkali hydroxide is prepared 2 The absorption liquid generates hydrogen evolution reaction at the cathode to generate H 2 At the same time, alkali metal ions in the anolyte enter the electrolytic cathode across the diaphragm under the action of electric field force and react with water molecules to generate OH by hydrogen evolution reduction - Forming regenerated alkali metal hydroxide, obtaining alkali metal carbonate-alkali metal hydroxide mixed solution with increased alkali metal hydroxide concentration at an electrolysis cathode, and obtaining O at an anode of an electrolysis tank 2 And CO 2 And an alkali metal carbonate-alkali metal bicarbonate regenerant.
On the one hand, by taking alkaline solution as absorbent, low-concentration and high-concentration CO is realized 2 Is of a broad concentration range of CO 2 Is absorbed and trapped. On the other hand, low-concentration and high-concentration CO is electrolyzed by using a nonionic membrane 2 The absorption product is coupled to produce hydrogen, so that the regeneration of absorption liquid can be realized, and high-concentration CO is obtained 2 And get H 2 、O 2 Additional products. The invention adopts low concentration CO 2 Absorbing liquid is used as cathode electrolyte, and high-concentration CO 2 The absorption liquid is used as anode electrolyte, and cathode CO is electrolyzed under the condition of not using an ionic membrane 3 2- The concentration increase can inhibit the diffusion of substances caused by concentration difference, thereby reducing the HCO of the electrolysis anode 3 -、CO 3 2- Diffusion to the cathode; CO with higher charge 3 2- In preference to OH - Electromigration occurs, thereby reducing its electromigration toward the anode. The electrolyte of the working medium liquid after capturing carbon dioxide can realize the regeneration of the alkaline absorption liquid, obtain high-purity product gas, realize the recycling of the capturing liquid and reduce the regeneration cost of the absorption liquid. In addition, the use of the non-ionic membrane greatly reduces the cost of the electrolytic cell, avoids the severe restriction of the ionic membrane on the electrolyte and the electrolytic cell, and simplifies CO 2 The impurity removal and purification process of the absorption liquid further reduces CO 2 And (5) collecting cost. In summary, the method of the invention can realize a wide concentration range of CO 2 Is trapped, uses a nonionic membrane to carry out electrolysis to realize regeneration of absorption liquid and coupling hydrogen production, and can reduce CO in a wide concentration range 2 Trapping costs and obtaining H 2 、O 2 And simultaneously reduces the hydrogen production cost.
The alkali metal of the present invention may be used Li, na, K, rb for further enhancing CO 2 Absorption and absorption of electrolyte electrolysis and further cost reduction purposes, the alkali metal is preferably K or Na, in a preferred embodiment the alkali metal hydroxide is KOH and the alkali metal carbonate is K 2 CO 3 The alkali metal bicarbonate is KHCO 3 The method comprises the steps of carrying out a first treatment on the surface of the Or the alkali metal hydroxide is NaOH, and the alkali metal carbonate is Na 2 CO 3 Alkali metalThe bicarbonate is NaHCO 3 . Taking alkali metal hydroxide as KOH for example, the method of the invention works as follows:
low concentration CO 2 And (3) capturing: CO 2 +2KOH→K 2 CO 3 +H 2 O, KOH is not completely converted to obtain KOH-K 2 CO 3 The solution was mixed.
High concentration CO 2 And (3) capturing: CO 2 +KOH→KHCO 3 The remaining KOH is completely converted to obtain K 2 CO 3 -KHCO 3 The solution was mixed.
And (3) electrolysis:
cathode reaction: 4H (4H) 2 O+4K + +4e - →2H 2 +4KOH。
Anode reaction: 2K 2 CO 3 -4e - →4K + +O 2 +2CO 2 。
Total reaction of electrolysis: 2K 2 CO 3 +4H 2 O→4KOH+2H 2 +O 2 +2CO 2 。
To achieve low concentration of CO 2 The absorption liquid is distributed more reasonably, in a preferred embodiment, in step S2, the first portion of low concentration CO, in volume percent 2 The absorption liquid is low-concentration CO 2 10-90% of the absorption liquid is treated with high concentration CO by containing a proper amount of unreacted alkali metal hydroxide 2 Trapping, thereby enabling high concentration CO as anolyte 2 Absorption liquid and low concentration CO as catholyte 2 The electrolytic volume of the absorption liquid is more adapted.
In a preferred embodiment, step S3 further comprises: and taking the anode liquid as anode liquid to electrolyze, thereby realizing the recycling of the anode liquid. Preferably, the concentration of carbonate in the catholyte is 0.1-6M, and the concentration of hydroxide is 0.1-10M; more preferably, the concentration of carbonate in the catholyte is 0.5-3M and the concentration of hydroxide is 3-7M; preferably, the concentration of carbonate in the anolyte is 0.1-6.5M, and the concentration of bicarbonate is 0.1-3M; more preferably, the concentration of carbonate in the anolyte is 2 to 5M, and the concentration of bicarbonate is0.6-1.5M, is more convenient for the alkali metal hydroxide solution to trap CO with wide concentration range 2 And the electrolysis process is rapidly carried out, and the increase of the electrolysis energy consumption caused by the overlarge ion concentration and the increase of the viscosity is avoided.
As described above, the method for producing hydrogen by carbon capture coupling of the invention adopts different concentrations of CO as the electrolyte catholyte and the anolyte 2 The absorption liquid can achieve good electrolysis effect without using high-cost ion exchange membrane, and avoids the severe limitation of using conditions of the ion membrane. In a preferred embodiment, the non-ionic membrane is one or more of a porous polymer membrane, a Zirfon membrane, a polyphenylene sulfide membrane, a polysulfone membrane, and a polyethersulfone membrane; preferably, the non-ionic membrane is a porous polymer membrane; more preferably, the surface polymer layer of the porous polymer membrane is one or more of carboxylate ion resin layer, polyphenylene sulfide, polysulfone and polyether sulfone, and carboxylate with negative charge and the like can assist in inhibiting cathode OH-from diffusing to anode, so that current efficiency is improved, and the non-ionic membrane can further reduce cost under the condition of ensuring electrolysis efficiency.
In yet another exemplary embodiment of the present invention, there is also provided a carbon capture coupled hydrogen plant, as shown in FIG. 1, comprising: low concentration CO 2 An absorption unit 1 having an alkali metal hydroxide solution inlet and containing CO at a low concentration 2 A first raw material inlet to be trapped, a first part of low concentration CO 2 Absorption liquid outlet, second part low concentration CO 2 An absorption liquid outlet, a first exhaust gas outlet; low concentration CO 2 The absorption unit 1 is used for capturing low-concentration CO by using alkali metal hydroxide solution 2 Obtaining low concentration CO 2 Absorption liquid, low concentration CO 2 The absorption liquid contains alkali metal carbonate and alkali metal hydroxide; high concentration CO 2 An absorption unit 2 having a first portion of low concentration CO 2 An absorption liquid inlet containing high concentration CO 2 Is characterized by comprising a second raw material inlet to be trapped and high-concentration CO 2 An absorption liquid outlet, a second exhaust gas outlet; first part of low concentration CO 2 Absorption liquid inlet and first part of low concentration CO 2 The absorption liquid outlet is connected; high concentration CO 2 The absorption unit 2 is used for utilizing a first part of low concentration CO 2 The absorption liquid captures high-concentration CO 2 Obtaining high concentration CO 2 Absorption liquid, high concentration CO 2 The absorption liquid contains alkali carbonate and alkali bicarbonate; an electrolysis unit 3 with a catholyte inlet, a nonionic membrane, an anolyte inlet, a catholyte outlet, an anolyte outlet, H 2 Outlet, O 2 /CO 2 A mixed gas outlet; catholyte inlet and second portion of low concentration CO 2 The absorption liquid outlet is connected with the catholyte outlet which is connected with the alkali metal hydroxide solution inlet; anolyte inlet and high concentration CO 2 The absorption liquid outlet is connected; the electrolysis unit 3 is used for electrolyzing the second part of low-concentration CO 2 Absorption liquid and high concentration CO 2 Absorbing liquid, and obtaining H at an electrolytic cathode 2 And cathode liquid is discharged, O is obtained at the electrolysis anode 2 、CO 2 And an anode effluent, wherein the cathode effluent contains alkali metal carbonate and alkali metal hydroxide, and the anode effluent contains alkali metal carbonate and alkali metal bicarbonate.
In use, the alkali metal hydroxide solution is used in low concentration CO 2 Capturing low concentration CO in the absorption unit 1 2 Obtaining low concentration CO containing alkali metal carbonate-alkali metal hydroxide 2 One part of the absorption liquid is led into the electrolytic cathode, and the other part is led into high-concentration CO 2 An absorption unit 2 for absorbing CO of high concentration 2 Obtaining high concentration CO of alkali metal carbonate-alkali metal bicarbonate containing a small amount of alkali metal bicarbonate 2 And (3) introducing the absorption liquid into an electrolysis anode for electrolysis. The mixed solution of alkali metal carbonate and alkali metal bicarbonate generates oxygen evolution reaction at the anode to obtain O 2 、CO 2 And a low-concentration alkali metal carbonate-medium-concentration alkali metal bicarbonate mixed solution, which is mixed with high-concentration CO 2 The absorption liquid is mixed and introduced into an anode liquid inlet device, and then circulated into the electrolysis unit 3. The mixed solution of alkali metal carbonate and alkali metal hydroxide generates hydrogen evolution reaction at the cathode to obtain H 2 And an alkali metal carbonate-alkali metal hydroxide catholyte with elevated alkali metal hydroxide concentration, followed by low concentration CO 2 The absorption unit 1 continues to capture low concentration CO 2 Low concentration CO 2 The mixed solution of the less alkali carbonate and the more alkali hydroxide in the absorption unit is treated by CO 2 Consuming to obtain mixed solution of multi-alkali metal carbonate and low-alkali metal hydroxide, wherein one part of the mixed solution enters an electrolytic cathode, and the other part of the mixed solution enters high-concentration CO 2 The absorption unit 2 is cyclically and continuously operated.
The device can realize a wide concentration range of CO 2 The gradient absorption of (2) is realized by using a nonionic membrane to carry out electrolysis so as to realize the regeneration of the absorption liquid KOH, and the CO with a wide concentration range can be reduced 2 Trapping cost and coupling hydrogen production to obtain H 2 、O 2 And the additional product of the method reduces the hydrogen production cost. Wherein the first part has a low concentration of CO 2 The flow rate of the absorption liquid can be regulated by a flow regulating valve.
Specifically, as shown in FIG. 1, in a preferred embodiment, the CO is at a low concentration 2 The absorption unit 1 includes: a low concentration absorption tower 11, wherein the top of the low concentration absorption tower 11 is provided with an alkali metal hydroxide solution inlet and a first waste gas outlet, and the bottom of the low concentration absorption tower 11 is provided with a low concentration CO 2 A first raw material inlet to be trapped, a first part of low concentration CO 2 Absorption liquid outlet and second part of low concentration CO 2 An absorption liquid outlet; high concentration CO 2 The absorption unit 2 includes: a high concentration absorption tower 21, the top of the high concentration absorption tower 21 is provided with a first part of low concentration CO 2 An absorption liquid inlet and a second exhaust gas outlet, the bottom of the high concentration absorption tower 21 is provided with a high concentration CO 2 Is to be captured of the second raw material inlet and high concentration CO 2 And an absorption liquid outlet.
In a preferred embodiment, the electrolysis unit 3 comprises: an electrolytic tank 31 having a cathode chamber 311 and an anode chamber 312, a nonionic membrane 313 disposed between the cathode chamber 311 and the anode chamber 312, an electrolytic cathode disposed in the cathode chamber 311, an electrolytic anode disposed in the anode chamber 312, and a cathode chamber 311 having a catholyte inlet, a catholyte outlet and H 2 An outlet, anode chamber 312 having an anolyte inlet, an anolyte outlet, and O 2 /CO 2 And a mixed gas outlet.
In a preferred embodiment, the CO is in a high concentration 2 The absorption unit 2 further includes: high concentration CO 2 An absorption liquid tank 22 arranged at the anode liquid inlet and high concentration CO 2 The absorption liquid outlet is connected with a pipeline and is positioned on the high-concentration CO 2 The side of the absorption liquid outlet.
In a preferred embodiment, the electrolysis unit 3 further comprises: a catholyte tank 33 disposed at the catholyte inlet and a second portion of the low concentration CO 2 The absorption liquid outlet is connected with a pipeline; and/or a catholyte outlet tank 34 disposed on a conduit connecting the catholyte outlet to the alkali metal hydroxide solution inlet; and/or an anolyte reservoir 32 disposed at the anolyte inlet and high concentration CO 2 The absorption liquid outlet is connected with the pipeline and is positioned at one side of the anode liquid inlet.
Wherein the catalyst contains low concentration CO 2 Is fed into an absorption tower 11, is trapped by an alkali metal hydroxide solution fed into the absorption tower 11, and is discharged to obtain a first waste gas B1, and low-concentration CO containing alkali metal carbonate-alkali metal hydroxide is obtained 2 Part of the absorption liquid is led into a cathode liquid inlet tank 33 and then enters a cathode chamber 311 for electrolysis; another part is led into an absorption tower 22 to collect CO with high concentration 2 The second raw material A2 to be trapped is discharged to obtain second waste gas B2, and high-concentration CO of alkali carbonate-alkali bicarbonate containing a small amount of alkali bicarbonate is obtained 2 Absorbing liquid and introducing high-concentration CO 2 The absorber fluid tank 22 then enters the anode reservoir tank 32 and ultimately the anode chamber 312 for electrolysis.
Wherein, the cathode chamber 311 generates hydrogen evolution reaction to obtain H 2 And the alkali metal carbonate-alkali metal hydroxide cathode liquid with the concentration of the alkali metal hydroxide increased enters a cathode liquid outlet tank 34 and returns to the absorption tower 11 to continuously capture low-concentration CO 2 . The anode chamber 312 undergoes an oxygen evolution reaction to yield O 2 、CO 2 And the low-concentration alkali metal carbonate-medium-concentration alkali metal bicarbonate mixed solution enter the anode liquid storage tank 32 and circulate into the anode chamber 312 for electrolysis.
The catholyte and anolyte may be made by supplementing waterAnd/or adjusting the mixing ratio to control the proper concentration to further improve the electrolysis efficiency. In addition, the catholyte contains K with a certain concentration 2 CO 3 (> 0.5M), cathode CO 3 2- Can reduce and/or inhibit anode HCO 3 - 、CO 3 2- Diffusion to the cathode is not completely avoided, so in a preferred embodiment, when electrolysis is not performed, catholyte and anolyte are pumped out of the cell. In the anode liquid storage tank, anode liquid and high-concentration CO 2 The proportion of the absorption liquid can be (0.2-2): 1, which is more convenient for the cycle of the electrolysis process.
The method and the device for preparing the hydrogen by carbon capture coupling have wide application prospect, and the application fields comprise: CO 2 Fields of trapping and utilization, hydrogen energy, etc., and application scenarios that may be involved include, but are not limited to: firstly, in areas rich in renewable energy sources such as wind energy, solar energy and the like, suitable for building nuclear power plant areas, the energy sources are utilized to generate electricity and are used for capturing CO in the air 2 Can fully utilize various energy sources and simultaneously reduce CO in the atmosphere 2 The content is as follows. Secondly, the industrial flue gas of the power plant, the cement plant, the metallurgical plant and the like contains a large amount of CO 2 And medium-low temperature waste heat, the invention is applied to the industrial field, and the flue gas waste heat is used as a regeneration heat source of an alkaline solution absorbent, so that CO can be carried out without an additional heat source 2 Trapping to realize industrial energy conservation and CO 2 The double aim of emission reduction is achieved, and meanwhile, the byproduct hydrogen can be obtained. Thirdly, the gas product of the invention is used in the energy storage field of renewable energy sources such as wind energy, solar energy and the like, and comprises CO 2 And H 2 The invention can be used for synthesizing secondary fuel such as methanol, and when the invention is used in the energy storage field, renewable energy sources can be converted into fuel chemical energy for storage, and the problems of renewable energy source energy storage stability, timeliness, transportation and the like are solved.
The present application is described in further detail below in conjunction with specific embodiments, which should not be construed as limiting the scope of the claims.
Example 1
CO of example 1 2 Trapping couplerThe combined hydrogen plant is shown in figure 1.
Containing low concentration CO 2 Is fed into absorption tower 11, is trapped by KOH solution fed into the absorption tower to obtain first waste gas B1 and is discharged to obtain K-containing gas 2 CO 3 Low concentration of CO of KOH 2 Part of the absorption liquid is led into a cathode liquid inlet tank 33 and then enters a cathode chamber 311 for electrolysis; another part is led into an absorption tower 22 to collect CO with high concentration 2 Is discharged by the second waste gas B2 to obtain the low KHCO content 3 K of (2) 2 CO 3 -KHCO 3 High concentration CO 2 Absorbing liquid and introducing high-concentration CO 2 The absorber fluid tank 22 then enters the anode reservoir tank 32 and ultimately the anode chamber 312 for electrolysis.
The cathode chamber 311 generates hydrogen evolution reaction to obtain H 2 And K with increased KOH concentration 2 CO 3 The KOH cathode liquid enters a cathode liquid outlet tank 34 and returns to the absorption tower 11 to continuously collect low-concentration CO 2 . The anode chamber 312 undergoes an oxygen evolution reaction to yield O 2 、CO 2 And low concentration K 2 CO 3 -intermediate concentration KHCO 3 The mixed solution enters the anode reservoir 32 and circulates into the anode chamber 312 for electrolysis. The electrolytic membrane is a porous polymer membrane with a carboxylate ion resin layer polymerized on the surface.
Wherein the first part has a low concentration of CO 2 The absorption liquid is low-concentration CO 2 50% of absorption liquid, cathode liquid 2M K 2 CO 3 Mixed solution with 5M KOH, anolyte of 3M K 2 CO 3 With 1M KHCO 3 Is a mixed solution of (a) and (b).
Example 2
Examples 2 to 6 differ from example 1 in the concentration of ions in the catholyte and anolyte, as detailed in table 1.
TABLE 1
Example 7
Example 7 differs from example 1 in thatA part of low concentration CO 2 The absorption liquid is low-concentration CO 2 10% of absorption liquid.
Example 8
Example 8 differs from example 1 in that the first portion of low concentration CO 2 The absorption liquid is low-concentration CO 2 90% of the absorption liquid.
Comparative example 1
Capturing CO with aqueous KOH solution over a wide concentration range 2 Obtaining K 2 CO 3 Electrolytic membrane is made of ion exchange resin film, KHCO is generated at anode 3 、K 2 CO 3 Mixed solution and CO 2 /O 2 Mixed gas, cathode to obtain H 2 And regenerating the KOH solution.
Examples 1 to 8 and comparative examples 1 to 2 were each at 2000A/m 2 Electrolysis was carried out at current density (Faraday efficiency 100%) with CO 2 When the collection amount is 1kg, H 2 Yield, O 2 The yield, KOH regeneration and electrolysis energy consumption are shown in Table 2.
TABLE 2
As can be seen from the above, the examples use the CO of the present invention 2 Trapping coupling hydrogen production method and device, and low-concentration and high-concentration CO is realized by taking alkaline solution as absorbent 2 Is of a broad concentration range of CO 2 Is absorbed and trapped. Simultaneously uses a non-ionic membrane to electrolyze low-concentration and high-concentration CO 2 Absorbing the product and coupling to produce hydrogen to realize the regeneration of the absorption liquid and obtain high-concentration CO 2 And get H 2 、O 2 Additional products. The invention adopts low concentration CO 2 Absorbing liquid is used as cathode electrolyte, and high-concentration CO 2 Absorbing liquid is used as anode electrolyte for electrolyzing cathode CO 3 2- Concentration increaseCan inhibit the diffusion of substances caused by concentration difference, thereby reducing the HCO of the electrolytic anode 3 -、CO 3 2- Diffusion to the cathode; CO with higher charge 3 2- In preference to OH - Electromigration occurs, so that electromigration towards the anode is reduced, an ionic membrane is not needed, the cost of the electrolytic tank is greatly reduced, the severe limitation of an ionic membrane on electrolyte and the electrolytic tank is avoided, the recycling of the collected liquid and the regeneration of alkaline absorption liquid are realized, and the CO is further reduced 2 And (5) collecting cost. In summary, the method of the invention can realize a wide concentration range of CO 2 Is trapped, uses a nonionic membrane to carry out electrolysis to realize regeneration of absorption liquid and coupling hydrogen production, and can reduce CO in a wide concentration range 2 Trapping costs and obtaining H 2 、O 2 And simultaneously reduces the hydrogen production cost.
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. A method for producing hydrogen by carbon capture coupling, comprising the steps of:
step S1, capturing low concentration CO with alkali metal hydroxide solution 2 Obtaining low concentration CO 2 Absorption liquid of low concentration CO 2 The absorption liquid contains alkali metal carbonate and the alkali metal hydroxide;
step S2, the low concentration CO is processed 2 The absorption liquid is divided into a first part of low-concentration CO 2 Absorption liquid and second part of low concentration CO 2 An absorption liquid utilizing the first portion of low concentration CO 2 The absorption liquid captures high-concentration CO 2 Obtaining high concentration CO 2 Absorption liquid of high concentration CO 2 The absorption liquid contains the alkali metal carbonate and the alkali metal bicarbonate;
step S3, the second part is low-concentrationCO 2 The absorption liquid is used as cathode liquid, and the high-concentration CO is treated 2 The absorption liquid is used as anode liquid, the nonionic diaphragm is used as diaphragm for electrolysis, and H is obtained at the electrolysis cathode 2 And cathode liquid is discharged, O is obtained at the electrolysis anode 2 、CO 2 And anode effluent, returning the cathode effluent to the step S1, wherein the cathode effluent contains the alkali metal carbonate and the alkali metal hydroxide, and the anode effluent contains the alkali metal carbonate and the alkali metal bicarbonate.
2. The method of claim 1, wherein the alkali metal hydroxide is KOH and the alkali metal carbonate is K 2 CO 3 The alkali metal bicarbonate is KHCO 3 The method comprises the steps of carrying out a first treatment on the surface of the Or alternatively
The alkali metal hydroxide is NaOH, and the alkali metal carbonate is Na 2 CO 3 The alkali metal bicarbonate is NaHCO 3 。
3. The method according to claim 1 or 2, wherein in step S2, the first fraction of low concentration CO is calculated as a percentage by volume 2 The absorption liquid is the low-concentration CO 2 10-90% of absorption liquid.
4. A method according to any one of claims 1 to 3, wherein step S3 further comprises: taking the anolyte as the anolyte to carry out electrolysis;
preferably, the concentration of carbonate in the catholyte is 0.1-6M, and the concentration of hydroxide is 0.1-10M; more preferably, the concentration of carbonate in the catholyte is 0.5-3M, and the concentration of hydroxide is 3-7M;
preferably, the concentration of carbonate in the anolyte is 0.1-6.5M, and the concentration of bicarbonate is 0.1-3M; more preferably, the concentration of carbonate in the anolyte is 2 to 5M, and the concentration of bicarbonate is 0.6 to 1.5M.
5. The method of any one of claims 1 to 4, wherein the non-ionic membrane is one or more of a porous polymer membrane, a Zirfon membrane, a polyphenylene sulfide membrane, a polysulfone membrane, and a polyethersulfone membrane; preferably, the nonionic membrane is a porous polymer membrane; more preferably, the surface polymer layer of the porous polymer membrane is one or more of a carboxylate ion resin layer, polyphenylene sulfide, polysulfone, and polyethersulfone.
6. A carbon-trap coupled hydrogen production device, comprising:
low concentration CO 2 An absorption unit (1) having an alkali metal hydroxide solution inlet and containing CO at a low concentration 2 A first raw material inlet to be trapped, a first part of low concentration CO 2 Absorption liquid outlet, second part low concentration CO 2 An absorption liquid outlet, a first exhaust gas outlet; the low concentration CO 2 The absorption unit (1) is used for capturing low-concentration CO by using alkali metal hydroxide solution 2 Obtaining low concentration CO 2 Absorption liquid of low concentration CO 2 The absorption liquid contains alkali metal carbonate and the alkali metal hydroxide;
high concentration CO 2 An absorption unit (2) having a first portion of low concentration CO 2 An absorption liquid inlet containing high concentration CO 2 Is characterized by comprising a second raw material inlet to be trapped and high-concentration CO 2 An absorption liquid outlet, a second exhaust gas outlet; the first part has low concentration CO 2 An absorption liquid inlet and the first part of low-concentration CO 2 The absorption liquid outlet is connected; the high concentration CO 2 An absorption unit (2) for utilizing the first part of low concentration CO 2 The absorption liquid captures high-concentration CO 2 Obtaining high concentration CO 2 Absorption liquid of high concentration CO 2 The absorption liquid contains the alkali metal carbonate and the alkali metal bicarbonate;
an electrolysis unit (3) provided with a catholyte inlet, a nonionic membrane, an anolyte inlet, a catholyte outlet, an anolyte outlet, an H 2 Outlet, O 2 /CO 2 A mixed gas outlet; the catholyte inlet and the second portion of low concentration CO 2 The absorption liquid outlet is connected with the catholyte outlet and the alkali metal hydroxide solution inlet; the anolyte inlet and the high-concentration CO 2 The absorption liquid outlet is connected; the electrolysis unit (3) is used for electrolyzing the second part of low-concentration CO 2 Absorption liquid and said high concentration CO 2 Absorbing liquid, and obtaining H at an electrolytic cathode 2 And cathode liquid is discharged, O is obtained at the electrolysis anode 2 、CO 2 And an anode effluent, wherein the cathode effluent contains the alkali metal carbonate and the alkali metal hydroxide, and the anode effluent contains the alkali metal carbonate and the alkali metal bicarbonate.
7. The apparatus of claim 6, wherein the device comprises a plurality of sensors,
the low concentration CO 2 The absorption unit (1) comprises: a low concentration absorption tower (11), wherein the top of the low concentration absorption tower (11) is provided with the alkali metal hydroxide solution inlet and the first waste gas outlet, and the bottom of the low concentration absorption tower (11) is provided with the low concentration CO 2 Is a first raw material inlet to be trapped, the first part of low concentration CO 2 Absorption liquid outlet and said second portion of low concentration CO 2 An absorption liquid outlet;
the high concentration CO 2 The absorption unit (2) comprises: a high concentration absorption tower (21), wherein the top of the high concentration absorption tower (21) is provided with the first part of low concentration CO 2 An absorption liquid inlet and the second exhaust gas outlet, the bottom of the high concentration absorption tower (21) is provided with the high concentration CO 2 Is to be captured and the high concentration CO 2 And an absorption liquid outlet.
8. The device according to claim 6 or 7, characterized in that the electrolysis unit (3) comprises:
an electrolytic tank (31) having a cathode chamber (311) and an anode chamber (312), wherein the nonionic membrane (313) is arranged between the cathode chamber (311) and the anode chamber (312), an electrolytic cathode is arranged in the cathode chamber (311), an electrolytic anode is arranged in the anode chamber (312), anda cathode chamber (311) having the catholyte inlet, the catholyte outlet and the H 2 An outlet, the anode chamber (312) having the anolyte inlet, the anolyte outlet, the O 2 /CO 2 And a mixed gas outlet.
9. The apparatus according to any one of claims 6 to 8, wherein the high concentration CO 2 The absorption unit (2) further comprises: high concentration CO 2 An absorption liquid tank (22) provided at the anolyte inlet and the high concentration CO 2 The absorption liquid outlet is connected with a pipeline and is positioned on the high-concentration CO 2 The side of the absorption liquid outlet.
10. The apparatus according to any one of claims 6 to 9, wherein the electrolysis unit (3) further comprises:
a catholyte inlet tank (33) disposed at the catholyte inlet and the second portion of low concentration CO 2 The absorption liquid outlet is connected with a pipeline; and/or
A cathode liquid outlet tank (34) arranged on a pipeline of the cathode liquid outlet connected with the alkali metal hydroxide solution inlet; and/or
An anode liquid storage tank (32) arranged at the anode liquid inlet and the high concentration CO 2 And the absorption liquid outlet is connected with a pipeline and is positioned at one side of the anode liquid inlet.
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