CN116839310A - Process method for preparing food-grade liquid carbon dioxide by utilizing decarburization exhaust gas of LNG (liquefied Natural gas) plant - Google Patents
Process method for preparing food-grade liquid carbon dioxide by utilizing decarburization exhaust gas of LNG (liquefied Natural gas) plant Download PDFInfo
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- CN116839310A CN116839310A CN202310919917.0A CN202310919917A CN116839310A CN 116839310 A CN116839310 A CN 116839310A CN 202310919917 A CN202310919917 A CN 202310919917A CN 116839310 A CN116839310 A CN 116839310A
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- carbon dioxide
- desulfurization
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- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims abstract description 110
- 238000000034 method Methods 0.000 title claims abstract description 100
- 229910002092 carbon dioxide Inorganic materials 0.000 title claims abstract description 55
- 239000001569 carbon dioxide Substances 0.000 title claims abstract description 53
- 239000007788 liquid Substances 0.000 title claims abstract description 27
- 238000005261 decarburization Methods 0.000 title claims abstract description 9
- 239000007789 gas Substances 0.000 title claims description 281
- 239000003949 liquefied natural gas Substances 0.000 title description 30
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 94
- 230000023556 desulfurization Effects 0.000 claims abstract description 94
- 239000004215 Carbon black (E152) Substances 0.000 claims abstract description 37
- 229930195733 hydrocarbon Natural products 0.000 claims abstract description 37
- 150000002430 hydrocarbons Chemical class 0.000 claims abstract description 37
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims abstract description 36
- 238000001816 cooling Methods 0.000 claims abstract description 28
- 238000001035 drying Methods 0.000 claims abstract description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000001294 propane Substances 0.000 claims abstract description 18
- 238000006243 chemical reaction Methods 0.000 claims abstract description 16
- 230000003197 catalytic effect Effects 0.000 claims abstract description 9
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 9
- 230000000694 effects Effects 0.000 claims abstract description 7
- 230000003647 oxidation Effects 0.000 claims abstract description 6
- 230000003009 desulfurizing effect Effects 0.000 claims description 49
- 230000018044 dehydration Effects 0.000 claims description 38
- 238000006297 dehydration reaction Methods 0.000 claims description 38
- 239000003795 chemical substances by application Substances 0.000 claims description 33
- 230000007062 hydrolysis Effects 0.000 claims description 33
- 238000006460 hydrolysis reaction Methods 0.000 claims description 33
- 238000006900 dealkylation reaction Methods 0.000 claims description 29
- 230000020335 dealkylation Effects 0.000 claims description 21
- 229910052717 sulfur Inorganic materials 0.000 claims description 21
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 19
- 239000011593 sulfur Substances 0.000 claims description 19
- 238000001179 sorption measurement Methods 0.000 claims description 18
- 239000004229 Alkannin Substances 0.000 claims description 14
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 14
- 239000002151 riboflavin Substances 0.000 claims description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 12
- 229910052799 carbon Inorganic materials 0.000 claims description 12
- 238000000746 purification Methods 0.000 claims description 12
- 239000004172 quinoline yellow Substances 0.000 claims description 11
- 235000013305 food Nutrition 0.000 claims description 9
- 238000003860 storage Methods 0.000 claims description 9
- 239000002808 molecular sieve Substances 0.000 claims description 8
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims description 8
- 239000004149 tartrazine Substances 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 239000011787 zinc oxide Substances 0.000 claims description 7
- 239000004230 Fast Yellow AB Substances 0.000 claims description 6
- 239000003054 catalyst Substances 0.000 claims description 6
- 239000004234 Yellow 2G Substances 0.000 claims description 5
- 239000013543 active substance Substances 0.000 claims description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 4
- 239000012752 auxiliary agent Substances 0.000 claims description 4
- 229910052760 oxygen Inorganic materials 0.000 claims description 4
- 239000001301 oxygen Substances 0.000 claims description 4
- 239000000654 additive Substances 0.000 claims description 3
- 230000000996 additive effect Effects 0.000 claims description 3
- 230000001502 supplementing effect Effects 0.000 claims description 3
- 239000002075 main ingredient Substances 0.000 claims description 2
- 125000001741 organic sulfur group Chemical group 0.000 claims description 2
- 239000002994 raw material Substances 0.000 abstract description 34
- 238000005265 energy consumption Methods 0.000 abstract description 17
- 238000005057 refrigeration Methods 0.000 abstract description 16
- 238000004064 recycling Methods 0.000 abstract description 7
- 239000000498 cooling water Substances 0.000 abstract description 5
- 238000010438 heat treatment Methods 0.000 abstract description 5
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- 238000002485 combustion reaction Methods 0.000 abstract description 3
- 238000004134 energy conservation Methods 0.000 abstract description 3
- 239000000047 product Substances 0.000 description 25
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 20
- 239000003570 air Substances 0.000 description 15
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 14
- 230000006835 compression Effects 0.000 description 12
- 238000007906 compression Methods 0.000 description 12
- 238000001704 evaporation Methods 0.000 description 11
- 230000008020 evaporation Effects 0.000 description 11
- 230000008929 regeneration Effects 0.000 description 10
- 238000011069 regeneration method Methods 0.000 description 10
- 238000005516 engineering process Methods 0.000 description 9
- 239000003507 refrigerant Substances 0.000 description 8
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 7
- 239000003345 natural gas Substances 0.000 description 7
- 229910052757 nitrogen Inorganic materials 0.000 description 7
- 239000002699 waste material Substances 0.000 description 6
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 5
- 238000003795 desorption Methods 0.000 description 4
- PVXVWWANJIWJOO-UHFFFAOYSA-N 1-(1,3-benzodioxol-5-yl)-N-ethylpropan-2-amine Chemical compound CCNC(C)CC1=CC=C2OCOC2=C1 PVXVWWANJIWJOO-UHFFFAOYSA-N 0.000 description 3
- QMMZSJPSPRTHGB-UHFFFAOYSA-N MDEA Natural products CC(C)CCCCC=CCC=CC(O)=O QMMZSJPSPRTHGB-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 239000002826 coolant Substances 0.000 description 3
- 230000006378 damage Effects 0.000 description 3
- 238000005262 decarbonization Methods 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 238000011045 prefiltration Methods 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- -1 C 4 Alkane Chemical class 0.000 description 2
- 208000028571 Occupational disease Diseases 0.000 description 2
- 208000027418 Wounds and injury Diseases 0.000 description 2
- 239000003463 adsorbent Substances 0.000 description 2
- 150000001335 aliphatic alkanes Chemical class 0.000 description 2
- 239000012080 ambient air Substances 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000005494 condensation Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 239000000110 cooling liquid Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 230000003301 hydrolyzing effect Effects 0.000 description 2
- 208000014674 injury Diseases 0.000 description 2
- 238000011900 installation process Methods 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 239000012263 liquid product Substances 0.000 description 2
- 229910000510 noble metal Inorganic materials 0.000 description 2
- 241000251468 Actinopterygii Species 0.000 description 1
- 229930182555 Penicillin Natural products 0.000 description 1
- JGSARLDLIJGVTE-MBNYWOFBSA-N Penicillin G Chemical compound N([C@H]1[C@H]2SC([C@@H](N2C1=O)C(O)=O)(C)C)C(=O)CC1=CC=CC=C1 JGSARLDLIJGVTE-MBNYWOFBSA-N 0.000 description 1
- 239000004231 Riboflavin-5-Sodium Phosphate Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 235000013361 beverage Nutrition 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000006071 cream Substances 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000006356 dehydrogenation reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 235000015243 ice cream Nutrition 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 229940049954 penicillin Drugs 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
- F25J1/006—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the refrigerant fluid used
- F25J1/0095—Oxides of carbon, e.g. CO2
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
- F25J3/0266—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of carbon dioxide
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
- F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
- F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
- F25J1/0257—Construction and layout of liquefaction equipments, e.g. valves, machines
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/40—Features relating to the provision of boil-up in the bottom of a column
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/70—Refluxing the column with a condensed part of the feed stream, i.e. fractionator top is stripped or self-rectified
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/74—Refluxing the column with at least a part of the partially condensed overhead gas
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2210/00—Processes characterised by the type or other details of the feed stream
- F25J2210/70—Flue or combustion exhaust gas
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2215/00—Processes characterised by the type or other details of the product stream
- F25J2215/04—Recovery of liquid products
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2220/00—Processes or apparatus involving steps for the removal of impurities
- F25J2220/80—Separating impurities from carbon dioxide, e.g. H2O or water-soluble contaminants
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2220/00—Processes or apparatus involving steps for the removal of impurities
- F25J2220/80—Separating impurities from carbon dioxide, e.g. H2O or water-soluble contaminants
- F25J2220/82—Separating low boiling, i.e. more volatile components, e.g. He, H2, CO, Air gases, CH4
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2220/00—Processes or apparatus involving steps for the removal of impurities
- F25J2220/80—Separating impurities from carbon dioxide, e.g. H2O or water-soluble contaminants
- F25J2220/84—Separating high boiling, i.e. less volatile components, e.g. NOx, SOx, H2S
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
- F25J2230/30—Compression of the feed stream
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2270/00—Refrigeration techniques used
- F25J2270/12—External refrigeration with liquid vaporising loop
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2270/00—Refrigeration techniques used
- F25J2270/60—Closed external refrigeration cycle with single component refrigerant [SCR], e.g. C1-, C2- or C3-hydrocarbons
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Separation By Low-Temperature Treatments (AREA)
Abstract
The invention discloses a process method for preparing food-grade liquid carbon dioxide by utilizing decarburization exhaust gas of an LNG factory, which belongs to the technical field of preparing food-grade liquid carbon dioxide and comprises the following steps of: s1: a desulfurization step; s2: a hydrocarbon removal conversion step; s3, dehydrating and drying; s4: and (3) rectifying and liquefying. The beneficial effects are that: the cold energy of the atmospheric environment is fully utilized, and the circulating water is not needed, so that the consumption of the circulating water is reduced by 100 percent. The catalytic oxidation combustion heat is fully utilized, 46.43% of traditional heating energy sources are reduced, and the energy-saving and emission-reducing device has very important effects on energy conservation and emission reduction; the consumption of raw material gas and circulating cooling water is reduced, so that energy is saved and consumption is reduced; the temperature of the raw material drying gas is reduced, the cold load of a propane refrigeration system is reduced, the setting of a pre-cooling heat exchanger in front of a tower is reduced, the most economical energy recycling is realized, and the energy consumption and the equipment investment are reduced.
Description
Technical Field
The invention belongs to the technical field of preparing food-grade liquid carbon dioxide, and particularly relates to a process method for preparing food-grade liquid carbon dioxide by utilizing decarburization exhaust gas of an LNG factory.
Background
Carbon dioxide is widely used in petrochemical industry, chemical fertilizer, welding, fire control, and oil exploitation, and liquid carbon dioxide is stockThe carbon dioxide is widely applied to the aspects of food refrigeration and beverage carbonation, and the high-purity carbon dioxide is mainly used in the electronic industry, medical research, carbon dioxide lasers, detection instrument correction gas and other special mixed gas configuration, and the solid carbon dioxide is also widely applied to the fields of penicillin production, storage of fish, cream, ice cream and other foods, low-temperature transportation and the like. With the increasing demands of people on food quality and in order to reduce the greenhouse effect and the emission of carbon dioxide, the production of high-quality food-grade carbon dioxide is an important technical task; the raw material natural gas adopted by the LNG factory is one-class and two-class natural gas specified by the standard of natural gas GB 17820-2018. At present, an MDEA wet decarbonization process is adopted in an LNG factory decarbonization process, and CO in raw natural gas is adopted 2 And sulfur is discharged as noncondensable gas at the top of the MDEA tower. The direct high-point discharge of carbon dioxide and sulfur in the noncondensable gas and a small amount of hydrocarbon substances increases the pollutant discharge amount of the atmosphere and wastes certain raw material components; CO of decarbonized effluent gas of LNG plant 2 Trapping technology is becoming increasingly important.
The patent CN104474871A, named as a method for preparing LNG by recycling methanol tail gas, adopts purge gas MDEA wet decarburization, molecular sieve drying dehydration and dealkylation, single refrigerant nitrogen throttling expansion refrigeration cycle, cold box liquefaction and cold box rear end low temperature rectification technology to produce LNG, and adopts a 3-tower process isobaric temperature swing adsorption dehydration and heavy hydrocarbon except the molecular sieve dehydration in the prior art.
The patent CN114440551A, named as a device and a method for recycling mixed hydrocarbon of oilfield associated gas rich in nitrogen and liquefying dry gas at low temperature, adopts the processes of wet decarbonization, molecular sieve drying and dehydration and hydrocarbon removal, mixed refrigerant throttling expansion refrigeration cycle, cold box liquefaction and cold box section-to-section low temperature rectification for removing mixed hydrocarbon and nitrogen of the oilfield associated gas mixed hydrocarbon rich in nitrogen to produce LNG.
The disadvantages of the two prior art mentioned above are: because the 3-tower process isobaric temperature swing adsorption dehydration and heavy hydrocarbon engineering are adopted, the regenerated noncondensable gas is needed to be used as regenerated gas, so that the regenerated gas circulation can be achieved only by pressurizing by a compressor, and meanwhile, a regenerated gas cooler and a separator are needed to be arranged, so that the investment of 3 devices is increased, the energy consumption of the compressor and the consumption of circulating cooling water are increased, and meanwhile, the consumption of power electricity consumption and the consumption of cooling medium are increased due to the increase of the devices, and the regenerated heat is wasted.
The patent CN110801639A, named as a method for recovering carbon dioxide by multistage liquefaction and fractional refrigeration of industrial tail gas, adopts a method for condensing and liquefying purified feed gas at the temperature of 3.3MPa38 ℃, adopts liquid ammonia evaporation, is provided with 4 cold energy heat exchangers outside a rectifying tower (the feed gas firstly enters a first residual cold recoverer, exchanges heat with non-condensable gas and is precooled to the temperature of 22 ℃, then goes to a second residual cold recoverer, exchanges heat with non-condensable gas and is precooled to the temperature of 16 ℃, then goes to a first-stage condenser, is cooled to the temperature of minus 18 ℃ by ammonia evaporation refrigeration, then goes to a second-stage condenser, is cooled to the temperature of minus 25 ℃ by ammonia evaporation refrigeration again), and 1 reboiler and one product subcooler.
Patent CN110801639A, named as a method for recovering carbon dioxide by multistage liquefaction and fractional refrigeration of industrial tail gas, adopts a technology of preparing LCO2 by rectification of a rectifying tower,
the disadvantages of the two prior art mentioned above are: the regenerated gas cooler is needed, an economizer T103 is needed to be arranged outside the tower bottom of the fine stripping tower, in addition, 3 pieces of equipment such as a second residual cold recoverer T102, a primary condenser T104, a secondary condenser T105 and the like are needed, and in addition, 5 pieces of heat exchangers are needed to be additionally arranged, so that the equipment cost, the installation construction and the site occupation are uneconomical, and in terms of the process flow, the process flow needed by adopting the 3.3MPa technology in the prior art is longer, the equipment is needed to be additionally arranged, and the utilization of cold energy is unreasonable.
Patent CN114518016a, entitled "apparatus and method for capturing, liquefying and recovering carbon dioxide", adopts a technique of removing only H before compression in the desulfurization step 2 S, removing COS or removing COS in the liquefaction process is not considered; in the prior art of the dehydration procedure, the purified natural gas of the LNG factory is dehydrated by constant pressure variable temperature drying, which is thatThe regenerated gas cooler and the regenerated gas separator are required to be arranged for drying and dehydration; in the prior art of the liquefaction and rectification process, cold box liquefaction and rectification tower rectification secondary rectification liquefaction are adopted.
The above patent has several disadvantages:
1. problems of desulfurization process:
(1) Prior Art because of the sour gas CO removal in LNG plants 2 The low pressure of (2) and the uncompressed desulfurization lead to two problems: firstly, the desulfurization tower equipment has high resistance, so that the pressure of the front-end carbon dioxide desorption tower is increased, the pressure of the front-end LNG factory desorption tower has to be increased to meet the system requirement, thus increasing the heat source energy consumption of the desorption tower reboiler and reducing the CO of the carbon dioxide desorption tower 2 Resolving effect, leading to raw material natural gas CO 2 The absorption effect is reduced, the consumption of amine liquid is increased, and the energy consumption of the decarburization process of the LNG factory is increased; secondly, the operating pressure of the desulfurizing tower is low, the size of equipment is required to be increased, the occupied area of the equipment is required to be increased, and the equipment such as pipelines is required to be increased, so that the one-time investment is greatly increased.
(2) The prior art does not consider removing COS or removing COS in the liquefaction process, and the problems are as follows: since the boiling point of COS is-50 ℃, if separation rectification is adopted for removal in the carbon dioxide gas containing COS, secondary rectification is required, so that the cold energy consumption is increased, and the carbon dioxide recovery rate is reduced. In addition, the prior art adopts a liquefaction cold box and rectification secondary desulfurization, and two devices of a final stage cooler and a separator of the compressor are also required to be added.
2. Problems of dehydration process:
in the prior art, the purified natural gas of the LNG factory is dehydrated by adopting constant-pressure variable-temperature drying, a regenerated gas cooler and a regenerated gas separator are needed for drying and dehydration, if the hot regenerated gas of the original LNG factory is adopted, the pipeline loss can be generated on heat energy by taking the distance between an original device and a new device into consideration, the energy waste is caused, and in addition, the series-parallel connection of different systems can generate essential linkage hidden trouble on the system stability.
3. Problems of the liquefaction and rectification process:
in the prior art, cold box liquefaction and rectifying tower rectification secondary rectification liquefaction are adopted, so that equipment investment of a cold box system is required, and resistance loss of the cold box system can be generated, so that energy consumption of a dioxide compressor is caused, and the equipment investment is increased;
in the prior art, the carbon dioxide feed gas compressor adopts three-stage compression, and as the liquefaction adopts cold box and rectifying tower secondary rectifying liquefaction, the energy consumption is increased by 20% and the equipment is increased by 50%.
The mixed refrigerant throttling refrigeration of the LNG factory is adopted in the prior art, and has the potential hazards of intrinsic linkage of series-parallel connection of different systems on system stability.
In the technology, COS hydrolysis temperature in a desulfurization procedure is 60 ℃, a desulfurization heater and a desulfurization cooler are arranged, gas at an outlet of a compressor is heated to 60 ℃ by the desulfurization heater, enters a hydrolysis tower to hydrolyze COS, and then enters a desulfurization water cooler to cool to normal temperature to remove H generated by hydrolysis in a fine desulfurization tower 2 S, removing; in the hydrocarbon removal process, hydrocarbon removal is arranged between primary low-temperature condensation purification and secondary low-temperature rectification, and 1 desulfurization cooler and cooling circulating water are arranged; in the liquefaction process, a low-temperature precooling, primary low-temperature purification and secondary low-temperature rectification liquefaction process is adopted, and liquid ammonia evaporation refrigeration is adopted for cold energy.
The disadvantages of this patent are:
1. problems of desulfurization process: the hydrolyzing temperature of COS in the prior art is 60 ℃, so that a desulfurizing heater and a desulfurizing cooler are needed, the desulfurizing temperature is different, the gas at the outlet of a compressor in the prior art is heated to 60 ℃ by the desulfurizing heater, enters a hydrolyzing tower to hydrolyze COS, and then is cooled to normal temperature by the desulfurizing water cooler, and then H generated by hydrolysis is removed by a fine desulfurizing tower 2 S is removed, so that 4 devices such as a final stage cooler of a compressor, a separator, a desulfurization heater, a desulfurization cooler and the like are required to be additionally arranged, and the investment of the devices is increased.
2. Problems of the hydrocarbon removal process: the dealkylation is arranged between the first-stage low-temperature condensation purification and the second-stage low-temperature rectification, 1 desulfurization cooler and cooling circulating water are required to be additionally arranged, and the cold energy consumption is increased;
3. problems of the liquefaction process: the existing patent adopts low-temperature precooling, primary low-temperature purification and secondary low-temperature rectification liquefaction technology, and cold energy adopts liquid ammonia evaporation refrigeration, so that two devices of a low-temperature precooler and a primary purification tower are required to be added, and the investment is larger.
Patent CN107062798A, entitled "gas carbon dioxide liquefaction system and method", adopts a 3-column pressure swing adsorption dehydration process in the prior art, and only has dehydration and liquefaction processes.
Disadvantages of the prior art:
1. problems of dehydration process: in the prior art 3 towers of variable-pressure variable-temperature adsorption dehydration technology, 1 adsorption tower is more, and because one adsorption tower is more, the number of switching valves is more than 9, so that the one-time investment of equipment, pipeline valves, occupied land and the like is increased, the heat energy of regenerated gas in the prior art is not utilized to directly discharge the gas above 220 ℃ to the atmosphere, the ambient temperature of the surrounding atmosphere is increased, and the occupational disease hazard of high-temperature scalding is possibly increased.
2. Problems of rectification and liquefaction process: by CO 2 Refrigeration cycle due to CO 2 The refrigeration cycle requires a refrigeration efficiency characteristic of high system pressure, so that the prior art is CO 2 The raw material gas compressor adopts multistage compression to 5-7 MPa, which causes the problem of high energy consumption of the compressor, the carbon dioxide raw material gas compressor in the prior art adopts multistage compression (the outlet pressure is 5-7 MPa), the energy consumption is increased by 20% in the two-stage rectification liquefaction, and the equipment is increased by 50%.
In summary, the prior art can achieve the purpose of preparing carbon dioxide in several different ways, but in order to obtain a carbon dioxide product, there are basically different problems in different ways, and four main problems are summarized: firstly, the equipment is required, the occupied land is large, and the investment is increased; secondly, because of more equipment, the installation process is complex, the production process flow is long, and thirdly, the resource cannot be fully utilized, so that the problem of energy waste is caused; fourth, there are bad environmental results in terms of emissions and hidden dangers of injury to personnel and equipment. This is the technical problem to be solved by the present invention.
Disclosure of Invention
The technical problem to be solved by the invention is to solve the problems in the background technology.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the process of preparing food grade liquid carbon dioxide with decarbonizing effluent gas from LNG plant includes the following steps:
s1, desulfurization process:
the decarbonized LNG decarbonized exhaust gas is compressed by a two-stage compressor C101, the outlet of the first-stage compressor directly enters a fine desulfurization tower T101 to remove inorganic sulfur, and the desulfurized gas enters the two-stage compressor. The second-stage outlet gas of the compressor directly enters a second-stage medium-temperature hydrolysis desulfurization system without heat exchange, is subjected to hydrolysis and zinc oxide desulfurization sequentially through a first-stage fine desulfurization tower T102 and a second-stage fine desulfurization tower T103, and a high-efficiency fine desulfurizing agent is arranged at the bottommost end of the second-stage fine desulfurization tower T103, so that the total sulfur content in the finally desulfurized gas is 0.1PPm. The raw material gas is captured and stored in the desulfurizing agent under the action of the desulfurizing agent, so that the pollution to the environment is reduced.
The raw material gas (LNG decarburization effluent gas of a factory) is CO with the boundary pressure of 0.01-0.03 MPa (G) and the temperature of 45 DEG C 2 Raw material gas enters a first-stage buffer tank C101 at the inlet of a carbon dioxide compressor and passes through CO 2 After the primary compression of the compressor is boosted to 0.8-0.9 MPaG, the compressed gas sequentially passes through a first-stage cooler (an air cooler or a circulating water cooler, specifically determined according to meteorological data of the place), a first-stage separator is cooled to 40 ℃ after separation, compressed gas from the outlet of the first-stage separator of C101 enters a T101 fine desulfurization tower, and inorganic sulfur H is removed by an active carbon desulfurizing agent of the fine desulfurization tower T101 2 S, H in outlet desulfurization gas of T101 fine desulfurization tower 2 S concentration is less than or equal to 0.1PPm, and H is removed 2 The feed gas of S continues to return to C101 for continued compression. And the outlet gas of the C101 second-stage compressor enters a second-stage hydrolysis and fine desulfurization system for desulfurization at 120-140 ℃ after being pressurized to 2.5MPaG by the C101 second-stage compressor.
The gas from the second-stage outlet of the C101 enters a first-stage fine desulfurization tower T102 for first-stage hydrolysis desulfurization, a hydrolysis fine desulfurizing agent is arranged at the upper part of the T102, a zinc oxide fine desulfurizing agent is arranged at the lower part of the T102, the gas from the outlet of the bottom of the second-stage fine desulfurization tower T102 enters a T103 from the top of the T103 for second-stage hydrolysis fine desulfurization, a hydrolysis fine desulfurizing agent is arranged at the upper part of the T103, a zinc oxide fine desulfurizing agent is arranged at the middle part of the T103, a high-efficiency fine desulfurizing agent is arranged at the bottom, and the total sulfur content in the gas subjected to the second-stage hydrolysis fine desulfurization of the T103 is 0.1PPm.
S2: a hydrocarbon removal conversion step: the product obtained in step S1 contains C 1 ～C 4 Directly enters a tower heat exchanger E101 and a dealkylation heater E102 without cooling, and the product from the step S1 is converted into CO under the action of a dealkylation conversion catalyst 2 The temperature of the hydrocarbon-removed gas from the hydrocarbon-removal reactor R101 is reduced by passing through the inlet/outlet heat exchanger E101 and the air cooler E103.
The purified gas after hydrolysis desulfurization is directly subjected to catalytic oxidation hydrocarbon removal procedure without a desulfurization cooler to recycle gas heat energy. The desulfurization gas from T103 is 110-130 ℃, the pressure is 2.4MPaG, the desulfurization gas enters into a heat exchanger E101 of an inlet tower and a heat exchanger of an outlet tower and is heated with the outlet gas (430 ℃ and 2.3 MPaG) of a dealkylation reaction tower R101, then enters into an electric heater E102 to be heated to 400 ℃, and then enters into the dealkylation reaction tower R101, and the C in the raw material gas is 1 ～C 4 Alkane is subjected to catalytic oxidation reaction under the action of noble metal catalyst to generate CO 2 And H 2 O. After the reaction, C-C in the raw material gas 4 The alkane content is less than 1ppm. The dehydrogenated gas enters an air cooler E103 after passing through E101, is cooled to 50-60 ℃ by using the cold energy of the ambient air, and goes to the downstream dehydration and drying process.
S3, dehydration and drying steps: cooling the product obtained in the step S2 and non-condensable gas at the top of the rectification liquefying tower in a purification energy-saving device E104, removing water by molecular sieve adsorption dehydration, and removing the liquefied rectifying tower T105 after the water content is below 5 PPm; the regenerated gas adopts non-condensable gas at the top of the rectifying tower T105, the regenerated gas is heated by a regenerated gas heater E105 and then is regenerated by a water absorbing sieve, and the wet-based regenerated gas directly enters a rectifying and liquefying process without cooling to recover heat energy.
The hydrocarbon-removed conversion gas from the outlet of E103 enters a pre-filter F101A in a purification energy-saving device E104, exchanges heat with the non-condensable gas at the top of the tower from T105, reduces the temperature to 40 ℃ and enters a drying and dehydration process, and after removing condensed water, enters a dehydration tower (T104A/B) for dehydration and drying. After the dry gas from the dehydration tower passes through a post filter F101B, the moisture in the purified gas is less than or equal to 5PPm, and the gas at the outlet of F101B enters a rectification liquefaction process.
The dehydration and drying adopts a two-tower adsorption process to lead CO to 2 The moisture content in the gas reaches 5ppm of the process requirement. In order to ensure that the moisture content of the system is qualified, the dryer needs to carry out intermittent regeneration and drying, namely: one is in the adsorption drying stage, and the other is in the regeneration stage, and is periodically switched for use. The top noncondensable gas from the rectification and liquefaction process is used as the system regeneration gas, and the heating mode of the regeneration gas adopts an electric heater.
Due to CO 2 The non-condensable gas at the top of the rectifying tower T105 in the liquefaction rectifying process belongs to the downstream gas of the dried purified gas, the pressure of the non-condensable gas is lower than that of the raw gas for adsorption drying, and meanwhile, the pressure of the regenerated gas is lower than that of the raw gas because the regenerated gas needs to pass through a regenerated gas heater.
The noncondensable gas at the top of the rectifying tower T105 contains nitrogen, methane and the like, which need to be discharged out of the system and cannot be accumulated in the system, otherwise CO 2 The product does not reach the required purity, the noncondensable gas of the process reaches 220 ℃ after being heated by a regenerated gas heater E105, moisture in the molecular sieve is desorbed and taken away after passing through the molecular sieve, the heat energy of the part is taken as a heat source to a reboiler at the bottom of the T105, the regenerated gas passing through the reboiler at the bottom of the tower is cooled by an air cooler E106 and discharged at a high point, the heat energy is used as a reboiler of the T105, the cold energy of the atmosphere is utilized, and the consumption of circulating cooling water is reduced.
The step is that a pressure increasing and reducing valve is arranged on the dehydration regeneration gas system, so that the setting and energy consumption of a low-pressure regeneration gas pressurizing system are reduced; meanwhile, the regenerated gas in the step utilizes the non-condensable gas and the cold quantity of the non-condensable gas at the top of the rectifying liquefied tower, so that the consumption of raw material gas and the consumption of circulating cooling water are reduced, and the energy and the consumption are saved.
The non-condensable gas (2.15 MPaG, 27.95 ℃ below zero) from the top of the T105 is heated to 38 ℃ through E104 and then enters a regenerated gas heater E105 to be heated to 220 ℃ to be used as regenerated gas, the adsorbent of a dehydration tower (T104A/B) is regenerated, the wet base regenerated gas at the outlet of the dehydration tower (T104A/B) is 220 ℃, a regenerated gas cooler and a separator are not arranged, and the wet base regenerated gas directly enters a reboiler of a liquefaction rectification process T105 to recover heat energy.
S4: rectification and liquefaction process: cooling and precooling the product obtained in the step S3 as a heat source of a tower bottom reboiler for rectification and liquefaction, and then feeding the cooled and precooled product into a rectification tower T105 for rectification and liquefaction, wherein N is 2 Condensing and cooling the non-condensable gas components through a tower top condenser, then, recovering cold energy in the step S3 to be used as regenerated gas, wherein a tower bottom product is a qualified food-grade liquid carbon dioxide product, and decompressing and cooling liquid carbon dioxide extracted from the tower bottom through a cooler E107 to be stored in a carbon dioxide storage tank. The wet-based regenerated gas from S3 is subjected to liquefaction and rectification to recover heat, and then is subjected to high-point discharge after water is separated by a flash separator S101.
Dried CO 2 The gas enters a purifying and liquefying system, and the cooling capacity of the system is provided by a propane refrigerating unit. Dried CO from F101B 2 Firstly, entering a reboiler 1 section of the bottom of the rectifying tower T105, precooling to-12 ℃, and entering the rectifying tower T105 for low-temperature rectification after exiting the reboiler. The temperature of the non-condensable gas at the top of the tower from a built-in tower top condenser of T105 is reduced by removing E104 and the dealkylation purified gas at the outlet of E103 at the temperature of-27.95 ℃. The top gas of the rectifying tower is throttled to provide a part of cold energy for a built-in top condenser of the T105, and the other part of cold energy of the top of the rectifying tower is provided by propane. In the rectifying column, CO 2 The liquid is heated and then evaporated to obtain light components (nitrogen and methane) in the liquid, thereby obtaining the CO meeting the requirement 2 A liquid product. The liquid phase product at the bottom of the rectifying tower T105 is subjected to deep cooling by a deep cooler E107 and then is decompressed to 2.0MPa G for CO removal 2 The storage tank is used as a product storage. The 220 ℃ wet-based regenerated gas from the dehydration tower T104A/B enters a section 2 of a reboiler of T105 to recover heat and then is cooled to 120 ℃, and the cooled wet-based regenerated gas is subjected to flash evaporation in an S101 flash evaporation separator to separate water and then is cooled to 50 ℃ for high-point discharge.
The method is characterized in that the cold energy comes from cold energy provided by a propane refrigerator system, propane belongs to one of mixed refrigerants of an LNG factory, and the source of the propane can depend on a mixed refrigerant storage system of the original liquefaction factory, so that unified management and operation are facilitated.
The high-efficiency fine desulfurizing agent arranged at the lowest end of the secondary fine desulfurizing tower T103 is used for treating H generated by hydrolysis 2 S, which is to remove H 2 S active carbon desulfurizing agent, the main component is that the active carbon is added with special active agent and auxiliary agent, the specification is: phi 3-5× (3-15), bulk density: 0.60-0.70 g/ml. H 2 S content is more than or equal to 20 percent.
Compared with the prior art, the invention has the following beneficial effects:
1. LNG decarbonizing gas from a plant is converted to CO by a dealkylation conversion catalyst 2 The method comprises the steps of carrying out a first treatment on the surface of the Effectively recovering hydrocarbon substances in the tail gas and increasing 3 percent of CO 2 Is a recovery rate of (2). An oxygen supplementing system is arranged in front of the hydrocarbon removal conversion tower, and for other hydrocarbon-containing oxygen-deficient CO 2 The feed gas has a very wide range of applicability.
2. The designed pre-heater and the air cooler in front of the hydrocarbon conversion tower make full use of the energy of the atmosphere and the reaction heat of the dealkylation catalytic oxidation combustion, and have the following two technical effects:
(1) The pre-heater before the E101 tower fully utilizes the heat of the hydrocarbon catalytic oxidation reaction, heats the hydrocarbon removal raw material gas, the temperature of the hydrocarbon removal gas from R101 in the E101 is 430 ℃, the temperature is reduced to 250 ℃ after heat exchange with the desulfurization gas at 120 ℃, the heat of the hydrocarbon removal reaction is recovered, the temperature of the desulfurization gas is increased to 250 ℃ from 120 ℃, and the energy consumption 46.43% of an E102 electric heater is reduced.
(2) The tower top non-condensing pressure swing adsorption dehydration which is discharged by rectification is adopted, so that cold energy can be effectively utilized, meanwhile, linkage with an original LNG factory is reduced, stability of the device is guaranteed, the design of an air cooler is adopted for E103, and the temperature of the deoiling gas at 250 ℃ from E101 is reduced to 50 ℃ through the air cooler E103, so that the cold energy of the atmospheric environment is fully utilized, and circulating water cooling is not needed, so that the consumption of circulating water is reduced by 100%. As the catalytic oxidation combustion heat is fully utilized, 46.43 percent of traditional heating energy sources are also reduced, and the method has very important effects on energy conservation and emission reduction.
3. In the dehydration regeneration gas system, the pressure increasing and reducing valve is arranged, so that the setting and energy consumption of the low-pressure regeneration gas pressurizing system are reduced, the low-pressure regeneration gas compressor equipment necessary in the prior art is reduced, and the construction investment is reduced; compared with the traditional process of using raw material gas as regenerated gas, the invention reduces the raw material gas by 15%, and can also reduce the consumption of circulating cooling water, thereby saving energy and reducing consumption.
4. The invention adopts the recycling of the non-condensable gas at the top of the tower, and increases 9.5 percent of CO due to the reduction of the waste of the raw material gas 2 Recovery rate of the product; the energy utilization of the invention is to fully utilize the heat sources of the purified gas and the regenerated gas in the step C, thereby reducing the extra heat energy input and the tower entering temperature of the liquefaction rectification (the dehydrated purified gas is reduced from 38 ℃ to-12 ℃ and the wet-based regenerated gas is reduced from 220℃.)
The temperature is reduced to 50 ℃, so that the input of an additional cold source is reduced, if the design is not adopted, the heat energy of the first section and the second section of the reboiler needs to be additionally introduced into external heat energy, and in addition, the temperature of dehydrated raw material gas is reduced from 38 ℃ to-12 ℃ and the cold energy is required to be provided by a propane ice maker; the design of the invention fully utilizes the heat energy of the dehydrated raw material gas and the wet-based regenerated gas to provide a heat source for the T105 built-in reboiler, reduces the temperature of the raw material dry gas, reduces the cold load of a propane refrigeration system, reduces the arrangement of a pre-cooling heat exchanger in front of a tower, realizes the most economical energy recycling and reduces the energy consumption and the equipment investment.
5. The process of the invention fully captures and utilizes carbon resources in the raw material gas to prepare the food-grade liquid carbon dioxide additive, captures carbon elements and sulfur elements in the exhaust gas to prepare the food-grade liquid carbon dioxide, captures and removes the sulfur elements to reduce the emission of carbon dioxide and the pollution of sulfur elements to the environment, and is beneficial to environmental protection.
6. The technology fully utilizes cold energy, heat energy and environmental energy, reduces the energy consumption of circulating water and heating medium, has the characteristics of fully utilizing waste materials, recycling, promoting the perfection and clean production of LNG industrial chains, saving energy, reducing emission and protecting the environment.
7. The invention adopts a two-tower adsorption process, and CO 2 The tail gas of the rectifying tower of the liquefaction rectifying system belongs to the downstream gas of the dried purified gas, the pressure of the purified gas is lower than that of the raw gas for adsorption drying, and meanwhile, the pressure of the regenerated gas is lower than that of the raw gas because the regenerated gas needs to pass through a regenerated gas heater. In order to solve the control of the pressure, the process adopts a pressure release valve and a pressure boost valve, so that the traditional regenerated gas circulating booster is eliminated, and the equipment investment is reduced.
8. Compared with the prior 3.3MPa process, the invention prepares LCO 2 The rectification and liquefaction process directly rectifies, only adopts a product subcooler and a rectifying tower outside the rectifying tower, wherein a tower bottom reboiler and a tower top condenser of the rectifying tower are uniformly arranged in the tower, and the dried raw material gas and the regenerated gas directly enter a tower bottom reboiler heat exchanger to provide heat energy; the non-condensable gas at the top of the tower exchanges heat with the dry raw material gas for one time; in addition, the rectification pressure of the patent is 2.2MPa, and the method has the technical advantages of short flow, less investment and reasonable cold energy utilization.
9. According to the invention, the liquefaction and rectification process adopts propane for evaporation refrigeration, and the refrigerant adopts propane, so that the intersection with the original LNG factory is reduced, and the hidden trouble of essential linkage on system stability caused by serial-parallel connection with different systems is avoided; the direct rectification is adopted, so that the equipment investment of the cold box system and the resistance loss of the cold box system are reduced, the energy and equipment investment of the dioxide compressor are reduced, the carbon dioxide raw material gas compressor adopts two-stage compression, the outlet pressure is 2.5MPa, the energy consumption of secondary rectification liquefaction is greatly reduced, and 50% of equipment is also reduced.
10. The hydrocarbon removing process is arranged after the desulfurizing process, the COS hydrolysis temperature is 110-140, and the desulfurizing gas after the desulfurizing process directly enters the desulfurizing process without cooling, so that a desulfurizing heater and a desulfurizing cooler are not needed. The process fully utilizes compression heat to provide a heat source for desulfurization, directly utilizes compression heat at the outlet of the two-stage feed gas compressor, directly utilizes heat energy of the compressor to reduce the consumption of circulating water cooling energy, can reduce the cold energy by 32 percent according to the power analysis of the compressor under the same condition, and compared with the traditional heating process, the process does not need to add heat, so that the consumption of an external heat source is reduced by 100 percent.
11. The invention arranges a heat exchanger in front of the dealkylation tower, adopts the tower inlet raw material gas and the tower outlet dealkylation device to exchange heat, improves the temperature of the tower inlet gas, reduces the temperature of the tower outlet gas, recovers and utilizes the dealkylation reaction heat, reduces the energy consumption of an external heat source and reduces the consumption of a dealkylation gas cooling medium. The tail end of the hydrocarbon removal gas is provided with an air cooler, so that the environment cold energy is fully utilized, and the consumption of a circulating water cooling medium is reduced.
12. In the liquefaction process, two devices of a low-temperature precooler and a primary purification tower are not needed, so that the equipment is short in flow, the equipment is small in size, the occupied area is small, and pipelines, meters and valves are reduced, so that the investment is reduced, the running, the leaking and the dripping are reduced from the aspect of intrinsic safety, the control loop is reduced, and the risk of automatic control faults is reduced.
13. The invention adopts 2-tower temperature and pressure swing adsorption, utilizes the control of the pressure relief valve and the pressure increasing valve in terms of process design, and reduces the number of the switch valves by 9 compared with the prior art, thereby reducing the one-time investment of equipment, pipeline valves, occupied land and the like. The heat energy of the regenerated gas is fully recovered in the rectification and liquefaction process, and is throttled and cooled to 50 ℃ and then discharged into the atmosphere after being cooled, so that the heat energy is recovered, the ambient temperature rise around the atmosphere is reduced, and the harm of high-temperature scalding occupational diseases is essentially reduced.
14. The invention adopts a two-stage hydrolysis dry desulfurization method, directly utilizes the compression heat of the outlet of a two-stage feed gas compressor, does not need a final stage cooler and a separator of the compressor, removes COS in a purification process, and directly carries out one-step rectification in a liquefaction process, thereby reducing the equipment quantity of a liquefaction system by 50%, reducing the liquefaction load by 30%, improving the product purity, and simultaneously reducing the consumption of liquefaction cold energy and the investment of liquefaction equipment.
Drawings
FIG. 1 is a process flow diagram of the present invention
Figure number and name: c101: a feed gas compressor; e101: inlet and outlet tower heat exchangers; e102, a hydrocarbon removal heater; e103, a hydrocarbon removal air cooler; e104, purifying gas energy-saving device; e105, a regeneration gas heater; e107, a subcooler; F101A, a pre-filter; F101B, a post filter; t101: a fine desulfurization tower; t102: a first-stage fine desulfurization tower; t103: a second-stage fine desulfurization tower; t105 is a rectifying tower; T104B: a drying tower B; T104A is a drying tower A; P101A is a carbon dioxide pump A; P101B is a carbon dioxide pump B; s101, a flash separator; r101 is a dealkylation reaction tower; x101: propane cycle ice machine.
Detailed Description
The present invention will now be described in detail with reference to the drawings and the specific embodiments thereof, wherein the illustrative embodiments and descriptions of the invention are for illustration, but not for limitation.
In the description of the present invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate description of the present invention and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.
Example 1
As shown in fig. 1, the process for preparing food-grade liquid carbon dioxide by using decarbonized exhaust gas of an LNG plant according to the present invention comprises the following steps:
s1: desulfurization procedure: the decarbonized LNG decarbonized exhaust gas is compressed by a two-stage compressor C101, the outlet of the first-stage compressor directly enters a fine desulfurization tower T101 to remove inorganic sulfur, and the desulfurized gas enters the two-stage compressor. The gas at the outlet of the second-stage compressor directly enters the second-stage medium-temperature hydrolysis desulfurization system without heat exchange, is subjected to hydrolysis and zinc oxide desulfurization sequentially through a first-stage fine desulfurization tower T102 and a second-stage fine desulfurization tower T103, and a high-efficiency fine desulfurizing agent is arranged at the bottommost end of the second-stage fine desulfurization tower T103, so that the total sulfur content in the finally desulfurized gas is 0.1PPm. The raw material gas is captured and stored in the desulfurizing agent under the action of the desulfurizing agent, so that the pollution to the environment is reduced.
S2: a hydrocarbon removal conversion step: the product obtained in the step S1 contains C1-C4 and directly enters into a tower heat exchanger E101 and a hydrocarbon removal heater E102 without cooling, the product obtained in the step S1 is converted into CO2 under the action of a hydrocarbon removal conversion catalyst, and the hydrocarbon removal gas from the hydrocarbon removal reactor R101 is cooled by the tower heat exchanger E101 and an air cooler E103.
S3, dehydration and drying steps: cooling the product obtained in the step S2 and non-condensable gas at the top of the rectification liquefying tower in a purification energy-saving device E104, removing water by molecular sieve adsorption dehydration, and removing the liquefied rectifying tower T105 after the water content is below 5 PPm; the regenerated gas adopts non-condensable gas at the top of the rectifying tower T105, the regenerated gas is heated by a regenerated gas heater E105 and then is regenerated by a water absorbing sieve, and the wet-based regenerated gas directly enters a rectifying and liquefying process without cooling to recover heat energy.
S4: rectification and liquefaction process: and (3) cooling and precooling the product obtained in the step (S3) as a heat source of a tower bottom reboiler for rectification and liquefaction, then enabling the product to enter a rectification tower T105 for rectification and liquefaction, condensing and cooling non-condensable gas components such as N2 and the like through a tower top condenser, recycling cold energy in the step (S3) and then using the recovered cold energy as regenerated gas, wherein the tower bottom product is a qualified food-grade liquid carbon dioxide product, and decompressing and cooling liquid carbon dioxide extracted from the tower bottom through a cooler E107 and then storing the liquid carbon dioxide in a carbon dioxide storage tank. The wet-based regenerated gas from S3 is subjected to liquefaction and rectification to recover heat, and then is subjected to high-point discharge after water is separated by a flash separator S101.
The S1 step is the initial inorganic sulfur H 2 The fine desulfurization tower T101 of the S is arranged at a section of outlet of the feed gas compressor C101; the organic sulfur such as COS adopts a secondary hydrolysis serial removal process, a secondary compressor outlet of a feed gas compressor C101 is not provided with a cooler and a separator, and directly enters a primary fine desulfurization tower T102, the primary fine desulfurization tower T102 and a secondary fine desulfurization tower T103 are directly provided with a hydrolysis fine desulfurizing agent at the upper part, and an inorganic sulfur fine desulfurizing agent is arranged at the lower part, so that secondary hydrolysis desulfurization is implemented.
The refined desulfurization gas generated in the step S1 directly enters the step S2 without passing through a desulfurization gas cooling heat exchanger; e101 in-out tower heat exchangers are arranged at the rear end of a dealkylation reaction tower R101, heat exchange is carried out on in-out tower gas, the load of a dealkylation heater E102 is reduced, and E103 is a dealkylation gas air cooler; the catalytic oxidation dealkylation is provided with a standby oxygen supplementing system.
The step S3 is to adopt a 2-tower pressure swing adsorption dehydration process; the non-condensable gas in the step S4 is adopted as the regenerated gas in the dehydration process, a purified gas energy-saving device E104 is arranged, the non-condensable gas cold energy of a rectifying tower T105 is utilized, a regenerated gas cooler and a separator are not arranged in the wet-based regenerated gas, and the wet-based regenerated gas is directly subjected to rectification and liquefaction to recover heat energy.
The cold energy of the step S4 is from cold energy provided by a propane refrigerator system, the cold energy of the non-condensable gas at the top of the tower is recovered in the step S3, and the heat energy of the purified gas and the wet-base regenerated gas in the step S3 is recovered.
The high-efficiency fine desulfurizing agent arranged at the lowest end of the secondary fine desulfurizing tower T103 is used for removing H 2 S active carbon desulfurizing agent, the main ingredients include active carbon additive active agent, auxiliary agent, specification: phi 3-5× (3-15), bulk density: 0.60-0.70 g/ml, H2S content is more than or equal to 20%.
The raw material gas (LNG decarburization effluent gas of a factory) is CO with the boundary pressure of 0.01-0.03 MPa (G) and the temperature of 45 DEG C 2 Raw material gas enters a first-stage buffer tank at the inlet of a carbon dioxide raw material gas compressor C101 and passes through CO 2 After the primary compression of the compressor and the boosting to 0.8-0.9 MPaG, the compressed gas sequentially passes through a first-stage cooler (an air cooler or a circulating water cooler, specifically determined according to meteorological data of the site), a first-stage separator, the temperature is 40 ℃ after cooling, cooling and separating, compressed gas from the outlet of the first-stage separator of a raw gas compressor C101 enters a refined desulfurization tower T101, and inorganic sulfur H is removed by an active carbon desulfurizing agent of the refined desulfurization tower T101 2 S, H in desulfurization gas at outlet of refined desulfurization tower T101 2 S concentration is less than or equal to 0.1PPm, and H is removed 2 The raw material gas of S continuously returns to the raw material gas compressor C101 for compression; the outlet gas of the refined desulfurization tower T101 enters the inlet of the second-stage compressor of the raw material gas compressor C101, is pressurized to 2.5MPaG through the second-stage compressor of the raw material gas compressor C101, and enters the secondary hydrolysis refined desulfurization system for desulfurization at 120-140 ℃.
The gas from the second-stage outlet of the feed gas compressor C101 firstly enters a first-stage fine desulfurization tower T102 for carrying out first-stage hydrolysis desulfurization, the upper part of the first-stage fine desulfurization tower T102 is provided with a hydrolysis fine desulfurizing agent, the lower part of the first-stage fine desulfurization tower T102 is provided with a zinc oxide fine desulfurizing agent, the gas from the bottom of the first-stage fine desulfurization tower T102 enters a second-stage fine desulfurization tower T103 from the top of the second-stage fine desulfurization tower T103 for carrying out second-stage hydrolysis fine desulfurization, the upper part of the second-stage fine desulfurization tower T103 is provided with a hydrolysis fine desulfurizing agent, the middle part of the second-stage fine desulfurization tower T103 is provided with a zinc oxide fine desulfurizing agent, and the bottom of the second-stage fine desulfurization tower T103 is provided with a high-efficiency fine desulfurizing agent, so that the total sulfur content in the gas subjected to the second-stage hydrolysis fine desulfurization is 0.1PPm.
The desulphurized gas from the second-stage fine desulphurized tower T103 is 110-130 ℃, the pressure is 2.4MPaG, the desulphurized gas enters a heat exchanger E101 of an inlet tower and outlet tower and is heated by heat exchange with the outlet gas (430 ℃ and 2.3 MPaG) of a dealkylation reaction tower R101, the desulphurized gas enters an electric heater of a dealkylation heater E102 to be heated to 400 ℃, and then enters the dealkylation reaction tower R101 and C in raw gas 1 ～C 4 Alkane is subjected to catalytic oxidation reaction under the action of noble metal catalyst to generate CO 2 And H 2 O. C in the raw material gas after reaction 1 ～C 4 The alkane content is less than 1ppm. The dehydrogenation gas enters a dealkylation gas air cooler E103 after entering and exiting a tower heat exchanger E101, and is cooled to 50-60 ℃ by using the cold energy of the ambient air, and then goes to a downstream dehydration and drying process.
And S2, introducing the product obtained in the step S2 into a purification energy-saving device E104 from the hydrocarbon removal conversion gas at the outlet of a hydrocarbon removal gas air cooler E103, exchanging heat with non-condensable gas at the top of a rectifying tower T105 to reduce the temperature to 40 ℃, introducing into a pre-filter F101A in a drying and dehydrating process, removing condensed water, and introducing into a drying tower (T104A/B) for dehydration and drying. After the dry gas from the dehydration tower passes through the post filter F101B, the moisture in the purified gas is less than or equal to 5PPm, and the gas at the outlet of the post filter F101B enters the rectification liquefaction process.
The non-condensable gas (2.15 MPaG, 27.95 ℃ below zero) from the top of the rectifying tower T105 is heated to 38 ℃ through a purified gas energy-saving device E104, then enters a regenerated gas heater E105 to be heated to 220 ℃ to be used as regenerated gas, the adsorbent of the drying tower (T104A/B) is regenerated, the wet-base regenerated gas at the outlet of the drying tower (T104A/B) is 220 ℃, a regenerated gas cooler and a separator are not arranged, and the wet-base regenerated gas directly enters a rectifying tower T105 reboiler for recovering heat energy in the liquefaction rectifying process.
Dried CO 2 The gas enters a purifying and liquefying system, and the cooling capacity of the system is provided by a propane refrigerating unit; from post-filterDried CO of F101B 2 Firstly, entering a 1 section of a reboiler at the bottom of a rectifying tower T105, precooling to-12 ℃, and entering the rectifying tower T105 for low-temperature rectification after exiting the reboiler; the temperature of the non-condensable gas at the top of the tower from a condenser arranged in the top of the rectifying tower T105 is reduced by the dealkylation purifying gas energy economizer E104 at the temperature of-27.95 ℃ and the dealkylation purifying gas at the outlet of the dealkylation gas air cooler E103; the top gas of the rectifying tower is throttled to provide a part of cold energy for a condenser arranged in the rectifying tower T105 at the top of the rectifying tower, and the other part of cold energy at the top of the rectifying tower is provided by propane; in the rectifying column, CO 2 The liquid is heated and then evaporated to obtain light components (nitrogen and methane) in the liquid, thereby obtaining the CO meeting the requirement 2 A liquid product. The liquid phase product at the bottom of the rectifying tower T105 is subjected to deep cooling by a cooler E107 and then is decompressed to 2.0MPa.G for CO removal 2 The storage tank is used for storing products; the 220 ℃ wet-based regenerated gas from the drying tower T104A/B enters a reboiler 2 section of the rectifying tower T105 to recover heat and then is cooled to 120 ℃, the cooled wet-based regenerated gas is subjected to flash evaporation in a flash evaporation separator S101, water is subjected to flash evaporation separation, and then the temperature is reduced to 50 ℃ and the high-point discharge is carried out.
The method is characterized in that the cold energy comes from providing cold energy with a propane refrigerator system, propane belongs to one of mixed refrigerants of an LNG factory, and the source of the propane can depend on a mixed refrigerant storage system of the original liquefaction factory, so that unified management and transportation are facilitated.
The high-efficiency refined desulfurizing agent arranged at the lowest end of the secondary refined desulfurizing tower T103 is used for treating H2S generated by hydrolysis, belongs to an active carbon refined desulfurizing agent for removing the H2S, and mainly comprises the following components of adding special active agents and auxiliary agents into active carbon, and has the specification: phi 3-5× (3-15), bulk density: 0.60-0.70 g/ml. H2S content is more than or equal to 20 percent.
The four technical processes of the invention solve the problems of more equipment, more occupied land and increased investment in the prior art; because the equipment is reduced, the installation process is relatively simple, the production process flow is greatly shortened, the resources can be fully utilized, the resource waste is reduced, the energy conservation and emission reduction are more environment-friendly, and the hidden trouble of causing injury to personnel and equipment is avoided.
The foregoing has outlined the detailed description of the embodiments of the present invention, and the detailed description of the embodiments and the embodiments of the present invention has been provided herein by way of illustration of specific examples, which are intended to be merely illustrative of the principles of the embodiments of the present invention.
Claims (6)
1. The process for preparing food-grade liquid carbon dioxide by utilizing the decarburization exhaust gas of the LNG factory is characterized by comprising the following steps of:
s1: desulfurization procedure: the decarbonized LNG decarbonized exhaust gas is compressed by a two-stage compressor C101, the outlet of the first-stage compressor directly enters a fine desulfurization tower T101 to remove inorganic sulfur, desulfurized gas enters the second-stage compressor, the outlet gas of the second-stage compressor directly enters a second-stage medium-temperature hydrolysis desulfurization system without heat exchange, hydrolysis and zinc oxide desulfurization are carried out by sequentially passing through a first-stage fine desulfurization tower T102 and a second-stage fine desulfurization tower T103, a high-efficiency fine desulfurization agent is arranged at the bottommost end of the second-stage fine desulfurization tower T103, the total sulfur content in the finally desulfurized gas is 0.1PPm, and raw gas is trapped and stored in the desulfurizing agent under the effect of the desulfurizing agent, so that the pollution to the environment is reduced;
s2: a hydrocarbon removal conversion step: the product obtained in the step S1 contains C1-C4 and directly enters a heat exchanger E101 of an inlet tower and a heat exchanger E102 of a hydrocarbon removal heater without cooling, the product obtained in the step S1 is converted into CO2 under the action of a hydrocarbon removal conversion catalyst, and the temperature of hydrocarbon removal gas from the hydrocarbon removal reactor R101 is reduced through the heat exchanger E101 of the inlet tower and the heat exchanger E103 of the outlet tower and an air cooler E103;
s3, dehydration and drying steps: cooling the product obtained in the step S2 and non-condensable gas at the top of the rectification liquefying tower in a purification energy-saving device E104, removing water by molecular sieve adsorption dehydration, and removing the liquefied rectifying tower T105 after the water content is below 5 PPm; the regenerated gas adopts non-condensable gas at the top of a rectifying tower T105, the regenerated gas is heated by a regenerated gas heater E105 and then is regenerated by a water absorbing sieve, and wet-based regenerated gas directly enters a rectifying and liquefying process without cooling to recover heat energy;
s4: rectification and liquefaction process: the product obtained in the step S3 is used as a heat source of a tower bottom reboiler for rectification liquefaction to cool and precool, and then enters a rectifying tower T105 for rectification liquefaction, non-condensable gas components such as N2 and the like are condensed and cooled by a tower top condenser, the product is used as regenerated gas after cold energy is recovered in the step S3, the tower bottom product is a qualified food-grade liquid carbon dioxide product, the liquid carbon dioxide extracted from the tower bottom is decompressed and cooled by a cooler E107 and then is stored in a carbon dioxide storage tank, and the wet-based regenerated gas from the step S3 is subjected to high-point discharge after heat is recovered by the liquefaction rectification and is separated by a flash separator S101.
2. The process for producing food grade liquid carbon dioxide from LNG plant decarbonized effluent gas of claim 1, wherein: the S1 step is the initial inorganic sulfur H 2 The fine desulfurization tower T101 of the S is arranged at a section of outlet of the feed gas compressor C101; the organic sulfur such as COS adopts a secondary hydrolysis serial removal process, a secondary compressor outlet of a feed gas compressor C101 is not provided with a cooler and a separator, and directly enters a primary fine desulfurization tower T102, the primary fine desulfurization tower T102 and a secondary fine desulfurization tower T103 are directly provided with a hydrolysis fine desulfurizing agent at the upper part, and an inorganic sulfur fine desulfurizing agent is arranged at the lower part, so that secondary hydrolysis desulfurization is implemented.
3. The process for producing food grade liquid carbon dioxide from LNG plant decarbonized effluent gas of claim 2, wherein: the refined desulfurization gas generated in the step S1 directly enters the step S2 without passing through a desulfurization gas cooling heat exchanger; e101 in-out tower heat exchangers are arranged at the rear end of a dealkylation reaction tower R101, heat exchange is carried out on in-out tower gas, the load of a dealkylation heater E102 is reduced, and E103 is a dealkylation gas air cooler; the catalytic oxidation dealkylation is provided with a standby oxygen supplementing system.
4. A process for producing food grade liquid carbon dioxide from LNG plant decarbonized effluent gas as claimed in claim 3, wherein: the step S3 is to adopt a 2-tower pressure swing adsorption dehydration process; the non-condensable gas in the step S4 is adopted as the regenerated gas in the dehydration process, a purified gas energy-saving device E104 is arranged, the non-condensable gas cold energy of a rectifying tower T105 is utilized, a regenerated gas cooler and a separator are not arranged in the wet-based regenerated gas, and the wet-based regenerated gas is directly subjected to rectification and liquefaction to recover heat energy.
5. The process for producing food grade liquid carbon dioxide from LNG plant decarbonized effluent gas of claim 4, wherein: the cold energy of the step S4 is from cold energy provided by a propane refrigerator system, the cold energy of the non-condensable gas at the top of the tower is recovered in the step S3, and the heat energy of the purified gas and the wet-base regenerated gas in the step S3 is recovered.
6. The process for producing food grade liquid carbon dioxide from LNG plant decarbonized effluent gas of claim 5, wherein: the high-efficiency fine desulfurizing agent arranged at the lowest end of the secondary fine desulfurizing tower T103 is used for removing H 2 S active carbon desulfurizing agent, the main ingredients include active carbon additive active agent, auxiliary agent, specification: phi 3-5× (3-15), bulk density: 0.60-0.70 g/ml, H2S content is more than or equal to 20%.
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| CN117704745A (en) * | 2023-12-05 | 2024-03-15 | 南京佳华科技股份有限公司 | Efficient energy-saving preparation of food-grade CO 2 Method and system of (2) |
| CN117704745B (en) * | 2023-12-05 | 2024-05-24 | 南京佳华科技股份有限公司 | Efficient energy-saving preparation of food-grade CO2Method and system of (2) |
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