CN114963691B - Low pressure CO 2 Gas low-temperature separation method and device - Google Patents
Low pressure CO 2 Gas low-temperature separation method and device Download PDFInfo
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- CN114963691B CN114963691B CN202210610116.1A CN202210610116A CN114963691B CN 114963691 B CN114963691 B CN 114963691B CN 202210610116 A CN202210610116 A CN 202210610116A CN 114963691 B CN114963691 B CN 114963691B
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- 238000000926 separation method Methods 0.000 title claims abstract description 30
- 239000007789 gas Substances 0.000 claims abstract description 165
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 43
- 239000002994 raw material Substances 0.000 claims abstract description 33
- 238000000746 purification Methods 0.000 claims abstract description 18
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 17
- 238000011084 recovery Methods 0.000 claims abstract description 17
- 238000001816 cooling Methods 0.000 claims abstract description 12
- 238000000034 method Methods 0.000 claims abstract description 8
- 230000006835 compression Effects 0.000 claims abstract description 7
- 238000007906 compression Methods 0.000 claims abstract description 7
- 238000004064 recycling Methods 0.000 claims abstract description 6
- 239000002918 waste heat Substances 0.000 claims abstract description 4
- 239000007788 liquid Substances 0.000 claims description 12
- 239000007791 liquid phase Substances 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 239000012071 phase Substances 0.000 claims description 7
- 239000002737 fuel gas Substances 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 5
- IGEZMQWPBDNNPS-UHFFFAOYSA-N B.CO Chemical compound B.CO IGEZMQWPBDNNPS-UHFFFAOYSA-N 0.000 claims description 3
- 239000004215 Carbon black (E152) Substances 0.000 claims description 3
- 239000000446 fuel Substances 0.000 claims description 3
- 229930195733 hydrocarbon Natural products 0.000 claims description 3
- 150000002430 hydrocarbons Chemical class 0.000 claims description 3
- 239000007792 gaseous phase Substances 0.000 claims description 2
- 238000005265 energy consumption Methods 0.000 abstract description 11
- 238000010992 reflux Methods 0.000 abstract description 4
- 238000009833 condensation Methods 0.000 abstract description 3
- 230000005494 condensation Effects 0.000 abstract description 3
- 238000005516 engineering process Methods 0.000 description 7
- 239000002803 fossil fuel Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 125000004122 cyclic group Chemical group 0.000 description 2
- 206010015137 Eructation Diseases 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000009919 sequestration Effects 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
- 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
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/50—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
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/02—Processes or apparatus using separation by rectification in a single pressure main column system
-
- 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
-
- 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
- F25J2210/00—Processes characterised by the type or other details of the feed stream
- F25J2210/04—Mixing or blending of fluids with 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
- F25J2210/00—Processes characterised by the type or other details of the feed stream
- F25J2210/70—Flue or combustion exhaust gas
-
- 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
-
- 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
- F25J2215/80—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
- 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
-
- 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
- F25J2245/00—Processes or apparatus involving steps for recycling of process streams
- F25J2245/02—Recycle of a stream in general, e.g. a by-pass 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
- F25J2270/90—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02C20/00—Capture or disposal of greenhouse gases
- Y02C20/40—Capture or disposal of greenhouse gases of CO2
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Separation By Low-Temperature Treatments (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
The invention relates to low-pressure CO 2 Gas low-temperature separation method and device, pressurizing raw gas, utilizing waste heat and utilizing CO 2 Initial cooling down, CO 2 The method comprises the steps of deep condensation liquefaction, product separation and purification, tower top gas recycling, and comprises a raw material gas compressor and CO 2 According to the scheme, the raw material gas pressurization is completed through primary compression, the cold energy required by the tower top gas throttling condenser is provided by a medium, so that the energy consumption is reduced, the use of ammonia is reduced, and the CO 2 The initial cooler adopts a three-flow plate-fin heat exchanger, a heat exchange network is optimized, the heat exchange efficiency is improved, the purification adopts a stripping tower, the top reflux is canceled, the automatic control system of the tower is simplified, the built-in plate-fin heat exchanger is used as a tower bottom reboiler, and the CO is realized by using a raw gas compressor 2 The recycling of the tower top gas improves the equipment utilization rate and CO 2 Is a recovery rate of (2).
Description
Technical Field
The invention relates to a gas separation technology, in particular to a low-pressure CO 2 A low-temperature gas separation method and a device.
Background
CO in the atmosphere 2 The concentration rise has profound effects on human society and natural environment, and a plurality of major disasters are closely related to the concentration rise, so that CO is reduced 2 Is a problem related to the sustainable development of human society and is therefore receiving a great deal of attention from countries around the world.
And CO 2 The emissions of fossil fuels are mainly from the combustion of fossil fuels, and the global fossil fuel-based energy structure is not fundamentally changed recently due to various factors, and carbon capture utilization and sequestration technology (CCUS) is to reduce the emission of atmospheric CO without reducing the current fossil fuel usage 2 Means for measuring the amount of gas. The technology is one of the emission reduction technologies which are particularly heavy in the world clean energy leading position and actively cope with climate change in developed countries such as English, american, japanese and the like at present. The technology is also determined to be a key emission reduction technology in China. Currently related CCUS engineering has not yet achieved commercial application. The carbon capture project has high cost and high energy consumption, and is difficult to generate economic benefit, thus becoming a root cause for restricting the development of the carbon capture project. Thus for the CO with the most industrial application prospect 2 The low-temperature separation process and the device have important significance in energy-saving optimization research.
In recent years, although research on the process has resulted in a certain result, there are certain disadvantages, or CO 2 The recovery rate is low, and the energy consumption of unit product is higher; or the process flow is complex, and the number of the equipment is large; or more ammonia use points, increased leakage risk and higher potential safety hazard.
In summary, the existing technology and device cannot achieve the low energy consumption, high yield, simple flow and high safety.
Disclosure of Invention
Accordingly, the primary object of the present invention is to provide a low pressure CO 2 According to the technical scheme, the pressurization of the raw material gas is completed through primary compression, the cooling capacity required by the condensation of the tower top gas and the heat required by the system are provided by the medium, so that the energy consumption is reduced, the use of ammonia is reduced, and the CO is obtained 2 Initial coolingThe device adopts a plate-fin heat exchanger, optimizes a heat exchange network, improves heat exchange efficiency, adopts a stripping tower for product purification, eliminates top reflux, simplifies an automatic control system of the tower, and adopts a built-in plate-fin heat exchanger as a tower bottom reboiler. CO is realized by using a raw material gas compressor 2 The recycling of the tower top gas improves the equipment utilization rate and CO 2 Is of CO 2 The recovery rate can be improved by more than 12 percent.
The invention provides a low-pressure CO 2 A method for the cryogenic separation of a gas comprising the steps of:
A. pressurizing raw material gas and utilizing waste heat: CO meeting the water content requirement 2 The raw material gas is pressurized to 2.5MPa-4.0MPa by a raw material gas compressor at the temperature of 5-40 ℃ and the pressure of 70-85 ℃ under the pressure of 0.2-1.0 MPa; then enters a tower bottom reboiler to provide heat for the purification system, and the temperature of the raw material gas is reduced to 21.6-35.5 ℃;
B.CO 2 initial cooling and cooling: the raw material gas obtained in the step A and coming out from the reboiler at the bottom of the tower enters CO 2 The initial cooler exchanges heat with two cold streams from the overhead gas throttling condenser and the overhead gas separator and is initially cooled to 12.3-25.5 ℃;
C.CO 2 deep condensing and liquefying: the raw gas after initial cooling enters CO 2 The deep condensing liquefier is further cooled to the temperature of minus 10 ℃ to minus 20 ℃ to condense more than 85 percent of raw material gas into liquid, CO 2 The cold energy required by the deep condensing liquefier is provided by an ammonia refrigerator group through liquid ammonia circulation, and CO is cooled 2 Returning the formed gas ammonia to the ammonia refrigerator group;
D. and (3) product separation and purification: c, deep condensing and liquefying the CO 2 Enters a stripping tower for separation and purification, and CO is obtained after purification 2 Liquid CO with purity of more than 99% 2 A product;
E. and (3) recycling tower top gas: the stripping tower top gas is cooled to minus 32 ℃ through a tower top gas throttling condenser, and then enters a tower top gas separator, and CO in the separated liquid phase 2 The content can reach 92%, then the temperature is reduced to minus 62 ℃, and the mixture enters a tower top gas throttling condenser to exchange heat with the stripping tower top gasRaising the temperature to-31 ℃ and then entering CO 2 The initial cooler exchanges heat with the raw gas obtained in the step A and coming out of the reboiler at the bottom of the tower to further recover cold energy, then the temperature is raised to 15-25 ℃, and the raw gas enters a raw gas compressor to be mixed with the raw gas and then enters a subsequent flow path, so that the CO is improved 2 Is a recovery rate of (2); the gaseous phase of the overhead separator contains CO 2 About 45 percent of hydrocarbon gas 55 percent is throttled, depressurized and cooled to about 65 ℃ below zero and enters CO 2 The temperature of the initial cooler is raised to 15-25 ℃ after cold energy recovery, and the initial cooler enters an in-station fuel system to realize the recovery and reutilization of fuel gas resources.
As a further technical proposal, the feed gas of the feeding device in the step A requires CO 2 The content is as follows>75% water content<200ppm。
As a further technical scheme, the raw material gas pressurization in the step A adopts primary compression.
The invention provides a low-pressure CO 2 The low-temperature gas separating device comprises a raw gas compressor and CO 2 Initial cooler and tower reboiler, and feeding device CO meeting water content requirement 2 The feed gas enters the input end of a feed gas compressor, the output end of the feed gas compressor is connected with the input end of a tower bottom reboiler, and the output end of the tower bottom reboiler is connected with liquid CO 2 The outer conveying pipeline is connected.
As a further technical proposal, the method also comprises CO 2 The deep condensing liquefier and the stripping tower are arranged at the bottom in the stripping tower, and the output end of the tower bottom reboiler passes through CO 2 Initial cooler post-CO 2 The input end of the deep condensing liquefier is connected with CO 2 The output end of the deep condensing liquefier is connected with the input end of the stripping tower, and the liquid phase output end of the stripping tower is connected with liquid CO 2 The outer conveying pipeline is connected.
As a further technical scheme, the device also comprises a tower top gas throttling condenser and a tower top gas separator, wherein the gas phase output end of the stripping tower is connected with the shell side input end of the tower top gas throttling condenser, the shell side output end of the tower top gas throttling condenser is connected with the input end of the tower top gas separator, the liquid phase output end of the tower top gas separator is connected with the tube side input end of the tower top gas throttling condenser, and the tube side of the tower top gas throttling condenserThe output end is through CO 2 The initial cooler is connected with the input end of a raw material gas compressor, and the gas phase output end of the tower top gas separator passes through CO 2 The initial cooler is connected to the fuel gas system.
As a further technical scheme, the feed gas compressor is a screw compressor;
as a further technical scheme, the CO 2 The initial cooler is a three-flow plate-fin heat exchanger.
As a further technical scheme, the tower bottom reboiler is a built-in plate-fin heat exchanger.
As a further technical scheme, the CO 2 Liquid ammonia inlet and CO of deep condensing liquefier 2 The ammonia outlet of the deep condensing liquefier is respectively connected with a liquid ammonia circulating pipeline of the refrigerating unit.
The beneficial effects after adopting above-mentioned technical scheme are: low-pressure CO 2 According to the technical scheme, the pressurization of the raw material gas is completed through primary compression, the cooling capacity required by the condensation of the tower top gas and the heat required by the system are provided by the medium, so that the energy consumption is reduced, the use of ammonia is reduced, and the CO is obtained 2 The initial cooler adopts a plate-fin heat exchanger, so that a heat exchange network is optimized, the heat exchange efficiency is improved, a stripping tower is adopted for product purification, the reflux of the tower top is canceled, an automatic control system of the tower is simplified, the built-in plate-fin heat exchanger is adopted as a tower bottom reboiler, the occupied space is reduced, and the heat exchange effect is improved. CO is realized by using a raw material gas compressor 2 The cyclic utilization of the tower top gas omits the arrangement of a tower top gas compressor, and improves the equipment utilization rate and CO 2 Is of CO 2 The recovery rate can be improved by more than 12 percent.
Drawings
Fig. 1 is a schematic diagram of the overall connection structure of the present invention.
In the figure, a 1-raw material gas compressor, a 2-tower bottom reboiler and 3-CO 2 Initial cooler, 4-CO 2 The device comprises a deep condensing liquefier, a 5-stripping tower, a 6-tower top gas throttling condenser, a 7-tower top gas separator and an 8-liquid ammonia circulating pipeline.
Detailed Description
Specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
As shown in fig. 1, the low pressure CO according to the present invention 2 A method for the cryogenic separation of a gas comprising the steps of:
A. pressurizing raw material gas and utilizing waste heat: CO meeting the water content requirement 2 The raw material gas is pressurized to 3.5MPa by a raw material gas compressor 1 at the temperature of 80 ℃ under the pressure of 0.2MPa to 1.0MPa and the temperature of 5 ℃ to 40 ℃; then heat is provided for the purification system through a tower bottom reboiler 2, and the temperature of the raw material is reduced to 30 ℃;
B.CO 2 initial cooling and cooling: the raw material gas obtained in the step A and coming out from the reboiler at the bottom of the tower enters CO 2 The initial cooler 3 exchanges heat with two cold streams from the overhead gas throttling condenser 6 and the overhead gas separator 7 and is initially cooled to 12.3-25.5 ℃;
C.CO 2 deep condensing and liquefying: the raw gas after initial cooling enters CO 2 The deep condensing liquefier 4 is further cooled to the temperature of minus 10 ℃ to condense more than 85 percent of raw material gas into liquid, CO 2 The cold energy required by the deep condensing liquefier 4 is provided by an ammonia refrigerator group through liquid ammonia circulation, and CO is cooled 2 Returning the formed gas ammonia to the ammonia refrigerator group;
D. and (3) product separation and purification: c, deep condensing and liquefying the CO 2 Enters a stripping tower 5 for separation and purification, and CO is obtained after purification 2 Liquid CO with purity of more than 99% 2 A product;
E. and (3) recycling tower top gas: the top gas of the stripping tower 5 is firstly cooled to the temperature of minus 32 ℃ by a top gas throttling condenser and then enters a top gas separator 7, and CO in the separated liquid phase 2 The content can reach 92%, then the temperature is reduced to minus 62 ℃, then the mixture enters the tower top gas throttling condenser 6 to exchange heat with the stripping tower top gas, the temperature is increased to minus 31 ℃, and then the mixture enters CO 2 The initial cooler 3 exchanges heat with the raw gas obtained in the step A and coming out of the tower bottom reboiler 2 to further recover cold energy, then the temperature is raised to 15-25 ℃, and the raw gas enters into the raw gas compressor 1 to be mixed with the raw gas and then enters into the subsequent process, so that the CO is improved 2 Is a recovery rate of (2); gas of the tower top gas separator 7The phase containing CO 2 About 45 percent of hydrocarbon gas 55 percent is throttled, depressurized and cooled to about 65 ℃ below zero and enters CO 2 The temperature of the initial cooler 3 is raised to 15-25 ℃ after cold recovery, and the initial cooler enters an in-station fuel system to realize the recovery and reutilization of fuel gas resources.
As a further example, the feed gas to the apparatus in step A requires CO 2 The content is as follows>75% water content<200ppm。
As a further example, the step A is a step A of pressurizing the feed gas by first-stage compression;
the invention relates to low-pressure CO 2 The gas low-temperature separation device comprises a raw gas compressor 1 and CO 2 An initial cooler 3 and a tower bottom reboiler 2, and a feeding device CO meeting the water content requirement 2 The feed gas is connected with the input end of a feed gas compressor 1, the output end of the feed gas compressor 1 is connected with the input end of a tower bottom reboiler 2, and the output end of the tower bottom reboiler 2 is connected with liquid CO 2 The outer conveying pipeline is connected.
As a further embodiment, also includes CO 2 The deep condensing liquefier 4 and the stripping tower 5, the tower bottom reboiler 2 is arranged at the inner bottom of the stripping tower 5, and the output end of the tower bottom reboiler 2 passes through CO 2 Initial cooler 3 post-CO 2 The input end of the deep condensing liquefier 4 is connected with CO 2 The output end of the deep condensing liquefier 4 is connected with the input end of the stripping tower 5, and the liquid phase output end of the stripping tower 5 is connected with liquid CO 2 The outer conveying pipeline is connected.
As a further example, the device also comprises a tower top air throttle condenser 6 and a tower top air separator 7, wherein the gas phase output end of the stripping tower 5 is connected with the shell side input end of the tower top air throttle condenser 6, the shell side output end of the tower top gas throttling condenser 6 is connected with the input end of the tower top gas separator 7, the liquid phase output end of the tower top gas separator 7 is connected with the tube side input end of the tower top gas throttling condenser 6, and the tube side output end of the tower top gas throttling condenser 6 passes through CO 2 The initial cooler 3 is connected with the input end of the feed gas compressor 1, and the gas phase output end of the tower top gas separator 7 passes through CO 2 The initial cooler 3 is connected to the fuel gas system.
As a further example, the feed gas compressor 1 is a screw compressor;
as a further example, the CO 2 The initial cooler 3 is a three-flow plate-fin heat exchanger.
As a further example, the bottom reboiler 2 is a built-in plate-fin heat exchanger.
As a further example, the CO 2 Liquid ammonia inlet and CO of deep condensing liquefier 4 2 The gas ammonia outlet of the deep condensing liquefier 4 is respectively connected with a liquid ammonia circulating pipeline 8 of the refrigerating unit.
Application of the low pressure CO of the invention in the above examples 2 Technical scheme of gas low-temperature separation method and device, in particular to low-pressure gas and CO aiming at raw material gas 2 The content is as follows>75% of the scenes.
1) The pressurization of the raw material gas compressor 1 is completed through primary compression, so that the equipment composition is simplified;
2) The heat used for separating and purifying the part and the cold required by the tower top gas throttling condenser 6 are provided by the medium, so that the energy consumption is reduced, the use and the distribution of ammonia are reduced, and the safety of the device is greatly improved;
3)CO 2 the initial cooler 3 adopts a three-flow plate-fin heat exchanger, so that a heat exchange network is optimized, and the heat exchange efficiency is improved;
4) The reboiler 2 at the bottom of the tower is arranged at the inner bottom of the stripping tower 5 by adopting a built-in plate-fin heat exchanger, so that the occupied space is reduced, and the heat exchange effect is improved;
5) The separation and purification cancel the top reflux, and reduce the complexity of the control system;
6) CO is realized by using the raw material gas compressor 1 2 The cyclic utilization of the tower top gas omits the arrangement of a tower top gas compressor, and improves the equipment utilization rate and CO 2 Is a recovery rate of (2).
According to the technical scheme, detection data in practical application are as follows:
| project | Quantity and name |
| CO 2 Recovery amount | 5783kg/h |
| CO 2 Recovery rate | 92.51％ |
| CO 2 Purity of the product | 99% or more |
| Energy consumption of supercharging part | 0.218MJ/kg.CO 2 |
| Separation of liquefied fraction energy consumption | 0.179MJ/kg.CO 2 |
| Energy consumption of purification part | 0 |
| CO 2 Recovery of energy consumption | 0.397MJ/kg.CO 2 |
The foregoing description is only of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. The protection scope of the present invention is subject to what is recited in the claims.
Claims (10)
1. Low-pressure CO 2 The low-temperature gas separation method is characterized by comprising the following steps of:
A. pressurizing raw material gas and utilizing waste heat: CO meeting the water content requirement 2 Raw materialsThe pressure of the gas is 0.2MPa-1.0MPa, the temperature is 5-40 ℃, the pressure is increased to 2.5-4.0 MPa by a raw material gas compressor, and the temperature is 70-85 ℃; then enters a tower bottom reboiler to provide heat for the purification system, and the temperature of the raw material gas is reduced to 21.6-35.5 ℃;
B.CO 2 initial cooling and cooling: the raw material gas obtained in the step A and coming out from the reboiler at the bottom of the tower enters CO 2 The initial cooler exchanges heat with two cold streams from the overhead gas throttling condenser and the overhead gas separator and is initially cooled to 12.3-25.5 ℃;
C.CO 2 deep condensing and liquefying: the raw gas after initial cooling enters CO 2 The deep condensing liquefier is further cooled to the temperature of minus 10 ℃ to minus 20 ℃ to condense more than 85 percent of raw material gas into liquid, CO 2 The cold energy required by the deep condensing liquefier is provided by an ammonia refrigerator group through liquid ammonia circulation, and CO is cooled 2 Returning the formed gas ammonia to the ammonia refrigerator group;
D. and (3) product separation and purification: c, deep condensing and liquefying the CO 2 Enters a stripping tower for separation and purification, and CO is obtained after purification 2 Liquid CO with purity of more than 99% 2 A product;
E. and (3) recycling tower top gas: the stripping tower top gas is cooled to minus 32 ℃ through a tower top gas throttling condenser, and then enters a tower top gas separator, and CO in the separated liquid phase 2 The content can reach 92%, then the temperature is reduced to minus 62 ℃, then the mixture enters a tower top gas throttling condenser to exchange heat with stripping tower top gas, the temperature is increased to minus 31 ℃, and then CO is introduced 2 The initial cooler exchanges heat with the raw gas obtained in the step A and coming out of the reboiler at the bottom of the tower to further recover cold energy, then the temperature is raised to 15-25 ℃, and the raw gas enters a raw gas compressor to be mixed with the raw gas and then enters a subsequent flow path, so that the CO is improved 2 Is a recovery rate of (2); the gaseous phase of the overhead separator contains CO 2 About 45 percent of hydrocarbon gas 55 percent is throttled, depressurized and cooled to about 65 ℃ below zero and enters CO 2 The temperature of the initial cooler is raised to 15-25 ℃ after cold energy recovery, and the initial cooler enters an in-station fuel system to realize the recovery and reutilization of fuel gas resources.
2. According to claim1. Said low pressure CO 2 A low-temperature gas separation method is characterized in that the raw material gas fed into the device in the step A requires CO 2 The content is as follows>75% water content<200ppm。
3. The low pressure CO of claim 1 2 The low-temperature gas separation method is characterized in that in the step A, the raw material gas is pressurized by adopting first-stage compression.
4. A method for achieving the low pressure CO of claim 1 2 Low pressure CO of gas cryogenic separation process 2 The gas low-temperature separation device is characterized by comprising a raw gas compressor and CO 2 Initial cooler and tower bottom reboiler, and feeding device CO meeting water content requirement 2 The feed gas enters the input end of a feed gas compressor, the output end of the feed gas compressor is connected with the input end of a tower bottom reboiler, and the output end of the tower bottom reboiler passes through CO 2 After heat exchange with liquid CO in the initial cooler 2 The outer conveying pipeline is connected.
5. The low pressure CO of claim 4 2 The low-temperature gas separation device is characterized by also comprising CO 2 The deep condensing liquefier and the stripping tower are arranged at the bottom in the stripping tower, and the output end of the tower bottom reboiler passes through CO 2 Initial cooler post-CO 2 The input end of the deep condensing liquefier is connected with CO 2 The output end of the deep condensing liquefier is connected with the input end of the stripping tower, and the liquid phase output end of the stripping tower is connected with liquid CO 2 The outer conveying pipeline is connected.
6. A low pressure CO according to claim 4 or 5 2 The gas low-temperature separation device is characterized by further comprising a tower top gas throttling condenser and a tower top gas separator, wherein the gas phase output end of the stripping tower is connected with the shell side input end of the tower top gas throttling condenser, the shell side output end of the tower top gas throttling condenser is connected with the input end of the tower top gas separator, the liquid phase output end of the tower top gas separator is connected with the tube side input end of the tower top gas throttling condenser, and the tube side output end of the tower top gas throttling condenserThrough CO 2 The initial cooler is connected with the input end of a raw material gas compressor, and the gas phase output end of the tower top gas separator passes through CO 2 The initial cooler is connected to the fuel gas system.
7. The low pressure CO of claim 4 2 The gas low-temperature separation device is characterized in that the raw material gas compressor is a screw compressor.
8. The low pressure CO of claim 4 2 The gas cryogenic separation plant is characterized in that the CO 2 The initial cooler is a three-flow plate-fin heat exchanger.
9. The low pressure CO of claim 4 2 The gas low-temperature separation device is characterized in that the tower bottom reboiler is a built-in plate-fin heat exchanger.
10. The low pressure CO of claim 6 2 The gas cryogenic separation plant is characterized in that the CO 2 Liquid ammonia inlet and CO of deep condensing liquefier 2 The ammonia outlet of the deep condensing liquefier is respectively connected with a liquid ammonia circulating pipeline of the refrigerating unit.
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Application publication date: 20220830 Assignee: Shandong Zhongke Industry Research Institute Technology Transfer Co.,Ltd. Assignor: Shandong Institute of petroleum and chemical engineering Contract record no.: X2024980017257 Denomination of invention: Low pressure CO2gas low-temperature separation method and device Granted publication date: 20231226 License type: Common License Record date: 20241010 Application publication date: 20220830 Assignee: Dongying Jiangyuan Chemical Co.,Ltd. Assignor: Shandong Institute of petroleum and chemical engineering Contract record no.: X2024980017093 Denomination of invention: Low pressure CO2gas low-temperature separation method and device Granted publication date: 20231226 License type: Common License Record date: 20241008 Application publication date: 20220830 Assignee: DONGYING GUOAN CHEMICAL Co.,Ltd. Assignor: Shandong Institute of petroleum and chemical engineering Contract record no.: X2024980017090 Denomination of invention: Low pressure CO2gas low-temperature separation method and device Granted publication date: 20231226 License type: Common License Record date: 20241008 |