CN111238166A - Refrigeration cycle system and method in carbon dioxide rectification separation process - Google Patents
Refrigeration cycle system and method in carbon dioxide rectification separation process Download PDFInfo
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- CN111238166A CN111238166A CN202010200137.7A CN202010200137A CN111238166A CN 111238166 A CN111238166 A CN 111238166A CN 202010200137 A CN202010200137 A CN 202010200137A CN 111238166 A CN111238166 A CN 111238166A
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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
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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
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B25/00—Machines, plants or systems, using a combination of modes of operation covered by two or more of the groups F25B1/00 - F25B23/00
- F25B25/02—Compression-sorption machines, plants, or systems
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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
- F25J2200/04—Processes or apparatus using separation by rectification in a dual pressure main column system
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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
- F25J2200/50—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the 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
- F25J2200/74—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
- 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
- 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
- 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
- F25J2270/90—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
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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
- F25J2270/902—Details about the refrigeration cycle used, e.g. composition of refrigerant, arrangement of compressors or cascade, make up sources, use of reflux exchangers etc.
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- 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
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- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
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- Y02C20/40—Capture or disposal of greenhouse gases of CO2
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Abstract
The invention discloses a refrigeration cycle system and a method in a carbon dioxide rectification separation process, and belongs to the technical field of carbon dioxide rectification separation. The refrigeration cycle system comprises an ammonia circulation system, a fluorine circulation system, a first gas-liquid separator, a first rectifying tower, a second rectifying tower and a second gas-liquid separator, wherein a raw gas input pipeline is arranged in the middle of the first rectifying tower, the top of the first rectifying tower is sequentially communicated with the ammonia circulation system, the first gas-liquid separator, the fluorine circulation system, the second gas-liquid separator and the second rectifying tower through gas transmission pipelines, and liquid carbon dioxide output pipelines are arranged at the bottoms of the first rectifying tower and the second rectifying tower. In the rectification separation process for producing liquid carbon dioxide, the fluorine circulation system is added, and the fluorine circulation system and the ammonia circulation system refrigerate the separation process together, so that the separation efficiency is improved, the product quality is improved, and the yield and the recovery rate are increased.
Description
Technical Field
The invention belongs to the technical field of carbon dioxide rectification separation, and particularly relates to a refrigeration cycle system and a method in a carbon dioxide rectification separation process.
Background
At present, the industrial production of carbon dioxide mainly utilizes industrial carbon-containing waste gas (CO)2Content > 80%) of the extract. The process mainly comprises two processes, wherein firstly, industrial waste gas is separated by a desulfurization section, an oxidation and dealkylation section and a dehydration section step by step and finally non-condensable gas N is removed by rectification and purification2、H2、CO、O2Obtaining high-purity liquid carbon dioxide; secondly, the industrial waste gas is subjected to a double-tower rectification process to remove CO2Impurities in (1), CO containing impurities2The raw material gas enters from the bottom of the first rectifying tower, components heavier than carbon dioxide are discharged from the bottom of the tower through rectification separation, other components exit from the top of the tower and enter the upper part of the second rectifying tower, components lighter than carbon dioxide are discharged from the top of the tower through rectification, and high-purity liquid carbon dioxide is obtained from the bottom of the tower. No matter what the composition of raw material gas and physical properties of each component are different, the purification of liquid carbon dioxide is carried out under the conditions of high pressure and low temperature.
In the conventional carbon dioxide rectification separation process, only an ammonia circulation system is used for refrigeration, referring to fig. 1, a large amount of heat is absorbed by a conventional condenser mainly through liquid ammonia gasification to provide cold energy, and gasified ammonia gas is compressed, cooled and liquefied through a screw compressor and then recycled. The traditional ammonia circulation system has high energy consumption, the separation efficiency needs to be improved, and the product quality and the yield also need to be improved.
Disclosure of Invention
The invention aims to solve the problems of high energy consumption and low separation efficiency caused by only using an ammonia circulation system for refrigeration in the conventional carbon dioxide rectification separation process, and provides a circulation system and a method for jointly refrigerating by using ammonia circulation and fluorine circulation in the carbon dioxide rectification separation process so as to improve the separation efficiency, yield and quality of carbon dioxide.
The technical scheme adopted by the invention is as follows:
the utility model provides a refrigeration cycle system among carbon dioxide rectification separation technology, includes ammonia circulation system, fluorine circulation system, first vapour and liquid separator, first rectifying column, second vapour and liquid separator, and first rectifying column middle part is equipped with feed gas input pipeline, and first rectifying column top is through gas transmission pipeline and ammonia circulation system, first vapour and liquid separator, fluorine circulation system, second vapour and liquid separator, second rectifying column order intercommunication, and the bottom of the tower of first rectifying column and second rectifying column all is equipped with liquid carbon dioxide output pipeline.
Further, ammonia circulation system includes first condenser, ammonia helical lobe compressor, and first condenser is located between first rectifying column and the first vapour and liquid separator, and through gas transmission pipeline intercommunication, ammonia helical lobe compressor passes through ammonia conveying pipeline with first condenser and links to each other.
Further, the lower parts of the first rectifying tower and the second rectifying tower are respectively provided with a first reboiler and a second reboiler, and the first reboiler and the second reboiler are plate reboilers.
Further, the freon circulation system comprises a second condenser, a freon screw compressor, a freon low-pressure storage tank and a fluorine gas-liquid heat exchanger, the top of the second condenser is respectively communicated with the top of the first gas-liquid separator and the top of the second rectifying tower, the bottom of the second condenser is communicated with the second gas-liquid separator, the lower part of the second condenser is communicated with the fluorine gas-liquid heat exchanger through a freon conveying pipeline, the freon screw compressor is respectively communicated with the first reboiler and the second reboiler through a freon conveying pipeline, the freon low-pressure storage tank is connected with the first reboiler, the second reboiler and the fluorine gas-liquid heat exchanger through a freon conveying pipeline, and the fluorine gas-liquid heat exchanger is further connected with the freon screw compressor through a freon conveying pipeline.
Furthermore, a subcooler is arranged on a liquid carbon dioxide output pipeline connected with the bottom of the second rectifying tower.
Further, the middle part of the second condenser is connected with an ammonia gas screw compressor through an ammonia conveying pipeline.
The refrigeration cycle system in the carbon dioxide rectification separation process is applied to the carbon dioxide rectification separation process.
The invention also provides a refrigeration method based on the refrigeration cycle system in the carbon dioxide rectification separation process, which comprises the following steps:
⑴ Freon gas coming out from the Freon screw compressor enters a plate reboiler at the bottom of the first rectifying tower and the second rectifying tower respectively through a Freon conveying pipeline, exchanges heat with liquid at the bottom of the rectifying tower to gasify part of the liquid, the gasified gas and the liquid flowing down from the top of the rectifying tower carry out mass transfer and heat transfer, at the moment, the gas Freon is cooled and liquefied, the liquefied Freon enters a Freon low-pressure storage tank, the liquid in the Freon low-pressure storage tank enters a plate condenser at the top of the second rectifying tower through the Freon conveying pipeline, exchanges heat with the gas at the top of the first rectifying tower to condense and liquefy the gas at the top of the tower, the Freon absorbs a large amount of heat to gasify, the gasified Freon and the liquid Freon flowing out from the Freon low-pressure storage tank exchange heat in a liquid heat exchanger to make the liquid Freon reach a lower evaporation temperature, the gas after heat exchange enters the Freon screw compressor through the Freon conveying pipeline to be compressed to become high-pressure Freon gas, and enters the first rectifying tower again to refrigerate at the bottom of the second rectifying tower to refrigerate the second rectifying tower, and the Freon;
⑵ compressing the ammonia gas in the ammonia conveying pipeline by a screw compressor, cooling and liquefying, then respectively feeding liquid ammonia into the middle parts of the first condenser and the second condenser, gasifying the liquid ammonia, feeding the gasified ammonia gas into the screw compressor by the ammonia conveying pipeline, and circulating the steps to perform ammonia refrigeration;
⑶ the raw gas passes through the first rectifying tower and the second rectifying tower, after refrigeration treatment in steps ⑴ and ⑵, the non-condensable gas is discharged as the vent tail gas through the top of the second gas-liquid separator, and liquid carbon dioxide is produced at the bottom of the first rectifying tower and the second rectifying tower.
Compared with the prior art, the invention has the beneficial effects that:
1. in the rectification separation process for producing liquid carbon dioxide, a fluorine circulation system is added, and the fluorine circulation system and the ammonia circulation system jointly refrigerate the separation process, so that the condensation temperature of rectification separation is reduced to-40 ℃, the rectification separation is cryogenic, the separation efficiency is improved, the product quality is improved, the yield and the recovery rate are increased, and the purity of the liquid carbon dioxide product is increased from 99.99% to 99.999%.
2. The Freon is used for providing heat energy and cold energy in the system, the latent heat of vaporization of the Freon is utilized, the latent heat of liquefaction of the Freon and the sensible heat of the Freon gas are also utilized, the multiple-effect utilization of the energy is achieved, an engineering heat source of a reboiler in the traditional process is omitted, the system is simplified, the equipment investment and the operation cost are reduced, and meanwhile, the purposes of energy conservation and consumption reduction are achieved.
Drawings
FIG. 1 is a schematic view of an ammonia recycle system in a conventional carbon dioxide distillation separation process;
FIG. 2 is a schematic structural view of the present invention;
the labels in the figure are: 1-a first gas-liquid separator, 2-a first condenser, 3-a first rectifying tower, 4-a first reboiler, 5-a fluorine low-pressure storage tank, 6-a subcooler, 7-a second rectifying tower, 8-a second reboiler, 9-a second condenser, 10-a second gas-liquid separator, 11-a fluorine liquid heat exchanger, 12-a freon screw compressor and 13-an ammonia screw compressor.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
Referring to fig. 2, the refrigeration cycle system in the carbon dioxide rectification separation process provided by the invention comprises an ammonia cycle system, a fluorine cycle system, a first gas-liquid separator, a first rectification tower, a second rectification tower and a second gas-liquid separator, wherein a feed gas input pipeline is arranged in the middle of the first rectification tower, the top of the first rectification tower is sequentially communicated with the ammonia cycle system, the first gas-liquid separator, the fluorine cycle system, the second gas-liquid separator and the second rectification tower through gas transmission pipelines, and liquid carbon dioxide output pipelines are arranged at the bottoms of the first rectification tower and the second rectification tower. The ammonia circulating system comprises a first condenser and an ammonia screw compressor, the first condenser is arranged between the first rectifying tower and the first gas-liquid separator and communicated with the first gas transmission pipeline, and the ammonia screw compressor is connected with the first condenser through an ammonia conveying pipeline. The lower parts of the first rectifying tower and the second rectifying tower are respectively provided with a first reboiler and a second reboiler, and the first reboiler and the second reboiler are plate reboilers. The system comprises a first condenser, a first Freon screw compressor, a first low-pressure storage tank, a first fluorine liquid heat exchanger, a second condenser, a first gas-liquid separator, a second condenser, a second reboiler, a second low-pressure storage tank, a second fluorine liquid heat exchanger, a second condenser top, a first gas-liquid separator top and a second rectifying tower top are communicated respectively, a second condenser bottom is communicated with the second gas-liquid separator, a second condenser lower portion is communicated with the fluorine liquid heat exchanger through a Freon conveying pipeline, the Freon screw compressor is communicated with the first reboiler and the second reboiler respectively through a Freon conveying pipeline, the fluorine low-pressure storage tank is connected with the first reboiler, the second reboiler and the fluorine liquid heat exchanger through a Freon conveying pipeline, and the fluorine liquid heat exchanger. A subcooler is arranged on a liquid carbon dioxide output pipeline connected with the bottom of the second rectifying tower. The middle part of the second condenser is connected with an ammonia gas screw compressor through an ammonia conveying pipeline.
Example 2
On the basis of embodiment 1, the invention also provides a method for refrigerating by a refrigeration cycle system in a carbon dioxide rectification separation process, which comprises the following steps:
⑴ Freon gas coming out from the Freon screw compressor enters a plate reboiler at the bottom of the first rectifying tower and the second rectifying tower respectively through a Freon conveying pipeline, exchanges heat with liquid at the bottom of the rectifying tower to gasify part of the liquid, the gasified gas and the liquid flowing down from the top of the rectifying tower carry out mass transfer and heat transfer, at the moment, the gas Freon is cooled and liquefied, the liquefied Freon enters a Freon low-pressure storage tank, the liquid in the Freon low-pressure storage tank enters a plate condenser at the top of the second rectifying tower through the Freon conveying pipeline, exchanges heat with the gas at the top of the first rectifying tower to condense and liquefy the gas at the top of the tower, the Freon absorbs a large amount of heat to gasify, the gasified Freon and the liquid Freon flowing out from the Freon low-pressure storage tank exchange heat in a liquid heat exchanger to make the liquid Freon reach a lower evaporation temperature, the gas after heat exchange enters the Freon screw compressor through the Freon conveying pipeline to be compressed to become high-pressure Freon gas, and enters the first rectifying tower again to refrigerate at the bottom of the second rectifying tower to refrigerate the second rectifying tower, and the Freon;
⑵ compressing the ammonia gas in the ammonia conveying pipeline by a screw compressor, cooling and liquefying, then respectively feeding liquid ammonia into the middle parts of the first condenser and the second condenser, gasifying the liquid ammonia, feeding the gasified ammonia gas into the screw compressor by the ammonia conveying pipeline, and circulating the steps to perform ammonia refrigeration;
⑶ the raw gas passes through the first rectifying tower and the second rectifying tower, after refrigeration treatment in steps ⑴ and ⑵, the non-condensable gas is discharged as the vent tail gas through the top of the second gas-liquid separator, and liquid carbon dioxide is produced at the bottom of the first rectifying tower and the second rectifying tower.
Example 3
Based on the embodiments 1 and 2, taking the double rectification towers producing 7 tons of liquid carbon dioxide per hour as an example, freon is changed into gas with the temperature of 50 ℃ and 2.85bar after passing through a screw compressor, and is changed into liquid with the temperature of-12 ℃ and 0.42bar after being shunted and passing through the reboilers at the bottoms of the two rectification towers, so that 200KW heat energy is provided for the system. Then the liquid is heat exchanged with gasified-40 ℃ low-temperature Freon through a heat exchanger, so that the temperature of the liquid Freon is reduced to-20 ℃. The cooled liquid Freon is evaporated by a plate condenser on the top of the second rectifying tower, so that the top gas from the first rectifying tower is liquefied, 155KW cold energy is provided for the system, and the rest cold energy in the process is provided by an ammonia circulating refrigeration system. The evaporated freon is changed into gas with the temperature of minus 40 ℃ and the pressure of 0.086bar, and the gas and the liquid freon enter a screw compressor for continuous recycling after heat exchange through a heat exchanger.
The fluorine cycle and the ammonia cycle together provide cold energy to reduce the condensation temperature to-38 ℃. The traditional ammonia circulation refrigeration can only reduce the temperature to-28 ℃ and increase the temperature from-28 ℃ to-38 ℃, so that the purity of the product can be increased from 99.99% to 99.999%, which is a qualitative change for the quality of the product, and simultaneously, along with the increase of the purity, the recovery rate of the product is increased from the previous 30% to the current 60%, namely, the carbon dioxide content of the vent tail gas is reduced from the previous 70% to the current 40%, so that the yield of the carbon dioxide is changed from the original 6 tons per hour to the current 7 tons per hour, and is increased by 16.67%.
The invention provides heat energy and cold energy for the carbon dioxide rectification separation process by utilizing the liquefaction latent heat, the gasification latent heat and the gas sensible heat of the Freon in the Freon circulation system. The fluorine circulation and the ammonia circulation are jointly refrigerated, so that the system is deep-cooled, the separation efficiency is improved, the content of carbon dioxide in tail gas emission is reduced, and the product yield is improved. In addition, no extra engineering heat source is needed to be provided for the system, so that the energy consumption is reduced, the process flow is simplified, and the equipment investment and the operation cost are reduced.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (8)
1. A refrigeration cycle system in a carbon dioxide rectification separation process is characterized in that: the system comprises an ammonia circulation system, a fluorine circulation system, a first gas-liquid separator, a first rectifying tower, a second rectifying tower and a second gas-liquid separator, wherein a raw gas input pipeline is arranged in the middle of the first rectifying tower, the top of the first rectifying tower is sequentially communicated with the ammonia circulation system, the first gas-liquid separator, the fluorine circulation system, the second gas-liquid separator and the second rectifying tower through gas transmission pipelines, and liquid carbon dioxide output pipelines are arranged at the bottoms of the first rectifying tower and the second rectifying tower.
2. The system of claim 1, wherein: the ammonia circulating system comprises a first condenser and an ammonia screw compressor, the first condenser is arranged between the first rectifying tower and the first gas-liquid separator and communicated with the first gas transmission pipeline, and the ammonia screw compressor is connected with the first condenser through an ammonia conveying pipeline.
3. The system of claim 2, wherein: the lower parts of the first rectifying tower and the second rectifying tower are respectively provided with a first reboiler and a second reboiler, and the first reboiler and the second reboiler are plate reboilers.
4. The system of claim 3, wherein: the system comprises a first condenser, a first Freon screw compressor, a first low-pressure storage tank, a first fluorine liquid heat exchanger, a second condenser, a first gas-liquid separator, a second condenser, a second reboiler, a second low-pressure storage tank, a second fluorine liquid heat exchanger, a second condenser top, a first gas-liquid separator top and a second rectifying tower top are communicated respectively, a second condenser bottom is communicated with the second gas-liquid separator, a second condenser lower portion is communicated with the fluorine liquid heat exchanger through a Freon conveying pipeline, the Freon screw compressor is communicated with the first reboiler and the second reboiler respectively through a Freon conveying pipeline, the fluorine low-pressure storage tank is connected with the first reboiler, the second reboiler and the fluorine liquid heat exchanger through a Freon conveying pipeline, and the fluorine liquid heat exchanger.
5. The system of claim 4, wherein: a subcooler is arranged on a liquid carbon dioxide output pipeline connected with the bottom of the second rectifying tower.
6. The system of claim 5, wherein: the middle part of the second condenser is connected with an ammonia gas screw compressor through an ammonia conveying pipeline.
7. Use of the system of claim 6 in a carbon dioxide rectification separation process.
8. A refrigeration method in a carbon dioxide rectification separation process by using the system of claim 6, which is characterized in that: the method comprises the following steps:
⑴ Freon gas coming out from the Freon screw compressor enters a plate reboiler at the bottom of the first rectifying tower and the second rectifying tower respectively through a Freon conveying pipeline, exchanges heat with liquid at the bottom of the rectifying tower to gasify part of the liquid, the gasified gas and the liquid flowing down from the top of the rectifying tower carry out mass transfer and heat transfer, at the moment, the gas Freon is cooled and liquefied, the liquefied Freon enters a Freon low-pressure storage tank, the liquid in the Freon low-pressure storage tank enters a plate condenser at the top of the second rectifying tower through the Freon conveying pipeline, exchanges heat with the gas at the top of the first rectifying tower to condense and liquefy the gas at the top of the tower, the Freon absorbs a large amount of heat to gasify, the gasified Freon and the liquid Freon flowing out from the Freon low-pressure storage tank exchange heat in a liquid heat exchanger to make the liquid Freon reach a lower evaporation temperature, the gas after heat exchange enters the Freon screw compressor through the Freon conveying pipeline to be compressed to become high-pressure Freon gas, and enters the first rectifying tower again to refrigerate at the bottom of the second rectifying tower to refrigerate the second rectifying tower, and the Freon;
⑵ compressing the ammonia gas in the ammonia conveying pipeline by a screw compressor, cooling and liquefying, then respectively feeding liquid ammonia into the middle parts of the first condenser and the second condenser, gasifying the liquid ammonia, feeding the gasified ammonia gas into the screw compressor by the ammonia conveying pipeline, and circulating the steps to perform ammonia refrigeration;
⑶ the raw gas passes through the first rectifying tower and the second rectifying tower, after refrigeration treatment in steps ⑴ and ⑵, the non-condensable gas is discharged as the vent tail gas through the top of the second gas-liquid separator, and liquid carbon dioxide is produced at the bottom of the first rectifying tower and the second rectifying tower.
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| CN111895724A (en) * | 2020-07-01 | 2020-11-06 | 陕西裕隆气体有限公司 | Carbon dioxide dehydration method |
| CN113318469A (en) * | 2021-05-29 | 2021-08-31 | 安徽金禾实业股份有限公司 | Rectification treatment method for HCl (hydrochloric acid) in sucralose chlorination tail gas |
| CN114485051A (en) * | 2022-01-24 | 2022-05-13 | 广州市华达石化有限公司 | Liquid ammonia dual-condition refrigerating system and liquid carbon dioxide production equipment |
| CN115790078A (en) * | 2022-11-29 | 2023-03-14 | 北京恒泰洁能科技有限公司 | CO (carbon monoxide) 2 Liquefaction process and cold box |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111895724A (en) * | 2020-07-01 | 2020-11-06 | 陕西裕隆气体有限公司 | Carbon dioxide dehydration method |
| CN113318469A (en) * | 2021-05-29 | 2021-08-31 | 安徽金禾实业股份有限公司 | Rectification treatment method for HCl (hydrochloric acid) in sucralose chlorination tail gas |
| CN114485051A (en) * | 2022-01-24 | 2022-05-13 | 广州市华达石化有限公司 | Liquid ammonia dual-condition refrigerating system and liquid carbon dioxide production equipment |
| CN114485051B (en) * | 2022-01-24 | 2023-06-20 | 广州市华达石化有限公司 | Liquid ammonia double-working-condition refrigerating system and liquid carbon dioxide production equipment |
| CN115790078A (en) * | 2022-11-29 | 2023-03-14 | 北京恒泰洁能科技有限公司 | CO (carbon monoxide) 2 Liquefaction process and cold box |
| CN115790078B (en) * | 2022-11-29 | 2023-09-29 | 北京恒泰洁能科技有限公司 | CO (carbon monoxide) 2 Liquefying process and cold box |
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