CN113896198B - System and method for generating gas and liquid carbon dioxide by methanol washing - Google Patents
System and method for generating gas and liquid carbon dioxide by methanol washing Download PDFInfo
- Publication number
- CN113896198B CN113896198B CN202111295451.9A CN202111295451A CN113896198B CN 113896198 B CN113896198 B CN 113896198B CN 202111295451 A CN202111295451 A CN 202111295451A CN 113896198 B CN113896198 B CN 113896198B
- Authority
- CN
- China
- Prior art keywords
- tower
- gas
- carbon dioxide
- product
- liquid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
The invention belongs to the technical field of coal chemical industry, and relates to methanol washing generated gas and liquid dioxideThe system and the method for carbonizing carbon comprise an evaporation tower, an alcohol washing tower reboiler, an alcohol washing tower, a carbon dioxide liquefaction condenser, a carbon dioxide product tower and a refrigerant compressor; the evaporation tower, the alcohol washing tower reboiler, the alcohol washing tower, the carbon dioxide liquefaction condenser and the carbon dioxide product tower are communicated in sequence; the alcohol washing tower is respectively communicated with the evaporation tower and the alcohol washing tower reboiler; the carbon dioxide product tower is communicated with the alcohol washing tower; the refrigerant compressor returns to the refrigerant compressor after passing through the carbon dioxide liquefaction condenser; the evaporation tower is provided with a raw material inlet; and a product outlet is formed in the carbon dioxide product tower. The invention can simplify CO 2 Production flow of CO 2 Purifying and enriching; refrigerant gas-liquid mode circulation, energy consumption reduction and adjustment of CO in gas-liquid production 2 The product is suitable for large-scale production.
Description
Technical Field
The invention belongs to the technical field of coal chemical industry, and relates to a system and a method for generating gas and liquid carbon dioxide by methanol washing.
Background
Low temperature methanol scrubbing (Rectisol) is a gas purification process. The process is a typical physical absorption method, low-temperature methanol is used as an absorption solvent, the characteristic that the methanol has great solubility to acid gas at low temperature is utilized to remove the acid gas in feed gas, and the low-temperature methanol washing process is operated at low temperature (-60 ℃) and CO at low temperature due to higher vapor pressure of the methanol 2 And H 2 The solubility of S increases significantly with decreasing temperature, thus requiring a smaller amount of solvent and smaller equipment; the process gas has high purification degree, and can convert CO in the gas 2 Removing to less than 20ppm of hydrogen and removing to obtain hydrogen 2 S is less than 0.1ppm, and the desulfurization and decarburization of the gas can be separated in the same tower; however, the difficulty of the technology is the complex process flow of gas analysis and cold recovery after adsorption, and the process flow is long, so that the efficiency is highLow cost and high treatment cost.
In addition, for CO in coal chemical industry 2 Or sulfur-containing gas treatment production, the common method is flash evaporation, namely flash evaporation is carried out to low pressure and low temperature to flash off carbon dioxide gas, then liquid carbon dioxide is produced in compression refrigeration, although CO can be realized 2 The technology has the difficulties of complicated process flow of gas desorption and cold recovery after adsorption, long process flow and large pressure change, so that the treatment cost is high, the tail gas is low in pressure and low in purity, and part of dissolved gas cannot be recovered.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides a system and a method for generating gas and liquid carbon dioxide by methanol washing, which can simplify CO 2 Production flow of CO 2 Purifying and enriching; refrigerant gas-liquid mode circulation, energy consumption reduction and adjustment of CO in gas-liquid production 2 The product is suitable for large-scale production.
In order to achieve the purpose, the invention adopts the technical scheme that:
a system for generating gas and liquid carbon dioxide by washing methanol comprises an evaporation tower, an alcohol washing tower reboiler, an alcohol washing tower, a carbon dioxide liquefaction condenser, a carbon dioxide product tower and a refrigerant compressor; the evaporation tower, the alcohol washing tower reboiler, the alcohol washing tower, the carbon dioxide liquefaction condenser and the carbon dioxide product tower are communicated in sequence; the alcohol washing tower is respectively communicated with the evaporation tower and the alcohol washing tower reboiler; the carbon dioxide product tower is communicated with the alcohol washing tower; the refrigerant compressor returns to the refrigerant compressor after passing through the carbon dioxide liquefaction condenser; the evaporation tower is provided with a raw material inlet; a gas-phase product outlet is formed in the alcohol washing tower; and a liquid-phase product outlet is arranged on the carbon dioxide product tower.
Furthermore, the system for generating gas and liquid carbon dioxide by washing methanol also comprises a refrigerant condenser and a refrigerant storage tank; and the refrigerant compressor is communicated with the carbon dioxide liquefaction condenser through a refrigerant condenser and a refrigerant storage tank in sequence.
Further, the system for generating gas and liquid carbon dioxide by washing methanol also comprises an evaporation tower reboiler arranged between the refrigerant compressor and the refrigerant condenser; and two ends of the reboiler of the evaporation tower are respectively communicated with the evaporation tower.
Furthermore, the system for generating the gas and the liquid carbon dioxide by methanol washing also comprises a condensate separator and a gas cooler; the reboiler of the alcohol washing tower is communicated with the alcohol washing tower through a condensate separator and a gas cooler in sequence; the condensate separator is communicated with the evaporation tower.
Furthermore, the system for generating gas and liquid carbon dioxide by washing methanol also comprises a raw material preheater communicated with the raw material inlet; the raw material preheater is also communicated with the evaporation tower.
Furthermore, the system for generating gas and liquid carbon dioxide by washing methanol also comprises a product tower reboiler communicated with the carbon dioxide product tower.
A method for producing gas and liquid carbon dioxide by methanol washing comprises the following steps:
1) The raw material enters an evaporation tower and is evaporated at the pressure of 1.2-2.0 MP and the temperature of-10-45 ℃, the resolved gas phase in the raw material rises, and the liquid phase falls down to form a tower top gas phase and a tower bottom liquid phase; the liquid phase at the bottom of the tower is subjected to heat compensation by an evaporation tower reboiler, then the analyzed gas phase rises to the evaporation tower, the gas phase at the top of the tower is condensed and separated by an alcohol washing tower reboiler to form liquid and gas, the liquid flows back to the evaporation tower, and the gas enters the alcohol washing tower;
2) Rectifying the gas at-25-38 deg.C in alcohol washing tower to obtain CO 2 Gas products and bottom liquid of an alcohol washing tower; after the tower bottom liquid of the alcohol washing tower is subjected to heat supplementing and temperature rising through an alcohol washing tower reboiler, part of the tower bottom liquid is vaporized to maintain the ascending gas of rectification, and the unvaporized part of the tower bottom liquid flows back to the top of the evaporation tower for mass transfer; the gas entering the alcohol washing tower simultaneously also flows with the CO refluxed from the carbon dioxide product tower 2 The liquid product is subjected to mass transfer, heavy components move downwards, and CO is generated 2 And light components of low boiling point, CO 2 Finishing primary purification of the gas; CO2 2 The gas product rises to the top of the alcohol washing tower, one part of the gas product is directly output as the product, and the other part of the gas product is condensed by a carbon dioxide liquefaction condenser, exchanges heat with the circulating refrigerant sent by a refrigerant storage tank, is condensed and then enters a carbon dioxide product tower;
3) Condensed CO in a carbon dioxide product column 2 Separating light components and CO from the gas product 2 Liquid product, light component rise to the top of the carbon dioxide product tower and get condensate and tail gas after the deep condenser cooling, the tail gas is collected and reused, the condensate flows back to the carbon dioxide product tower for mass transfer; CO2 2 The liquid product descends to the bottom of the carbon dioxide product tower, and most of CO 2 The liquid product is directly output as a product, and a small part of CO is output 2 The liquid product flows back to the alcohol washing tower for mass transfer.
Further, the raw material is carbon-rich methanol after methanol washing medium-pressure flash evaporation or sulfur-rich methanol after methanol washing medium-pressure flash evaporation.
Further, when the raw material is sulfur-rich methanol after methanol washing medium-pressure flash evaporation, sulfur-rich gas is also generated after rectification in the alcohol washing tower in the step 1), and is directly recovered from the side of the alcohol washing tower.
Further, in the step 2), the refrigerant cycle process is that the gaseous refrigerant is compressed by the refrigerant compressor, then is subjected to heat exchange and temperature reduction by the reboiler of the evaporation tower, is subjected to secondary temperature reduction and condensation by the refrigerant condenser to form liquid refrigerant, enters the refrigerant storage tank for pressure reduction, is heated by the carbon dioxide liquefaction condenser to become gas phase, and returns to the refrigerant compressor again to form cycle; the gaseous refrigerant is a gas-phase refrigerant added from the outside or circulated in the system.
The invention has the beneficial effects that:
1. according to the invention, raw materials sequentially pass through the evaporation tower, the alcohol washing tower and the carbon dioxide product tower, carbon dioxide-rich gas is produced through evaporation, and the evaporated carbon dioxide carries heat to be internally circulated, so that the tower height and the energy consumption of material circulation are effectively reduced; purifying carbon dioxide gas by an alcohol washing tower (rectification), producing high-purity carbon dioxide gas from the carbon-rich methanol, concentrating part of hydrogen sulfide produced from the sulfur-rich methanol, wherein the purity of the product is over 99.99 percent, and the purity of the carbon dioxide product of the sulfur-rich methanol production liquid can be over 99.5 percent, thus realizing CO 2 The method has the advantages of high enrichment and purification of sulfur-rich gas, recovery of non-condensable gas in the material, simple production method, short flow, and realization of regeneration of methanol-washed carbon dioxide and carbon capture to the maximum extent through medium-pressure temperature rising desorptionTo purification of carbon dioxide and recovery of methanol; and the compression process of liquid carbon dioxide produced in a low-pressure area is omitted, so that great energy conservation is realized.
2. The invention adopts the combination of evaporation, alcohol washing (rectification) and condensation (liquefaction), and evaporation-rectification-liquefaction to obtain the heat pump circulation flow of the refrigerant compression condensation refrigeration evaporation method, and the flow has the characteristic of energy conservation; the dissolved carbon dioxide is desorbed and released by heating, the CO2 treatment process is simplified, a series of low-pressure regeneration systems such as flash evaporation and the like are omitted, the process is simple, and the yield is high.
3. In the invention, the refrigerant is in a gas-liquid circulation mode, can exchange heat and cold, maximizes closed-loop circulation cold and heat, directly adjusts and produces liquid carbon dioxide products, and has the advantages of simple process and low heat and cold consumption compared with the traditional carbon capture liquefaction without a carbon dioxide gas compressor.
4. In the present invention, CO is absorbed from the absorption 2 Or recovering CO in different states from methanol raw material containing sulfur gas 2 The product or the sulfur-rich gas is simultaneously recycled for the medium-pressure area semi-lean methanol, so that the production process can be matched with methanol washing, the amount of carbon dioxide produced by evaporation is large, the method is suitable for large-scale production, and the energy consumption is low.
Drawings
FIG. 1 is a schematic diagram of a system provided in embodiment 1 of the present invention;
FIG. 2 is a schematic diagram of a system provided in embodiment 2 of the present invention;
wherein:
1-an evaporation column; 2-reboiler of alcohol washing tower; 3-a condensate separator; 4-gas cooler; 5-alcohol washing tower; 6-an evaporation tower reboiler; 7-refrigerant condenser; 8-a refrigerant storage tank; 9-carbon dioxide liquefaction condenser; 10-carbon dioxide product column; 11-deep condenser; 12-product column reboiler; 13-carbon dioxide reflux pump; 14-refrigerant compressor; 15-raw material preheater.
Detailed Description
The present invention will now be described in detail with reference to the drawings and examples.
Example 1
Referring to fig. 1, the system for producing gas and liquid carbon dioxide by methanol washing provided by the embodiment includes an evaporation tower 1, an alcohol washing tower reboiler 2, an alcohol washing tower 5, a carbon dioxide liquefaction condenser 9, a carbon dioxide product tower 10, and a refrigerant compressor 14; the top of the evaporation tower 1 is communicated with the side of an alcohol washing tower 5 through an alcohol washing tower reboiler 2; the tower top of the alcohol washing tower 5 is communicated with the tower side of a carbon dioxide product tower 10 through a carbon dioxide liquefaction condenser 9; the tower bottom of the alcohol washing tower 5 is respectively communicated with the upper tower sides of the alcohol washing tower reboiler 2 and the evaporation tower 1; the refrigerant compressor 14 is communicated with the refrigerant compressor 14 through the carbon dioxide liquefaction condenser 9; the bottom of the carbon dioxide product tower 10 is communicated with the alcohol washing tower 5. Also comprises a refrigerant condenser 7 and a refrigerant storage tank 8; the refrigerant compressor 14 is communicated with the carbon dioxide liquefaction condenser 9 through the refrigerant condenser 7 and the refrigerant storage tank 8 in sequence. Also comprises a condensate separator 3 and a gas cooler 4; the condensate separator 3 is respectively communicated with the evaporation tower 1, the alcohol washing tower reboiler 2 and the gas cooler 4; the gas cooler 4 is communicated with an alcohol washing tower 5. An evaporation tower reboiler 6 arranged between the refrigerant compressor 14 and the refrigerant condenser 7; the reboiler 6 of the evaporation tower is also communicated with the bottom of the evaporation tower 1 and the side of the evaporation tower 1 respectively. Also comprises a raw material preheater 15; the raw material preheater 15 is respectively communicated with the bottom of the evaporation tower 1 and the side of the middle part of the evaporation tower 1. Also included is a product column reboiler 12 in communication with carbon dioxide product column 10.
Specifically, a raw material inlet is arranged at the side of the middle tower of the evaporation tower 1; the bottom of the evaporation tower 1 is divided into two paths, one path is communicated with the lower tower side of the evaporation tower 1 after passing through an evaporation tower reboiler 6, and the other path is subjected to the next process (gas stripping or recycling) after passing through a raw material preheater 15; the top of the evaporation tower 1 is communicated with an alcohol washing tower reboiler 2.
The structure of the reboiler 2 of the alcohol washing tower comprises a left chamber and a right chamber, wherein heat exchange tubes are respectively arranged in the left chamber and the right chamber to realize heat exchange. The top of the evaporation tower 1 passes through a left cavity of an alcohol washing tower reboiler 2 and then enters the side of a condensate separator 3; the bottom of the condensate separator 3 is communicated with the upper tower side of the evaporation tower 1; the top of the condensate separator 3 passes through a gas cooler 4 and is divided into two paths, one path returns to the tower side of the condensate separator 3, and the other path enters the left upper tower side of an alcohol washing tower 5.
The bottom of the alcohol washing tower 5 is divided intoOne path is directly communicated with the upper tower side of the evaporation tower 1, and the other path returns to the middle tower side of the alcohol washing tower 5 after passing through a right side cavity of the alcohol washing tower reboiler 2; one path of gas CO is directly recovered from the top of the 5-tower of the alcohol washing tower 2 The product (a gas phase product outlet is arranged at the top of the alcohol washing tower 5), and the other path of the product enters the tower side at the upper part of a carbon dioxide product tower 10 after passing through a carbon dioxide liquefying condenser 9.
In the carbon dioxide product tower 10, the top of the carbon dioxide product tower 10 passes through a deep condenser 11 and then tail gas is collected for recycling, and one path of tail gas returns to the carbon dioxide product tower 10; the bottom of the carbon dioxide product tower 10 is divided into three paths, the first path is provided with a liquid-phase product outlet, and liquid CO can be directly recovered 2 The second path of the product returns to the tower side at the lower part of the carbon dioxide product tower 10 through a product tower reboiler 12, and the third path returns to the tower side at the upper right part of the alcohol washing tower 5 through a carbon dioxide reflux pump 13.
In the whole system, gaseous refrigerant from the outside returns to the refrigerant compressor 14 to form a circulation loop after passing through the refrigerant compressor 14, the evaporation tower reboiler 6, the refrigerant condenser 7, the refrigerant storage tank 8 and the carbon dioxide liquefaction condenser 9.
In the invention, the refrigerant is a common refrigerant in chemical production, and specifically, the adaptive refrigerant can be selected according to pressure and temperature.
The method for producing gas and liquid carbon dioxide by methanol washing provided by the embodiment is described by taking carbon-rich methanol subjected to medium-pressure flash evaporation in methanol washing as a raw material: the method comprises the following steps:
1) The raw material enters an evaporation tower 1, the raw material is evaporated under the pressure of 1.2-2.0 MP and the temperature of minus 10-45 ℃, the resolved gas phase in the raw material rises, and the liquid phase falls down to form a tower top gas phase and a tower bottom liquid phase; the liquid phase at the bottom of the tower is subjected to heat compensation by an evaporation tower reboiler 6, then the analyzed gas phase rises to the evaporation tower 1, the gas phase at the top of the tower is condensed and separated by an alcohol washing tower reboiler 2 to form liquid and gas, the liquid flows back to the evaporation tower 1, and the gas enters an alcohol washing tower 5;
2) The gas is rectified to generate CO at the temperature of minus 25 to minus 38 ℃ through an alcohol washing tower 5 2 Gas products and bottom liquid of an alcohol washing tower; the tower bottom liquid of the alcohol washing tower is heated up by the heat supply of the reboiler 2 of the alcohol washing tower, then is partially vaporized to maintain the rectification of the rising gas, and the unvaporized part flows back to the tower 1 of the evaporation towerTop mass transfer; while the gas entering the alcohol scrubber 5 is also mixed with the CO reflux from the carbon dioxide product column 10 2 The liquid product is subjected to mass transfer, heavy components move downwards, and CO 2 And light components with low boiling point move upwards, and CO2 gas is primarily purified; CO2 2 The gas product rises to the top of the alcohol washing tower 5, one part of the gas product is directly output as a product, and the other part of the gas product is condensed by a carbon dioxide liquefaction condenser 9, exchanges heat with the circulating refrigerant sent by a refrigerant storage tank 8 and is condensed, and then enters a carbon dioxide product tower 10;
3) Condensed CO in the carbon dioxide product column 10 2 Separating light components and CO from the gas product 2 Liquid products and light components rise to the top of a carbon dioxide product tower 10 and are cooled by a deep condenser 11 to obtain condensate and tail gas, the tail gas is collected and recycled, and the condensate flows back to the carbon dioxide product tower 10 for mass transfer; CO2 2 The liquid product descends to the bottom of the carbon dioxide product tower 10, most of the CO 2 The liquid product is directly output as a product, and a small part of CO is output 2 The liquid product flows back to the alcohol washing tower 5 for mass transfer.
Specifically, in step 1), before entering the evaporation tower 1, the raw material is preheated by a raw material preheater 15, and then enters the evaporation tower 1 from a raw material inlet, and is evaporated at a pressure of 1.2 to 2.0MP and a temperature of-10 to 45 ℃ to generate a tower top gas phase (carbon dioxide gas phase component evaporated from the raw material) and a tower bottom liquid phase (methanol liquid not evaporated from the raw material), wherein a part of the tower bottom liquid phase exchanges heat with a refrigerant flowing through the evaporation tower reboiler 6 by the evaporation tower reboiler 6, the refrigerant is cooled, the temperature of the tower bottom liquid phase is raised and returned to the right lower tower side of the evaporation tower 1, and the other part of the tower bottom liquid phase exchanges heat with the raw material by the raw material preheater 15 and is cooled to the next process (gas stripping or recycling as low-lean methanol liquid); the gas phase at the top of the tower is cooled by a left cavity of an alcohol washing tower reboiler 2, and enters a condensate separator 3 for separation into gas and condensate, and the condensate returns to the upper tower side of the evaporation tower 1 from the bottom of the tower; the gas is continuously condensed by a gas cooler 4 from the top of the condensate separator 3 and divided into two paths, the condensate returns to the tower side of the condensate separator 3 to be continuously condensed, and the condensed gas enters the left upper tower side of an alcohol washing tower 5;
in step 2), the gas is in the alcohol washing tower 5 at the temperatureRectifying at-25-38 deg.C to produce CO 2 Gas products and bottom liquid of an alcohol washing tower; the bottom liquid of the alcohol washing tower flows towards the bottom of the alcohol washing tower 5 and finally flows out of the bottom of the tower, one part of the bottom liquid is subjected to gas phase heat exchange with the top of the evaporation tower 1 through the alcohol washing tower reboiler 2, is heated and supplemented, then returns to the alcohol washing tower 5 for continuous rectification, and the other part of the bottom liquid flows to the evaporation tower 1 for evaporation; CO2 2 The gas product flows to the top of the alcohol washing tower 5 and is finally discharged from the top of the tower, and part of the gas product is directly recycled to obtain CO 2 The other part of the gas product is condensed and cooled by the circulating refrigerant sent by the carbon dioxide liquefaction condenser 9 and the refrigerant compressor 14 to obtain cooling liquid; meanwhile, the gas in the alcohol washing tower 5 and the carbon dioxide refluxed from the carbon dioxide product tower 10 carry out mass transfer, heavy components continuously move downwards to the bottom of the alcohol washing tower 5, and CO 2 Primarily purifying and enriching the gas;
in the step 2), the refrigerant cycle process is that the gas refrigerant added from the outside is compressed by the refrigerant compressor 14, then is subjected to heat exchange and temperature reduction by the evaporation tower reboiler 6, is subjected to secondary temperature reduction by the refrigerant condenser 7 to form liquid refrigerant, flows into the refrigerant storage tank 8, is heated by the carbon dioxide liquefaction condenser 9 to become gas, and returns to the refrigerant compressor 14 again for cycle;
in the step 3), the cooling liquid enters the carbon dioxide product tower 10 mainly for removing light components, and the light components and CO are obtained by separating the cooling liquid 2 The liquid product, the light component deep condenser 11 generates condensate and tail gas (namely noncondensable gas), the tail gas is directly collected and recycled, the condensate returns to the carbon dioxide product tower 10 to continuously condense and separate CO 2 A liquid product; CO2 2 The liquid product flows out from the bottom of the carbon dioxide product tower 10, and part of the liquid product directly recovers liquid CO from a liquid-phase product outlet 2 Part of the product returns to the right upper part of the alcohol washing tower 5 through the carbon dioxide reflux pump 13 to transfer mass with the alcohol washing tower 5, thereby realizing CO 2 And (3) primarily purifying and enriching the gas product, wherein in the implementation, a part of the gas product is heated by a product tower reboiler 12 and then returns to the tower side at the lower part of the carbon dioxide product tower 10 to realize tower bottom heat supplement.
In the embodiment, the absorption of CO is realized through the evaporation tower 1, the alcohol washing tower 5, the carbon dioxide product tower 10 and the refrigerant circulation 2 Is recovered from methanolCO in different states 2 The product and the refrigerant circulate in the loop in a gas-liquid mode, so that the heat exchange and the cold exchange can be realized, and the two CO in different states can be adjusted 2 Product, realization of para-CO 2 The purity of the obtained carbon dioxide product can reach more than 99.99 percent, and CO is simplified 2 The treatment process saves time and has low energy consumption; in addition, the production process of the embodiment can be matched with methanol washing, is suitable for large-scale production and has low energy consumption. The evaporation pressure is 1.2-2.0 MP, carbon dioxide gas and carbon dioxide liquid are produced in the medium-pressure area, and most of the unevaporated tower bottom liquid phase can be reused as semi-lean methanol after carbon dioxide is produced from carbon-rich methanol under the pressure.
Example 2
Referring to fig. 2, in contrast to example 1, when the feedstock is sulfur-rich methanol, a sulfur-rich gas outlet is provided in the right middle column side of the alcohol scrubber 5. And the system does not contain product column reboiler 12.
Specifically, a raw material inlet is arranged at the side of the middle tower of the evaporation tower 1; the tower bottom of the evaporation tower 1 is divided into two paths, one path is communicated with the tower side at the lower part of the evaporation tower 1 after passing through an evaporation tower reboiler 6, and the other path is subjected to the next working procedure (gas stripping or recycling) after passing through a raw material preheater 15; the top of the evaporation tower 1 is communicated with an alcohol washing tower reboiler 2.
The top of the evaporation tower 1 passes through a left cavity of an alcohol washing tower reboiler 2 and then enters the side of a condensate separator 3; the bottom of the condensate separator 3 is communicated with the upper tower side of the evaporation tower 1; the top of the condensate separator 3 passes through a gas cooler 4 and is divided into two paths, one path returns to the tower side of the condensate separator 3, and the other path enters the left upper tower side of an alcohol washing tower 5.
The bottom of the alcohol washing tower 5 is divided into two paths, one path is directly communicated with the upper tower side of the evaporation tower 1, and the other path returns to the middle tower side of the alcohol washing tower 5 after passing through the right chamber of the reboiler 2 of the alcohol washing tower; one path of the top of the alcohol washing tower 5 is provided with a gas-phase product outlet which can directly recycle gas CO 2 The other path of the product passes through a carbon dioxide liquefaction condenser 9 and then enters the upper tower side of a carbon dioxide product tower 10; a sulfur-rich gas outlet is arranged at the right middle tower side of the alcohol washing tower 5.
In the carbon dioxide product tower 10, the top of the carbon dioxide product tower 10 passes throughCollecting tail gas for recycling after the deep condenser 11, and returning one path of tail gas to the carbon dioxide product tower 10; the bottom of the carbon dioxide product tower 10 is divided into two paths, the first path is provided with a liquid-phase product outlet and can directly recover liquid CO 2 The second path of the product returns to the right upper tower side of the alcohol washing tower 5 through a carbon dioxide reflux pump 13.
In the whole system, the gaseous refrigerant from the outside returns to the refrigerant compressor 14 to form a circulation loop after passing through the refrigerant compressor 14, the evaporation tower reboiler 6, the refrigerant condenser 7, the refrigerant storage tank 8 and the carbon dioxide liquefaction condenser 9.
The method for producing gas and liquid carbon dioxide by methanol washing provided by the embodiment is described by taking sulfur-rich methanol subjected to medium-pressure flash evaporation in methanol washing as a raw material:
in step 1), before entering the evaporation tower 1, the raw material is preheated by a raw material preheater 15, then enters the evaporation tower 1 from a raw material inlet, and is evaporated at the pressure of 1.2-2.0 MP and the temperature of-10-45 ℃ to generate a tower top gas phase (carbon dioxide and sulfur-containing gas phase components evaporated from the raw material) and a tower bottom liquid phase (methanol liquid not evaporated from the raw material), wherein one part of the tower bottom liquid phase exchanges heat with a refrigerant flowing through the evaporation tower reboiler 6 by the evaporation tower reboiler 6, the refrigerant is cooled, the temperature of the tower bottom liquid phase is raised and returned to the right lower tower side of the evaporation tower 1, and the other part of the tower bottom liquid phase exchanges heat with the raw material by the raw material preheater 15 and is cooled to the next process (gas stripping); the gas phase at the top of the tower is cooled by a left cavity of an alcohol washing tower reboiler 2 and then enters a condensate separator 3 to be separated into gas and condensate, and the condensate returns to the upper tower side of the evaporation tower 1 from the bottom of the tower; the gas is divided into two paths after passing through a gas cooler 4 from the top of the tower, one path returns to the side of the condensate separator 3 to be continuously condensed, and the other path enters the side of the upper left tower of an alcohol washing tower 5;
in the step 2), the gas is rectified in an alcohol washing tower 5 at the temperature of minus 25 to minus 38 ℃ to generate CO 2 Gas products, sulfur-rich gas products and alcohol scrubber bottoms; the sulfur-rich gas product is discharged from the right middle tower side of the alcohol washing tower 5 and collected; the bottom liquid of the alcohol washing tower flows towards the bottom of the alcohol washing tower 5 and finally flows out of the bottom of the alcohol washing tower, one part of the bottom liquid is subjected to heat exchange with the gas phase at the top of the evaporation tower 1 through the alcohol washing tower reboiler 2 and then returns to the alcohol washing tower 5 for continuous rectification, and the other part of the bottom liquid flows to the evaporation tower 1 for evaporation;CO 2 the gas product flows to the top of the alcohol washing tower 5 and is finally discharged from the top of the tower, and part of the gas product is directly recovered from a gas-phase product outlet to obtain CO 2 The other part of the gas product is condensed and cooled by the circulating refrigerant sent by the carbon dioxide liquefaction condenser 9 and the refrigerant compressor 14 to obtain cooling liquid; meanwhile, the gas in the alcohol washing tower 5 and the carbon dioxide refluxed from the carbon dioxide product tower 10 carry out mass transfer, heavy components continuously move downwards to the bottom of the alcohol washing tower 5, and CO 2 Primarily purifying and enriching the gas;
in the step 2), the refrigerant cycle process is that the gaseous refrigerant added from the outside is compressed by the refrigerant compressor 14, then is subjected to heat exchange and temperature reduction through the evaporator reboiler 6, is subjected to secondary temperature reduction through the refrigerant condenser 7 to form liquid refrigerant, flows into the refrigerant storage tank 8, is heated by the carbon dioxide liquefaction condenser 9 to become gaseous refrigerant, and returns to the refrigerant compressor 14 again for cycle;
in the step 3), the cooling liquid enters the carbon dioxide product tower 10 mainly for removing light components, and the light components and CO are obtained by separating the cooling liquid 2 The liquid product, the light component deep condenser 11 generates condensate and tail gas (namely noncondensable gas), the tail gas is directly collected and recycled, the condensate returns to the carbon dioxide product tower 10 to continuously condense and separate CO 2 A liquid product; CO2 2 The liquid product flows out from the bottom of the carbon dioxide product tower 10 and is divided into two paths, and the first path directly recovers liquid CO from a liquid-phase product outlet 2 The second path of the product returns to the right upper tower side of the alcohol washing tower 5 through the carbon dioxide reflux pump 13 to transfer mass with the alcohol washing tower 5, thereby realizing CO 2 And (4) primarily purifying and enriching gas products.
In the embodiment, the sulfur-rich gas and two different states of CO are recovered from the sulfur-rich methanol absorbed by the evaporation tower 1, the alcohol washing tower 5, the carbon dioxide product tower 10 and the refrigerant circulation 2 The purity of the product, namely the carbon dioxide product of the sulfur-rich methanol production liquid can be more than 99.5 percent; CO2 2 The purity of the product is lower than that of the sulfur-rich methanol raw material; and the refrigerant circulates in the loop in a gas-liquid mode, so that the heat exchange and the cold exchange can be realized, and the two CO in different states can be regulated 2 Product quality, simplified CO 2 The treatment process saves time and has low energy consumption; this is achieved byIn addition, the production process of the embodiment can be matched with methanol washing, is suitable for large-scale production and has low energy consumption.
In conclusion, in the invention, the carbon dioxide produced by the medium-pressure region thermal method greatly reduces the regeneration energy consumption of the carbon dioxide in the low-pressure region, the same refrigerant is used for heat supply and cold supply, the refrigeration medium is saved, the treatment process is simplified, and the CO in different states is adjusted by mutually changing the gasified refrigerant and the liquid refrigerant 2 The quality of the product can be matched with a methanol washing process, and the method is suitable for large-scale production and low in energy consumption.
Claims (9)
1. A system for generating gas and liquid carbon dioxide by washing methanol is characterized by comprising an evaporation tower (1), an alcohol washing tower reboiler (2), an alcohol washing tower (5), a carbon dioxide liquefaction condenser (9), a carbon dioxide product tower (10) and a refrigerant compressor (14); the evaporation tower (1), the alcohol washing tower reboiler (2), the alcohol washing tower (5), the carbon dioxide liquefaction condenser (9) and the carbon dioxide product tower (10) are communicated in sequence; the alcohol washing tower (5) is respectively communicated with the evaporation tower (1) and the alcohol washing tower reboiler (2); the carbon dioxide product tower (10) is communicated with the alcohol washing tower (5); the evaporation tower (1) is provided with a raw material inlet; a gas-phase product outlet is arranged on the alcohol washing tower (5); a liquid-phase product outlet is arranged on the carbon dioxide product tower (10);
the system for generating the gas and the liquid carbon dioxide by methanol washing also comprises a refrigerant condenser (7) and a refrigerant storage tank (8); the refrigerant compressor (14) returns to the refrigerant compressor (14) to form a circulation loop after sequentially passing through the refrigerant condenser (7), the refrigerant storage tank (8) and the carbon dioxide liquefaction condenser (9).
2. The system for generating gas and liquid carbon dioxide by methanol washing as claimed in claim 1, further comprising an evaporation tower reboiler (6) arranged between the refrigerant compressor (14) and the refrigerant condenser (7); and two ends of the evaporation tower reboiler (6) are respectively communicated with the evaporation tower (1).
3. The system for producing gas and liquid carbon dioxide by methanol scrubbing according to claim 2, further comprising a condensate separator (3) and a gas cooler (4); the reboiler (2) of the alcohol washing tower is communicated with the alcohol washing tower (5) through a condensate separator (3) and a gas cooler (4) in sequence; the condensate separator (3) is communicated with the evaporation tower (1).
4. The system for producing gas and liquid carbon dioxide by methanol scrubbing according to claim 3, further comprising a raw material preheater (15) communicated with the raw material inlet; the raw material preheater (15) is also communicated with the evaporation tower (1).
5. The system for producing gas and liquid carbon dioxide by methanol scrubbing of claim 4, further comprising a reboiler (12) in communication with the carbon dioxide product column (10).
6. A method for producing gas and liquid carbon dioxide by methanol scrubbing based on the system for producing gas and liquid carbon dioxide by methanol scrubbing of claim 4 or 5, characterized in that: the method comprises the following steps:
1) The raw material enters an evaporation tower (1) and is evaporated under the pressure of 1.2-2.0 MP and the temperature of minus 10-45 ℃, the resolved gas phase in the raw material rises, and the liquid phase falls down to form a gas phase at the top of the tower and a liquid phase at the bottom of the tower; the liquid phase at the bottom of the tower is subjected to heat compensation by an evaporation tower reboiler (6), then the analyzed gas phase rises to the evaporation tower (1), the gas phase at the top of the tower is condensed and separated by an alcohol washing tower reboiler (2) to form liquid and gas, the liquid flows back to the evaporation tower (1), and the gas enters an alcohol washing tower (5);
2) The gas is rectified to generate CO at the temperature of minus 25 to minus 38 ℃ through an alcohol washing tower (5) 2 Gas products and bottom liquid of an alcohol washing tower; after the bottom liquid of the alcohol washing tower is subjected to heat supplementing and temperature rising by an alcohol washing tower reboiler (2), partial vaporization is carried out to maintain rectification of ascending gas, and the unvaporized part reflows to the top of the evaporation tower (1) for mass transfer; the gas entering the alcohol washing tower (5) is also simultaneously mixed with CO refluxed from the carbon dioxide product tower (10) 2 The liquid product is subjected to mass transfer, heavy components move downwards, and CO 2 And light components of low boiling point, CO 2 Finishing primary purification of the gas; CO2 2 The gas product rises to the top of the alcohol washing tower (5), one part of the gas product is directly output as the product, the other part of the gas product is condensed by a carbon dioxide liquefaction condenser (9), exchanges heat with a circulating refrigerant sent by a refrigerant storage tank (8) and is condensed, and then the condensed gas enters a carbon dioxide product tower (10);
3) In a carbon dioxide product column (10), condensed CO 2 Separating light components and CO from the gas product 2 Liquid products, light components rise to the top of the carbon dioxide product tower (10) and are cooled by a deep condenser (11) to obtain condensate and tail gas, the tail gas is collected and recycled, and the condensate flows back to the carbon dioxide product tower (10) for mass transfer; CO2 2 The liquid product descends to the bottom of the carbon dioxide product tower (10), most of CO 2 The liquid product is directly output as a product, and a small part of CO is directly output 2 The liquid product flows back to the alcohol washing tower (5) for mass transfer.
7. The method for producing gas and liquid carbon dioxide by methanol washing according to claim 6, characterized in that: the raw material is carbon-rich methanol after methanol washing medium-pressure flash evaporation or sulfur-rich methanol after methanol washing medium-pressure flash evaporation.
8. The method for producing gas and liquid carbon dioxide by methanol washing according to claim 7, characterized in that: when the raw material is the sulfur-rich methanol after methanol washing medium-pressure flash evaporation, in the step 1), sulfur-rich gas is generated after rectification in the alcohol washing tower (5) and is directly recovered from the tower side of the alcohol washing tower (5).
9. The method for producing gas and liquid carbon dioxide by methanol scrubbing according to claim 6, wherein: in the step 2), the refrigerant cycle process is that gaseous refrigerant is compressed by a refrigerant compressor (14), then is subjected to heat exchange and temperature reduction by an evaporation tower reboiler (6), is subjected to secondary temperature reduction and condensation by a refrigerant condenser (7) to form liquid refrigerant, enters a refrigerant storage tank (8) for pressure reduction, is heated by a carbon dioxide liquefaction condenser (9) to become gas phase, and returns to the refrigerant compressor (14) again to form cycle; the gaseous refrigerant is a gas-phase refrigerant added from the outside or circulated in the system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111295451.9A CN113896198B (en) | 2021-11-03 | 2021-11-03 | System and method for generating gas and liquid carbon dioxide by methanol washing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111295451.9A CN113896198B (en) | 2021-11-03 | 2021-11-03 | System and method for generating gas and liquid carbon dioxide by methanol washing |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113896198A CN113896198A (en) | 2022-01-07 |
| CN113896198B true CN113896198B (en) | 2022-11-25 |
Family
ID=79028371
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111295451.9A Active CN113896198B (en) | 2021-11-03 | 2021-11-03 | System and method for generating gas and liquid carbon dioxide by methanol washing |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113896198B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104208978A (en) * | 2014-08-28 | 2014-12-17 | 崔静思 | Equipment and method for gas purification |
| CN110217794A (en) * | 2019-05-09 | 2019-09-10 | 上海启元空分技术发展股份有限公司 | A kind of production method and its process units of high-purity carbon dioxide |
| CN111977654A (en) * | 2020-10-21 | 2020-11-24 | 重庆瑞信气体有限公司 | CO recovery in low-temperature methanol washing section2And process thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10254042B2 (en) * | 2013-10-25 | 2019-04-09 | Air Products And Chemicals, Inc. | Purification of carbon dioxide |
-
2021
- 2021-11-03 CN CN202111295451.9A patent/CN113896198B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104208978A (en) * | 2014-08-28 | 2014-12-17 | 崔静思 | Equipment and method for gas purification |
| CN110217794A (en) * | 2019-05-09 | 2019-09-10 | 上海启元空分技术发展股份有限公司 | A kind of production method and its process units of high-purity carbon dioxide |
| CN111977654A (en) * | 2020-10-21 | 2020-11-24 | 重庆瑞信气体有限公司 | CO recovery in low-temperature methanol washing section2And process thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113896198A (en) | 2022-01-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4160810A (en) | Removal of acid gases from hot gas mixtures | |
| CN109999618B (en) | System and method for separating carbon dioxide from medium-high pressure gas source | |
| US20140374105A1 (en) | Process for the removal of carbon dioxide from a gas | |
| CN103435517A (en) | Yield-increasing and energy-saving technology of carbon dioxide stripping urea and equipment of carbon dioxide stripping urea | |
| CN101643220A (en) | Natural gas type synthesis ammonia energy-saving and emission-reduction technology | |
| CN111238166A (en) | Refrigeration cycle system and method in carbon dioxide rectification separation process | |
| CN102977960A (en) | Process for co-producing and synthetic natural gas and food-grade carbon dioxide by using calcium carbide furnace gas | |
| CN110207460A (en) | A kind of recyclable device and its recovery method of integrated High Purity Nitrogen and argon gas | |
| CN111807981A (en) | Method for recovering DMF (dimethyl formamide) from trichloroethane | |
| US4149857A (en) | Process for the two-stage separation of ammonia | |
| CN110803689A (en) | Argon recovery method and device for removing carbon monoxide and integrating high-purity nitrogen by rectification method | |
| CN214114973U (en) | CO conversion condensate refining process system | |
| CN113896198B (en) | System and method for generating gas and liquid carbon dioxide by methanol washing | |
| CN210410096U (en) | Separation system for carbon dioxide in medium-high pressure gas source | |
| CN212842469U (en) | Single-tower cryogenic rectification argon recovery system with argon circulation and hydrogen circulation | |
| CN213335168U (en) | Refrigeration cycle system in carbon dioxide rectification separation process | |
| CN211290725U (en) | Recovery unit of integrated high-purity nitrogen and argon gas | |
| CN114100167A (en) | Energy-saving maleic anhydride absorption deep analysis refining process | |
| CN111637685A (en) | Single-tower cryogenic rectification argon recovery system and method with argon circulation and hydrogen circulation | |
| CN113563148A (en) | Coal-based natural gas and methanol poly-generation system and method integrating waste heat refrigeration | |
| CN111637684A (en) | Single-tower cryogenic rectification argon recovery system with circulation and method | |
| CN218166519U (en) | Purification and quality improvement system for residual ammonia water and ammonia distillation strong ammonia water | |
| CN219815326U (en) | Energy-saving light tower removing device | |
| EP3964769A1 (en) | Aqua-ammonia absorption refrigeration process and method of revamping | |
| CN220827260U (en) | Coal gasification ammonia-containing wastewater high-efficiency comprehensive recovery device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |