CN104654739A

CN104654739A - Device and method for preparing food-grade liquid carbon dioxide by rectification and purification with double towers

Info

Publication number: CN104654739A
Application number: CN201510068104.0A
Authority: CN
Inventors: 陈剑军; 张亚清; 闫红伟; 吕书山; 银延蛟
Original assignee: HENAN XINLIANXIN SHENLENG ENERGY Co Ltd
Current assignee: HENAN XINLIANXIN SHENLENG ENERGY Co Ltd
Priority date: 2015-02-02
Filing date: 2015-02-02
Publication date: 2015-05-27
Anticipated expiration: 2035-02-02
Also published as: CN104654739B

Abstract

The invention belongs to a device and a method for preparing food-grade liquid carbon dioxide by rectification and purification with double towers. The structure of the device is as follows: an outlet of a gas inlet buffer tank is connected with an inlet of a feed gas four-stage compressor, the outlet of the feed gas four-stage compressor is connected with a feed gas inlet formed in the middle lower part of a first rectification tower by a first re-boiler, a liquid phase outlet formed in the bottom of the first rectification tower is connected with a collector, a gas phase outlet formed in the top of the first rectification tower is connected with a gas phase inlet of a tower top condenser, the liquid phase outlet of the tower top condenser is connected with a liquid phase inlet formed in the upper part of the first rectification tower, a first tee is arranged on a pipeline between the liquid phase outlet of the tower top condenser and the liquid phase inlet of the upper part of the first rectification tower, a third end of the first tee is connected with a liquid inlet formed in the middle of a second rectification tower, a liquid phase outlet formed in the bottom of the second rectification tower is connected with a liquid inlet of a first heat exchanger by a pipeline, and a liquid outlet of the first heat exchanger is connected with a carbon dioxide storage tank. The device and the method have the following advantages of simple technological process, easy and convenient operation, stable running and low energy consumption.

Description

Utilize two-tower rectification to purify and produce the apparatus and method of food-class liquid CO 2

Technical field

The invention belongs to carbon dioxide production technical field, be specifically related to a kind of apparatus and method utilizing two-tower rectification purification to produce food-class liquid CO 2.

Background technology

The production of traditional food grade carbon-dioxide generally adopts molecular sieve dehydration dealcoholysis and Production by Catalytic Combustion Process to take off hydrocarbon device and technique thereof; Wherein, need a large amount of heats for thermal regeneration gas in the molecular sieve dehydration dealcoholysis stage, energy consumption is higher, and dehydration dealcoholysis then needs successively through release, regeneration, cold blowing, all press, and operating process is complicated; Need the equipment dropped into containing sequencing valve, adsorbent, adsorption tower, electric heater etc. one-time investment is larger; Production by Catalytic Combustion Process takes off the hydrocarbon stage and adopts platinum, palladium series catalyst and patent equipment, and price is higher, and its material needs cold through preheating, heating, de-hydrocarbon, water-cooled and ammonia successively, and energy consumption is higher.Above-mentioned technical process not only brings white elephant to manufacturing enterprise, also for using enterprise to add production cost.

Summary of the invention

The object of the invention is to overcome defect of the prior art, and provide that a kind of flow process is simple, reasonable in design, easy to operate, stable, energy consumption is low and disposable less investment utilize two-tower rectification to purify to produce the apparatus and method of food-class liquid CO 2.

The object of the present invention is achieved like this: comprise air inlet surge tank, the outlet of air inlet surge tank is connected by the import of pipeline with unstripped gas four-stage compressor, the outlet of unstripped gas four-stage compressor is connected by the raw material gas inlet of the first reboiler with the first rectifying column middle and lower part, the liquid-phase outlet of the first rectifier bottoms is connected with collector, the gaseous phase outlet at the first rectifying column top is connected with the gas phase import of overhead condenser, the liquid-phase outlet of overhead condenser is connected by the fluid inlet of pipeline with the first rectifier, pipeline between the liquid-phase outlet of overhead condenser and the fluid inlet of the first rectifier is provided with the first threeway, 3rd end of the first threeway by pipeline successively with the second reboiler, first control valve is connected with inlet in the middle part of Second distillation column, liquid-phase outlet bottom Second distillation column is connected with the inlet of First Heat Exchanger by pipeline, and the liquid outlet of First Heat Exchanger is connected with carbon dioxide storage tank, the gaseous phase outlet at described overhead condenser top is connected with gas-liquid separator with the shell side of the second heat exchanger by the second threeway, liquid-phase outlet bottom gas-liquid separator is connected by the fluid inlet of pipeline with Second distillation column top, the gaseous phase outlet at gas-liquid separator top is connected with the first gas phase import of First Heat Exchanger, and the first gaseous phase outlet of First Heat Exchanger is connected with waste gas header, the gaseous phase outlet at described Second distillation column top is connected with the 3rd end of the second threeway by pipeline, pipeline between described second reboiler and the first control valve is provided with the 3rd threeway, 3rd end of described 3rd threeway is connected with the second gas phase import of First Heat Exchanger with the tube side of the second heat exchanger by the second control valve, and the second gaseous phase outlet of First Heat Exchanger is connected with the two-stage compression air inlet of unstripped gas four-stage compressor by pipeline.

Utilize two-tower rectification to purify and produce a method for food-class liquid CO 2 device, comprise the steps:

Step one: unstripped gas enters the first reboiler import by air inlet surge tank and unstripped gas four-stage compressor, the component of described unstripped gas is: carbon dioxide 95 ~ 99%, water 0.4 ~ 2%, alcohol 0.1 ~ 2%, hydrocarbon 0.1 ~ 1%, temperature is: 10 ~ 40 DEG C, and pressure is: 0.1 ~ 0.2Mpa; Described unstripped gas by the temperature after unstripped gas four-stage compressor 1 is: 90 ~ 120 DEG C, and pressure is 4 ~ 6Mpa;

Step 2: make to enter the first reboiler imported materials gas described in step one and enter in the first rectifying column by the raw material gas inlet of the first reboiler and the first rectifying column middle and lower part; The raw material gas inlet of described first rectifying column middle and lower part goes out unstripped gas temperature and is: 30 ~ 80 DEG C;

Step 3: make to enter described in step 2 unstripped gas in the first rectifying column and overhead condenser and carry out mass-and heat-transfer by the low-boiling point material entering the first rectifying column in the fluid inlet of the first threeway and the first rectifier, high boiling substance after mass-and heat-transfer enters in collector by the liquid-phase outlet of the first rectifier bottoms after condensation, and its low-boiling point material enters in overhead condenser by the gaseous phase outlet at the first rectifying column top and the gas phase import of overhead condenser; High boiling substance component in the described collector entered is: carbon dioxide 30 ~ 35%, alcohol 5 ~ 11%, water 40 ~ 60%, hydro carbons 0.1 ~ 1%, and temperature is: 50 ~ 80 DEG C, and pressure is 4 ~ 6Mpa;

Step 4: make the liquid phase of the low-boiling point material in overhead condenser described in step 3 by the first threeway, the liquid phase of part low-boiling point material enters in the first rectifying column in the fluid inlet of the first rectifier carries out mass-and heat-transfer with the unstripped gas in the first rectifying column, the liquid phase of another part low-boiling point material is divided into two-way, and first via inlet in the middle part of the second reboiler, the 3rd threeway, the first control valve and Second distillation column enters the inside of Second distillation column; Second tunnel second reboiler, the 3rd threeway and the second control valve enter the tube side of the second heat exchanger; The described liquidus temperature entering the low-boiling point material of Second distillation column inside is: 5 ~-10 DEG C, and pressure is 4 ~ 6Mpa, and flow is 748Nm ³/ h; The liquid phase component of low-boiling point material in described rectifying column overhead condenser: carbon dioxide 99.3%, foreign gas 0.7%, temperature is 5 ~-10 DEG C, and pressure is 4.8Mpa; The liquidus temperature entering the low-boiling point material of the second heat exchanger tube pass is :-30 ~-45 DEG C, and pressure is 1.0 ~ 2.0Mpa;

Step 5: the carbon dioxide rich solution that the liquid phase of the low-boiling point material entering Second distillation column inside described in step 4 and the fluid inlet by the liquid-phase outlet bottom gas-liquid separator and Second distillation column top are entered in Second distillation column carries out mass-and heat-transfer, after mass-and heat-transfer, the gas phase of secondary low-boiling point material discharges Second distillation column by the gaseous phase outlet at Second distillation column top, and its secondary high boiling substance enters in carbon dioxide storage tank by the inlet of the liquid-phase outlet bottom Second distillation column, First Heat Exchanger and the liquid outlet of First Heat Exchanger; Liquid-phase outlet secondary high boiling substance component bottom described Second distillation column is: carbon dioxide 99.99%, flow is: 666Nm ³/ h, temperature is :-10 ~-20 DEG C, and pressure is 1.5 ~ 3.0Mpa; The temperature of the secondary high boiling substance of the inlet of described First Heat Exchanger is :-10 ~-20 DEG C, and pressure is: 1.5 ~ 3.0Mpa; The temperature of the liquid outlet secondary high boiling substance of described First Heat Exchanger is :-15 DEG C ~-20 DEG C, pressure is: 1.5 ~ 3.0Mpa; The described secondary high boiling substance entered in carbon dioxide storage tank is food-grade carbon-dioxide, and its carbon dioxide content is 99.99%;

Step 6: make the gas phase of the low-boiling point material in overhead condenser described in step 3 enter in the shell side of the second heat exchanger by overhead condenser gaseous phase outlet and the second threeway, the gas phase of the secondary low-boiling point material of discharging Second distillation column described in step 5 is entered in the shell side of the second heat exchanger by the second threeway, makes the gas phase of the gas phase of the gas phase of low-boiling point material and secondary low-boiling point material in the shell side of the second heat exchanger after mixed heat transfer enter in gas-liquid separator; The gaseous component of the low-boiling point material of described overhead condenser gaseous phase outlet is carbon dioxide 50 ~ 65%, and temperature is: 0 ~-10 DEG C, pressure is: 4.8Mpa; The gaseous component of the secondary low-boiling point material of described Second distillation column is: carbon dioxide 91%, hydrogen 1%, oxygen 2.1%, nitrogen 5.9%, and temperature is: 0 ~-15 DEG C, and pressure is 1.0 ~ 2.5Mpa; Gas temperature in described second heat exchanger shell pass after mixed heat transfer is :-30 DEG C, and pressure is: 1.26Mpa;

Step 7: make the gas phase entered described in step 6 in gas-liquid separator after mixed heat transfer carry out gas-liquid separation, carbon dioxide rich solution after gas-liquid separation enters in Second distillation column by the fluid inlet on the liquid-phase outlet bottom gas-liquid separator and Second distillation column top, and the waste gas after gas-liquid separation enters waste gas header by the first gaseous phase outlet of the gaseous phase outlet at gas-liquid separator top, the first gas phase import of First Heat Exchanger and First Heat Exchanger; Described go out the carbon dioxide rich solution component of liquid-phase outlet bottom gas-liquid separator be: carbon dioxide 80 ~ 90%, temperature is :-10 ~-32 DEG C, and pressure is 1.5 ~ 3.0MPa; Described go out the waste gas component of gaseous phase outlet at gas-liquid separator top be: carbon dioxide 30 ~ 52%, temperature is-10 ~-32 DEG C, and pressure is 1.5 ~ 3.0MPa;

Step 8: make the liquid phase of the low-boiling point material entering the second heat exchanger tube pass described in step 4 be entered the two-stage compression air inlet of unstripped gas four-stage compressor successively by the second gas phase import of the second heat exchanger tube pass, First Heat Exchanger and the second gaseous phase outlet of First Heat Exchanger; The described liquidus temperature entering the low-boiling point material of the two-stage compression air inlet of unstripped gas four-stage compressor is :-14 DEG C, and pressure is 1.0 ~ 2.0Mpa.

Step one: unstripped gas enters the first reboiler import by air inlet surge tank and unstripped gas four-stage compressor, the component of described unstripped gas is: carbon dioxide 98.1%, water 1%, and alcohol 0.4%, hydrocarbon 0.5%, flow is: 770Nm ³/ h, temperature is: 40 DEG C, and pressure is: 0.12Mpa; Described unstripped gas by the temperature after unstripped gas four-stage compressor is: 100 DEG C, and pressure is 4.8Mpa;

Step 2: make to enter the first reboiler imported materials gas described in step one and enter in the first rectifying column by the raw material gas inlet of the first reboiler and the first rectifying column middle and lower part; The raw material gas inlet of described first rectifying column middle and lower part goes out unstripped gas temperature and is: 65 DEG C;

Step 3: make to enter described in step 2 unstripped gas in the first rectifying column and overhead condenser and carry out mass-and heat-transfer by the low-boiling point material entering the first rectifying column in the fluid inlet of the first threeway and the first rectifier, high boiling substance after mass-and heat-transfer enters in collector by the liquid-phase outlet of the first rectifier bottoms after condensation, and its low-boiling point material enters in overhead condenser by the gaseous phase outlet at the first rectifying column top and the gas phase import of overhead condenser; High boiling substance component in the described collector entered is: carbon dioxide 31.8%, alcohol 10.3%, water 57.8%, hydro carbons 0.1%, and temperature is: 69.4 DEG C, and pressure is 4.8Mpa;

Step 4: make the liquid phase of the low-boiling point material in overhead condenser described in step 3 by the first threeway 13, the liquid phase of part low-boiling point material enters in the first rectifying column in the fluid inlet of the first rectifier carries out mass-and heat-transfer with the unstripped gas in the first rectifying column, the liquid phase of another part low-boiling point material is divided into two-way, and first via inlet in the middle part of the second reboiler, the 3rd threeway, the first control valve and Second distillation column enters the inside of Second distillation column; Second tunnel second reboiler, the 3rd threeway and the second control valve enter the tube side of the second heat exchanger; The described liquidus temperature entering the low-boiling point material of Second distillation column inside is :-10 DEG C, and pressure is 4.8Mpa, and flow is 748Nm ³/ h; The liquid phase component of low-boiling point material in described rectifying column overhead condenser: carbon dioxide 99.3%, foreign gas 0.7%, temperature is-5 DEG C, and pressure is 4.8Mpa; The liquidus temperature entering the low-boiling point material of the second heat exchanger 6 tube side is :-34.5 DEG C, and pressure is 1.26Mpa;

Step 5: the carbon dioxide rich solution that the liquid phase of the low-boiling point material entering Second distillation column inside described in step 4 and the fluid inlet by the liquid-phase outlet bottom gas-liquid separator 7 and Second distillation column top are entered in Second distillation column carries out mass-and heat-transfer, after mass-and heat-transfer, the gas phase of secondary low-boiling point material discharges Second distillation column by the gaseous phase outlet at Second distillation column top, and its secondary high boiling substance enters in carbon dioxide storage tank by the inlet of the liquid-phase outlet bottom Second distillation column, First Heat Exchanger and the liquid outlet of First Heat Exchanger; Liquid-phase outlet secondary high boiling substance component bottom described Second distillation column is: carbon dioxide 99.99%, flow is: 666Nm ³/ h, temperature is :-12.1 DEG C, and pressure is 2.5Mpa; The temperature of the secondary high boiling substance of the inlet of described First Heat Exchanger is :-10 ~-20 DEG C, and pressure is: 2.5Mpa; The temperature of the liquid outlet secondary high boiling substance of described First Heat Exchanger is :-15 DEG C, pressure is: 2.5Mpa; The described secondary high boiling substance entered in carbon dioxide storage tank is food-grade carbon-dioxide, and its carbon dioxide content is 99.99%;

Step 6: make the gas phase of the low-boiling point material in overhead condenser described in step 3 enter in the shell side of the second heat exchanger by overhead condenser gaseous phase outlet and the second threeway, the gas phase of the secondary low-boiling point material of discharging Second distillation column described in step 5 is entered in the shell side of the second heat exchanger by the second threeway, makes the gas phase of the gas phase of the gas phase of low-boiling point material and secondary low-boiling point material in the shell side of the second heat exchanger after mixed heat transfer enter in gas-liquid separator; The gaseous component of the low-boiling point material of described overhead condenser gaseous phase outlet is carbon dioxide 63.1%, and temperature is :-5 DEG C, and pressure is: 4.8Mpa; The gaseous component of the secondary low-boiling point material of described Second distillation column is: carbon dioxide 91%, hydrogen 1%, oxygen 2.1%, nitrogen 5.9%, and temperature is :-15.2 DEG C, and pressure is 2.5Mpa; Gas temperature in described second heat exchanger shell pass after mixed heat transfer is :-30 DEG C, and pressure is: 1.26Mpa;

Step 7: make the gas phase entered described in step 6 in gas-liquid separator after mixed heat transfer carry out gas-liquid separation, carbon dioxide rich solution after gas-liquid separation enters in Second distillation column by the fluid inlet on the liquid-phase outlet bottom gas-liquid separator and Second distillation column top, and the waste gas after gas-liquid separation enters waste gas header by the first gaseous phase outlet of the gaseous phase outlet at gas-liquid separator top, the first gas phase import of First Heat Exchanger and First Heat Exchanger; Described go out the carbon dioxide rich solution component of liquid-phase outlet bottom gas-liquid separator be: carbon dioxide 88.2%, temperature is :-32 DEG C, and pressure is 2.5MPa; Described go out the waste gas component of gaseous phase outlet at gas-liquid separator top be: carbon dioxide 43.8%, temperature is-32 DEG C, and pressure is 2.5MPa;

Step 8: make the liquid phase of the low-boiling point material entering the second heat exchanger tube pass described in step 4 be entered the two-stage compression air inlet of unstripped gas four-stage compressor successively by the second gas phase import of the second heat exchanger tube pass, First Heat Exchanger and the second gaseous phase outlet of First Heat Exchanger; The described liquidus temperature entering the low-boiling point material of the two-stage compression air inlet of unstripped gas four-stage compressor is :-14 DEG C, and pressure is 1.26Mpa.

With noble metal (Palladium molybdenum in traditional food grade carbon-dioxide production process) catalyst is for catalyst, and pass into oxygen, under 425 DEG C of conditions, benzene, hydrocarbon compound are oxidized to carbon dioxide and water, whole process must be heated to 425 DEG C through electric heater.Food-grade carbon-dioxide is produced after the incoagulable gas such as the gas after catalytic oxidation, through again cooling, enters cryogenic system and carries out cryogenic rectification after molecular sieve drying, removing oxygen.The present invention overcomes the employing of above-mentioned traditional concept, by compressor, unstripped gas is pressurized to 4.8MPa, unstripped gas after pressurization regulates its temperature by the water-cooled of additional multiple line, pass into the first reboiler of the first rectifier bottoms, maintain rectifying column column bottom temperature between 50 ~ 75 DEG C by multiple line valve opening.Enter in the middle part of the first rectifying column from the first reboiler unstripped gas out, high boiling substance discharges system from tower reactor, overhead condensation liquid partial reflux, major part condensed fluid to enter to bottom Second distillation column the second reboiler for rectifying provides cold, then be divided into two strands, one throttling enters Second distillation column as after 3.5MPa, another meropodium flow to 1.2MPa for the second heat exchanger cold is provided after enter First Heat Exchanger, enter compressor secondary inlet after recovery section cold.The second heat exchanger shell pass is entered after Second distillation column top fixed gas and the first rectifying column top fixed gas bout, gas-liquid separator is entered after partial liquefaction, liquid-phase reflux is in Second distillation column, and gas-liquid separator top fixed gas enters First Heat Exchanger, discharges system after reclaiming cold; Bottom Second distillation column high-pureness carbon dioxide enter First Heat Exchanger cross cold after enter in carbon dioxide storage tank, there is technological process simple, easy and simple to handle, the advantage of stable and low energy consumption.

Accompanying drawing explanation

Fig. 1 is structural representation of the present invention.

Detailed description of the invention

As shown in Figure 1, the present invention is for comprising air inlet surge tank 22, air inlet surge tank 22 is exported and is connected by the import of pipeline with unstripped gas four-stage compressor 1, the outlet of unstripped gas four-stage compressor 1 is connected by the raw material gas inlet of the first reboiler 2 with the first rectifying column 3 middle and lower part, liquid-phase outlet bottom first rectifying column 3 is connected with collector 4, the gaseous phase outlet at the first rectifying column 3 top is connected with the gas phase import of overhead condenser 5, the liquid-phase outlet of overhead condenser 5 is connected by the fluid inlet of pipeline with the first rectifying column 3 top, pipeline between the liquid-phase outlet of overhead condenser 5 and the fluid inlet on the first rectifying column 3 top is provided with the first threeway 13, 3rd end of the first threeway 13 by pipeline successively with the second reboiler 8, first control valve 10 is connected with inlet in the middle part of Second distillation column 9, liquid-phase outlet bottom Second distillation column 9 is connected by the inlet of pipeline with First Heat Exchanger 12, and the liquid outlet of First Heat Exchanger 12 is connected with carbon dioxide storage tank 16, the gaseous phase outlet at described overhead condenser 5 top is connected with gas-liquid separator 7 with the shell side of the second heat exchanger 6 by the second threeway 14, liquid-phase outlet bottom gas-liquid separator 7 is connected by the fluid inlet of pipeline with Second distillation column 9 top, the gaseous phase outlet at gas-liquid separator 7 top is connected with the first gas phase import 18 of First Heat Exchanger 12, and the first gaseous phase outlet 19 of First Heat Exchanger 12 is connected with waste gas header 17, the gaseous phase outlet at described Second distillation column 9 top is connected with the 3rd end of the second threeway 14 by pipeline, pipeline between described second reboiler 8 and the first control valve 10 is provided with the 3rd threeway 15,3rd end of described 3rd threeway 15 is connected with the second gas phase import 20 of First Heat Exchanger 12 with the tube side of the second heat exchanger 6 by the second control valve 11, and the second gaseous phase outlet 21 of First Heat Exchanger 12 is connected with the two-stage compression air inlet of unstripped gas four-stage compressor 1 by pipeline.

Step one: unstripped gas enters the first reboiler 2 import by air inlet surge tank 22 and unstripped gas four-stage compressor 1, the component of described unstripped gas is: carbon dioxide 95 ~ 99%, water 0.4 ~ 2%, alcohol 0.1 ~ 2%, hydrocarbon 0.1 ~ 1%, temperature is: 10 ~ 40 DEG C, and pressure is: 0.1 ~ 0.2Mpa; Described unstripped gas by the temperature after unstripped gas four-stage compressor 1 is: 90 ~ 120 DEG C, and pressure is 4 ~ 6Mpa;

Step 2: make to enter the first reboiler 2 imported materials gas described in step one and enter in the first rectifying column 3 by the raw material gas inlet of the first reboiler 2 and the first rectifying column 3 middle and lower part; The raw material gas inlet of described first rectifying column 3 middle and lower part goes out unstripped gas temperature and is: 30 ~ 80 DEG C;

Step 3: make to enter described in step 2 unstripped gas in the first rectifying column 3 and overhead condenser 5 and carry out mass-and heat-transfer by the low-boiling point material entering the first rectifying column 3 in the fluid inlet on the first threeway 13 and the first rectifying column 3 top, high boiling substance after mass-and heat-transfer enters in collector 4 by the liquid-phase outlet bottom the first rectifying column 3 after condensation, and its low-boiling point material enters in overhead condenser 5 by the gaseous phase outlet at the first rectifying column 3 top and the gas phase import of overhead condenser 5; High boiling substance component in the described collector 4 entered is: carbon dioxide 30 ~ 35%, alcohol 5 ~ 11%, water 40 ~ 60%, hydro carbons 0.1 ~ 1%, and temperature is: 50 ~ 80 DEG C, and pressure is 4 ~ 6Mpa;

Step 4: make the liquid phase of the low-boiling point material in overhead condenser 5 described in step 3 by the first threeway 13, the liquid phase of part low-boiling point material enters in the first rectifying column 3 in the fluid inlet on the first rectifying column 3 top carries out mass-and heat-transfer with the unstripped gas in the first rectifying column 3, the liquid phase of another part low-boiling point material is divided into two-way, and first via inlet in the middle part of the second reboiler 8, the 3rd threeway 15, first control valve 10 and Second distillation column 9 enters the inside of Second distillation column 9; Second tunnel second reboiler the 8, the 3rd threeway 15 and the second control valve 11 enter the tube side of the second heat exchanger 6; The described liquidus temperature entering the low-boiling point material of Second distillation column 9 inside is: 5 ~-10 DEG C, and pressure is 4 ~ 6Mpa, and flow is 748Nm ³/ h; The liquid phase component of low-boiling point material in described rectifying column overhead condenser 5: carbon dioxide 99.3%, foreign gas 0.7%, temperature is 5 ~-10 DEG C, and pressure is 4.8Mpa; The liquidus temperature entering the low-boiling point material of the second heat exchanger 6 tube side is :-30 ~-45 DEG C, and pressure is 1.0 ~ 2.0Mpa;

Step 5: the carbon dioxide rich solution that the liquid phase of the low-boiling point material entering Second distillation column 9 inside described in step 4 and the fluid inlet by the liquid-phase outlet bottom gas-liquid separator 7 and Second distillation column 9 top are entered in Second distillation column 9 carries out mass-and heat-transfer, after mass-and heat-transfer, the gas phase of secondary low-boiling point material discharges Second distillation column 9 by the gaseous phase outlet at Second distillation column 9 top, and its secondary high boiling substance enters in carbon dioxide storage tank 16 by the inlet of the liquid-phase outlet bottom Second distillation column 9, First Heat Exchanger 12 and the liquid outlet of First Heat Exchanger 12; Liquid-phase outlet secondary high boiling substance component bottom described Second distillation column 9 is: carbon dioxide 99.99%, flow is: 666Nm ³/ h, temperature is :-10 ~-20 DEG C, and pressure is 1.5 ~ 3.0Mpa; The temperature of the secondary high boiling substance of the inlet of described First Heat Exchanger 12 is :-10 ~-20 DEG C, and pressure is: 1.5 ~ 3.0Mpa; The temperature of the liquid outlet secondary high boiling substance of described First Heat Exchanger 12 is :-15 DEG C ~-20 DEG C, pressure is: 1.5 ~ 3.0Mpa; The described secondary high boiling substance entered in carbon dioxide storage tank 16 is food-grade carbon-dioxide, and its carbon dioxide content is 99.99%;

Step 6: make the gas phase of the low-boiling point material in overhead condenser 5 described in step 3 enter in the shell side of the second heat exchanger 6 by overhead condenser 5 gaseous phase outlet and the second threeway 14, the gas phase of the secondary low-boiling point material of discharging Second distillation column 9 described in step 5 is entered in the shell side of the second heat exchanger 6 by the second threeway 14, makes the gas phase of the gas phase of the gas phase of low-boiling point material and secondary low-boiling point material in the shell side of the second heat exchanger 6 after mixed heat transfer enter in gas-liquid separator 7; The gaseous component of the low-boiling point material of described overhead condenser 5 gaseous phase outlet is carbon dioxide 50 ~ 65%, and temperature is: 0 ~-10 DEG C, pressure is: 4.8Mpa; The gaseous component of the secondary low-boiling point material of described Second distillation column 9 is: carbon dioxide 91%, hydrogen 1%, oxygen 2.1%, nitrogen 5.9%, and temperature is: 0 ~-15 DEG C, and pressure is 1.0 ~ 2.5Mpa; Gas temperature in described second heat exchanger 6 shell side after mixed heat transfer is :-30 DEG C, pressure is: 1.26Mpa;

Step 7: make the gas phase entered described in step 6 in gas-liquid separator 7 after mixed heat transfer carry out gas-liquid separation, carbon dioxide rich solution after gas-liquid separation enters in Second distillation column 9 by the fluid inlet on the liquid-phase outlet bottom gas-liquid separator 7 and Second distillation column 9 top, and the waste gas after gas-liquid separation enters waste gas header 17 by the first gaseous phase outlet 19 of the gaseous phase outlet at gas-liquid separator 7 top, the first gas phase import 18 of First Heat Exchanger 12 and First Heat Exchanger 12; Described go out the carbon dioxide rich solution component of liquid-phase outlet bottom gas-liquid separator 7 be: carbon dioxide 80 ~ 90%, temperature is :-10 ~-32 DEG C, and pressure is 1.5 ~ 3.0MPa; Described go out the waste gas component of gaseous phase outlet at gas-liquid separator 7 top be: carbon dioxide 30 ~ 52%, temperature is-10 ~-32 DEG C, and pressure is 1.5 ~ 3.0MPa;

Step 8: make the liquid phase of the low-boiling point material entering the second heat exchanger 6 tube side described in step 4 be entered the two-stage compression air inlet of unstripped gas four-stage compressor 1 successively by the second gas phase import 20 of the second heat exchanger 6 tube side, First Heat Exchanger 12 and the second gaseous phase outlet 21 of First Heat Exchanger 12; The described liquidus temperature entering the low-boiling point material of the two-stage compression air inlet of unstripped gas four-stage compressor 1 is :-14 DEG C, and pressure is 1.0 ~ 2.0Mpa.

Now in conjunction with specific embodiments the present invention is further described.Concrete embodiment is as follows:

Embodiment one

Step one: unstripped gas enters the first reboiler 2 import by air inlet surge tank 22 and unstripped gas four-stage compressor 1, and the component of described unstripped gas is: carbon dioxide 95%, water 2%, alcohol 2%, hydrocarbon 1%, and temperature is: 10 DEG C, and pressure is: 0.1Mpa; Described unstripped gas by the temperature after unstripped gas four-stage compressor 1 is: 90 DEG C, and pressure is 4Mpa;

Step 2: make to enter the first reboiler 2 imported materials gas described in step one and enter in the first rectifying column 3 by the raw material gas inlet of the first reboiler 2 and the first rectifying column 3 middle and lower part; The raw material gas inlet of described first rectifying column 3 middle and lower part goes out unstripped gas temperature and is: 30 DEG C;

Step 3: make to enter described in step 2 unstripped gas in the first rectifying column 3 and overhead condenser 5 and carry out mass-and heat-transfer by the low-boiling point material entering the first rectifying column 3 in the fluid inlet on the first threeway 13 and the first rectifying column 3 top, high boiling substance after mass-and heat-transfer enters in collector 4 by the liquid-phase outlet bottom the first rectifying column 3 after condensation, and its low-boiling point material enters in overhead condenser 5 by the gaseous phase outlet at the first rectifying column 3 top and the gas phase import of overhead condenser 5; High boiling substance component in the described collector 4 entered is: carbon dioxide 30%, alcohol 10.5%, water 59%, hydro carbons 0.5%, and temperature is: 50 DEG C, and pressure is 4Mpa;

Step 4: make the liquid phase of the low-boiling point material in overhead condenser 5 described in step 3 by the first threeway 13, the liquid phase of part low-boiling point material enters in the first rectifying column 3 in the fluid inlet on the first rectifying column 3 top carries out mass-and heat-transfer with the unstripped gas in the first rectifying column 3, the liquid phase of another part low-boiling point material is divided into two-way, and first via inlet in the middle part of the second reboiler 8, the 3rd threeway 15, first control valve 10 and Second distillation column 9 enters the inside of Second distillation column 9; Second tunnel second reboiler the 8, the 3rd threeway 15 and the second control valve 11 enter the tube side of the second heat exchanger 6; The described liquidus temperature entering the low-boiling point material of Second distillation column 9 inside is :-10 DEG C, and pressure is 4Mpa, and flow is 748Nm ³/ h; The liquid phase component of low-boiling point material in described rectifying column overhead condenser 5: carbon dioxide 99.3%, foreign gas 0.7%, temperature is-10 DEG C, and pressure is 4.8Mpa; The liquidus temperature entering the low-boiling point material of the second heat exchanger 6 tube side is :-45 DEG C, and pressure is 1.0Mpa;

Step 5: the carbon dioxide rich solution that the liquid phase of the low-boiling point material entering Second distillation column 9 inside described in step 4 and the fluid inlet by the liquid-phase outlet bottom gas-liquid separator 7 and Second distillation column 9 top are entered in Second distillation column 9 carries out mass-and heat-transfer, after mass-and heat-transfer, the gas phase of secondary low-boiling point material discharges Second distillation column 9 by the gaseous phase outlet at Second distillation column 9 top, and its secondary high boiling substance enters in carbon dioxide storage tank 16 by the inlet of the liquid-phase outlet bottom Second distillation column 9, First Heat Exchanger 12 and the liquid outlet of First Heat Exchanger 12; Liquid-phase outlet secondary high boiling substance component bottom described Second distillation column 9 is: carbon dioxide 99.99%, flow is: 666Nm ³/ h, temperature is :-20 DEG C, and pressure is 1.5Mpa; The temperature of the secondary high boiling substance of the inlet of described First Heat Exchanger 12 is :-10 ~-20 DEG C, and pressure is: 1.5Mpa; The temperature of the liquid outlet secondary high boiling substance of described First Heat Exchanger 12 is :-15 DEG C, pressure is: 1.5Mpa; The described secondary high boiling substance entered in carbon dioxide storage tank 16 is food-grade carbon-dioxide, and its carbon dioxide content is 99.99%;

Step 6: make the gas phase of the low-boiling point material in overhead condenser 5 described in step 3 enter in the shell side of the second heat exchanger 6 by overhead condenser 5 gaseous phase outlet and the second threeway 14, the gas phase of the secondary low-boiling point material of discharging Second distillation column 9 described in step 5 is entered in the shell side of the second heat exchanger 6 by the second threeway 14, makes the gas phase of the gas phase of the gas phase of low-boiling point material and secondary low-boiling point material in the shell side of the second heat exchanger 6 after mixed heat transfer enter in gas-liquid separator 7; The gaseous component of the low-boiling point material of described overhead condenser 5 gaseous phase outlet is carbon dioxide 50%, and temperature is :-10 DEG C, and pressure is: 4.8Mpa; The gaseous component of the secondary low-boiling point material of described Second distillation column 9 is: carbon dioxide 91%, hydrogen 1%, oxygen 2.1%, nitrogen 5.9%, and temperature is :-15 DEG C, and pressure is 1.0Mpa; Gas temperature in described second heat exchanger 6 shell side after mixed heat transfer is :-30 DEG C, pressure is: 1.26Mpa;

Step 7: make the gas phase entered described in step 6 in gas-liquid separator 7 after mixed heat transfer carry out gas-liquid separation, carbon dioxide rich solution after gas-liquid separation enters in Second distillation column 9 by the fluid inlet on the liquid-phase outlet bottom gas-liquid separator 7 and Second distillation column 9 top, and the waste gas after gas-liquid separation enters waste gas header 17 by the first gaseous phase outlet 19 of the gaseous phase outlet at gas-liquid separator 7 top, the first gas phase import 18 of First Heat Exchanger 12 and First Heat Exchanger 12; Described go out the carbon dioxide rich solution component of liquid-phase outlet bottom gas-liquid separator 7 be: carbon dioxide 80%, temperature is :-32 DEG C, and pressure is 1.5MPa; Described go out the waste gas component of gaseous phase outlet at gas-liquid separator 7 top be: carbon dioxide 30%, temperature is-32 DEG C, and pressure is 1.5MPa;

Step 8: make the liquid phase of the low-boiling point material entering the second heat exchanger 6 tube side described in step 4 be entered the two-stage compression air inlet of unstripped gas four-stage compressor 1 successively by the second gas phase import 20 of the second heat exchanger 6 tube side, First Heat Exchanger 12 and the second gaseous phase outlet 21 of First Heat Exchanger 12; The described liquidus temperature entering the low-boiling point material of the two-stage compression air inlet of unstripped gas four-stage compressor 1 is :-14 DEG C, and pressure is 1.0Mpa.

Embodiment two

Step one: unstripped gas enters the first reboiler 2 import by air inlet surge tank 22 and unstripped gas four-stage compressor 1, and the component of described unstripped gas is: carbon dioxide 99%, water 0.4%, alcohol 0.5%, hydrocarbon 0.1%, and temperature is: 40 DEG C, and pressure is: 0.2Mpa; Described unstripped gas by the temperature after unstripped gas four-stage compressor 1 is: 120 DEG C, and pressure is 6Mpa;

Step 2: make to enter the first reboiler 2 imported materials gas described in step one and enter in the first rectifying column 3 by the raw material gas inlet of the first reboiler 2 and the first rectifying column 3 middle and lower part; The raw material gas inlet of described first rectifying column 3 middle and lower part goes out unstripped gas temperature and is: 80 DEG C;

Step 3: make to enter described in step 2 unstripped gas in the first rectifying column 3 and overhead condenser 5 and carry out mass-and heat-transfer by the low-boiling point material entering the first rectifying column 3 in the fluid inlet on the first threeway 13 and the first rectifying column 3 top, high boiling substance after mass-and heat-transfer enters in collector 4 by the liquid-phase outlet bottom the first rectifying column 3 after condensation, and its low-boiling point material enters in overhead condenser 5 by the gaseous phase outlet at the first rectifying column 3 top and the gas phase import of overhead condenser 5; High boiling substance component in the described collector 4 entered is: carbon dioxide 35%, alcohol 9.9%, water 55%, hydro carbons 0.1%, and temperature is: 80 DEG C, and pressure is 6Mpa;

Step 4: make the liquid phase of the low-boiling point material in overhead condenser 5 described in step 3 by the first threeway 13, the liquid phase of part low-boiling point material enters in the first rectifying column 3 in the fluid inlet on the first rectifying column 3 top carries out mass-and heat-transfer with the unstripped gas in the first rectifying column 3, the liquid phase of another part low-boiling point material is divided into two-way, and first via inlet in the middle part of the second reboiler 8, the 3rd threeway 15, first control valve 10 and Second distillation column 9 enters the inside of Second distillation column 9; Second tunnel second reboiler the 8, the 3rd threeway 15 and the second control valve 11 enter the tube side of the second heat exchanger 6; The described liquidus temperature entering the low-boiling point material of Second distillation column 9 inside is: 5 DEG C, and pressure is 6Mpa, and flow is 748Nm ³/ h; The liquid phase component of low-boiling point material in described rectifying column overhead condenser 5: carbon dioxide 99.3%, foreign gas 0.7%, temperature is 5 DEG C, and pressure is 4.8Mpa; The liquidus temperature entering the low-boiling point material of the second heat exchanger 6 tube side is :-30 DEG C, and pressure is 2.0Mpa;

Step 5: the carbon dioxide rich solution that the liquid phase of the low-boiling point material entering Second distillation column 9 inside described in step 4 and the fluid inlet by the liquid-phase outlet bottom gas-liquid separator 7 and Second distillation column 9 top are entered in Second distillation column 9 carries out mass-and heat-transfer, after mass-and heat-transfer, the gas phase of secondary low-boiling point material discharges Second distillation column 9 by the gaseous phase outlet at Second distillation column 9 top, and its secondary high boiling substance enters in carbon dioxide storage tank 16 by the inlet of the liquid-phase outlet bottom Second distillation column 9, First Heat Exchanger 12 and the liquid outlet of First Heat Exchanger 12; Liquid-phase outlet secondary high boiling substance component bottom described Second distillation column 9 is: carbon dioxide 99.99%, flow is: 666Nm ³/ h, temperature is :-10 DEG C, and pressure is 3.0Mpa; The temperature of the secondary high boiling substance of the inlet of described First Heat Exchanger 12 is :-10 ~-20 DEG C, and pressure is: 3.0Mpa; The temperature of the liquid outlet secondary high boiling substance of described First Heat Exchanger 12 is :-15 DEG C, pressure is: 3.0Mpa; The described secondary high boiling substance entered in carbon dioxide storage tank 16 is food-grade carbon-dioxide, and its carbon dioxide content is 99.99%;

Step 6: make the gas phase of the low-boiling point material in overhead condenser 5 described in step 3 enter in the shell side of the second heat exchanger 6 by overhead condenser 5 gaseous phase outlet and the second threeway 14, the gas phase of the secondary low-boiling point material of discharging Second distillation column 9 described in step 5 is entered in the shell side of the second heat exchanger 6 by the second threeway 14, makes the gas phase of the gas phase of the gas phase of low-boiling point material and secondary low-boiling point material in the shell side of the second heat exchanger 6 after mixed heat transfer enter in gas-liquid separator 7; The gaseous component of the low-boiling point material of described overhead condenser 5 gaseous phase outlet is carbon dioxide 65%, and temperature is: 0 DEG C, and pressure is: 4.8Mpa; The gaseous component of the secondary low-boiling point material of described Second distillation column 9 is: carbon dioxide 91%, hydrogen 1%, oxygen 2.1%, nitrogen 5.9%, and temperature is: 0 DEG C, and pressure is 2.5Mpa; Gas temperature in described second heat exchanger 6 shell side after mixed heat transfer is :-30 DEG C, pressure is: 1.26Mpa;

Step 7: make the gas phase entered described in step 6 in gas-liquid separator 7 after mixed heat transfer carry out gas-liquid separation, carbon dioxide rich solution after gas-liquid separation enters in Second distillation column 9 by the fluid inlet on the liquid-phase outlet bottom gas-liquid separator 7 and Second distillation column 9 top, and the waste gas after gas-liquid separation enters waste gas header 17 by the first gaseous phase outlet 19 of the gaseous phase outlet at gas-liquid separator 7 top, the first gas phase import 18 of First Heat Exchanger 12 and First Heat Exchanger 12; Described go out the carbon dioxide rich solution component of liquid-phase outlet bottom gas-liquid separator 7 be: carbon dioxide 90%, temperature is :-10 DEG C, and pressure is 3.0MPa; Described go out the waste gas component of gaseous phase outlet at gas-liquid separator 7 top be: carbon dioxide 52%, temperature is-10 DEG C, and pressure is 3.0MPa;

Step 8: make the liquid phase of the low-boiling point material entering the second heat exchanger 6 tube side described in step 4 be entered the two-stage compression air inlet of unstripped gas four-stage compressor 1 successively by the second gas phase import 20 of the second heat exchanger 6 tube side, First Heat Exchanger 12 and the second gaseous phase outlet 21 of First Heat Exchanger 12; The described liquidus temperature entering the low-boiling point material of the two-stage compression air inlet of unstripped gas four-stage compressor 1 is :-14 DEG C, and pressure is 2.0Mpa.

Embodiment three

Step one: unstripped gas enters the first reboiler 2 import by air inlet surge tank 22 and unstripped gas four-stage compressor 1, and the component of described unstripped gas is: carbon dioxide 97%, water 0.4%, alcohol 2%, hydrocarbon 0.6%, and temperature is: 25 DEG C, and pressure is: 0.15Mpa; Described unstripped gas by the temperature after unstripped gas four-stage compressor 1 is: 105 DEG C, and pressure is 5Mpa;

Step 2: make to enter the first reboiler 2 imported materials gas described in step one and enter in the first rectifying column 3 by the raw material gas inlet of the first reboiler 2 and the first rectifying column 3 middle and lower part; The raw material gas inlet of described first rectifying column 3 middle and lower part goes out unstripped gas temperature and is: 55 DEG C;

Step 3: make to enter described in step 2 unstripped gas in the first rectifying column 3 and overhead condenser 5 and carry out mass-and heat-transfer by the low-boiling point material entering the first rectifying column 3 in the fluid inlet on the first threeway 13 and the first rectifying column 3 top, high boiling substance after mass-and heat-transfer enters in collector 4 by the liquid-phase outlet bottom the first rectifying column 3 after condensation, and its low-boiling point material enters in overhead condenser 5 by the gaseous phase outlet at the first rectifying column 3 top and the gas phase import of overhead condenser 5; High boiling substance component in the described collector 4 entered is: carbon dioxide 32.5%, alcohol 8%, water 59%, hydro carbons 0.5%, and temperature is: 65 DEG C, and pressure is 5Mpa;

Step 4: make the liquid phase of the low-boiling point material in overhead condenser 5 described in step 3 by the first threeway 13, the liquid phase of part low-boiling point material enters in the first rectifying column 3 in the fluid inlet on the first rectifying column 3 top carries out mass-and heat-transfer with the unstripped gas in the first rectifying column 3, the liquid phase of another part low-boiling point material is divided into two-way, and first via inlet in the middle part of the second reboiler 8, the 3rd threeway 15, first control valve 10 and Second distillation column 9 enters the inside of Second distillation column 9; Second tunnel second reboiler the 8, the 3rd threeway 15 and the second control valve 11 enter the tube side of the second heat exchanger 6; The described liquidus temperature entering the low-boiling point material of Second distillation column 9 inside is :-2.5 DEG C, and pressure is 5Mpa, and flow is 748Nm ³/ h; The liquid phase component of low-boiling point material in described rectifying column overhead condenser 5: carbon dioxide 99.3%, foreign gas 0.7%, temperature is-2.5 DEG C, and pressure is 4.8Mpa; The liquidus temperature entering the low-boiling point material of the second heat exchanger 6 tube side is :-37.5 DEG C, and pressure is 1.5Mpa;

Step 5: the carbon dioxide rich solution that the liquid phase of the low-boiling point material entering Second distillation column 9 inside described in step 4 and the fluid inlet by the liquid-phase outlet bottom gas-liquid separator 7 and Second distillation column 9 top are entered in Second distillation column 9 carries out mass-and heat-transfer, after mass-and heat-transfer, the gas phase of secondary low-boiling point material discharges Second distillation column 9 by the gaseous phase outlet at Second distillation column 9 top, and its secondary high boiling substance enters in carbon dioxide storage tank 16 by the inlet of the liquid-phase outlet bottom Second distillation column 9, First Heat Exchanger 12 and the liquid outlet of First Heat Exchanger 12; Liquid-phase outlet secondary high boiling substance component bottom described Second distillation column 9 is: carbon dioxide 99.99%, flow is: 666Nm ³/ h, temperature is :-15 DEG C, and pressure is 2.1Mpa; The temperature of the secondary high boiling substance of the inlet of described First Heat Exchanger 12 is :-10 ~-20 DEG C, and pressure is: 2.2Mpa; The temperature of the liquid outlet secondary high boiling substance of described First Heat Exchanger 12 is :-17.5 DEG C, pressure is: 2.1Mpa; The described secondary high boiling substance entered in carbon dioxide storage tank 16 is food-grade carbon-dioxide, and its carbon dioxide content is 99.99%;

Step 6: make the gas phase of the low-boiling point material in overhead condenser 5 described in step 3 enter in the shell side of the second heat exchanger 6 by overhead condenser 5 gaseous phase outlet and the second threeway 14, the gas phase of the secondary low-boiling point material of discharging Second distillation column 9 described in step 5 is entered in the shell side of the second heat exchanger 6 by the second threeway 14, makes the gas phase of the gas phase of the gas phase of low-boiling point material and secondary low-boiling point material in the shell side of the second heat exchanger 6 after mixed heat transfer enter in gas-liquid separator 7; The gaseous component of the low-boiling point material of described overhead condenser 5 gaseous phase outlet is carbon dioxide 57.5%, and temperature is :-5 DEG C, and pressure is: 4.8Mpa; The gaseous component of the secondary low-boiling point material of described Second distillation column 9 is: carbon dioxide 91%, hydrogen 1%, oxygen 2.1%, nitrogen 5.9%, and temperature is :-7.5 DEG C, and pressure is 1.7Mpa; Gas temperature in described second heat exchanger 6 shell side after mixed heat transfer is :-30 DEG C, pressure is: 1.26Mpa;

Step 7: make the gas phase entered described in step 6 in gas-liquid separator 7 after mixed heat transfer carry out gas-liquid separation, carbon dioxide rich solution after gas-liquid separation enters in Second distillation column 9 by the fluid inlet on the liquid-phase outlet bottom gas-liquid separator 7 and Second distillation column 9 top, and the waste gas after gas-liquid separation enters waste gas header 17 by the first gaseous phase outlet 19 of the gaseous phase outlet at gas-liquid separator 7 top, the first gas phase import 18 of First Heat Exchanger 12 and First Heat Exchanger 12; Described go out the carbon dioxide rich solution component of liquid-phase outlet bottom gas-liquid separator 7 be: carbon dioxide 85%, temperature is :-21 DEG C, and pressure is 2.3MPa; Described go out the waste gas component of gaseous phase outlet at gas-liquid separator 7 top be: carbon dioxide 41%, temperature is-21 DEG C, and pressure is 2.3MPa;

Step 8: make the liquid phase of the low-boiling point material entering the second heat exchanger 6 tube side described in step 4 be entered the two-stage compression air inlet of unstripped gas four-stage compressor 1 successively by the second gas phase import 20 of the second heat exchanger 6 tube side, First Heat Exchanger 12 and the second gaseous phase outlet 21 of First Heat Exchanger 12; The described liquidus temperature entering the low-boiling point material of the two-stage compression air inlet of unstripped gas four-stage compressor 1 is :-14 DEG C, and pressure is 1.5Mpa.

Embodiment four

Step one: unstripped gas enters the first reboiler 2 import by air inlet surge tank 22 and unstripped gas four-stage compressor 1, and the component of described unstripped gas is: carbon dioxide 98.1%, water 1%, and alcohol 0.4%, hydrocarbon 0.5%, flow is: 770Nm ³/ h, temperature is: 40 DEG C, and pressure is: 0.12Mpa; Described unstripped gas by the temperature after unstripped gas four-stage compressor 1 is: 100 DEG C, and pressure is 4.8Mpa;

Step 2: make to enter the first reboiler 2 imported materials gas described in step one and enter in the first rectifying column 3 by the raw material gas inlet of the first reboiler 2 and the first rectifying column 3 middle and lower part; The raw material gas inlet of described first rectifying column 3 middle and lower part goes out unstripped gas temperature and is: 65 DEG C;

Step 3: make to enter described in step 2 unstripped gas in the first rectifying column 3 and overhead condenser 5 and carry out mass-and heat-transfer by the low-boiling point material entering the first rectifying column 3 in the fluid inlet on the first threeway 13 and the first rectifying column 3 top, high boiling substance after mass-and heat-transfer enters in collector 4 by the liquid-phase outlet bottom the first rectifying column 3 after condensation, and its low-boiling point material enters in overhead condenser 5 by the gaseous phase outlet at the first rectifying column 3 top and the gas phase import of overhead condenser 5; High boiling substance component in the described collector 4 entered is: carbon dioxide 31.8%, alcohol 10.3%, water 57.8%, hydro carbons 0.1%, and temperature is: 69.4 DEG C, and pressure is 4.8Mpa;

Step 4: make the liquid phase of the low-boiling point material in overhead condenser 5 described in step 3 by the first threeway 13, the liquid phase of part low-boiling point material enters in the first rectifying column 3 in the fluid inlet on the first rectifying column 3 top carries out mass-and heat-transfer with the unstripped gas in the first rectifying column 3, the liquid phase of another part low-boiling point material is divided into two-way, and first via inlet in the middle part of the second reboiler 8, the 3rd threeway 15, first control valve 10 and Second distillation column 9 enters the inside of Second distillation column 9; Second tunnel second reboiler the 8, the 3rd threeway 15 and the second control valve 11 enter the tube side of the second heat exchanger 6; The described liquidus temperature entering the low-boiling point material of Second distillation column 9 inside is :-10 DEG C, and pressure is 4.8Mpa, and flow is 748Nm ³/ h; The liquid phase component of low-boiling point material in described rectifying column overhead condenser 5: carbon dioxide 99.3%, foreign gas 0.7%, temperature is-5 DEG C, and pressure is 4.8Mpa; The liquidus temperature entering the low-boiling point material of the second heat exchanger 6 tube side is :-34.5 DEG C, and pressure is 1.26Mpa;

Step 5: the carbon dioxide rich solution that the liquid phase of the low-boiling point material entering Second distillation column 9 inside described in step 4 and the fluid inlet by the liquid-phase outlet bottom gas-liquid separator 7 and Second distillation column 9 top are entered in Second distillation column 9 carries out mass-and heat-transfer, after mass-and heat-transfer, the gas phase of secondary low-boiling point material discharges Second distillation column 9 by the gaseous phase outlet at Second distillation column 9 top, and its secondary high boiling substance enters in carbon dioxide storage tank 16 by the inlet of the liquid-phase outlet bottom Second distillation column 9, First Heat Exchanger 12 and the liquid outlet of First Heat Exchanger 12; Liquid-phase outlet secondary high boiling substance component bottom described Second distillation column 9 is: carbon dioxide 99.99%, flow is: 666Nm ³/ h, temperature is :-12.1 DEG C, and pressure is 2.5Mpa; The temperature of the secondary high boiling substance of the inlet of described First Heat Exchanger 12 is :-10 ~-20 DEG C, and pressure is: 2.5Mpa; The temperature of the liquid outlet secondary high boiling substance of described First Heat Exchanger 12 is :-15 DEG C, pressure is: 2.5Mpa; The described secondary high boiling substance entered in carbon dioxide storage tank 16 is food-grade carbon-dioxide, and its carbon dioxide content is 99.99%;

Step 6: make the gas phase of the low-boiling point material in overhead condenser 5 described in step 3 enter in the shell side of the second heat exchanger 6 by overhead condenser 5 gaseous phase outlet and the second threeway 14, the gas phase of the secondary low-boiling point material of discharging Second distillation column 9 described in step 5 is entered in the shell side of the second heat exchanger 6 by the second threeway 14, makes the gas phase of the gas phase of the gas phase of low-boiling point material and secondary low-boiling point material in the shell side of the second heat exchanger 6 after mixed heat transfer enter in gas-liquid separator 7; The gaseous component of the low-boiling point material of described overhead condenser 5 gaseous phase outlet is carbon dioxide 63.1%, and temperature is :-5 DEG C, and pressure is: 4.8Mpa; The gaseous component of the secondary low-boiling point material of described Second distillation column 9 is: carbon dioxide 91%, hydrogen 1%, oxygen 2.1%, nitrogen 5.9%, and temperature is :-15.2 DEG C, and pressure is 2.5Mpa; Gas temperature in described second heat exchanger 6 shell side after mixed heat transfer is :-30 DEG C, pressure is: 1.26Mpa;

Step 7: make the gas phase entered described in step 6 in gas-liquid separator 7 after mixed heat transfer carry out gas-liquid separation, carbon dioxide rich solution after gas-liquid separation enters in Second distillation column 9 by the fluid inlet on the liquid-phase outlet bottom gas-liquid separator 7 and Second distillation column 9 top, and the waste gas after gas-liquid separation enters waste gas header 17 by the first gaseous phase outlet 19 of the gaseous phase outlet at gas-liquid separator 7 top, the first gas phase import 18 of First Heat Exchanger 12 and First Heat Exchanger 12; Described go out the carbon dioxide rich solution component of liquid-phase outlet bottom gas-liquid separator 7 be: carbon dioxide 88.2%, temperature is :-32 DEG C, and pressure is 2.5MPa; Described go out the waste gas component of gaseous phase outlet at gas-liquid separator 7 top be: carbon dioxide 43.8%, temperature is-32 DEG C, and pressure is 2.5MPa;

Step 8: make the liquid phase of the low-boiling point material entering the second heat exchanger 6 tube side described in step 4 be entered the two-stage compression air inlet of unstripped gas four-stage compressor 1 successively by the second gas phase import 20 of the second heat exchanger 6 tube side, First Heat Exchanger 12 and the second gaseous phase outlet 21 of First Heat Exchanger 12; The described liquidus temperature entering the low-boiling point material of the two-stage compression air inlet of unstripped gas four-stage compressor 1 is :-14 DEG C, and pressure is 1.26Mpa.

Above-described embodiment is only for clearly example being described, and the restriction not to embodiment.For the common technique personnel in affiliated field, can also make other changes in different forms on the basis of the above description.Here exhaustive without the need to also giving all embodiments, and thus the apparent change of amplifying out or variation be still among the protection domain of the invention claim.

Claims

1. the device utilizing two-tower rectification purification to produce food-class liquid CO 2, it is characterized in that: this device comprises air inlet surge tank (22), air inlet surge tank (22) outlet is connected by the import of pipeline with unstripped gas four-stage compressor (1), the outlet of unstripped gas four-stage compressor (1) is connected by the raw material gas inlet of the first reboiler (2) with the first rectifying column (3) middle and lower part, the liquid-phase outlet of the first rectifying column (3) bottom is connected with collector (4), the gaseous phase outlet at the first rectifying column (3) top is connected with the gas phase import of overhead condenser (5), the liquid-phase outlet of overhead condenser (5) is connected by the fluid inlet of pipeline with the first rectifying column (3) top, pipeline between the liquid-phase outlet of overhead condenser (5) and the fluid inlet on the first rectifying column (3) top is provided with the first threeway (13), 3rd end of the first threeway (13) by pipeline successively with the second reboiler (8), first control valve (10) is connected with Second distillation column (9) middle part inlet, the liquid-phase outlet of Second distillation column (9) bottom is connected by the inlet of pipeline with First Heat Exchanger (12), and the liquid outlet of First Heat Exchanger (12) is connected with carbon dioxide storage tank (16), the gaseous phase outlet at described overhead condenser (5) top is connected with gas-liquid separator (7) with the shell side of the second heat exchanger (6) by the second threeway (14), the liquid-phase outlet of gas-liquid separator (7) bottom is connected by the fluid inlet of pipeline with Second distillation column (9) top, the gaseous phase outlet at gas-liquid separator (7) top is connected with the first gas phase import (18) of First Heat Exchanger (12), and first gaseous phase outlet (19) of First Heat Exchanger (12) is connected with waste gas header (17), the gaseous phase outlet at described Second distillation column (9) top is connected with the 3rd end of the second threeway (14) by pipeline, pipeline between described second reboiler (8) and the first control valve (10) is provided with the 3rd threeway (15), 3rd end of described 3rd threeway (15) is connected with the second gas phase import (20) of First Heat Exchanger (12) with the tube side of the second heat exchanger (6) by the second control valve (11), and second gaseous phase outlet (21) of First Heat Exchanger (12) is connected by the two-stage compression air inlet of pipeline with unstripped gas four-stage compressor (1).

2. a kind of method utilizing two-tower rectification purification to produce food-class liquid CO 2 device according to claim 1, is characterized in that: this process comprises the steps:

Step one: unstripped gas enters the first reboiler (2) import by air inlet surge tank (22) and unstripped gas four-stage compressor (1), the component of described unstripped gas is: carbon dioxide 95 ~ 99%, water 0.4 ~ 2%, alcohol 0.1 ~ 2%, hydrocarbon 0.1 ~ 1%, temperature is: 10 ~ 40 DEG C, and pressure is: 0.1 ~ 0.2Mpa; Described unstripped gas by the temperature after unstripped gas four-stage compressor (1) is: 90 ~ 120 DEG C, and pressure is 4 ~ 6Mpa;

Step 2: make to enter the first reboiler (2) imported materials gas described in step one and enter in the first rectifying column (3) by the raw material gas inlet of the first reboiler (2) and the first rectifying column (3) middle and lower part; The raw material gas inlet of described first rectifying column (3) middle and lower part goes out unstripped gas temperature and is: 30 ~ 80 DEG C;

Step 3: make to enter described in step 2 unstripped gas in the first rectifying column (3) and overhead condenser (5) and carry out mass-and heat-transfer by the low-boiling point material entering the first rectifying column (3) in the fluid inlet on the first threeway (13) and the first rectifying column (3) top, high boiling substance after mass-and heat-transfer enters in collector (4) by the liquid-phase outlet of the first rectifying column (3) bottom after condensation, its low-boiling point material enters in overhead condenser (5) by the gaseous phase outlet at the first rectifying column (3) top and the gas phase import of overhead condenser (5), high boiling substance component in the described collector (4) entered is: carbon dioxide 30 ~ 35%, alcohol 5 ~ 11%, water 40 ~ 60%, hydro carbons 0.1 ~ 1%, and temperature is: 50 ~ 80 DEG C, and pressure is 4 ~ 6Mpa,

Step 4: make the liquid phase of the low-boiling point material in overhead condenser described in step 3 (5) by the first threeway (13), the liquid phase of part low-boiling point material enters in the first rectifying column (3) in the fluid inlet on the first rectifying column (3) top carries out mass-and heat-transfer with the unstripped gas in the first rectifying column (3), the liquid phase of another part low-boiling point material is divided into two-way, the first via is through the second reboiler (8), 3rd threeway (15), first control valve (10) and Second distillation column (9) middle part inlet enter the inside of Second distillation column (9), second tunnel second reboiler (8), the 3rd threeway (15) and the second control valve (11) enter the tube side of the second heat exchanger (6), the described liquidus temperature entering the inner low-boiling point material of Second distillation column (9) is: 5 ~-10 DEG C, pressure is 4 ~ 6Mpa, and flow is 748Nm ³/ h, the liquid phase component of low-boiling point material in described rectifying column overhead condenser (5): carbon dioxide 99.3%, foreign gas 0.7%, temperature is 5 ~-10 DEG C, and pressure is 4.8Mpa, the liquidus temperature entering the low-boiling point material of the second heat exchanger (6) tube side is :-30 ~-45 DEG C, and pressure is 1.0 ~ 2.0Mpa,

Step 5: make the liquid phase entering the inner low-boiling point material of Second distillation column (9) described in step 4 carry out mass-and heat-transfer with the carbon dioxide rich solution entered in Second distillation column (9) by the liquid-phase outlet of gas-liquid separator (7) bottom and the fluid inlet on Second distillation column (9) top, after mass-and heat-transfer, the gas phase of secondary low-boiling point material discharges Second distillation column (9) by the gaseous phase outlet at Second distillation column (9) top, its secondary high boiling substance is by the liquid-phase outlet of Second distillation column (9) bottom, the inlet of First Heat Exchanger (12) and the liquid outlet of First Heat Exchanger (12) enter in carbon dioxide storage tank (16), the liquid-phase outlet secondary high boiling substance component of described Second distillation column (9) bottom is: carbon dioxide 99.99%, flow is: 666Nm ³/ h, temperature is :-10 ~-20 DEG C, and pressure is 1.5 ~ 3.0Mpa, the temperature of the secondary high boiling substance of the inlet of described First Heat Exchanger (12) is :-10 ~-20 DEG C, and pressure is: 1.5 ~ 3.0Mpa, the temperature of the liquid outlet secondary high boiling substance of described First Heat Exchanger (12) is :-15 DEG C ~-20 DEG C, pressure is: 1.5 ~ 3.0Mpa, the described secondary high boiling substance entered in carbon dioxide storage tank (16) is food-grade carbon-dioxide, and its carbon dioxide content is 99.99%,

Step 6: make the gas phase of the low-boiling point material in overhead condenser described in step 3 (5) enter in the shell side of the second heat exchanger (6) by overhead condenser (5) gaseous phase outlet and the second threeway (14), the gas phase of the secondary low-boiling point material of discharging Second distillation column (9) described in step 5 is made to enter in the shell side of the second heat exchanger (6) by the second threeway (14), the gas phase of the gas phase of the gas phase of low-boiling point material and secondary low-boiling point material in the shell side of the second heat exchanger (6) after mixed heat transfer is made to enter in gas-liquid separator (7), the gaseous component of the low-boiling point material of described overhead condenser (5) gaseous phase outlet is carbon dioxide 50 ~ 65%, and temperature is: 0 ~-10 DEG C, pressure is: 4.8Mpa, the gaseous component of the secondary low-boiling point material of described Second distillation column (9) is: carbon dioxide 91%, hydrogen 1%, oxygen 2.1%, nitrogen 5.9%, and temperature is: 0 ~-15 DEG C, and pressure is 1.0 ~ 2.5Mpa, gas temperature in described second heat exchanger (6) shell side after mixed heat transfer is :-30 DEG C, pressure is: 1.26Mpa,

Step 7: make the gas phase after entering gas-liquid separator (7) interior mixed heat transfer described in step 6 carry out gas-liquid separation, carbon dioxide rich solution after gas-liquid separation enters in Second distillation column (9) by the liquid-phase outlet of gas-liquid separator (7) bottom and the fluid inlet on Second distillation column (9) top, and the waste gas after gas-liquid separation enters waste gas header (17) by first gaseous phase outlet (19) of the gaseous phase outlet at gas-liquid separator (7) top, the first gas phase import (18) of First Heat Exchanger (12) and First Heat Exchanger (12); Described go out the carbon dioxide rich solution component of liquid-phase outlet of gas-liquid separator (7) bottom be: carbon dioxide 80 ~ 90%, temperature is :-10 ~-32 DEG C, and pressure is 1.5 ~ 3.0MPa; Described go out the waste gas component of gaseous phase outlet at gas-liquid separator (7) top be: carbon dioxide 30 ~ 52%, temperature is-10 ~-32 DEG C, and pressure is 1.5 ~ 3.0MPa;

Step 8: make the liquid phase of the low-boiling point material entering the second heat exchanger (6) tube side described in step 4 be entered the two-stage compression air inlet of unstripped gas four-stage compressor (1) successively by the second heat exchanger (6) tube side, the second gas phase import (20) of First Heat Exchanger (12) and second gaseous phase outlet (21) of First Heat Exchanger (12); The described liquidus temperature entering the low-boiling point material of the two-stage compression air inlet of unstripped gas four-stage compressor (1) is :-14 DEG C, and pressure is 1.0 ~ 2.0Mpa.

3. the method utilizing two-tower rectification purification to produce food-class liquid CO 2 device according to claim 2, is characterized in that: this process comprises the steps:

Step one: unstripped gas enters the first reboiler (2) import by air inlet surge tank (22) and unstripped gas four-stage compressor (1), the component of described unstripped gas is: carbon dioxide 98.1%, water 1%, alcohol 0.4%, hydrocarbon 0.5%, flow is: 770Nm ³/ h, temperature is: 40 DEG C, and pressure is: 0.12Mpa; Described unstripped gas by the temperature after unstripped gas four-stage compressor (1) is: 100 DEG C, and pressure is 4.8Mpa;

Step 2: make to enter the first reboiler (2) imported materials gas described in step one and enter in the first rectifying column (3) by the raw material gas inlet of the first reboiler (2) and the first rectifying column (3) middle and lower part; The raw material gas inlet of described first rectifying column (3) middle and lower part goes out unstripped gas temperature and is: 65 DEG C;

Step 3: make to enter described in step 2 unstripped gas in the first rectifying column (3) and overhead condenser (5) and carry out mass-and heat-transfer by the low-boiling point material entering the first rectifying column (3) in the fluid inlet on the first threeway (13) and the first rectifying column (3) top, high boiling substance after mass-and heat-transfer enters in collector (4) by the liquid-phase outlet of the first rectifying column (3) bottom after condensation, its low-boiling point material enters in overhead condenser (5) by the gaseous phase outlet at the first rectifying column (3) top and the gas phase import of overhead condenser (5), high boiling substance component in the described collector (4) entered is: carbon dioxide 31.8%, alcohol 10.3%, water 57.8%, hydro carbons 0.1%, and temperature is: 69.4 DEG C, and pressure is 4.8Mpa,

Step 4: make the liquid phase of the low-boiling point material in overhead condenser described in step 3 (5) by the first threeway (13), the liquid phase of part low-boiling point material enters in the first rectifying column (3) in the fluid inlet on the first rectifying column (3) top carries out mass-and heat-transfer with the unstripped gas in the first rectifying column (3), the liquid phase of another part low-boiling point material is divided into two-way, the first via is through the second reboiler (8), 3rd threeway (15), first control valve (10) and Second distillation column (9) middle part inlet enter the inside of Second distillation column (9), second tunnel second reboiler (8), the 3rd threeway (15) and the second control valve (11) enter the tube side of the second heat exchanger (6), the described liquidus temperature entering the inner low-boiling point material of Second distillation column (9) is :-10 DEG C, pressure is 4.8Mpa, and flow is 748Nm ³/ h, the liquid phase component of low-boiling point material in described rectifying column overhead condenser (5): carbon dioxide 99.3%, foreign gas 0.7%, temperature is-5 DEG C, and pressure is 4.8Mpa, the liquidus temperature entering the low-boiling point material of the second heat exchanger (6) tube side is :-34.5 DEG C, and pressure is 1.26Mpa,

Step 5: make the liquid phase entering the inner low-boiling point material of Second distillation column (9) described in step 4 carry out mass-and heat-transfer with the carbon dioxide rich solution entered in Second distillation column (9) by the liquid-phase outlet of gas-liquid separator (7) bottom and the fluid inlet on Second distillation column (9) top, after mass-and heat-transfer, the gas phase of secondary low-boiling point material discharges Second distillation column (9) by the gaseous phase outlet at Second distillation column (9) top, its secondary high boiling substance is by the liquid-phase outlet of Second distillation column (9) bottom, the inlet of First Heat Exchanger (12) and the liquid outlet of First Heat Exchanger (12) enter in carbon dioxide storage tank (16), the liquid-phase outlet secondary high boiling substance component of described Second distillation column (9) bottom is: carbon dioxide 99.99%, flow is: 666Nm ³/ h, temperature is :-12.1 DEG C, and pressure is 2.5Mpa, the temperature of the secondary high boiling substance of the inlet of described First Heat Exchanger (12) is :-10 ~-20 DEG C, and pressure is: 2.5Mpa, the temperature of the liquid outlet secondary high boiling substance of described First Heat Exchanger (12) is :-15 DEG C, pressure is: 2.5Mpa, the described secondary high boiling substance entered in carbon dioxide storage tank (16) is food-grade carbon-dioxide, and its carbon dioxide content is 99.99%,

Step 6: make the gas phase of the low-boiling point material in overhead condenser described in step 3 (5) enter in the shell side of the second heat exchanger (6) by overhead condenser (5) gaseous phase outlet and the second threeway (14), the gas phase of the secondary low-boiling point material of discharging Second distillation column (9) described in step 5 is made to enter in the shell side of the second heat exchanger (6) by the second threeway (14), the gas phase of the gas phase of the gas phase of low-boiling point material and secondary low-boiling point material in the shell side of the second heat exchanger (6) after mixed heat transfer is made to enter in gas-liquid separator (7), the gaseous component of the low-boiling point material of described overhead condenser (5) gaseous phase outlet is carbon dioxide 63.1%, and temperature is :-5 DEG C, and pressure is: 4.8Mpa, the gaseous component of the secondary low-boiling point material of described Second distillation column (9) is: carbon dioxide 91%, hydrogen 1%, oxygen 2.1%, nitrogen 5.9%, and temperature is :-15.2 DEG C, and pressure is 2.5Mpa, gas temperature in described second heat exchanger (6) shell side after mixed heat transfer is :-30 DEG C, pressure is: 1.26Mpa,

Step 7: make the gas phase after entering gas-liquid separator (7) interior mixed heat transfer described in step 6 carry out gas-liquid separation, carbon dioxide rich solution after gas-liquid separation enters in Second distillation column (9) by the liquid-phase outlet of gas-liquid separator (7) bottom and the fluid inlet on Second distillation column (9) top, and the waste gas after gas-liquid separation enters waste gas header (17) by first gaseous phase outlet (19) of the gaseous phase outlet at gas-liquid separator (7) top, the first gas phase import (18) of First Heat Exchanger (12) and First Heat Exchanger (12); Described go out the carbon dioxide rich solution component of liquid-phase outlet of gas-liquid separator (7) bottom be: carbon dioxide 88.2%, temperature is :-32 DEG C, and pressure is 2.5MPa; Described go out the waste gas component of gaseous phase outlet at gas-liquid separator (7) top be: carbon dioxide 43.8%, temperature is-32 DEG C, and pressure is 2.5MPa;

Step 8: make the liquid phase of the low-boiling point material entering the second heat exchanger (6) tube side described in step 4 be entered the two-stage compression air inlet of unstripped gas four-stage compressor (1) successively by the second heat exchanger (6) tube side, the second gas phase import (20) of First Heat Exchanger (12) and second gaseous phase outlet (21) of First Heat Exchanger (12); The described liquidus temperature entering the low-boiling point material of the two-stage compression air inlet of unstripped gas four-stage compressor (1) is :-14 DEG C, and pressure is 1.26Mpa.