Purification device system of food-grade liquid carbon dioxideTechnical Field
The utility model belongs to the technical field of carbon dioxide purification, and particularly relates to a purification device system of food-grade liquid carbon dioxide.
Background
Carbon dioxide is a precious resource and can be widely applied to various fields, and a large amount of carbon dioxide is needed in the industries of chemical synthesis industry, mechanical protection welding, metal casting processing, agricultural fertilization, fruit and vegetable fresh-keeping, beer and beverage filling, petroleum exploitation, fire fighting, medicine and health and the like. The carbon dioxide sources in China are very rich, but the measures for recycling the carbon dioxide are unfavorable, the carbon dioxide recycled each year is less than 1% of emission, the pollution to the atmosphere is caused, the terrible greenhouse effect is formed, and precious resources are wasted.
In the existing carbon dioxide purification technology, a shell-and-tube type heat exchanger is mostly adopted, and raw material gas exchanges heat with a low-temperature low-pressure refrigerant obtained by throttling a high-pressure refrigerant provided by a refrigerating unit until the raw material gas is liquefied and is purified by a purification tower to obtain food-grade carbon dioxide. The device is generally of a frame structure, equipment is scattered, the occupied area is large, and the running cooling capacity is large. The shell-and-tube heat exchanger has large volume, large cold energy loss and high manufacturing cost. The shell-and-tube heat exchanger exchanges heat for two flows (cold flow and hot flow), the temperature difference of the hot end is large, and the heat exchange effect is poor. The refrigerating unit has high energy consumption.
CN 106185935A discloses a liquefaction and purification process of a carbon dioxide liquefaction and purification device, the liquefaction and purification process comprises the steps that raw gas after purification treatment and precooling passes through a primary liquefier, a secondary liquefier and a tertiary liquefier, is cooled step by step, enters a rectifying tower in a gas-liquid two-phase state, enters the secondary liquefier after light components are removed in the rectifying tower, is heated in the secondary liquefier to evaporate impurities, enters a subcooler to be cooled into a liquid product, and is sent to a finished product tank to be stored, bottled or loaded and delivered from a factory. According to the scheme, the carbon dioxide liquefying and purifying cold box device with low energy consumption and small occupied area can be obtained, but the obtained carbon dioxide cannot reach the edible grade.
In view of the foregoing, it is desirable to provide a system of devices that is energy efficient and that is capable of purifying food grade liquid carbon dioxide.
Disclosure of utility model
Aiming at the defects of the prior art, the utility model aims to provide a purification device system of food-grade liquid carbon dioxide. The utility model realizes the low-energy purification treatment of the food-grade liquid carbon dioxide through the equipment such as the coupling refrigeration equipment, the rectifying tower, the purified gas heat exchanger and the like.
To achieve the purpose, the utility model adopts the following technical scheme:
The utility model provides a purification device system of food-grade liquid carbon dioxide, which comprises a CO2 impurity removal device and a CO2 purified gas liquefaction purification device which are connected;
The CO2 purified gas liquefaction and purification device comprises refrigeration equipment and liquefaction and purification equipment, wherein the refrigeration equipment provides a cold source for the liquefaction and purification equipment;
According to the circulation direction of CO2 purified gas, the liquefaction purification equipment comprises a precooler, a liquefier, a rectifying tower, a subcooler and a storage tank which are sequentially connected.
According to the utility model, a CO2 impurity removing device is adopted to remove sulfur, hydrocarbon, combustible substances, water and other impurities in CO2 raw material gas, so that qualified CO2 purified gas with higher purity is obtained, and then light components in the CO2 purified gas are effectively removed through a purified gas liquefying and purifying device, and the output of liquid food grade carbon dioxide is realized by coupling refrigerating equipment.
According to the utility model, the light components in the CO2 purified gas are discharged from the top of the rectifying tower by heating the rectifying tower kettle and utilizing the boiling point difference of the gas, the qualified carbon dioxide is obtained from the rectifying tower kettle, and then the liquid storage of the food-grade carbon dioxide is realized through supercooling of refrigeration equipment.
As a preferred embodiment of the present utility model, the rectifying column includes an overhead condenser and a bottom reboiler.
Preferably, the outlet of the liquefier is connected to the inter-column inlet of the rectifying column.
Preferably, the CO2 outlet or the bottom inlet of the bottom reboiler is connected to the CO2 inlet of the subcooler.
As a preferable technical scheme of the utility model, the gas-phase cold source outlet of the refrigeration equipment is sequentially connected with a tower bottom reboiler, a liquefier and a refrigerant gas-liquid separation tank.
Preferably, the gas phase outlet of the refrigerant gas-liquid separation tank is connected with the refrigeration equipment.
As a preferable technical scheme of the utility model, the liquid-phase cold source outlet of the refrigeration equipment is divided into three branches, one branch is connected with the tower top condenser, the other branch is connected with the subcooler, and the other branch is connected with the liquefier.
Preferably, the product outlet of the overhead condenser is connected to the precooler.
Preferably, the cold source outlet of the tower top condenser is connected with the refrigerant gas-liquid separation tank.
Preferably, the outlet of the subcooler is connected to the refrigerant gas-liquid separation tank.
Preferably, the outlet of the liquefier is connected to the refrigerant gas-liquid separation tank.
As a preferable embodiment of the present utility model, the liquid phase outlet of the refrigerant gas-liquid separation tank is connected to the liquefier.
Preferably, the refrigeration device comprises a freon refrigerator.
In the utility model, the Freon refrigerator provides a cold source for liquefaction and purification equipment, more specifically, the gas-phase cold source provided by the Freon refrigerator is used for gasifying CO2 in a tower bottom reboiler, and the liquid-phase cold source provided by the Freon refrigerator can not only liquefy CO2 purified gas, but also provide a cold source for a tower top condenser of a rectifying tower, and can also supercool carbon dioxide obtained through rectification and purification. Therefore, the Freon refrigerator can effectively promote the rectification and purification of CO2 purified gas. In addition, after heat exchange, the cold source provided by the Freon refrigerator can flow back to the refrigerant gas-liquid separation tank for separation, and then flow back to the Freon refrigerator, so that the recycling of Freon is realized, and the waste of resources and the influence of gas-phase Freon on the environment are avoided.
As a preferable technical scheme of the utility model, the CO2 impurity removing device comprises a primary hydrolysis desulfurization reactor, a zinc oxide desulfurization reactor, a secondary hydrolysis desulfurization reactor, a purified gas heat exchanger, a heater and a hydrocarbon removal reactor which are sequentially connected.
Preferably, the outlet of the dealkylation reactor is connected with the purified gas heat exchanger.
Preferably, the CO2 purified gas outlet of the purified gas heat exchanger is connected with the drying equipment after being cooled.
The purification gas heat exchanger can greatly save energy consumption for a device system, and is particularly characterized in that (1) desulfurization reactions carried out in a primary hydrolysis desulfurization reactor, a zinc oxide desulfurization reactor and a secondary hydrolysis desulfurization reactor are high-temperature reactions to provide heat for the subsequent hydrocarbon removal process, and (2) the hydrocarbon removal reaction carried out in the hydrocarbon removal reactor is also high-temperature reactions, so that the obtained purification carbon dioxide has a large amount of heat, the purification gas heat exchanger can realize heat release for the purification carbon dioxide, reduce the temperature of the purification carbon dioxide, is more beneficial to the subsequent drying treatment, and provides heat for the hydrocarbon removal process.
The purification method of the food-grade liquid carbon dioxide by utilizing the purification device system of the food-grade liquid carbon dioxide comprises the steps of adopting a CO2 impurity removal device to remove impurities from CO2 raw material gas to obtain CO2 purified gas, and then adopting a CO2 purified gas liquefaction purification device to carry out liquefaction and purification to obtain the food-grade liquid carbon dioxide.
As a preferred embodiment of the present utility model, the purification method comprises the steps of:
(1) Sequentially carrying out desulfurization reaction, dealkylation reaction and drying treatment on the CO2 raw material gas to obtain CO2 purified gas;
The desulfurization reaction comprises primary hydrolysis desulfurization, zinc oxide desulfurization and secondary hydrolysis desulfurization which are sequentially carried out;
(2) And (3) sequentially liquefying, rectifying and purifying the CO2 purified gas obtained in the step (1) and supercooling to obtain the food-grade liquid carbon dioxide.
In a preferred embodiment of the present utility model, the temperature of the desulfurization reaction in the step (1) is 100 to 140 ℃, for example, 100 ℃, 110 ℃, 120 ℃, 130 ℃ or 140 ℃, but the present utility model is not limited to the recited values, and other values not recited in the numerical range are equally applicable.
Preferably, the pressure of the desulfurization reaction in the step (1) is 2.3 to 3.0mpa g, for example, 2.3mpa g, 2.4mpa g, 2.5mpa g, 2.6mpa g, 2.7mpa g, 2.8mpa g, 2.9mpa g or 3.0mpa g, but not limited to the values listed, and other values not listed in the numerical range are equally applicable.
The method comprises the steps of hydrolyzing and desulfurizing COS and other sulfides in CO2 raw material gas to generate easy-to-remove hydrogen sulfide COS+H283, wherein H2 S in carbon dioxide gas can be converted into zinc sulfide in the zinc oxide desulfurization process and then deposited in micropores of a desulfurizing agent, so that the H2 S content in the gas after passing through the wide-temperature zinc oxide fine desulfurizing agent is ensured to be less than 0.1 ppm. The chemical equation of the reaction is 2CO+O2＝2CO2、2H2+O2＝2H2 O and 2CH3OH+3O2＝2CO2+4H2 O.
Preferably, the catalyst used in the dealkylation in step (1) comprises a pt—pd based noble metal catalyst.
Preferably, the temperature of the dealkylation reaction in the step (1) is 300-470 ℃, for example, 300 ℃, 320 ℃, 340 ℃, 360 ℃, 380 ℃, 400 ℃, 420 ℃, 440 ℃ or 470 ℃, but the dealkylation reaction is not limited to the recited values, and other non-recited values in the numerical range are applicable.
Preferably, the pressure of the dealkylation reaction in the step (1) is 2.3-3.0 mpa g, for example, 2.3mpa g, 2.4mpa g, 2.5mpa g, 2.6mpa g, 2.7mpa g, 2.8mpa g, 2.9mpa g or 3.0mpa g, but not limited to the values listed, and other values not listed in the numerical range are equally applicable.
Preferably, the drying treatment of step (1) is performed using a 4A molecular sieve.
In the utility model, the 4A molecular sieve is an aluminosilicate microporous crystal, and a framework structure formed by SiO2 and Al2O3 tetrahedra can adsorb small-particle-diameter impurities in carbon dioxide gas, and particularly has higher selective adsorption capability on water than other molecules, so as to realize the drying treatment of the carbon dioxide gas.
Preferably, the temperature of the drying treatment in the step (1) is 10 to 40 ℃, for example, 10 ℃, 15 ℃, 20 ℃, 25 ℃, 30 ℃, 35 ℃ or 40 ℃, but the drying treatment is not limited to the recited values, and other non-recited values in the numerical range are equally applicable.
Preferably, the pressure of the drying treatment in the step (1) is 2.3 to 3.0mpa g, for example, 2.3mpa g, 2.4mpa g, 2.5mpa g, 2.6mpa g, 2.7mpa g, 2.8mpa g, 2.9mpa g or 3.0mpa g, but not limited to the values listed, and other values not listed in the numerical range are equally applicable.
Preferably, the S content of the CO2 purified gas is less than or equal to 0.1ppm, for example, 0.08ppm, 0.06ppm, 0.04ppm or 0.02ppm, but is not limited to the recited values, and other non-recited values in the numerical range are equally applicable;
Preferably, the water content of the CO2 purified gas is less than or equal to 12ppm, for example, 11ppm, 10ppm, 9ppm, 8ppm, 7ppm or 6ppm, but the water content is not limited to the recited values, and other values not recited in the numerical range are equally applicable;
Preferably, the hydrocarbon content of the CO2 purge gas is less than or equal to 30ppm, and may be, for example, 28ppm, 26ppm, 24ppm, 22ppm, 20ppm, or 18ppm, but is not limited to the recited values, and other values not recited in the numerical range are equally applicable.
As a preferred embodiment of the present utility model, the liquefaction treatment in step (2) includes pre-cooling and liquefaction performed sequentially.
Preferably, the end temperature of the pre-cooling is 4-8 ℃, for example, may be 4 ℃,5 ℃,6 ℃,7 ℃ or 8 ℃, but is not limited to the listed values, and other values not listed in the range of values are equally applicable.
Preferably, the end point temperature of the liquefaction process is-10 to-20 ℃, for example, -10 ℃, -12 ℃, -14 ℃, -16 ℃, -18 ℃, or-20 ℃, but not limited to the recited values, and other values not recited in the range of values are equally applicable.
Preferably, the temperature of the rectification and purification in the step (2) is-10 to-20 ℃, such as-10 ℃,12 ℃,14 ℃, 16 ℃, 18 ℃ or-20 ℃, but not limited to the recited values, and other values not recited in the numerical range are equally applicable.
Preferably, the pressure of the rectification and purification in the step (2) is 2.2-2.5 mpa g, for example, 2.2mpa g, 2.25mpa g, 2.3mpa g, 2.35mpa g, 2.4mpa g, 2.45mpa g or 2.5mpa g, but not limited to the values listed, and other values not listed in the numerical range are equally applicable.
Preferably, the supercooling temperature of the supercooling treatment in the step (2) is-30 to-23 ℃, for example, it may be-30 ℃, -29 ℃, -28 ℃, -27 ℃, -26 ℃, -25 ℃, -24 ℃, or-23 ℃, but not limited to the recited values, and other values not recited in the range of values are equally applicable.
Preferably, the pressure of the supercooling treatment in the step (2) is 2 to 2.5MPa, for example, 2MPa, 2.1MPa, 2.2MPa, 2.3MPa, 2.4MPa or 2.5MPa, but the pressure is not limited to the values listed, and other values not listed in the numerical range are equally applicable.
The numerical ranges recited herein include not only the above-listed point values, but also any point values between the above-listed numerical ranges that are not listed, and are limited in space and for the sake of brevity, the present utility model is not intended to be exhaustive of the specific point values that the stated ranges include.
The system refers to an equipment system, a device system or a production device.
Compared with the prior art, the utility model has the beneficial effects that:
(1) Compared with methanol cooling, the utility model realizes the recycling of heat in the device system by arranging the purified gas heat exchanger, thereby greatly saving energy consumption and avoiding the problem of insufficient supply of coolant;
(2) According to the utility model, heat exchange in the CO2 purified gas liquefaction and purification process is realized through the refrigeration equipment, so that the refrigeration and liquefaction of carbon dioxide are effectively realized, and the liquid storage of food-grade carbon dioxide is realized;
(3) The utility model can effectively remove light components in CO2 purified gas by coupling the rectifying tower and the refrigerating equipment, and reach the standard of qualified food-grade carbon dioxide.
Drawings
FIG. 1 is a schematic structural diagram of a CO2 purified gas liquefaction purification device provided in an embodiment of the present utility model;
FIG. 2 is a schematic structural diagram of a CO2 impurity removal device provided in an embodiment of the present utility model;
Wherein, 1 is freon refrigerator, 2 is precooler, 3 is liquefier, 4 is rectifying column, 5 is tower top condenser, 6 is tower bottom reboiler, 7 is subcooler, 8 is refrigerant gas-liquid separation jar, 9 is the storage tank, 10 is first-stage hydrolysis desulfurization reactor, 11 is zinc oxide desulfurization reactor, 12 is second-stage hydrolysis desulfurization reactor, 13 is purge gas heat exchanger, 14 is heater, 15 is hydrocarbon removal reactor, 16 is drying equipment.
Detailed Description
It is to be understood that in the description of the present utility model, the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the drawings, are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus are not to be construed as limiting the present utility model.
It should be noted that, in the description of the present utility model, unless explicitly specified and limited otherwise, the terms "disposed," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, integrally connected, mechanically connected, electrically connected, directly connected, indirectly connected through an intermediate medium, or communicating between the two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art in a specific case.
The technical scheme of the utility model is further described below by the specific embodiments with reference to the accompanying drawings.
The utility model provides a purification device system of food-grade liquid carbon dioxide, which comprises a CO2 impurity removal device shown in figure 2 and a CO2 purified gas liquefaction purification device shown in figure 1 which are connected;
The CO2 purified gas liquefaction and purification device comprises a Freon refrigerator 1 and liquefaction and purification equipment, wherein the Freon refrigerator 1 provides a cold source for the liquefaction and purification equipment;
According to the flowing direction of the CO2 purified gas, the liquefying and purifying device comprises a precooler 2, a liquefier 3, a rectifying tower 4, a subcooler 7 and a storage tank 9 which are sequentially connected.
The rectifying tower 4 comprises a tower top condenser 5 and a tower bottom reboiler 6, an outlet of the liquefier 3 is connected with an inter-tower inlet of the rectifying tower 4, and a CO2 outlet of the tower bottom reboiler 6 is connected with a CO2 inlet of the subcooler 7.
According to the circulation direction of the gas-phase cold source of the Freon refrigerator 1, the liquefying and purifying device comprises a tower bottom reboiler 6, a liquefier 3 and a refrigerant gas-liquid separation tank 8 which are sequentially connected, wherein a gas-phase outlet of the refrigerant gas-liquid separation tank 8 is connected with the Freon refrigerator 1.
The liquid-phase cold source outlet of the Freon refrigerator 1 is divided into three branches, one branch is connected with the tower top condenser 5, the other branch is connected with the subcooler 7, the product outlet of the tower top condenser 5 is connected with the precooler 2, the cold source outlet of the tower top condenser 5 is connected with the refrigerant gas-liquid separation tank 8, the outlet of the subcooler 7 is connected with the refrigerant gas-liquid separation tank 8, and the outlet of the liquefier 3 is connected with the refrigerant gas-liquid separation tank 8.
The liquid phase outlet of the refrigerant gas-liquid separation tank 8 is connected with the liquefier 3.
The CO2 impurity removing device comprises a primary hydrolysis desulfurization reactor 10, a zinc oxide desulfurization reactor 11, a secondary hydrolysis desulfurization reactor 12, a purified gas heat exchanger 13, a heater 14 and a dealkylation reactor 15 which are sequentially connected, wherein an outlet of the dealkylation reactor 15 is connected with the purified gas heat exchanger 13, and a CO2 purified gas outlet of the purified gas heat exchanger 13 is connected with a drying device 16.
The utility model also provides a method for purifying food-grade liquid carbon dioxide by adopting the purifying device system, which comprises the following steps:
(1) Carrying out desulfurization reaction, dealkylation reaction and drying treatment on the CO2 raw material gas in sequence to obtain CO2 purified gas, wherein the desulfurization reaction comprises primary hydrolysis desulfurization, zinc oxide desulfurization and secondary hydrolysis desulfurization which are carried out in sequence;
The temperature of the desulfurization reaction is 100-140 ℃ and the pressure is 2.3-3.0 MPaG, the catalyst used in the dealkylation reaction comprises a Pt-Pd noble metal catalyst, the temperature is 300-470 ℃, the pressure is 2.3-3.0 MPaG, the drying treatment is carried out by adopting a 4A molecular sieve, the temperature is 10-40 ℃, and the pressure is 2.3-3.0 MPaG;
The S content of the CO2 purified gas is less than or equal to 0.1ppm, the water content is less than or equal to 12ppm, and the hydrocarbon content is less than or equal to 30ppm;
(2) Sequentially liquefying, rectifying and purifying the CO2 purified gas obtained in the step (1) and supercooling to obtain the food-grade liquid carbon dioxide;
The liquefying process comprises pre-cooling and liquefying which are sequentially carried out, wherein the end temperature of the pre-cooling is 4-8 ℃, the end temperature of the liquefying process is-10-20 ℃, the temperature of rectifying and purifying is-10-20 ℃, the pressure is 2.2-2.5 MPaG, the supercooling temperature of the supercooling process is-30-23 ℃, and the pressure is 2-2.5 MPa.
Example 1
The embodiment provides a purification device system of food-grade liquid carbon dioxide, which comprises a CO2 impurity removal device shown in figure 2 and a CO2 purified gas liquefaction purification device shown in figure 1 which are connected;
The CO2 purified gas liquefaction and purification device comprises a Freon refrigerator 1 and liquefaction and purification equipment, wherein the Freon refrigerator 1 provides a cold source for the liquefaction and purification equipment;
According to the flowing direction of the CO2 purified gas, the liquefying and purifying device comprises a precooler 2, a liquefier 3, a rectifying tower 4, a subcooler 7 and a storage tank 9 which are sequentially connected.
The rectifying tower 4 comprises a tower top condenser 5 and a tower bottom reboiler 6, an outlet of the liquefier 3 is connected with an inter-tower inlet of the rectifying tower 4, and a CO2 outlet of the tower bottom reboiler 6 is connected with a CO2 inlet of the subcooler 7.
According to the circulation direction of the gas-phase cold source of the Freon refrigerator 1, the liquefying and purifying device comprises a tower bottom reboiler 6, a liquefier 3 and a refrigerant gas-liquid separation tank 8 which are sequentially connected, wherein a gas-phase outlet of the refrigerant gas-liquid separation tank 8 is connected with the Freon refrigerator 1.
The liquid-phase cold source outlet of the Freon refrigerator 1 is divided into three branches, one branch is connected with the tower top condenser 5, the other branch is connected with the subcooler 7, the product outlet of the tower top condenser 5 is connected with the precooler 2, the cold source outlet of the tower top condenser 5 is connected with the refrigerant gas-liquid separation tank 8, the outlet of the subcooler 7 is connected with the refrigerant gas-liquid separation tank 8, and the outlet of the liquefier 3 is connected with the refrigerant gas-liquid separation tank 8.
The liquid phase outlet of the refrigerant gas-liquid separation tank 8 is connected with the liquefier 3.
The CO2 impurity removing device comprises a primary hydrolysis desulfurization reactor 10, a zinc oxide desulfurization reactor 11, a secondary hydrolysis desulfurization reactor 12, a purified gas heat exchanger 13, a heater 14 and a dealkylation reactor 15 which are sequentially connected, wherein an outlet of the dealkylation reactor 15 is connected with the purified gas heat exchanger 13, and a CO2 purified gas outlet of the purified gas heat exchanger 13 is connected with a drying device 16.
Example 2
This embodiment provides a purification apparatus system for food grade liquid carbon dioxide, which differs from embodiment 1 only in that:
In the embodiment, the purified gas heat exchanger 13 in the CO2 impurity removing device is adjusted to be a methanol cooling device.
Example 3
This embodiment provides a purification apparatus system for food grade liquid carbon dioxide, which differs from embodiment 1 only in that:
The drying apparatus 16 in the CO2 impurity removal device is omitted in this embodiment.
Example 4
This embodiment provides a purification apparatus system for food grade liquid carbon dioxide, which differs from embodiment 1 only in that:
The freon refrigerator 1 in the CO2 purified gas liquefaction purifying device is adjusted to be a water chilling unit.
Comparative example 1
This comparative example provides a purification apparatus system for food-grade liquid carbon dioxide that differs from example 1 only in that:
the comparison example is characterized in that the CO2 purified gas liquefaction and purification device is adjusted to be a precooler and a liquefier which are sequentially connected.
Application example 1
The present application provides a method for purifying food grade liquid carbon dioxide using the purification apparatus system provided in embodiment 1, the purification method comprising the steps of:
(1) Carrying out desulfurization reaction, dealkylation reaction and drying treatment on the CO2 raw material gas in sequence to obtain CO2 purified gas, wherein the desulfurization reaction comprises primary hydrolysis desulfurization, zinc oxide desulfurization and secondary hydrolysis desulfurization which are carried out in sequence;
The temperature of the desulfurization reaction is 120 ℃, the pressure is 2.7MPaG, the catalyst used in the dealkylation reaction comprises a Pt-Pd noble metal catalyst, the temperature is 400 ℃, the pressure is 2.7MPaG, the drying treatment is carried out by adopting a 4A molecular sieve, the temperature is 25 ℃, and the pressure is 2.7MPaG;
The S content of the CO2 purified gas is less than or equal to 0.1ppm, the water content is less than or equal to 12ppm, and the hydrocarbon content is less than or equal to 30ppm;
(2) Sequentially liquefying, rectifying and purifying the CO2 purified gas obtained in the step (1) and supercooling to obtain the food-grade liquid carbon dioxide;
The liquefying process comprises pre-cooling and liquefying which are sequentially carried out, wherein the end temperature of the pre-cooling is 6 ℃, the end temperature of the liquefying process is-15 ℃, the temperature of rectifying and purifying is-15 ℃, the pressure is 2.4MPaG, and the supercooling temperature of the supercooling process is-26 ℃ and the pressure is 2.25MPa.
Application example 2
The present application provides a method for purifying food grade liquid carbon dioxide using the purification apparatus system provided in embodiment 1, the purification method comprising the steps of:
(1) Sequentially carrying out desulfurization reaction, dealkylation reaction and drying treatment on the CO2 raw gas to obtain CO2 purified gas, wherein the desulfurization reaction comprises sequentially carrying out primary hydrolysis desulfurization, zinc oxide desulfurization and secondary hydrolysis desulfurization;
The temperature of the desulfurization reaction is 100 ℃, the pressure is 3.0MPaG, the catalyst used in the dealkylation reaction comprises a Pt-Pd noble metal catalyst, the temperature is 300 ℃, the pressure is 3.0MPaG, the drying treatment is carried out by adopting a 4A molecular sieve, the temperature is 10 ℃, and the pressure is 3.0MPaG;
The S content of the CO2 purified gas is less than or equal to 0.1ppm, the water content is less than or equal to 12ppm, and the hydrocarbon content is less than or equal to 30ppm;
(2) Sequentially liquefying, rectifying and purifying the CO2 purified gas obtained in the step (1) and supercooling to obtain the food-grade liquid carbon dioxide;
The liquefying process comprises pre-cooling and liquefying which are sequentially carried out, wherein the end temperature of the pre-cooling is 4 ℃, the end temperature of the liquefying process is-20 ℃, the temperature of rectifying and purifying is-20 ℃, the pressure is 2.5MPaG, and the supercooling temperature of the supercooling process is-30 ℃ and the pressure is 2.5MPa.
Application example 3
The present application provides a method for purifying food grade liquid carbon dioxide using the purification apparatus system provided in embodiment 1, the purification method comprising the steps of:
(1) Carrying out desulfurization reaction, dealkylation reaction and drying treatment on the CO2 raw material gas in sequence to obtain CO2 purified gas, wherein the desulfurization reaction comprises primary hydrolysis desulfurization, zinc oxide desulfurization and secondary hydrolysis desulfurization which are carried out in sequence;
The temperature of the desulfurization reaction is 140 ℃, the pressure is 2.3MPaG, the catalyst used in the dealkylation reaction comprises a Pt-Pd noble metal catalyst, the temperature is 470 ℃, the pressure is 2.3MPaG, the drying treatment is carried out by adopting a 4A molecular sieve, the temperature is 40 ℃, and the pressure is 2.3MPaG;
The S content of the CO2 purified gas is less than or equal to 0.1ppm, the water content is less than or equal to 12ppm, and the hydrocarbon content is less than or equal to 30ppm;
(2) Sequentially liquefying, rectifying and purifying the CO2 purified gas obtained in the step (1) and supercooling to obtain the food-grade liquid carbon dioxide;
The liquefying process comprises pre-cooling and liquefying which are sequentially carried out, wherein the end temperature of the pre-cooling is 8 ℃, the end temperature of the liquefying process is-10 ℃, the temperature of rectifying and purifying is-10 ℃, the pressure is 2.2MPaG, and the supercooling temperature of the supercooling process is-23 ℃ and the pressure is 2MPa.
As can be seen from comprehensive analysis application examples 1-3, the device system provided by the utility model is used for treating CO2 raw material gas, the purity of the obtained liquid carbon dioxide is more than or equal to 99.9%, the impurity content is lower than 0.1%, and the requirements of food-grade carbon dioxide are met.
Application example 4
The present application example provides a method for purifying food-grade liquid carbon dioxide using the purification apparatus system provided in example 1, which differs from application example 1 only in that:
The application example adjusts the temperature of rectification purification in the step (2) to be-30 ℃.
Application example 5
The present application example provides a method for purifying food-grade liquid carbon dioxide using the purification apparatus system provided in example 1, which differs from application example 1 only in that:
The application example adjusts the temperature of rectification purification in the step (2) to be-5 ℃.
Application example 6
The present application example provides a method for purifying food-grade liquid carbon dioxide using the purification apparatus system provided in example 1, which differs from application example 1 only in that:
The application example adjusts the pressure of the rectification purification in the step (2) to be 1.8MPaG.
Application example 7
The present application example provides a method for purifying food-grade liquid carbon dioxide using the purification apparatus system provided in example 1, which differs from application example 1 only in that:
The application example adjusts the pressure of the rectification purification in the step (2) to be 3.2MPaG.
As can be seen from comprehensive analysis of application examples 4-7, application examples 4-7 differ from application example 1 only in the process parameters of the rectification and purification process, and adjustment of the process parameters of the rectification and purification process can result in reduction of the purity of liquid carbon dioxide, even in the purity of the obtained carbon dioxide being lower than 99.9%, and cannot meet the requirements of food-grade carbon dioxide, so that reasonable selection of the process parameters of the rectification and purification process is one of important factors affecting the quality of carbon dioxide.
Application example 8
This application example provides a method of purifying food grade liquid carbon dioxide using the purification apparatus system provided in example 2, the purification method being the same as application example 1.
As can be seen from the comprehensive analysis of application examples 1 and 8, when the purified gas heat exchanger in the CO2 impurity removal device is adjusted to be a methanol cooling device, methanol needs to be supplied at any time to provide energy for the device, so that the energy produced by the device system is seriously wasted, and the reaction process is affected due to insufficient supply of the methanol.
Application example 9
The present application example provides a method for purifying food-grade liquid carbon dioxide using the purification apparatus system provided in example 3, which differs from application example 1 only in that:
the drying process described in step (1) is omitted in this application example.
As is clear from the comprehensive analysis of application examples 1 and 9, when the drying apparatus is omitted, too high a water content of the obtained CO2 purge gas may cause solidification of water in the liquefied CO2, cause clogging of equipment, and affect the separation effect of the product.
Application example 10
This application example provides a method of purifying food grade liquid carbon dioxide using the purification apparatus system provided in example 4, the purification method being the same as application example 1.
As can be seen from the comprehensive analysis of application example 1 and application example 10, application example 10 differs from application example 1 only in the difference of the refrigerating unit, and when the cooling water unit is used for heat exchange, the lowest temperature provided by the chilled water cannot meet the low temperature requirement in the subsequent rectification or supercooling process, and the purification and liquefaction of CO2 are affected.
Comparative application example 1
The present comparative application example provides a purification method of food grade liquid carbon dioxide using the purification apparatus system provided in comparative example 1, which differs from application example 1 only in that:
The comparative application example adjusts the step (2) to carry out liquefaction treatment on the CO2 purified gas obtained in the step (1), and omits the rectification purification and supercooling treatment process.
As can be seen from the comprehensive analysis application example 1 and the comparative application example 1, the rectification and purification process can further remove the light components in the carbon dioxide gas, and omitting the rectification and purification process can result in the reduction of the purity of the liquid carbon dioxide, which cannot meet the requirements of the food-grade carbon dioxide.
In summary, in the device system provided by the utility model, the light components in the CO2 purified gas can be effectively removed by coupling the rectifying tower and the refrigerating equipment, so that the heat exchange in the CO2 purified gas liquefaction and purification process is realized, the refrigeration and liquefaction of carbon dioxide are effectively realized, and the liquid storage of food-grade carbon dioxide is realized.
The applicant declares that the above is only a specific embodiment of the present utility model, but the scope of the present utility model is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present utility model disclosed by the present utility model fall within the scope of the present utility model and the disclosure.