CN102410704B - Production method of food grade liquid carbon dioxide product for recycling resurgent gases - Google Patents

Abstract

The invention relates to a production method of carbon dioxide, and specifically discloses a production method of a food-grade liquid carbon dioxide product that recovers regeneration gas, comprising the following steps: (1) Compression process; (2) Dehydrocarbon process; (3) Purification process, wherein, The step of heating and desorbing impurities is used to heat the adsorbent, so that the impurities adsorbed by the adsorbent are heated and desorbed, and the adsorbent obtains a fully regenerated air flow and the step of cooling the adsorbent is used to return the air flow of the cooled adsorbent to the carbon dioxide raw material gas containing impurities; ( 4) Liquefaction process; (5) Distillation purification process. The production method of the food-grade liquid carbon dioxide product of the present invention not only greatly reduces the methane and ethylene content of the food-grade liquid carbon dioxide product, which is lower than the international standard, but also makes the utilization rate of the carbon dioxide raw material gas containing impurities Greatly improved, from 76% to 88%, increased the output of food-grade liquid carbon dioxide products, reduced production costs, and greatly reduced greenhouse gas emissions.

Description

A kind of production method of the food-grade liquid carbon dioxide product that recycles regeneration gas

technical field

The invention generally relates to a production method of carbon dioxide, in particular to a production method of a food-grade liquid carbon dioxide product that recovers regeneration gas.

Background technique

Fig. 3 shows the flow process of a kind of production method of food-grade liquid carbon dioxide product, comprises the following steps:

(1) Compression process 30

The carbon dioxide raw material gas containing mechanical water, methane, ethylene, benzene and other impurities with a carbon dioxide content of about 99.2% from outside the boundary area is washed with water and precooled by the precooler 10, and the mechanical water is removed by the first water separator 20 before entering In the compression process 30, the pressure is increased to 0.1-0.35Mpa by the first-stage compressor 31, the pressure is increased by the second-stage compressor 32 to 0.8-1.2MPa and the pressure is increased by the third-stage compressor 33 to 2.3-2.8MPa. The temperature of the outgoing carbon dioxide gas containing impurities such as methane, ethylene, and benzene is 110-120°C, and it enters the heat exchanger 130, and is regulated with the regulated Valve 1014 throttles and expands the gas mixture decompressed to 0.05MPa again and the flash gas discharged from the spherical tank 112. The confluent airflow formed after confluence is carried out in the heat exchanger 130, and then cooled and cooled by the water cooler 60. The second water separator 70 separates the mechanical water, and then sends it to the purification process 80 .

(2) Purification process 80

Using the temperature swing adsorption process, multiple purifiers switch to work. When one or several purifiers 81 are in the adsorption state, the other or several purifiers 82 are in the regeneration state, and the remaining one or several purifiers 83 Then it is in the standby state, absorbing impurities at normal temperature and desorbing impurities at high temperature. Water vapor (PPM level) and trace benzene (PPB level) impurities are selectively adsorbed to purify the carbon dioxide gas containing methane, ethylene, benzene and other impurities from the second water separator 70 .

① Adsorption

The carbon dioxide gas containing methane, ethylene, benzene and other impurities from the second water separator 70 enters the adsorption tower from the bottom of the purifier 81, which is usually called an adsorption tower, and is discharged from the top of the adsorption tower. In the adsorption tower, the adsorbent can effectively adsorb traces of water vapor and benzene, so that the indicators of water and benzene in the gas at the outlet of the adsorption tower reach the corresponding design indicators or specified standards, and then sent to the liquefaction process 90 and distillation purification process 100. After the adsorbent has been adsorbed for a certain period of time, it is expected that the adsorbent will stop adsorption when it is close to saturation.

②Reverse pressure release

After the adsorption step is completed, the carbon dioxide gas containing traces of methane, ethylene and other impurities in the adsorption tower is flow-limited and pressure-relieved against the direction of adsorption, and discharged out of the purifier 81. After the end, the pressure in the adsorption tower is close to normal pressure.

③Heating and desorption of impurities

The gas mixture containing a small amount of uncondensed carbon dioxide gas and a large amount of methane and ethylene discharged from the top of the distillation purification tower 101 in the distillation purification process 100, after being throttled and expanded by the regulating valve 1013, the temperature decreases, and enters the heat exchanger 1012 at the top of the distillation purification tower 101 The shell side exchanges heat with the flash steam rising in the tube side of the heat exchanger 1012. Part of the uncondensed carbon dioxide gas in the flash steam is condensed and falls into the bottom of the distillation purification tower 101, and the rest becomes the above-mentioned gas mixture from the distillation The gas mixture is discharged from the top of the purification tower 101, and the gas mixture is throttled and expanded by the regulating valve 1013, and the temperature decreases, and enters the shell side of the heat exchanger 1012 on the upper part of the distillation purification tower 101, and the gas mixture coming out of the shell side of the heat exchanger 1012 passes through the regulating valve 1014 section After the flow is expanded, the pressure is reduced to 0.05MPa again, and a part of the confluent airflow formed after merging with the flash gas discharged from the spherical tank 112 enters the heat exchanger 130, and the temperature coming out from the three-stage compressor 33 is 110-120°C The carbon dioxide gas containing impurities such as methane, ethylene, and benzene enters the electric heater 140 after heat exchange and is heated to 180-235°C, and then enters the purifier 81, that is, the adsorption tower, which is in the process of heating and desorbing impurities, and reverses the adsorption process. The adsorbent is flushed in the direction, so that the impurities adsorbed by the adsorbent are heated and desorbed, the adsorbent is fully regenerated, and then discharged as waste gas.

④Cooling adsorbent

After the step of heating and desorbing impurities is completed, the impurities such as water and benzene adsorbed by the adsorbent in the purifier 81 are almost completely desorbed. At this time, another part of the combined air flow is directly sent to the purifier 81, and the adsorbent in the purifier 81 Cool down to ≤25°C.

⑤Purifier charging

Purifier 81 is pressurized to an adsorption pressure of 2.3-2.8 MPa by using carbon dioxide gas containing traces of impurities such as methane and ethylene from a part of the purifier 82, which has been switched from the regeneration state to the adsorption state, and is usually called an adsorption tower. , ready to enter the next adsorption.

(3) Liquefaction process 90

Part of the purified carbon dioxide gas containing impurities such as methane and ethylene from the purification process 80 enters the reboiler 1011 of the distillation purification tower 101 of the distillation purification process 100 through an orifice flowmeter 1015, which is usually called a tower coil. It fully provides the heat source required for the distillation and purification of the product liquid carbon dioxide, and is discharged from the outlet of the reboiler 1011, which is usually called a tower coil, and is mixed with the purified gas containing impurities such as methane and ethylene from the purification process 80 The other part of the carbon dioxide gas, after the other part flows out from the regulating valve 1016 controlled by the orifice flowmeter 1015, the two parts are merged together and enter the first evaporative condenser 91 of the liquefaction process 90 for liquefaction. The cold source of the first evaporative condenser 91 in the liquefaction process 90 is liquid ammonia. In the first evaporative condenser 91, the carbon dioxide gas containing impurities such as methane and ethylene fully exchanges heat with the liquid ammonia. In the first evaporative condenser 91 The liquid ammonia liquid level of the liquid ammonia is precisely controlled by a regulating valve, so that most of the carbon dioxide gas is fully liquefied and becomes liquid carbon dioxide at -23--24°C, and then sent to the distillation purification process 100.

(4) distillation purification process 100

From the first evaporative condenser 91 of the liquefaction process 90, the liquefied carbon dioxide containing uncondensed carbon dioxide gas and impurities such as methane and ethylene is sprayed into the tower still of the distillation purification tower 101 of the distillation purification process 100 through the nozzle 1021 for distillation. Purification, methane, ethylene and other impurities and uncondensed carbon dioxide gas are distilled from the liquefied carbon dioxide, which is called flash gas, and the product liquid carbon dioxide with a temperature of -21 ~ -23 ° C is obtained in the lower part of the tower kettle. The flash gas rises from the bottom of the tower and contacts with the mist liquid carbon dioxide sprayed from the nozzle 1021. Part of the uncondensed carbon dioxide gas in the flash gas is condensed and falls into the bottom of the tower; the flash gas continues to rise and enters the upper part of the distillation purification tower 101 The tube side of the heat exchanger 1012 exchanges heat with the gas mixture that enters the shell side of the heat exchanger 1012 after being throttled by the regulating valve 1013 and the expansion temperature is lowered. Part of the uncondensed carbon dioxide gas in the flash gas is condensed and falls into the tower kettle. The flash gas leaves the tube side of the heat exchanger 1012 and becomes a gas mixture containing a small amount of uncondensed carbon dioxide gas and a large amount of methane and ethylene, and is discharged from the top of the distillation purification tower 101 in the distillation purification process 100 . Part of the purified carbon dioxide gas from the purification process 80 with a temperature of 28-32 °C containing traces of methane, ethylene and other impurities enters the distillation purification tower 101 of the distillation purification process 100 through the orifice flowmeter 1015, which is usually called the tower kettle. The inlet of the reboiler 1011 of the coil fully provides the heat source required for the distillation and purification of the product liquid carbon dioxide, and it is discharged from the outlet of the reboiler 1011, which is usually called a tower coil, and the discharge temperature is -9 ~ -11°C, which is the same as Another part of the purified carbon dioxide gas containing traces of methane, ethylene and other impurities at a temperature of 28-32°C from the purification process 80, after the other part flows out from the regulating valve 1016 controlled by the orifice flowmeter 1015, the The two parts are merged together and enter the first evaporative condenser 91 of the liquefaction process 90 for liquefaction.

(5) supercooling process 110

The product liquid carbon dioxide through distillation purification in the distillation purification tower 101 tower kettle of distillation purification process 100 is sent to the second evaporative condenser 111 of subcooling process 110, and the cold source of the second evaporative condenser 111 of supercooling process 110 is For liquid ammonia, in the second evaporative condenser 111, the temperature of the product liquid carbon dioxide is further reduced, and the product liquid carbon dioxide whose temperature is further lowered is sent to the product liquid carbon dioxide storage tank 112 for storage through a program-controlled valve.

The production method of food-grade liquid carbon dioxide product shown in Fig. 3 has following shortcoming:

In the production method of the food-grade liquid carbon dioxide product shown in Figure 3, (2) in the purification process 80 (3) the step of heating and desorbing impurities makes the impurities adsorbed by the adsorbent be heated and desorbed by the heated air flow used for desorption and (2) the purification process 80 In the ④ step of cooling the adsorbent, the cooling gas used for cooling the adsorbent comes from the shell side of the heat exchanger 1012 on the upper part of the distillation purification tower 101 in the distillation purification process 100, and then the pressure is reduced to The 0.05MPa gas mixture and the flash gas discharged from the spherical tank 112 are combined to form a confluent airflow. The confluent airflow is vented after ③ heating and desorbing impurities step and ④ cooling adsorbent step. However, the vented gas It contains a large amount of carbon dioxide, which not only causes a huge waste of raw material gas, but also emits a large amount of greenhouse gases into the atmosphere.

In addition, in the production method of the food-grade liquid carbon dioxide product shown in Figure 3, the purification process 80 is carried out after the three-stage compression of the compression process 30, and the outlet pressure of the three-stage compressor 33 is as high as 2.3-2.8MPa, which makes the purification The equipment, instruments, pipelines and adsorbents in process 80 all work under relatively high pressure. The high pressure resistance level proposed for these equipment, instruments, pipelines and adsorbents increases the cost input and reduces the service life , increasing security risks.

Contents of the invention

The present invention provides a production method for food-grade liquid carbon dioxide products that recover regenerated gas.

A kind of production method of the food-grade liquid carbon dioxide product that reclaims regeneration gas provided by the present invention comprises the following steps:

(1) Compression process

Mix the carbon dioxide raw material gas containing impurities and oxygen with a slight excess of chemical reaction, and return from the purification process to heat the adsorbent, so that the impurities adsorbed by the adsorbent are heated and desorbed, and the adsorbent is fully regenerated. Or return from the purification process The airflow used to cool the adsorbent passes through the water separator to remove mechanical water and then enters the compression process. The first-stage compressor boosts the pressure to 0.1-0.35Mpa, the second-stage compressor boosts the pressure to 0.8-1.2MPa and the third-stage compressor 33 boosted to 2.3-2.8MPa, and then sent to the dehydrogenation process;

(2) Dehydrogenation process

The impurity-containing carbon dioxide gas and slightly excess oxygen from the chemical reaction from the compression process enter the dehydrogenation process. In the dehydrogenation reactor, the methane and ethylene among the impurities and the slightly excess oxygen from the chemical reaction are processed at a temperature of 480-520 ° C and a pressure of . 2.3 ~ 2.8MPa, the active components are platinum and palladium and the carrier is alumina catalyst, a chemical reaction occurs to generate carbon dioxide and water, remove methane and ethylene in the carbon dioxide gas containing impurities, and then send it to the purification process;

(3) Purification process

Using the temperature swing adsorption process, multiple purifiers switch to work. When one or several purifiers are in the adsorption state, the other or several purifiers are in the regeneration state. The impurities are adsorbed at room temperature and desorbed at high temperature. The alumina and silica gel adsorbents in the purifier can remove trace water vapor (PPM grade) and trace benzene (PPB grade) impurities in carbon dioxide gas containing trace methane, ethylene, oxygen, benzene and water vapor impurities from the dehydrogenation process Selective adsorption, to purify the carbon dioxide gas containing trace methane, ethylene, oxygen, benzene and water vapor impurities from the dehydrogenation process, and then send it to the liquefaction process and distillation purification process;

In the step of heating and desorbing impurities, it is used to heat the adsorbent, so that the impurities adsorbed by the adsorbent are heated and desorbed, and the gas flow that is fully regenerated by the adsorbent is returned to the carbon dioxide raw material gas containing impurities;

In the step of cooling the adsorbent, the gas stream used for cooling the adsorbent is returned to the carbon dioxide feed gas containing impurities;

(4) Liquefaction process

A part of the impurity-containing carbon dioxide gas from the purification process enters the inlet of the reboiler of the distillation purification tower in the distillation purification process through the orifice flowmeter, which is usually called the tower coil, and fully provides the heat source required for the distillation and purification of the product liquid carbon dioxide. , discharged from the outlet of the reboiler, and another part of carbon dioxide gas containing impurities from the purification process, after the other part flows out from the regulating valve controlled by the orifice flowmeter, the two parts merge together and enter The evaporative condenser in the liquefaction process is liquefied, and most of the carbon dioxide gas containing impurities is liquefied, and then sent to the distillation purification process together with uncondensed carbon dioxide gas and trace amounts of methane, ethylene and oxygen;

(5) Distillation purification process

The liquefied carbon dioxide containing uncondensed carbon dioxide gas and trace amounts of methane, ethylene and oxygen from the liquefaction process enters the distillation purification column of the distillation purification process for distillation and purification. Impurities such as methane, ethylene and oxygen and uncondensed carbon dioxide gas Distilled from the carbon dioxide, called flash gas, the product liquid carbon dioxide is obtained in the lower part of the tower kettle.

Compared with the production method of the food-grade liquid carbon dioxide product shown in Figure 3, the production method of the food-grade liquid carbon dioxide product that reclaims regeneration gas of the present invention, increases dehydrogenation process between compression process and purification process, simultaneously purifies process The step of heating and desorbing impurities in is used to heat the adsorbent, so that the impurities adsorbed by the adsorbent are heated and desorbed, and the adsorbent gets a fully regenerated gas flow and the step of cooling the adsorbent is used to cool the gas flow of the adsorbent to return to the carbon dioxide raw gas containing impurities , together with the impurity-containing carbon dioxide feed gas, pass through the water separator to remove mechanical water and then enter the compression process, and then send it to the dehydrogenation process to remove methane and ethylene in the impurity-containing carbon dioxide gas, which not only makes the methane of the food-grade liquid carbon dioxide product The content of ethylene and ethylene is greatly reduced, which is lower than the international standard, and because the regeneration gas of the purification tower is recovered, the utilization rate of the carbon dioxide raw material gas containing impurities is greatly improved, from 76% to 88%, and the output of food-grade liquid carbon dioxide products is increased. The production cost is reduced, and the emission of greenhouse gases is greatly reduced.

Beneficially, the carbon dioxide gas containing impurities and a slight excess of oxygen from the compression step first enters the dehydrocarbonation preheater of the dehydrocarbonation step, then passes through the dehydrocarbonation heater, and finally enters the dehydrocarbonation reactor.

Beneficially, the dehydrocarbon preheater is a shell-and-tube heat exchanger, and the impurity-containing carbon dioxide gas and slightly excess oxygen from the compression process first enter the tube side of the dehydrocarbon preheater of the dehydrocarbon process, from the dehydrocarbon reactor The high-temperature gas that comes out returns to the shell side of the dehydrocarbon preheater.

The present invention provides another method for producing food-grade liquid carbon dioxide products that recover regenerated gas.

Another kind of production method of the food grade liquid carbon dioxide product that reclaims regeneration gas provided by the present invention comprises the following steps:

(1) The first compression process

Mix the carbon dioxide raw material gas containing impurities and oxygen with a slight excess of chemical reaction, and return from the purification process to heat the adsorbent, so that the impurities adsorbed by the adsorbent are heated and desorbed, and the adsorbent is fully regenerated. Or return from the purification process The airflow used to cool the adsorbent passes through the water separator to remove mechanical water and then enters the compression process. It is boosted to 0.1-0.35MPa by the first-stage compressor and 0.8-1.2MPa by the second-stage compressor, and then sent to the degasser. hydrocarbon process;

(2) Dehydrogenation process

The impurity-containing carbon dioxide gas and slightly excess oxygen from the chemical reaction from the first compression process enter the dehydrogenation process. In the dehydrogenation reactor, the methane and ethylene among the impurities and the slightly excess oxygen from the chemical reaction are heated at a temperature of 480-520°C. The pressure is 0.8 ~ 1.2MPa, the active components are platinum and palladium, and the carrier is alumina. A chemical reaction occurs under the action of a catalyst to generate carbon dioxide and water, remove methane and ethylene in the carbon dioxide gas containing impurities, and then send it to purification process;

(3) Purification process

Using the temperature swing adsorption process, multiple purifiers switch to work. When one or several purifiers are in the adsorption state, the other or several purifiers are in the regeneration state. The impurities are adsorbed at room temperature and desorbed at high temperature. The alumina and silica gel adsorbents in the purifier can remove trace water vapor (PPM grade) and trace benzene (PPB grade) impurities in carbon dioxide gas containing trace methane, ethylene, oxygen, benzene and water vapor impurities from the dehydrogenation process Selective adsorption, to purify the carbon dioxide gas containing trace methane, ethylene, oxygen, benzene and water vapor impurities from the dehydrogenation process, and then send it to the second compression process;

In the step of heating and desorbing impurities, it is used to heat the adsorbent, so that the impurities adsorbed by the adsorbent are heated and desorbed, and the gas flow that is fully regenerated by the adsorbent is returned to the carbon dioxide raw material gas containing impurities;

In the step of cooling the adsorbent, the gas stream used for cooling the adsorbent is returned to the carbon dioxide feed gas containing impurities;

(4) Second compression process

The impurity-containing carbon dioxide gas from the purification process enters the second compression process, and is boosted to 2.3-2.8MPa by the compressor of the second compression process, and then sent to the liquefaction process and distillation purification process;

(5) Liquefaction process

A part of the impurity-containing carbon dioxide gas from the second compression process enters the inlet of the reboiler of the distillation purification tower in the distillation purification process through the orifice flowmeter, which is usually called the tower coil, and fully provides the liquid carbon dioxide distillation and purification of the product. The heat source of the reboiler is discharged from the outlet of the reboiler, and another part of the impurity-containing carbon dioxide gas from the second compression process is merged after the other part flows out of the regulating valve controlled by the orifice flowmeter Together, enter the evaporative condenser of the liquefaction process for liquefaction, most of the carbon dioxide gas containing impurities is liquefied, and then sent to the distillation purification process together with uncondensed carbon dioxide gas and trace amounts of methane, ethylene and oxygen;

(6) Distillation purification process

The liquefied carbon dioxide containing uncondensed carbon dioxide gas and trace amounts of methane, ethylene and oxygen from the liquefaction process enters the distillation purification column of the distillation purification process for distillation and purification. Impurities such as methane, ethylene and oxygen and uncondensed carbon dioxide gas Distilled from the carbon dioxide, called flash gas, the product liquid carbon dioxide is obtained in the lower part of the tower kettle.

The production method of the food-grade liquid carbon dioxide product shown in Figure 2 of the present invention changes the compression process in the production method of the food-grade liquid carbon dioxide product shown in Figure 1 of the present invention to the first one shown in Figure 2 of the present invention The compression process and the second compression process, the first compression process is similar to the compression process in the production method of the food-grade liquid carbon dioxide product shown in Figure 1, and is located before the dehydrogenation process and the purification process, but the maximum output pressure only reaches 0.8-1.2 MPa, which is significantly lower than the maximum output pressure of 2.3-2.8 MPa in the compression process in the production method of food-grade liquid carbon dioxide products shown in Figure 1. The second compression process is located after the dehydrocarbon process and purification process, and the output pressure reaches 2.3-2.8 MPa. MPa, which makes the dehydrogenation process and purification process operate at a pressure of 0.8-1.2 MPa, rather than operating at a pressure of 2.3-2.8 MPa like the purification process in the production method of food-grade liquid carbon dioxide products shown in Figure 1 In this way, the equipment, instruments, pipelines, catalysts and adsorbents in the dehydrogenation process and purification process have a low pressure resistance level, which reduces cost investment, prolongs the service life, and reduces potential safety hazards.

Beneficially, the carbon dioxide gas containing impurities and a slight excess of oxygen from the first compression step first enters the dehydrocarbonation preheater of the dehydrocarbonation step, then passes through the dehydrocarbonation heater, and finally enters the dehydrocarbonation reactor.

Beneficially, the dehydrocarbon preheater is a shell-and-tube heat exchanger, and the impurity-containing carbon dioxide gas and slightly excess oxygen from the first compression process first enter the tube side of the dehydrocarbon preheater of the dehydrocarbon process, from the dehydrocarbon The high-temperature gas from the reactor returns to the shell side of the dehydrocarbon preheater.

Description of drawings

Fig. 1 is the flow chart of the first embodiment of the production method of the food-grade liquid carbon dioxide product of recovery gas of the present invention;

Fig. 2 is the flow chart of the second embodiment of the production method of the food-grade liquid carbon dioxide product of recovery gas of the present invention;

Fig. 3 is a flowchart of a production method of a food-grade liquid carbon dioxide product in the background technology.

Detailed ways

The specific embodiment of the production method of the food-grade liquid carbon dioxide product of the recovery gas of the present invention will be described in detail below with reference to the accompanying drawings, and the characteristics and advantages of the production method of the food-grade liquid carbon dioxide product of the recovery gas of the present invention will become more obvious.

Referring to Fig. 1, the first embodiment of the production method of the food-grade liquid carbon dioxide product that reclaims regeneration gas of the present invention, comprises the following steps:

(1) Compression process 30

The carbon dioxide raw material gas containing mechanical water, methane, ethylene, benzene and other impurities with a carbon dioxide content of about 99.2% from outside the boundary area is washed with water, and the chemical reaction that is mediated by the regulating valve 2 controlled by the orifice flowmeter 1 is slightly adjusted. The excess oxygen is mixed with the gas flow returned from the purification process 80 to heat the adsorbent, the impurities adsorbed by the adsorbent are heated and desorbed, and the adsorbent is fully regenerated, or the gas flow returned from the purification process 80 to cool the adsorbent Enter the pre-cooler 10 for pre-cooling, go through the first water separator 20 to remove the mechanical water, and then enter the compression process 30, the pressure is raised to 0.1-0.35Mpa by the first-stage compressor 31, and the pressure is raised to 0.8-1.2MPa by the second-stage compressor 32 and three-stage compressor 33 to boost the pressure to 2.3-2.8MPa, and the temperature of the carbon dioxide gas and oxygen containing impurities such as methane, ethylene, benzene, etc. that come out from the three-stage compressor 33 is 110-120°C, and then sent to the dehydrogenation process 50 .

(2) Dehydrogenation process 50

The carbon dioxide gas and oxygen containing methane, ethylene, benzene and other impurities from the compression process 30 first enter the dehydrogenation preheater 51 to preheat to 215-225°C, then pass through the dehydrogenation heater 52 to heat to 480-520°C, and finally enter the Dehydrogenation Reactor 53. In the dehydrogenation reactor 53, methane, ethylene and oxygen in the carbon dioxide gas containing impurities such as methane, ethylene and benzene undergo a chemical reaction under the action of a catalyst whose active components are platinum and palladium and whose carrier is alumina under high temperature and pressure. This produces carbon dioxide and water. When the dehydrocarbon preheater 51 is a shell and tube heat exchanger, the high-temperature gas from the dehydrocarbon reactor 53 returns to the shell side of the dehydrocarbon preheater 51, and the gas containing methane and ethylene from the compression process 30 in the tube side After exchanging heat with carbon dioxide gas of impurities such as benzene, benzene, etc., it first exchanges heat with the following confluent air flow through the heat exchanger 130, then cools down through the water cooler 60 and separates the mechanical water by the second water separator 70, and then enters the purification process 80. Through the dehydrogenation process 50, most of the methane and ethylene in the carbon dioxide gas containing impurities such as methane, ethylene, and benzene from the compression process 30 are converted into carbon dioxide and water. Therefore, the carbon dioxide gas entering the purification process 80 contains incomplete Removed traces of methane and ethylene, traces of oxygen and newly generated water vapor that cannot be separated by the second water separator 70. The dehydrocarbon heater 52 may be an electric heater. The dehydrogenation reactor 53 may have the structure of a general catalytic reactor.

(3) Purification process 80

Using the temperature swing adsorption process, multiple purifiers switch to work. When one or several purifiers 81 are in the adsorption state, the other or several purifiers 82 are in the regeneration state, and the remaining one or several purifiers 83 Then it is in a standby state, absorbing impurities at normal temperature and desorbing impurities at high temperature. The alumina and silica gel adsorbents packed in the purifier are used to treat impurities such as trace methane, ethylene, oxygen, benzene and water vapor from the second water separator 70. The trace water vapor (PPM grade) and trace benzene (PPB grade) impurities in the carbon dioxide gas are selectively adsorbed, and the carbon dioxide gas containing trace methane, ethylene, oxygen, benzene and water vapor and other impurities from the second water separator 70 is selectively adsorbed. Purify.

① Adsorption

The carbon dioxide gas containing trace methane, ethylene, oxygen, benzene, water vapor and other impurities from the second water separator 70 enters the adsorption tower from the bottom of the purifier 81, which is usually called an adsorption tower, and is discharged from the top of the adsorption tower. In the adsorption tower, the adsorbent can effectively adsorb traces of water vapor and benzene, so that the indicators of water and benzene in the gas at the outlet of the adsorption tower reach the corresponding design indicators or specified standards, and then sent to the liquefaction process 90 and distillation purification process 100. After the adsorbent has been adsorbed for a certain period of time, it is expected that the adsorbent will stop adsorption when it is close to saturation.

②Reverse pressure release

After the adsorption step is completed, the carbon dioxide gas containing trace methane, ethylene, oxygen and other impurities in the adsorption tower is discharged out of the purifier 81 by flow restriction and pressure relief against the adsorption direction. After the end, the pressure in the adsorption tower is close to normal pressure.

③Heating and desorption of impurities

The gas mixture containing a small amount of uncondensed carbon dioxide gas and a large amount of methane, ethylene, and oxygen discharged from the top of the distillation purification tower 101 in the distillation purification process 100, after being throttled and expanded by the regulating valve 1013, the temperature decreases, and enters the heat exchange at the top of the distillation purification tower 101 The shell side of the heat exchanger 1012 exchanges heat with the flash steam rising in the tube side of the heat exchanger 1012. Part of the uncondensed carbon dioxide gas in the flash steam is condensed and falls into the bottom of the distillation purification tower 101, and the rest becomes the above-mentioned gas mixture Discharged from the top of the distillation and purification tower 101, the gas mixture is throttled and expanded by the regulating valve 1013, and the temperature decreases, and enters the shell side of the heat exchanger 1012 on the upper part of the distillation and purification tower 101, and the gas mixture coming out of the shell side of the heat exchanger 1012 passes through the regulating valve After throttling and expansion at 1014, the pressure is lowered to 0.05MPa again, and part of the confluent airflow formed after being merged with the flash gas discharged from the spherical tank 112 enters the heat exchanger 130, and is combined with the dehydrocarbon preheater 51 from the dehydrocarbon process 50 The carbon dioxide gas containing trace impurities such as methane, ethylene, oxygen, benzene, and water vapor enters the electric heater 140 after heat exchange and is heated to 180-235°C, and then enters the purifier 81, which is the adsorption tower, which is in the process of heating and desorbing impurities. Inside, the adsorbent is washed against the direction of adsorption, so that the impurities adsorbed by the adsorbent are heated and desorbed, and the adsorbent is fully regenerated, and then the carbon dioxide containing impurities such as mechanical water, methane, ethylene, and benzene from outside the boundary area is returned. The content of carbon dioxide is about 99.2% of the carbon dioxide in the raw gas.

④Cooling adsorbent

After the step of heating and desorbing impurities is completed, the impurities such as water and benzene adsorbed by the adsorbent in the purifier 81 are almost completely desorbed. At this time, another part of the combined air flow is directly sent to the purifier 81, and the adsorbent in the purifier 81 Cool down to ≤25°C, and then return to the carbon dioxide raw material gas containing mechanical water, methane, ethylene, benzene and other impurities with a carbon dioxide content of about 99.2%.

⑤Purifier charging

Purifier 81 is pressurized to an adsorption pressure of 2.3 to 2.3 by using carbon dioxide gas containing trace methane, ethylene, oxygen and other impurities from a part of the purifier 82, which is usually called an adsorption tower, which is switched from a regeneration state to an adsorption state. 2.8MPa, ready to enter the next adsorption.

(4) Liquefaction process 90

Part of the carbon dioxide gas containing impurities such as trace methane, ethylene and oxygen from the purification process 80 enters the inlet of the reboiler 1011 of the distillation purification column 101 of the distillation purification process 100 through an orifice flowmeter 1015, which is usually called a column coil. , fully provide the heat source required for the distillation and purification of the product liquid carbon dioxide, and discharge from the outlet of the reboiler 1011, which is usually called the tower coil, and the purified product containing traces of methane, ethylene, oxygen and other impurities from the purification process 80 The other part of the carbon dioxide gas, after the other part flows out from the regulating valve 1016 controlled by the orifice flowmeter 1015, the two parts merge together and enter the first evaporative condenser 91 of the liquefaction process 90 for liquefaction. The cold source of the first evaporative condenser 91 in the liquefaction process 90 is liquid ammonia. In the first evaporative condenser 91, the carbon dioxide gas containing traces of methane, ethylene, oxygen and other impurities fully exchanges heat with the liquid ammonia, and the first evaporative condensation The liquid ammonia liquid level in the tank 91 is precisely controlled by a regulating valve, so that most of the carbon dioxide gas is fully liquefied and becomes liquid carbon dioxide at -23--24°C, and then sent to the distillation purification process 100 .

(5) distillation purification process 100

From the first evaporative condenser 91 of the liquefaction process 90, the liquefied carbon dioxide containing uncondensed carbon dioxide gas and traces of impurities such as methane, ethylene, and oxygen enters the tower of the distillation purification tower 101 of the distillation purification process 100 through spray nozzle 1021 mist spray Distillation and purification are carried out in the still, and impurities such as methane, ethylene and oxygen and uncondensed carbon dioxide gas are distilled from the liquefied carbon dioxide, which is called flash gas, and the product liquid carbon dioxide with a temperature of -21 ~ -23°C is obtained in the lower part of the tower kettle. The flash gas rises from the bottom of the tower and contacts with the mist liquid carbon dioxide sprayed from the nozzle 1021. Part of the uncondensed carbon dioxide gas in the flash gas is condensed and falls into the bottom of the tower; the flash gas continues to rise and enters the upper part of the distillation purification tower 101 The tube side of the heat exchanger 1012 exchanges heat with the gas mixture that enters the shell side of the heat exchanger 1012 after being throttled by the regulating valve 1013 and the expansion temperature is lowered. Part of the uncondensed carbon dioxide gas in the flash gas is condensed and falls into the tower kettle. The flash gas leaves the tube side of the heat exchanger 1012 and becomes a gas mixture containing a small amount of uncondensed carbon dioxide gas and a large amount of methane and ethylene, and is discharged from the top of the distillation purification tower 101 in the distillation purification process 100 . Part of the carbon dioxide gas from the purification process 80 that has been purified at a temperature of 28-32°C and contains traces of impurities such as methane, ethylene, and oxygen enters the distillation purification tower 101 of the distillation purification process 100 through an orifice flowmeter 1015. It is usually called The inlet of the reboiler 1011 of the kettle coil fully provides the heat source required for the distillation and purification of the product liquid carbon dioxide, and it is discharged from the outlet of the reboiler 1011, which is usually called the tower kettle coil, and the discharge temperature is -9～-11°C , and the other part of carbon dioxide gas containing traces of methane, ethylene, oxygen and other impurities at a temperature of 28-32 °C after purification from the purification process 80, in this other part, the control valve 1016 controlled by the orifice flowmeter 1015 After flowing out, the two parts merge together and enter the first evaporative condenser 91 of the liquefaction process 90 for liquefaction.

(6) supercooling process 110

The product liquid carbon dioxide through distillation purification in the distillation purification tower 101 tower kettle of distillation purification process 100 is sent to the second evaporative condenser 111 of subcooling process 110, and the cold source of the second evaporative condenser 111 of supercooling process 110 is For liquid ammonia, in the second evaporative condenser 111, the temperature of the product liquid carbon dioxide is further reduced, and the product liquid carbon dioxide whose temperature is further lowered is sent to the product liquid carbon dioxide storage tank 112 for storage through a program-controlled valve.

Referring to Fig. 2, the second embodiment of the production method of the food-grade liquid carbon dioxide product that reclaims regeneration gas of the present invention, comprises the following steps:

(1) The first compression process 300

The carbon dioxide raw material gas containing mechanical water, methane, ethylene, benzene and other impurities with a carbon dioxide content of about 99.2% from outside the boundary area is washed with water, and the chemical reaction that is mediated by the regulating valve 2 controlled by the orifice flowmeter 1 is slightly adjusted. The excess oxygen is mixed with the gas flow returned from the purification process 80 to heat the adsorbent, the impurities adsorbed by the adsorbent are heated and desorbed, and the adsorbent is fully regenerated, or the gas flow returned from the purification process 80 to cool the adsorbent Enter the pre-cooler 10 for pre-cooling, go through the first water separator 20 to remove the mechanical water, then enter the first compression process 300, and the pressure is raised to 0.1-0.35Mpa by the first-stage compressor 31 and the pressure is raised to 0.8-0.8-0.8Mpa by the second-stage compressor 32 1.2 MPa, the temperature of the carbon dioxide gas containing methane, ethylene, benzene and other impurities and oxygen from the secondary compressor 32 is 125-135°C, and then sent to the dehydrogenation process 50.

(2) Dehydrogenation process 50

The carbon dioxide gas and oxygen containing methane, ethylene, benzene and other impurities from the first compression process 300 first enter the dehydrogenation preheater 51 to preheat to 215-225°C, and then pass through the dehydrogenation heater 52 to heat to 480-520°C. Finally, it enters the dehydrogenation reactor 53. In the dehydrogenation reactor 53, methane, ethylene and oxygen in the carbon dioxide gas containing impurities such as methane, ethylene and benzene undergo a chemical reaction under the action of a catalyst whose active components are platinum and palladium and whose carrier is alumina under high temperature and pressure. This produces carbon dioxide and water. When the dehydrocarbon preheater 51 is a shell and tube heat exchanger, the high-temperature gas from the dehydrocarbon reactor 53 returns to the shell side of the dehydrocarbon preheater 51, and the methane-containing gas from the first compression process 300 in the tube side , ethylene, benzene and other impurities of carbon dioxide gas heat exchange, first through the heat exchanger 130 and the following confluent air flow for heat exchange, and then through the water cooler 60 to cool down and the second water separator 70 to separate the mechanical water, enter the purification process 80. Through the dehydrogenation process 50, most of the methane and ethylene in the carbon dioxide gas containing impurities such as methane, ethylene, and benzene from the first compression process 300 are converted into carbon dioxide and water, so the carbon dioxide gas entering the purification process 80 contains The trace amount of methane and ethylene that have not been completely removed, as well as the trace amount of oxygen and newly generated water vapor that cannot be separated by the second water separator 70. The dehydrocarbon heater 52 may be an electric heater. The dehydrogenation reactor 53 may have the structure of a general catalytic reactor.

(3) Purification process 80

Using the temperature swing adsorption process, multiple purifiers switch to work. When one or several purifiers 81 are in the adsorption state, the other or several purifiers 82 are in the regeneration state, and the remaining one or several purifiers 83 Then it is in a standby state, absorbing impurities at normal temperature and desorbing impurities at high temperature. The alumina and silica gel adsorbents packed in the purifier are used to treat impurities such as trace methane, ethylene, oxygen, benzene and water vapor from the second water separator 70. The trace water vapor (PPM grade) and trace benzene (PPB grade) impurities in the carbon dioxide gas are selectively adsorbed, and the carbon dioxide gas containing trace methane, ethylene, oxygen, benzene and water vapor and other impurities from the second water separator 70 is selectively adsorbed. Purify.

① Adsorption

The carbon dioxide gas containing impurities such as trace methane, ethylene, oxygen, benzene and water vapor from the second water separator 70 enters the adsorption tower from the bottom of the purifier 81, which is usually called an adsorption tower, and is discharged from the top of the adsorption tower. In the process, the adsorbent effectively adsorbs traces of water vapor and traces of benzene, so that the indicators of water and benzene in the gas at the outlet of the adsorption tower reach the corresponding design indicators or specified standards, and then sent to the second compression process 150, the adsorbent is adsorbed to After a certain time, it is expected that the adsorption will stop when the adsorbent is close to saturation.

②Reverse pressure release

After the adsorption step is completed, the carbon dioxide gas containing trace methane, ethylene, oxygen and other impurities in the adsorption tower is discharged out of the purifier 81 by flow restriction and pressure relief against the adsorption direction. After the end, the pressure in the adsorption tower is close to normal pressure.

③Heating and desorption of impurities

The gas mixture containing a small amount of uncondensed carbon dioxide gas and a large amount of methane, ethylene, and oxygen discharged from the top of the distillation purification tower 101 in the distillation purification process 100, after being throttled and expanded by the regulating valve 1013, the temperature decreases, and enters the heat exchange at the top of the distillation purification tower 101 The shell side of the heat exchanger 1012 exchanges heat with the flash steam rising in the tube side of the heat exchanger 1012. Part of the uncondensed carbon dioxide gas in the flash steam is condensed and falls into the bottom of the distillation purification tower 101, and the rest becomes the above-mentioned gas mixture Discharged from the top of the distillation and purification tower 101, the gas mixture is throttled and expanded by the regulating valve 1013, and the temperature decreases, and enters the shell side of the heat exchanger 1012 on the upper part of the distillation and purification tower 101, and the gas mixture coming out of the shell side of the heat exchanger 1012 passes through the regulating valve After throttling and expansion at 1014, the pressure is lowered to 0.05MPa again, and part of the confluent airflow formed after being merged with the flash gas discharged from the spherical tank 112 enters the heat exchanger 130, and is combined with the dehydrocarbon preheater 51 from the dehydrocarbon process 50 The carbon dioxide gas containing trace impurities such as methane, ethylene, oxygen, benzene, and water vapor enters the electric heater 140 after heat exchange and is heated to 180-235°C, and then enters the purifier 81, which is the adsorption tower, which is in the process of heating and desorbing impurities. Inside, the adsorbent is washed against the direction of adsorption, so that the impurities adsorbed by the adsorbent are heated and desorbed, and the adsorbent is fully regenerated, and then the carbon dioxide containing impurities such as mechanical water, methane, ethylene, and benzene from outside the boundary area is returned. The content of carbon dioxide is about 99.2% of the carbon dioxide in the raw gas.

④Cooling adsorbent

After the step of heating and desorbing impurities is completed, the impurities such as water and benzene adsorbed by the adsorbent in the purifier 81 are almost completely desorbed. At this time, another part of the combined air flow is directly sent to the purifier 81, and the adsorbent in the purifier 81 Cool down to ≤25°C, and then return to the carbon dioxide raw material gas containing mechanical water, methane, ethylene, benzene and other impurities with a carbon dioxide content of about 99.2%.

⑤Purifier charging

Purifier 81 is pressurized to an adsorption pressure of 0.8 to 0.8 by using carbon dioxide gas containing traces of impurities such as methane, ethylene and oxygen from a part of the purifier 82, which has been switched from a regeneration state to an adsorption state, and is generally called an adsorption tower. 1.2MPa, ready to enter the next adsorption.

(4) The second compression process 150

The purified carbon dioxide gas containing traces of methane, ethylene, oxygen and other impurities from the purification process 80 enters the second compression process 150, and is boosted to 2.3-2.8MPa by the compressor 151, and the temperature after cooling is 28-32°C , sent to the liquefaction process 90 and the distillation purification process 100.

(5) Liquefaction process 90

From the second compression process 150, the temperature is 28-32°C and the distillation purification process 100 is at -9--11°C. Part of the carbon dioxide gas containing traces of impurities such as methane, ethylene and oxygen enters the distillation purification process through the orifice flowmeter 1015 The inlet of the reboiler 1011 of the distillation purification column 101, which is usually called the bottom coil, fully provides the heat source required for the distillation and purification of the product liquid carbon dioxide, and is discharged from the outlet of the reboiler 1011, which is usually called the bottom coil. , and the temperature from the second compression process 150 is another part of the carbon dioxide gas containing traces of impurities such as methane, ethylene and oxygen at a temperature of 28-32 ° C. After the other part flows out from the regulating valve 1016 controlled by the orifice flowmeter 1015 , The two parts are merged together and enter the first evaporative condenser 91 of the liquefaction process 90 for liquefaction. The cold source of the first evaporative condenser 91 in the liquefaction process 90 is liquid ammonia. In the first evaporative condenser 91, the carbon dioxide gas containing traces of methane, ethylene, oxygen and other impurities fully exchanges heat with the liquid ammonia, and the first evaporative condensation The liquid ammonia liquid level in the tank 91 is precisely controlled by a regulating valve, so that most of the carbon dioxide gas is fully liquefied to become liquid carbon dioxide at -23--24°C, and then sent to the distillation purification process 100 .

(6) distillation purification process 100

From the first evaporative condenser 91 of the liquefaction process 90, the liquefied carbon dioxide containing uncondensed carbon dioxide gas and traces of impurities such as methane, ethylene, and oxygen enters the tower of the distillation purification tower 101 of the distillation purification process 100 through spray nozzle 1021 mist spray Distillation and purification are carried out in the still, and impurities such as methane, ethylene and oxygen and uncondensed carbon dioxide gas are distilled from the liquefied carbon dioxide, which is called flash gas, and the product liquid carbon dioxide with a temperature of -21 ~ -23°C is obtained in the lower part of the tower kettle. The flash gas rises from the tower kettle and contacts with the mist liquid carbon dioxide sprayed from the nozzle 1021. Part of the uncondensed carbon dioxide gas in the flash gas is condensed and falls into the tower kettle; the flash gas continues to rise and enters the upper part of the distillation purification tower 101 The tube side of the heat exchanger 1012 exchanges heat with the gas mixture that enters the shell side of the heat exchanger 1012 after being throttled by the regulating valve 1013 and the expansion temperature is lowered. Part of the uncondensed carbon dioxide gas in the flash gas is condensed and falls into the tower kettle. The flash gas leaves the tube side of the heat exchanger 1012 and becomes a gas mixture containing a small amount of uncondensed carbon dioxide gas and a large amount of methane and ethylene, and is discharged from the top of the distillation purification tower 101 in the distillation purification process 100 . A part of the carbon dioxide gas from the second compression process 150 with a temperature of 28-32°C containing traces of methane, ethylene, oxygen and other impurities enters the distillation purification column 101 of the distillation purification process 100 through the orifice flowmeter 1015, which is usually called a column tray. The inlet of the reboiler 1011 of the tube fully provides the heat source required for the distillation and purification of the product liquid carbon dioxide, and it is discharged from the outlet of the reboiler 1011, which is usually called a column coil. The temperature of the second compression process 150 is another part of the carbon dioxide gas containing traces of methane, ethylene, oxygen and other impurities at 28-32 °C. After the other part flows out from the regulating valve 1016 controlled by the orifice flowmeter 1015, the two parts Together, they enter the first evaporative condenser 91 of the liquefaction process 90 for liquefaction.

(7) supercooling process 110

The product liquid carbon dioxide through distillation purification in the distillation purification tower 101 tower kettle of distillation purification process 100 is sent to the second evaporative condenser 111 of subcooling process 110, and the cold source of the second evaporative condenser 111 of supercooling process 110 is For liquid ammonia, in the second evaporative condenser 111, the temperature of the product liquid carbon dioxide is further reduced, and the product liquid carbon dioxide whose temperature is further lowered is sent to the product liquid carbon dioxide storage tank 112 for storage through a program-controlled valve.

According to the embodiments of the present invention, the present invention has been described as illustrative rather than restrictive, but it should be understood that those skilled in the art can make changes and modifications without departing from the relevant protection scope defined by the claims. / or modify.

Claims (6)

1. the production method of the food level liquid carbon dioxide product of a reclaiming gas, comprise the following steps:

(1) compression section

CO 2 raw material gas body and the excessive a little oxygen mix of chemical reaction that will contain impurity, with return from cleaning procedure be used for the heating adsorption agent, make adsorbent impurity be heated desorb, adsorbent obtains the air-flow of fully regeneration or enter compression section after the air-flow that is used for cooling adsorbent that cleaning procedure returns is removed mechanical water through separator together, through a stage compressor boost to 0.1～0.35Mpa, split-compressor boosts to 0.8～1.2MPa and three-stage blower 33 boosts to 2.3～2.8MPa, then deliver to and take off the hydrocarbon operation;

(2) take off the hydrocarbon operation

Enter from the carbon dioxide that contains impurity of compression section and the excessive a little oxygen of chemical reaction and take off the hydrocarbon operation, the excessive a little oxygen of methane in taking off hydrocarbon reactor in impurity and ethene and chemical reaction is that 480～520 ℃, pressure are that 2.3～2.8MPa, active component are that platinum and palladium and carrier are that the effect of the catalyst of aluminium oxide issues biochemical reaction in temperature, generate carbon dioxide and water, remove methane and ethene in the carbon dioxide that contains impurity, then deliver to cleaning procedure;

(3) cleaning procedure

adopt temperature swing adsorption process, many clarifier switch operatings, when a certain or several clarifiers are in adsorbed state, another or several clarifiers are in reproduced state, normal temperature absorption impurity, high temperature desorption impurity, by being seated in aluminium oxide in clarifier and silica gel absorber to coming the trace methane that contains of autospasy hydrocarbon operation, ethene, oxygen, PPM level steam in the carbon dioxide of benzene and steam impurity and the selective absorption of PPB level benzene impurity, to coming the trace methane that contains of autospasy hydrocarbon operation, ethene, oxygen, the carbon dioxide of benzene and steam impurity purifies, then deliver to liquefaction operation and distilation operation,

Adding in thermal desorption impurity step therein, will make adsorbent impurity be heated desorb for the heating adsorption agent, and the air-flow that adsorbent obtains fully regeneration returns in the CO 2 raw material gas body that contains impurity;

In cooling adsorbent step therein, will return to for the air-flow of cooling adsorbent the CO 2 raw material gas body that contains impurity;

(4) liquefaction operation

enter the entrance of the reboiler that is commonly referred to the tower reactor coil pipe of the distilation tower of distilation operation through orifice flowmeter from the part of the carbon dioxide that contains impurity of cleaning procedure, fully provide product liquid carbon dioxide distilation required thermal source, discharge from the outlet of this reboiler, with the another part from the carbon dioxide that contains impurity of cleaning procedure, after this another part flows out from the control valve that is subjected to this orifice flowmeter control, these two parts merge together, the evaporative condenser that enters the liquefaction operation liquefies, the carbon dioxide that major part contains impurity is liquefied, then with the methane of uncooled carbon dioxide with trace, ethene and oxygen are delivered to the distilation operation together,

(5) distilation operation

The distilation tower tower reactor that enters the distilation operation from the carbon dioxide after the liquefaction that contains uncooled carbon dioxide and trace methane, ethene and oxygen of liquefaction operation is carried out distilation, methane, ethene and oxygen impurities and uncooled carbon dioxide distill from the carbon dioxide after liquefaction, be called flashed vapour, obtain the product liquid carbon dioxide in the tower reactor bottom.

2. according to the production method of the food level liquid carbon dioxide product of reclaiming gas claimed in claim 1, it is characterized in that: from the carbon dioxide that contains impurity of compression section and excessive a little oxygen at first enter take off the hydrocarbon operation take off the hydrocarbon preheater, then through taking off the hydrocarbon heater, enter at last and take off hydrocarbon reactor.

3. according to the production method of the food level liquid carbon dioxide product of reclaiming gas claimed in claim 2, it is characterized in that: taking off the hydrocarbon preheater is tubular heat exchanger, at first the carbon dioxide that contains impurity and excessive a little oxygen from compression section enter the tube side that takes off the hydrocarbon preheater that takes off the hydrocarbon operation, return to from taking off hydrocarbon reactor high-temperature gas out the shell side that takes off the hydrocarbon preheater.

4. the production method of the food level liquid carbon dioxide product of a reclaiming gas, comprise the following steps:

(1) first compression section

CO 2 raw material gas body and the excessive a little oxygen mix of chemical reaction that will contain impurity, with return from cleaning procedure be used for the heating adsorption agent, make adsorbent impurity be heated desorb, adsorbent obtains the air-flow of fully regeneration or enter compression section after the air-flow that is used for cooling adsorbent that cleaning procedure returns is removed mechanical water through separator together, boost to 0.1～0.35Mpa and split-compressor boosts to 0.8～1.2MPa through a stage compressor, then deliver to and take off the hydrocarbon operation;

(2) take off the hydrocarbon operation

Enter from the carbon dioxide that contains impurity of the first compression section and the excessive a little oxygen of chemical reaction and take off the hydrocarbon operation, the excessive a little oxygen of methane in taking off hydrocarbon reactor in impurity and ethene and chemical reaction is that 480～520 ℃, pressure are that 0.8～1.2MPa, active component are that platinum and palladium and carrier are that the effect of the catalyst of aluminium oxide issues biochemical reaction in temperature, generate carbon dioxide and water, remove methane and ethene in the carbon dioxide that contains impurity, then deliver to cleaning procedure;

(3) cleaning procedure

adopt temperature swing adsorption process, many clarifier switch operatings, when a certain or several clarifiers are in adsorbed state, another or several clarifiers are in reproduced state, normal temperature absorption impurity, high temperature desorption impurity, by being seated in aluminium oxide in clarifier and silica gel absorber to coming the trace methane that contains of autospasy hydrocarbon operation, ethene, oxygen, PPM level steam in the carbon dioxide of benzene and steam impurity and the selective absorption of PPB level benzene impurity, to coming the trace methane that contains of autospasy hydrocarbon operation, ethene, oxygen, the carbon dioxide of benzene and steam impurity purifies, then deliver to the second compression section,

Adding in thermal desorption impurity step therein, will make adsorbent impurity be heated desorb for the heating adsorption agent, and the air-flow that adsorbent obtains fully regeneration returns in the CO 2 raw material gas body that contains impurity;

In cooling adsorbent step therein, will return to for the air-flow of cooling adsorbent the CO 2 raw material gas body that contains impurity;

(4) second compression sections

The carbon dioxide that contains impurity from cleaning procedure enters the second compression section, boosts to 2.3-2.8MPa through the compressor of the second compression section, then delivers to liquefaction operation and distilation operation;

(5) liquefaction operation

enter the entrance of the reboiler that is commonly referred to the tower reactor coil pipe of the distilation tower of distilation operation through orifice flowmeter from the part of the carbon dioxide that contains impurity of the second compression section, fully provide product liquid carbon dioxide distilation required thermal source, discharge from the outlet of this reboiler, with the another part from the carbon dioxide that contains impurity of the second compression section, after this another part flows out from the control valve that is subjected to this orifice flowmeter control, these two parts merge together, the evaporative condenser that enters the liquefaction operation liquefies, the carbon dioxide that major part contains impurity is liquefied, then with the methane of uncooled carbon dioxide with trace, ethene and oxygen are delivered to the distilation operation together,

(6) distilation operation

The distilation tower tower reactor that enters the distilation operation from the carbon dioxide after the liquefaction that contains uncooled carbon dioxide and trace methane, ethene and oxygen of liquefaction operation is carried out distilation, methane, ethene and oxygen impurities and uncooled carbon dioxide distill from the carbon dioxide after liquefaction, be called flashed vapour, obtain the product liquid carbon dioxide in the tower reactor bottom.

5. according to the production method of the food level liquid carbon dioxide product of reclaiming gas claimed in claim 4, it is characterized in that: from the carbon dioxide that contains impurity of the first compression section and excessive a little oxygen at first enter take off the hydrocarbon operation take off the hydrocarbon preheater, then through taking off the hydrocarbon heater, enter at last and take off hydrocarbon reactor.

6. according to the production method of the food level liquid carbon dioxide product of reclaiming gas claimed in claim 5, it is characterized in that: taking off the hydrocarbon preheater is tubular heat exchanger, at first the carbon dioxide that contains impurity and excessive a little oxygen from the first compression section enter the tube side that takes off the hydrocarbon preheater that takes off the hydrocarbon operation, return to from taking off hydrocarbon reactor high-temperature gas out the shell side that takes off the hydrocarbon preheater.

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