Gas separation system

Abstract

The utility model discloses a gas separation system which comprises a pre-cooling device, the pre-cooling device is used for pre-cooling mixed gas, the pre-cooling device is connected with a condenser along the conveying direction of the mixed gas, the condenser is connected with a gas-liquid separator, and the condenser is used for further subzero treatment of the pre-cooled mixed gas. And the gas is conveyed into a gas-liquid separator to be separated. According to the utility model, the cooling of the mixed gas is divided into two processes of precooling and copious cooling, the precooling is implemented by the precooling device, and the copious cooling is implemented by the condenser, so that the gas separation system can be combined with the actual production of supercritical physical foaming; nitrogen and carbon dioxide mixed gas recycled from the high-pressure reaction kettle is pressurized by fully utilizing a compressor in an original high-pressure reaction kettle recycling system and then is separated, and the separated gas is subjected to energy recovery in a heat exchange manner, so that energy conservation and emission reduction are realized, and a large amount of gas and power utilization cost can be reduced for enterprises; and the emission of carbon dioxide is also reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to gas recycling technical field, concretely relates to a gas separation system. BACKGROUND

[0002] Supercritical physical foaming is a kind of technology using CO2 / N2 as foaming agent, makes it form supercritical fluid state under high temperature and high pressure condition, rapidly diffuses into high molecular matrix, and then completes material foaming by pressure rapid release or temperature rapid promotion.Compared with traditional foaming method, supercritical foaming has higher environmental friendliness, because it does not need to use traditional harmful chemical foaming agent, and CO2 and N2 are stable in chemical property, non-toxic and harmless.

[0003] After each material foaming is completed, high temperature and high pressure mixed gas (nitrogen and carbon dioxide) in high-pressure reaction kettle is generally directly vented, a large amount of gas is wasted, the cost of enterprise is improved, and a large amount of greenhouse gas (carbon dioxide) is discharged to atmosphere, which also has influence on natural environment. UTILITARIAN CONTENT

[0004] The utility model discloses a gas separation system, which is suitable for a high-pressure reaction kettle gas recycling system.

[0005] The utility model discloses a gas separation system, which is suitable for a high-pressure reaction kettle gas recycling system.

[0006] A kind of gas separation system, it is suitable for high-pressure reaction kettle gas recycling and reusing system, the high-pressure reaction kettle gas recycling and reusing system includes high-pressure reaction kettle and compressor, the compressor is connected with precooling device along mixed gas conveying direction, the precooling device is used to carry out precooling treatment to mixed gas, the precooling device is connected with condensing machine along mixed gas conveying direction, the condensing machine connects gas-liquid separator, the condensing machine is used to further deep cooling treatment to the mixed gas after precooling, and it is sent to the gas-liquid separator and is separated, backflow pipeline is arranged between the gas-liquid separator and the precooling device, low-temperature gas separated out of the gas-liquid separator flows into the precooling device as refrigerant and carries out heat exchange by the backflow pipeline.

[0007] As a further scheme of the utility model: the precooling device includes first heat exchanger, the first heat exchanger is sequentially connected precooling device, second heat exchanger, third heat exchanger along mixed gas conveying direction.

[0008] As a further scheme of the utility model: the output end of the third heat exchanger is connected with the input end of the condensing machine and communicates.

[0009] As a further scheme of the utility model: two output ends of the gas-liquid separator are connected with two reflux pipelines respectively, one reflux pipeline is connected with the second heat exchanger for conveying nitrogen, and the other reflux pipeline is connected with the third heat exchanger for conveying carbon dioxide.

[0010] As a further scheme of the utility model: a pressure stabilizing valve is arranged on the reflux pipeline for conveying nitrogen, and a condensate discharge valve is arranged on the reflux pipeline for conveying carbon dioxide.

[0011] As a further scheme of the utility model: the gas-liquid separator is provided with a liquid level transmitter.

[0012] As a further scheme of the utility model: the refrigerant output end of the second heat exchanger is connected with the refrigerant input end of the first heat exchanger through a pipeline.

[0013] As a further scheme of the utility model: the refrigerant output end of the first heat exchanger is connected with the high-pressure reaction kettle through a pipeline.

[0014] As a further scheme of the utility model: the refrigerant output end of the third heat exchanger is connected with a recovery tank through a pipeline.

[0015] As a further scheme of the utility model: the input end of the compressor is connected with a storage tank.

[0016] The utility model has the advantages of:

[0017] In the utility model, the cooling of the mixed gas includes two processes of precooling and deep cooling, the precooling is implemented by a precooling device, and the deep cooling is implemented by a condensing machine, the gas separation system can combine the actual production of supercritical physical foaming, fully utilize the compressor in the original high-pressure reaction kettle gas recovery and reuse system to pressurize the nitrogen and carbon dioxide mixed gas recovered from the high-pressure reaction kettle, separate the mixed gas again, and recover energy through heat exchange, thereby not only saving energy and reducing emissions and reducing the gas and electricity cost of enterprises, but also reducing the emission of carbon dioxide. BRIEF DESCRIPTION OF DRAWINGS

[0018] The utility model will be further described below in combination with the drawings.

[0019] Figure 1 It is the structure schematic view of the gas separation system of the utility model.

[0020] In the drawings:

[0021] 1, high pressure reactor; 2, storage tank; 3, pre-cooling device; 31, first heat exchanger; 32, pre-cooler; 33, second heat exchanger; 34, third heat exchanger; 4, condensing machine; 5, gas-liquid separator; 51, liquid level transmitter; 6, pressure stabilizing valve; 7, condensate discharge valve; 8, recovery tank; 9, compressor. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.

[0023] Please refer to Figure 1 The utility model discloses a kind of gas separation systems, applicable to high pressure reactor gas recovery and reuse system, high pressure reactor gas recovery and reuse system includes high pressure reactor 1 and compressor 9, compressor 9 input end connects storage tank 2. High pressure reactor 1 is recycled after every material foaming is completed, mixed gas (N2 and CO2 are mixed) in storage tank 2 is pressurized after entering gas separation system by compressor 9.

[0024] In the gas separation system, pre-cooling device 3 is connected with compressor 9 along the mixed gas conveying direction, and pre-cooling device 3 is used for pre-cooling treatment of the mixed gas.

[0025] Specifically, pre-cooling device 3 includes first heat exchanger 31, and first heat exchanger 31 is sequentially connected with pre-cooler 32, second heat exchanger 33 and third heat exchanger 34 along the mixed gas conveying direction. Wherein, first heat exchanger 31 and second heat exchanger 33 are N2 / N2 heat exchanger, and third heat exchanger 34 is N2 / CO2 heat exchanger. N2 / N2 heat exchanger and N2 / CO2 heat exchanger are used to cool high-temperature mixed gas by using low-temperature pure gas (N2 or CO2) as refrigerant, which can also be understood as high-temperature mixed gas heating low-temperature pure gas.

[0026] Pre-cooler 32 is an air-cooled cooler with a variable frequency fan, which is mainly used for cooling mixed gas at the initial stage of system startup. The speed of the fan is controlled by PLC according to the gas temperature output by first heat exchanger 31, and the speed of the fan decreases with the decrease of the gas temperature output by first heat exchanger 31. When the gas temperature reaches the preset value, the fan stops working. The pre-cooling of high-temperature mixed gas is completed by first heat exchanger 31, second heat exchanger 33 and third heat exchanger 34.

[0027] Further, the refrigerant output end of the second heat exchanger 33 is connected to the refrigerant input end of the first heat exchanger 31 through a pipeline, so that the refrigerant (N2) in the second heat exchanger 33 can be used twice as refrigerant after cooling the mixed gas and entering the first heat exchanger 31. The refrigerant (N2) output end of the first heat exchanger 31 is connected to the high-pressure reactor 1 through a pipeline, so that the nitrogen gas can be heated to high-temperature nitrogen gas after heat exchange with the mixed gas as refrigerant, and the high-temperature nitrogen gas can be used as a supply gas into the high-pressure reactor 1. The refrigerant output end of the third heat exchanger 34 is connected to the recovery tank 8 through a pipeline, and the refrigerant (CO2) in the third heat exchanger 34 is heated to normal-temperature CO2 after heat exchange with the mixed gas, and the normal-temperature CO2 is stored in the recovery tank 8 for subsequent use as a supply gas into the high-pressure reactor 1.

[0028] The pre-cooling device 3 is connected to the condenser 4 along the mixed gas conveying direction, specifically, the output end of the third heat exchanger 34 is connected to the input end of the condenser 4. The condenser 4 is further connected to the gas-liquid separator 5, and the condenser 4 is used for further deep cooling treatment of the pre-cooled mixed gas and conveying the pre-cooled mixed gas to the gas-liquid separator 5 for separation.

[0029] Further, the gas-liquid separator 5 and the pre-cooling device 3 are provided with a reflux pipeline, and the low-temperature gas separated from the gas-liquid separator 5 flows into the pre-cooling device 3 as refrigerant for heat exchange through the reflux pipeline.

[0030] Specifically, the two output ends of the gas-liquid separator 5 are connected to two reflux pipelines respectively, one reflux pipeline is connected to the second heat exchanger 33 for conveying nitrogen gas, and the other reflux pipeline is connected to the third heat exchanger 34 for conveying carbon dioxide. The reflux pipeline for conveying nitrogen gas is provided with a pressure stabilizing valve 6, and the reflux pipeline for conveying carbon dioxide is provided with a condensate discharge valve 7. The gas-liquid separator 5 is provided with a liquid level transmitter 51, which can control the condensate discharge valve 7, so that the liquid level in the gas-liquid separator 5 can be kept within a set range, and the condensate discharge valve 7 can be opened.

[0031] In the embodiment, the nitrogen and carbon dioxide mixed gas from the tank 2 is pressurized by the compressor 9, and then sequentially enters the first heat exchanger 31, the pre-cooler 32, the second heat exchanger 33 and the third heat exchanger 34 for pre-cooling, and then enters the condenser 4 for deep cooling (deep cooling). The mixed gas at the preset temperature enters the gas-liquid separator 5, and the carbon dioxide and nitrogen are separated. The carbon dioxide is condensed into liquid and deposited in the lower part of the gas-liquid separator 5, and the nitrogen is in the upper part. The low-temperature nitrogen separated by the gas-liquid separator 5 enters the second heat exchanger 33 and the first heat exchanger 31, and exchanges heat with the high-temperature mixed gas from the compressor 9. While cooling the high-temperature mixed gas, the low-temperature nitrogen is heated to high-temperature nitrogen, which is used in the high-pressure reactor 1. The liquid carbon dioxide in the lower part of the gas-liquid separator 5 is discharged through the condensate discharge valve 7, and then gasified into gaseous CO2, which enters the third heat exchanger 34 for heat exchange. While the mixed gas cooled by the second heat exchanger 33 is deeply cooled in the third heat exchanger 34, the low-temperature gaseous CO2 is heated to normal-temperature CO2, which is stored in the recovery tank 8 for subsequent use in the high-pressure reactor 1.

[0032] In order to ensure the purity of the separated nitrogen, the gas pressure in the gas-liquid separator 5 needs to be controlled (controlling the gas pressure is to control the partial pressure of CO2. If the partial pressure of CO2 is greater than the saturated vapor pressure of CO2 at the set temperature, CO2 will be precipitated). That is, the gas pressure in the gas-liquid separator 5 is ensured to be not less than the set value by adjusting the pressure stabilizing valve 6. The gas-liquid separator 5 also needs to be liquid-sealed by setting the liquid level to ensure that no nitrogen enters the recovery tank 8. The condensate discharge valve 7 is controlled by the liquid level transmitter 51 arranged on the gas-liquid separator 5. The condensate discharge valve 7 can be opened only when the liquid level in the gas-liquid separator 5 is within the set range. The saturated vapor pressure of CO2 determines the content of CO2. Therefore, the purity requirement of nitrogen determines the condensation temperature and pressure of CO2, that is, the set value of the gas pressure in the gas-liquid separator 5 and the preset temperature value of the deep cooling of the condenser 4 are determined according to the purity requirement of nitrogen. According to the physical properties of CO2, the higher the gas pressure, the higher the condensation temperature of CO2. In order to reduce the power consumption of the condenser 4, the gas pressure in the gas-liquid separator 5 can be set to the required N2 pressure of the user. The CO2 has a higher partial pressure, and the condensation temperature of CO2 is higher. Therefore, the refrigerating capacity of the condenser 4 can be smaller, which is convenient for saving energy.

[0033] In the present application, the compressor 9 in the original high-pressure reactor gas recovery and reuse system can be combined with the actual production in the field of supercritical physical foaming to pressurize the recovered mixed gas, and then cool, separate and heat the mixed gas. The heating process of the separated pure gas is a heat exchange process with the high-temperature gas discharged from the compressor 9, which is an energy recovery process.

[0034] It needs to be explained that the cooling of the mixed gas is divided into two processes, pre-cooling and deep cooling, the pre-cooling is implemented by the pre-cooling device 3, and the deep cooling is implemented by the condensing machine 4. The pre-cooling device 3 utilizes low-temperature pure gas (N2, CO2) to cool the high-temperature mixed gas, so that the gas separation system is used as an energy recovery system, after running for a period of time, the fan of the pre-cooler 32 does not need to work, and the system can completely utilize the low-temperature pure gas (N2, CO2) separated out after deep cooling by the condensing machine 4 to cool the high-temperature mixed gas. The secondary heat exchange is used as an energy recovery process, which not only reduces the temperature of the mixed gas entering the condensing machine 4, but also simultaneously increases the supply temperature of nitrogen and carbon dioxide. The lower the temperature of the gas entering the condensing machine 4, the smaller the power of the condensing machine 4, and the higher the supply temperature of nitrogen and carbon dioxide, the shorter the heating time of the high-pressure reaction kettle 1 when the material is foamed, and the lower the power consumption, thereby effectively saving the electric energy.

[0035] It can be understood that the gas separation system separates, purifies and reuses the nitrogen and carbon dioxide mixed gas recovered from the high-pressure reaction kettle 1, which not only saves energy and reduces emissions and reduces a large amount of gas and electricity costs for enterprises, but also reduces the emission of carbon dioxide.

[0036] The working principle of the utility model is: the nitrogen and carbon dioxide mixed gas from the storage tank 2 is pressurized by the compressor 9 and then enters the first heat exchanger 31, the pre-cooler 32, the second heat exchanger 33 and the third heat exchanger 34 in sequence for pre-cooling, and then enters the condensing machine 4 for deep cooling (deep cooling), the mixed gas deep-cooled to the preset temperature enters the gas-liquid separator 5, the carbon dioxide is separated from the nitrogen, the carbon dioxide is condensed into liquid and deposited in the lower part of the gas-liquid separator 5, and the nitrogen is in the upper part. The low-temperature nitrogen separated out by the gas-liquid separator 5 enters the second heat exchanger 33 and the first heat exchanger 31 and exchanges heat with the high-temperature mixed gas from the compressor 9, so that the high-temperature mixed gas is cooled and the low-temperature nitrogen is heated to high-temperature nitrogen for use of the high-pressure reaction kettle 1. The liquid carbon dioxide in the lower part of the gas-liquid separator 5 is discharged through the condensate valve 7 and then gasified into gaseous CO2 and enters the third heat exchanger 34 for heat exchange, the mixed gas cooled by the second heat exchanger 33 is deep-cooled in the third heat exchanger 34, the low-temperature gaseous CO2 is heated to normal-temperature CO2 and stored in the recovery tank 8 for use of the subsequent high-pressure reaction kettle 1.

[0037] The above embodiment of the utility model is described in detail, but the content described can only be the preferred embodiment of the utility model, and cannot be considered as limiting the implementation range of the utility model. Any equivalent change and improvement within the scope of the utility model application should still belong to the scope of the claims of the utility model.

Claims

1. A gas separation system suitable for a high-pressure reactor gas recycling system comprising a high-pressure reactor (1) and a compressor (9), characterized in that, The compressor (9) is connected with a pre-cooling device (3) along the mixed gas conveying direction, and the pre-cooling device (3) is used for pre-cooling treatment of the mixed gas. The pre-cooling device (3) is connected with a condensing machine (4) along the mixed gas conveying direction, the condensing machine (4) is connected with a gas-liquid separator (5), and the condensing machine (4) is used for further deep cooling treatment of the pre-cooled mixed gas and conveying the mixed gas to the gas-liquid separator (5) for separation. A reflux pipeline is arranged between the gas-liquid separator (5) and the pre-cooling device (3), and the low-temperature gas separated by the gas-liquid separator (5) flows into the pre-cooling device (3) as a refrigerant for heat exchange.

2. A gas separation system according to claim 1, wherein, The pre-cooling device (3) comprises a first heat exchanger (31), and the first heat exchanger (31) is connected with a pre-cooler (32), a second heat exchanger (33) and a third heat exchanger (34) in sequence along the mixed gas conveying direction.

3. A gas separation system according to claim 2, wherein, The output end of the third heat exchanger (34) is connected with the input end of the condensing machine (4).

4. A gas separation system according to claim 2, wherein, The two output ends of the gas-liquid separator (5) are connected with two reflux pipelines respectively, one of the reflux pipelines is connected with the second heat exchanger (33) for conveying nitrogen, and the other of the reflux pipelines is connected with the third heat exchanger (34) for conveying carbon dioxide.

5. A gas separation system according to claim 4, wherein, A pressure stabilizing valve (6) is arranged on the reflux pipeline for conveying nitrogen, and a condensate discharge valve (7) is arranged on the reflux pipeline for conveying carbon dioxide.

6. The gas separation system of claim 1, wherein, The gas-liquid separator (5) is provided with a liquid level transmitter (51).

7. A gas separation system according to claim 2, wherein The refrigerant output end of the second heat exchanger (33) is connected with the refrigerant input end of the first heat exchanger (31) through a pipeline.

8. A gas separation system according to claim 2, wherein, The refrigerant output end of the first heat exchanger (31) is connected with the high-pressure reaction kettle (1) through a pipeline.

9. The gas separation system of claim 2, wherein, The refrigerant output end of the third heat exchanger (34) is connected with a recovery tank (8) through a pipeline.

10. The gas separation system of claim 1, wherein, The input end of the compressor (9) is connected with a storage tank (2).

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