Recovery device for mixed gas of PPVE and carbon dioxide

Abstract

The utility model discloses a recovery device for mixed gas of PPVE and carbon dioxide, and belongs to the field of tail gas treatment. The device comprises a pre-cooling heat exchanger, an intercooling heat exchanger and a deep cooling heat exchanger, a hot side inlet of the pre-cooling heat exchanger is connected with a PPVE and carbon dioxide tail gas conveying pipeline, and a hot side outlet of the pre-cooling heat exchanger is connected with a first hot side inlet of the intercooling heat exchanger; a first hot side outlet of the intercooling heat exchanger is connected with a hot side inlet of the cryogenic heat exchanger, a hot side outlet of the cryogenic heat exchanger is connected with a second hot side inlet of the intercooling heat exchanger, and a second hot side outlet of the intercooling heat exchanger is connected with a tail gas emission pipeline; a cold side inlet of the deep cooling heat exchanger is connected with a liquid nitrogen conveying pipeline, a cold side outlet of the deep cooling heat exchanger is connected with a cold side inlet of the pre-cooling heat exchanger, and a cold side outlet of the pre-cooling heat exchanger is connected with a nitrogen discharging pipeline. According to the device, PPVE is condensed into liquid in a liquid nitrogen condensation mode, the purity of the condensate reaches more than 99.5%, the recovery efficiency is high, and the tail gas treatment effect is good.

Description

Technical Field

[0001] The utility model relates to the field of tail gas treatment, in particular to a recovery device for a PPVE and carbon dioxide mixed gas. Background Art

[0002] PPVE is the abbreviation of perfluoro n-propyl vinyl ether, which is a perfluorinated compound. In the production process of some chemical companies, the equipment will discharge a high concentration of PPVE and carbon dioxide mixed gas. If it is discharged directly, it will cause environmental pollution and fail to meet environmental protection standards. Moreover, PPVE is a special chemical with very high value. If it is treated by physical absorption, chemical adsorption or incineration, it will cause secondary emissions of pollutants and additional energy consumption. Utility Model Content

[0003] Based on the above technical problems, the utility model proposes a recovery device for a mixed gas of PPVE and carbon dioxide.

[0004] The technical solution adopted by this utility model is:

[0005] A PPVE and carbon dioxide mixed gas recovery device comprises a heat exchanger group, the heat exchanger group is connected to the PPVE and carbon dioxide tail gas delivery pipeline;

[0006] The heat exchanger group includes a precooling heat exchanger, an intercooling heat exchanger and a deep cooling heat exchanger, the hot side inlet of the precooling heat exchanger is connected to the PPVE and the carbon dioxide tail gas delivery pipeline, and the hot side outlet of the precooling heat exchanger is connected to the first hot side inlet of the intercooling heat exchanger through the first gas delivery pipeline;

[0007] The first hot side outlet of the intercooler heat exchanger is connected to the hot side inlet of the cryogenic heat exchanger through the second gas delivery pipeline, the hot side outlet of the cryogenic heat exchanger is connected to the second hot side inlet of the intercooler heat exchanger through the third gas delivery pipeline, and the second hot side outlet of the intercooler heat exchanger is connected to the exhaust gas discharge pipeline;

[0008] The cold side inlet of the cryogenic heat exchanger is connected to the first liquid nitrogen delivery pipeline, the cold side outlet of the cryogenic heat exchanger is connected to the cold side inlet of the precooling heat exchanger through the second liquid nitrogen delivery pipeline, and the cold side outlet of the precooling heat exchanger is connected to the nitrogen discharge pipeline;

[0009] The precooling heat exchanger, the intermediate cooling heat exchanger and the deep cooling heat exchanger are also connected to the condensate discharge main pipeline.

[0010] Preferably, an induced draft fan, a first flow meter and a first control valve are provided on the PPVE and the carbon dioxide tail gas delivery pipeline.

[0011] Preferably, a temperature sensor and a pressure sensor are provided on the second gas delivery pipeline and the third gas delivery pipeline; a fifth control valve and a second flow meter are provided on the tail gas discharge pipeline; and a sixth control valve is provided on the nitrogen discharge pipeline.

[0012] Preferably, the heat exchanger group is provided in two sets, namely a first heat exchanger group and a second heat exchanger group, and the first heat exchanger group and the second heat exchanger group are arranged in parallel.

[0013] Preferably, the precooling heat exchanger is connected to the first condensate discharge branch pipeline, the intercooling heat exchanger is connected to the second condensate discharge branch pipeline, and the cryogenic heat exchanger is connected to the third condensate discharge branch pipeline;

[0014] A second control valve is provided on the first condensate discharge branch pipeline, a third control valve is provided on the second condensate discharge branch pipeline, and a fourth control valve is provided on the third condensate discharge branch pipeline;

[0015] The first condensate discharge branch pipeline, the second condensate discharge branch pipeline and the third condensate discharge branch pipeline are all connected to the condensate discharge main pipeline.

[0016] Preferably, the condensate discharge main pipeline is connected to the condensate tank.

[0017] The beneficial technical effects of the utility model are:

[0018] The utility model condenses PPVE into liquid by means of liquid nitrogen condensation, and the purity of the condensate reaches more than 99.5%, and can be directly used in the original production process without causing secondary pollution and additional energy consumption.

[0019] According to calculations, the intake PPVE concentration is about 30,000 PPM, and after liquid nitrogen condensation, the PPVE concentration is about 1,000 PPM, with a recovery rate of more than 97%; recovering 1 kg of PPVE consumes about 9 kg of liquid nitrogen.

[0020] Specifically, the tail gas is condensed step by step through the precooling heat exchanger, the intercooling heat exchanger and the cryogenic heat exchanger, and the temperature is reduced to about -50°C to achieve the condensation recovery effect. The liquid nitrogen enters the cryogenic heat exchanger and gasifies into nitrogen, and then enters the precooling heat exchanger for cold recovery; the exhaust gas passes through the precooling heat exchanger, the intercooling heat exchanger and the cryogenic heat exchanger and returns to the intercooling heat exchanger as a cold source for cold recovery. This arrangement allows the coldness of liquid nitrogen to be fully utilized. The recovery efficiency of the tail gas reaches more than 97% after three-stage condensation of liquid nitrogen. The heat exchanger condenses the PPVE in the tail gas into liquid through three-stage step-by-step heat exchange. By controlling the temperature of the cryogenic exhaust at about -50°C, it is ensured that carbon dioxide will not condense into solid due to too low a temperature, thereby causing ice blockage of the heat exchanger, thereby ensuring the stable operation of the heat exchanger.

[0021] The utility model further provides two groups of heat exchangers, which can be specifically divided into two paths, A and B. After path A runs for a period of time and the pressure difference reaches a set value, the equipment switches to path B for operation, and path A performs condensate collection and defrosting. A and B operate alternately to ensure stable operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments:

[0023] Figure 1 The figure is a schematic diagram of the structural principle of an implementation method of the utility model.

[0024] In the figure: 1-PPVE and carbon dioxide tail gas delivery pipeline, 2-precooling heat exchanger, 3-intercooling heat exchanger, 4-cryogenic heat exchanger, 5-first gas delivery pipeline, 6-second gas delivery pipeline, 7-third gas delivery pipeline, 8-tail gas discharge pipeline, 9-first liquid nitrogen delivery pipeline, 10-second liquid nitrogen delivery pipeline, 11-nitrogen discharge pipeline, 12-induced draft fan, 13-first flow meter, 14-first control valve, 15-second control valve, 16-third control valve, 17-fourth control valve, 18-fifth control valve, 19-second flow meter, 20-sixth control valve, 21-condensate discharge main pipeline, 22-first connecting pipeline, 23-seventh control valve, 24-second connecting pipeline, 25-eighth control valve. DETAILED DESCRIPTION

[0025] like Figure 1 As shown, a PPVE and carbon dioxide mixed gas recovery device includes a heat exchanger group, and the heat exchanger group is connected to the PPVE and carbon dioxide tail gas delivery pipeline 1. The heat exchanger group includes a precooling heat exchanger 2, an intercooling heat exchanger 3 and a cryogenic heat exchanger 4. The hot side inlet of the precooling heat exchanger 2 is connected to the PPVE and carbon dioxide tail gas delivery pipeline 1, and the hot side outlet of the precooling heat exchanger 2 is connected to the first hot side inlet of the intercooling heat exchanger 3 through a first gas delivery pipeline 5. The first hot side outlet of the intercooling heat exchanger 3 is connected to the hot side inlet of the cryogenic heat exchanger 4 through a second gas delivery pipeline 6, and the hot side outlet of the cryogenic heat exchanger 4 is connected to the second hot side inlet of the intercooling heat exchanger 3 through a third gas delivery pipeline 7, and the second hot side outlet of the intercooling heat exchanger 3 is connected to the tail gas discharge pipeline 8. The cold side inlet of the cryogenic heat exchanger 4 is connected to the first liquid nitrogen delivery pipeline 9, the cold side outlet of the cryogenic heat exchanger 4 is connected to the cold side inlet of the precooling heat exchanger 2 through the second liquid nitrogen delivery pipeline 10, and the cold side outlet of the precooling heat exchanger 2 is connected to the nitrogen discharge pipeline 11.

[0026] An induced draft fan 12, a first flow meter 13 and a first control valve 14 are provided on the PPVE and carbon dioxide tail gas delivery pipeline 1. A temperature sensor and a pressure sensor are provided on the second gas delivery pipeline 6 and the third gas delivery pipeline 7. A fifth control valve 18 and a second flow meter 19 are provided on the tail gas discharge pipeline 8. A sixth control valve 20 is provided on the nitrogen discharge pipeline 11.

[0027] The precooling heat exchanger 2 is connected to the first condensate discharge branch pipeline, the intercooling heat exchanger 3 is connected to the second condensate discharge branch pipeline, and the cryogenic heat exchanger 4 is connected to the third condensate discharge branch pipeline. A second control valve 15 is provided on the first condensate discharge branch pipeline, a third control valve 16 is provided on the second condensate discharge branch pipeline, and a fourth control valve 17 is provided on the third condensate discharge branch pipeline. The first condensate discharge branch pipeline, the second condensate discharge branch pipeline, and the third condensate discharge branch pipeline are all connected to the condensate discharge main pipeline 21. The condensate discharge main pipeline 21 is connected to the condensate tank.

[0028] The utility model condenses PPVE into liquid by means of liquid nitrogen condensation, and the purity of the condensate reaches more than 99.5%, and can be directly used in the original production process without causing secondary pollution and additional energy consumption.

[0029] Specifically, the tail gas is condensed step by step through the precooling heat exchanger 2, the intercooling heat exchanger 3 and the cryogenic heat exchanger 4, and the temperature is reduced to about -50°C to achieve the condensation recovery effect. The liquid nitrogen enters the cryogenic heat exchanger and gasifies into nitrogen, and then enters the precooling heat exchanger for cold recovery; the exhaust gas passes through the precooling heat exchanger, the intercooling heat exchanger and the cryogenic heat exchanger and returns to the intercooling heat exchanger as a cold source for cold recovery. This arrangement enables the coldness of liquid nitrogen to be fully utilized. The recovery efficiency of the tail gas reaches more than 97% after three-stage condensation of liquid nitrogen. The heat exchanger condenses the PPVE in the tail gas into liquid through three-stage step-by-step heat exchange. By controlling the temperature of the cryogenic exhaust at about -50°C, it is ensured that carbon dioxide will not condense into solid due to too low a temperature, thereby causing ice blockage of the heat exchanger, thereby ensuring the stable operation of the heat exchanger.

[0030] As a further design of the utility model, the heat exchanger group is provided with two sets, namely the first heat exchanger group and the second heat exchanger group, and the first heat exchanger group and the second heat exchanger group are provided in parallel. The first heat exchanger group and the second heat exchanger group are both connected to the first liquid nitrogen delivery pipeline, the nitrogen discharge pipeline, the PPVE and the carbon dioxide tail gas delivery pipeline, the tail gas discharge pipeline and the condensate discharge main pipeline. Accordingly, a first connecting pipeline 22 is provided between the nitrogen discharge pipeline connected to the first heat exchanger group and the first liquid nitrogen delivery pipeline connected to the second heat exchanger group, and a seventh control valve 23 is provided on the first connecting pipeline 22; a second connecting pipeline 24 is provided between the nitrogen discharge pipeline connected to the second heat exchanger group and the first liquid nitrogen delivery pipeline connected to the first heat exchanger group, and an eighth control valve 25 is provided on the second connecting pipeline 24.

[0031] The utility model sets two groups of heat exchangers, which can be operated simultaneously or alternately. If the pressure difference reaches the set value after the first group of heat exchangers has been operated for a period of time, the second group of heat exchangers will be switched to operate, and the first group of heat exchangers will collect condensate and defrost. The first group of heat exchangers and the second group of heat exchangers are operated alternately to ensure the stable operation of the device.

[0032] The working process of the utility model is roughly as follows:

[0033] The PPVE and carbon dioxide mixed waste gas discharged from the factory is transported to the precooling heat exchanger 2 through the carbon dioxide tail gas delivery pipeline 1 for precooling. The precooled waste gas is transported to the intercooling heat exchanger 3 through the first gas delivery pipeline 5 for further cooling. The cooled waste gas is then transported to the deep cooling heat exchanger 4 through the second gas delivery pipeline 6 for deep condensation, so that the waste gas is condensed step by step. The condensed liquid condensed in the precooling heat exchanger 2, the intercooling heat exchanger 3 and the deep cooling heat exchanger 4 can be discharged through the condensate discharge branch pipelines respectively, and finally collected to the condensate tank through the condensate discharge main pipeline 21.

[0034] The gas discharged from the cryogenic heat exchanger 4 is returned to the intercooling heat exchanger 3 through the third gas delivery pipeline 7 for cold recycling and further condensation, and then discharged to the outside through the tail gas discharge pipeline 8.

[0035] The liquid nitrogen is first transported to the cryogenic heat exchanger 4 through the first liquid nitrogen transport pipeline 9, then passes through the intermediate cooling heat exchanger 3, and is directly transported to the precooling heat exchanger 2 through the second liquid nitrogen transport pipeline 10, and is discharged through the nitrogen discharge pipeline 11 after precooling.

[0036] This arrangement allows the coldness of liquid nitrogen to be fully utilized. The recovery efficiency of the tail gas after three-stage condensation of liquid nitrogen reaches more than 97%. The heat exchanger condenses the PPVE in the tail gas into liquid through three-stage step-by-step heat exchange. By controlling the temperature of the deep-cold exhaust gas at around -50°C, it ensures that carbon dioxide will not condense into solid due to too low a temperature, thereby causing ice blockage of the heat exchanger, thus ensuring the stable operation of the heat exchanger.

[0037] The parts not mentioned in the above methods can be realized by adopting or drawing on existing technologies.

[0038] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for recovering a mixture of PPVE and carbon dioxide, characterized in that: It includes a heat exchanger group, which is connected to the PPVE and the carbon dioxide tail gas transmission pipeline; The heat exchanger group includes a precooling heat exchanger, an intercooling heat exchanger and a deep cooling heat exchanger, the hot side inlet of the precooling heat exchanger is connected to the PPVE and the carbon dioxide tail gas delivery pipeline, and the hot side outlet of the precooling heat exchanger is connected to the first hot side inlet of the intercooling heat exchanger through the first gas delivery pipeline; The first hot side outlet of the intercooler heat exchanger is connected to the hot side inlet of the cryogenic heat exchanger through the second gas delivery pipeline, the hot side outlet of the cryogenic heat exchanger is connected to the second hot side inlet of the intercooler heat exchanger through the third gas delivery pipeline, and the second hot side outlet of the intercooler heat exchanger is connected to the exhaust gas discharge pipeline; The cold side inlet of the cryogenic heat exchanger is connected to the first liquid nitrogen delivery pipeline, the cold side outlet of the cryogenic heat exchanger is connected to the cold side inlet of the precooling heat exchanger through the second liquid nitrogen delivery pipeline, and the cold side outlet of the precooling heat exchanger is connected to the nitrogen discharge pipeline; The precooling heat exchanger, the intermediate cooling heat exchanger and the deep cooling heat exchanger are also connected to the condensate discharge main pipeline.

2. The device for recovering a mixture of PPVE and carbon dioxide according to claim 1, characterized in that: An induced draft fan, a first flow meter and a first control valve are arranged on the PPVE and carbon dioxide tail gas delivery pipeline.

3. The device for recovering a mixture of PPVE and carbon dioxide according to claim 1, characterized in that: The second gas delivery pipeline and the third gas delivery pipeline are both provided with temperature sensors and pressure sensors; the tail gas discharge pipeline is provided with a fifth control valve and a second flow meter; and the nitrogen discharge pipeline is provided with a sixth control valve.

4. The device for recovering a mixture of PPVE and carbon dioxide according to claim 1, characterized in that: The heat exchanger group is provided with two sets, namely a first heat exchanger group and a second heat exchanger group, and the first heat exchanger group and the second heat exchanger group are provided in parallel.

5. The device for recovering a mixture of PPVE and carbon dioxide according to claim 1, characterized in that: The precooling heat exchanger is connected to the first condensate discharge branch pipeline, the intercooling heat exchanger is connected to the second condensate discharge branch pipeline, and the cryogenic heat exchanger is connected to the third condensate discharge branch pipeline; A second control valve is provided on the first condensate discharge branch pipeline, a third control valve is provided on the second condensate discharge branch pipeline, and a fourth control valve is provided on the third condensate discharge branch pipeline; The first condensate discharge branch pipeline, the second condensate discharge branch pipeline and the third condensate discharge branch pipeline are all connected to the condensate discharge main pipeline.

6. The device for recovering a mixture of PPVE and carbon dioxide according to claim 1, characterized in that: The condensate discharge main pipeline is connected to the condensate tank.

Images