Benzene steam recovery system

Abstract

The utility model belongs to the technical field of environmental protection, and relates to a benzene steam recovery system, which comprises a buffer tank, a compressor, a precooler, a condenser, a membrane separator, a liquid collection tank, an adsorption tower I and an adsorption tower II, the precooler is respectively communicated with the condenser and the membrane separator through pipelines, liquid precooled by the precooler enters the liquid collecting tank through the condenser, gas precooled by the precooler enters the membrane separator, benzene steam separated by the membrane separator enters the buffer tank through the vacuum pump, and the gas enters the liquid collecting tank through the vacuum pump. Benzene steam which is not separated by the membrane separator respectively enters the adsorption tower I and the adsorption tower II through pipelines, and the benzene steam which is respectively adsorbed and desorbed by the adsorption tower I and the adsorption tower II enters the buffer tank through the vacuum pump. The membrane separator and the adsorption tower are used for recycling leaked benzene steam, so that the harm of benzene steam leakage to the environment and human health can be effectively reduced.

Description

Technical Field

[0001] This utility model relates to a benzene vapor recovery system, belonging to the field of environmental protection technology. Background Technology

[0002] Volatile organic compounds (VOCs) mainly include aliphatic hydrocarbons and various aromatic alkanes, alkenes, oxygenated hydrocarbons, halogenated hydrocarbons, aldehydes, ketones, etc. VOCs are highly irritating and toxic, possessing carcinogenic, mutagenic, and teratogenic effects. They can also form photochemical smog, damaging the ozone layer. As one of the leading factors of PM2.5, VOCs easily trigger smog, posing a significant threat to human health and the ecological environment. Therefore, the control and treatment of VOCs is urgently needed.

[0003] Benzene-based VOCs, as a class of VOCs, pose undeniable harm to people's lives and health, making VOCs treatment a critical and urgent problem to be solved. During the production of benzene products, benzene vapors endanger the health of workers. Currently, absorption towers are used to absorb and recover benzene vapors, but the recovery rate is low, and the energy consumption for absorbent regeneration is high. Utility Model Content

[0004] The purpose of this invention is to provide a benzene vapor recovery system to solve the technical problems existing in the prior art as described above.

[0005] The technical solution provided by this utility model is as follows: A benzene vapor recovery system includes a buffer tank, a compressor, a precooler, a condenser, a membrane separator, a collection tank, an adsorption tower I, and an adsorption tower II. The buffer tank is connected to the compressor via a pipeline, the compressor is connected to the precooler via a pipeline, and the precooler is connected to the condenser and the membrane separator via pipelines. The liquid precooled by the precooler enters the collection tank through the condenser, and the gas precooled by the precooler enters the membrane separator. The benzene vapor separated by the membrane separator enters the buffer tank through a vacuum pump. The benzene vapor not separated by the membrane separator enters the adsorption tower I and the adsorption tower II through pipelines. The benzene vapor after adsorption and desorption by the adsorption tower I and the adsorption tower II enters the buffer tank through a vacuum pump.

[0006] Based on the above technical solution, the present invention can be further improved as follows:

[0007] Furthermore, the bottom of the adsorption tower I and adsorption tower II are provided with tail gas outlets, and the bottom of the liquid collection tank is provided with a drain outlet.

[0008] Furthermore, the membrane used in the membrane separator is a pervaporation membrane.

[0009] Furthermore, the pervaporation membrane is a polydimethylsiloxane pervaporation membrane or a polymethylphenylsiloxane pervaporation membrane.

[0010] Furthermore, the adsorbents in adsorption tower I and adsorption tower II are porous materials.

[0011] Furthermore, the porous material is activated carbon, 3A molecular sieve, or 5A molecular sieve.

[0012] Furthermore, the permeate-side pressure in the membrane separator is -85 to -98 kPa.

[0013] Furthermore, the adsorption tower I and adsorption tower II employ a pressure swing adsorption-desorption method.

[0014] Furthermore, the adsorption pressure of the pressure swing adsorption-desorption is 200 to 400 kPa, and the desorption pressure is -35 to -85 kPa.

[0015] The technical solution provided by this utility model has the following advantages compared with the prior art:

[0016] The membrane separator of this invention uses a pervaporation membrane, which is simple to operate, has low energy consumption, and high recovery rate;

[0017] This invention uses a membrane separator and an adsorption tower to recover and treat leaked benzene vapor, which can effectively reduce the harm caused by benzene vapor leakage to the environment and human health.

[0018] This invention combines membrane separation with an adsorption tower, which can maximize the recovery of benzene vapor, with good results and low cost, and has great application prospects in the field of organic matter recovery. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] In the diagram, 2 is the buffer tank; 3 is the compressor; 4 is the precooler; 5 is the condenser; 6 is the liquid collection tank; 7 is the drain outlet; 8 is the membrane separator; 9 is the adsorption tower I; 10 is the adsorption tower II; 11 is the vacuum pump; and 13 is the tail gas outlet. Detailed Implementation

[0021] The principles and features of this utility model are described below with reference to examples. The examples are only used to explain this utility model and are not intended to limit the scope of this utility model.

[0022] Example 1:

[0023] like Figure 1As shown, a benzene vapor recovery system includes a buffer tank 2, a compressor 3, a precooler 4, a condenser 5, a membrane separator 8, a collection tank 6, an adsorption tower I 9, and an adsorption tower II 10. The buffer tank 2 is connected to the compressor 3 via a pipeline, and the compressor 3 is connected to the precooler 4 via a pipeline. The precooler 4 is connected to the condenser 5 and the membrane separator 8 via pipelines. The liquid precooled by the precooler 4 enters the collection tank 6 through the condenser 5, and the gas precooled by the precooler 4 enters the membrane separator 8. The benzene vapor separated by the membrane separator 8 enters the buffer tank 2 through a vacuum pump 11. The benzene vapor not separated by the membrane separator 8 enters the adsorption tower I 9 and the adsorption tower II 10 through pipelines. The benzene vapor after adsorption-desorption by the adsorption tower I 9 and the adsorption tower II 10 enters the buffer tank 2 through the vacuum pump 11. The bottom of the adsorption tower I 9 and the adsorption tower II 10 are provided with tail gas outlets 13, and the bottom of the collection tank 6 is provided with a drain outlet 7.

[0024] When the benzene vapor recovery system of this utility model recovers benzene vapor, firstly, the waste gas containing benzene vapor enters the buffer tank 2, then enters the compressor 3, and after compression, it enters the precooler 4. The liquid precooled by the precooler 4 enters the condenser 5, and after further condensation, it enters the collection tank 6 and is discharged through the drain port 7 of the collection tank 6. The gas precooled by the precooler 4 enters the membrane separator 8 for membrane separation. The separated benzene vapor enters the buffer tank 2 through the vacuum pump 11. The unseparated benzene vapor enters the adsorption tower I 9 and adsorption tower II 10 respectively for adsorption-desorption. The obtained benzene vapor enters the buffer tank 2 through the vacuum pump 11. The waste gas separated from benzene vapor is discharged through the tail gas outlet 13.

[0025] The concentration of benzene vapor in the exhaust gas entering buffer tank 2 is 1.78 mg / m³. 3 Membrane separator 8 uses a polydimethylsiloxane pervaporation membrane with a permeate side pressure of -90 kPa. Adsorption towers I (9) and II (10) use activated carbon adsorbents and employ pressure swing adsorption-desorption (PSA) operations, with an adsorption pressure of 300 kPa and a desorption pressure of -50 kPa. The final exhaust gas discharged through tail gas outlet 13 has a benzene vapor concentration of 0.12 mg / m³. 3 .

[0026] Example 2:

[0027] Referring to Example 1, the concentration of benzene vapor in the exhaust gas entering buffer tank 2 is 1.78 mg / m³. 3 Membrane separator 8 uses a polymethylphenylsiloxane pervaporation membrane with a permeate side pressure of -90 kPa. Adsorption towers I (9) and II (10) use activated carbon adsorbents and employ pressure swing adsorption-desorption (PSA) operations, with an adsorption pressure of 300 kPa and a desorption pressure of -50 kPa. The final benzene vapor concentration in the exhaust gas discharged through tail gas outlet 13 is 0.26 mg / m³.3 .

[0028] Example 3:

[0029] Referring to Example 1, the concentration of benzene vapor in the exhaust gas entering buffer tank 2 is 1.78 mg / m³. 3 Membrane separator 8 uses a polydimethylsiloxane pervaporation membrane with a permeate side pressure of -90 kPa. Adsorption towers I 9 and II 10 use 3A molecular sieve adsorbents and employ pressure swing adsorption-desorption operation with an adsorption pressure of 300 kPa and a desorption pressure of -50 kPa. Finally, the benzene vapor concentration in the exhaust gas discharged through tail gas outlet 13 is 0.34 mg / m³. 3 .

[0030] Example 4:

[0031] Referring to Example 1, the concentration of benzene vapor in the exhaust gas entering buffer tank 2 is 1.78 mg / m³. 3 Membrane separator 8 uses a polydimethylsiloxane pervaporation membrane with a permeate side pressure of -90 kPa. Adsorption towers I 9 and II 10 use 5A molecular sieve adsorbents and employ pressure swing adsorption-desorption operation with an adsorption pressure of 300 kPa and a desorption pressure of -50 kPa. Finally, the benzene vapor concentration in the exhaust gas discharged through tail gas outlet 13 is 0.41 mg / m³. 3 .

[0032] In Examples 1-4, the concentration of benzene vapor in the exhaust gas discharged after being recovered and treated by the benzene vapor recovery system meets the emission standards.

[0033] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A benzene vapor recovery system, characterized in that, The system includes a buffer tank (2), a compressor (3), a precooler (4), a condenser (5), a membrane separator (8), a collection tank (6), an adsorption tower I (9), and an adsorption tower II (10). The buffer tank (2) is connected to the compressor (3) via a pipeline. The compressor (3) is connected to the precooler (4) via a pipeline. The precooler (4) is connected to the condenser (5) and the membrane separator (8) via pipelines. The liquid precooled by the precooler (4) passes through the condenser (6). 5) The gas enters the collection tank (6) and is pre-cooled by the precooler (4) and then enters the membrane separator (8). The benzene vapor separated by the membrane separator (8) enters the buffer tank (2) through the vacuum pump (11). The benzene vapor that is not separated by the membrane separator (8) enters the adsorption tower I (9) and adsorption tower II (10) through the pipeline respectively. The benzene vapor after adsorption-desorption by the adsorption tower I (9) and adsorption tower II (10) respectively enters the buffer tank (2) through the vacuum pump (11).

2. The benzene vapor recovery system according to claim 1, characterized in that, The bottom of the adsorption tower I (9) and adsorption tower II (10) are provided with tail gas outlets (13), and the bottom of the liquid collection tank (6) is provided with a drain outlet (7).

3. The benzene vapor recovery system according to claim 1, characterized in that, The membrane used in the membrane separator (8) is a pervaporation membrane.

4. The benzene vapor recovery system according to claim 3, characterized in that, The pervaporation membrane is a polydimethylsiloxane pervaporation membrane or a polymethylphenylsiloxane pervaporation membrane.

5. The benzene vapor recovery system according to claim 1, characterized in that, The adsorbents in adsorption tower I (9) and adsorption tower II (10) are porous materials.

6. The benzene vapor recovery system according to claim 5, characterized in that, The porous material is activated carbon, 3A molecular sieve, or 5A molecular sieve.

7. The benzene vapor recovery system according to claim 1, characterized in that, The permeate side pressure in the membrane separator (8) is -85 to -98 kPa.

8. The benzene vapor recovery system according to claim 1, characterized in that, The adsorption tower I (9) and adsorption tower II (10) adopt the pressure swing adsorption-desorption method.

9. The benzene vapor recovery system according to claim 8, characterized in that, The adsorption pressure of the pressure swing adsorption-desorption is 200-400 kPa, and the desorption pressure is -35-85 kPa.

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