Chloromethane recovery system

Abstract

The utility model provides a chloromethane recovery system. The chloromethane recovery system comprises a chloromethane tower, a condenser, a gas-liquid separator, a filter, a heater and membrane separation equipment which are communicated in sequence, the condenser comprises a condenser inlet and a condenser outlet, and the chloromethane tower is communicated with the condenser inlet; the gas-liquid separator comprises a gas-liquid separator inlet and a gas-liquid separator outlet, and the condenser outlet is communicated with the gas-liquid separator inlet; the filter comprises a filter inlet and a filter outlet, and the gas-liquid separator outlet is communicated with the filter inlet; the heater comprises a heater inlet and a heater outlet, and the filter outlet is communicated with the heater inlet; the membrane separation equipment comprises a membrane separation equipment inlet and a membrane separation equipment first outlet, the heater outlet is communicated with the membrane separation equipment inlet, and the membrane separation equipment first outlet is communicated with the chloromethane tower. Through the system, the recovery efficiency of chloromethane in the chloromethane recovery system can be effectively improved, the whole process is low in safety risk, and the treatment mode is green and environment-friendly.

Description

Technical Field

[0001] The utility model relates to the field of organic silicon, in particular to a chloromethane recovery system. Background Art

[0002] Methyl chloride, also known as monochloromethane and methyl chloride, is mainly used in the production of methylchlorosilane monomer. Methyl chloride is flammable and explosive, with an explosion limit (volume fraction) of 8.1%-18.2%. It hydrolyzes into methanol and hydrogen chloride at high temperatures (above 400°C). Therefore, once an explosion or large-scale leakage occurs, it will have a serious negative impact on environmental safety. The maximum allowable emission concentration of methyl chloride in the VOCS emission standards formulated by various parts of my country is becoming increasingly stringent. The "Shandong Provincial Local Standard" DB 37 / 2801.6-2018 requires that the single factor emission concentration of methyl chloride be less than 20mg / m 3 It can be seen that recycling methyl chloride can not only improve economic benefits, but also achieve energy conservation and emission reduction.

[0003] The synthetic raw materials of methylchlorosilane monomer include methyl chloride and silicon powder. In the process of synthesizing methylchlorosilane monomer by methyl chloride, methyl chloride is controlled to be excessive. Therefore, there is a recovery system for methyl chloride. In the prior art, methyl chloride is recovered by condensation on a recovery tower. However, due to the low boiling point of methyl chloride (-23.6°C), a part of methyl chloride still remains in the vented air (i.e., non-condensable gas) after condensation and is not recovered (the methyl chloride content in the vented air is about 10%). This will, on the one hand, lead to potential safety hazards to the environment, and on the other hand, also lead to the problems of methyl chloride waste and low methyl chloride recovery efficiency.

[0004] Therefore, how to provide a method for improving the recovery efficiency of methyl chloride in a methyl chloride recovery system is an urgent problem to be solved. Utility Model Content

[0005] In view of the problem of low methyl chloride recovery efficiency in methyl chloride recovery systems in the prior art, the present application provides a methyl chloride recovery system capable of improving the methyl chloride recovery efficiency.

[0006] According to one aspect of the present application, a chloromethane recovery system is provided, comprising a chloromethane tower, a condenser, a gas-liquid separator, a filter, a heater and a membrane separation device connected in sequence; wherein: the condenser comprises a condenser inlet and a condenser outlet, and the chloromethane tower is connected to the condenser inlet; the gas-liquid separator comprises a gas-liquid separator inlet and a gas-liquid separator outlet, and the condenser outlet is connected to the gas-liquid separator inlet; the filter comprises a filter inlet and a filter outlet, and the gas-liquid separator outlet is connected to the filter inlet; the heater comprises a heater inlet and a heater outlet, and the filter outlet is connected to the heater inlet; and the membrane separation device comprises a membrane separation device inlet and a first membrane separation device outlet, the heater outlet is connected to the membrane separation device inlet, and the membrane separation device first outlet is connected to the chloromethane tower.

[0007] Optionally, the condenser further includes a condenser drain port.

[0008] Optionally, the gas-liquid separator further includes a liquid discharge port of the gas-liquid separator.

[0009] Optionally, the methyl chloride recovery system further includes a recovery tank respectively connected to the drain port of the condenser and the drain port of the gas-liquid separator.

[0010] Optionally, the condenser is a primary condenser; the methyl chloride recovery system also includes a deep condenser connected between the primary condenser and the gas-liquid separator.

[0011] Optionally, the condenser outlet is connected to the gas-liquid separator inlet through the deep condenser.

[0012] Optionally, a valve is further provided on the communication pipe between the outlet of the gas-liquid separator and the inlet of the filter to control the communication state between the gas-liquid separator and the filter.

[0013] Optionally, the membrane separation device further comprises a second outlet of the membrane separation device for discharging tail gas; the chloroform recovery system further comprises a tail gas treatment device, and the second outlet of the membrane separation device is connected to the tail gas treatment device.

[0014] Optionally, the methyl chloride recovery system also includes a compressor arranged between the membrane separation device and the methyl chloride tower, and the first outlet of the membrane separation device is connected to the methyl chloride tower through the compressor; the compressor includes a compressor inlet and a compressor outlet, the compressor inlet is connected to the first outlet of the membrane separation device, and the compressor outlet is connected to the methyl chloride tower.

[0015] Optionally, an organic vapor separation membrane is provided in the membrane separation device.

[0016] The technical solution adopted by the utility model can achieve the following beneficial effects:

[0017] The methyl chloride recovery system provided by the present application is provided with a filter, a heater and a membrane separation device in sequence after the gas-liquid separator, so that when the non-condensable gas separated by the gas-liquid separator passes through the filter, the filter can filter out the solid particle impurities (for example, iron filings, etc.) mixed in the circulating gas to prevent these solid particles from subsequently clogging the separation membrane in the membrane separation device, and then the non-condensable gas coming out of the filter is heated to a temperature suitable for membrane separation by the heater, and finally the methyl chloride in the non-condensable gas is selectively separated and recovered by the membrane separation device. Such a methyl chloride recovery system can effectively improve the recovery efficiency of methyl chloride in the methyl chloride recovery system, and the whole process has low safety risks and a green and environmentally friendly treatment method. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0019] Figure 1 It is a schematic diagram of a chloromethane recovery system according to an embodiment of the present utility model.

[0020] The following are the descriptions of the reference numerals:

[0021] 10 Methyl Chloride Tower

[0022] 20 Condenser

[0023] 30 Gas-Liquid Separator

[0024] 40 Filters

[0025] 50 Heater

[0026] 60 Membrane separation equipment

[0027] 70 Deep Condenser

[0028] 80 Recycling Tank

[0029] 90 valve

[0030] 100 Compressor

[0031] 110 Exhaust gas treatment equipment DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0033] According to one embodiment of the present application, a chloromethane recovery system is provided, which may include a chloromethane tower 10, a condenser 20, a gas-liquid separator 30, a filter 40, a heater 50 and a membrane separation device 60 connected in sequence. The chloromethane tower 10 contains a mixed gas containing chloromethane introduced from the outlet of a compressor 100 (mainly used to balance the pressure of the front and rear systems), and the components of the mixed gas are calculated by volume, mainly including 70%-80% of chloromethane, 10%-20% of nitrogen, methane and methylchlorosilane monomers, and the rest of other unknown components. The pressure of the chloromethane tower 10 is usually set in the range of 0.8-1.0Mpa. The condenser 20 may include a condenser inlet, a condenser outlet and a condenser drain port. The outlet end of the chloromethane tower 10 is connected to the inlet of the condenser to transport the mixed gas containing chloromethane in the chloromethane tower 10 to the condenser 20. The temperature of the condenser 20 is usually set at 25-35°C. At this temperature, most of the chloromethane gas in the mixed gas containing chloromethane in the condenser 20 is condensed into liquid and discharged from the condenser drain port, but there is still a part of the gas that is not condensed. This part of the uncondensed gas continues to be transported from the condenser outlet to the gas-liquid separator 30. The gas-liquid separator 30 may include a gas-liquid separator inlet, a gas-liquid separator outlet and a gas-liquid separator drain port. The condenser outlet is connected to the gas-liquid separator inlet. The uncondensed gas in the condenser 20 enters the gas-liquid separator 30 from the gas-liquid separator inlet through the condenser outlet. Since some liquid is entrained in the uncondensed gas in the condenser 20, when it enters the gas-liquid separator 30, gas and liquid are separated in the gas-liquid separator 30. The gas after gas-liquid separation is further transported to the filter 40 through the gas-liquid separator outlet, and the liquid after gas-liquid separation is discharged through the gas-liquid separator drain port. The filter 40 may include a filter inlet and a filter outlet. The gas-liquid separator outlet is connected to the filter inlet to deliver the gas after gas-liquid separation from the gas-liquid separator 30 to the filter 40. The filter 40 is provided with a filter screen with a filtering accuracy of about 1 micron. Therefore, the solid particle impurities mixed in the gas flow can be filtered out by the filter 40. These solid particle impurities can be iron filings from the pipeline, etc. The filtering by the filter 40 can prevent these solid particles from subsequently clogging the separation membrane in the membrane separation device 60, thereby helping to improve the recovery efficiency of methyl chloride and extend the service life of the separation membrane in the membrane separation device 60. The gas passing through the filter 40 can be further delivered to the heater 50 through the filter outlet.The heater 50 may include a heater inlet and a heater outlet, the filter outlet is connected to the heater inlet to transport the gas passing through the filter 40 to the heater 50, the temperature of the heater 50 is generally set in the range of 40 to 50°C, the temperature of the non-condensable gas discharged through the filter outlet of the filter 40 is between -10 and 10°C, and the temperature of the non-condensable gas is raised to 40 to 50°C by the heater 50 and then further transported to the membrane separation device 60 through the heater outlet. The membrane separation device 60 may include a membrane separation device inlet, a first membrane separation device outlet, and a second membrane separation device outlet for discharging tail gas, the heater outlet is connected to the membrane separation device inlet to further transport the gas in the heater 50 to the membrane separation device 60, and the first membrane separation device outlet is connected to the chloromethane tower 10. Considering that the optimal operating temperature of the separation membrane in the membrane separation device 60 is 40 to 50°C, the separation membrane cannot selectively separate the chloromethane gas if the temperature is too low, and the separation membrane will be damaged if the temperature is too high, therefore, the separation efficiency of the separation membrane in the membrane separation device 60 can be greatly improved by arranging the heater 50 before the membrane separation device 60. When the non-condensable gas passes through the membrane separation device 60, since the separation membrane has permeation selectivity for the methyl chloride gas in the non-condensable gas, most of the methyl chloride gas (for example, 90%) can selectively permeate through the separation membrane, while the nitrogen and methane in the non-condensable gas cannot permeate through the separation membrane or only a very small amount can permeate through the separation membrane, thereby achieving selective separation of the methyl chloride gas. The part of the gas (mainly nitrogen and methane) that has not permeated through the separation membrane is further transported to the tail gas treatment device 110 through the second outlet of the membrane separation device for further tail gas treatment, while the gas that permeates through the separation membrane can be discharged to the compressor 100 through the first outlet of the membrane separation device, and then further transported from the compressor 100 to the methyl chloride tower 10 and the above cycle is performed again to finally achieve the purification and recovery of the methyl chloride contained therein. Specifically, the compressor 100 can be arranged between the membrane separation device 60 and the methyl chloride tower 10, and the first outlet of the membrane separation device is connected to the methyl chloride tower 10 through the compressor 100. The compressor 100 may include a compressor inlet and a compressor outlet. The compressor inlet is communicated with the first outlet of the membrane separation device, and the compressor outlet is communicated with the methyl chloride tower 10.

[0034] In another embodiment, the methyl chloride recovery system may further include a recovery tank 80 respectively connected to the drain port of the condenser and the drain port of the gas-liquid separator to collect the condensed liquid discharged from the drain port of the condenser and the drain port of the gas-liquid separator to achieve the recovery of the condensed methyl chloride liquid therein.

[0035] In another embodiment, the condenser 20 may be a primary condenser. In order to further improve the condensation effect, the methyl chloride recovery system further includes a deep condenser 70 connected between the primary condenser (i.e., the condenser 20) and the gas-liquid separator 30 to achieve secondary condensation of the mixed gas containing methyl chloride. The condenser outlet may be connected to the gas-liquid separator inlet through the deep condenser 70 to further transport the non-condensable gas after the secondary condensation to the gas-liquid separator 30.

[0036] In another embodiment, a valve 90 can be set between the gas-liquid separator 30 and the filter 40 to control the circulation state and air flow rate of the gas in the pipeline. Specifically, the valve 90 can be set on the connecting pipeline between the gas-liquid separator outlet and the filter inlet to control the connection state of the gas-liquid separator 30 and the filter 40.

[0037] In order to effectively improve the recovery efficiency of methyl chloride in the methyl chloride recovery system, in one embodiment, an organic vapor separation membrane is provided in the membrane separation device 60, wherein the organic vapor separation membrane has different permeation rates for methyl chloride gas and other impurity gases, thereby selectively separating methyl chloride gas from light components such as nitrogen and methane. Therefore, by providing the membrane separation device 60, most of the methyl chloride can be effectively recovered, thereby further reducing the loss of methyl chloride, thereby improving the recovery efficiency of methyl chloride in the methyl chloride recovery system.

[0038] In the chloromethane recovery system, a membrane separation device 60 is added after the tail gas is discharged. The membrane separation device 60 recovers the gas and enters the compressor inlet. After passing through the compressor 100, the gas enters the chloromethane tower 10 again to recover the chloromethane. During this process, the processing capacity of the chloromethane tower 10 will increase. However, when the cycle reaches equilibrium, the processing capacity of the chloromethane tower 10 will also reach a maximum.

[0039] In summary, according to the methyl chloride recovery system of the present application, a filter 40, a heater 50 and a membrane separation device 60 are sequentially arranged after the gas-liquid separator 30, and the solid particle impurities (such as iron filings from the pipeline, etc.) mixed in the non-condensable gas are filtered out by the filter 40 to prevent these solid particles from subsequently clogging the separation membrane in the membrane separation device 60, and then, the heater 50 heats the non-condensable gas coming out of the filter 40 to a temperature suitable for membrane separation, ensuring the optimal working conditions of the membrane separation device 60 to selectively separate and recover the methyl chloride in the non-condensable gas. Therefore, such a system can effectively improve the recovery efficiency of methyl chloride in the methyl chloride recovery system, and the whole process has low safety risks and a green and environmentally friendly treatment method.

[0040] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A chloromethane recovery system, characterized in that: It includes a chloromethane tower, a condenser, a gas-liquid separator, a filter, a heater and a membrane separation device which are connected in sequence; in: A condenser, comprising a condenser inlet and a condenser outlet, wherein the methyl chloride tower is connected to the condenser inlet; A gas-liquid separator, comprising a gas-liquid separator inlet and a gas-liquid separator outlet, wherein the condenser outlet is connected to the gas-liquid separator inlet; A filter, comprising a filter inlet and a filter outlet, wherein the gas-liquid separator outlet is in communication with the filter inlet; a heater comprising a heater inlet and a heater outlet, the filter outlet being in communication with the heater inlet; and The membrane separation device comprises a membrane separation device inlet and a membrane separation device first outlet, the heater outlet is communicated with the membrane separation device inlet, and the membrane separation device first outlet is communicated with the methyl chloride tower.

2. The methyl chloride recovery system according to claim 1, characterized in that: The condenser also includes a condenser drain port.

3. The methyl chloride recovery system according to claim 2, characterized in that: The gas-liquid separator further comprises a gas-liquid separator liquid discharge port.

4. The methyl chloride recovery system according to claim 3, characterized in that: The methyl chloride recovery system also includes a recovery tank which is connected to the condenser drain port and the gas-liquid separator drain port respectively.

5. The methyl chloride recovery system according to claim 1, characterized in that: The condenser is a primary condenser; The methyl chloride recovery system also includes a deep condenser connected between the primary condenser and the gas-liquid separator.

6. The methyl chloride recovery system according to claim 5, characterized in that: The condenser outlet is communicated with the gas-liquid separator inlet through the deep condenser.

7. The methyl chloride recovery system according to claim 1, characterized in that: A valve is also provided on the communication pipeline between the outlet of the gas-liquid separator and the inlet of the filter to control the communication state of the gas-liquid separator and the filter.

8. The methyl chloride recovery system according to claim 1, characterized in that: The membrane separation device further comprises a second outlet of the membrane separation device for discharging tail gas; The methyl chloride recovery system further comprises a tail gas treatment device, and the second outlet of the membrane separation device is in communication with the tail gas treatment device.

9. The methyl chloride recovery system according to claim 1, characterized in that: The methyl chloride recovery system further comprises a compressor disposed between the membrane separation device and the methyl chloride tower, and the first outlet of the membrane separation device is connected to the methyl chloride tower through the compressor; The compressor comprises a compressor inlet and a compressor outlet, wherein the compressor inlet is communicated with the first outlet of the membrane separation device, and the compressor outlet is communicated with the methyl chloride tower.

10. The methyl chloride recovery system according to claim 1, characterized in that: The membrane separation device is provided with an organic vapor separation membrane.

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