Tail gas treatment device and chemical production system

Abstract

The tail gas treatment device comprises an alkaline washing tower, a gas-liquid separation unit and a membrane adsorption unit which are arranged in sequence. The gas-liquid separation unit comprises a first condenser, a liquid collection tank and a gas-liquid separator which are arranged in sequence, the first condenser and the gas-liquid separator are both used for condensing the tail gas subjected to alkali washing, and the liquid collection tank is connected with the first condenser and the gas-liquid separator at the same time; the membrane adsorption unit is used for adsorbing and collecting an organic solvent in the tail gas. Acid substances in the tail gas are neutralized by alkali liquor in the alkali washing tower, then the tail gas is subjected to primary condensation through the first condenser and secondary condensation through the gas-liquid separator in sequence, water vapor in the tail gas is removed, it can be ensured that the membrane adsorption unit effectively adsorbs the organic solvent in the tail gas, and the recovery rate of the organic solvent is increased. The utility model further discloses a chemical production system. The device and the production system can be used for treating tail gas containing chlorine and silicon organic solvents and tail gas generated in preparation of surfactants (such as cocamidopropyl betaine).

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tail gas treatment, and particularly relates to a tail gas treatment device and a chemical production system. BACKGROUND

[0002] Various tail gases are generated in the chemical production process, and the tail gas containing organic solvents is usually treated by combustion, but the combustion of the tail gas containing chlorine and silicon-containing organic solvents will cause corrosion of the equipment, so the activated carbon is usually used for adsorption. However, the activated carbon will also adsorb other substances, thereby reducing the adsorption rate of the activated carbon to the organic solvents and affecting the recovery rate of the organic solvents. CONTENT OF THE UTILITY MODEL

[0003] In order to solve the problem of low recovery rate of the organic solvents in the existing tail gas containing organic solvents, the application provides a tail gas treatment device and a chemical production system with a high recovery rate of organic solvents.

[0004] The technical scheme provided by the application is as follows:

[0005] A tail gas treatment device comprises:

[0006] an alkali washing tower;

[0007] a gas-liquid separation unit comprising a first condenser, a liquid collection tank and a gas-liquid separator arranged in sequence downstream of the alkali washing tower, wherein the first condenser and the gas-liquid separator are both used for condensing the tail gas subjected to alkali washing, and the liquid collection tank is connected with the first condenser and the gas-liquid separator at the same time;

[0008] a membrane adsorption unit arranged downstream of the gas-liquid separator and used for adsorbing the organic solvents in the collected tail gas.

[0009] Further, the liquid collection tank comprises a first input end, an output end and a second input end, and the first condenser is connected with the first input end.

[0010] The gas-liquid separator comprises an input port, a gas phase outlet and a liquid phase outlet, the output end is connected with the input port, the gas phase outlet is connected with the membrane adsorption unit, and the liquid phase outlet is connected with the second input end.

[0011] Further, the outlet of the first condenser is located above the first input end, and the liquid phase outlet is located above the second input end.

[0012] Further, a jacket cooling structure is arranged outside the gas-liquid separator to condense the gas in the gas-liquid separator.

[0013] Further, the membrane adsorption unit comprises a membrane separator connected with the gas-liquid separation unit, for separating the organic solvent and the non-condensable gas in the tail gas, and a solvent collection tank connected with the membrane separator, for collecting the organic solvent.

[0014] Further, the membrane adsorption unit further comprises a second condenser arranged between the membrane separator and the solvent collection tank, for condensing the organic solvent.

[0015] Further, the tail gas treatment device further comprises a circulating pump and a circulating condenser, the circulating pump having one end connected with the caustic washing tower and the other end connected with the circulating condenser, the circulating condenser being connected with the caustic washing tower, the circulating pump being used for guiding the caustic solution to flow in the caustic washing tower and the circulating condenser in a circulating manner, and the circulating condenser being used for condensing and cooling the caustic solution.

[0016] Further, the tail gas treatment device further comprises a fan arranged between the caustic washing tower and the gas-liquid separation unit, and the height of the outlet end of the fan is higher than the height of the inlet end of the gas-liquid separation unit.

[0017] Further, the tail gas treatment device further comprises a water seal tank arranged downstream of the membrane adsorption unit.

[0018] A chemical production system comprising the tail gas treatment device as described above.

[0019] With the tail gas treatment device as described above, the tail gas generated by the drying kettle in the workshop enters the caustic washing tower, the caustic solution in the caustic washing tower neutralizes the acidic substances in the tail gas, then the tail gas enters the first condenser for preliminary condensation, the non-condensable gas and the liquid generated by condensation both enter the liquid collection tank, then the gas enters the gas-liquid separator for further condensation, the condensed liquid flows back to the liquid collection tank, and the non-condensable gas enters the membrane adsorption unit so that the organic solvent therein is adsorbed and collected. Compared with the existing activated carbon adsorption, the device neutralizes and removes the acidic substances in the tail gas through the caustic washing tower, and avoids a large amount of water vapor from entering the membrane adsorption unit by arranging the gas-liquid separation device, thereby ensuring that the membrane adsorption unit effectively adsorbs the organic solvent in the tail gas and improving the recovery rate of the organic solvent. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application and are used to explain the present application, but do not constitute a limitation on the present application.

[0021] Figure 1 The structure schematic diagram of the tail gas treatment device provided by an embodiment of the present application.

[0022] Label explanation:

[0023] 110. Alkali washing tower; 111. Circulating pump; 112. Circulating condenser; 113. Fan; 120. Gas-liquid separation unit; 121. First condenser; 122. Liquid collection tank; 123. Gas-liquid separator; 130. Membrane adsorption unit; 131. Membrane separator; 132. Solvent collection tank; 133. Second condenser; 140. Water seal tank. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0025] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the equipment or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0026] On the one hand, this application provides a tail gas treatment device for treating tail gas containing acidic substances and organic solvents, which has a high recovery rate of organic solvents. The waste gas can be hexamethyldisiloxane vapor generated from a workshop drying kettle; or it can be organic waste gas containing silane compounds, lipid compounds, dichloromethane, or other halogenated hydrocarbons. The following description uses hexamethyldisiloxane vapor as an example.

[0027] like Figure 1 As shown, the exhaust gas treatment device includes an alkaline scrubbing tower 110, a gas-liquid separation unit 120, and a membrane adsorption unit 130. The alkaline scrubbing tower 110 is used to perform alkaline scrubbing on the exhaust gas to neutralize and remove acidic substances in the exhaust gas; the gas-liquid separation unit 120 is located downstream of the alkaline scrubbing tower 110 and is used to condense the alkaline-scrubbed exhaust gas to remove water vapor carried from the alkaline scrubbing tower 110, thus preventing water vapor from affecting the subsequent absorption of organic matter; the membrane adsorption unit 130 is located downstream of the gas-liquid separation unit 120 and is used to adsorb and collect organic solvents in the exhaust gas.

[0028] Furthermore, the gas-liquid separation unit 120 includes a first condenser 121, a liquid collection tank 122, and a gas-liquid separator 123 arranged sequentially. Both the first condenser 121 and the gas-liquid separator 122 are used to condense the tail gas after alkaline washing to remove water vapor and other substances from the tail gas. The liquid collection tank 122 is connected to both the first condenser 121 and the gas-liquid separator 123 to receive the liquid generated during condensation. The membrane adsorption unit 130 is connected to the gas-liquid separator 122.

[0029] Using the aforementioned tail gas treatment device, the tail gas generated from the workshop drying kettle enters the alkaline scrubbing tower 110. The alkaline solution in the alkaline scrubbing tower 110 neutralizes the acidic substances in the tail gas. Subsequently, the tail gas enters the first condenser 121 for preliminary condensation. Both the non-condensable gas and the liquid produced by condensation enter the liquid collection tank 122. Then, the gas enters the gas-liquid separator 123 for further condensation. The condensed liquid flows back to the liquid collection tank 122, and the non-condensable gas enters the membrane adsorption unit 130 to allow the organic solvents therein to be adsorbed and collected. Compared to existing activated carbon adsorption, this device first neutralizes and removes the acidic substances in the tail gas through the alkaline scrubbing tower 110, while simultaneously setting up a gas-liquid separation device to prevent a large amount of water vapor from entering the membrane adsorption unit 130, thereby ensuring that the membrane adsorption unit 130 effectively adsorbs the organic solvents in the tail gas and improving the recovery rate of organic solvents.

[0030] In one embodiment, the exhaust gas treatment device further includes a circulating pump 111 and a circulating condenser 112. One end of the circulating pump 111 is connected to the alkaline scrubbing tower 110, and the other end is connected to the circulating condenser 112. The circulating pump 111 pumps the alkaline solution in the alkaline scrubbing tower 110 to the circulating condenser 112 for condensation and cooling. The circulating condenser 112 is connected to the alkaline scrubbing tower 110 and returns the condensed and cooled alkaline solution to the alkaline scrubbing tower 110 to continue neutralizing acidic substances in the exhaust gas. Therefore, the circulating pump 111 is used to circulate the alkaline solution within the alkaline scrubbing tower 110 and the circulating condenser 112, ensuring that the temperature of the alkaline solution in the alkaline scrubbing tower 110 meets the requirements, thus ensuring the neutralization and removal of acidic substances in the exhaust gas. It should be noted that the KOH content of the alkaline solution in the alkaline scrubbing tower 110 is 20%~25% by mass.

[0031] In one embodiment, the exhaust gas treatment device further includes a blower 113, which is disposed between the alkaline scrubbing tower 110 and the gas-liquid separation unit 120, for guiding the alkaline-scrubbed exhaust gas to the gas-liquid separation unit 120. Further, the outlet end of the blower 113 is higher than the inlet end of the gas-liquid separation unit 120 to prevent liquid accumulation at the blower 113. It is understood that the gas-liquid separation unit 120 removes water vapor from the exhaust gas through condensation; therefore, condensate will form when the exhaust gas carrying water vapor enters the gas-liquid separation unit 120. To prevent condensate from entering the blower 113, the outlet end of the blower 113 is set to be higher than the inlet end of the gas-liquid separation unit 120. Preferably, the blower 113 is a Roots blower with an outlet pressure of 1 kPa.

[0032] In one embodiment, the liquid collection tank 122 includes a first input terminal, an output terminal, and a second input terminal, and the gas-liquid separator 123 includes an inlet, a gas phase outlet, and a liquid phase outlet. A first condenser 121 is connected to the first input terminal to allow condensed gas and initially condensed liquid to enter the liquid collection tank 122. The output terminal is connected to the inlet to allow gas to enter the gas-liquid separator 123 for further condensation. The gas phase outlet is connected to the membrane adsorption unit 130 to allow non-condensable gas to be transported to the membrane adsorption unit 130 for adsorption of organic solvents. The liquid phase outlet is connected to the second input terminal to allow the condensed liquid to flow back into the liquid collection tank 122.

[0033] Furthermore, the outlet of the fan 113 is located above the inlet of the first condenser 121, the outlet of the first condenser 121 is located above the first input end, and the liquid phase outlet is located above the second input end. Similarly, it can be determined that the gas phase outlet is located above the liquid phase outlet. For example... Figure 1 The gas phase outlet is located at the top, and the liquid phase outlet is located at the bottom. This ensures that the liquid generated after condensation flows into the liquid collection tank 122, preventing the liquid from entering the fan 113 and the membrane adsorption unit 130, and also preventing the liquid from accumulating in the first condenser 121 and the gas-liquid separator 123.

[0034] Optionally, the gas-liquid separator 123 is externally equipped with a jacketed cooling structure, i.e., a jacketed space, into which coolant is introduced to condense the gas inside the gas-liquid separator 123. Preferably, the coolant in the first condenser 121 and the jacketed cooling structure is cooling water at -5°C to ensure that water vapor in the exhaust gas is condensed into liquid, and that organic solvents that need to be recovered in the exhaust gas are not condensed into liquid. It should also be noted that in the first condenser 121 and the gas-liquid separator 123, any gaseous substances that cannot be condensed into liquid can be considered as non-condensable gases.

[0035] In one embodiment, the membrane adsorption unit 130 includes a membrane separator 131 and a solvent collection tank 132. The membrane separator 131 is connected to the gas-liquid separation unit 120, specifically to the outlet end of the gas-liquid separator 123, for separating non-condensable gases and organic solvents. The membrane separator 131 is connected to the solvent collection tank 132 to transport the separated organic solvents to the solvent collection tank 132 for collection. It should be explained that when the exhaust gas passes through the membrane separator 131, the organic solvents can permeate through the solvent adsorption membrane and enter the solvent collection tank 132, while the non-condensable gases cannot permeate through the solvent adsorption membrane and are therefore directly transported downstream.

[0036] Furthermore, the membrane adsorption unit 130 also includes a second condenser 133, which is disposed between the membrane separator 131 and the solvent collection tank 132 for condensing the organic solvent, thereby enabling the solvent collection tank 132 to collect the liquid organic solvent. It is understood that in this embodiment, the condensation temperature in the second condenser 133 is lower than the condensation temperature in the first condenser 121 and the jacket cooling structure to ensure that the organic solvent is condensed into a liquid state for collection.

[0037] In one embodiment, the exhaust gas treatment device further includes a water seal tank 140, which is located downstream of the membrane adsorption unit 130. Non-condensable gases are discharged after passing through the water seal tank 140. The water seal tank 140 can serve as a backflow preventer for non-condensable gases and an anti-flame device, thereby improving the safety of the exhaust gas treatment device.

[0038] To facilitate understanding of the technical solution of this application, this document combines... Figure 1 The process flow of the exhaust gas treatment device in the above embodiments is described as follows:

[0039] The hexamethyldisiloxane vapor generated in the workshop drying kettle enters the alkaline washing tower 110. The alkaline solution in the alkaline washing tower 110 neutralizes the acidic substances in the vapor and cools the solvent (hexamethyldisiloxane) vapor through the lower temperature alkaline solution to initially remove some of the water vapor in the vapor. Subsequently, the solvent vapor enters the first condenser 121 through the blower 113 for condensation. Both the condensed liquid and gas enter the liquid collection tank 122, where the liquid is collected. The water vapor removed from the solvent vapor mixes with the vapor that evaporates again in the liquid collection tank 122 and then enters the gas-liquid separator 123, where it is condensed again. The water vapor condenses and flows back into the liquid collection tank 122, while the water vapor removed from the solvent vapor continues to be transported to the membrane separator 131. The solvent enters the second condenser 133 through the solvent adsorption membrane in the membrane separator 131, condenses into a liquid state and flows into the solvent collection tank 132 for collection; other non-condensable gases are directly transported to the water seal tank 140, and after passing through the water seal tank 140 and meeting the standards, they are discharged into the air.

[0040] In summary, the exhaust gas treatment device provided in this application has at least the following advantages:

[0041] 1. Simple structure and low equipment cost;

[0042] 2. Before recovering organic solvents, acidic substances and water vapor in the tail gas are removed to improve the adsorption rate of organic solvents in the membrane separator 131, thereby improving the recovery rate of organic solvents and extending the service life of the adsorption membrane.

[0043] Based on the exhaust gas treatment device in the above embodiments, this application also provides a chemical production system that includes the exhaust gas treatment device in the above embodiments.

[0044] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A tail gas treatment device, characterized in that, include: Alkali washing tower; The gas-liquid separation unit includes a first condenser, a liquid collection tank, and a gas-liquid separator arranged sequentially downstream of the alkaline scrubbing tower. Both the first condenser and the gas-liquid separator are used to condense the tail gas after alkaline scrubbing. The liquid collection tank is connected to both the first condenser and the gas-liquid separator. A membrane adsorption unit is located downstream of the gas-liquid separator and is used to adsorb and collect organic solvents in the exhaust gas. The membrane adsorption unit includes a membrane separator, a solvent collection tank, and a second condenser. The membrane separator is connected to the gas-liquid separation unit and is used to separate organic solvents and non-condensable gases in the exhaust gas. The solvent collection tank is connected to the membrane separator to collect organic solvents. The second condenser is located between the membrane separator and the solvent collection tank and is used to condense the organic solvents.

2. The exhaust gas treatment device according to claim 1, characterized in that, The liquid collection tank includes a first input terminal, an output terminal, and a second input terminal, and the first condenser is connected to the first input terminal; The gas-liquid separator includes an inlet, a gas phase outlet, and a liquid phase outlet. The outlet is connected to the inlet, the gas phase outlet is connected to the membrane adsorption unit, and the liquid phase outlet is connected to the second inlet.

3. The exhaust gas treatment device according to claim 2, characterized in that, The outlet of the first condenser is located above the first input terminal, and the liquid phase outlet is located above the second input terminal.

4. The exhaust gas treatment device according to claim 1, characterized in that, The gas-liquid separator is equipped with a jacketed cooling structure on the outside to condense the gas inside the gas-liquid separator.

5. The exhaust gas treatment device according to claim 1, characterized in that, The exhaust gas treatment device also includes a circulating pump and a circulating condenser. One end of the circulating pump is connected to the alkaline washing tower, and the other end is connected to the circulating condenser. The circulating condenser is connected to the alkaline washing tower. The circulating pump is used to guide the alkaline solution to circulate in the alkaline washing tower and the circulating condenser. The circulating condenser is used to condense and cool the alkaline solution.

6. The exhaust gas treatment device according to claim 1, characterized in that, The exhaust gas treatment device also includes a fan, which is located between the alkaline scrubbing tower and the gas-liquid separation unit, and the height of the outlet end of the fan is higher than the height of the inlet end of the gas-liquid separation unit.

7. The exhaust gas treatment device according to claim 1, characterized in that, The exhaust gas treatment device also includes a water seal tank, which is located downstream of the membrane adsorption unit.

8. A chemical production system, characterized in that, Includes the exhaust gas treatment device according to any one of claims 1-7.

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