TWI574726B - Solvent recycling device - Google Patents

Description

Solvent recovery unit

A solvent recovery device, especially for trapping organic gas molecules in an exhaust pipe, using a diffusion method to spray a low temperature waterfall and using Henry's law to improve molecular solubility, increasing solvent concentration and achieving environmental protection treatment efficiency, and utilizing Brown The principle of motion is to use a high-efficiency defogging tower to treat submicron aerosol particles to achieve a high recovery efficiency solvent recovery unit.

In the process of the general electronics industry or the traditional chemical industry, it is often necessary to use a large amount of chemical solvents, so that exhaust gas containing organic gas molecules or suspended particles is generated, and the exhaust gas system needs to be purified by a plurality of procedures before being discharged. Including using a washing tower or an activated carbon molecular sieve unit, the separated organic gas molecules are absorbed in a carrier (for example, a washing liquid or activated carbon), and the washing tower is taken as an example, and is used in a process exhaust gas containing hydrocarbons and alcohols. When the exhaust gas of an organic solvent such as an ether, a copper, a carboxylic acid, a valine acid or an aromatic compound is inferior, the collection efficiency is poor, and usually only 30% of the organic solvent is recovered; therefore, a manufacturer may add an exhaust gas to the exhaust gas inlet pipe. The condensing tube is installed to first cool the exhaust gas at the upstream end of the washing tower to increase the trapping amount of organic gas molecules in the washing tower. Therefore, the condensing tube must have sufficient surface area to provide contact with organic gas molecules to achieve the effect of cooling, but Increasing the size, maintenance and installation cost of the equipment, and the collection efficiency is still not ideal, the exhaust gas can not be purified completely and is not conducive to organic solvents. Income reuse.

The object of the present invention is to use a cooling device to cool the washing water, to contact the solvent molecules in a diffusion manner while using Henry's law, thereby increasing the solvent collection concentration; moreover, the overall equipment is simplified, the maintenance is facilitated, and the installation cost is reduced.

For the above purposes, the solvent recovery apparatus of the present invention includes a solvent recovery column and a cooling device. The solvent recovery tower is connected with an exhaust gas inlet pipe and an exhaust pipe at the top of the tower, and a sprayer is arranged above the tower, the bottom of the tower has a recovery tank for accommodating the washing water, and the outside of the tower is provided with a circulation of the communication recovery tank and the atomizer. a tube, and a motor connected to the circulation tube, wherein the recovery tank is connected with a first circulation line and a recovery tube; the cooling device has a liquid storage tank, a freezing main unit, a heat exchanger, and a tank for connecting the liquid storage tank, the freezing main unit and the heat a second circulation line of the exchanger, the second circulation line is provided with a circulating liquid motor, the liquid storage tank is connected to the freezing host, the freezing host cools the cooling liquid and the cryogenic cooling liquid is sent to the heat exchanger, and the heat exchanger is connected to the recovery tank. In the first circulation pipeline, the low-temperature cooling liquid supplied by the freezing main body exchanges heat with the washing water of the recovery tank, and the cooling liquid is recycled to the storage tank for recycling; the low-temperature cooling liquid supplied to the solvent recovery tower by the cooling device The washing water is cooled and cooled, and the low-temperature washing water is sprayed by the diffusion method to contact the solvent molecules of the exhaust gas and change the Henry's constant to increase the partial pressure of the solvent molecules. Improve their solubility, high solvent trapping efficiency.

The exhaust pipe of the solvent recovery tower is further connected with a defogging tower, and a sprayer is arranged above the defogging tower, and then the Brownian motion principle can be used to treat the submicron aerosol particles in the defogging tower dissolved in the washing water recovery solvent, so that The liquid return pipe provided at the bottom of the tower for connecting the recovery tank can return the washing water in the defogging tower to the recovery tank, and then exchange heat with the low temperature cooling liquid; the exhaust pipe is connected to the tower side and connected to the exhaust gas. The tube is used to pump a blower that purifies the air.

The aforementioned cryogenic coolant system includes water or an antifreeze solution.

The temperature of the low-temperature cooling liquid is 10 ° C or lower, preferably 5 ° C or lower, more preferably 0 ° C or lower.

1‧‧‧ solvent recovery tower

11‧‧‧Exhaust air intake pipe

12‧‧‧Exhaust pipe

13‧‧‧ sprayer

14‧‧‧Recycling tank

15‧‧‧Circulation tube

16‧‧‧Motor

17‧‧‧First circulation line

171‧‧‧Motor

18‧‧‧Recycling tube

181‧‧‧ valve

2‧‧‧Cooling device

21‧‧‧ liquid storage tank

22‧‧‧Freezer

23‧‧‧ heat exchanger

24‧‧‧Second circulation line

241‧‧‧First line

242‧‧‧Second line

243‧‧‧ third pipeline

25‧‧‧Circulating fluid motor

26‧‧‧Valves

27‧‧‧Flow Controller

3‧‧‧Defogging tower

31‧‧‧ sprayer

32‧‧‧Return tube

33‧‧‧Exhaust pipe

34‧‧‧Blowers

4‧‧‧Liquid supply device

41‧‧‧Supply tube

411‧‧‧Control valve

42‧‧‧Supply tube

421‧‧‧Control valve

5‧‧‧temperature sensor

6‧‧‧Level switch

7‧‧‧Recycling system

The first figure is a flow chart of a preferred embodiment of the invention.

Referring to the first figure, there is shown a preferred embodiment of the solvent recovery apparatus of the present invention. The solvent recovery device includes a solvent recovery tower 1, a cooling device 2, and a defogging tower 3, wherein:

The solvent recovery tower 1 is connected with an exhaust gas intake pipe 11 and an exhaust pipe 12 at the top of the tower. The sprayer 13 is arranged above the tower, and the bottom of the tower has a recovery tank 14 for accommodating washing water, and a communication recovery is provided outside the tower. a circulation pipe 15 of the tank 14 and the atomizer 13, and a motor 16 connected to the circulation pipe 15, and the recovery tank 14 is connected with a first circulation line 17 and a recovery pipe 18, and the recovery pipe 18 is provided with a valve 181, a first circulation line 17 is provided with a motor 171. Further, the recovery tank 14 is provided with a level switch 6 to ensure the maintenance of the level of the wash water level.

The cooling device 2 has a liquid storage tank 21, a freezing main unit 22, a heat exchanger 23, and a second circulation line 24 for connecting the liquid storage tank 21, the freezing main unit 22 and the heat exchanger 23, wherein the second circulation line 24 The first pipeline 241, the second pipeline 242 and the third pipeline 243 are connected. The first pipeline 241 is connected to the liquid storage tank 21 and the freezing main unit 22, and the second pipeline 242 is connected to the freezing main unit 22 and the heat exchanger 23. The third line 243 is connected to the liquid storage tank 21 and the heat exchanger 23, the second line 242 of the second circulation line 24 is provided with a circulating liquid motor 25, and the second circulating line 24 is provided with a plurality of numbers for adjusting the flow rate. The valve 26 and the flow controller 27, and the heat exchanger 23 is connected to the first circulation line 17 of the recovery tank 14 of the solvent recovery tower 1; the storage tank 21 is connected to the refrigeration unit 22 by the first line 241 for supplying the cooling liquid The freezing main unit 22 is cooled, and the freezing main unit 22 conveys the low-temperature cooling liquid to the heat exchanger 23 by the second line 242, and then heat-exchanges the washing water of the recovery tank 14 with the low-temperature cooling liquid supplied from the freezing main unit 22, and cools The liquid is again recovered by the third line 243 to the reservoir 21 for recycling. In addition, The first circulation line 17 and the second circulation line 24 are provided with a plurality of temperature sensors 5, and the temperature sensor 5 detects the preset temperature value, and provides the cooling device by automatic control or manual adjustment. 2 temperature control.

The center of the tower of the defogging tower 3 is connected to the exhaust pipe 12 of the solvent recovery tower 1, and a sprayer 31 is disposed above the tower of the mist removing tower 3, and the bottom of the tower is connected to a liquid return pipe 32 connected to the recovery tank 14 for supply. The washing water in the mist removing tower 3 is returned to the recovery tank 14 to exchange heat with the low-temperature cooling liquid, and an exhaust pipe 33 and a blower 34 connected to the exhaust pipe 33 for pumping the purified air are connected to the tower side.

The state of use of the solvent recovery device is that the cooling device 2 and the defogging tower 3 are connected to a liquid supply device 4 in advance. The liquid supply device 4 has two supply pipes (41, 42) connected to the storage device of the cooling device 2. The liquid tank 21, the supply pipe 42 is connected to the atomizer 31 of the defogging tower 3, and the supply pipe (41, 42) controls the flow rate of the supplied liquid by using the set control valve (411, 421), and the liquid used can be pure. A fluid such as water, antifreeze solution or sodium chloride solution is preferred to maintain fluidity at low temperatures. The temperature of the low-temperature cooling liquid supplied from the freezing main unit 22 may be 10 ° C or lower, preferably 5 ° C or lower, more preferably 0 ° C or lower.

The temperature of the cryogenic cooling liquid provided by the cooling device 2 is to continuously exchange heat with the washing water in the recovery tank 14, so that the washing water can be kept at a low temperature; when the process exhaust gas is entered into the solvent recovery tower 1 by the exhaust gas inlet pipe 11 The first stage of solvent trapping is performed, and the washing water in the recovery tank 14 is sprayed downward by the atomizer 13 to contact the upward flowing exhaust gas, and the washing water cooled by the cooling device 2 is used to reduce the kinetic energy of the solvent molecules in the exhaust gas and change the Henry's law. The proportional constant increases the partial pressure of the solvent molecules to increase the solubility thereof, and the diffusion of the washing water in the spray state increases the contact frequency of the washing water with each solvent molecule, thereby capturing a large amount of solvent molecules and dissolving in the washing water, repeatedly The trapping efficiency of the solvent in the exhaust gas is made 70% or more, and the washing water trapped with the solvent is sent to the recovery system 7 by the recovery pipe 18 to perform solvent back. Receiving treatment; continued, if the liquid of the liquid supply device 4 is pure water, it can be further used as the washing water of the defogging tower 3, and the exhaust gas collected through the first stage solvent is further introduced into the demisting tower 3 by the exhaust pipe 12. The second micron aerosol particles in the defogging tower 3 are treated by the Brownian motion principle, and the washing water is sprayed by the atomizer 31 of the defogging tower 3, so that the water mist is again contacted with the solvent molecules of the exhaust gas to capture the solvent molecules, and the submicron The aerosol particles are dissolved in the washing water to recover the solvent, and the washing water absorbing the solvent is returned to the recovery tank 14 by the liquid return pipe 32, and the purified air is discharged from the exhaust pipe 33.

Therefore, the present invention is capable of solving the deficiencies and shortcomings of the prior art. The key technology is that after the heat exchange of the washing water by the cooling device 2, the washing water can be kept at a very low temperature to capture the solvent molecules of the exhaust gas. In order to reduce the molecular kinetic energy by diffusion and low temperature, the solvent collection efficiency is greatly increased to over 70%, and the lower the lower the collection efficiency, the better the solvent recovery; in addition, the cooling device 2 of the present invention uses the liquid storage tank 21. The freezing main unit 22 and the heat exchanger 23 continuously reduce the temperature of a cooling liquid under circulation and exchange heat with the washing water, thereby having an energy-saving effect, and the structure of the cooling device 2 is simple and advantageous for zooming the field space, and even more at the same time. With the high-efficiency defogging tower 3, the Brownian motion principle is used to simultaneously treat the sub-micron aerosol particle recovery solvent, which can improve the solvent recovery efficiency, and the maintenance and operation control are more favorable.

1‧‧‧ solvent recovery tower

11‧‧‧Exhaust air intake pipe

12‧‧‧Exhaust pipe

13‧‧‧ sprayer

14‧‧‧Recycling tank

15‧‧‧Circulation tube

16‧‧‧Motor

17‧‧‧First circulation line

171‧‧‧Motor

18‧‧‧Recycling tube

181‧‧‧ valve

2‧‧‧Cooling device

21‧‧‧ liquid storage tank

22‧‧‧Freezer

23‧‧‧ heat exchanger

24‧‧‧Second circulation line

241‧‧‧First line

242‧‧‧Second line

243‧‧‧ third pipeline

25‧‧‧Circulating fluid motor

26‧‧‧Valves

27‧‧‧Flow Controller

3‧‧‧Defogging tower

31‧‧‧ sprayer

32‧‧‧Return tube

33‧‧‧Exhaust pipe

34‧‧‧Blowers

4‧‧‧Liquid supply device

41‧‧‧Supply tube

411‧‧‧Control valve

42‧‧‧Supply tube

421‧‧‧Control valve

5‧‧‧temperature sensor

6‧‧‧Level switch

7‧‧‧Recycling system

Claims (10)

A solvent recovery device comprises: a solvent recovery tower connected with an exhaust gas inlet pipe and an exhaust pipe at the top of the tower, a sprayer is arranged above the tower, and a recovery tank for accommodating the wash water is arranged at the bottom of the tower, and the tower is provided outside the tower a circulation pipe connecting the recovery tank and the atomizer, and a motor connected to the circulation pipe, and the recovery tank is connected with the first circulation pipeline and the recovery pipeline; the cooling device has a liquid storage tank, a freezing host, a heat exchanger, and is used for connecting and storing a second circulation line of the liquid tank, the freezing main unit and the heat exchanger, and a second circulating line is provided with a circulating liquid motor, the liquid storage tank is connected to the freezing host and the cooling liquid is supplied to the freezing host for cooling, and the freezing main body is cooled by the low temperature. The liquid is transported to the heat exchanger, and the heat exchanger is connected to the first circulation pipeline of the recovery tank, and the low-temperature cooling liquid supplied by the refrigeration main body exchanges heat with the washing water of the recovery tank, and the cooling liquid is recycled to the storage tank for recycling; The washing water of the solvent recovery tower is cooled and cooled by the low-temperature cooling liquid supplied by the cooling device, and the low-temperature washing water and the exhaust gas are sprayed by diffusion. Contacting the solvent molecules and molecules to reduce the kinetic energy for solvent trap. The solvent recovery device according to claim 1, wherein the temperature of the cryogenic cooling liquid supplied by the refrigeration main unit is 10 ° C or lower. The solvent recovery device according to claim 1, wherein the temperature of the cryogenic cooling liquid supplied by the refrigeration main unit is 5 ° C or lower. The solvent recovery device of claim 1, wherein the low temperature coolant system comprises water or an antifreeze solution. The solvent recovery device of claim 4, wherein the temperature of the cryogenic cooling liquid is below 0 °C. The solvent recovery device of claim 1, wherein the exhaust pipe of the solvent recovery tower is further connected to a gas treated by a Brownian motion principle. a mist removing tower for sol particles, a sprayer disposed above the mist removing tower, and a liquid returning pipe connected to the recovery tank for connecting the washing water in the mist removing tower to the recovery tank for heat with the low temperature cooling liquid Exchanging, the tower side is connected with an exhaust pipe and a blower connected to the exhaust pipe for pumping purified air. The solvent recovery device according to claim 6, wherein the temperature of the cryogenic cooling liquid supplied by the refrigeration main unit is 10 ° C or lower. The solvent recovery device according to claim 6, wherein the temperature of the cryogenic cooling liquid supplied by the refrigeration main unit is 5 ° C or lower. The solvent recovery device of claim 6, wherein the low temperature coolant system comprises water or an antifreeze solution. The solvent recovery device according to claim 9, wherein the temperature of the cryogenic cooling liquid is below 0 °C.