Chlorinated tail gas treatment device

Abstract

The utility model provides a chlorinated tail gas treatment device. The chlorinated tail gas treatment device comprises a reaction kettle, a first condenser, a second condenser, a hydrogen chloride absorption device and an alkaline tower which are sequentially connected in series, an air compressor is arranged between the first condenser and the second condenser; the second condenser is also sequentially connected with a liquid chlorine storage tank and a reaction kettle; the hydrogen chloride absorption device is also connected with a hydrochloric acid storage tank; the heat exchange medium output end of the second condenser is further connected with the heat exchange medium input end of the first condenser. According to the device disclosed by the invention, the components in the chlorinated tail gas are separated and then recovered through matched use of the equipment, and the defect that the recovery value of acid generated by directly adopting water to absorb and treat the chlorinated tail gas in the prior art is not high is overcome. In addition, liquid chlorine obtained through condensation of the second condenser can be reused in the reaction kettle to serve as a chlorinating agent, and therefore the beneficial effect of saving resources is achieved.

Description

Technical Field

[0001] This application relates to the technical field of tail gas treatment, and particularly to a chlorinated tail gas treatment device. Background Art

[0002] Parathion-ethyl, also known as parathion, has the chemical name O,O-diethyl-O-(4-nitrophenyl) thiophosphate and is a broad-spectrum organophosphorus insecticide with the chemical formula C 10 H 14 NO5PS. The main synthesis method of parathion-ethyl is the phosphorus pentasulfide synthesis method, which uses phosphorus pentasulfide and ethanol as raw materials to synthesize O,O-diethyl thiophosphoric acid. Then, it is chlorinated with chlorine to obtain O,O-diethyl thiophosphoryl chloride, and finally, it reacts with p-nitrophenol to obtain the target product parathion-ethyl.

[0003] Among them, a large amount of chlorine-containing tail gas is generated during the chlorination stage, and its main components are hydrogen chloride and a small amount of chlorine, sulfides, and organic phosphorus, etc. Conventionally, directly using water to absorb the tail gas can obtain low-concentration hydrochloric acid. Although this method can absorb substances such as hydrogen chloride in the tail gas, the resulting acid is a mixed acid containing organic phosphorus and sulfides, and there is a strong bad smell. This acid is difficult to have other uses except for neutralization, resulting in low recovery value. Utility Model Content

[0004] This application provides a chlorinated tail gas treatment device to solve the problem of low recovery value of the acid generated by directly using water absorption to treat chlorinated tail gas as described above.

[0005] This application provides a chlorinated tail gas treatment device, including a reaction kettle, a first condenser, a second condenser, a hydrogen chloride absorption device, and an alkali washing tower connected in series in sequence;

[0006] An air compressor is arranged between the first condenser and the second condenser;

[0007] The second condenser is also connected to a liquid chlorine storage tank and the reaction kettle in sequence;

[0008] The hydrogen chloride absorption device is also connected to a hydrochloric acid storage tank;

[0009] The heat exchange medium output end of the second condenser is also connected to the heat exchange medium input end of the first condenser.

[0010] Optionally, an intermediate absorption tower is also arranged between the second condenser and the hydrogen chloride absorption device.

[0011] Optionally, the hydrogen chloride absorption device includes a first absorption tower and a second absorption tower connected in series along the gas-phase treatment path;

[0012] In the hydrogen chloride absorption device, a fresh water tank, a second absorption tower, and a first absorption tower are connected in series along the liquid-phase treatment path;

[0013] The gas-phase output end of the second absorption tower is connected to the caustic scrubber;

[0014] The liquid-phase output end of the first absorption tower is connected to the hydrochloric acid storage tank.

[0015] Optionally, a liquid chlorine vaporizer is provided between the liquid chlorine storage tank and the reaction kettle.

[0016] Optionally, the liquid chlorine vaporizer includes a housing, and the housing is divided into a preheating zone and a vaporization zone by a partition provided inside;

[0017] A heat exchange sleeve is provided in the preheating zone. One end of the heat exchange sleeve passes through the housing and is connected to the liquid chlorine storage tank, and the other end passes through the partition and extends into the vaporization zone and is connected to a spray head.

[0018] Optionally, a heating sleeve is sleeved inside the vaporization zone. The heating sleeve is provided with a cavity inside and is connected to a heat exchange medium output device.

[0019] Optionally, the heat exchange sleeve is arranged in a coiled manner and includes an inner tube and an outer tube arranged coaxially;

[0020] Both ends of the outer tube pass through the housing, and one end is connected to the heat exchange medium output end of the heating sleeve.

[0021] The hydrogen chloride tail gas treatment device provided by the present application removes organic substances and chlorine in the tail gas by setting a first condenser and a second condenser, improves the content and purity of hydrogen chloride in the tail gas, and at the same time sets a hydrogen chloride absorption device to absorb hydrogen chloride in the treated tail gas to produce hydrochloric acid, and resourcefully utilizes hydrogen chloride in the tail gas. The device of the present application separates and recovers the components in the hydrogen chloride tail gas through the combined use of the above-mentioned equipment, and overcomes the disadvantage of low acid recovery value caused by directly using water to absorb and treat hydrogen chloride tail gas in the traditional method. In addition, the liquid chlorine condensed by the second condenser can also be reused in the reaction kettle as a chlorinating agent, so it also has the beneficial effect of saving resources. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a schematic diagram of the hydrogen chloride tail gas treatment device provided by an embodiment of the present application;

[0024] Figure 2 Schematic diagram of the chlorine-containing tail gas treatment device provided by another embodiment of the present application;

[0025] Figure 3 Schematic diagram of the chlorine-containing tail gas treatment device provided by yet another embodiment of the present application;

[0026] Figure 4 Schematic diagram of the chlorine-containing tail gas treatment device provided by still another embodiment of the present application;

[0027] Figure 5 Schematic structural diagram of the liquid chlorine vaporizer provided by an embodiment of the present application;

[0028] Figure 6 Schematic cross-sectional structural diagram of the vaporization zone provided by an embodiment of the present application;

[0029] Figure 7 Schematic cross-sectional structural diagram of the heat exchange sleeve provided by an embodiment of the present application.

[0030] Explanation of reference numerals:

[0031] 1, reaction kettle; 2, first condenser; 3, second condenser; 4, hydrogen chloride absorption device; 5, caustic scrubber; 6, air compressor; 7, intermediate absorption tower; 8, liquid chlorine vaporizer; 31, liquid chlorine storage tank; 40, hydrochloric acid storage tank; 41, first absorption tower; 42, second absorption tower; 43, fresh water tank; 81, housing; 82, partition; 83, heat exchange sleeve; 84, heating sleeve; 821, spray head; 831, inner tube; 832, outer tube. Detailed implementation manners

[0032] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts also belong to the scope of protection of the present application.

[0033] As Figure 1 shown, the present application provides a chlorine-containing tail gas treatment device, including a reaction kettle 1, a first condenser 2, a second condenser 3, a hydrogen chloride absorption device 4 and a caustic scrubber 5 connected in series in sequence;

[0034] An air compressor 6 is arranged between the first condenser 2 and the second condenser 3;

[0035] The second condenser 3 is further connected to the liquid chlorine storage tank 31 and the reaction kettle 1 in sequence;

[0036] The hydrogen chloride absorption device 4 is further connected to the hydrochloric acid storage tank 40;

[0037] The heat transfer medium output end of the second condenser 3 is also connected to the heat transfer medium input end of the first condenser 2.

[0038] The following reaction occurs during the O,O-diethylthiophosphoric acid chlorination stage:

[0039]

[0040] It can be seen that the tail gas after the reaction mainly contains the reaction product hydrogen chloride, unreacted chlorine, and a small amount of organophosphorus, sulfur, and other chlorides mixed in the tail gas.

[0041] During use, the chlorine-containing tail gas output from the reaction kettle 1, which contains unreacted chlorine, the reaction product hydrogen chloride, and a small amount of substances such as organophosphorus and sulfur, first passes through the first condenser 2 for cooling (the heat transfer medium in the first condenser 2 comes from the second condenser 3), condensing the organophosphorus, sulfur, and disulfur dichloride in it. The waste liquid obtained by condensation is centrally treated. After passing through the first condenser 2 to condense and remove substances such as organophosphorus, sulfur, and disulfur dichloride from the tail gas, the main components of the tail gas at this time are chlorine and hydrogen chloride. Then, the tail gas passes through the second condenser 3 for cooling to condense the chlorine in it. The heat transfer medium in the second condenser 3 is low-temperature refrigerated brine. The liquid chlorine obtained after condensation in the second condenser 3 is centrally stored in the liquid chlorine storage tank 31.

[0042] The main component of the tail gas after removing chlorine through condensation in the second condenser 3 is hydrogen chloride. At this time, the tail gas is input into the hydrogen chloride absorption device 4 for absorption to produce hydrochloric acid, and the obtained hydrochloric acid is input into the hydrochloric acid storage tank 40. The tail gas after absorption is discharged from the top of the tower and enters the caustic scrubbing tower 5, where the acidic substances in the tail gas are absorbed and treated with the alkali solution in it before being discharged.

[0043] The chlorinated tail gas treatment device provided by this application removes organic substances and chlorine in the tail gas by setting the first condenser 2 and the second condenser 3, improving the content and purity of hydrogen chloride in the tail gas. At the same time, a hydrogen chloride absorption device 4 is set to absorb the hydrogen chloride in the treated tail gas to produce hydrochloric acid, realizing the resource utilization of hydrogen chloride in the tail gas. Through the coordinated use of the above-mentioned equipment, the components in the chlorinated tail gas are separated and recovered, overcoming the drawback of the low acid recovery value caused by directly using water absorption to treat chlorinated tail gas in the traditional method. In addition, the liquid chlorine obtained by condensation in the second condenser 3 can also be recycled to the reaction kettle 1 for use as a chlorinating agent, thus also having the beneficial effect of saving resources.

[0044] Such as Figure 2 As shown, optionally, an intermediate absorption tower 7 is also provided between the second condenser 3 and the hydrogen chloride absorption device 4.

[0045] After the tail gas has been condensed by the second condenser 3 to remove chlorine gas, the main component in the tail gas is hydrogen chloride. Then, the tail gas that has been condensed by the second condenser 3 is introduced into the intermediate absorption tower 7. In the intermediate absorption tower 7, filter cotton is filled in the uppermost layer and the lowermost layer, and filter cotton impregnated with paraffin oil is filled in the intermediate layer. When the tail gas passes through the intermediate layer of the filter cotton impregnated with paraffin oil, trace amounts of chlorine gas and organic substances that have not been removed by the previous two condensation processes can be dissolved in the paraffin oil and further adsorbed and removed. After the tail gas has been subjected to adsorption treatment in the intermediate layer and passes through the filter cotton layer, the paraffin oil entrained in the tail gas can be intercepted and filtered, and hydrogen chloride gas with a higher cleanliness level is output.

[0046] As Figure 3 shown, optionally, the hydrogen chloride absorption device 4 includes a first absorption tower 41 and a second absorption tower 42 connected in series along the gas-phase treatment path;

[0047] In the hydrogen chloride absorption device 4, a fresh water tank 43, a second absorption tower 42, and a first absorption tower 41 are connected in series along the liquid-phase treatment path;

[0048] The gas-phase output end of the second absorption tower 42 is connected to the alkali washing tower 5;

[0049] The liquid-phase output end of the first absorption tower 41 is connected to the hydrochloric acid storage tank 40.

[0050] In this application, the tail gas that has been subjected to adsorption treatment in the intermediate absorption tower 7 is input into the first absorption tower 41 and contacts the dilute hydrochloric acid input from the second absorption tower 42 in a countercurrent manner to absorb the hydrogen chloride in the tail gas. A circulation pump can also be set to circulate the hydrochloric acid in the first absorption tower 41 to absorb the hydrogen chloride in the tail gas and thereby increase the concentration of the hydrochloric acid. The hydrochloric acid with a qualified concentration obtained by absorption is input into the hydrochloric acid storage tank 40. There is still a small amount of hydrogen chloride in the tail gas after being absorbed by the first absorption tower 41. These hydrogen chlorides are output from the top of the tower and enter the second absorption tower 42 to contact the fresh water supplied by the fresh water tank 43 in a countercurrent manner to further absorb the hydrogen chloride. The tail gas after absorption is discharged from the top of the tower and enters the alkali washing tower 5, where the acidic substances in the tail gas are absorbed and treated by the alkali solution therein. At this time, the fresh water in the tower that has absorbed hydrogen chloride forms dilute hydrochloric acid, which is input into the first absorption tower 41 for spraying to absorb the hydrogen chloride in the tail gas that has been treated by the intermediate absorption tower 7. Similarly, a circulation pump can also be set to be used in conjunction with the second absorption tower 42 to circulate the dilute hydrochloric acid in the second absorption tower 42 for spraying to absorb hydrogen chloride. When its concentration reaches a preset value, it is then input into the first absorption tower 41 for use.

[0051] As Figure 4 shown, optionally, a liquid chlorine vaporizer 8 is provided between the liquid chlorine storage tank 31 and the reaction kettle 1.

[0052] The liquid chlorine temporarily stored in the liquid chlorine storage tank 31 is vaporized in the liquid chlorine vaporizer 8 and then input into the reaction kettle 1 for reuse when it is reused as a chlorinating agent in the reaction kettle 1.

[0053] As Figure 5 shown, optionally, the liquid chlorine vaporizer 8 includes a housing 81, and the housing 81 is divided into a preheating zone and a vaporization zone by a partition plate 82 arranged inside;

[0054] A heat exchange sleeve 83 is arranged in the preheating zone. One end of the heat exchange sleeve 83 passes through the housing 81 and is connected to the liquid chlorine storage tank 31, and the other end passes through the partition plate 82 and extends into the vaporization zone and is connected to a spray head 821.

[0055] When the liquid chlorine is vaporized, it is first passed into the heat exchange sleeve 83 in the preheating zone of the liquid chlorine vaporizer 8 for heating, and then sprayed out from the spray head 821 into the vaporization zone. After being heated by the heat exchange sleeve 83, the liquid chlorine has been partially vaporized. Therefore, what is output from the spray head 821 is a gas-liquid mixture. When these gas-liquid mixtures are sprayed out, a small amount of the liquid chlorine in them is sprayed out in the form of small liquid droplets or mist.

[0056] As Figure 6 shown, optionally, a heating sleeve 84 is sleeved in the vaporization zone. The inside of the heating sleeve 84 is provided with a cavity and is connected to a heat exchange medium output device.

[0057] After being heated by the heat exchange sleeve 83, the liquid chlorine has been partially vaporized. Therefore, what is output from the spray head 821 is a gas-liquid mixture. When these gas-liquid mixtures are sprayed out, a small amount of the liquid chlorine in them is sprayed out in the form of small liquid droplets or mist. At this time, the heat provided by the heating sleeve 84 in the vaporization zone further vaporizes the liquid chlorine in the form of droplets and simultaneously heats the vaporized chlorine gas to a certain temperature. The chlorine gas vaporized in the vaporization zone is output from the liquid chlorine vaporizer 8 and enters the reaction kettle 1 for reaction.

[0058] As Figure 7 shown, optionally, the heat exchange sleeve 83 is arranged in a coiled manner and includes an inner tube 831 and an outer tube 832 arranged coaxially;

[0059] Both ends of the outer tube 832 pass through the housing 81 respectively, and one end is connected to the heat exchange medium output end of the heating sleeve 84.

[0060] In this application, when the liquid chlorine is vaporized, it is first passed into the inner tube 831 of the heat exchange sleeve 83 in the preheating zone of the liquid chlorine vaporizer 8, and the cavity between the inner tube 831 and the outer tube 832 is filled with a heating medium (such as normal temperature circulating water) to heat the liquid chlorine in the inner tube 831.

[0061] During the process of vaporizing the liquid chlorine in the liquid chlorine vaporizer 8, the heating medium in the heating sleeve 84 can be input into the cavity between the inner tube 831 and the outer tube 832 of the heat exchange sleeve 83 for preheating the liquid chlorine after being used for heating the vaporization zone.

[0062] A chlorine-containing tail gas treatment device has the following working process:

[0063] During use, the chlorine-containing tail gas output from the reactor 1 contains unreacted chlorine, reaction product hydrogen chloride, and small amounts of substances such as organic phosphorus and sulfur. The tail gas is first cooled in the first condenser 2 (the heat exchange medium in the first condenser 2 comes from the second condenser 3) to condense the organic phosphorus, sulfur, and disulfur dichloride. The condensed waste liquid is centrally treated. After the organic phosphorus, sulfur, disulfur dichloride, and other substances in the tail gas are removed by condensation in the first condenser 2, the main components in the tail gas are chlorine and hydrogen chloride at this time. Then the tail gas is cooled in the second condenser 3 to condense the chlorine. The heat exchange medium in the second condenser 3 is low-temperature refrigerated brine. The liquid chlorine obtained after condensation in the second condenser 3 is centrally stored in the liquid chlorine storage tank 31.

[0064] The main component in the tail gas after removing chlorine by condensation in the second condenser 3 is hydrogen chloride. Then the tail gas after condensation treatment in the second condenser 3 is introduced into the intermediate absorption tower 7. Filter cotton is filled in the uppermost and lowermost layers of the intermediate absorption tower 7, and filter cotton impregnated with paraffin oil is filled in the middle layer. When the tail gas passes through the middle layer of the filter cotton impregnated with paraffin oil, trace amounts of chlorine and organic substances that have not been removed by the previous two condensation processes can be dissolved in the paraffin oil and further adsorbed and removed. After the tail gas passes through the adsorption treatment of the middle layer and passes through the filter cotton layer, the paraffin oil entrained in the tail gas can be intercepted and filtered to output hydrogen chloride gas with higher cleanliness.

[0065] The tail gas after adsorption treatment in the intermediate absorption tower 7 is input into the first absorption tower 41 and contacts countercurrently with the dilute hydrochloric acid input from the second absorption tower 42 to absorb the hydrogen chloride in the tail gas. A circulation pump can also be set to circulate the hydrochloric acid in the first absorption tower 41 to absorb the hydrogen chloride in the tail gas and thus increase the concentration of the hydrochloric acid. The hydrochloric acid with qualified concentration obtained by absorption is input into the hydrochloric acid storage tank 40. There is still a small amount of hydrogen chloride in the tail gas after absorption in the first absorption tower 41. These hydrogen chlorides are output from the top of the tower and enter the second absorption tower 42 to contact countercurrently with the clear water supplied by the clear water tank 43 to further absorb the hydrogen chloride. The tail gas after absorption is discharged from the top of the tower and enters the caustic scrubber 5 to use the alkali solution therein to absorb and treat the acidic substances in the tail gas. At this time, the clear water in the tower that has absorbed hydrogen chloride forms dilute hydrochloric acid, which is input into the first absorption tower 41 for spraying to absorb the hydrogen chloride in the tail gas after treatment in the intermediate absorption tower 7. Similarly, a circulation pump used in conjunction with the second absorption tower 42 can be set to circulate the dilute hydrochloric acid in the second absorption tower 42 for spraying in the second absorption tower 42 to absorb hydrogen chloride. When its concentration reaches the preset value, it is then input into the first absorption tower 41 for use.

[0066] During the above process, the heat exchange medium in the second condenser 3 can be used for condensation in the first condenser 2 after condensing the tail gas, and the heat exchange medium in the first condenser 2 can be used for cooling the first absorption tower 41 after heat exchange to improve the absorption efficiency of chlorine gas.

[0067] The liquid chlorine temporarily stored in the liquid chlorine storage tank 31, when reused as a chlorinating agent in the reaction kettle 1, is first passed into the liquid chlorine vaporizer 8 for vaporization and then input into the reaction kettle 1 for reuse. When the liquid chlorine is vaporized, it is first passed into the inner tube 831 of the heat exchange sleeve 83 in the preheating zone of the liquid chlorine vaporizer 8. The cavity between the inner tube 831 and the outer tube 832 is filled with a heating medium (such as normal temperature circulating water) to heat the liquid chlorine in the inner tube 831, and then it is sprayed out from the nozzle 821 into the vaporization zone. After being heated by the heat exchange sleeve 83, the liquid chlorine has been partially vaporized, so what is output from the nozzle 821 is a gas-liquid mixture. When these gas-liquid mixtures are sprayed out, a small amount of the liquid chlorine in them is sprayed out in the form of small droplets or mist. At this time, the heat provided by the heating sleeve 84 in the vaporization zone further vaporizes the droplet-shaped liquid chlorine and simultaneously heats the vaporized chlorine gas to a certain temperature. The chlorine gas vaporized in the vaporization zone is output from the liquid chlorine vaporizer 8 and enters the reaction kettle 1 for reaction. An activated carbon adsorption tube can also be provided between the liquid chlorine vaporizer 8 and the reaction kettle 1 to adsorb and remove a small amount of hydrogen chloride gas, organic substances, etc. in the chlorine gas to improve the purity of the chlorine gas input into the reaction kettle 1. During the process of vaporizing the liquid chlorine in the liquid chlorine vaporizer 8, the heating medium in the heating sleeve 84 can be input into the cavity between the inner tube 831 and the outer tube 832 of the heat exchange sleeve 83 for preheating the liquid chlorine after being used for heating the vaporization zone.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A chlorine-containing tail gas treatment device, characterized in that, It includes a reactor (1), a first condenser (2), a second condenser (3), a hydrogen chloride absorption device (4) and an alkali scrubber (5) connected in series in sequence; An air compressor (6) is arranged between the first condenser (2) and the second condenser (3); The second condenser (3) is also connected to a liquid chlorine storage tank (31) and the reactor (1) in sequence; The hydrogen chloride absorption device (4) is also connected to a hydrochloric acid storage tank (40); The heat transfer medium output end of the second condenser (3) is also connected to the heat transfer medium input end of the first condenser (2).

2. The chlorine-containing tail gas treatment device according to claim 1, wherein An intermediate absorption tower (7) is also arranged between the second condenser (3) and the hydrogen chloride absorption device (4).

3. The chlorine-containing tail gas treatment device according to claim 1, characterized in that, The hydrogen chloride absorption device (4) includes a first absorption tower (41) and a second absorption tower (42) connected in series along the gas-phase treatment path in sequence; In the hydrogen chloride absorption device (4), a fresh water tank (43), the second absorption tower (42) and the first absorption tower (41) are connected in series along the liquid-phase treatment path in sequence; The gas-phase output end of the second absorption tower (42) is connected to the alkali scrubber (5); The liquid-phase output end of the first absorption tower (41) is connected to the hydrochloric acid storage tank (40).

4. The chlorination tail gas treatment device according to claim 1, characterized in that A liquid chlorine vaporizer (8) is arranged between the liquid chlorine storage tank (31) and the reactor (1).

5. The chlorine-containing tail gas treatment device according to claim 4, wherein, The liquid chlorine vaporizer (8) includes a housing (81), and the housing (81) is divided into a preheating zone and a vaporization zone by a partition plate (82) arranged inside; A heat exchange sleeve (83) is arranged in the preheating zone. One end of the heat exchange sleeve (83) passes through the housing (81) and is connected to the liquid chlorine storage tank (31), and the other end passes through the partition plate (82) and extends into the vaporization zone and is connected to a spray head (821).

6. The chlorine-containing tail gas treatment device according to claim 5, wherein, A heating sleeve (84) is sleeved in the vaporization zone. The heating sleeve (84) has a cavity inside and is connected to a heat transfer medium output device.

7. The chlorine-containing tail gas treatment device according to claim 5, wherein, The heat exchange sleeve (83) is arranged in a coiled manner and includes an inner tube (831) and an outer tube (832) arranged coaxially; Both ends of the outer tube (832) pass through the housing (81) and are arranged, and one end is connected to the heat transfer medium output end of the heating sleeve (84).

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