A device and process for treating waste gas from dinitrochlorobenzene production

Abstract

The invention relates to the technical field of dinitrochlorobenzene production, and proposes a dinitrochlorobenzene production waste gas treatment device and process, comprising an organic tail gas treatment device and a thermal oil furnace tail gas treatment device; the invention uses the organic tail gas treatment device and the thermal oil furnace tail gas treatment device to achieve classified treatment of organic tail gas generated in the dinitrochlorobenzene production process and tail gas discharged from the thermal oil furnace flue gas after gas combustion, thereby solving the technical problem that the prior art cannot achieve standard treatment of different types of tail gas.

Description

Technical Field

[0001] The invention relates to the technical field of dinitrochlorobenzene production, and specifically to a device and process for treating waste gas from dinitrochlorobenzene production. Background Art

[0002] Dinitrochlorobenzene, referred to as DNCB, is mainly used as an intermediate and polymerization aid for the preparation of dyes, medicines and pesticides. Its molecular formula is C6H3Cl(NO2)2. It has six isomers. The one that needs to be produced is 2,4-DNCB. Among the products produced with chlorobenzene as raw material, 2,4-DNCB generally accounts for about 96%, 2,6-DNCB accounts for about 3%, unnitrated mononitrochlorobenzene accounts for 0.2%, and the rest are nitration by-products. 2,4-DNCB produced with p-nitrochlorobenzene as raw material generally accounts for 99.5%, and the remaining mononitrates and by-products account for 0.5%. The six isomers of dinitrochlorobenzene will produce waste gas during the production process. In order to avoid pollution to the environment, the tail gas needs to be treated to meet the standards.

[0003] After searching, the announcement number CN217698498U discloses a tail gas treatment device used in the production process of 2,4-dinitrochlorobenzene, including a spray tower and a tail gas inlet, the lower left side of the spray tower is connected to a gas input pipeline, one end of the tail gas inlet is connected to a hot water storage cylinder, the upper left end of the hot water storage cylinder is connected to a water inlet, the lower right end of the hot water storage cylinder is connected to a water outlet, a hollow cavity is opened at the axis of the hot water storage cylinder, and a spray pipe is arranged inside the spray tower. The tail gas treatment device is provided with a hot water storage cylinder, a water inlet, a water outlet and a hollow cavity, and utilizes the mutual cooperation between them, so that the heat accompanying the tail gas can be used to heat the water in the hot water storage cylinder, and the heat can be recycled. In addition, by providing a gas treatment chamber and an activated carbon adsorption layer, harmful substances in the tail gas can be adsorbed, thereby improving the treatment effect of the tail gas.

[0004] However, the above-mentioned exhaust gas treatment device still has the following problems: the above-mentioned exhaust gas treatment device can only treat the organic exhaust gas generated in the production process of dinitrochlorobenzene. In fact, in the production process of dinitrochlorobenzene, the exhaust gas discharged from the flue gas of the thermal oil furnace is also used to generate exhaust gas after the combustion of coal gas, and the existing technology cannot achieve the standard treatment of different types of exhaust gas. Summary of the invention

[0005] The present invention provides a device and process for treating waste gas from the production of dinitrochlorobenzene, which solves the problem in the prior art that different types of tail gas cannot be treated to meet the standards.

[0006] The technical solution of the present invention is as follows: a waste gas treatment device for dinitrochlorobenzene production, including an organic tail gas treatment device and a thermal oil furnace tail gas treatment device, wherein: The organic tail gas treatment device comprises: an organic tail gas condenser for cooling the organic tail gas, a dry filter for filtering the tail gas treated by the organic tail gas condenser, a guide fan, an activated carbon tank A and an activated carbon tank B for adsorbing the tail gas treated by the dry filter through the guide fan, a desorption condenser for cooling the tail gas treated by the activated carbon tank A and the activated carbon tank B through circulation, and an oil-water separator for separating condensed water after condensation by the desorption condenser; The thermal oil furnace flue gas treatment device comprises: a urea dissolving tank for dissolving bagged urea, a urea storage tank for storing the urea solution after stirring in the urea dissolving tank, a reactor for reacting the urea solution in the urea storage tank with the introduced thermal oil furnace flue gas, an air preheater for cooling the flue gas after denitration at the bottom of the reactor, an induced draft fan, a desulfurization tower for introducing the cooled flue gas from the bottom through the induced draft fan, a lime nitration tank for preparing lime solution, a regeneration tank and a sedimentation tank for mixing the sewage at the bottom of the desulfurization tower with the lime solution in the lime nitration tank for precipitation, and a circulation tank for circulating the water from the top of the sedimentation tank into the desulfurization tower.

[0007] Based on the above-mentioned waste gas treatment device for dinitrochlorobenzene production, the present invention also proposes a waste gas treatment process for dinitrochlorobenzene production, wherein the treatment process for organic tail gas is as follows: the organic tail gas passes through an organic tail gas condenser, a dry filter, and a guide fan in sequence and then enters an activated carbon tank A, and the organic matter in the tail gas is adsorbed by the activated carbon in the activated carbon tank A and then discharged in compliance with the standards; After the activated carbon tank A has finished adsorbing, the air inlet valve and exhaust valve of the activated carbon tank B will be automatically opened, and the air inlet valve and exhaust valve of the activated carbon tank A will be automatically closed at the same time. The exhaust gas will meet the emission standards after being adsorbed by the activated carbon tank B. The steam inlet valve and exhaust valve of the activated carbon tank A are automatically opened, and the steam is used to blow off the activated carbon tank A. The gas after blowing off enters the desorption condenser, and the circulating water valve of the desorption condenser is automatically opened to cool down and condense the gas with the circulating water. The condensate produced after cooling enters the oil-water separator for stratification; After the preset time, the steam inlet valve and exhaust valve of the activated carbon tank A are automatically closed, the circulating water valve of the desorption condenser is closed, and the desorption operation is completed.

[0008] Preferably, both the activated carbon tank A and the activated carbon tank B are provided with a pressure transmitter with a high limit alarm.

[0009] The treatment process for the tail gas of the thermal oil furnace is as follows: the bagged urea is poured into the urea dissolving tank, the urea solution is pumped into the urea storage tank through the transfer pump, and the urea solution is pumped into the reactor through the spray gun through the injection pump; The flue gas from the thermal oil furnace enters from the top of the reactor tower, and the injected urea solution reacts chemically with the nitrogen oxides in the flue gas to denitrate. After being cooled by the air preheater, the low-temperature flue gas after denitrification enters the desulfurization tower through the induced draft fan; The desulfurization slurry is pumped into the desulfurization tower through the desulfurization circulation pump, so that the low-temperature flue gas and the desulfurization slurry are fully contacted and reacted in countercurrent; The sewage at the bottom of the desulfurization tower is returned to the regeneration tank and the sedimentation tank in turn. The lime nitration tank mixes powdered lime with tap water and then passes it into the regeneration tank to mix with the sewage, and then settles at the bottom of the regeneration tank and the sedimentation tank. The water at the top of the sedimentation tank flows into the circulation tank and is pumped to the desulfurization tower through the desulfurization circulation pump.

[0010] Preferably, a demister is provided at the top of the inner cavity of the desulfurization tower, and a spray layer is provided below the demister.

[0011] The beneficial effects of the present invention are: The present invention uses an organic tail gas treatment device and a thermal oil furnace tail gas treatment device to achieve classified treatment of organic tail gas generated in the production process of dinitrochlorobenzene and tail gas discharged from the thermal oil furnace flue gas after gas combustion, thereby solving the technical problem that the prior art cannot achieve standard treatment of different types of tail gas. The present invention proposes a treatment process for organic tail gas, and the desorption operation is completed by alternately adsorbing the activated carbon canister A and the activated carbon canister B. Compared with the prior art, the present invention can maintain the fluency of desorption and improve the treatment effect of the organic tail gas; The present invention proposes a treatment process for the tail gas of a thermal oil furnace. A demister is provided on the top of the inner cavity of a desulfurization tower, and a spray layer is provided below the demister. Desulfurization slurry is pumped into the spray layer of the desulfurization tower through a desulfurization circulation pump. After the low-temperature flue gas and the desulfurization slurry are countercurrently contacted and reacted fully in the spray layer, the flue gas is dehydrated by the demister and then discharged in compliance with the standards. Compared with the prior art, the present invention maintains efficient treatment of nitrile tail gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0013] Figure 1 This is a schematic diagram of the process flow of treating organic tail gas in the production process of p-dinitrochlorobenzene according to the present invention; Figure 2 This is a schematic diagram of the process flow of treating the tail gas from a thermal oil furnace in the production process of p-dinitrochlorobenzene according to the present invention; In the figure: 11. Organic tail gas condenser; 12. Dry filter; 13. Diversion fan; 14. Activated carbon tank A; 15. Activated carbon tank B; 16. Desorption condenser; 17. Oil-water separator; 21. Urea dissolution tank; 22. Urea storage tank; 23. Reactor; 24. Air preheater; 25. Induced draft fan; 26. Desulfurization tower; 27. Lime nitration tank; 28. Regeneration tank; 29. ​​Sedimentation tank; 210. Circulation tank. DETAILED DESCRIPTION

[0014] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] The present invention provides a technical solution: a dinitrochlorobenzene production waste gas treatment device, comprising an organic tail gas treatment device, a nitrate smoke tail gas treatment device, and a heat transfer oil furnace tail gas treatment device. Embodiment 1

[0016] See also Figure 1 The organic exhaust gas treatment device includes: an organic exhaust gas condenser 11 for cooling the organic exhaust gas, a dry filter 12 for filtering the exhaust gas treated by the organic exhaust gas condenser 11, a guide fan 13, an activated carbon A tank 14 and an activated carbon B tank 15 for adsorbing the exhaust treated by the dry filter 12 through the guide fan 13, a desorption condenser 16 for circulating and cooling the exhaust treated by the activated carbon A tank 14 and the activated carbon B tank 15, and an oil-water separator 17 for separating the condensed water after condensation by the desorption condenser 16.

[0017] The sources of organic tail gas are the crystallizer, dinitro transfer tank, finished product tank, mother liquor tank and chlorobenzene tank in the production process of dinitrochlorobenzene.

[0018] Based on the above-mentioned organic tail gas treatment device, the present invention also proposes a treatment process for organic tail gas, wherein the organic tail gas passes through the organic tail gas condenser 11, the dry filter 12, and the guide fan 13 in sequence and then enters the activated carbon A tank 14, and the organic matter in the tail gas is adsorbed by the activated carbon in the activated carbon A tank 14 and then meets the emission standards; After the activated carbon tank A 14 has finished adsorbing, the air inlet valve and the air exhaust valve of the activated carbon tank B 15 are automatically opened, and the air inlet valve and the air exhaust valve of the activated carbon tank A 14 are automatically closed at the same time, and the exhaust gas is adsorbed by the activated carbon tank B 15 and then discharged in compliance with the standards; The steam inlet valve and the steam exhaust valve of the activated carbon tank A 14 are automatically opened, and the steam is used to blow off the activated carbon tank A 14. The gas after blowing off enters the desorption condenser 16. The circulating water valve of the desorption condenser 16 is automatically opened, so that the circulating water cools down and condenses the gas. The condensate generated after cooling enters the oil-water separator 17 for stratification. The water in the upper layer of the oil-water separator 17 flows by gravity into the concentration first-level stratification tank (not shown in the figure), and the organic matter in the lower layer flows by gravity into the extraction kettle (not shown in the figure). After a predetermined time, the steam inlet valve and the steam exhaust valve of the activated carbon tank A 14 are automatically closed, and the circulating water valve of the desorption condenser 16 is closed, and the desorption operation is completed; It should be noted that both the activated carbon tank A 14 and the activated carbon tank B 15 are provided with a high-limit alarm pressure transmitter for alarming when exceeding the limit. Embodiment 2

[0019] See also Figure 2 The heat transfer oil furnace flue gas treatment device includes: a urea dissolving tank 21 for dissolving bagged urea, a urea storage tank 22 for storing the urea solution after stirring the urea dissolving tank 21, a reactor 23 for reacting the urea solution in the urea storage tank 22 with the introduced heat transfer oil furnace flue gas, an air preheater 24 for cooling the flue gas after denitration at the bottom of the reactor 23, an induced draft fan 25, a desulfurization tower 26 for introducing the cooled flue gas from the bottom through the induced draft fan 25, a lime nitration tank 27 for preparing lime solution, a regeneration tank 28 and a sedimentation tank 29 for mixing the sewage at the bottom of the desulfurization tower 26 with the lime solution in the lime nitration tank 27 for precipitation, and a circulation tank 210 for circulating the top water of the sedimentation tank 29 into the desulfurization tower 26.

[0020] The source of the flue gas from the thermal oil furnace is the tail gas from the combustion of coal gas during the production of dinitrochlorobenzene.

[0021] Based on the above-mentioned thermal oil furnace flue gas treatment device, the present invention also proposes a treatment process for thermal oil furnace tail gas. When the thermal oil furnace tail gas treatment device is working, bagged urea is poured into the urea dissolving tank 21, and the urea solution is pumped into the urea storage tank 22 through the transfer pump, and the urea solution is pumped into the reactor 23 through the spray gun through the injection pump; The flue gas from the thermal oil furnace enters from the top of the reactor 23, and the injected urea solution reacts chemically with the nitrogen oxides in the flue gas to denitrate. After being cooled by the air preheater 24, the low-temperature flue gas after denitration enters the desulfurization tower 26 through the induced draft fan 25; The desulfurization slurry is pumped into the desulfurization tower 26 through the desulfurization circulation pump, so that the low-temperature flue gas and the desulfurization slurry are in countercurrent contact and fully react; The sewage at the bottom of the desulfurization tower 26 is returned to the regeneration tank 28 and the sedimentation tank 29 in turn. The lime nitration tank 27 mixes the powdered lime with tap water and passes it into the regeneration tank 28 to mix with the sewage, and precipitates at the bottom of the regeneration tank 28 and the sedimentation tank 29. The water at the top of the sedimentation tank 29 flows into the circulation tank 210 and is pumped to the desulfurization tower 26 through the desulfurization circulation pump.

[0022] A demister is provided at the top of the inner cavity of the desulfurization tower 26, and a spray layer is provided below the demister. The desulfurization slurry is pumped into the spray layer of the desulfurization tower through a desulfurization circulation pump. After the low-temperature flue gas and the desulfurization slurry are fully contacted and reacted in countercurrent in the spray layer, the flue gas is dehydrated by the demister and then discharged in compliance with the emission standards.

[0023] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A waste gas treatment device for dinitrochlorobenzene production, including an organic tail gas treatment device, characterized in that: It also includes a thermal oil furnace tail gas treatment device; The organic tail gas treatment device comprises: an organic tail gas condenser (11) for cooling the organic tail gas, a dry filter (12) for filtering tail gas treated by the organic tail gas condenser (11), a guide fan (13), an activated carbon tank A (14) and an activated carbon tank B (15) for adsorbing tail gas treated by the dry filter (12) through the guide fan (13), a desorption condenser (16) for circulating and cooling the tail gas treated by the activated carbon tank A (14) and the activated carbon tank B (15), and an oil-water separator (17) for separating condensed water after condensation by the desorption condenser (16); The heat transfer oil furnace flue gas treatment device comprises: a urea dissolving tank (21) for dissolving bagged urea, a urea storage tank (22) for storing urea solution after stirring the urea dissolving tank (21), a reactor (23) for reacting the urea solution in the urea storage tank (22) with the heat transfer oil furnace flue gas introduced, an air preheater (24) for cooling the flue gas after denitration at the bottom of the reactor (23), an induced draft fan (25), a desulfurization tower (26) for introducing the cooled flue gas from the bottom through the induced draft fan (25), a lime nitration tank (27) for preparing lime solution, a regeneration tank (28) and a sedimentation tank (29) for mixing sewage at the bottom of the desulfurization tower (26) with the lime solution in the lime nitration tank (27) for precipitation, and a circulation tank (210) for circulating water at the top of the sedimentation tank (29) into the desulfurization tower (26).

2. A process for treating waste gas from the production of dinitrochlorobenzene, the organic tail gas treatment device according to claim 1, characterized in that: When the organic tail gas treatment device is in operation, the organic tail gas passes through the organic tail gas condenser (11), the dry filter (12), and the guide fan (13) in sequence before entering the activated carbon tank A (14), and organic matter in the tail gas is adsorbed by the activated carbon in the activated carbon tank A (14) before being discharged in compliance with the emission standards; After the activated carbon tank A (14) has completed adsorption, the air inlet valve and the air exhaust valve of the activated carbon tank B (15) are automatically opened, and the air inlet valve and the air exhaust valve of the activated carbon tank A (14) are automatically closed at the same time, and the exhaust gas is adsorbed by the activated carbon tank B (15) and then discharged in compliance with the emission standards; The steam inlet valve and the steam exhaust valve of the activated carbon tank A (14) are automatically opened, and the steam is used to blow off the activated carbon tank A (14). The gas after blowing off enters the desorption condenser (16). The circulating water valve of the desorption condenser (16) is automatically opened, so that the circulating water cools down and condenses the gas. The condensate generated after cooling enters the oil-water separator (17) for stratification. After a predetermined time has passed, the steam inlet valve and the steam exhaust valve of the activated carbon tank A (14) are automatically closed, and the circulating water valve of the desorption condenser (16) is closed, and the desorption operation is completed.

3. A process for treating waste gas from dinitrochlorobenzene production according to claim 2, characterized in that: The activated carbon tank A (14) and the activated carbon tank B (15) are both provided with a pressure transmitter with a high limit alarm.

4. A process for treating waste gas from dinitrochlorobenzene production according to claim 2, characterized in that: When the thermal oil furnace tail gas treatment device is in operation, bagged urea is poured into a urea dissolving tank (21), the urea solution is pumped into a urea storage tank (22) via a transfer pump, and the urea solution is pumped into a reactor (23) via a spray gun via an injection pump; The flue gas from the heat transfer oil furnace enters from the top of the reactor (23), and the injected urea solution reacts chemically with the nitrogen oxides in the flue gas to remove NOx. After being cooled by the air preheater (24), the low-temperature flue gas after denitrification enters the desulfurization tower (26) through the induced draft fan (25); The desulfurization slurry is pumped into the desulfurization tower (26) through the desulfurization circulation pump, so that the low-temperature flue gas and the desulfurization slurry are in countercurrent contact and fully react; The sewage at the bottom of the desulfurization tower (26) is returned to the regeneration tank (28) and the sedimentation tank (29) in turn. The lime nitration tank (27) mixes the powdered lime with tap water and then passes it into the regeneration tank (28) to mix with the sewage. The mixture is then precipitated at the bottom of the regeneration tank (28) and the sedimentation tank (29). The water at the top of the sedimentation tank (29) flows into the circulation tank (210) by gravity and is pumped to the desulfurization tower (26) through the desulfurization circulation pump.

5. A process for treating waste gas from dinitrochlorobenzene production according to claim 4, characterized in that: A demister is provided at the top of the inner cavity of the desulfurization tower (26), and a spray layer is provided below the demister.

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