An exhaust gas treatment system and treatment method containing dimethyl sulfoxide and decomposition products of dimethyl sulfone

Abstract

The invention discloses a waste gas treatment system containing dimethyl sulfoxide and dimethyl sulfone decomposition products, comprising a water washing system, a pickling system and an alkali washing tower which are connected in sequence through a ventilation pipeline; the water washing system comprises a first water washing tower and a second water washing tower; the pickling system comprises a plurality of pickling towers connected between the first water washing tower and the second water washing tower; the pickling system uses a pickling liquid mixed with hydrogen peroxide, sulfuric acid and nitric acid to chemically absorb waste gas; the alkali washing tower is connected to the rear of the second water washing tower; the rear of the alkali washing tower is also connected to an active alkali absorption device, and the waste gas after multi-stage washing is adsorbed by an activated carbon adsorption device and then discharged into the air.

Description

Technical Field

[0001] The present invention belongs to the technical field of air pollution treatment, and particularly relates to an exhaust gas treatment system and a treatment method for exhaust gas containing dimethyl sulfoxide and dimethyl sulfone decomposition products. Background Art

[0002] Both dimethyl sulfoxide and dimethyl sulfone are sulfur-containing organic compounds. Dimethyl sulfoxide is a colorless, odorless, transparent liquid at room temperature, with the characteristics of high polarity, high boiling point, aprotic, miscible with water, extremely low toxicity, good thermal stability, and soluble in most organic compounds such as ethanol, propanol, benzene, and chloroform, and is known as the "universal solvent". Dimethyl sulfone is a substance for the synthesis of human collagen. The main production method of dimethyl sulfone is obtained by oxidizing dimethyl sulfoxide with nitric acid, that is, dimethyl sulfoxide is oxidized with nitric acid at 140 - 145 °C. After the reaction is completed, it is cooled and filtered to obtain a crude product of white needle-like crystals, and then subjected to vacuum distillation, and the fraction collected at 138 - 145 °C (98.42 kPa) is the finished product of dimethyl sulfone.

[0003] During the use of DMSO and raw materials containing DMSO, as well as during the synthesis and use of MSM, their own decomposition will occur, decomposing into dimethyl methyl sulfide, dimethyl disulfide, methanethiol and other substances. Moreover, with the increase in temperature, the decomposition rate is faster and the decomposition amount is larger. These substances have a strong foul smell, and directly discharging them as tail gas has a certain destructive effect on the atmosphere and is not conducive to environmental protection; the tail gas containing dimethyl sulfoxide and dimethyl sulfone decomposition products also contains one or more of low-boiling organic compounds with boiling points below 90 °C such as methanol, ethanol, tetrahydrofuran, acetone, isopropanol, ethyl acetate, and methyl ethyl ketone at the same time.

[0004] In the prior art, the treatment method for tail gas containing dimethyl methyl sulfide, dimethyl disulfide, and methanethiol is to directly pass the discharged tail gas through acid washing and then oxidize it with hydrogen peroxide or sodium hypochlorite solution. However, during the acid washing and oxidation processes, the amounts of acid, hydrogen peroxide, and sodium hypochlorite used are large, the cost is high, and the treated tail gas still has an odor. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art problems, the present invention provides an exhaust gas treatment method for exhaust gas containing dimethyl sulfoxide and dimethyl sulfone decomposition products, which comprehensively treats the exhaust gas, has high treatment efficiency, can ensure that the tail gas is odorless, meets the emission requirements, and avoids air pollution.

[0006] The technical solution of the present invention is as follows:

[0007] The invention provides a waste gas treatment system containing dimethyl sulfoxide and dimethyl sulfone decomposition products, comprising a water washing system, a pickling system and an alkali washing tower which are connected in sequence through a ventilation pipeline; the water washing system comprises a first water washing tower and a second water washing tower; the pickling system comprises a plurality of pickling towers connected between the first water washing tower and the second water washing tower; the pickling system uses a pickling liquid mixed with hydrogen peroxide, sulfuric acid and nitric acid to chemically absorb the waste gas; the alkali washing tower is connected to the rear of the second water washing tower; the rear of the alkali washing tower is also connected to an activated carbon adsorption device, and the waste gas after multi-stage washing is adsorbed by the activated carbon adsorption device and then discharged into the air.

[0008] Furthermore, the pickling system is a two-stage pickling system comprising a first pickling tower and a second pickling tower; the pickling solution in the first pickling tower contains 1-20% by mass of hydrogen peroxide, 1-20% by mass of sulfuric acid and 1-10% by mass of nitric acid; the pickling solution in the second pickling tower contains 15-40% by mass of hydrogen peroxide,

[0009] 15-40% sulfuric acid and 5-20% nitric acid.

[0010] Furthermore, the alkali washing tower uses dilute alkali water with a mass fraction of 3-10% for absorption.

[0011] Furthermore, the bottom diameter of the pickling tower is 2-3 times the diameter of the cylinder.

[0012] Furthermore, a connecting pipeline is set between the outlet of the spray circulation pump of the No. 1 pickling tower and the outlet of the spray circulation pump of the No. 2 pickling tower; the pickling liquid in the No. 2 pickling tower is deployed through the connecting pipeline to replenish the No. 1 pickling tower in the form of spraying.

[0013] Furthermore, a feed system is also provided on the second pickling tower; the pickling liquid is fed in the form of circulating spraying through a pipeline connected to the spray circulation pump via a feed pump.

[0014] Furthermore, the activated carbon adsorption device is horizontally connected to the outlet pipe of the alkali washing tower; a streamlined exhaust gas passage is arranged in the activated carbon adsorption device, and the gap between the exhaust gas passage and the adsorption cylinder is filled with activated carbon adsorbent; the side wall of the exhaust gas passage is a continuous pleated structure as a whole, the side wall near the inlet of the exhaust gas passage is a gentle pleat, and the side wall near the outlet of the exhaust gas passage is an asymmetric N-shaped pleat, and the inflection points located on the side wall pleat curve and protruding toward the exhaust gas passage all cross the central axis of the adsorption cylinder.

[0015] The present invention also provides a method for treating waste gas containing dimethyl sulfoxide and dimethyl sulfone decomposition products, and the waste gas containing dimethyl sulfoxide and dimethyl sulfone decomposition products is treated by using the above-mentioned treatment system.

[0016] Further, the waste gas treatment method containing dimethyl sulfoxide and dimethyl sulfone decomposition products includes the following steps:

[0017] (1) The discharged waste gas is introduced into the first water washing tower by an induced draft fan, and the water-soluble components contained in the waste gas are removed by spray water washing.

[0018] (2) The waste gas treated by spray in the first water washing tower enters the first pickling tower, and the pickling solution containing 1-20% hydrogen peroxide, 1-20% sulfuric acid and 1-10% nitric acid by mass fraction is used to chemically absorb the waste gas.

[0019] (3) When the pH of the pickling waste liquid at the bottom of the first pickling tower is detected to be <13, 1 / 2 of the pickling waste liquid in the first pickling tower is discharged, and then the liquid supplement system is started, and the pickling solution is supplemented from the second pickling tower to the normal pickling liquid level in the first pickling tower.

[0020] (4) The waste gas passing through the first pickling tower enters the second pickling tower, and the pickling solution containing 15-40% hydrogen peroxide, 15-40% sulfuric acid and 5-20% nitric acid by mass fraction is used to chemically absorb the waste gas again; at the same time, hydrogen peroxide, sulfuric acid and nitric acid are supplemented through the feeding system of the second pickling tower respectively.

[0021] (5) The waste gas after chemical absorption in the second pickling tower is purified in the second water washing tower to remove the water-soluble substances generated after pickling and not completely absorbed and the acid gas brought out from the pickling system.

[0022] (6) The waste gas after secondary water washing enters the alkali washing tower, and the residual acidic substances are absorbed by the dilute alkali water with a mass fraction of 3-10%.

[0023] (7) Finally, the waste gas enters the activated carbon tail gas adsorption device for tail gas adsorption and is discharged at high altitude.

[0024] Further, in step (4), when supplementing hydrogen peroxide, sulfuric acid and nitric acid in the second pickling tower, nitric acid and sulfuric acid are preferably added slowly through an external pipeline, and after the slow heat release ends, hydrogen peroxide is added through the external pipeline, so as to prevent the decomposition of hydrogen peroxide under the heated state.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. The present invention provides an exhaust gas treatment system and method containing dimethyl sulfoxide and dimethyl sulfone decomposition products, which specifically disposes of various components in the tail gas in sequence. The exhaust gas is first washed with water to remove most of the impurities that are easily soluble in water, reducing the amount of subsequent acid cleaning solution used. The subsequent acid cleaning uses a mixed solution of hydrogen peroxide, sulfuric acid, and nitric acid. Both nitric acid and sulfuric acid have oxidizing properties, and their combined oxidizing property is enhanced, which is more conducive to the reaction absorption of the tail gas. Concentrated sulfuric acid is injected in the form of supplementary liquid spraying into the pipeline to be evenly mixed, and slowly flows down onto the packing of the spraying tower, reducing the risk caused by the use of concentrated sulfuric acid. When mixed and entering the spraying tower, a concentration gradient is formed after natural absorption from top to bottom for a period of time. The front tower first contacts the tail gas, with a high reaction concentration and rapid acid consumption. The rear tower contacts the tail gas with a much lower concentration, and the acid consumption is slow, forming a primary concentration and a secondary concentration. The addition of hydrogen peroxide in the acid cleaning materials plays an oxidizing role on the one hand to oxidize the components in the exhaust gas into substances that are easily soluble, and on the other hand, improves the oxidizing property of the acid.

[0027] 2. In the present invention, pre-washing with water can remove water-soluble organic substances in advance, reduce the amount of organic substances entering the subsequent acid cleaning tower, and save the amount of acid used.

[0028] 3. In the present invention, a supplementary liquid system is arranged between the first acid cleaning tower and the second acid cleaning tower in the acid cleaning system, which fully utilizes the acid cleaning solution in the second acid cleaning tower to adjust the acid cleaning efficiency and the concentration of the mixed acid in the first acid cleaning tower, reducing the acid cleaning cost. At the same time, the supplementary liquid is carried out in the form of spraying to prevent the sudden boiling phenomenon caused by the change of acid liquid concentration and heat release or the decomposition and invalidation of hydrogen peroxide caused by too rapid temperature rise.

[0029] 4. In the present invention, the bottom diameter of the acid cleaning tower is 2 - 3 times the diameter of the cylinder body, reducing the gas flow rate after the tail gas enters the spraying tower, increasing the residence time of the gas in the spraying tower to enhance the reaction absorption effect.

[0030] 5. In the present invention, the activated carbon adsorption device is specially designed. By setting wrinkles on the inner wall of the activated carbon adsorption device, at the same time, the wrinkles also present different shape transitions. The wrinkles at the inlet are set to be gentle. Under the action of the induced draft fan, when the tail gas enters the activated carbon adsorption device, the gentle wrinkles can reduce the rate of the tail gas entering the activated carbon adsorption device, enabling full absorption by the filled activated carbon when the impurity concentration in the tail gas is relatively high. Near the outlet of the activated carbon adsorption device, the change of the wrinkles is used to change the adsorption efficiency, increasing the contact area between the tail gas and the activated carbon packing, achieving multiple adsorption and improving the adsorption efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the exhaust gas treatment system in Embodiment 1 of the present invention;

[0032] Figure 2 It is a sectional view of the activated carbon adsorption device in the present invention. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings.

[0034] Example 1

[0035] join Figures 1 to 2 A waste gas treatment system containing dimethyl sulfoxide and dimethyl sulfone decomposition products, comprising a water washing system, an acid washing system and an alkali washing tower connected in sequence through a ventilation pipe; the water washing system comprises a first water washing tower and a second water washing tower; the acid washing system comprises a plurality of stages of acid washing towers connected between the first water washing tower and the second water washing tower; the acid washing system uses an acid washing liquid mixed with hydrogen peroxide, sulfuric acid and nitric acid to chemically absorb the waste gas; the alkali washing tower is connected to the rear of the second water washing tower; the rear of the alkali washing tower is also connected to an activated carbon adsorption device, and the waste gas after multi-stage washing is adsorbed by the activated carbon adsorption device and then discharged into the air.

[0036] In this embodiment, the pickling system is a two-stage pickling system including a No. 1 pickling tower and a No. 2 pickling tower; the pickling liquid in the No. 1 pickling tower contains 1-20% by mass of hydrogen peroxide, 1-20% by mass of sulfuric acid and 1-10% by mass of nitric acid; the pickling liquid in the No. 2 pickling tower contains 15-40% by mass of hydrogen peroxide, 15-40% by mass of sulfuric acid and 5-20% by mass of nitric acid; and the alkali washing tower uses dilute alkali water with a mass fraction of 3-10% for absorption.

[0037] In this embodiment, the bottom diameter of the pickling tower is 2-3 times the diameter of the cylinder, which reduces the gas flow rate after the tail gas enters the spray tower and increases the residence time of the gas in the spray tower to increase the reaction absorption effect.

[0038] In this embodiment, a connecting pipeline is set between the outlet of the spray circulation pump of the No. 1 pickling tower and the outlet of the spray circulation pump of the No. 2 pickling tower; the pickling liquid in the No. 2 pickling tower is deployed through the connecting pipeline to replenish the No. 1 pickling tower in the form of spraying, and the pickling liquid in the No. 2 pickling tower is fully utilized to adjust the pickling efficiency and mixed acid concentration of the No. 1 pickling tower, thereby reducing the pickling cost. At the same time, the replenishment is carried out in the form of spraying to prevent the sudden boiling phenomenon caused by the heat release of the acid concentration change or the temperature rising too fast to cause the decomposition and failure of hydrogen peroxide.

[0039] The No. 2 pickling tower is also provided with a feeding system; the pickling liquid is fed in the form of circulating spraying through a pipeline connected to the spray circulation pump via a feeding pump.

[0040] like Figure 2As shown in the figure, in this embodiment, the activated carbon adsorption device is horizontally connected to the exhaust gas pipeline of the alkali washing tower; a streamlined exhaust gas passage is arranged inside the activated carbon adsorption device, and activated carbon adsorbents are filled in the gap between the exhaust gas passage and the adsorption cylinder; the side wall of the exhaust gas passage is integrally in a continuous corrugated structure, the side wall near the inlet of the exhaust gas passage is a gentle corrugation, and the side wall near the outlet of the exhaust gas passage is an asymmetric N-shaped corrugation. All the inflection points located on the corrugation curve of the side wall and protruding towards the exhaust gas passage cross the central axis of the adsorption cylinder.

[0041] Example 2

[0042] A method for treating exhaust gas containing dimethyl sulfoxide and dimethyl sulfone decomposition products includes the following steps:

[0043] (1) Introduce the discharged exhaust gas into the first water washing tower through a draft fan, and remove the water-soluble components contained in the exhaust gas through spray water washing.

[0044] (2) The exhaust gas after being treated by spray in the first water washing tower enters the first acid washing tower, and the acid washing liquid containing 1-20% hydrogen peroxide, 1-20% sulfuric acid and 1-10% nitric acid by mass fraction is used to chemically absorb the exhaust gas.

[0045] (3) When it is detected that the pH of the acid washing waste liquid at the bottom of the first acid washing tower is < 13, discharge 1 / 2 of the acid washing waste liquid in the first acid washing tower, and then start the liquid supplementing system to supplement the acid washing liquid from the second acid washing tower to the normal acid washing liquid level in the first acid washing tower.

[0046] (4) The exhaust gas passing through the first acid washing tower enters the second acid washing tower, and the acid washing liquid containing 15-40% hydrogen peroxide, 15-40% sulfuric acid and 5-20% nitric acid by mass fraction is used to chemically absorb the exhaust gas again; at the same time, hydrogen peroxide, sulfuric acid and nitric acid are respectively supplemented through the feeding system of the second acid washing tower. When supplementing hydrogen peroxide, sulfuric acid and nitric acid, nitric acid and sulfuric acid are preferably slowly added through an external pipeline first, and after the slow heat release ends, hydrogen peroxide is added through the external pipeline, so as to prevent the decomposition of hydrogen peroxide under the heated state.

[0047] (5) The exhaust gas after chemical absorption in the second acid washing tower is purified in the second water washing tower to remove the water-soluble substances generated after acid washing and not completely absorbed and the acid gas brought out from the acid washing system.

[0048] (6) The exhaust gas after secondary water washing enters the alkali washing tower, and the residual acidic substances are absorbed by the dilute alkali water with a mass fraction of 3-10%.

[0049] (7) Finally, the exhaust gas enters the activated carbon tail gas adsorption device for tail gas adsorption and then is discharged into the air at a high altitude.

[0050] The above are only specific embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. An exhaust gas treatment system containing dimethyl sulfoxide and decomposition products of dimethyl sulfone, characterized in that, It includes a water washing system, an acid washing system, and an alkali washing tower that are connected in sequence through a ventilation pipeline; the water washing system includes a first water washing tower and a second water washing tower; the acid washing system includes several stages of acid washing towers connected between the first water washing tower and the second water washing tower; the acid washing system uses an acid washing solution mixed with hydrogen peroxide, sulfuric acid, and nitric acid to chemically absorb the waste gas; the alkali washing tower is connected behind the second water washing tower; an activated carbon adsorption device is also connected behind the alkali washing tower, and the waste gas after multi-stage washing is adsorbed by the activated carbon adsorption device and then discharged into the air at a high altitude; the acid washing system is a two-stage acid washing system including a first acid washing tower and a second acid washing tower; the acid washing solution in the first acid washing tower contains 1-20% by mass of hydrogen peroxide, 1-20% by mass of sulfuric acid, and 1-10% by mass of nitric acid; the acid washing solution in the second acid washing tower contains 15-40% by mass of hydrogen peroxide, 15-40% by mass of sulfuric acid, and 5-20% by mass of nitric acid.

2. The waste gas treatment system containing dimethyl sulfoxide and decomposition products of dimethyl sulfone as described in claim 1, characterized in that, In the alkali washing tower, dilute alkali water with a mass fraction of 3-10% is used for absorption.

3. The waste gas treatment system containing decomposition products of dimethyl sulfoxide and dimethyl sulfone according to claim 2, characterized in that, The bottom diameter of the acid washing tower is 2-3 times the diameter of the cylinder body.

4. An exhaust gas treatment system containing dimethyl sulfoxide and dimethyl sulfone decomposition products as described in claim 3, characterized in that, A connecting pipeline is arranged between the outlet of the spray circulation pump of the first acid washing tower and the outlet of the spray circulation pump of the second acid washing tower; the acid washing solution in the second acid washing tower is adjusted through the connecting pipeline to supplement the first acid washing tower in a spray form.

5. An exhaust gas treatment system containing dimethyl sulfoxide and decomposition products of dimethyl sulfone as described in claim 4, characterized in that, A feeding system is also arranged on the second acid washing tower; it is connected to the pipeline of the spray circulation pump through a feeding pump, and the acid washing solution is fed in a circulating spray form.

6. The waste gas treatment system containing dimethyl sulfoxide and dimethyl sulfone decomposition products as described in claim 5, characterized in that, The activated carbon adsorption device is horizontally connected to the air outlet pipeline of the alkali washing tower; a streamlined waste gas passage is arranged in the activated carbon adsorption device, and activated carbon adsorbent is filled in the gap between the waste gas passage and the adsorption cylinder; the side wall of the waste gas passage is integrally in a continuous fold structure, the side wall near the inlet of the waste gas passage is a gentle fold, the side wall near the outlet of the waste gas passage is an asymmetric N-shaped fold, and all the inflection points located on the side wall fold curve and protruding towards the waste gas passage cross the central axis of the adsorption cylinder.

7. An exhaust gas treatment method containing dimethyl sulfoxide and decomposition products of dimethyl sulfone, characterized in that: Use the treatment system as described in any one of claims 1 to 6 to treat the waste gas containing dimethyl sulfoxide and dimethyl sulfone decomposition products.

8. The waste gas treatment method containing dimethyl sulfoxide and decomposition products of dimethyl sulfone according to claim 7, characterized in that, It includes the following steps: (1) Introduce the discharged waste gas into the first water washing tower through a draft fan, and remove the components soluble in water contained in the waste gas through spray water washing. (2) The waste gas after being spray-treated by the first water washing tower enters the first acid washing tower, and the acid washing solution containing 1-20% by mass of hydrogen peroxide, 1-20% by mass of sulfuric acid, and 1-10% by mass of nitric acid chemically absorbs the waste gas. (3) When it is detected that the pH of the acid washing waste liquid at the bottom of the first acid washing tower is <13, discharge 1 / 2 of the acid washing waste liquid in the first acid washing tower and then start the liquid supplementing system to supplement the acid washing solution from the second acid washing tower to the normal acid washing liquid level in the first acid washing tower. (4) The waste gas passing through the first acid washing tower enters the second acid washing tower, and the acid washing solution containing 15-40% by mass of hydrogen peroxide, 15-40% by mass of sulfuric acid, and 5-20% by mass of nitric acid chemically absorbs the waste gas again; at the same time, hydrogen peroxide, sulfuric acid, and nitric acid are supplemented through the feeding system of the second acid washing tower. (5) The waste gas after chemical absorption in the second pickling tower is purified in the second water washing tower to remove the water-soluble substances generated after pickling and not completely absorbed, as well as the acid gas carried out from the pickling system. (6) The waste gas after secondary water washing enters the alkali washing tower, and the residual acidic substances are absorbed by dilute alkali water with a mass fraction of 3-10%. (7) Finally, the waste gas enters the activated carbon tail gas adsorption device for tail gas adsorption and is discharged at high altitude.

9. The waste gas treatment method containing dimethyl sulfoxide and dimethyl sulfone decomposition products as described in claim 8, characterized in that: In step (4), when adding hydrogen peroxide, sulfuric acid, and nitric acid to the second pickling tower, nitric acid and sulfuric acid are preferably added slowly through an external pipeline, and then hydrogen peroxide is added through the external pipeline after the slow heat release ends, thereby preventing the decomposition of hydrogen peroxide under the heated state.

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