Isothiazolinone production tail gas treatment device

Abstract

The utility model discloses an isothiazolinone production tail gas treatment device, which relates to the technical field of tail gas treatment and comprises a buffer tank, a pre-washing tower, an alkaline washing tower, an activated carbon adsorption tower, an induced draft fan and a chimney, the top of the pre-washing tower and the top of the alkaline washing tower are provided with a first spraying mechanism and a second spraying mechanism respectively, the first spraying mechanism and the second spraying mechanism are the same in structure and each comprise a spraying pipe and a multi-stage flow dividing pipe communicated with the spraying pipe, the multi-stage flow dividing pipes are each provided with a spraying head, and a perforated plate is arranged between every two adjacent flow dividing pipes; air flow distribution mechanisms are arranged at air inlets of the prewashing tower, the alkaline washing tower and the activated carbon adsorption tower. The device not only can effectively absorb harmful gas in the tail gas, but also can reduce the tail gas treatment energy consumption.

Description

Technical Field

[0001] This utility model relates to the field of exhaust gas treatment technology, specifically to an exhaust gas treatment device for isothiazolinone production. Background Technology

[0002] Isothiazolinones are mainly composed of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one. Isothiazolinones exhibit strong inhibitory and bactericidal effects against common bacteria, fungi, and algae, with high biocidal efficiency, good degradation properties, and characteristics such as no residue, safe operation, good compatibility, strong stability, and low cost. They are miscible with chlorine and most anionic, cationic, and nonionic surfactants. Therefore, they are widely used in industries such as oil fields, papermaking, pesticides, cutting oils, leather, inks, dyes, and tanning.

[0003] The main production route for isothiazolinones is as follows: First, methyl acrylate reacts with sodium polysulfide to produce dimethyl dithiodipropionate; then, dimethyl dithiodipropionate condenses with an amine to produce dithiodipropionamide; finally, ring closure is achieved in halogenating agents and solvents such as chlorine and sulfuryl chloride to generate isothiazolinones. This route offers high product yields, but it generates certain exhaust gases, which, if not treated promptly, will pollute the atmosphere. Therefore, providing an effective exhaust gas treatment device is of great significance for the production of isothiazolinones. Summary of the Invention

[0004] The technical problem to be solved by this utility model is to provide an isothiazolinone production tail gas treatment device to address the shortcomings of the existing technology. This device can not only effectively absorb harmful gases in the tail gas, but also reduce the energy consumption of tail gas treatment.

[0005] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0006] A tail gas treatment device for isothiazolinone production includes a buffer tank, a pre-washing tower, an alkaline washing tower, an activated carbon adsorption tower, an induced draft fan, and a chimney. The top of the pre-washing tower is equipped with a first spraying mechanism, and the top of the alkaline washing tower is equipped with a second spraying mechanism. The first and second spraying mechanisms have the same structure, each including a spray pipe and a multi-stage distribution pipe connected to the spray pipe. Each multi-stage distribution pipe is equipped with a nozzle, and a perforated plate is provided between adjacent distribution pipes, with the holes on the adjacent perforated plates arranged alternately. An airflow distribution mechanism is provided at the air inlet of the pre-washing tower, the alkaline washing tower, and the activated carbon adsorption tower. The airflow distribution mechanism includes an inlet pipe and a distribution plate connected to the inlet pipe. The side wall of the distribution plate is provided with multiple air outlets, and a spiral blade is movably installed inside the inner cavity of the distribution plate.

[0007] Preferably, the exhaust pipe of the buffer tank is equipped with a gas flow regulating valve.

[0008] Preferably, the bottom of the pre-washing tower is provided with a first washing liquid storage tank, which is connected to a multi-stage diversion pipe through a first circulation pipe. The first circulation pipe is provided with a first circulation pump and a first circulation valve. The first washing liquid storage tank is connected to an acid absorption tank through a first drain pipe, which is provided with a first drain valve.

[0009] Preferably, the first washing liquid storage tank is equipped with a first pH sensor, which is interlocked with the first circulation pump, the first circulation valve, and the first drain valve.

[0010] Preferably, the bottom of the alkaline washing tower is provided with a second washing liquid storage tank, the second washing liquid storage tank is connected to a multi-stage diversion pipe through a second circulation pipe, and the second circulation pipe is provided with a second circulation pump and a second circulation valve; the second washing liquid storage tank is connected to an alkaline absorption tank through a second drain pipe, and the second drain pipe is provided with a second drain valve.

[0011] Preferably, the second washing liquid storage tank is equipped with a second pH sensor, which is interlocked with the second circulation valve, the second circulation pump, and the second drain valve.

[0012] Preferably, the air outlet at the top of the pre-washing tower and the alkali washing tower is provided with a conical liquid baffle.

[0013] Preferably, a VOC detector is provided at the outlet of the activated carbon adsorption tower. The outlet of the activated carbon adsorption tower is connected to the pre-washing tower and the chimney through a first gas pipeline and a first electric valve, a second gas pipeline and a second electric valve, respectively. The VOC detector is interlocked with the first electric valve and the second electric valve.

[0014] Preferably, the top of the air distribution plate is arc-shaped.

[0015] Due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0016] This invention provides a tail gas treatment device for isothiazolinone production, including a buffer tank, a pre-washing tower, an alkaline washing tower, an activated carbon adsorption tower, an induced draft fan, and a chimney. The tail gas produced in the production process is sequentially treated by water absorption in the pre-washing tower, by alkaline absorption in the alkaline washing tower, and by adsorption in the activated carbon adsorption tower. The treated tail gas is then discharged into the atmosphere through the chimney by the induced draft fan, preventing the tail gas from being directly emitted and polluting the atmosphere.

[0017] The pre-washing tower in this device is equipped with a first spraying mechanism at its top, and the alkaline washing tower is equipped with a second spraying mechanism at its top. The first and second spraying mechanisms have identical structures, both including spray pipes and multi-stage distribution pipes connected to the spray pipes. Each multi-stage distribution pipe is equipped with a nozzle. During its ascent, the gas comes into contact with the liquid sprayed through the multi-stage distribution pipes and from the nozzles on the multi-stage distribution pipes, thereby improving gas absorption efficiency. Perforated plates are placed between adjacent distribution pipes, with the holes on the perforated plates staggered to further disperse and homogenize the sprayed liquid.

[0018] The pre-washing tower, alkaline washing tower, and activated carbon adsorption tower of this device are all equipped with airflow distribution mechanisms at their inlets. These mechanisms include inlet pipes and distribution discs connected to the inlet pipes. The sidewalls of the distribution discs have multiple outlet holes, and spiral blades are movably mounted within the disc's inner cavity. The airflow distribution mechanisms ensure that waste gas can enter each tower evenly, improving waste gas treatment efficiency.

[0019] The pre-washing tower of this device has a first washing liquid storage tank at its bottom, which is connected to a multi-stage distribution pipe via a first circulation pipe. The first circulation pipe is equipped with a first circulation pump and a first circulation valve. The first washing liquid storage tank is connected to an acid absorption tank via a first drain pipe, which is equipped with a first drain valve. A first pH sensor is installed inside the first washing liquid storage tank, and the first pH sensor is interlocked with the first circulation pump, the first circulation valve, and the first drain valve. The alkaline washing tower has a second washing liquid storage tank at its bottom, which is connected to a multi-stage distribution pipe via a second circulation pipe. The second circulation pipe is equipped with a second circulation pump and a second circulation valve. The second washing liquid storage tank is connected to an alkaline absorption tank via a second drain pipe, which is equipped with a second drain valve. A second pH sensor is installed inside the second washing liquid storage tank, and the second pH sensor is interlocked with the second circulation valve, the second circulation pump, and the second drain valve. This setup allows for the recycling of the washing liquid by monitoring its concentration, thereby reducing energy consumption.

[0020] The alkaline scrubbing tower of this unit is equipped with a conical liquid baffle at the gas outlet. The inclined surface of the conical liquid baffle can guide the liquid droplets entrained in the gas flow to collide and gather and flow back into the tower, thereby significantly reducing the liquid loss after gas-liquid separation. Moreover, the conical design of the liquid baffle can optimize the airflow distribution, reduce local turbulence, and enhance the capture efficiency of small liquid droplets.

[0021] The activated carbon adsorption tower of this device is equipped with a VOC detector at its outlet. The outlet of the activated carbon adsorption tower is connected to the pre-washing tower and the chimney through a first gas pipeline and a first electric valve, a second gas pipeline and a second electric valve, respectively. The VOC detector is interlocked with the first electric valve and the second electric valve, respectively. The above settings can further improve the exhaust gas treatment efficiency. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of this utility model;

[0024] Figure 2 yes Figure 1 Enlarged structural diagram at point A;

[0025] Figure 3 This is a schematic diagram of the structure of the air distribution plate in Embodiment 1 of this utility model;

[0026] In the diagram, 1. Buffer tank; 2. Pre-washing tower; 3. Alkali washing tower; 4. Activated carbon adsorption tower; 5. Exhaust fan; 6. Chimney; 7. Spray pipe; 8. Multi-stage diversion pipe; 9. Spray nozzle; 10. Perforated plate; 11. Inlet pipe; 12. Gas distribution plate; 13. Outlet; 14. Spiral blade; 15. Gas flow regulating valve; 16. First washing liquid storage tank; 17. First circulation pipeline; 18. First circulation pump; 19. First circulation valve; 20. Acid adsorption... 21. Receiving tank; 22. First drain valve; 23. First pH sensor; 24. Second washing liquid storage tank; 25. Second circulation pipeline; 26. Second circulation pump; 27. Second circulation valve; 28. Alkali absorption tank; 29. ​​Second drain valve; 30. Second pH sensor; 31. Conical liquid baffle; 32. VOC detector; 33. First gas pipeline; 34. First electric valve; 35. Second gas pipeline; 36. Second electric valve. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0028] Example 1

[0029] Reference Figure 1-3 As shown in the figure, an isothiazolinone production tail gas treatment device includes a buffer tank 1, a pre-washing tower 2, an alkaline washing tower 3, an activated carbon adsorption tower 4, an induced draft fan 5, and a chimney 6.

[0030] like Figure 1 and 2As shown, the top of the pre-washing tower 2 is equipped with a first spraying mechanism, and the top of the alkaline washing tower 3 is equipped with a second spraying mechanism. The first and second spraying mechanisms have the same structure, both including a spray pipe 7 and a multi-stage diversion pipe 8 connected to the spray pipe 7. Each multi-stage diversion pipe 8 is equipped with a nozzle 9, and a perforated plate 10 is provided between adjacent diversion pipes, with the holes on adjacent perforated plates 10 arranged alternately. The tail gas first enters the pre-washing tower 2 through a buffer tank and is washed with water to remove hydrogen chloride gas from the tail gas. Then it enters the alkaline washing tower 3 for re-absorption to remove chlorine gas and incompletely absorbed hydrogen chloride gas from the tail gas. The combined arrangement of the spray pipe 7, the multi-stage diversion pipe 8, and the nozzle 9 ensures that the liquid is evenly distributed in the tower, improving the spraying efficiency. The perforated plate 10 further ensures the even distribution of the liquid and avoids local blockage or over-spraying.

[0031] like Figure 1 and Figure 3 As shown, the pre-washing tower 2, the alkaline washing tower 3, and the activated carbon adsorption tower 4 are all equipped with airflow distribution mechanisms at their inlets. Each airflow distribution mechanism includes an inlet pipe 11 and a distribution plate 12 connected to the inlet pipe 11. The sidewall of the distribution plate 12 has multiple outlet holes 13, and a spiral blade 14 is movably mounted inside the inner cavity of the distribution plate 12. After the exhaust gas enters the distribution plate 12 through the inlet pipe 11, the gas impacts the spiral blade 14, causing it to rotate with the airflow. This creates a spiral flow path within the distribution plate 12, thereby increasing the residence time of the gas and improving the uniformity of gas distribution.

[0032] like Figure 1 As shown, in this embodiment, the gas flow regulating valve 15 is provided on the exhaust pipe of the buffer tank 1. By adjusting the opening of the gas flow regulating valve 15, the gas emission rate can be precisely controlled to prevent rapid gas emission from causing impact or damage to the system.

[0033] like Figure 1As shown, the bottom of the pre-washing tower 2 is provided with a first washing liquid storage tank 16. The first washing liquid storage tank 16 is connected to the multi-stage diversion pipe 8 through a first circulation pipe 17. The first circulation pipe 17 is provided with a first circulation pump 18 and a first circulation valve 19. The first washing liquid storage tank 16 is connected to an acid absorption tank 20 through a first drain pipe (not shown in the figure). The first drain pipe is provided with a first drain valve 21. The first washing liquid storage tank 16 is provided with a first pH sensor 22. The first pH sensor 22 is interlocked with the first circulation pump 18, the first circulation valve 19, and the first drain valve 21. By activating the first circulation pump 18, the washing liquid in the first washing liquid storage tank 16 is reused for the absorption and treatment of exhaust gas, reducing water consumption and thus energy consumption. When the first pH sensor 22 detects that the pH value of the washing liquid is lower than the set value (indicating that the acid content in the washing liquid is too high), the system will automatically close the first circulation valve 19 and the first circulation pump 18, stop the delivery of washing liquid to the multi-stage diversion pipe 8, prevent the acidic waste liquid from being recycled, open the first drain valve 21 to drain the washing liquid in the first washing liquid storage tank 16, and add water to the pre-washing tower 2 for absorption and treatment. When the first pH sensor 22 detects that the pH value of the washing liquid has returned to the set range, the system will automatically close the first drain valve 21 and open the first circulation valve 19 to restart the washing liquid circulation.

[0034] like Figure 1 As shown, the bottom of the alkaline washing tower 3 is provided with a second washing liquid storage tank 23. The second washing liquid storage tank 23 is connected to the multi-stage diversion pipe 8 through a second circulation pipe 24. The second circulation pipe 24 is provided with a second circulation pump 25 and a second circulation valve 26. The second washing liquid storage tank 23 is connected to an alkaline absorption tank 27 through a second drain pipe (not shown in the figure). The second drain pipe is provided with a second drain valve 28. The second washing liquid storage tank 23 is provided with a second pH sensor 29. The second pH sensor 29 is interlocked with the second circulation valve 26, the second circulation pump 25, and the second drain valve 28. When the second pH sensor 29 detects that the pH value of the washing liquid is lower than the set range (indicating insufficient alkalinity), the system will automatically close the second circulation valve 26, stop supplying washing liquid to the multi-stage distribution pipe 8, and open the second drain valve 28 to discharge the waste liquid into the alkaline absorption tank 27. New alkaline solution will be added to the alkaline washing tower 3 for absorption treatment. When the second pH sensor 29 detects that the pH value of the washing liquid has returned to the set range, the system will automatically close the second drain valve 28 and open the second circulation valve 26 to restart the washing liquid circulation.

[0035] Furthermore, in this embodiment, the outlets at the top of the pre-washing tower 2 and the alkaline washing tower 3 are equipped with conical liquid baffles 30, which can not only guide the direction of the exhaust gas flow and reduce the turbulence and vortex in the airflow inside the tower, ensuring that the exhaust gas can be discharged smoothly through the outlet; but also, during the rise of the exhaust gas, the conical liquid baffles 30 can effectively reduce the entrainment of liquid droplets, thereby achieving liquid-gas separation.

[0036] Furthermore, in this embodiment, a VOC detector 31 is installed at the outlet of the activated carbon adsorption tower 4. The outlet of the activated carbon adsorption tower 4 is connected to the pre-washing tower 2 and the chimney 6 through a first gas pipeline 32 and a first electric valve 33, a second gas pipeline 34 and a second electric valve 35, respectively. The VOC detector 31 is interlocked with the first electric valve 33 and the second electric valve 35. The VOC detector 31 continuously monitors the VOC concentration in the waste gas after treatment by the activated carbon adsorption tower. When the VOC concentration exceeds the standard, the system will automatically close the second electric valve 35 to cut off the gas passage to the chimney 6 and open the first electric valve 33 to guide the waste gas back to the pre-washing tower 2 for further treatment. When the VOC concentration drops to within the standard range, the system will automatically open the second electric valve 35 to discharge the purified waste gas into the atmosphere through the chimney 6.

[0037] Furthermore, it should be understood that after reading the teachings of this utility model, those skilled in the art can make various alterations or modifications to this utility model, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A tail gas treatment device for isothiazolinone production, characterized in that: The system includes a buffer tank, a pre-washing tower, an alkaline washing tower, an activated carbon adsorption tower, an induced draft fan, and a chimney. The top of the pre-washing tower is equipped with a first spraying mechanism, and the top of the alkaline washing tower is equipped with a second spraying mechanism. The first and second spraying mechanisms have identical structures, each including a spray pipe and a multi-stage distribution pipe connected to the spray pipe. Each multi-stage distribution pipe is equipped with a nozzle, and a perforated plate is installed between adjacent distribution pipes, with the holes on the adjacent perforated plates arranged alternately. An airflow distribution mechanism is installed at the air inlet of each of the pre-washing tower, alkaline washing tower, and activated carbon adsorption tower. The airflow distribution mechanism includes an air inlet pipe and a distribution plate connected to the air inlet pipe. The side wall of the distribution plate has multiple air outlets, and spiral blades are movably installed within the inner cavity of the distribution plate.

2. The isothiazolinone production tail gas treatment device according to claim 1, characterized in that: The buffer tank is equipped with a gas flow regulating valve on its exhaust pipe.

3. The isothiazolinone production tail gas treatment device according to claim 1, characterized in that: The pre-washing tower is provided with a first washing liquid storage tank at the bottom. The first washing liquid storage tank is connected to a multi-stage diversion pipe through a first circulation pipe. The first circulation pipe is provided with a first circulation pump and a first circulation valve. The first washing liquid storage tank is connected to an acid absorption tank through a first drain pipe. The first drain pipe is provided with a first drain valve.

4. The isothiazolinone production tail gas treatment device according to claim 3, characterized in that: The first washing liquid storage tank is equipped with a first pH sensor, which is interlocked with the first circulation pump, the first circulation valve, and the first drain valve.

5. The isothiazolinone production tail gas treatment device according to claim 1, characterized in that: The bottom of the alkaline washing tower is provided with a second washing liquid storage tank, which is connected to a multi-stage diversion pipe through a second circulation pipe. The second circulation pipe is equipped with a second circulation pump and a second circulation valve. The second washing liquid storage tank is connected to an alkaline absorption tank through a second drain pipe, which is equipped with a second drain valve.

6. The isothiazolinone production tail gas treatment device according to claim 5, characterized in that: The second washing liquid storage tank is equipped with a second pH sensor, which is interlocked with the second circulation valve, the second circulation pump, and the second drain valve.

7. The isothiazolinone production tail gas treatment device according to claim 1, characterized in that: The pre-washing tower and the alkaline washing tower are equipped with conical liquid baffles at the air outlets at the top.

8. The isothiazolinone production tail gas treatment device according to claim 1, characterized in that: A VOC detector is installed at the outlet of the activated carbon adsorption tower. The outlet of the activated carbon adsorption tower is connected to the pre-washing tower and the chimney through a first gas pipeline and a first electric valve, a second gas pipeline and a second electric valve, respectively. The VOC detector is interlocked with the first electric valve and the second electric valve.

9. The isothiazolinone production tail gas treatment device according to claim 1, characterized in that: The top of the air distribution plate is arc-shaped.

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