Sulfur-containing tail gas cleaning treatment device and sulfur-containing tail gas treatment method

Abstract

The invention discloses a sulfur-containing tail gas cleaning treatment device and a sulfur-containing tail gas treatment method. The sulfur-containing tail gas cleaning treatment device comprises a tail gas washing tower, an acid removal tower, a blow-down pipe and a circulating liquid cooler, a gas outlet of the tail gas washing tower is connected with the deacidification tower, a gas outlet of the deacidification tower is connected with the blow-down pipe, and a liquid outlet of the deacidification tower is connected with the circulating liquid cooler; the tail gas washing tower and the circulating liquid cooler form a circulating path for cooling acid liquid discharged from the lower end of the tail gas washing tower; the tail gas washing tower is connected with a hydrogen peroxide input channel for introducing hydrogen peroxide; the deacidification tower is connected with a desalted water input channel and is used for introducing desalted water; the device is simple in structure, sulfur-containing tail gas is treated, SO2 in the final tail gas is smaller than or equal to 35 mg / Nm < 3 >, the acid mist content is smaller than or equal to 5 mg / Nm < 3 >, peculiar smells and harmful substances in the environment are eliminated, sulfur in the tail gas forms sulfuric acid, the sulfuric acid is discharged outwards for a circulating water station to adjust the pH value, hydrogen peroxide serves as a removing agent, water is formed after reaction, other components are not added, and the purpose of clean production is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of sulfur-containing tail gas treatment, and in particular relates to a sulfur-containing tail gas cleaning treatment device and a sulfur-containing tail gas treatment method. Background Art

[0002] Industrial waste gas containing one or two of hydrogen sulfide, sulfur dioxide, and elemental sulfur has a peculiar smell and affects the environmental quality. For example, sulfur dioxide, as the main environmental pollutant, is the main cause of acid rain, which destroys plant growth and has a strong irritating effect on human respiratory tract. Usually, the incineration process is adopted, but for insufficient calorific value, it is necessary to use fuel to increase the calorific value and then mix it, which wastes energy. Patent CN107469602A discloses a technology for recovering sulfur-containing tail gas to meet emission standards. The device for recovering sulfur-containing tail gas includes a condensing medium inlet, a process gas inlet, an acid condenser, a quenching tower, a dilute sulfuric acid quenching solution inlet, a water injection point 1, a quenching pump, a hydrogen peroxide washing tower, a washing tower bottom pump, a water injection point 2, a hydrogen peroxide solution inlet, an electrostatic demister, a quenching liquid pump and a standard gas outlet. The quenching tower, the hydrogen peroxide washing tower, and the electrostatic demister are used to absorb the sulfur-containing substances in the process gas, and the washing liquid is recycled in the device. The method for treating sulfur-containing tail gas using this method is complicated. The sulfur dioxide in the sulfur-containing tail gas is mainly absorbed by the dilute sulfuric acid quenching solution, a small amount of sulfur dioxide and most of the hydrogen sulfide react with hydrogen peroxide, and then the acid mist in the remaining gas is processed by the electrostatic demister, and the gas is discharged after meeting the standards. This method focuses on the treatment of tail gas, but it is difficult to use it directly after treatment, which increases the treatment cost. Summary of the invention

[0003] In view of the problems of complex and high cost in the prior art for treating sulfur-containing tail gas, the present invention provides a cleaning treatment device for sulfur-containing tail gas and a treatment method for sulfur-containing tail gas. By using the device and method, hydrogen peroxide is used as a removal agent, and water is formed after the reaction, which then absorbs SO3 oxidized by hydrogen peroxide to form sulfuric acid, which is recycled and reused. Finally, SO2 in the tail gas is ≤35mg / Nm 3 , Acid mist content ≤5mg / Nm 3 , can meet emission standards and eliminate odors and harmful substances in the environment.

[0004] The present invention is achieved through the following technical solutions: A cleaning treatment device for sulfur-containing tail gas comprises a tail gas washing tower, an acid removal tower, a vent pipe and a circulating liquid cooler; the gas outlet of the tail gas washing tower is connected to the acid removal tower, the gas outlet of the acid removal tower is connected to the vent pipe, and the liquid outlet of the acid removal tower is connected to the circulating liquid cooler; the tail gas washing tower and the circulating liquid cooler form a circulation passage to cool the acid liquid discharged from the lower end of the tail gas washing tower; the tail gas washing tower is connected to a hydrogen peroxide input passage for introducing hydrogen peroxide; the acid removal tower is connected to a desalted water input passage for introducing desalted water.

[0005] Furthermore, the tail gas washing tower is filled with upper and lower sections of fillers, and spray devices are respectively arranged above the upper and lower sections of fillers, and the spray devices are respectively connected to the hydrogen peroxide input passage; the acid liquid cooled by the circulating liquid cooler enters the spray device on the lower section of the tail gas washing tower filler, and is sprayed after mixing with the entering hydrogen peroxide; the acid removal tower includes a section of filler, and a spray device is arranged on the upper end of the filler, and the spray device is connected to the desalted water input passage.

[0006] Furthermore, a demister is provided at the upper end of the tail gas washing tower; and the number of spray devices at the upper section of the tail gas washing tower is greater than that at the lower section.

[0007] Furthermore, the fillers in the tail gas washing tower and the acid removal tower are PP flat rings, the edges of which are covered with serrated structures, and the four leaf-shaped structures in the middle are evenly distributed in a ring shape and extend inward, crossing and bending upward and downward.

[0008] Furthermore, the tail gas scrubber forms a circulation passage through a circulation pump and a circulation liquid cooler.

[0009] Furthermore, check valves are provided on the connecting pipelines between the acid removal tower and the tail gas washing tower, and between the circulating liquid cooler and the tail gas washing tower to prevent backflow.

[0010] In the present invention, the method for treating sulfur-containing tail gas by the device comprises the following steps: 1) The sulfur-containing tail gas enters the tail gas scrubber from the bottom of the tail gas scrubber and contacts with hydrogen peroxide and acid in the circulating liquid cooler in countercurrent. Hydrogen peroxide oxidizes the tail gas and eventually forms sulfur trioxide, which reacts with water in the system to form dilute acid. 2) Step 1) The tail gas treated by the tail gas scrubber enters the deacidification tower from the gas outlet of the tail gas scrubber, and is countercurrently contacted with the desalted water added into the deacidification tower to remove the trace acid mist entrained, and the treated tail gas enters the vent pipe for discharge, and the acid solution absorbing the acid mist enters the circulating liquid cooler; 3) Step 1) The acid liquid produced in the tail gas scrubber enters the circulating liquid cooler, and the acid liquid in the circulating liquid cooler is circulated into the tail gas scrubber after being cooled.

[0011] Furthermore, in step 1), the concentration of hydrogen peroxide is 25-60%; and in step 3), the cooling medium of the circulating liquid cooler is cooling water at 10-20°C.

[0012] Furthermore, in step 1), the amount of sulfur-containing tail gas entering the tail gas scrubber is 20000 Nm 3 / h; the amount of hydrogen peroxide entering the tail gas washing tower is 15~30kg / h; the amount of desalted water entering the acid removal tower is 10kg / h.

[0013] Furthermore, in step 3), when the concentration of sulfuric acid in the circulating liquid cooler reaches 40% or more, it is sent out. Beneficial Effects The sulfur-containing tail gas cleaning treatment device of the present invention has a simple structure. The device is used to treat the sulfur-containing tail gas, and the final tail gas SO2≤35mg / Nm 3 , Acid mist content ≤5mg / Nm 3 , can meet emission standards, eliminate odors and harmful substances in the environment, and the sulfur in the tail gas forms sulfuric acid, which can be discharged to the circulating water station to adjust the pH, turning waste into treasure, using hydrogen peroxide as a remover, forming water after reaction, without adding other ingredients, to achieve the purpose of clean production. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the cleaning treatment device for sulfur-containing tail gas of the present invention, 1. tail gas washing tower, 2. acid removal tower, 3. vent pipe, 4. circulation pump, 5. circulation liquid cooler; Figure 2 Schematic diagram of random packing structure. DETAILED DESCRIPTION

[0015] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is clearly and completely described below. Based on the embodiments in this application, other similar embodiments obtained by ordinary technicians in this field without making any creative work should all fall within the scope of protection of this application.

[0016] The schematic diagram of the cleaning treatment device for sulfur-containing tail gas in the present invention is as follows Figure 1 As shown, 1 is a tail gas washing tower, 2 is an acid removal tower, 3 is a vent pipe, 4 is a circulating pump, and 5 is a circulating liquid cooler; Figure 2 Schematic diagram of random packing structure.

[0017] Depend on Figure 1As shown, the cleaning treatment device for sulfur-containing tail gas in the present invention includes a tail gas washing tower 1), an acid removal tower 2, a vent pipe 3 and a circulating liquid cooler 5; the gas outlet of the tail gas washing tower 1 is connected to the acid removal tower 2, the gas outlet of the acid removal tower 2 is connected to the vent pipe, and the liquid outlet of the acid removal tower is connected to the circulating liquid cooler 5; the tail gas washing tower 1 and the circulating liquid cooler 5 form a circulation passage for cooling the acid liquid discharged from the lower end of the tail gas washing tower 1; the tail gas washing tower 1 is connected to the hydrogen peroxide input passage for introducing hydrogen peroxide; the acid removal tower 2 is connected to the desalted water input passage for introducing desalted water.

[0018] The tail gas washing tower 1 described above is filled with upper and lower sections of fillers, and spray devices are respectively arranged above the upper and lower sections of fillers, and the spray devices are respectively connected to the hydrogen peroxide input passage; the acid liquid cooled by the circulating liquid cooler 5 enters the spray device on the lower section of the tail gas washing tower 1, and is mixed with the hydrogen peroxide and then sprayed; the deacidification tower 2 includes a section of filler, and a spray device is arranged on the upper end of the filler, and the spray device is connected to the desalted water input passage; the upper end of the tail gas washing tower 1 is provided with a defoamer; the spray device on the upper section of the tail gas washing tower The number of spray devices in the upper section is more than that in the lower section, and the number of spray devices in the upper section is 1.2 times that of the spray devices in the lower section; the fillers in the exhaust gas washing tower 1 and the deacidification tower 2 are PP flat rings, the edges of the flat rings are covered with serrated structures, and the four leaf-shaped structures in the middle are evenly distributed in a ring shape and extend inward, cross-bending upward and downward; the exhaust gas washing tower 1 forms a circulation passage through the circulating pump 4 and the circulating liquid cooler 5; the connecting pipelines between the deacidification tower 2 and the exhaust gas washing tower 1, and between the circulating liquid cooler 5 and the exhaust gas washing tower 1 are provided with check valves to prevent backflow.

[0019] The exhaust gas cleaning treatment device of the present invention is used to illustrate the method for treating sulfur-containing exhaust gas of the present invention in combination with specific embodiments. The main components of the sulfur-containing exhaust gas of the present invention are N2: 72%, O2: 8.5%, CO2: 17%, and SO2: 325ppm.

[0020] Example 1 1) The sulfur-containing tail gas enters the tail gas washing tower 1 from the bottom of the tail gas washing tower 1 (the flow rate of the sulfur-containing tail gas entering the tail gas washing tower (1) is 20000Nm 3 / h, countercurrently contacted with 50wt% hydrogen peroxide (the total flow rate of hydrogen peroxide into the tail gas scrubber (1) is 16.5kg / h) and the acid solution in the circulating liquid cooler 5, the hydrogen peroxide oxidizes the tail gas, oxidizes sulfur dioxide, and finally forms sulfur trioxide, which reacts with water in the system to form dilute acid solution; 2) Step 1) The tail gas treated by the tail gas washing tower 1 enters the deacidification tower 2 from the gas outlet of the tail gas washing tower 1, and is countercurrently contacted with the desalted water added into the deacidification tower 2 to remove the trace acid mist entrained (the flow rate of the desalted water into the deacidification tower 2 is 10 kg / h), and the treated tail gas enters the vent pipe 3 for discharge, and the acid solution absorbing the acid mist enters the circulating liquid cooler 5; 3) Step 1) The acid liquid produced by the tail gas washing tower enters the circulating liquid cooler 5 (the cooling medium is cooling water at 15°C), and the acid liquid in the circulating liquid cooler 5 is circulated into the tail gas washing tower 1 after cooling; when the concentration of sulfuric acid in the circulating liquid cooler 5 reaches more than 40%, it is sent out to the circulating water station for adjusting the pH, turning waste into treasure.

[0021] The SO2 content in the tail gas after treatment in this embodiment is 35 mg / Nm 3 , acid mist content is 5mg / Nm 3 , which can achieve ultra-low emissions.

[0022] Example 2 1) The sulfur-containing tail gas enters the tail gas washing tower 1 from the bottom of the tail gas washing tower 1 (the flow rate of the sulfur-containing tail gas entering the tail gas washing tower 1 is 20000Nm 3 / h, countercurrently contacted with 27.5wt% hydrogen peroxide (the total flow rate of hydrogen peroxide into the tail gas scrubber 1 is 29kg / h) and the acid solution in the circulating liquid cooler 5, the hydrogen peroxide oxidizes the tail gas, oxidizes sulfur dioxide, and finally forms sulfur trioxide, and the sulfur trioxide reacts with the water in the system to form a dilute acid solution; 2) Step 1) The tail gas treated by the tail gas washing tower 1 enters the deacidification tower 2 from the gas outlet of the tail gas washing tower 1, and is countercurrently contacted with the desalted water added into the deacidification tower 2 to remove the trace acid mist entrained (the flow rate of the desalted water into the deacidification tower 2 is 10 kg / h), and the treated tail gas enters the vent pipe 3 for discharge, and the acid solution absorbing the acid mist enters the circulating liquid cooler 5; 3) Step 1) The acid liquid produced by the tail gas washing tower enters the circulating liquid cooler 5 (the cooling medium is cooling water at 20°C), and the acid liquid in the circulating liquid cooler 5 is circulated into the tail gas washing tower 1 after cooling; when the concentration of sulfuric acid in the circulating liquid cooler 5 reaches more than 40%, it is sent out to the circulating water station for adjusting pH, turning waste into treasure.

[0023] The SO2 content in the tail gas after treatment in this embodiment is 200 mg / Nm 3 , acid mist content is 5mg / Nm 3 , which can meet the emission standards of sulfuric acid industry.

[0024] Comparative Example 1 1) The sulfur-containing tail gas enters the tail gas washing tower 1 from the bottom of the tail gas washing tower 1 (the flow rate of the sulfur-containing tail gas entering the tail gas washing tower 1 is 20000Nm3 / h, countercurrently contacted with 5wt% hydrogen peroxide (the total flow rate of hydrogen peroxide into the tail gas scrubber 1 is 160kg / h) and the acid solution in the circulating liquid cooler 5, the hydrogen peroxide oxidizes the tail gas, oxidizes sulfur dioxide, and finally forms sulfur trioxide, and the sulfur trioxide reacts with the water in the system to form a dilute acid solution; 2) Step 1) The tail gas treated by the tail gas washing tower 1 enters the deacidification tower 2 from the gas outlet of the tail gas washing tower 1, and is countercurrently contacted with the desalted water added into the deacidification tower 2 to remove the trace acid mist entrained (the flow rate of the desalted water into the deacidification tower 2 is 10 kg / h), and the treated tail gas enters the vent pipe 3 for discharge, and the acid solution absorbing the acid mist enters the circulating liquid cooler 5; 3) Step 1) The acid liquid produced by the tail gas washing tower enters the circulating liquid cooler 5 (the cooling medium is cooling water at 15°C), and the acid liquid in the circulating liquid cooler 5 is circulated into the tail gas washing tower 1 after cooling; when the concentration of sulfuric acid in the circulating liquid cooler 5 reaches more than 40%, it is sent out to the circulating water station for adjusting the pH, turning waste into treasure.

[0025] In this comparative case, the SO2 content in the treated tail gas is 500mg / Nm 3 , acid mist content is 5mg / Nm 3 , and cannot meet emission standards.

Claims

1. A cleaning treatment device for sulfur-containing tail gas, characterized in that: It comprises an exhaust gas washing tower (1), an acid removal tower (2), a vent pipe (3) and a circulating liquid cooler (5); The gas outlet of the tail gas washing tower (1) is connected to the deacidification tower (2), the gas outlet of the deacidification tower (2) is connected to the vent pipe, and the liquid outlet of the deacidification tower is connected to the circulating liquid cooler (5); The tail gas washing tower (1) and the circulating liquid cooler (5) form a circulation passage to cool the acid liquid discharged from the lower end of the tail gas washing tower (1); The tail gas washing tower (1) is connected to the hydrogen peroxide input passage for introducing hydrogen peroxide; the deacidification tower (2) is connected to the desalted water input passage for introducing desalted water.

2. The cleaning treatment device for sulfur-containing tail gas according to claim 1, characterized in that: The tail gas washing tower (1) is filled with upper and lower sections of fillers, and spray devices are respectively arranged above the upper and lower sections of fillers, and the spray devices are respectively connected to the hydrogen peroxide input passage; the acid liquid cooled by the circulating liquid cooler (5) enters the spray device on the lower section of the tail gas washing tower (1) and is mixed with the hydrogen peroxide before being sprayed; the deacidification tower (2) includes a section of filler, and a spray device is arranged on the upper end of the filler, and the spray device is connected to the desalted water input passage.

3. The cleaning treatment device for sulfur-containing tail gas according to claim 2 is characterized in that: The tail gas washing tower (1) is provided with a demister at the upper end; the number of spray devices at the upper section of the tail gas washing tower is greater than that at the lower section.

4. The cleaning treatment device for sulfur-containing tail gas according to claim 2 is characterized in that: The fillers in the tail gas washing tower (1) and the acid removal tower (2) are PP flat rings, the edges of which are covered with serrated structures, and the four leaf-shaped structures in the middle are evenly distributed in a ring shape and extend inward, crossing and bending upward and downward.

5. The cleaning treatment device for sulfur-containing tail gas according to claim 1, characterized in that: The tail gas scrubber (1) forms a circulation passage through a circulation pump (4) and a circulation liquid cooler (5).

6. The cleaning treatment device for sulfur-containing tail gas according to claim 1, characterized in that: Check valves are provided on the connecting pipelines between the acid removal tower (2) and the tail gas washing tower (1), and between the circulating liquid cooler (5) and the tail gas washing tower (1) to prevent backflow.

7. A method for treating sulfur-containing tail gas using the device according to any one of claims 1 to 6, characterized in that: The following steps are involved: 1) The sulfur-containing tail gas enters the tail gas washing tower (1) from the bottom of the tail gas washing tower (1), and is countercurrently contacted with hydrogen peroxide and acid in the circulating liquid cooler (5), and the hydrogen peroxide oxidizes the tail gas to eventually form sulfur trioxide, and the sulfur trioxide reacts with water in the system to form a dilute acid solution; 2) Step 1) The tail gas treated in the tail gas washing tower (1) enters the acid removal tower (2) from the gas outlet of the tail gas washing tower (1), and is countercurrently contacted with the desalted water added to the acid removal tower (2) to remove the trace acid mist entrained, and the treated tail gas enters the vent pipe (3) for discharge, and the acid solution that absorbs the acid mist enters the circulating liquid cooler (5); 3) Step 1) The acid liquid generated in the tail gas scrubber enters the circulating liquid cooler (5), and the acid liquid in the circulating liquid cooler (5) is cooled and then circulated into the tail gas scrubber (1).

8. The method for treating sulfur-containing tail gas according to claim 7, characterized in that: In step 1), the concentration of hydrogen peroxide is 25-60%; in step 3), the cooling medium of the circulating liquid cooler (5) is cooling water at 10-20°C.

9. The method for treating sulfur-containing tail gas according to claim 7, characterized in that: In step 1), the amount of sulfur-containing tail gas entering the tail gas scrubber (1) is 20000 Nm 3 / h; the amount of hydrogen peroxide entering the tail gas washing tower (1) is 15~30kg / h; the amount of desalted water entering the deacidification tower (2) is 10kg / h.

10. The method for treating sulfur-containing tail gas according to claim 7, characterized in that: Step 3) When the concentration of sulfuric acid in the circulating liquid cooler (5) reaches 40% or more, it is sent out.

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