Purification process for resource-based treatment of tail gas from coking desulfurization wastewater

Abstract

This invention discloses a purification process for the resource-based treatment of tail gas from coking desulfurization wastewater, comprising the following steps: tail gas from the catalytic conversion process of the desulfurization wastewater is pressurized by a blower via a pipeline; the pressurized tail gas is then piped to the top of the coke oven; 3-8 carbonization chambers are selected at the top of the coke oven, and perforations are made in the refractory bricks under the coal charging hole cover furthest from the riser pipe in each carbonization chamber; the pressurized tail gas is sent into the carbonization chamber for pyrolysis treatment via the coal charging hole. This invention effectively purifies the acidic gases containing hydrogen sulfide, carbonyl sulfide, and carbon dioxide generated during the catalytic conversion process, reduces the risk of ammonia escape, and solves problems such as high washing liquid consumption and poor purification effect, thus ensuring purification effect while reducing operating costs.

Description

Technical Field

[0001] This invention relates to a process for treating tail gas during the resource recovery of coking desulfurization waste liquid, specifically a purification process for acidic tail gas generated during the catalytic conversion stage of coking desulfurization waste liquid resource recovery, belonging to the field of waste gas treatment technology. Background Technology

[0002] During the wet desulfurization process of coke oven gas, inorganic salts such as ammonium thiosulfate, ammonium thiocyanate, and ammonium sulfate are produced due to side reactions. Because the desulfurization wastewater contains relatively high levels of these byproducts, direct discharge not only causes serious environmental pollution but also wastes resources. Currently, salt extraction and acid production technologies are mainly used to treat them. However, due to limited market capacity for ammonium thiocyanate, salt extraction technology faces problems such as unsaleable products and secondary pollution. While acid production technology converts sulfur from sulfur and wastewater into sulfuric acid through high-temperature incineration and conversion processes, the process easily produces more difficult-to-treat dilute acids. Furthermore, acid production technology suffers from complex processes, high investment costs, and unstable operation.

[0003] To address the existing problems in the treatment of desulfurization wastewater, Li Guoqiang et al. (Chinese Patent ZL 201911237777.9) developed a resource-based treatment process for desulfurization wastewater. This process converts ammonium thiocyanate and ammonium thiosulfate into ammonium sulfate, achieving a gentle salt conversion and solving problems such as by-product salts and water balance in the desulfurization system. During this process, the wastewater generates acidic gases containing hydrogen sulfide, carbonyl sulfide, and carbon dioxide during catalytic conversion. This process primarily involves washing with the desulfurization liquid, followed by gas treatment before discharge. However, this process carries the risk of ammonia escape from the desulfurization liquid, and also suffers from high liquid consumption and poor purification efficiency. Therefore, developing a new and effective treatment process for this tail gas is of great significance for achieving cleaner resource-based treatment of coking desulfurization wastewater. Summary of the Invention

[0004] This invention aims to provide a process for treating tail gas during the resource-based treatment of coking desulfurization waste liquid. The acidic tail gas generated during the conversion of desulfurization waste liquid is pressurized by a blower and sent into a carbonization chamber for pyrolysis treatment. During the transportation process, equipment such as flame arresters, manual and automatic valves, and pressure sensors are installed to ensure that the tail gas is purified safely and efficiently.

[0005] This invention primarily targets sulfur-containing tail gas generated during the resource-based treatment of desulfurization wastewater. Treating this tail gas separately requires a scrubbing tower and scrubbing liquid purification equipment, which not only increases initial investment but also raises operating costs due to scrubbing liquid consumption, and poses a risk of secondary pollution. Since the tail gas contains no oxidizing gases and its components, such as hydrogen sulfide, are identical to those in coal gas, it can be incorporated into the coal gas system and purified using existing methods. This fully sealed system eliminates the risk of secondary pollution and also reduces investment and operating costs.

[0006] This invention provides a purification process for the resource-based treatment of tail gas from coking desulfurization wastewater, comprising the following steps:

[0007] (1) The tail gas from the catalytic conversion process of desulfurization waste liquid is sent to the blower through the pipeline for pressurization;

[0008] (2) The exhaust gas is pressurized by a blower and then sent to the top of the coke oven through a pipeline;

[0009] (3) Select 3-8 carbonization chambers on the top of the coke oven and make holes in the refractory bricks under the coal charging hole (smoke guide hole) farthest from the riser pipe in each carbonization chamber;

[0010] (4) The pressurized tail gas in (2) is sent into the carbonization chamber through a pipeline for pyrolysis treatment.

[0011] Furthermore, considering the specific exhaust gas pressurization process, the above purification process includes the following steps:

[0012] (1) The exhaust gas pressure is detected by a pressure transmitter at the exhaust gas outlet pipe;

[0013] (2) The pressure transmitter at the exhaust gas outlet pipe is interlocked with the fan and pneumatic valve connected to the back; when the detected exhaust gas pressure is greater than 100Pa, the fan at the back starts and the pneumatic valve opens to start transporting exhaust gas; when the detected exhaust gas pressure is less than 100Pa, the fan at the back runs at 15Hz and the valve after the fan is closed to end the transport of exhaust gas.

[0014] (3) The fan is controlled by frequency conversion. When the pressure of the exhaust gas delivered in front of the fan is higher than 500Pa, the fan operates at 50Hz. When the pressure is between 100-500Pa, the frequency of the fan is calculated according to the following formula: To maintain the pressure at the exhaust outlet within the range of 100-500Pa, ensuring normal gas delivery;

[0015] (4) The exhaust gas enters the carbonization chamber for pyrolysis through five coal charging channels that are furthest from the riser pipe via pipelines.

[0016] (5) When the carbonization chamber of the treated tail gas is in the discharge state, close the manual regulating valve of the corresponding branch pipe. After the coal discharge is completed, open the manual regulating valve again.

[0017] To ensure a safer and cleaner implementation of this process, the following additional facilities and technologies are incorporated into the above technical solution:

[0018] Within the waste liquid conversion unit area, automatic valves, flame arresters, pressure transmitters, and local display micro-pressure gauges are installed on the exhaust gas pipeline from the conversion reactor to the blower. Automatic valves and pressure gauges are also installed on the pipeline downstream of the blower. To ensure absolute safety during the transport process, the pressure gauges before and after the blower should have remote transmission capabilities in addition to local display, and the blower should have frequency conversion functionality. During operation, the blower and automatic valves are interlocked by setting upper and lower pressure limits (ranging from 100-500 Pa): the pressure value before the blower is interlocked with the blower frequency, and the blower operation is interlocked with the automatic valves before and after the blower. When the pressure before the blower is below the lower limit, the blower operates at the lowest frequency, and the valve downstream of the blower automatically closes. When the pressure is greater than or equal to the upper limit, the blower operates at full frequency, and the valve downstream of the blower automatically opens. The blower frequency is determined based on the ratio of the current pressure to the set upper and lower pressure limits, thus ensuring that the pressure before the blower remains between the set upper and lower limits.

[0019] After the coal charging hole (smoke guide hole) of the carbonization chamber on the top of the furnace is opened, the gap between the hole wall and the inlet pipe is sealed with refractory mud to ensure that the raw coal gas in the coking process will not escape into the environment.

[0020] Valves and flame arresters are installed on the branch pipes that introduce acidic tail gas into each carbonization chamber. When the coal charging hole (smoke guide hole) cover is opened, the valves on the corresponding branch pipes are closed in time, and when the coal charging hole (smoke guide hole) cover is closed, the valves on the corresponding branch pipes are opened in time.

[0021] Flame arresters, valves, and pressure gauges are installed on the main exhaust gas conveying pipe at the top of the furnace. When the pressure on the main conveying pipe is lower than the lower pressure limit, the valves on the main pipe are closed manually or automatically in a timely manner. When the pressure on the main conveying pipe is higher than the upper pressure limit, the valves on the main pipe are opened manually or automatically in a timely manner. Each branch pipe that introduces acidic exhaust gas into each carbonization chamber is equipped with valves and flame arresters. When the coal charging hole cover of the corresponding carbonization chamber needs to be opened during the coal charging and coking process, the valve on the corresponding branch pipe should be closed to ensure the safety of the conveying process.

[0022] The beneficial effects of this invention are:

[0023] This invention effectively purifies the acidic gases containing hydrogen sulfide, carbonyl sulfide, and carbon dioxide that are generated during the catalytic conversion process, reducing the risk of ammonia escape. It also solves problems such as high washing liquid consumption and poor purification effect, thus ensuring purification effect while reducing operating costs. Attached Figure Description

[0024] Figure 1 This is a diagram of the purification device for the resource-based treatment of tail gas from coking desulfurization wastewater according to the present invention.

[0025] In the diagram: 1 is a pressure transmitter, 2 is a blower, 3 is a pneumatic valve, 4 is a pressure gauge, 5 is a valve, 6 is a flame arrester, 7 is a waste liquid conversion reactor, 8 is an inlet pipe, 9 is a coal charging hole in the carbonization chamber, 10 is a coke oven, 11 is a gas collecting pipe, 12 is raw coal gas, and 13 is a tail gas conveying main pipe. Detailed Implementation

[0026] The present invention will be further illustrated by the following embodiments, but is not limited to the following embodiments.

[0027] This invention provides a purification process for the resource-based treatment of tail gas from coking desulfurization wastewater, comprising the following steps:

[0028] (1) First, the tail gas from the catalytic conversion process of desulfurization waste liquid is introduced into the pipeline, and the pressure transmitter 1 at the tail gas outlet pipeline will detect the pressure at the reactor outlet.

[0029] (2) The exhaust gas is sent to the blower through the pipeline for pressurization:

[0030] The pressure transmitter 1 at the exhaust gas outlet pipe is interlocked with the fan 2 and pneumatic (electric) valve 3 of the downstream equipment. When the pressure before the fan is greater than 100Pa, the downstream fan starts, the pneumatic (electric) valve opens, and exhaust gas begins to be delivered. When the pressure before the fan is less than 100Pa, the downstream fan operates at 15Hz, and the valve after the fan closes, ending the delivery of exhaust gas.

[0031] (3) The fan is controlled by frequency conversion. When the pressure in front of the fan is higher than 500Pa, the fan runs at 50HZ. When the pressure is between 100-500Pa, the frequency of the fan is automatically calculated and determined by the system according to the following formula: This ensures that the pressure at the exhaust outlet is maintained within the range of 100-500 Pa, guaranteeing normal gas delivery.

[0032] (4) The exhaust gas enters the carbonization chamber for pyrolysis through five coal charging channels that are furthest from the riser pipe via pipelines.

[0033] (5) When the carbonization chamber of the treated tail gas is in the discharge state, close the manual regulating valve of the corresponding branch pipe. After the coal discharge is completed, open the manual regulating valve again.

[0034] Specifically, such as Figure 1 As shown, the exhaust gas originates from the waste liquid conversion reactor 7. An automatic valve, flame arrester, pressure transmitter 1, and a local display micro-pressure gauge are installed on the exhaust gas pipeline from the conversion reactor to the blower. A pneumatic valve 3 and pressure gauges are installed on the pipeline after the blower 2. To ensure absolute safety during the transportation process, the pressure gauges before and after the blower should have remote transmission capabilities in addition to local display, and the blower should have frequency conversion functionality. During operation, the blower 2 and pneumatic valve 3 are interlocked by setting upper and lower pressure limits (the range of the upper and lower limits is 100-500 Pa): the pressure value before the blower is interlocked with the blower frequency, and the blower operation is interlocked with the pneumatic valves 3 before and after the blower. When the pressure before the blower is lower than the lower limit, the blower operates at the lowest frequency, and the valve after the blower automatically closes. When the pressure is greater than or equal to the upper limit, the blower operates at full frequency, and the valve after the blower automatically opens. The blower frequency is determined based on the ratio of the current pressure to the set upper and lower pressure limits, thereby ensuring that the pressure before the blower is maintained between the set upper and lower limits.

[0035] After the coal charging hole 9 (smoke guide hole) of the carbonization chamber on the top of the furnace is opened, the gap between the hole wall and the inlet pipe 8 is sealed with refractory mud to ensure that the raw coal gas 12 in the coking process will not escape into the environment.

[0036] A valve 5 and a flame arrester 6 are installed on the branch pipe that introduces acidic tail gas into each carbonization chamber. When the coal charging hole (smoke guide hole) cover is opened, the valve on the corresponding branch pipe is closed in time, and when the coal charging hole (smoke guide hole) cover is closed, the valve on the corresponding branch pipe is opened in time.

[0037] A flame arrester 6, a valve 5, and a pressure gauge 4 are installed on the tail gas conveying main pipe 13 at the top of the furnace. When the pressure on the conveying main pipe is lower than the lower pressure limit, the valve on the main pipe is closed manually or automatically in time. When the pressure on the conveying main pipe is higher than the upper pressure limit, the valve on the main pipe is opened manually or automatically in time. Each branch pipe that introduces acidic tail gas into each carbonization chamber is equipped with a valve and a flame arrester. When the coal charging hole cover of the corresponding carbonization chamber needs to be opened during the coal charging and coking process, the valve on the corresponding branch pipe should be closed to ensure the safety of the conveying process.

Claims

1. A purification process for the resource-based treatment of tail gas from coking desulfurization wastewater, characterized in that... Includes the following steps: (1) The tail gas from the catalytic conversion process of desulfurization waste liquid is sent to the blower through the pipeline for pressurization; the tail gas comes from the waste liquid conversion reactor; (2) The exhaust gas is pressurized by the blower and then sent to the top of the coke oven through the pipeline; (3) Select 3-8 carbonization chambers at the top of the coke oven and make holes in the refractory bricks under the coal charging hole cover that is furthest from the riser pipe in each carbonization chamber; (4) The pressurized tail gas in (2) is sent into the carbonization chamber through the coal charging channel via the pipeline for pyrolysis treatment.

2. The purification process for treating tail gas from coking desulfurization wastewater according to claim 1, characterized in that: The process of pressurizing the exhaust gas by the fan is as follows: (1) The pressure of the exhaust gas is detected by a pressure transmitter at the exhaust gas outlet pipe; (2) The pressure transmitter at the exhaust gas outlet pipeline is interlocked with the fan and pneumatic valve connected to the rear. When the detected exhaust gas pressure is greater than 100Pa, the fan at the rear starts and the pneumatic valve opens to start transporting exhaust gas. When the detected exhaust gas pressure is less than 100Pa, the fan at the rear runs at 15Hz and the valve after the fan is closed to end the transport of exhaust gas. (3) The fan is controlled by frequency conversion. When the pressure of the exhaust gas delivered at the front of the fan is higher than 500Pa, the fan operates at 50Hz. When the pressure is between 100-500Pa, the frequency of the fan is calculated according to the following formula: To maintain the pressure at the exhaust outlet within the range of 100-500Pa, ensuring normal gas delivery.

3. The purification process for treating tail gas from coking desulfurization wastewater according to claim 1, characterized in that: Automatic valves, flame arresters, pressure transmitters, and local micro-pressure gauges are installed on the exhaust gas pipeline from the waste liquid conversion reactor to the blower. Automatic valves and pressure gauges are installed on the pipeline after the blower. During operation, the upper and lower pressure limits of the blower are set to 100-500 Pa to achieve interlocking of the blower and automatic valves: the pressure value before the blower is interlocked with the blower frequency, and the operation of the blower is interlocked with the automatic valves before and after the blower. When the pressure before the blower is lower than the lower limit, the blower operates at the lowest frequency, and the valve after the blower automatically closes. When the pressure before the blower is greater than or equal to the upper limit, the blower operates at full frequency, and the valve after the blower automatically opens.

4. The purification process for treating tail gas from coking desulfurization wastewater according to claim 1, characterized in that: After the coal charging hole in the carbonization chamber at the top of the coke oven is opened, the gap between the hole wall and the tail gas inlet pipe is sealed with refractory mud to ensure that the raw coal gas in the coke oven process does not escape into the environment.

5. The purification process for treating tail gas from coking desulfurization wastewater according to claim 4, characterized in that: Valves and flame arresters are installed on the branch pipes that introduce tail gas into each carbonization chamber. When coke is discharged, the valves on the corresponding branch pipes are closed in time, and when the coal charging hole cover is closed, the valves on the corresponding branch pipes are opened in time.

6. The purification process for treating tail gas from coking desulfurization wastewater according to claim 1, characterized in that: Flame arresters, valves, and pressure gauges are installed on the tail gas conveying main pipe at the top of the coke oven. When the pressure on the conveying main pipe is lower than the lower pressure limit, the valves on the main pipe are closed manually or automatically in a timely manner. When the pressure on the conveying main pipe is higher than the upper pressure limit, the valves on the main pipe are opened manually or automatically in a timely manner.

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