A purification system and method for unorganized flue gas emission from skylight of electrolysis workshop

Abstract

The present invention relates to a purification system and method for unorganized flue gas emitted from a skylight in an electrolysis workshop, comprising an absorption liquid, a mixing tank, a water inlet main pipe, a water inlet branch pipe, a spray device, a drainage riser pipe, and a drainage transverse pipe, wherein the absorption liquid is stored in the mixing tank; the water inlet main pipe is arranged on both sides of the skylight ventilator in the electrolysis workshop, one end of which is connected to the mixing tank through a water pump, and the other end is a closed port; the water inlet branch pipe is arranged on the water inlet main pipe, and the spray device is arranged at the end of the water inlet branch pipe; the drainage transverse pipe is arranged on both sides of the skylight ventilator in the electrolysis workshop in parallel with the water inlet main pipe, one end of which is connected to the mixing tank, and the other end is a closed port; the drainage riser is arranged on the drainage transverse pipe through a 45° inclined tee, and its water inlet is connected to the drainage grooves on both sides of the skylight ventilator in the electrolysis workshop. The present invention performs adsorption treatment on the unorganized flue gas emitted from the electrolysis skylight to achieve the purpose of purifying the flue gas, while reducing pollutant emissions and alleviating environmental pollution, providing prerequisites for pollutant recycling and resource utilization.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum electrolysis fume and waste gas treatment, and in particular relates to a system and method for purifying unorganized fume emitted from a skylight in an electrolysis workshop. Background Art

[0002] During the production of electrolytic aluminum, fluoride salts such as aluminum fluoride and cryolite melt into electrolytes under high temperature conditions, and aluminum oxide melts in the electrolyte. Under the action of direct current, an electrochemical reaction occurs in the electrolytic cell, and metallic aluminum is precipitated at the cathode. The fluoride in the electrolyte reacts with the raw materials and moisture in the air to generate HF, and reacts with carbon and sulfur elements to generate gaseous pollutants such as CF4, C2F6, and SO2. These pollutants are emitted from the electrolytic cell and mixed with fluoride dust caused by production operations to form electrolytic flue gas. Most of the gaseous and solid fluorides in the electrolytic flue gas are collected by the electrolytic cell gas hood and enter the flue gas purification system for treatment, but some flue gas is still emitted from the gaps in the upper structure of the electrolytic cell and is unorganizedly discharged into the atmosphere through the skylight of the electrolytic workshop, causing a certain degree of environmental pollution. The skylight area of ​​the electrolytic workshop is large, and the gas has strong unorganized fluidity. Therefore, a purification system and purification method for the unorganized flue gas emitted from the electrolytic skylight are urgently needed. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides a system and method for purifying the unorganized flue gas emitted from the skylight of an electrolysis workshop, which adsorbs and collects the unorganized flue gas emitted from the electrolysis skylight, thereby achieving the purpose of purifying the flue gas and achieving zero overflow. While reducing pollutant emissions and alleviating environmental pollution, it provides the necessary conditions for the feasibility of pollutant recovery and resource utilization.

[0004] A purification system for unorganized flue gas emitted from a skylight in an electrolysis workshop, comprising an absorption liquid, a mixing tank, a water inlet main pipe, a water inlet branch pipe, a spray device, a drainage riser pipe, and a drainage transverse pipe, wherein the absorption liquid is a sodium hydroxide solution or seawater with a mass concentration of 0.1 to 42%, which is stored in the mixing tank; the water inlet main pipe is arranged on both sides of a skylight ventilator in the electrolysis workshop, one end of which is connected to the mixing tank through a water pump, and the other end is a closed port; a liquid level gauge is provided in the mixing tank, and the liquid level gauge and the water pump are electrically connected to a control room in the electrolysis workshop; the water inlet branch pipe is arranged on the water inlet main pipe and communicates with the water inlet main pipe, and the spray device is arranged at the end of the water inlet branch pipe and communicates with the water inlet branch pipe , the spraying direction points to the skylight ventilator in the electrolysis workshop; a control main valve is arranged on the water inlet main pipe between the water pump and the spraying device, and a branch line control valve is arranged on the water inlet branch pipe, which is electrically connected to the control room of the electrolysis workshop; a flow meter is arranged on the water inlet branch pipe, and the flow meter is electrically connected to the control room of the electrolysis workshop; the drainage horizontal pipe is arranged on both sides of the skylight ventilator in the electrolysis workshop in parallel with the water inlet main pipe, one end is connected to the mixing tank, and the other end is a closed port; the drainage riser is arranged on the drainage horizontal pipe through a 45° inclined tee, and the water inlet of the drainage riser is connected to the drainage grooves on both sides of the skylight ventilator in the electrolysis workshop; the other end of the 45° inclined tee is connected to the rainwater downpipe of the building body;

[0005] The spray device is a spray nozzle, the spray angle of the spray nozzle is 10° to 135°, the particle size of the spray droplets is 0.1 to 1 mm, and the spray shape is fan-shaped, hollow cone-shaped or filled cone-shaped.

[0006] The material of the mixing tank cannot react with the absorption liquid.

[0007] The above-mentioned purification method of the purification system of the unorganized flue gas emitted from the skylight of the electrolysis workshop comprises the following steps:

[0008] Step 1: Preparation: Prepare a sodium hydroxide solution or seawater with a mass concentration of 0.1-42% as an absorption liquid and store it in a preparation tank;

[0009] Step 2: Pressurization: The absorption liquid in step 1 is pressurized by a water pump, and the absorption liquid is transported to the spraying device through the water inlet main pipe and the water inlet branch pipe;

[0010] Step 3: Purification: The pressurized absorption liquid in step 2 is sprayed out through the spray device and fully contacts with the electrolytic flue gas discharged from the ventilator, so that the flue gas pollutants fully contact and react with the absorption liquid to purify the soluble substances in the flue gas. The principle is as follows:

[0011] NaOH+HF→NaF+H2O

[0012] 2NaOH+SO2→Na2SO3+H2O;

[0013] Step 4: Collection: The absorption liquid that has been in full contact with the electrolytic flue gas in step 3 is discharged along the rain shield in the ventilator, collected in the drainage trough of the ventilator, flows along the drainage trough to the drainage riser, flows through the drainage riser to the drainage cross pipe, and finally flows back to the mixing tank. The absorption liquid is recycled until it is saturated, and then it is treated with impurity removal, fluorine removal, sulfur removal, and calcium removal.

[0014] The beneficial effects of the present invention are:

[0015] 1. The present invention uses alkali solution or seawater to absorb the unorganized flue gas emitted by the electrolysis workshop. The main process is: absorption liquid preparation, pressurization, adsorption, collection, etc., which effectively treats the pollutants in the unorganized flue gas emitted by the electrolysis workshop, and the purification efficiency can reach more than 95%;

[0016] 2. The present invention adopts alkaline preparation liquid, which has little corrosiveness to the skylight and equipment operation and is safe to use;

[0017] 3. The droplets generated by the spray nozzle of the present invention have small volatilization and drifting amount, and the pollutants can be efficiently recovered;

[0018] 4. The absorption liquid in the present invention can be circulated and sprayed, the amount used is small, it does not affect the waterproofness of the ventilator, and has the functions of flow regulation and flow interruption monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the flue gas purification system of the present invention;

[0020] Figure 2 Schematic diagram of the spraying process of the present invention (side view of the skylight, where α is the spray angle of the nozzle);

[0021] Figure 3 Schematic diagram of the spraying state of the nozzle of the present invention (where α is the spray angle of the nozzle);

[0022] in,

[0023] 1-mixing tank, 2-water pump, 3-water inlet main pipe, 4-sprinkler, 5-ventilator, 6-main control valve, 7-drainage tank, 8-drainage riser, 9-drainage horizontal pipe, 10-branch control valve, 11-45° inclined tee, 12-water inlet branch pipe. DETAILED DESCRIPTION

[0024] In order to better explain the present invention and facilitate understanding, the technical solutions and effects of the present invention are described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0025] Example 1

[0026] like Figure 1-3As shown, a purification system for unorganized flue gas emitted from a skylight in an electrolysis workshop comprises an absorption liquid, a preparation tank 1, a water inlet main pipe 3, a water inlet branch pipe 12, a spray device 4, a drainage riser 8, and a drainage transverse pipe 9. The absorption liquid is a sodium hydroxide solution or seawater with a mass concentration of 0.1 to 42%, which is stored in the preparation tank 1; the preparation tank 1 is used to store the prepared absorption liquid, and its material cannot react with the absorption liquid; the water inlet main pipe 3 is arranged on both sides of the skylight ventilator 5 of the electrolysis workshop, one end of which is connected to the preparation tank 1 through a water pump 2, and the other end is a closed port; a liquid level gauge is provided in the preparation tank 1, and the liquid level gauge and the water pump 2 are electrically connected to the control room of the electrolysis workshop, and the liquid level gauge sends an absorption liquid level signal to the control room of the electrolysis workshop. When the preset liquid level is reached, the control room of the electrolysis workshop controls the start and stop of the water pump 2; the water inlet branch pipe 12 is arranged on the water inlet main pipe 3 , which is connected to the water inlet main pipe 3, the spray device 4 is arranged at the end of the water inlet branch pipe 12, which is connected to the water inlet branch pipe 12, and the spray direction points to the skylight ventilator 5 of the electrolysis workshop. The absorption liquid is pumped from the mixing tank 1 to the spray device 4 through the water pump 2 and sprayed to the ventilator 5; a control main valve 6 is arranged on the water inlet main pipe 3 between the water pump 2 and the spray device 4, and a branch line control valve 10 is arranged on the water inlet branch pipe 12, which is electrically connected to the control room of the electrolysis workshop and is used for segmented maintenance of the spray device 4; the drainage horizontal pipe 9 is arranged parallel to the water inlet main pipe 3 on both sides of the skylight ventilator 5 of the electrolysis workshop, one end of which is connected to the mixing tank 1, and the other end is a closed port; the drainage riser 8 is arranged on the drainage horizontal pipe 9 through a 45° inclined tee 11, and the water inlet of the drainage riser 8 is connected to the drainage grooves 7 on both sides of the skylight ventilator 5 of the electrolysis workshop; the other end of the 45° inclined tee 11 is connected to the rainwater downpipe of the building body. The spray device 4 is a spray nozzle. In this embodiment, the spray angle of the spray nozzle is 10°, the particle size of the spray droplets is 0.1 mm, and the spray shape is fan-shaped, empty cone-shaped or filled cone-shaped, which neither affects the normal air discharge nor allows the droplets to fully contact with the flue gas.

[0027] A flow meter is provided on the water inlet branch pipe 12, and the flow meter is electrically connected to the control room of the electrolysis workshop and has a flow interruption monitoring function. When the flow meter detects that the flow on a certain water inlet branch pipe 12 is abnormal, the control room of the electrolysis workshop controls the branch line control valve 10 on the water inlet branch pipe 12 to close, thereby performing maintenance on the spray device 4, controlling the water flow rate and pressure of each nozzle, and ensuring that the sprayed absorption liquid is within a suitable particle size range and a reasonable liquid shape.

[0028] When it rains, the water pump 2 is turned off, and the control main valve 6 on the water inlet main pipe 3 is closed at the same time, the purification system is turned off, and the rainwater overflow is discharged through the rain down pipe, and the system is restarted after the rain stops.

[0029] The above-mentioned purification method of the purification system of the unorganized emission of flue gas from the skylight of the electrolysis workshop specifically comprises the following steps:

[0030] Step 1: Preparation: In this embodiment, sodium hydroxide solid or liquid alkali purchased from the market is used to prepare a sodium hydroxide solution with a mass concentration of 0.1% as the absorption liquid, which is stored in the preparation tank 1;

[0031] Step 2: Pressurization: The absorption liquid prepared in step 1 is pressurized by the water pump 2, and the absorption liquid is transported to the spray device 4 through the water inlet main pipe 3 and the water inlet branch pipe 12. The water pump 2 provides the necessary flow and pressure for the spray device 4;

[0032] Step 3: Purification: The pressurized absorption liquid in step 2 is sprayed out through the spray device 4 and fully contacts with the electrolytic flue gas discharged from the ventilator 5, so that the flue gas pollutants fully contact and react with the absorption liquid to purify the soluble substances in the flue gas. The principle is as follows:

[0033] NaOH+HF→NaF+H2O

[0034] 2NaOH+SO2→Na2SO3+H2O;

[0035] Step 4: Collection: The absorption liquid that is in full contact with the electrolytic flue gas in step 3 is discharged along the rain shield in the ventilator 5, collected in the drainage trough 7 of the ventilator 5, flows along the drainage trough 7 to the drainage riser 8, flows through the drainage riser 8 to the drainage cross pipe 9, and finally flows back to the mixing tank 1. The absorption liquid is recycled until the absorption liquid is saturated, and then the impurities, fluorine, sulfur and calcium removal treatments are carried out. The impurities, fluorine, sulfur and calcium removal treatments are carried out by the method disclosed in the Chinese patent (application number: 201710484585.2, publication date: October 17, 2017).

[0036] Example 2

[0037] like Figure 1-3As shown, a purification system for unorganized flue gas emitted from a skylight in an electrolysis workshop comprises an absorption liquid, a preparation tank 1, a water inlet main pipe 3, a water inlet branch pipe 12, a spray device 4, a drainage riser 8, and a drainage transverse pipe 9. The absorption liquid is a sodium hydroxide solution or seawater with a mass concentration of 0.1 to 42%, which is stored in the preparation tank 1; the preparation tank 1 is used to store the prepared absorption liquid, and its material cannot react with the absorption liquid; the water inlet main pipe 3 is arranged on both sides of the skylight ventilator 5 of the electrolysis workshop, one end of which is connected to the preparation tank 1 through a water pump 2, and the other end is a closed port; a liquid level gauge is provided in the preparation tank 1, and the liquid level gauge and the water pump 2 are electrically connected to the control room of the electrolysis workshop, and the liquid level gauge sends an absorption liquid level signal to the control room of the electrolysis workshop. When the preset liquid level is reached, the control room of the electrolysis workshop controls the start and stop of the water pump 2; the water inlet branch pipe 12 is arranged on the water inlet main pipe 3 , which is connected to the water inlet main pipe 3, the spray device 4 is arranged at the end of the water inlet branch pipe 12, which is connected to the water inlet branch pipe 12, and the spray direction points to the skylight ventilator 5 of the electrolysis workshop. The absorption liquid is pumped from the mixing tank 1 to the spray device 4 through the water pump 2 and sprayed to the ventilator 5; a control main valve 6 is arranged on the water inlet main pipe 3 between the water pump 2 and the spray device 4, and a branch line control valve 10 is arranged on the water inlet branch pipe 12, which is electrically connected to the control room of the electrolysis workshop and is used for segmented maintenance of the spray device 4; the drainage horizontal pipe 9 is arranged parallel to the water inlet main pipe 3 on both sides of the skylight ventilator 5 of the electrolysis workshop, one end of which is connected to the mixing tank 1, and the other end is a closed port; the drainage riser 8 is arranged on the drainage horizontal pipe 9 through a 45° inclined tee 11, and the water inlet of the drainage riser 8 is connected to the drainage grooves 7 on both sides of the skylight ventilator 5 of the electrolysis workshop; the other end of the 45° inclined tee 11 is connected to the rainwater downpipe of the building body. The spray device 4 is a spray nozzle. In this embodiment, the spray angle of the spray nozzle is 50°, the particle size of the spray droplets is 0.4 mm, and the spray shape is fan-shaped, empty cone-shaped or filled cone-shaped, which neither affects the normal air discharge nor allows the droplets to fully contact with the flue gas.

[0038] A flow meter is provided on the water inlet branch pipe 12, and the flow meter is electrically connected to the control room of the electrolysis workshop and has a flow interruption monitoring function. When the flow meter detects that the flow on a certain water inlet branch pipe 12 is abnormal, the control room of the electrolysis workshop controls the branch line control valve 10 on the water inlet branch pipe 12 to close, thereby performing maintenance on the spray device 4, controlling the water flow rate and pressure of each nozzle, and ensuring that the sprayed absorption liquid is within a suitable particle size range and a reasonable liquid shape.

[0039] When it rains, the water pump 2 is turned off, and the control main valve 6 on the water inlet main pipe 3 is closed at the same time, the purification system is turned off, and the rainwater overflow is discharged through the rain down pipe, and the system is restarted after the rain stops.

[0040] The above-mentioned purification method of the purification system of the unorganized emission of flue gas from the skylight of the electrolysis workshop specifically comprises the following steps:

[0041] Step 1: Preparation: In this embodiment, sodium hydroxide solid or liquid alkali purchased from the market is used to prepare a sodium hydroxide solution with a mass concentration of 1% as the absorption liquid, which is stored in the preparation tank 1;

[0042] Step 2: Pressurization: The absorption liquid prepared in step 1 is pressurized by the water pump 2, and the absorption liquid is transported to the spray device 4 through the water inlet main pipe 3 and the water inlet branch pipe 12. The water pump 2 provides the necessary flow and pressure for the spray device 4;

[0043] Step 3: Purification: The pressurized absorption liquid in step 2 is sprayed out through the spray device 4 and fully contacts with the electrolytic flue gas discharged from the ventilator 5, so that the flue gas pollutants fully contact and react with the absorption liquid to purify the soluble substances in the flue gas. The principle is as follows:

[0044] NaOH+HF→NaF+H2O

[0045] 2NaOH+SO2→Na2SO3+H2O;

[0046] Step 4: Collection: The absorption liquid that is in full contact with the electrolytic flue gas in step 3 is discharged along the rain shield in the ventilator 5, collected in the drainage trough 7 of the ventilator 5, flows along the drainage trough 7 to the drainage riser 8, flows through the drainage riser 8 to the drainage cross pipe 9, and finally flows back to the mixing tank 1. The absorption liquid is recycled until the absorption liquid is saturated, and then the impurities, fluorine, sulfur and calcium removal treatments are carried out. The impurities, fluorine, sulfur and calcium removal treatments are carried out by the method disclosed in the Chinese patent (application number: 201710484585.2, publication date: October 17, 2017).

[0047] Example 3

[0048] like Figure 1-3As shown, a purification system for unorganized flue gas emitted from a skylight in an electrolysis workshop comprises an absorption liquid, a preparation tank 1, a water inlet main pipe 3, a water inlet branch pipe 12, a spray device 4, a drainage riser 8, and a drainage transverse pipe 9. The absorption liquid is a sodium hydroxide solution or seawater with a mass concentration of 0.1 to 42%, which is stored in the preparation tank 1; the preparation tank 1 is used to store the prepared absorption liquid, and its material cannot react with the absorption liquid; the water inlet main pipe 3 is arranged on both sides of the skylight ventilator 5 of the electrolysis workshop, one end of which is connected to the preparation tank 1 through a water pump 2, and the other end is a closed port; a liquid level gauge is provided in the preparation tank 1, and the liquid level gauge and the water pump 2 are electrically connected to the control room of the electrolysis workshop, and the liquid level gauge sends an absorption liquid level signal to the control room of the electrolysis workshop. When the preset liquid level is reached, the control room of the electrolysis workshop controls the start and stop of the water pump 2; the water inlet branch pipe 12 is arranged on the water inlet main pipe 3 , which is connected to the water inlet main pipe 3, the spray device 4 is arranged at the end of the water inlet branch pipe 12, which is connected to the water inlet branch pipe 12, and the spray direction points to the skylight ventilator 5 of the electrolysis workshop. The absorption liquid is pumped from the mixing tank 1 to the spray device 4 through the water pump 2 and sprayed to the ventilator 5; a control main valve 6 is arranged on the water inlet main pipe 3 between the water pump 2 and the spray device 4, and a branch line control valve 10 is arranged on the water inlet branch pipe 12, which is electrically connected to the control room of the electrolysis workshop and is used for segmented maintenance of the spray device 4; the drainage horizontal pipe 9 is arranged parallel to the water inlet main pipe 3 on both sides of the skylight ventilator 5 of the electrolysis workshop, one end of which is connected to the mixing tank 1, and the other end is a closed port; the drainage riser 8 is arranged on the drainage horizontal pipe 9 through a 45° inclined tee 11, and the water inlet of the drainage riser 8 is connected to the drainage grooves 7 on both sides of the skylight ventilator 5 of the electrolysis workshop; the other end of the 45° inclined tee 11 is connected to the rainwater downpipe of the building body. The spray device 4 is a spray nozzle. In this embodiment, the spray angle of the spray nozzle is 100°, the particle size of the spray droplets is 0.7 mm, and the spray shape is fan-shaped, empty cone-shaped or filled cone-shaped, which neither affects the normal air discharge nor allows the droplets to fully contact with the flue gas.

[0049] A flow meter is provided on the water inlet branch pipe 12, and the flow meter is electrically connected to the control room of the electrolysis workshop and has a flow interruption monitoring function. When the flow meter detects that the flow on a certain water inlet branch pipe 12 is abnormal, the control room of the electrolysis workshop controls the branch line control valve 10 on the water inlet branch pipe 12 to close, thereby performing maintenance on the spray device 4, controlling the water flow rate and pressure of each nozzle, and ensuring that the sprayed absorption liquid is within a suitable particle size range and a reasonable liquid shape.

[0050] When it rains, the water pump 2 is turned off, and the control main valve 6 on the water inlet main pipe 3 is closed at the same time, the purification system is turned off, and the rainwater overflow is discharged through the rain down pipe, and the system is restarted after the rain stops.

[0051] The above-mentioned purification method of the purification system of the unorganized emission of flue gas from the skylight of the electrolysis workshop specifically comprises the following steps:

[0052] Step 1: Preparation: In this embodiment, sodium hydroxide solid or liquid alkali purchased from the market is used to prepare a sodium hydroxide solution with a mass concentration of 38% as the absorption liquid, which is stored in the preparation tank 1;

[0053] Step 2: Pressurization: The absorption liquid prepared in step 1 is pressurized by the water pump 2, and the absorption liquid is transported to the spray device 4 through the water inlet main pipe 3 and the water inlet branch pipe 12. The water pump 2 provides the necessary flow and pressure for the spray device 4;

[0054] Step 3: Purification: The pressurized absorption liquid in step 2 is sprayed out through the spray device 4 and fully contacts with the electrolytic flue gas discharged from the ventilator 5, so that the flue gas pollutants fully contact and react with the absorption liquid to purify the soluble substances in the flue gas. The principle is as follows:

[0055] NaOH+HF→NaF+H2O

[0056] 2NaOH+SO2→Na2SO3+H2O;

[0057] Step 4: Collection: The absorption liquid that is in full contact with the electrolytic flue gas in step 3 is discharged along the rain shield in the ventilator 5, collected in the drainage trough 7 of the ventilator 5, flows along the drainage trough 7 to the drainage riser 8, flows through the drainage riser 8 to the drainage cross pipe 9, and finally flows back to the mixing tank 1. The absorption liquid is recycled until the absorption liquid is saturated, and then the impurities, fluorine, sulfur and calcium removal treatments are carried out. The impurities, fluorine, sulfur and calcium removal treatments are carried out by the method disclosed in the Chinese patent (application number: 201710484585.2, publication date: October 17, 2017).

[0058] Example 4

[0059] like Figure 1-3As shown, a purification system for unorganized flue gas emitted from a skylight in an electrolysis workshop comprises an absorption liquid, a preparation tank 1, a water inlet main pipe 3, a water inlet branch pipe 12, a spray device 4, a drainage riser 8, and a drainage transverse pipe 9. The absorption liquid is a sodium hydroxide solution or seawater with a mass concentration of 0.1 to 42%, which is stored in the preparation tank 1; the preparation tank 1 is used to store the prepared absorption liquid, and its material cannot react with the absorption liquid; the water inlet main pipe 3 is arranged on both sides of the skylight ventilator 5 of the electrolysis workshop, one end of which is connected to the preparation tank 1 through a water pump 2, and the other end is a closed port; a liquid level gauge is provided in the preparation tank 1, and the liquid level gauge and the water pump 2 are electrically connected to the control room of the electrolysis workshop, and the liquid level gauge sends an absorption liquid level signal to the control room of the electrolysis workshop. When the preset liquid level is reached, the control room of the electrolysis workshop controls the start and stop of the water pump 2; the water inlet branch pipe 12 is arranged on the water inlet main pipe 3 , which is connected to the water inlet main pipe 3, the spray device 4 is arranged at the end of the water inlet branch pipe 12, which is connected to the water inlet branch pipe 12, and the spray direction points to the skylight ventilator 5 of the electrolysis workshop. The absorption liquid is pumped from the mixing tank 1 to the spray device 4 through the water pump 2 and sprayed to the ventilator 5; a control main valve 6 is arranged on the water inlet main pipe 3 between the water pump 2 and the spray device 4, and a branch line control valve 10 is arranged on the water inlet branch pipe 12, which is electrically connected to the control room of the electrolysis workshop and is used for segmented maintenance of the spray device 4; the drainage horizontal pipe 9 is arranged parallel to the water inlet main pipe 3 on both sides of the skylight ventilator 5 of the electrolysis workshop, one end of which is connected to the mixing tank 1, and the other end is a closed port; the drainage riser 8 is arranged on the drainage horizontal pipe 9 through a 45° inclined tee 11, and the water inlet of the drainage riser 8 is connected to the drainage grooves 7 on both sides of the skylight ventilator 5 of the electrolysis workshop; the other end of the 45° inclined tee 11 is connected to the rainwater downpipe of the building body. The spray device 4 is a spray nozzle. In this embodiment, the spray angle of the spray nozzle is 135°, the spray droplet diameter is 1 mm, and the spray shape is fan-shaped, empty cone-shaped or filled cone-shaped, which neither affects the normal air discharge nor allows the droplets to fully contact with the flue gas.

[0060] A flow meter is provided on the water inlet branch pipe 12, and the flow meter is electrically connected to the control room of the electrolysis workshop and has a flow interruption monitoring function. When the flow meter detects that the flow on a certain water inlet branch pipe 12 is abnormal, the control room of the electrolysis workshop controls the branch line control valve 10 on the water inlet branch pipe 12 to close, thereby performing maintenance on the spray device 4, controlling the water flow rate and pressure of each nozzle, and ensuring that the sprayed absorption liquid is within a suitable particle size range and a reasonable liquid shape.

[0061] When it rains, the water pump 2 is turned off, and the control main valve 6 on the water inlet main pipe 3 is closed at the same time, the purification system is turned off, and the rainwater overflow is discharged through the rain down pipe, and the system is restarted after the rain stops.

[0062] The above-mentioned purification method of the purification system of the unorganized emission of flue gas from the skylight of the electrolysis workshop specifically comprises the following steps:

[0063] Step 1: Preparation: In this embodiment, seawater is used as the absorption liquid and stored in the preparation tank 1;

[0064] Step 2: Pressurization: The absorption liquid prepared in step 1 is pressurized by the water pump 2, and the absorption liquid is transported to the spray device 4 through the water inlet main pipe 3 and the water inlet branch pipe 12. The water pump 2 provides the necessary flow and pressure for the spray device 4;

[0065] Step 3: Purification: The pressurized absorption liquid in step 2 is sprayed out through the spray device 4 and fully contacts with the electrolytic flue gas discharged from the ventilator 5, so that the flue gas pollutants fully contact and react with the absorption liquid to purify the soluble substances in the flue gas. The principle is as follows:

[0066] NaOH+HF→NaF+H2O

[0067] 2NaOH+SO2→Na2SO3+H2O;

[0068] Step 4: Collection: The absorption liquid that is in full contact with the electrolytic flue gas in step 3 is discharged along the rain shield in the ventilator 5, collected in the drainage trough 7 of the ventilator 5, flows along the drainage trough 7 to the drainage riser 8, flows through the drainage riser 8 to the drainage cross pipe 9, and finally flows back to the mixing tank 1. The absorption liquid is recycled until the absorption liquid is saturated, and then the impurities, fluorine, sulfur and calcium removal treatments are carried out. The impurities, fluorine, sulfur and calcium removal treatments are carried out by the method disclosed in the Chinese patent (application number: 201710484585.2, publication date: October 17, 2017).

Claims

1. A purification method for a purification system of unorganized flue gas emitted from a skylight in an electrolysis workshop, characterized in that: A purification system for unorganized flue gas emitted from a skylight in an electrolysis workshop is adopted, comprising an absorption liquid, a mixing tank, a water inlet main pipe, a water inlet branch pipe, a spray device, a drainage riser pipe, and a drainage cross pipe, wherein the absorption liquid is a sodium hydroxide solution or seawater with a mass concentration of 0.1-42%, which is stored in the mixing tank; the water inlet main pipe is arranged on both sides of the skylight ventilator in the electrolysis workshop, one end of which is connected to the mixing tank through a water pump, and the other end is a closed port; a liquid level gauge is arranged in the mixing tank, and the liquid level gauge and the water pump are electrically connected to a control room in the electrolysis workshop; the water inlet branch pipe is arranged on the water inlet main pipe and communicates with the water inlet main pipe, and the spray device is arranged at the end of the water inlet branch pipe and is connected to the water inlet branch pipe The spray direction points to the skylight ventilator in the electrolysis workshop; a control main valve is arranged on the water inlet main pipe between the water pump and the spray device, and a branch line control valve is arranged on the water inlet branch pipe, which is electrically connected to the control room of the electrolysis workshop; a flow meter is arranged on the water inlet branch pipe, and the flow meter is electrically connected to the control room of the electrolysis workshop; the drainage horizontal pipe is arranged on both sides of the skylight ventilator in the electrolysis workshop in parallel with the water inlet main pipe, one end is connected to the mixing tank, and the other end is a closed port; the drainage riser is arranged on the drainage horizontal pipe through a 45° inclined tee, and the water inlet of the drainage riser is connected to the drainage grooves on both sides of the skylight ventilator in the electrolysis workshop; the other end of the 45° inclined tee is connected to the rainwater downpipe of the building body; The spray device is a spray nozzle, the spray angle of the spray nozzle is 10°~135°, the spray droplet diameter is 0.1~1mm, and the spray shape is fan-shaped, empty cone or filled cone; The purification method includes the following steps: Step 1: Preparation: Prepare sodium hydroxide solution or seawater with a mass concentration of 0.1~42% as the absorption liquid and store it in the preparation tank; Step 2: Pressurization: The absorption liquid in step 1 is pressurized by a water pump, and the absorption liquid is transported to the spraying device through the water inlet main pipe and the water inlet branch pipe; Step 3: Purification: The pressurized absorption liquid in step 2 is sprayed out through the spray device and fully contacts with the electrolytic flue gas discharged from the ventilator, so that the flue gas pollutants fully contact and react with the absorption liquid to purify the soluble substances in the flue gas. The principle is as follows: NaOH+HF→NaF+ H2O 2NaOH+SO2→Na2SO3+ H2O; Step 4: Collection: The absorption liquid that has been in full contact with the electrolytic flue gas in step 3 is discharged along the rain shield in the ventilator, collected in the drainage trough of the ventilator, flows along the drainage trough to the drainage riser, flows through the drainage riser to the drainage cross pipe, and finally flows back to the mixing tank. The absorption liquid is recycled until it is saturated, and then it is treated with impurity removal, fluorine removal, sulfur removal, and calcium removal.

2. The purification method of a purification system for unorganized flue gas emission from a skylight in an electrolysis workshop according to claim 1, characterized in that: The material of the mixing tank cannot react with the absorption liquid.

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