Tail gas emission treatment device in ferric trichloride production

Abstract

The invention discloses a tail gas emission treatment device in ferric trichloride production, which comprises an oxidation reaction kettle, and an oxygen tank, a waste acid tank, a hydrochloric acid tank and a catalyst tank are connected to the oxidation reaction kettle through pipelines so as to provide reaction raw materials for the oxidation reaction kettle. The tail gas output end of the oxidation reaction kettle is sequentially connected with a first tail gas absorption tower and a second tail gas absorption tower, the first tail gas absorption tower and the second tail gas absorption tower are connected through a pipeline, and the rear end of the first tail gas absorption tower is connected in series with a first tail gas spray tower through a pipeline; pipelines are arranged on the first tail gas absorption tower, the first tail gas spray tower, the second tail gas absorption tower and the second tail gas spray tower and are connected with an alkali liquor tank, and a sodium hydroxide alkaline solution is supplied through the alkali liquor tank; the tail gas of ferric trichloride production is absorbed and treated by using alkali liquor, and the generated waste liquid can be recycled after being evaporated and concentrated. A PH meter is additionally arranged in the tail gas absorption device, signals are transmitted to a data control center, and the concentration of alkali liquor is automatically adjusted according to the PH value.

Description

Technical Field

[0001] The invention relates to the technical field of tail gas treatment devices, and in particular to a tail gas emission treatment device in ferric chloride production. Background Art

[0002] Ferrous chloride is produced by using waste acid from cold rolling of steel. The waste acid is pumped into the oxidation reactor. Under the action of the catalyst sodium nitrite, pure oxygen is introduced. After the exothermic oxidation reaction, ferrous chloride is oxidized to ferric chloride. Ferrous chloride is produced by oxygen oxidation method. Reaction equation: However, the sodium nitrite catalyst added in the production process brings a certain concentration of nitrogen oxides into the exhaust gas during the exhaust gas emission process. The original design of the exhaust gas absorption treatment device uses urea as an absorption liquid to absorb nitrogen oxides, and the exhaust gas detection nitrogen oxides exceed the standard; urea as an absorption liquid cannot absorb the chloride ions in the ferric chloride preparation device, and a large amount of chloride ions are discharged, and the environmental protection emissions of nitrogen oxides and chloride ions in the exhaust gas do not meet the standards. In order to solve the above technical problems, it is urgent to provide a tail gas emission control device in the production of ferric chloride. Summary of the invention

[0003] To solve the above technical problems, the technical solution provided by the present invention is as follows: a device for treating tail gas emission in the production of ferric chloride, comprising an oxidation reactor, on which an oxygen tank, a waste acid tank, a hydrochloric acid tank and a catalyst tank are connected through pipelines to provide reaction raw materials to the oxidation reactor, and a tail gas output end of the oxidation reactor is sequentially connected to a first tail gas absorption tower and a second tail gas absorption tower, the first tail gas absorption tower and the second tail gas absorption tower are connected through a pipeline, a first tail gas spray tower is connected in series at the rear end of the first tail gas absorption tower through a pipeline, a second tail gas spray tower is connected in series at the rear end of the second tail gas absorption tower through a pipeline, the first tail gas absorption tower, the first tail gas spray tower, the second tail gas absorption tower and the second tail gas spray tower are all provided with pipelines connected to an alkali liquid tank, and a sodium hydroxide alkaline solution is supplied through the alkali liquid tank;

[0004] An online exhaust gas inspection device is connected in front of the exhaust gas emission pipeline at the rear end of the second exhaust gas spray tower. The online exhaust gas inspection device includes nitrogen oxide and chloride ion detectors. The detection data of the nitrogen oxide and chloride ion detectors are uploaded to the data control center through a data transmission module to realize remote data transmission.

[0005] Furthermore, four groups of pH meters are provided, one group of pH meters is installed in the first exhaust gas absorption tower and the first exhaust gas spray tower, one group of pH meters is installed in the second exhaust gas absorption tower and the second exhaust gas spray tower, and liquid level detectors are installed inside the first exhaust gas absorption tower, the second exhaust gas spray tower, the second exhaust gas absorption tower, and the second exhaust gas spray tower.

[0006] Furthermore, a regulating valve is installed on the exhaust pipe of the oxidation reactor, and the regulating valve is interlocked with the tail gas absorption pump.

[0007] The advantages of the invention compared with the prior art are:

[0008] The present invention uses sodium hydroxide lye to replace urea to absorb and treat the tail gas produced by ferric chloride, and has good absorption effect and the tail gas emission meets the standard. A PH acidity meter is installed in the tail gas absorption device to transmit the signal to the data control center, and the lye concentration is automatically adjusted according to the acidity PH value. Each tank is equipped with a liquid level meter to facilitate the timely addition of alkaline absorption liquid.

[0009] In the present invention, the waste liquid formed after the tail gas is absorbed by the alkali liquid is stored in the dilute acid water tank, and the waste liquid dilute acid water is evaporated and concentrated in the evaporation concentration tank and then returned to the waste acid tank, thereby achieving zero discharge of waste acid and waste liquid, allowing the waste acid liquid to be recycled, and reducing the use cost of the entire device.

[0010] The present invention connects an online tail gas inspection device to the tail end of the spray tower after the second tail gas absorption tower. The specific detection data include nitrogen oxide and chloride ion data, which can timely monitor the indicators of the tail gas after absorption, so that the exhaust gas can be discharged smoothly after being absorbed and neutralized. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic structural diagram of a device for treating tail gas emissions in the production of ferric chloride according to the present invention;

[0012] Figure 2 is a structural schematic diagram of the first tail gas spray tower;

[0013] Figure 3 Another structural diagram of the first tail gas spray tower

[0014] Among them, 1. oxidation reactor, 2. oxygen tank, 3. waste acid tank, 4. hydrochloric acid tank, 5. first tail gas absorption tower, 6. second tail gas absorption tower, 7. first tail gas spray tower, 8. second tail gas spray tower, 9. alkali liquid tank, 10. dilute acid water tank, 11. evaporation concentration tank, 12. catalyst tank, 13. partition, 14. spray chamber, 15. central pipeline, 16. branch pipeline, 17. spray head. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0016] The present invention is described in detail with reference to the accompanying drawings.

[0017] The present invention provides a tail gas emission control device in the production of ferric chloride during specific implementation, comprising an oxidation reactor 1, on which an oxygen tank 2, a waste acid tank 3, a hydrochloric acid tank 4 and a catalyst tank 12 are connected through pipelines to provide reaction raw materials to the oxidation reactor 1, characterized in that: the tail gas output end of the oxidation reactor 1 is sequentially connected to a first tail gas absorption tower 5 and a second tail gas absorption tower 6, the first tail gas absorption tower 5 and the second tail gas absorption tower 6 are connected through a pipeline, a first tail gas spray tower 7 is connected in series at the rear end of the first tail gas absorption tower 5 through a pipeline, a second tail gas spray tower 8 is connected in series at the rear end of the second tail gas absorption tower 6 through a pipeline, the first tail gas absorption tower 5, the first tail gas spray tower 7, the second tail gas absorption tower 6, and the second tail gas spray tower 8 are all provided with pipelines connected to an alkali liquid tank 9, and a sodium hydroxide alkaline solution is supplied through the alkali liquid tank 9; the tail gas is absorbed by the alkali liquid sodium hydroxide, and the specific reaction equation is as follows:

[0018] NaOH+HCL=NaCL+H2O

[0019] 2NaOH+3NO2=2NaNO3+NO+H2O

[0020] 2NaOH+NO2+NO=2NaNO2+H2O

[0021] The exhaust gas emission front end of the second exhaust gas spray tower 8 is connected to an online exhaust gas inspection device, which includes a nitrogen oxide detector and a chloride ion detector. The detection data of the nitrogen oxide and chloride ion detectors are uploaded to the data control center through a data transmission module to realize remote data transmission and process control.

[0022] Embodiment 1:

[0023] In the specific operation of the present invention, alkali liquor is used as an absorption liquid, and waste acid from cold rolling of steel is used to produce ferric chloride. The oxygen tank 2, the waste acid tank 3, the hydrochloric acid tank 4 and the catalyst tank 12 are used to be connected with the oxidation reactor 1, and the reaction equation is as follows:

[0024]

[0025] The gases generated during the production of ferric chloride include: chlorine, nitrogen oxides, and ferric chloride flue gas. After the above gases are condensed by the condenser, part of the gases settle in the storage tank, and the other part of the gases overflow. The chlorine in the overflowed mixed tail gas and the chlorine in the ferric chloride flue gas fully contact with the water in the air and generate strong heat to produce hydrogen chloride gas. After this part of the gas enters the first tail gas absorption tower 5 and the first tail gas spray tower 7 through the pipeline, it reacts with the alkaline absorption liquid in the first tail gas absorption tower 5 and the first tail gas spray tower 7. At this time, there will still be a part of the gas overflow. This part of the gas includes chlorine, nitrogen oxides, etc., which enter the second tail gas absorption tower 6 and the second tail gas spray tower 8 through the pipeline connecting the first tail gas absorption tower 5 and the first tail gas spray tower 7 to the second tail gas absorption tower 6. At this time, the chlorine and nitrogen oxides in this part of the gas tail gas are fully absorbed by the alkaline sodium hydroxide solution in the tail gas absorption device. Finally, the tail gas passes through the online tail gas inspection device connected to the rear end of the pipeline of the second tail gas spray tower 8 to realize online detection of various indicators in the tail gas, and is discharged after passing the test.

[0026] In addition to achieving qualified tail gas discharge, the present invention comprises an oxidation reactor 1, a first tail gas absorption tower 5, a first tail gas spray tower 7, a second tail gas absorption tower 6, a second tail gas spray tower 8, a dilute acid water tank 10, an evaporation concentration tank 11 and a waste acid pipe 3 to form a circulation loop, wherein the waste liquid formed after the tail gas is absorbed by the alkali solution - dilute acid water is stored in the dilute acid water tank, and the dilute acid water is evaporated and concentrated in the evaporation concentration tank and then returned to the waste acid tank 3, and the sodium nitrite in the waste acid liquid can be circulated and used as a reaction catalyst, thereby achieving zero discharge of waste acid and waste liquid. The waste acid liquid is recycled, which not only reduces the use cost of the entire device but also is safe and environmentally friendly.

[0027] Among them, the tail end of the second exhaust gas spray tower 8 is connected to an online exhaust gas inspection device, which includes a nitrogen oxide and chloride ion detector. The detection data of the nitrogen oxide and chloride ion detector is uploaded to the data control center through a data transmission module to realize remote data transmission.

[0028] Specifically, four groups of pH meters are provided, one group of pH meters is installed in the first exhaust gas absorption tower 5 and the first exhaust gas spray tower 7, one group of pH meters is installed in the second exhaust gas absorption tower 6 and the second exhaust gas spray tower 8, and liquid level detectors are installed inside the first exhaust gas absorption tower 5, the second exhaust gas spray tower 7, the second exhaust gas absorption tower 6, and the second exhaust gas spray tower 8.

[0029] A regulating valve is installed on the exhaust pipe of the oxidation reactor 1 to form an interlock with the exhaust absorption pump. The function of the regulating valve is: when the oxidation reactor 1 is emptied, the valve opening can be controlled according to the rising speed of nitrogen oxides NOX in the exhaust gas detection emission to control the reactor to empty the operation; quick opening valve: when the oxygen reactor 1 is under pressure or in an emergency, the quick opening valve can be used to quickly empty the reactor

[0030] When the pH of the alkaline solution in the first tail gas absorption tower 5, the first tail gas spray tower 7 and the second tail gas absorption tower 6, the second tail gas spray tower 8 is ≤10, start replacing the absorption liquid, the tail gas absorption pump is interlocked with the exhaust valve of the oxidation reactor 1, start the tail gas absorption pump when the nitrogen oxide NOX is ≥10, and stop the tail gas absorption pump when NOX is ≤6.

[0031] Dilute acid water tank 10: Replace the magnetic flap level gauge with a radar level gauge and upload the signal. Add absorption liquid by remotely observing the level of dilute acid water in real time to avoid unqualified discharge and prevent leakage due to excessive level.

[0032] The present invention installs liquid level detectors in an oxidation reaction kettle 1, an oxygen tank 2, a waste acid tank 3, a hydrochloric acid tank 4, a catalyst tank 12, a first tail gas absorption tower 5, a second tail gas absorption tower 6, a first tail gas spray tower 7, a second tail gas spray tower 8, a dilute acid water tank 10 and an evaporation concentration tank 11 for liquid level detection. The detected liquid level data information is uploaded to a data control center through a data transmission module to realize remote data transmission.

[0033] Embodiment 2:

[0034] The second tail gas absorption tower 6 is provided with an alarm device, which includes a warning light and a voice prompter. The warning light and voice prompter are used for data transmission with the data control center through a network module. When the pH value, nitrogen oxide and chloride ion values, and liquid level values ​​are abnormal, the data control center controls the warning light to light up and controls the voice prompter to start the voice reminder function. An electromagnetic control valve is provided on the tail gas outlet pipe at the tail end of the second tail gas absorption tower 6, and the electromagnetic control valve is controlled to be opened or closed by the data control center.

[0035] When the present invention is working, the pH value, nitrogen oxide value and liquid level data are detected by the pH meter, nitrogen oxide and chloride ion detector and liquid level detector, and the detected data are transmitted to the data control center, and the data control center timely analyzes and processes the collected data. When the above data are abnormal, the data control center controls the corresponding alarm device to sound an alarm. At this time, the warning light starts to light up, and the voice prompter sends a voice alarm message to remind that the relevant detection data are abnormal, and the staff is reminded in time. At the same time, when the detection data is abnormal and the exhaust gas components do not meet the standards, the data control center controls the electromagnetic control valve to close and stop the exhaust gas emission.

[0036] Embodiment three:

[0037] The first tail gas spray tower 7 and the second tail gas spray tower 8 have the same structure. A plurality of baffles 13 are arranged in the first tail gas spray tower 7. The first tail gas spray tower 7 and the plurality of baffles 13 form a plurality of spray cavities 14. A plurality of spray assemblies 15 are arranged inside the spray cavities 14. Each spray cavity 14 on the first tail gas spray tower 7 is connected to the first tail gas absorption tower 5 through a pipeline. Each spray cavity 14 on the first tail gas absorption tower 5 is connected to the second tail gas absorption tower 6 through a pipeline. The spray assembly includes a central pipeline 15, a plurality of branch pipelines 16 and a spray head 17. The branch pipeline 16 is provided with four groups. The end of each branch pipeline 16 is connected to the spray head 17. The central pipeline 15 is rotatably connected to the first tail gas spray tower 7. The spray head 17 is arranged in a bowl-shaped structure for uniform spraying in the spray tower.

[0038] When the present invention is working, the exhaust gas passes through the first exhaust gas absorption tower 5 and then enters the first exhaust gas spray tower 7. Since a plurality of partitions 13 are arranged in the first exhaust gas spray tower 7, the exhaust gas is divided into a plurality of parts and enters a plurality of spray chambers 14. The central pipe 15 in the spray chamber 14 rotates to drive a plurality of branch pipes 16 and a spray head 17 to rotate accordingly, and spraying is started through the spray head 17. Spraying the exhaust gas by the rotating spray head 17 improves the purification efficiency of the exhaust gas. The above structure can realize spraying while rotating, increase the uniformity in the exhaust gas spraying process, and improve the spraying efficiency of the entire spraying device. The above structure can realize multiple spraying of the exhaust gas.

[0039] As a further elaboration of the present invention, a regulating valve is installed on the exhaust pipe of the oxidation reaction kettle 1, and the regulating valve is interlocked with the tail gas absorption pump.

[0040] As a further elaboration of the present invention, the second tail gas spray tower 8 is connected to a dilute acid water tank 10, and the liquid level detector is a radar level gauge installed in the dilute acid water tank 10 for real-time remote observation of the liquid level of the dilute acid water in the dilute acid water tank.

[0041] As a further explanation of the present invention, the rear portion of the dilute acid water tank 10 is connected to an evaporation concentration tank 11 , and the evaporation concentration tank 11 is used to form a circulation connection with the waste acid tank 3 through a pipeline.

[0042] As can be seen from the accompanying drawings, the rear part of the dilute acid water tank 10 is connected to an evaporation concentration tank 11, and the evaporation concentration tank 11 forms a circulation loop with the oxidation reactor 1 through the waste acid tank 3. Liquid level detectors are installed inside the dilute acid water tank 10 and the evaporation concentration tank 11 to achieve zero discharge of waste acid and waste liquid, so that the waste acid liquid can be recycled, reducing the use cost of the entire device.

[0043] As a further illustration of the present invention, the catalyst in the catalyst tank 12 is sodium nitrite.

[0044] The present invention and its embodiments are described above, and such description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A device for treating tail gas emission in the production of ferric chloride, comprising an oxidation reactor (1), an oxygen tank (2), a waste acid tank (3), a hydrochloric acid tank (4) and a catalyst tank (12) being connected to the oxidation reactor (1) through a pipeline, so as to provide reaction raw materials to the oxidation reactor (1), characterized in that: The tail gas output end of the oxidation reaction kettle (1) is connected in sequence to a first tail gas absorption tower (5) and a second tail gas absorption tower (6); the first tail gas absorption tower (5) and the second tail gas absorption tower (6) are connected via a pipeline; a first tail gas spray tower (7) is connected in series at the rear end of the first tail gas absorption tower (5) via a pipeline; a second tail gas spray tower (8) is connected in series at the rear end of the second tail gas absorption tower (6) via a pipeline; the first tail gas absorption tower (5), the first tail gas spray tower (7), the second tail gas absorption tower (6), and the second tail gas spray tower (8) are all provided with pipelines connected to an alkali liquid tank (9); and a sodium hydroxide alkaline solution is supplied via the alkali liquid tank (9). An online exhaust gas detection device is connected to the front end of the exhaust gas discharge pipe at the rear end of the second exhaust gas spray tower (8), and the online exhaust gas detection device includes a nitrogen oxide and chloride ion detector. The detection data of the nitrogen oxide and chloride ion detector is uploaded to the data control center through a data transmission module to realize remote data transmission and monitoring.

2. A tail gas emission control device in the production of ferric chloride according to claim 1, characterized in that: Four groups of pH meters are provided, one group of pH meters is installed in each of the first tail gas absorption tower (5) and the first tail gas spray tower (7), and one group of pH meters is installed in each of the second tail gas absorption tower (6) and the second tail gas spray tower (8). Liquid level detectors are installed inside the first tail gas absorption tower (5), the second tail gas spray tower (7) and the second tail gas absorption tower (6), and the second tail gas spray tower (8).

3. A tail gas emission control device in the production of ferric chloride according to claim 1, characterized in that: A regulating valve is installed on the exhaust pipe of the oxidation reaction kettle (1), the regulating valve is interlocked with the tail gas absorption pump, and a liquid level detector is installed inside the regulating valve.

4. A tail gas emission control device in the production of ferric chloride according to claim 1, characterized in that: The second tail gas spray tower (8) is connected to a dilute acid water tank (10) at the rear, and the dilute acid water tank stores waste liquid after the tail gas is absorbed. A liquid level detector is installed inside the dilute acid water tank (10). The liquid level detector is a radar level gauge, which is installed in the dilute acid water tank (10) to remotely observe the liquid level of the dilute acid water in the tank in real time.

5. A tail gas emission control device in the production of ferric chloride according to claim 4, characterized in that: The dilute acid water tank (10) is connected to an evaporation concentration tank (11) at the rear, and the evaporation concentration tank (11) forms a circulation loop with the oxidation reaction kettle (1) through the waste acid tank (3). Liquid level detectors are installed inside the dilute acid water tank (10) and the evaporation concentration tank (11).

6. A tail gas emission control device in the production of ferric chloride according to claim 1, characterized in that: The oxidation reactor (1) is provided with a quick-opening valve. When the oxidation reactor (1) is under pressure or in an emergency, the quick-opening valve is used to quickly empty the oxidation reactor.

7. A device for treating tail gas emissions in the production of ferric chloride according to any one of claims 1 to 6, characterized in that: The catalyst in the catalyst tank (12) is sodium nitrite, and a liquid level detector is installed inside the catalyst tank (12).

8. A tail gas emission control device in the production of ferric chloride according to claim 1, characterized in that: The second tail gas absorption tower (6) is provided with an alarm device, the alarm device comprising a warning light and a voice prompter, the warning light and the voice prompter are used to transmit data with the data control center through a network module, when the pH value, nitrogen oxides, chloride ion value, and liquid level value are abnormal, the data control center controls the warning light to light up and controls the voice prompter to start the voice reminder function, and the tail end tail gas outlet pipe of the second tail gas spray tower (8) is provided with an electromagnetic control valve, and the electromagnetic control valve is controlled to be opened or closed by the data control center.

9. A tail gas emission control device in the production of ferric chloride according to claim 1, characterized in that: The first tail gas spray tower (7) and the second tail gas spray tower (8) have the same structure. A plurality of partitions (13) are arranged inside the first tail gas spray tower (7). The first tail gas spray tower (7) and the plurality of partitions (13) form a plurality of spray cavities (14). A plurality of spray assemblies (15) are arranged inside the spray cavities (14). Each spray cavity (14) on the first tail gas spray tower (7) is connected to the first tail gas absorption tower (5) through a pipeline. Each spray cavity (14) on the first tail gas absorption tower (5) is connected to the second tail gas absorption tower (6) through a pipeline. The spray assembly comprises a central pipeline (15), a plurality of branch pipelines (16) and a spray head (17). The branch pipelines (16) are arranged in four groups. The end of each branch pipeline (16) is connected to the spray head (17). The central pipeline (15) is rotatably connected to the first tail gas spray tower (7).

10. A tail gas emission treatment device in the production of ferric chloride according to claim 9, characterized in that: The spray head (17) is arranged in a bowl-shaped structure so as to be used for uniformly spraying the tail gas in the spray tower.

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