A converter gas recovery system

Abstract

The utility model belongs to converter coal gas recovery technical field especially relates to a converter coal gas recovery system, sets up movable smoke hood above converter, connects vaporization cooling flue above movable smoke hood, vaporization cooling flue connects ring slit scrubbing tower, dehydrator, air blower and three -way valve in proper order, another two ports of three -way valve are connected respectively and diffuse tower and rotary water seal valve, rotary water seal valve connects water seal, water seal is connected by pipeline and gas holder, nitrogen gas purging pipeline is connected in close rotary water seal valve entrance between three -way valve export and rotary water seal valve entrance, discharge pipeline is connected out in close three -way valve export between three -way valve export and rotary water seal valve entrance, water seal export and gas holder entrance are connected and the anti -blow pipeline is connected out, close water seal export top configuration anti -blow valve, anti -blow pipeline is connected and diffuse tower. The system forms space cooperation through nitrogen gas purging pipeline, anti -blow pipeline and discharge pipeline, and quickly removes the unqualified gas that lingers, shortens system recovery time, reduces gas waste.

Description

Technical Field

[0001] This utility model belongs to the field of converter gas recovery technology, and in particular relates to a converter gas recovery system. Background Technology

[0002] During converter gas recovery, an oxygen content exceeding the standard (>2%) at the gas holder inlet will trigger a safety interlock, leading to gas venting and system shutdown. In existing technology, after the oxygen analyzer detects an excess, the three-way valve switches to the venting side. However, the substandard gas remaining in the pipeline between the three-way valve and the water seal valve cannot be quickly discharged. This causes residual gas to mix with qualified gas during subsequent recovery, resulting in a secondary oxygen content exceeding the standard. Current solutions rely on manual backflushing and replacement with gas from the gas holder, which is inefficient and wastes gas. Utility Model Content

[0003] The purpose of this invention is to provide a converter gas recovery system that solves the problem of low efficiency and gas waste caused by the existing schemes that rely on manual backflushing and replacement of gas in gas holders.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A converter gas recovery system includes a converter, a movable fume hood above the converter, a vaporization cooling flue connected above the movable fume hood, the end of the vaporization cooling flue connected to the top of an annular scrubbing tower, the annular scrubbing tower connected to a dehydrator, a dust removal pipe of the dehydrator connected to a blower, the end of the blower connected to a three-way valve, the other two ports of the three-way valve connected to a venting tower and a rotary water seal valve respectively via pipes, a bypass pipe connected between the blower and the three-way valve, a bypass valve connected to the bypass pipe, the bypass pipe connected to the pipe between the three-way valve and the venting tower, a No. 1 oxygen analyzer inserted at the front end of the bypass pipe, the rotary water seal valve connected to a water seal, the water seal connected to a gas holder via a pipe, a venting pipe connected near the water seal outlet on the pipe, a venting valve installed on the venting pipe, a No. 2 oxygen analyzer inserted near the gas holder on the pipe. Oxygen analyzer; a nitrogen purging pipeline is connected between the outlet of the three-way valve and the inlet of the rotary water seal valve near the inlet of the rotary water seal valve. A nitrogen control valve is installed on the nitrogen purging pipeline near the inlet of the rotary water seal valve. A nitrogen flow regulating valve is connected to the first end of the nitrogen purging pipeline. A discharge pipeline is connected between the outlet of the three-way valve and the inlet of the rotary water seal valve near the outlet of the three-way valve. A discharge valve is installed near the outlet of the three-way valve. The discharge pipeline is connected to a venting tower. A check valve is installed near the venting tower. Oxygen analyzer #4 is connected to the front end of the check valve on the discharge pipeline. A backflush pipeline is connected between the outlet of the water seal valve and the inlet of the gas holder. A backflush valve is installed near the top of the water seal outlet. The backflush pipeline is connected to a venting tower. A check valve is installed near the venting tower. Oxygen analyzer #3 is connected to the front end of the check valve on the backflush pipeline.

[0006] Oxygen analyzers #1, #2, #3, and #4 are all interlocked with a three-way valve, nitrogen control valve, exhaust valve, bypass valve, and venting valve via a PLC control system. When oxygen analyzer #1 detects excessive oxygen content, the three-way valve automatically switches to the venting side, and simultaneously opens the nitrogen control valve and exhaust valve to replace the stagnant coal gas before discharging it to the venting tower. When oxygen analyzer #1 detects that the oxygen content is within acceptable limits, the three-way valve automatically switches to the recovery side. Oxygen analyzer #2 is interlocked with a three-way valve, nitrogen control valve, and exhaust valve. When oxygen analyzer #2 detects excessive oxygen content, the three-way valve automatically switches to the venting side, and simultaneously opens the nitrogen control valve and exhaust valve to replace the stagnant coal gas before discharging it to the venting tower. At the same time, the backflush valve automatically opens to replace the stagnant coal gas before discharging it to the venting tower.

[0007] Preferably, the oxygen analyzer #3 and oxygen analyzer #4 are interlocked with the three-way valve, nitrogen control valve, exhaust valve, bypass valve and vent valve through a PLC control system.

[0008] Preferably, the distance between the nitrogen purging pipeline and the inlet of the rotary water seal valve is ≤0.5D, where D is the diameter of the main pipeline and the nitrogen inlet pressure is ≥0.6MPa.

[0009] Preferably, the distance between the discharge pipe and the outlet of the three-way valve is ≤0.3D, where D is the diameter of the main pipe.

[0010] Preferably, the backflush pipe is ≤0.2m from the top of the water seal tank outlet.

[0011] Preferably, the No. 1 oxygen analyzer is located 1.5D upstream of the three-way valve, with a range of 0-10% O2 and a detection cycle of ≤1s.

[0012] Preferably, the No. 2 oxygen analyzer is located 2D before the gas holder inlet, with a range of 0-5% O2 and temperature compensation.

[0013] Preferably, both the No. 3 oxygen analyzer and the No. 4 oxygen analyzer adopt TDLAS laser analysis technology with a detection limit of 0.05% O2.

[0014] Preferably, the nitrogen purging pipe, backflushing pipe, and discharge pipe are all stainless steel pipes.

[0015] Working principle: The flue gas generated by the converter is captured by the movable fume hood, absorbs some heat through the vaporization cooling flue, and then passes through the annular scrubbing tower, where it is purified by gravity dehydration. The purified flue gas enters the blower through the dust removal pipeline. When the gas content in the flue gas meets the set value and the oxygen content is lower than 1.8%, the recovery conditions are met. The flue gas is then sent to the gas holder through the three-way valve (recovery side) after the blower, the rotary water seal valve, and the water seal, completing the recovery. If the flue gas does not meet the requirements, it is discharged into the atmosphere for combustion through the three-way valve (venting side) and the venting chimney.

[0016] The beneficial effects achieved by this utility model are:

[0017] (1) By forming spatial coordination through nitrogen purging pipeline, backflushing pipeline and discharge pipeline, the residual unqualified coal gas can be quickly removed, the replacement efficiency can be improved, and combined with oxygen analyzer No. 1 and oxygen analyzer No. 2, the oxygen content can be prevented from exceeding the standard for the second time and triggering the safety interlock. In the event of triggering the safety interlock, the system recovery time can be shortened and coal gas waste can be reduced.

[0018] (2) The flow rate of nitrogen is dynamically adjusted according to the degree of oxygen content exceeding the standard detected by oxygen analyzer 1 or oxygen analyzer 2 through the flow regulating valve; the purge is triggered by double interlocking of oxygen analyzer 1 or oxygen analyzer 2 to prevent unqualified coal gas from entering the gas holder and reduce the risk of manual operation; the outlet of the discharge valve and backflush valve is connected to the venting tower to ensure the safe combustion of the replacement gas.

[0019] (3) Install oxygen analyzer No. 3 and oxygen analyzer No. 4 at the connection points of the backflush pipe and the discharge pipe to the venting tower to accurately control the purging and replacement situation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure in an embodiment of the present utility model.

[0021] Explanation of reference numerals in the attached drawings: 1. Converter; 2. Movable fume hood; 3. Vaporization cooling flue; 4. Circular seam scrubber; 5. Dehydrator; 6. Blower; 7. Three-way valve; 8. Venting tower; 9. Rotary water seal valve; 10. Water seal; 11. Gas holder; 12. Oxygen analyzer #1; 13. Oxygen analyzer #2; 14. Backflush valve; 15. Backflush pipe; 16. First check valve; 17. Oxygen analyzer #3; 18. Discharge valve; 19. Second check valve; 20. Oxygen analyzer #4; 21. Nitrogen control valve; 22. Nitrogen purging pipe; 23. Nitrogen flow regulating valve; 24. Discharge pipe; 25. Bypass pipe; 26. Bypass valve; 27. Venting pipe; 28. Venting valve. Detailed Implementation

[0022] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings and embodiments.

[0023] like Figure 1As shown, a converter gas recovery system includes a converter 1, a movable fume hood 2 installed above the converter 1, a vaporization cooling flue 3 connected above the movable fume hood 2, the end of the vaporization cooling flue 3 connected to the top of an annular scrubbing tower 4, the annular scrubbing tower 4 connected to a dehydrator 5, the dehydrator 5 connected to a blower 6, the end of the blower 6 connected to a three-way valve 7, the other two ports of the three-way valve 7 connected to a venting tower 8 and a rotary water seal valve 9 respectively via pipes, and the blower 6 and the three-way valve 7 are connected to... A bypass pipe 25 is indirectly connected to a bypass valve 26. The bypass pipe 25 is connected to the pipeline between the three-way valve 7 and the venting tower 8. The front end of the bypass pipe 25 is connected to oxygen analyzer 12 (#1). A rotary water seal valve 9 is connected to a water seal 10. The water seal 10 is connected to the gas holder 11 via a pipeline. A vent pipe 27 is connected to the pipeline near the outlet of the water seal 10. A vent valve 28 is installed on the vent pipe 27. An oxygen analyzer 13 (#2) is connected to the pipeline near the gas holder 11. A three-way valve is also connected. A nitrogen purging pipe 22 is connected between the outlet of valve 7 and the inlet of rotary water seal valve 9, near the inlet of rotary water seal valve 9. A nitrogen control valve 21 is installed on the nitrogen purging pipe 22 near the inlet of rotary water seal valve 9. The first end of the nitrogen purging pipe 22 is connected to a nitrogen flow regulating valve 23. A discharge pipe 24 is connected between the outlet of three-way valve 7 and the inlet of rotary water seal valve 9, near the outlet of three-way valve 7. A discharge valve 18 is installed near the outlet of three-way valve 7. The discharge pipe 24 is connected to the venting tower 8. A second check valve 19 is installed near the venting tower 8. A #4 oxygen analyzer 20 is inserted into the front end of the second check valve 19 on the discharge pipe 24. A backflush pipe 15 is connected between the outlet of water seal 10 and the inlet of gas holder 11. A backflush valve 14 is installed near the top of the outlet of water seal 10. The backflush pipe 15 is connected to the venting tower 8. A first check valve 16 is installed near the venting tower 8. A #3 oxygen analyzer 17 is inserted into the front end of the first check valve 16 on the backflush pipe 15.

[0024] Oxygen analyzer 12 and oxygen analyzer 13 are interlocked with three-way valve 7, nitrogen control valve 21, exhaust valve 18, bypass valve 26 and vent valve 28 through a PLC control system.

[0025] In this embodiment, the control system adopts a Siemens S7-300 series PLC and is configured with a fuzzy PID algorithm (setting PID parameters Kp=0.8, Ki=0.05) to dynamically adjust the nitrogen flow rate with a response time of <0.5 seconds. According to the actual test of a 180-ton converter in a steel plant, the system can shorten the residual gas replacement time from 120 seconds in the original process to 45 seconds, reducing the gas release by 12.7 Nm³ / cycle.

[0026] The workflow is as follows:

[0027] Initial state: Three-way valve 7 is on the recovery side, nitrogen control valve 21, discharge valve 18, and backflush valve 14 are closed, and coal gas is normally recovered through three-way valve 7 → rotary water seal valve 9 → water seal 10 → gas holder 11.

[0028] Trigger purge:

[0029] When the oxygen analyzer 12 detects an oxygen content > 1.8% (early warning threshold), the PLC control system automatically executes the following: the three-way valve switches to the venting side within 3 seconds, and the nitrogen control valve 21 and the discharge valve 18 are opened simultaneously; the nitrogen flow regulating valve 23 is started to dynamically adjust the nitrogen flow rate (0-500 Nm³ / h) according to the oxygen content value.

[0030] Replacement process: High-pressure nitrogen is injected into the blind end of the pipeline through nitrogen purging pipeline 22. The nitrogen and the retained coal gas are fully mixed in the mixing section. The mixed gas is discharged into the venting tower 8 for combustion through the discharge valve 18 at a flow rate of 15 m / s.

[0031] Termination conditions:

[0032] When the oxygen analyzer (#3) detects an oxygen content of <0.5% for 5 seconds, the PLC automatically executes:

[0033] Close nitrogen control valve 21 and discharge valve 18, maintain the three-way valve 7 in the venting side state for 8 seconds (can be set to 5-10 seconds), and finally reset the three-way valve to the recovery side.

[0034] When the oxygen content detected by the oxygen analyzer 13 for the second time is greater than 2%, the PLC control system automatically executes the following: the three-way valve switches to the venting side within 3 seconds, and the nitrogen control valve 21, the discharge valve 18, and the backflush valve 14 are opened simultaneously. The nitrogen flow regulating valve 23 is started to dynamically adjust the nitrogen flow rate (0-500 Nm³ / h) according to the oxygen content value.

[0035] Replacement process (1): High-pressure nitrogen is injected into the blind end of the pipeline through nitrogen purging pipe 22.

[0036] Nitrogen and retained coal gas are fully mixed in the mixing section, and the mixed gas is discharged into the venting tower 8 for combustion through the discharge valve 18 at a flow rate of 15 m / s.

[0037] Replacement process (II): The qualified coal gas and the stagnant coal gas in the gas holder 11 are fully mixed. The mixed gas is discharged into the venting tower 8 at a flow rate of 15 m / s through the backflush valve 14 for combustion, forming a two-way replacement with the replacement process (I).

[0038] By using nitrogen replacement and gas backflushing, the time for removing stagnant gas is shortened by more than 70%, preventing unqualified gas from entering the gas holder, ensuring safety and reliability. At the same time, it reduces the amount of qualified gas released, saving approximately 800,000 to 1,300,000 Nm³ of gas recovery per year, thus saving energy and reducing consumption.

Claims

1. A converter gas recovery system, comprising a converter, a movable fume hood disposed above the converter, a vaporization cooling flue connected above the movable fume hood, the end of the vaporization cooling flue connected to the top of an annular scrubbing tower, the annular scrubbing tower connected to a dewatering unit, a dust removal pipe of the dewatering unit connected to a blower, and a three-way valve connected to the end of the blower, characterized in that... The other two ports of the three-way valve are connected to the venting tower and the rotary water seal valve respectively via pipelines. A bypass pipe is connected between the blower and the three-way valve, and a bypass valve is connected to the bypass pipe. The bypass pipe is connected to the pipeline between the three-way valve and the venting tower, and the front end of the bypass pipe is connected to oxygen analyzer #1. The rotary water seal valve is connected to a water seal, and the water seal is connected to the gas holder via a pipeline. A vent pipe is connected to the pipeline near the water seal outlet, and a vent valve is installed on the vent pipe. Oxygen analyzer #2 is connected to the pipeline near the gas holder. A nitrogen purging pipeline is connected between the outlet of the three-way valve and the inlet of the rotary water seal valve, near the inlet of the rotary water seal valve. A nitrogen control valve is installed on the nitrogen purging pipeline near the inlet of the rotary water seal valve, and the first end of the nitrogen purging pipeline is connected to a nitrogen flow meter. The regulating valve has a discharge pipe connected to the outlet of the three-way valve and the inlet of the rotary water seal valve near the outlet of the three-way valve. A discharge valve is installed near the outlet of the three-way valve. The discharge pipe is connected to the venting tower. A check valve is installed near the venting tower. The front end of the check valve on the discharge pipe is connected to oxygen analyzer #4. A backflush pipe is connected to the outlet of the water seal valve and the inlet of the gas holder. A backflush valve is installed near the top of the water seal outlet. The backflush pipe is connected to the venting tower. A check valve is installed near the venting tower. The front end of the check valve on the backflush pipe is connected to oxygen analyzer #3. Oxygen analyzers #1, #2, #3, and #4 are all interlocked with the three-way valve, nitrogen control valve, discharge valve, bypass valve, and venting valve through a PLC control system.

2. The converter gas recovery system according to claim 1, characterized in that, The distance between the nitrogen purging pipeline and the inlet of the rotary water seal valve is ≤0.5D, where D is the diameter of the main pipeline and the nitrogen inlet pressure is ≥0.6MPa.

3. The converter gas recovery system according to claim 1, characterized in that, The distance between the discharge pipe and the outlet of the three-way valve is ≤0.3D, where D is the diameter of the main pipe.

4. The converter gas recovery system according to claim 1, characterized in that, The distance between the backflush pipe and the top of the water seal tank outlet is ≤0.2m.

5. A converter gas recovery system according to claim 1, characterized in that, The No. 1 oxygen analyzer is located 1.5D upstream of the three-way valve, with a range of 0-10% O2 and a detection cycle of ≤1s.

6. A converter gas recovery system according to claim 1, characterized in that, The No. 2 oxygen analyzer is located 2D before the gas holder inlet, with a range of 0-5% O2 and temperature compensation.

7. A converter gas recovery system according to claim 1, characterized in that, Both oxygen analyzers #3 and #4 employ TDLAS laser analysis technology, with a detection limit of 0.05% O2.

8. A converter gas recovery system according to claim 1, characterized in that, The nitrogen purging pipeline, backflush pipeline, and discharge pipeline are all made of stainless steel.

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