A vinyl chloride conversion system off-gas centralized treatment system

Abstract

The utility model discloses a kind of vinyl chloride conversion system waste gas centralized processing system, including caustic washing tower, the air inlet of caustic washing tower is connected with converter, catalyst maintenance's waste gas pipeline passes through air inlet pump, the liquid outlet of caustic washing tower is connected with the one end of first circulation pipe through liquid discharge valve, the other end of first circulation pipe is connected with the import of circulating pump, the outlet of circulating pump is connected with the one end of second circulation pipe, the other end of second circulation pipe is connected with the spray pipe import of caustic washing tower, first circulation pipe, second circulation pipe are equipped with first valve, second valve respectively on it. Advantage: by newly added pipeline, waste gas in the process of equipment pressure relief, replacement, drying gas and catalyst upset is collected to caustic washing tower, high altitude is discharged after absorption treatment, caustic washing tower realizes the liquid supplement, circulation and discharge of lye by automatic control, efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of machinery, specifically to a centralized treatment system for waste gas from a vinyl chloride conversion system. Background Technology

[0002] In the calcium carbide-based acetylene-PVC production of vinyl chloride, waste gas from the vinyl chloride synthesis converter during depressurization, replacement, drying, and catalyst turning processes is directly discharged to the outside. Because the discharged waste gas contains dissolved vinyl chloride, acetylene, and hydrogen chloride, it is prone to ignition and explosion upon contact with an ignition source. Therefore, the waste gas must be treated before discharge to avoid environmental pollution and harm to the health of operators. Current treatment methods typically involve passing the gas through a water scrubbing tower and an alkali scrubbing tower. The alkali scrubbing tower uses acid-base neutralization to remove hydrochloric acid from the gas. However, the alkali solution in the alkali scrubbing tower is recycled for extended periods, resulting in excessive consumption. Currently, replenishment is mostly done manually by observing the level gauge. Furthermore, excessive hydrochloric acid removal leads to insufficient purity of the alkali solution, requiring periodic manual removal of waste alkali solution and replenishment of fresh alkali solution. This results in low automation and reduced purification efficiency. Utility Model Content

[0003] The purpose of this invention is to provide a centralized treatment system for waste gas from a vinyl chloride conversion system.

[0004] This utility model is implemented by the following technical solution:

[0005] A centralized waste gas treatment system for a vinyl chloride conversion system includes an alkaline scrubbing tower. The inlet of the alkaline scrubbing tower is connected to the waste gas pipeline of the converter and catalyst maintenance via an air intake pump. The outlet of the alkaline scrubbing tower is connected to one end of a first circulation pipe via a drain valve. The other end of the first circulation pipe is connected to the inlet of a circulation pump. The outlet of the circulation pump is connected to one end of a second circulation pipe. The other end of the second circulation pipe is connected to the inlet of the spray pipe of the alkaline scrubbing tower. A first valve and a second valve are respectively provided on the first circulation pipe and the second circulation pipe.

[0006] A discharge pipe is connected to the second circulation pipe between the circulation pump and the second valve via a discharge valve.

[0007] It also includes an alkali tank and a connecting pipe. The outlet of the alkali tank is connected to the first circulation pipe between the first valve and the circulation pump through an outlet valve. One end of the connecting pipe is connected to the second circulation pipe between the discharge pipe and the second valve, and the other end of the connecting pipe is connected to the first circulation pipe between the discharge valve and the first valve. A connecting valve is provided on the connecting pipe. A replenishment port is provided above the discharge port of the alkali washing tower. The replenishment port is connected to the first circulation pipe between the discharge valve and the first valve through a replenishment valve.

[0008] It also includes a PLC controller and a level switch. The signal output terminal of the level switch is connected to the signal input terminal of the PLC controller. The PLC controller is electrically connected to the drain valve, the first valve, the second valve, the discharge valve, the outlet valve, the connecting valve, and the replenishing valve.

[0009] Preferably, the outlet of the alkali washing tower is connected to a high-level vent pipe.

[0010] Preferably, it also includes a backup pump, with another outlet on the alkali tank connected to the inlet of the backup pump, and the outlet of the backup pump connected to the second circulation pipe between the second valve and the spray pipe inlet of the alkali washing tower via a backup valve; the PLC controller is electrically connected to the backup valve.

[0011] Preferably, the drain valve, the first valve, the second valve, the discharge valve, the outlet valve, the connecting valve, the replenishing valve, and the standby valve are all electrically controlled butterfly valves.

[0012] The advantages of this utility model are as follows: by adding a pipeline and having multiple valves automatically open and close, the new alkali solution can be automatically drawn into the alkali washing tower for replenishment. The liquid level is monitored by a liquid level switch, which replaces manual labor, saving time and effort. Secondly, the waste alkali solution is discharged automatically by controlling the action of multiple valves through a PLC controller, avoiding manual operation and improving purification efficiency. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0015] Figure 2 This is the control block diagram of this utility model.

[0016] In the diagram: 1. Alkali washing tower; 2. Waste gas pipeline; 3. Inlet pump; 4. Drain valve; 5. First circulation pipe; 6. First valve; 7. Circulation pump; 8. Second circulation pipe; 9. Second valve; 10. Discharge pipe; 11. Discharge valve; 12. Alkali tank; 13. Connecting pipe; 14. Connecting valve; 15. Discharge valve; 16. Makeup port; 17. Makeup valve; 18. PLC controller; 19. Liquid level switch; 20. High-level vent pipe; 21. Standby pump; 22. Standby valve. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] like Figure 1 , Figure 2 As shown, a centralized waste gas treatment system for a vinyl chloride conversion system includes an alkaline scrubbing tower 1. The inlet of the alkaline scrubbing tower 1 is connected to the waste gas pipeline 2 for the converter and catalyst maintenance via an inlet pump 3. The outlet of the alkaline scrubbing tower 1 is connected to one end of a first circulation pipe 5 via a drain valve 4. The other end of the first circulation pipe 5 is connected to the inlet of a circulation pump 7. The outlet of the circulation pump 7 is connected to one end of a second circulation pipe 8. The other end of the second circulation pipe 8 is connected to the inlet of the spray pipe of the alkaline scrubbing tower 1. A first valve 6 and a second valve 9 are respectively provided on the first circulation pipe 5 and the second circulation pipe 8.

[0019] The exhaust gas is drawn into the alkaline washing tower 1 by the air intake pump 3, and then rises upward. The drain valve 4, the first valve 6, and the second valve 9 are opened. The alkaline solution at the bottom of the alkaline washing tower 1 is drawn out by the circulation pump 7, and enters the spray pipe of the alkaline washing tower 1 through the first circulation pipe 5 and the second circulation pipe 8. It drips down from the alkaline solution tower 1, comes into contact with the exhaust gas, removes hydrochloric acid, and the falling alkaline solution returns to the bottom for recirculation. The gas is discharged from the top of the alkaline washing tower 1.

[0020] A discharge pipe 10 is connected to the second circulation pipe 8 between the circulation pump 7 and the second valve 9 via a discharge valve 11;

[0021] When the drain valve 4, the first valve 6, and the discharge valve 11 are opened, and the second valve 9 is closed, the alkaline solution at the bottom of the alkaline washing tower 1 drops. When it needs to be discharged or when it needs to be emptied for maintenance, the alkaline solution is drawn out by the circulation pump 7, passes through the first circulation pipe 5 and the second circulation pipe 8, and enters the discharge pipe 10, from which it is discharged.

[0022] It also includes an alkali tank 12 and a connecting pipe 13. The outlet of the alkali tank 12 is connected to the first circulation pipe 5 between the first valve 6 and the circulation pump 7 through the outlet valve 15. One end of the connecting pipe 13 is connected to the second circulation pipe 8 between the discharge pipe 10 and the second valve 9. The other end of the connecting pipe 13 is connected to the first circulation pipe 5 between the discharge valve 4 and the first valve 6. A connecting valve 14 is provided on the pipe connection. A replenishment port 16 is provided above the discharge port of the alkali washing tower 1. The replenishment port 16 is connected to the first circulation pipe 5 between the discharge valve 4 and the first valve 6 through the replenishment valve 17.

[0023] When the purity of the alkali solution decreases or when it needs to be replenished, the drain valve 4, the first valve 6, the second valve 9, and the discharge valve 11 are closed, while the outlet valve 15, the connecting valve 14, and the replenishment valve 17 are opened. The circulation pump 7 draws out the new alkali solution from the alkali solution tank and enters the bottom of the alkali washing tower 1 through the second circulation pipe 8, the connecting pipe 13, the first circulation pipe 5, and the replenishment port 16.

[0024] It also includes a PLC controller 18 and a liquid level switch 19. The signal output terminal of the liquid level switch 19 is connected to the signal input terminal of the PLC controller 18. The PLC controller 18 is electrically connected to the drain valve 4, the first valve 6, the second valve 9, the discharge valve 11, the outlet valve 15, the connecting valve 14, and the replenishing valve 17, respectively.

[0025] The level switch 19 can sense the alkali liquid level at the bottom of the alkali washing tower 1. When the liquid level drops, a signal is sent to the PLC controller 18. The PLC controller 18 controls the operation of the drain valve 4, the first valve 6, the second valve 9, the discharge valve 11, the outlet valve 15, the connecting valve 14, and the replenishment valve 17 to realize the above-mentioned alkali replenishment process. After replenishment, the switch is reset. When the alkali is circulating, the liquid level should be higher than the level switch 19.

[0026] The outlet of the alkaline washing tower 1 is connected to a high-level vent pipe 20. The gas is discharged from the high-level vent pipe 20 at the top of the alkaline washing tower 1, which reduces the flow of gas in the space where personnel are active below and reduces the risk.

[0027] It also includes a backup pump 21, another outlet on the alkali tank 12 is connected to the inlet of the backup pump 21, and the outlet of the backup pump 21 is connected to the second circulation pipe 8 between the second valve 9 and the spray pipe inlet of the alkali washing tower 1 through a backup valve 22; the PLC controller 18 is electrically connected to the backup valve 22.

[0028] There are two scenarios for use: the first is to discharge alkaline solution, and the second is to replenish alkaline solution. Both are to avoid the lack of alkaline solution for spraying when discharging or replenishing the solution. The specific process is that the backup valve 22 is opened, and the backup pump 21 draws new alkaline solution from the alkaline solution tank 12 and replenishes it to the spray pipe through the second circulation pipe 8.

[0029] Drain valve 4, first valve 6, second valve 9, discharge valve 11, outlet valve 15, connecting valve 14, replenishment valve 17, and standby valve 22 are all electrically controlled butterfly valves.

[0030] Working principle: The exhaust gas is drawn into the alkaline washing tower 1 by the air inlet pump 3 and then rises upward.

[0031] (1) Alkali circulation spray: Drain valve 4, first valve 6 and second valve 9 are opened, and replenishment valve 17, connecting valve 14, outlet valve 15, discharge valve 11 and standby valve 22 are closed. The alkali solution at the bottom of the alkali washing tower 1 is drawn out by the circulation pump 7, enters the spray pipe of the alkali washing tower 1 through the first circulation pipe 5 and the second circulation pipe 8, and sprays down from the alkali tower 1 to contact the waste gas.

[0032] (2) Alkali discharge: Drain valve 4, first valve 6, and discharge valve 11 are opened, and second valve 9, replenishment valve 17, connecting valve 14, and outlet valve 15 are closed. The alkali at the bottom of the alkali washing tower 1 is drawn out by the circulating pump 7, passes through the first circulating pipe 5 and the second circulating pipe 8, enters the discharge pipe 10, and is discharged from the discharge pipe 10.

[0033] At the same time, the standby valve 22 is opened, and the standby pump 21 draws the new alkali solution from the alkali solution tank 12, and replenishes it to the spray pipe through the second circulation pipe 8. The sprayed alkali solution also has to pass through the packing layer, and the speed at which it falls to the bottom of the alkali washing tower 1 is slow, which increases the discharge speed and can achieve the effect of fast discharge and slow replenishment, thereby achieving the purpose of discharge.

[0034] (3) Alkali replenishment: The position switch 19 can sense the alkali liquid level at the bottom of the alkali washing tower 1. When the liquid level drops, a signal is sent to the PLC controller 18, and the drain valve 4, the first valve 6, the second valve 9, and the discharge valve 11 are closed. The outlet valve 15, the connecting valve 14, and the replenishment valve 17 are opened. The circulation pump 7 draws out the new alkali liquid from the alkali pool and enters the bottom of the alkali washing tower 1 through the second circulation pipe 8, the connecting pipe 13, the first circulation pipe 5, and the replenishment port 16.

[0035] At the same time, the backup valve 22 is opened, and the backup pump 21 draws new alkali solution from the alkali solution tank 12 and replenishes it to the spray pipe through the second circulation pipe 8. The falling alkali solution can also play a role in replenishing at the same time.

[0036] Advantages: By adding new pipelines and multiple valves that automatically open and close, new alkali solution can be automatically drawn into the alkali washing tower 1 for replenishment. The liquid level is monitored by the liquid level switch 19, replacing manual labor, saving time and effort. Secondly, waste alkali solution is discharged automatically by controlling the action of multiple valves through the PLC controller 18, avoiding manual operation and improving purification efficiency.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A centralized waste gas treatment system for a vinyl chloride conversion system, characterized in that, The system includes an alkaline scrubbing tower. The air inlet of the alkaline scrubbing tower is connected to the exhaust gas pipeline of the converter and catalyst maintenance via an air inlet pump. The liquid outlet of the alkaline scrubbing tower is connected to one end of a first circulation pipe via a liquid outlet valve. The other end of the first circulation pipe is connected to the inlet of a circulation pump. The outlet of the circulation pump is connected to one end of a second circulation pipe. The other end of the second circulation pipe is connected to the inlet of the spray pipe of the alkaline scrubbing tower. A first valve and a second valve are respectively provided on the first circulation pipe and the second circulation pipe. A discharge pipe is connected to the second circulation pipe between the circulation pump and the second valve via a discharge valve. It also includes an alkali tank and a connecting pipe. The outlet of the alkali tank is connected to the first circulation pipe between the first valve and the circulation pump through an outlet valve. One end of the connecting pipe is connected to the second circulation pipe between the discharge pipe and the second valve, and the other end of the connecting pipe is connected to the first circulation pipe between the discharge valve and the first valve. A connecting valve is provided on the connecting pipe. A replenishment port is provided above the discharge port of the alkali washing tower. The replenishment port is connected to the first circulation pipe between the discharge valve and the first valve through a replenishment valve. It also includes a PLC controller and a level switch. The signal output terminal of the level switch is connected to the signal input terminal of the PLC controller. The PLC controller is electrically connected to the drain valve, the first valve, the second valve, the discharge valve, the outlet valve, the connecting valve, and the replenishing valve.

2. The centralized waste gas treatment system for a vinyl chloride conversion system according to claim 1, characterized in that: The outlet of the alkaline washing tower is connected to a high-level vent pipe.

3. The centralized waste gas treatment system for a vinyl chloride conversion system according to claim 1, characterized in that: It also includes a backup pump, with another outlet on the alkali tank connected to the inlet of the backup pump, and the outlet of the backup pump connected to the second circulation pipe between the second valve and the spray pipe inlet of the alkali washing tower via a backup valve; the PLC controller is electrically connected to the backup valve.

4. The centralized waste gas treatment system for a vinyl chloride conversion system according to claim 3, characterized in that: The drain valve, the first valve, the second valve, the discharge valve, the outlet valve, the connecting valve, the replenishing valve, and the standby valve are all electrically controlled butterfly valves.

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