Caustic soda recovery device

Abstract

The utility model discloses a caustic soda recovery device which comprises an alkali liquor recovery tank, an alkali liquor circulating pump, an alkali liquor tubular heat exchanger and a sodium carbonate circulating tank which are connected in sequence, a first inlet and a second inlet are formed in the top of the alkali liquor recovery tank, and one end of the first inlet is connected with a 73% alkali emptying pipe, a caustic soda flake machine overflow pipe and a distributor overflow pipe. The other end of the first inlet enters an alkali liquor recovery tank and is internally provided with 3-5 inclined baffles which are staggered left and right from top to bottom, the bottom of the alkali liquor recovery tank is connected with an alkali liquor circulating pump through a pipeline, an outlet of the alkali liquor circulating pump is connected with an inlet of an alkali liquor tubular heat exchanger through a pipeline, and an outlet of the alkali liquor tubular heat exchanger is provided with a pipeline A; a pipeline B connected with a circulation port of the alkali liquor recycling tank and a pipeline C connected with an inlet of the sodium carbonate circulation tank are respectively arranged on the pipeline A. By using the device, the alkali liquor is effectively recycled, the production cost is reduced, the safety coefficient of production is improved, and the service life of equipment is protected.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical industry, in particular to a caustic soda recovery device. Background Art

[0002] During the production process of caustic soda flakes, four caustic soda flake machines produce caustic soda flakes at the same time, and the concentration of produced caustic soda flakes is ≥98%. When one of the caustic soda flake machines is shut down for maintenance, the alkali solution entering the caustic soda flake machine cannot be recovered, and the final concentrator needs to reduce the flow rate for maintenance. When the flow rate is reduced, due to the rapid drop in the flow rate, it is easy to cause uneven distribution of liquid in the falling film tube of the final concentrator, causing the film formation to deteriorate and forming a dry wall area. The temperature difference between the dry wall area and the non-dry wall area is large, causing stress, thereby causing the tube to bend and deform, which will affect the concentration efficiency, service life and safety performance of the final concentrator.

[0003] On the other hand, when the flake caustic soda system needs to be shut down for maintenance, the alkali with concentration ≥73% and concentration ≥98% in the ascending membrane concentrator, final concentrator, flake caustic soda machine and pipelines must be drained. After draining the alkali, the residual alkali in the ascending membrane concentrator, final concentrator, flake caustic soda machine and pipelines must be rinsed clean. The discharged waste alkali liquid is highly corrosive. If the waste alkali liquid is not recycled and treated, high-concentration waste alkali liquid enters the sewage biochemical treatment system, which will not only destroy the growth and reproduction of microorganisms, but also cause the death of microorganisms in severe cases, thereby affecting the normal operation of sewage treatment and the compliance of total wastewater discharge.

[0004] The existing solution to the problem of recycling waste alkali liquid is to use a movable open stainless steel round barrel with a stainless steel round cover on top of the barrel to keep the barrel dry and directly discharge the waste alkali liquid into the barrel. If the barrel contains water, the waste alkali liquid releases a large amount of heat when it encounters the water in the barrel, and the water vaporizes instantly. The water vapor carries the alkali and splashes out of the barrel. After the barrel temperature drops to room temperature, a forklift transports the barrel to the alkali liquid recovery pool. This method not only causes scalds to personnel, but also increases the risk of burns to personnel during transportation and recovery. Summary of the invention

[0005] The purpose of the utility model is to solve the problem of recycling liquid caustic soda entering the caustic soda flake machine during its maintenance process, avoid frequent lifting and lowering of the load to damage the final concentrator, and at the same time recycle the caustic soda in the entire system, thereby reducing production costs and environmental pollution, turning waste into treasure, protecting the environment, and improving the economic benefits of the enterprise.

[0006] The utility model adopts the following technical scheme to solve the technical problem: it comprises an alkali liquid recovery tank, an alkali liquid circulation pump, an alkali liquid shell and tube heat exchanger and a sodium carbonate circulation tank which are connected in sequence; a first inlet and a second inlet are arranged on the top of the alkali liquid recovery tank; one end of the first inlet is connected to a 73% alkali drain pipe, an overflow pipe of an alkali flake machine and an overflow pipe of a distributor; the other end of the first inlet enters the alkali liquid recovery tank and 3-5 inclined baffles are arranged inside the alkali liquid recovery tank which are staggered from top to bottom and from left to right; a steam coil is arranged at the bottom of the alkali liquid recovery tank; the bottom of the alkali liquid recovery tank is connected to the alkali liquid circulation pump through a pipeline; the outlet of the alkali liquid circulation pump is connected to the inlet of the alkali liquid shell and tube heat exchanger through a pipeline; an A pipeline is arranged at the outlet of the alkali liquid shell and tube heat exchanger; a B pipeline connected to the circulation port of the alkali liquid recovery tank and a C pipeline connected to the inlet of the sodium carbonate circulation tank are respectively arranged on the A pipeline.

[0007] Furthermore, the second inlet is provided with a water supply pipeline, and by adopting the above technical solution, water is supplied to the alkali solution recovery tank to dilute the high-concentration alkali solution, and the alkali solution concentration is diluted to ≤30%.

[0008] Furthermore, a alkali solution circulation pneumatic regulating valve is provided on the B pipeline.

[0009] Furthermore, A is provided with a remote density meter. By adopting the above technical solution, the staff can detect the concentration of the diluted alkali solution online, and dilute the concentration to ≤30% in time to send it to the sodium carbonate circulation pipe to configure sodium carbonate.

[0010] Furthermore, a pneumatic regulating valve for recovering alkali liquid is provided on the C pipeline.

[0011] Furthermore, the alkali solution circulation pump is provided with a remote start switch. By adopting the above technical solution, the staff can remotely control the start and stop of the alkali solution circulation pump, thereby reducing the labor intensity and safety factor of the on-site staff.

[0012] Furthermore, the baffle is made of nickel, the distance between the baffles is 350-400mm, and the inclination angle of the baffle is 62°. By adopting the above technical solution, on the one hand, the alkali solution releases a large amount of heat when encountering the water in the alkali solution circulation tank, and the water vaporizes instantly, preventing the water vapor from flowing back into the caustic soda flake machine through the first inlet and affecting the caustic soda flake concentration; on the other hand, the flow rate of the recovered alkali solution entering the alkali solution recovery tank is slowed down, inhibiting the instantaneous vaporization of the alkali solution and water.

[0013] Furthermore, a thermometer and a liquid level gauge are provided at the bottom of the alkali solution recovery tank.

[0014] Furthermore, the length of the first inlet into the alkali solution recovery tank is 90-100 mm.

[0015] Furthermore, the steam coil is provided with 4-6 pipe supports.

[0016] The beneficial effects of the utility model are that, by using an alkali liquid recovery device, on the one hand, the problem of environmental pollution caused by discharged alkali liquid is solved, and effective recycling and utilization are achieved, production costs are reduced, and production efficiency is improved. At the same time, the alkali liquid is heat exchanged by the alkali liquid shell and tube heat exchanger, so the temperature of the alkali liquid is reduced, and the generation of a large amount of water vapor to cause gas expansion is avoided, the safety factor of production is improved, and the risk of employee burns is reduced; on the other hand, the baffle in the alkali liquid recovery tank can prevent water vapor from entering the caustic soda flake machine through the first inlet, reduce the wall hanging phenomenon in the silo, and increase the operating time of the alkali flake machine. In addition, through the alkali liquid recovery tank, the concentration efficiency of the final concentrator is improved, and the service life of the falling film tubes is protected. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a system schematic diagram of the utility model;

[0018] Figure 2 for Figure 1 A partial enlarged cross-sectional view of part A.

[0019] Figure 1-2 Among them, 1 is an alkali recovery tank, 2 is an alkali circulation pump, 3 is an alkali shell and tube heat exchanger, 4 is a sodium carbonate circulation tank, 5 is a 73% alkali drain pipe, 6 is an overflow pipe of a alkali flake machine, 7 is an overflow pipe of a distributor, 8 is a remote concentration meter, 9 is an alkali circulation pneumatic regulating valve, 10 is an alkali recovery pneumatic regulating valve, 11 is a thermometer and a liquid level gauge, 12 is the first inlet, 13 is the second inlet, 14 is an alkali recovery tank circulation port, 15 is a water supply pipeline, 16 is a pipeline A, 17 is a pipeline B, 18 is a pipeline C, 19 is a baffle, 20 is a steam coil, 21 is a pipeline support, a is alkali, b is water, c is circulating water, and d is steam. DETAILED DESCRIPTION

[0020] Figure 1-2As shown, a caustic soda recovery device is characterized in that it includes an alkali recovery tank 1, an alkali circulation pump 2, an alkali tube heat exchanger 3, and a sodium carbonate circulation tank 4 which are connected in sequence. The top of the alkali recovery tank 1 is provided with a first inlet 12 and a second inlet 13. One end of the first inlet 12 is connected to a 73% alkali drain pipe 5, an alkali flake machine overflow pipe 6, and a distributor overflow pipe 7. The other end of the first inlet 12 enters the alkali recovery tank and is provided with 3-5 inclined baffles 19 staggered from top to bottom. The length of the first inlet 12 entering the alkali recovery tank is 90-100 mm. The baffles 19 are made of nickel. The distance between the baffles 19 is 350-400 mm. The inclination angle of the baffles 19 is 62°. The bottom of the alkali recovery tank is provided with a steam Coil 20, the steam coil 20 is provided with a pipeline support 21, the second inlet 13 is provided with a water supply pipeline 15, the bottom of the alkali liquid recovery tank 1 is connected to the alkali liquid circulation pump 2 through a pipeline, the outlet of the alkali liquid circulation pump 2 is connected to the inlet of the alkali liquid shell and tube heat exchanger 3 through a pipeline, the outlet of the alkali liquid shell and tube heat exchanger 3 is provided with an A pipeline 16, the A pipeline 16 is provided with a remote concentration meter 8, the A pipeline 16 is also provided with a B pipeline 17 connected to the circulation port 14 of the alkali liquid recovery tank and a C pipeline 18 connected to the inlet of the sodium carbonate circulation tank 4, the B pipeline 17 is provided with an alkali liquid circulation pneumatic regulating valve 9, the C pipeline is provided with an alkali liquid recovery pneumatic regulating valve 10, the alkali liquid circulation pump 2 is provided with a remote start switch, and the bottom of the alkali liquid recovery tank 1 is provided with a thermometer and a liquid level gauge 11.

[0021] After the alkali solution flows from the first inlet 12 through the baffle 19 to slow down the flow rate of the alkali solution, it flows into the alkali solution recovery tank 1. The operator starts the alkali solution circulation pump 2 through the remote switch of the alkali solution circulation pump 2. The 100-300°C alkali solution is sent to the alkali solution tube heat exchanger 3 for cooling. The alkali solution tube heat exchanger 3 uses circulating water c for cooling. The temperature is controlled at 35-60°C through multiple cycles of cooling. At the same time, the alkali solution recovery tank 1 is replenished with water through the second inlet 13 to dilute the high-concentration alkali solution. The water replenishment pipeline 1 The water in 5 mainly comes from recycled domestic wastewater and clean plant wastewater. The operator opens the alkali solution circulation pneumatic regulating valve 9 to circulate and dilute the alkali solution. The alkali solution concentration is ≤30%. The operator opens the alkali solution recovery pneumatic regulating valve 10 and closes the alkali solution circulation pneumatic regulating valve 9. The alkali solution is sent to the sodium carbonate circulation tank 4 to prepare the sodium carbonate solution. After the liquid level is controlled at 5%-8% by the liquid level gauge at the bottom of the alkali solution recovery tank, the alkali solution circulation pneumatic regulating valve 9 is opened, the alkali solution recovery pneumatic regulating valve 10 is closed, and the alkali solution circulation pump is stopped remotely.

Claims

1. A caustic soda recovery device, characterized in that: It includes an alkali liquid recovery tank, an alkali liquid circulation pump, an alkali liquid shell and tube heat exchanger, and a sodium carbonate circulation tank which are connected in sequence. A first inlet and a second inlet are arranged on the top of the alkali liquid recovery tank. One end of the first inlet is connected to a 73% alkali drain pipe, an overflow pipe of an alkali flake machine, and an overflow pipe of a distributor. The other end of the first inlet enters the alkali liquid recovery tank, and 3-5 inclined baffles are arranged inside the alkali liquid recovery tank which are staggered from top to bottom. A steam coil is arranged at the bottom of the alkali liquid recovery tank. The bottom of the alkali liquid recovery tank is connected to the alkali liquid circulation pump through a pipeline. The outlet of the alkali liquid circulation pump is connected to the inlet of the alkali liquid shell and tube heat exchanger through a pipeline. The outlet of the alkali liquid shell and tube heat exchanger is provided with an A pipeline. The A pipeline is respectively provided with a B pipeline connected to the circulation port of the alkali liquid recovery tank and a C pipeline connected to the inlet of the sodium carbonate circulation tank.

2. A caustic soda recovery device as claimed in claim 1, characterized in that: The second inlet is provided with a water supply pipeline.

3. A caustic soda recovery device as claimed in claim 1, characterized in that: The B pipeline is provided with an alkali solution circulation pneumatic regulating valve.

4. A caustic soda recovery device as claimed in claim 3, characterized in that: The A pipeline is provided with a remote concentration meter.

5. A caustic soda recovery device as claimed in claim 1, characterized in that: The B pipeline is provided with an alkali solution recovery pneumatic regulating valve.

6. A caustic soda recovery device as claimed in claim 1, characterized in that: The alkali solution circulation pump is provided with a remote starting switch.

7. A caustic soda recovery device as claimed in claim 1, characterized in that: The baffles are made of nickel, the distance between the baffles is 350-400 mm, and the inclination angle of the baffles is 62°.

8. A caustic soda recovery device as claimed in claim 1, characterized in that: A thermometer and a liquid level gauge are arranged at the bottom of the alkali solution recovery tank.

9. A caustic soda recovery device as claimed in claim 1, characterized in that: The length of the first inlet into the alkali solution recovery tank is 90-100 mm.

10. A caustic soda recovery device according to claim 1, characterized in that: The steam coil is provided with 4-6 pipe supports.

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