Dechlorination and salt evaporation system for sodium hypochlorite wastewater

Abstract

The utility model discloses a dechlorination and salt evaporation system for sodium hypochlorite wastewater, which is characterized in that a master controller is connected with a dosing device, the dosing device is connected with a reaction kettle, the reaction kettle is connected with a pH regulating tank through a reaction liquid flowing pipeline, and the pH regulating tank is connected with a suspension basket type evaporator through an acidizing liquid flowing pipeline; and the dosing device is also connected with the pH regulating tank through a pipeline. According to the automatic control system, the full-automatic control of dechlorination and salt evaporation of the sodium hypochlorite wastewater is realized, the labor cost is reduced, the safety is improved, and errors caused by manual monitoring are reduced, so that the unnecessary energy consumption is reduced, the intellectualization and the stability of the treatment system are improved, and good economic benefits are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of sodium hypochlorite wastewater treatment, and in particular relates to a sodium hypochlorite wastewater dechlorination and salt distillation system. Background Art

[0002] Chlorine is widely used in human production and life, especially in many fields of chemical production, where it is an important raw material. However, chlorine is toxic and has strong irritation. It is easily dissolved in water under high pressure to form liquid chlorine, generating hypochlorous acid and hydrochloric acid. Chlorine is produced in the production of chemicals, pesticides, medicines and nonferrous metallurgy. In the chlorination, chlorosulfonation and oxychlorination processes of organic synthesis production, a large amount of chlorine-containing waste gas and hydrogen chloride gas are discharged, causing environmental pollution. At present, chlorine is generally treated by caustic soda absorption method, which usually uses chlorine absorption device to directly produce sodium hypochlorite as a byproduct, or produces semi-finished products and then introduces raw chlorine through sodium hypochlorite production device to produce sodium hypochlorite products. In this process, wastewater containing sodium hypochlorite will inevitably be produced. Its main components, in addition to sodium hypochlorite, also contain sodium hydroxide, sodium chloride, etc. It has strong alkalinity and strong oxidizing properties, and is a kind of salt-containing wastewater that cannot be directly discharged.

[0003] Since the composition of pollutants in sodium hypochlorite wastewater is relatively complex, sodium hypochlorite is difficult to completely treat to meet the standards, the treatment agents are expensive, and the operation process is highly dangerous, the current treatment effect of sodium hypochlorite wastewater is not satisfactory. A large amount of sodium hypochlorite wastewater is directly discharged, causing great damage to the environment.

[0004] Chinese patent CN109095677A discloses a comprehensive treatment method for sodium hypochlorite-containing wastewater and sulfuric acid titanium dioxide acid wastewater. Aiming at the problems of high treatment cost, long treatment time and high equipment requirements when the existing sodium hypochlorite-containing wastewater and sulfuric acid titanium dioxide acid wastewater are treated separately, a comprehensive treatment method is provided. Specifically, the pH value of sulfuric acid titanium dioxide acid wastewater is adjusted to 5.5-7.0, sodium hypochlorite-containing wastewater is added, mixed and reacted for 15-20 minutes, aerated and filtered to obtain treated water, wherein the sodium hypochlorite wastewater accounts for 0.5-3% of the weight percentage of sulfuric acid titanium dioxide wastewater. This method reduces the wastewater treatment process and time, saves treatment costs, and has significant economic benefits.

[0005] Chinese patent CN109879505B discloses a process for treating wastewater containing sodium hypochlorite, and the specific steps are as follows: discharge the wastewater containing sodium hypochlorite into a primary sedimentation tank, add a composite flocculant, and the clarified liquid obtained after the primary sedimentation enters a primary pH adjustment tank for concentration dilution. Then add a primary pH adjuster for homogenization, and when the pH value of the wastewater reaches 4-5, discharge it into a primary treatment tank for primary treatment, and then transport it to a secondary pH adjustment tank, discharge the wastewater into a secondary treatment tank, add a composite reducing agent for secondary sedimentation; the wastewater after the secondary sedimentation enters the catalyst from the top through a water pump, and circulates multiple times in the catalyst; finally, adjust the pH of the wastewater to neutral and then discharge it. This invention realizes the purification of wastewater containing sodium hypochlorite, and the treated wastewater fully meets the standards and can be discharged.

[0006] However, existing sodium hypochlorite wastewater treatment equipment is mainly adjusted and controlled manually, which not only increases labor costs, but also fails to guarantee the reliability of wastewater treatment and poses a risk of environmental pollution. Summary of the invention

[0007] In view of the above technical problems, the utility model provides a dechlorination and salt evaporation system for sodium hypochlorite wastewater, which uses an automatic control system to achieve the metered addition of drugs, the detection of free residual chlorine in the solution and environmental parameters, and improves the stability and intelligence of sodium hypochlorite wastewater.

[0008] In order to achieve the above-mentioned purpose, the utility model provides a dechlorination and salt distillation system for sodium hypochlorite wastewater, wherein a general controller is connected to a dosing device, the dosing device is connected to a reactor, the reactor is connected to a pH regulating tank via a reaction liquid flow pipeline, the pH regulating tank is connected to a suspended basket evaporator via an acidified liquid flow pipeline; the dosing device is also connected to a pH regulating tank pipeline.

[0009] Preferably, the dosing device comprises a dosing module and an acid module.

[0010] Further preferably, the dosing module is connected to the reactor pipeline, and the acid module is connected to the pH adjustment tank pipeline.

[0011] Furthermore, the dosing module and the acid module are respectively provided with a first dosing metering pump and a second dosing metering pump.

[0012] Preferably, the reactor is connected to a tail gas treatment device, and the tail gas treatment device is connected to a pH adjustment tank.

[0013] Preferably, the master controller is also connected to the monitoring device and the valve control device respectively.

[0014] Further preferably, the valve control device is connected to the first valve, the second valve and the third valve respectively.

[0015] More preferably, the first valve is located on the reaction liquid flow pipeline, the second valve is located on the acidified liquid flow pipeline, and the third valve is located on the reactor liquid inlet pipeline.

[0016] Further preferably, the monitoring device includes a first monitor and a second monitor, which are respectively arranged in the reaction kettle and the pH adjustment tank.

[0017] Preferably, the master controller is a PLC controller.

[0018] The beneficial effects of the utility model are:

[0019] 1. The automatic control system - the master controller is used to realize real-time monitoring of the free residual chlorine content of the solution in the reactor, pH adjustment tank and hanging basket evaporator, so as to calculate the amount of medicine that the dosing module and the acid module in the dosing device need to add to the reactor and pH adjuster respectively, and then control the amount of medicine added by controlling the dosing metering pump to realize full automation of drug addition, reduce labor costs and errors caused by manual monitoring, improve the intelligence of the system and the stability of sodium hypochlorite wastewater treatment; reduce energy consumption caused by monitoring errors, and improve safety at the same time.

[0020] 2. Use the automatic control system - the main controller to control the first valve and the second valve in the valve control device to control the outflow timing of the solution in the reactor and the pH adjustment tank. The selection of the outflow timing is achieved by real-time monitoring of the free residual chlorine in the solution and the environmental parameters by the first monitor and the second monitor, which reduces the labor cost and the error caused by manual monitoring, improves the processing stability, and has good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0022] Figure 2 It is a detailed connection diagram of the utility model.

[0023] In the figure, 1 is the main controller, 2 is the dosing device, 3 is the monitoring device, 4 is the valve control device, 5 is the reactor, 6 is the tail gas treatment device, 7 is the pH adjustment tank, 8 is the hanging basket evaporator, 9 is the first valve, 10 is the second valve, 11 is the third valve, 12 is the dosing module, 13 is the acid module, 14 is the first dosing metering pump, 15 is the second dosing metering pump, 31 is the first monitor, and 32 is the second monitor. DETAILED DESCRIPTION

[0024] The technical solution of the utility model is further explained below in conjunction with the accompanying drawings and specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the utility model and should not be understood as limiting the utility model. The protection scope of the utility model shall be based on the content recorded in the claims. Any modification or replacement made by a person skilled in the art to the technical solution of the utility model without creative work shall fall within the protection scope of the utility model.

[0025] Example 1

[0026] like Figure 1-2 As shown, a dechlorination and salt distillation system for sodium hypochlorite wastewater, the main controller 1 is connected to the dosing device 2, the dosing device 2 is connected to the reactor 5, the reactor 5 is connected to the pH regulating tank 7 through the reaction liquid flow pipeline, the pH regulating tank 7 is connected to the hanging basket evaporator 8 through the acidified liquid flow pipeline; the dosing device 2 is also connected to the pH regulating tank 7 pipeline.

[0027] Preferably, the dosing device 2 includes a dosing module 12 and an acid module 13 .

[0028] Further preferably, the dosing module 12 is connected to the reactor 5 via a pipeline, and the acid module 13 is connected to the pH adjustment tank 7 via a pipeline.

[0029] Furthermore, the dosing module 12 and the acid module 13 are respectively provided with a first dosing metering pump 14 and a second dosing metering pump 15 , and the dosing metering pumps are used to control the amount of the reagent added to the dosing module 12 and the acid module 13 .

[0030] Preferably, the reactor 5 is connected to a tail gas treatment device 6, and the tail gas treatment device 6 is connected to a pH regulating tank 7, so that the tail gas generated by the reaction in the reactor 5 and the pH regulating tank 7 is recovered and treated.

[0031] Preferably, the master controller 1 is also connected to the monitoring device 3 and the valve control device 4 respectively.

[0032] Further preferably, the valve control device 4 is connected to the first valve 9 , the second valve 10 and the third valve 11 respectively.

[0033] Further preferably, the first valve 9 is located on the reaction liquid flow pipeline to control the liquid in the reactor 5 to flow to the pH adjusting tank 7; the second valve 10 is located on the acidified liquid flow pipeline to control the liquid in the pH adjusting tank 7 to flow to the hanging basket evaporator 8; the third valve 11 is located on the liquid inlet pipeline of the reactor 5 to control the sodium hypochlorite wastewater to enter the reactor 5.

[0034] Further preferably, the monitoring device 3 includes a first monitor 31 and a second monitor 32; the first monitor 31 is arranged in the reactor 5, and the second monitor 32 is arranged in the pH adjustment tank 7, to detect the content of free residual chlorine and environmental parameters in the reactor 5 and the pH adjustment tank 7 respectively.

[0035] Example 2 Operation method

[0036] Sodium hypochlorite wastewater is added to the reactor 5, and then the content of free residual chlorine in the sodium hypochlorite wastewater is detected by the first monitor 31, and the data is transmitted to the main controller 1, and then the dosing module 12 in the dosing device 2 is controlled to transport the drug 1 to the reactor 5, and the addition amount is controlled by the first dosing metering pump 14; the added drug 1 reacts with the sodium hypochlorite wastewater in the reactor 5 to remove chlorine, and the exhaust gas generated during the reaction is transported to the exhaust gas treatment device 6 through a pipeline for absorption treatment.

[0037] When the removal rate of free residual chlorine in the sodium hypochlorite wastewater in the reactor 5 reaches more than 90%, the first valve 9 is controlled to be opened by the main controller 1, and the reacted solution is transported to the pH regulating tank 7. The pH value and other parameters of the solution are detected by the second monitor 32, and then transported to the main controller 1, and then the acid module 13 in the dosing device 2 is controlled to add the drug 2 to the pH regulating tank 7, and the addition amount is controlled by the second dosing metering pump 15 to adjust the pH value and other parameters of the solution in the pH regulating tank 7; the added drug 2 reacts with the solution in the pH regulating tank 7, and the tail gas generated during the reaction is transported to the tail gas treatment device 6 through a pipeline for absorption treatment.

[0038] When various parameters of the solution in the pH adjustment tank 7 meet the standards, the second valve 10 is opened by the main controller 2 to transport the reacted solution to the hanging basket evaporator 8 for evaporation and desalination, and then the salt and the solution are separated to obtain a solution that meets the discharge standards.

[0039] After all the dechlorinated solution in the reactor 5 is transported to the pH adjustment tank 7, the first valve 9 is closed, and the third valve 11 is opened to transport the sodium hypochlorite wastewater to the reactor 5 for dechlorination, thereby improving the utilization rate of the device and the efficiency of sodium hypochlorite wastewater treatment.

[0040] Preferably, the master controller 1 sets the content of free residual chlorine in the reactor 5 at M1-M2. When the monitored value of the free residual chlorine in the reactor 5 is less than M1, the master controller 1 is used to control the suspension of adding the drug 1 into the reactor 5. When the monitored value of the free residual chlorine content is greater than M2, the master controller 1 is used to control the dosing module 11 to add the drug 1 into the reactor 5. When the monitored value of the free residual chlorine content is between M1-M2, the master controller 1 is used to control the feeding module 12 to add the drug into the reactor according to the optimal feeding ratio.

[0041] Preferably, the pH value in the pH adjusting tank 7 is set between 4.0 and 6.8 in the main controller 1. When the pH value in the pH adjusting tank 7 is ≤6.8, the acid module 12 is stopped from adding medicine to the pH adjusting tank 7. When the pH value is greater than 6.8, the second dosing metering pump 15 is turned on to add medicine 2 to the pH adjusting tank to adjust the pH value and other parameters.

Claims

1. A dechlorination and salt distillation system for sodium hypochlorite wastewater, characterized in that: The main controller (1) is connected to the dosing device (2), the dosing device (2) is connected to the reactor (5), the reactor (5) is connected to the pH regulating tank (7) via a reaction liquid flow pipeline, and the pH regulating tank (7) is connected to the suspended basket evaporator (8) via an acidified liquid flow pipeline; the dosing device (2) is also connected to the pH regulating tank (7) pipeline.

2. A dechlorination and salt distillation system for sodium hypochlorite wastewater according to claim 1, characterized in that: The drug-adding device (2) comprises a drug-adding module (12) and an acid module (13).

3. A dechlorination and salt distillation system for sodium hypochlorite wastewater according to claim 2, characterized in that: The dosing module (12) is connected to the reaction kettle (5) via a pipeline, and the acid module (13) is connected to the pH adjustment tank (7) via a pipeline.

4. A dechlorination and salt distillation system for sodium hypochlorite wastewater according to claim 3, characterized in that: The dosing module (12) and the acid module (13) are respectively provided with a first dosing metering pump (14) and a second dosing metering pump (15).

5. A dechlorination and salt distillation system for sodium hypochlorite wastewater according to claim 1, characterized in that: The reaction kettle (5) is connected to a tail gas treatment device (6), and the tail gas treatment device (6) is connected to a pH adjustment tank (7).

6. A dechlorination and salt distillation system for sodium hypochlorite wastewater according to claim 1, characterized in that: The master controller (1) is also connected to the monitoring device (3) and the valve control device (4) respectively.

7. A dechlorination and salt distillation system for sodium hypochlorite wastewater according to claim 6, characterized in that: The valve control device (4) is respectively connected to the first valve (9), the second valve (10) and the third valve (11).

8. A dechlorination and salt distillation system for sodium hypochlorite wastewater according to claim 7, characterized in that: The first valve (9) is located on the reaction liquid flow pipeline, the second valve (10) is located on the acidified liquid flow pipeline, and the third valve (11) is located on the liquid inlet pipeline of the reactor (5).

9. A dechlorination and salt distillation system for sodium hypochlorite wastewater according to claim 6, characterized in that: The detection device (3) comprises a first monitor (31) and a second monitor (32), which are respectively arranged in a reaction kettle (5) and a pH adjustment tank (7).

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