Chlor-alkali denitration strong brine emission reduction process system

Abstract

The utility model discloses a chlor-alkali denitration concentrated brine emission reduction process system which comprises a water inlet tank, original system denitration concentrated water enters the water inlet tank, desalted water is added at the same time, the flow of the original system denitration concentrated water and the flow of the desalted water are controlled by a flow meter, and the diluted water inlet tank is conveyed by a water inlet pump, filtered by a filter and discharged by a water outlet pipe. Under the action of the high-pressure pump, the sodium chloride is increased to proper pressure and enters the membrane device, the membrane device contains a membrane core, so that concentrated water and produced water are obtained, the produced water returns to the salt dissolving pond, and the concentrated water is discharged to the sea. The sodium chloride recycling device can recycle half of sodium chloride, and is short in process, simple to operate and low in operation cost.

Description

Technical Field

[0001] This utility model relates to the field of chlor-alkali denitrification concentrated brine treatment technology, specifically a process system for reducing emissions from chlor-alkali denitrification concentrated brine. Background Technology

[0002] Currently, nanofiltration membrane devices are widely used for denitrification in the chlor-alkali industry. These devices can concentrate sodium sulfate from 10 mg / L to 80 mg / L. The concentrated nitrate wastewater can be treated in several ways:

[0003] In coastal areas where direct discharge into the sea is permissible, concentrated nitrate water containing 80 mg / L sodium sulfate can be discharged directly into the sea. Disadvantage: This concentrated nitrate water contains 180~210 g / L sodium chloride, making direct discharge into the sea too wasteful.

[0004] Places where it is not permissible to discharge into the sea:

[0005] 1. Glauber's salt is obtained by freezing crystallization. This Glauber's salt is waste and poses environmental problems. It is necessary to pay someone else to dispose of it (a common practice in the industry).

[0006] 2. Glauber's salt is obtained by freezing crystallization. The Glauber's salt is then dissolved in hot water or steam and then crystallized by evaporation to obtain sodium sulfate. The cost of sodium sulfate obtained by this method is too high. Although it solves the environmental problem, it is not economically viable (the general practice in the industry).

[0007] 3. Continue to concentrate the sodium sulfate using a high-pressure membrane to 150 mg / L to 160 mg / L. Then, use a salting-out process to precipitate the sodium sulfate and dry it to obtain sodium sulfate.

[0008] Chinese patent discloses a nanofiltration-freeze denitrification process for treating metallurgical wastewater (Publication No. CN109399845 A). This patented technology has the advantages of simple process, easy operation, and low energy consumption. However, sodium chloride recovery is difficult and the operation is complex. Therefore, this utility model provides a process system for reducing concentrated brine emissions in chlor-alkali denitrification to solve the problems mentioned in the background technology. Utility Model Content

[0009] The purpose of this invention is to provide a process system for reducing the emission of concentrated brine in chlor-alkali denitrification, so as to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, this utility model provides the following technical solution:

[0011] A process system for reducing concentrated brine emissions in chlor-alkali denitrification includes an inlet tank. The concentrated denitrification water from the original system enters the inlet tank, along with demineralized water. The flow rates of the concentrated denitrification water and demineralized water are controlled by a flow meter. The diluted water is pumped by an inlet pump, filtered by a filter, and then pressurized to a suitable pressure by a high-pressure pump before entering a membrane device. The membrane device contains a membrane element that can filter and separate sodium sulfate from the brine, thereby obtaining concentrated water and permeate. The permeate is returned to the brine bath, while the concentrated water is discharged into the sea for treatment.

[0012] Preferably, the water inlet tank is equipped with a stirring device to mix and homogenize the water.

[0013] Preferably, the flow rates of the original system denitrification concentrate and desalination water in the inlet tank are the same.

[0014] Preferably, the membrane device contains a different number of membrane shells, and the membrane shells contain a different number of filter cartridges. The filter cartridges can filter sodium sulfate in the brine to ensure that the concentrations on both sides of the sodium chloride are basically the same.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] This invention can recover half of the sodium chloride, and the process is short, simple to operate, and has low operating costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a process system for reducing concentrated brine emissions in chlor-alkali denitrification.

[0018] In the diagram: 1. Inlet tank; 2. Filter; 3. Membrane device; 4. Salt bath. Detailed Implementation

[0019] 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.

[0020] Please see Figure 1 In this embodiment of the present invention, a process system for reducing the discharge of concentrated brine in chlor-alkali denitrification includes an inlet tank 1. The concentrated denitrification water from the original system enters the inlet tank 1, and demineralized water is added at the same time. The flow rates of the concentrated denitrification water and the demineralized water from the original system are controlled by a flow meter, and the flow rates are maintained at 1:1, which is equivalent to diluting the concentrated nitrification water by half.

[0021] After dilution, the water in the inlet tank 1 is pumped by the inlet pump and filtered by the filter 2. Then, under the action of the high-pressure pump, the water is raised to a suitable pressure and enters the membrane device 3. The membrane device 3 contains a membrane core, which can filter and separate sodium sulfate from the brine to obtain concentrated water and permeate. The permeate is returned to the brine tank 4, and the concentrated water is discharged into the sea for treatment.

[0022] The water inlet tank 1 is equipped with a stirring device, which serves to mix and homogenize the water.

[0023] The inlet pump supplies water to the high-pressure pump.

[0024] Filter 2 serves as a safety feature, ensuring that impurities in the water are filtered out to prevent damage to the pump and scratches to the diaphragm.

[0025] The high-pressure pump provides high pressure to overcome the osmotic pressure of the brine filtered through the membrane.

[0026] Membrane device 3 contains a different number of membrane shells, and each membrane shell contains a different number of filter cartridges. The filter cartridges can filter sodium sulfate from the brine, ensuring that the concentration of sodium chloride on both sides is basically the same.

[0027] The working principle of this utility model is as follows: When in use, the original system denitrification concentrate enters the inlet tank 1, and demineralized water is added at the same time. The flow rates of the original system denitrification concentrate and demineralized water are controlled by a flow meter, and the flow rates are kept at 1:1, which is equivalent to diluting the concentrated nitrification water by half.

[0028] After dilution, the water in the inlet tank 1 is pumped by the inlet pump and filtered by the filter 2. Then, under the action of the high-pressure pump, the water is raised to a suitable pressure and enters the membrane device 3. The membrane device 3 contains a membrane core, which can filter and separate sodium sulfate from the brine to obtain concentrated water and permeate. The permeate is returned to the brine tank 4, and the concentrated water is discharged into the sea for treatment.

[0029] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A process system for reducing concentrated brine emissions in chlor-alkali denitrification, comprising an inlet tank (1), characterized in that, The original system denitrification concentrate enters the inlet tank (1), and demineralized water is added at the same time. The flow rates of the original system denitrification concentrate and demineralized water are controlled by a flow meter. After dilution, the inlet tank (1) is transported by the inlet pump and filtered by the filter (2). Under the action of the high-pressure pump, the pressure is increased to a suitable level and enters the membrane device (3). The membrane device (3) contains a membrane core, thereby obtaining concentrate and permeate. The permeate is returned to the brine tank (4), and the concentrate is discharged into the sea for treatment.

2. The process system for reducing concentrated brine emissions in chlor-alkali denitrification according to claim 1, characterized in that, The water inlet tank (1) is equipped with a stirring device.

3. The process system for reducing concentrated brine emissions in chlor-alkali denitrification according to claim 1, characterized in that, The original system denitrification concentrate and desalination water flow rates of the inlet tank (1) are the same.

4. The process system for reducing concentrated brine emissions in chlor-alkali denitrification according to claim 1, characterized in that, The membrane device (3) contains a different number of membrane shells, and the membrane shells contain a different number of filter cartridges.

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