CN111020631A

CN111020631A - Method for removing ammonium from brine

Info

Publication number: CN111020631A
Application number: CN201910960344.XA
Authority: CN
Inventors: 陈玉林; 姚俊; 郭铭
Original assignee: Jiangsu Meilan Chemical Co ltd
Current assignee: Jiangsu Meilan Chemical Co ltd
Priority date: 2019-10-11
Filing date: 2019-10-11
Publication date: 2020-04-17

Abstract

The invention discloses a method for removing ammonium from brine, which comprises the following steps: the brine entering a factory is discharged into a ground tank, sodium hypochlorite is added in front of a brine pump, the brine is lifted by the pump and sent to a reaction elevated tank, the brine reacts in the reaction elevated tank for 1 to 2 hours, flows down automatically from the top of an ammonium blowing tower, flows through a packing layer, is in countercurrent contact with compressed air conveyed by a fan, is fully blown by the compressed air to remove ammonium and then flows into a salt dissolving water storage tank for salt dissolving. The invention has the advantages of stability, reliability, low operation cost, no three-waste discharge and no pollution to the surrounding environment.

Description

Method for removing ammonium from brine

Technical Field

The invention relates to a method for removing ammonium from brine.

Background

At present, the production hidden trouble caused by accumulation of NCl3 appears in the production process, and the harm to the generation of nitrogen trichloride in the electrolysis process is more and more concerned along with the increase of the proportion of the used brine. The ammonium removal effect of the brine is poor, nitrogen trichloride produced in the production process is enriched in the liquid chlorine vaporizer, and when liquid chlorine packing personnel clean the vaporizer, the nitrogen trichloride in a sewage pipe can explode to cause accidents.

Disclosure of Invention

The invention provides a method for removing ammonium from brine, which is stable and reliable, has low operation cost, basically does not discharge three wastes, and does not cause pollution to the surrounding environment.

The invention adopts the following technical scheme: a method for removing ammonium from brine comprises the following steps: the brine entering a factory is discharged into a ground tank, sodium hypochlorite is added in front of a brine pump, the brine is lifted by the pump and sent to a reaction elevated tank, the brine reacts in the reaction elevated tank for 1 to 2 hours, flows down automatically from the top of an ammonium blowing tower, flows through a packing layer, is in countercurrent contact with compressed air conveyed by a fan, is fully blown by the compressed air to remove ammonium and then flows into a salt dissolving water storage tank for salt dissolving.

When sodium hypochlorite is added, the proportion of sodium hypochlorite is determined according to the ammonium content of brine, the flow is controlled by a flow meter, and the sodium hypochlorite and the brine are uniformly mixed and enter a high-order reaction tank for reaction after being stirred by a pump impeller. Add sodium hypochlorite before the brine pump, go into the reaction elevated tank after with centrifugal pump pressurization misce bene, control reaction time in the reaction elevated tank, let the ammonium fully reaction in hypochlorite root and the brine, form more volatile NHCl2, NH2Cl, by the artesian entering ammonium of reaction elevated tank blow off the tower, contact with the compressed air countercurrent that the bottom air-blower sent, control the wind pressure, ammonium in the desorption brine. And reacting for 1 hour in the reaction elevated tank.

The invention has the following beneficial effects: by adopting the technical scheme, the process can continuously carry out ammonium removal treatment on the brine, the time is short, and the ammonium removal efficiency is greatly improved. After the method is implemented, the index of total ammonium in the refined brine is always very low, the content of inorganic ammonium is not analyzed, and the process index is normal. Not only saves the consumption of the raw salt in the production process, but also eliminates the threat of nitrogen trichloride explosion on the safe production of the chlor-alkali.

Drawings

FIG. 1 is a schematic flow chart of the present invention.

Detailed Description

The technical principle of the invention is as follows: the ammonium removal of brine is to add an ammonium removal agent NaClO aqueous solution or chlorine water into saturated brine to generate NH₂Cl, the reaction equation is as follows: NH (NH)₄ ⁺+OH^-

NH₄OH，NH₄OH

NH₃+H₂O ，NH₃+ClO^-

NH₂Cl+OH^-(ii) a In the process of removing ammonium from brine, the generation of NH must be satisfied₂Cl condition, i.e. pH of brine>And 8, heating properly in the reaction process. The monochloramine generated by the reaction is extremely volatile liquid, the boiling point of the monochloramine is 66-69 ℃, the monochloramine is easily decomposed in aqueous solution, and compressed air is adopted for blowing in the process. In figure 1, the invention discloses a method for discharging brine entering a factory into a ground tank, adding sodium hypochlorite before a brine pump, lifting the brine by the pump to a reaction head tank, reacting in the reaction head tank for about 1 h, flowing down automatically from the top of an ammonium blowing tower, flowing through a packing layer, contacting with compressed air delivered by a fan in a counter-current manner, fully blowing off and deammoniating by the compressed air, and flowing into a brine storage tank for salt dissolving. The technological key points of the invention are that the original sodium hypochlorite is added into a brine pool, the flow of the sodium hypochlorite is controlled by a flowmeter, the proportion of adding the sodium hypochlorite is determined according to the ammonium content of brine, the sodium hypochlorite and the brine are uniformly mixed by stirring of a pump impeller, and the mixture enters a high-level reaction tank for reaction. The reaction is sufficient, the time is short, the ammonium removal efficiency is greatly improved, the continuous treatment of brine can be realized, and the potential safety hazard is eliminated for producing caustic soda by using brine in large quantity. By additionally arranging equipment such as a brine pond, a brine pump, a sodium hypochlorite elevated tank, a reaction elevated tank, an ammonium blowing tower, an air blower and the like, the original brine treatment is discontinuously treated by aeration blowing, and is transformed into continuous treatment. Sodium hypochlorite is added in front of the brine pump, and the mixture is pressurized and mixed uniformly by a centrifugal pump and then enters a reaction elevated tank. Controlling a certain reaction time in the reaction head tank to ensure that hypochlorite fully reacts with ammonium in brine to form easily volatile NHCl2 and NH2Cl, automatically flowing into an ammonium blowing tower from the reaction head tank, and making the ammonium blowing tower and compressed air sent by a bottom air blower contact in a countercurrent manner to control a certain air pressure and remove ammonium in the brine. The mixing amount of the brine is greatly increased, and the removal rate is increased from 80-85% to more than 95%. The method can continuously perform ammonium removal treatment on the brine, has short time and greatly improves the ammonium removal efficiency, saves the raw salt consumption in the production process, and eliminates nitrogen trichlorideThe threat of explosion to the safe production of chlor-alkali.

Claims

1. A method for removing ammonium from brine comprises the following steps:

the brine entering a factory is discharged into a ground tank, sodium hypochlorite is added in front of a brine pump, the brine is lifted by the pump and sent to a reaction elevated tank, the brine reacts in the reaction elevated tank for 1 to 2 hours, flows down automatically from the top of an ammonium blowing tower, flows through a packing layer, is in countercurrent contact with compressed air conveyed by a fan, is fully blown by the compressed air to remove ammonium and then flows into a salt dissolving water storage tank for salt dissolving.

2. The method of claim 1, wherein the sodium hypochlorite is added according to the ammonium content of the brine, the ratio of sodium hypochlorite addition is determined, the flow rate is controlled by a flow meter, the sodium hypochlorite and the brine are uniformly mixed by a pump impeller, and the mixture enters an overhead reaction tank for reaction.

3. The method of claim 1, wherein sodium hypochlorite is added before the brine pump, the mixture is pressurized and mixed by a centrifugal pump, and then the mixture enters the reaction head tank, the reaction time is controlled in the reaction head tank, the hypochlorite and the ammonium in the brine are fully reacted to form relatively volatile NHCl2 and NH2Cl, the volatile NHCl2 and NH2Cl are formed, the volatile NHCl2 and NH2Cl automatically flow from the reaction head tank into the ammonium stripping tower and are in countercurrent contact with compressed air from a bottom blower, the air pressure is controlled, and the ammonium in the brine is stripped.

4. The process of claim 1, wherein the reaction is carried out in the overhead tank for 1 hour.