CN1194176A - New technology for absorbing and eliminating sulfur dioxide in smoke chemically - Google Patents

Abstract

The new technological process of eliminating SO2 in smoke with ammonia water consists of two parts, the desulfurization and the regeneration of desulfurizing agent. It uses the liquid mixture of hydrated ammonia and ammonium sulfite as absorbing liquid to absorb SO2 in smoke and to produce liquid mixture of ammonium sulfite and ammonium bisulfite, and the used liquid mixture is then regenerated by calcium hydroxide for reuse. The whole process consumes only calcium hydroxide, and no precipitate produces in desulfurization, so that it has high desulfurization effect and low cost.

Description

Novel process for absorbing and removing sulfur dioxide in flue gas by using chemical method

The invention relates to a flue gas treatment process, in particular to a novel process for absorbing and removing sulfur dioxide in flue gas by adopting a chemical method.

With the development of industrial production scale, industrial waste gas is discharged in large quantity, acid rain and acid mist are generated in many places, the human health and the biological balance of an ecosystem are directly harmed, and meanwhile certain damage is caused to buildings and ancient cultural relics. The generation of acid rain and acid mist is mainly caused by the sulfur-containing components in the fuel, and a large amount of sulfur dioxide is generated in the combustion process of the fuel. At present, the domestic flue gas desulfurization method mainly adopts lime milk to absorb sulfur dioxide in flue gas, the absorption rate of the sulfur dioxide is low, and the solubility of calcium hydroxide is low, and in addition, calcium sulfite produced in the desulfurization process is precipitated, so that the equipment is complex, the operation is difficult, and the pipeline blockage phenomenon is easily produced, so that the fatal defects of short service life, large investment and the like exist.

The invention aims to provide a novel efficient flue gas desulfurization process with simple process, simple equipment, low investment and low cost.

The desulfurization process provided by the invention comprises two parts of desulfurization and desulfurizer regeneration:

first, desulfurization part

The desulfurization part comprises a plurality of desulfurizers, and desulfurization is carried out by utilizing a forward absorption method;

firstly, absorbing sulfur dioxide in flue gas by absorption liquid consisting of mixed liquid of ammonia water and ammonium sulfite or pure ammonium sulfite solution through a desulfurizer to generate ammonium sulfite and ammonium bisulfite; the two ammonium salt solutions enter a regeneration part; the desulfurized flue gas passes through an ammonia absorption tower to form ammonium sulfite and ammonium bisulfite, and the ammonium sulfite and the ammonium bisulfite are returned to the regeneration part;

secondly, a desulfurizer regeneration part

The desulfurizing agent regeneration part is composed of a plurality of regeneration tanks, absorption liquid from a desulfurizer enters the regeneration tanks, calcium hydroxide is added, the temperature is controlled at 20-70 ℃, the reaction is carried out for 2-6 minutes, and the absorption liquid returns to the desulfurization part immediately after ammonium sulfite is generated; or reacting for 0.1-2 hours under the condition to generate ammonia monohydrate, and filtering to obtain a mixed solution of the ammonia monohydrate and the ammonium sulfite after the reaction is finished, wherein the mixed solution is used as a desulfurizing agent for repeated use.

The desulfurization process disclosed by the invention has high desulfurization efficiency, and does not generate precipitate in the desulfurization process, so that the problem of pipeline blockage does not exist; in addition, the whole equipment is simple, the investment is low, and the desulfurizer can be regenerated and used, so that the flue gas desulfurization cost is low, and the method is suitable for wide popularization and application.

The present invention will be described in detail with reference to specific examples.

FIG. 1 is a process flow diagram of the present invention.

As shown inthe figure, the desulfurization process provided by the invention consists of two parts, namely desulfurization and desulfurizer regeneration; the desulfurization part adopts a desulfurizer, sulfur dioxide in the flue gas is absorbed by a forward absorption method, the absorption liquid can adopt a mixed solution of ammonium monohydrate and ammonium sulfite or a pure ammonium sulfite solution, the absorption liquid of the embodiment adopts a mixed solution of ammonium hydrate and ammonium sulfite, the mixed solution reacts with the sulfur dioxide in the flue gas in the desulfurizer to generate a mixed solution of ammonium bisulfite and ammonium sulfite, and the mixed solution enters the regeneration part; and the flue gas discharged by the desulfurizer enters an ammonia absorption tower, the ammonia absorption tower is used for absorbing ammonia in the flue gas to generate ammonium sulfite and ammonium bisulfite, the ammonium sulfite and the ammonium bisulfite are returned to a regeneration part, and finally the flue gas without sulfur dioxide is emptied. The chemical equation for the above reaction is as follows:

and (3) introducing the absorption liquid from the desulfurizer into a regeneration tank, adding calcium hydroxide into the regeneration tank, controlling the temperature at 50 ℃, and reacting for 1 hour. The reaction formula is as follows:

this step of the reaction can completely and completely produce ammonium sulfite.

The conversion rate of the monohydrate ammonia generated by the reaction in the step can reach 90 percent.

After the reaction is finished, filtering to obtain mixed liquid of ammonium monohydrate and ammonium sulfite, and reusing the mixed liquid as a desulfurizing agent.

Claims (1)

1. A high-efficiency flue gas desulfurization process is characterized in that: it is composed of two parts of desulfurization and desulfurizer regeneration:

first, desulfurization part

The desulfurization part comprises a plurality of desulfurizers, and desulfurization is carried out by utilizing a forward absorption method;

firstly, absorbing sulfur dioxide in flue gas by absorption liquid consisting of mixed liquid of ammonia water and ammonium sulfite or pure ammonium sulfite solution through a desulfurizer to generate ammonium sulfite and ammonium bisulfite; the two ammonium salt solutions enter a regeneration part; the desulfurized flue gas passes through an ammonia absorption tower to form ammonium sulfite and ammonium bisulfite, and the ammonium sulfite and the ammonium bisulfite are returned to the regeneration part;

secondly, a desulfurizer regeneration part

The desulfurizing agent regeneration part is composed of a plurality of regeneration tanks, absorption liquid from a desulfurizer enters the regeneration tanks, calcium hydroxide is added, the temperature is controlled at 20-70 ℃, the reaction is carried out for 2-6 minutes, and the absorption liquid returns to the desulfurization part immediately after ammonium sulfite is generated; or reacting for 0.1-2 hours under the condition to generate ammonia monohydrate, and filtering to obtain a mixed solution of the ammonia monohydrate and the ammonium sulfite after the reaction is finished, wherein the mixed solution is used as a desulfurizing agent for repeated use.