Combined desulfurization and denitrification method implemented by using metallurgical slags

A metallurgical waste residue, desulfurization and denitrification technology, applied in the environmental field, can solve problems such as the need for catalysts, difficulties in industrial scale-up, and ammonia leakage

CN104826481AInactive Publication Date: 2015-08-12INST OF PROCESS ENG CHINESE ACAD OF SCI
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2015-08-12
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention provides a combined desulfurization and denitrification method implemented by using metallurgical slags. In the method, absorbent slurry prepared by using metallurgical slags and additives as raw materials is adopted, the absorbent slurry in an absorption tower, from top to bottom, is in countercurrent contact with flue gas from the bottom of the tower so as to complete the absorption of SO2 and NOx, the absorbent slurry after absorbing SO2 and NOx enters the absorption tower to carry out cyclic utilization, and then purified gas discharged from the absorption tower is demisted and the like, so that the obtained gas can be directly discharged, and an effect that the removal rate of SO2 is over 96% and the removal rate of NOx is over 73.5% is achieved. The method disclosed by the invention integrates desulfurization and denitrification, so that the running cost is reduced; the main component of an absorbent is metallurgical slags, so that the raw material cost is low; and the additives and the metallurgical slags are mixed for forming the absorbent slurry, so that the effects of desulfurization and denitrification, especially denitration are enhanced, therefore, the method has good economic benefits and a broad industrial application prospect.
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Description

technical field

[0001] The invention belongs to the field of environment, and relates to a combined desulfurization and denitrification method, in particular to an absorbent slurry made of metallurgical waste residue and additives to simultaneously efficiently remove SO from flue gas 2 and NO x Methods. Background technique

[0002] More than 90% of NO in my country x and SO 2 Smoke from coal combustion has caused serious environmental pollution, such as acid rain and dust. Therefore, the desulfurization and denitrification of coal-fired flue gas is one of the important goals of controlling environmental pollution.

[0003] Related patents have been published on the technology of combined desulfurization and denitrification. CN 104014232A discloses a method for flue gas desulfurization and denitrification using urea co-production technology. The method uses urea to prepare ammonia and melamine at a temperature of 200-260°C. Both can desulfurize and denitrify, and the de...

Examples

Embodiment 1

[0063] In this embodiment, the metallurgical waste slag is selected from the converter steel slag produced in the steelmaking process, wherein the content of calcium oxide is 34wt%, and the simulated flue gas NO x (as NO) the content is 1000mg / Nm 3 , SO 2 Content at 400mg / Nm 3 , the oxygen content is about 5% (by volume).

[0064] (1) Prepare absorbent slurry: grind the steel slag to below 100 mesh, add water and stir in the batching tank to form a slurry, the content of steel slag is 1wt%, the stirring time is 5h, add sodium hypochlorite (0.3wt%) and hypochlorite Sodium bicarbonate (0.2 wt %) forms absorbent slurry;

[0065] (2) The flue gas enters the absorption tower 2 from the bottom of the absorption tower 2 after being pressurized by the centrifugal fan 1, and the absorbent slurry prepared in step (1) enters the absorption tower 2 from the top of the absorption tower 2 and flows countercurrently with the flue gas Contact, the temperature of the absorption tower 2 is ...

Embodiment 2

[0071] In this example, metallurgical waste slag is selected from blast furnace slag, in which the content of calcium oxide is 45wt%, and the simulated flue gas NO x(as NO) content at 500mg / Nm 3 , SO 2 Content at 2000mg / Nm 3 , the oxygen content is about 5% (by volume).

[0072] (1) Prepare absorbent slurry: grind the blast furnace slag to below 100 mesh, add water and stir in the batching tank to form a slurry, the blast furnace slag content is 30wt%, the stirring time is 7h, add potassium permanganate (2.5wt %) and hydrogen peroxide (0.5wt%) form absorbent slurry;

[0073] (2) The flue gas enters the absorption tower 2 from the bottom of the absorption tower 2 after being pressurized by the axial flow fan 1 with adjustable vanes, and the absorbent slurry prepared in step (1) enters the absorption tower 2 from the top of the absorption tower 2 And contact with the flue gas countercurrently, the temperature of the absorption tower 2 is controlled at 40-100°C; the liquid-ga...

Embodiment 3

[0079] In this example, the metallurgical waste slag is selected from the electric furnace refining slag produced in the steelmaking process, in which the calcium oxide content is 40wt%, and the simulated flue gas NO x (as NO) the content is 1000mg / Nm 3 , SO 2 Content at 1000mg / Nm 3 , the oxygen content is about 5% (by volume).

[0080] (1) Prepare absorbent slurry: grind the electric furnace refining slag to below 100 mesh, add water and stir in the batching tank to form a slurry, the content of the electric furnace refining slag is 15wt%, and the stirring time is 6h, adding calcium hypochlorite ( 8wt%) to form absorbent slurry;

[0081] (2) The flue gas enters the absorption tower 2 from the bottom of the absorption tower 2 after being pressurized by the movable blade adjustable axial flow fan 1, and the absorbent slurry prepared in step (1) enters the absorption tower 2 from the top of the absorption tower 2 And contact with the flue gas countercurrently, the temperatur...