Desulphurization denitration method for ammonium sulfide solution

Abstract

The invention discloses a desulphurization denitration method for ammonium sulfide solution, and belongs to the technical field of flue gas purification. The method comprises employing an ammonium sulfide solution as an absorbent to absorb sulfur dioxide (SO2) and nitrogen oxides (NOx); performing dust removal and water-washing pretreatment on industrial kiln and furnace flue gas, and blowing proper amount of air into a flue gas pipe, so as to oxidize nitrogen monoxide in the nitrogen oxides into nitrogen dioxide under a slight hot condition, performing two-stage absorption on the flue gas by ammonium sulfide, so as to enable sulfur dioxide and nitrogen oxides in the gas to be absorbed and converted into salts and left in the solution; after the absorption reaction is finished, filtering and recovering sulfur, and performing neutralization, oxidation, evaporation crystallization and drying processing on the filtrate, so as to obtain a solid mixture of ammonium sulfate and ammonium nitrate, wherein the solid mixture can be sold directly as a fertilizer. The method is simple in technology, easy to operate, high in desulphurization denitration efficiency, low in cost and suitable for industrialized application.

Description

technical field [0001] The invention relates to a method for desulfurization and denitrification of an ammonium sulfide solution, and belongs to the technical field of flue gas purification. Background technique [0002] my country's energy is dominated by coal-fired coal, which accounts for 75% of coal production. The raw coal is used for direct combustion. The coal combustion process produces serious pollution, and the sulfur dioxide produced will lead to acid rain. Nitrogen oxides are also one of the causes of acid rain. Human health, under certain conditions, can also destroy the ozone layer and produce photochemical smog. In short, coal-fired smoke is one of the largest pollution sources that cause damage to the ecological environment in our country. my country's energy consumption accounts for 8% to 9% of the world's total, sulfur dioxide emissions account for 15.1% of the world's total, and coal-fired sulfur dioxide emissions account for 87% of the national emissions. ...

AI Technical Summary

Problems solved by technology

There are many problems in the existing desulfurization and denitrification technology, such as the large fixed investment and high desulfurization cost of the limestone-gypsum method, and the large amount of gypsum produced is difficult to handle, etc.; the SCR technology has problems such as large catalyst investment, large influence of flue gas components, and high operating costs. , SNCR technology has a series of problems such as high reaction temperature, poor mixing degree of reducing agent and flue gas, low denitrification efficiency, and large amount of ammonia overflow.

Therefore, the joint desulfurization and denitrification technology has problems such as high fixed investment, high operation and maintenance costs, and complicated operation.

ZL201410290112.5 "A method for flue gas desulfurization and denitrification using urea co-production technology" proposes that the ammonia gas produced by urea co-production technology can be used alone for flue gas desulfurization and denitrification, and the obtained cyanuric acid can also be used alone Flue gas desulfurization and denitrification, ammonia and cyanuric acid can also be combined for desulfurization and denitrification at the same time, ammonia desulfurization, ammonia denitration, cyanuric acid desulfurization, cyanuric acid denitrification are independent of each other, desulfurization The purpose of desulfurization and denitrification can only be achieved by combining the two parts of denitrification. The reaction temperature is between 500 ° C and 1100 ° C. It is also necessary to control the intake ratio of ammonia, cyanuric acid, sulfur dioxide and nitrogen oxides, although the efficiency of desulfurization and denitrification can be improved. , but the operation is complicated and the energy consumption is high

ZL200710052129.7 "Simultaneous desulfurization and denitrification wet ammonia flue gas cleaning process and its system" proposes: first oxidize the nitric oxide in the flue gas to form nitrogen dioxide, and then make the sulfur dioxide and carbon dioxide in the flue gas Nitrogen oxide reacts with ammonia water to generate ammonium sulfite, ammonium nitrate and ammonium nitrite, and then oxidizes the ammonium sulfite and ammonium nitrite to generate by-products ammonium sulfate and ammonium nitrate. At the same time, the flue gas after desulfurization and denitration is processed Eliminate fog and finally obtain clean flue gas. In this invention, nitrogen oxides are absorbed and nitrogen monoxide is produced at the same time, which has the problem of low denitrification efficiency.