Method and device for combined removal of nitric oxide and sulfide in flue gas

Abstract

The invention relates to a method for combined removal of nitric oxide and sulfide in flue gas. The method is characterized by comprising the following steps: spraying gasified ammonia into a furnace of a reaction boiler; reducing NOX in the flue gas to N2 by using a selective non-catalytic reduction method; sending the flue gas into a desulfurization tower; absorbing the SO2 in the flue gas by ammonia water added into the desulfurization tower; and discharging purified gas through a chimney. The invention also relates to a device for combined removal of nitrogen oxide and sulfide in flue gas. The device includes: (A) a combustion boiler used for the combustion of coal and provided with more than one ammonia injection points in the boiler furnace; (B) the desulfurization tower; and (C) an emptying device.

Description

technical field [0001] The invention relates to a flue gas purification technology. In particular, it involves a method for the detection of sulfide and nitrogen oxides (NO X ) and other components of flue gas combined desulfurization and denitrification purification method and purification device. Background technique [0002] Sulfur dioxide (SO 2 ), hydrogen sulfide (H 2 S) and nitrogen oxides (NO X ) is a gaseous pollutant with a large content and a wide range of impacts among air pollutants. They are mainly derived from the combustion process of industrial fuel coal. In large-scale production enterprises such as thermal power plants, metal smelters, and kilns, a large amount of waste gas (commonly known as flue gas) including sulfides and nitrogen oxides will be produced. Sulfuric acid mist, chemical smog, and acid rain formed by sulfur dioxide and nitrogen oxides have brought serious harm to the ecological environment and human production and life. In recent years...

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Problems solved by technology

[0003] At present, coal chemical plants and coal-fired power plants generally adopt the limestone-gypsum method for flue gas desulfurization. This method has the characteristics of high desulfurization efficiency, reliable operation, and high utilization rate of absorbent. The problem of large water consumption and secondary pollution of wastewater

Seawater flue gas desulfurization uses the natural alkalinity of seawater to remove SO from flue gas 2 , this method does not produce waste, the technology is mature and the process is simple, but limited by geographical conditions, it can only be applied to factories in coastal areas

Dry desulfurization includes calcium spraying in the furnace. This method requires less investment, occupies less land, has no sewage and waste acid discharge, and has less equipment corrosion. However, the problems of this method are low desulfurization efficiency, slow desulfurization reaction rate, and prolonged use. Dust collection system needs to be updated

[0006] In view of the problems existing in the above desulfurization and denitrification technologies, many current research directions are to improve the desulfurization efficiency by improving the structure of the desulfurization tower, such as the invention with application number 200820077614. Shaped trays and other structures, but it still fails to fundamentally solve the problem of complex equipment and large investment

The invention with the application number of 200710052131.4 improves the desulfurization efficiency by improving the flue gas intake method, so that the flue gas forms a uniform upward counter turbulent flow in the absorption tower so that the flue gas and the absorption liquid are fully contacted, but this method has an increase in the pressure drop in the tower As a result, the power consumption of the blower is increased and the energy consumption is large.

The invention with the application number 201010606917.8 removes nitrogen oxides in the flue gas by using a low-temperature SCR catalyst moving bed, but the low-temperature SCR catalyst is still in the research and development stage due to its poor resistance to sulfur and water, and it is difficult to be practical in the short term

There are few reports on the systematic joint removal of nitrogen oxides and sulfides

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