Method and system for efficiently controlling mercury pollution of coal-fired power plant at low cost

Abstract

The invention discloses a method and system for efficiently controlling mercury pollution of a coal-fired power plant at low cost. The system comprises a primary hot air duct, a secondary hot air duct and a liquid storing tank, wherein the primary hot air duct and the secondary hot air duct are communicated with an air preheater and a hearth; a coal conveying system is communicated with a coal grinding system through a coal feeder; the liquid storing tank is filled with a halide additive solution; and the liquid storing tank is communicated with at least one of the coal conveying system, the coal feeder, the primary hot air duct and the secondary hot air duct. According to the system, the halide additive solution enters a boiler body and participates in a combustion reaction, the oxidation of the mercury in flue gas is promoted and the ratio of mercury oxide in the flue gas is increased, so that the synergetic demercuration effect of flue gas purifying equipment such as denitration equipment, desulfurization equipment, dedusting equipment and the like in a tail flue of a boiler is improved, and the mercury content of flue gas in a chimney is greatly lowered. A mercury pollutant control system has the advantages of small investment and low running cost while the mercury pollutant emission level of the coal-fired power plant can meet stricter environmental standard requirements.

Description

technical field [0001] The invention belongs to the technical field of environmental protection and relates to a pollution control method of a coal-fired power plant, in particular to a high-efficiency and low-cost coal-fired power plant mercury pollution control method and system. Background technique [0002] Mercury is a highly toxic substance that will cause long-term and serious harm to the environment and human body. The global mercury emissions from coal combustion account for about 2 / 3 of the anthropogenic mercury emissions. As a large coal consumption country, China has more severe mercury emissions and pollution caused by coal combustion. Therefore, my country has included mercury pollution control work in the "Twelfth Five-Year Plan for Prevention and Control of Heavy Metal Pollution", and initially proposed that mercury and its compounds emitted by coal-fired power plants must be less than 0.03mg / m 3 emission limit requirements. [0003] At present, a series o...

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Problems solved by technology

The desulfurization system can achieve efficient removal of oxidized mercury, but has little effect on the removal of elemental mercury

The denitrification system can oxidize the elemental mercury in the flue gas, but when the halogen content in the flue gas is low, the oxidation effect is poor

[0007] Therefore, the collaborative mercury removal technology has a better removal effect on oxidized mercury and particulate mercury, but poor removal effect on elemental mercury, especially when the content of halogen in coal is low and the content of elemental mercury in flue gas is high. , the synergistic mercury removal effect of the dust removal device will be significantly reduced

However, the halogen content in coal in my country is generally low, so it may be difficult to obtain a good synergistic mercury removal effect simply by using the existing flue gas purification system

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