Mercury curing and removing method for coal-fired power plant and device thereof

Abstract

The invention discloses a mercury curing and removing method for a coal-fired power plant. The method comprises the following steps of treating a flue gas by an air preheater after the flue gas is subjected to denitration treatment; conducting electrostatic dust-removal treatment on the treated flue gas, and removing divalent mercury in a sulfide solution; and desulfurizing the flue gas which is subjected to demercuration treatment, and emitting the flue gas. According to the method, the divalent mercury in the flue gas is collected in a mercury collector before the flue gas which is subjected to dust removal by a dust collector enters a desulfurization tower, so that the divalent mercury in the flue gas is prevented from entering desulfurization gypsum, and the mercury content in the desulfurization gypsum is greatly reduced; hazardous waste treatment is carried out intensively after mercury in the collector is enriched, the gypsum quality is prevented from being influenced by the fact that the divalent mercury enters the desulfurization gypsum of the desulfurization system, and the problem of secondary pollution caused by mercury release is avoided at the same time; the mercury collector is arranged before desulfurization, the temperature of the flue gas at the desulfurization inlet can be reduced, and the desulfurization efficiency can be improved; and mercury collected in a mercury collection reactor can be intensively subjected to hazardous waste treatment, so that mercury removal can be truly realized.

Description

technical field [0001] The invention relates to a mercury removal treatment technology, in particular to a mercury solidification removal method and device for coal-fired power plants. Background technique [0002] Mercury is a volatile toxic heavy metal that can stay in the environment for a long time, and if it enters the human body, it will cause serious harm to health. Coal contains mercury, and mercury emissions from coal-fired power plants are one of the main sources of anthropogenic mercury emissions. Mercury mainly exists in three forms in the flue gas of coal-fired boilers: gaseous elemental mercury (Hg 0 ), gaseous divalent mercury (Hg 2+ ) and particulate mercury, Hg 2+ and particulate mercury can be removed by existing pollution control equipment in coal-fired power stations, while Hg 0 Because it is insoluble in water and strong volatility is not easy to be removed, it will pollute the environment after release. At present, there are two main mercury remova...

AI Technical Summary

Problems solved by technology

Mercury mainly exists in three forms in the flue gas of coal-fired boilers: gaseous elemental mercury (Hg 0 ), gaseous divalent mercury (Hg 2+ ) and particulate mercury, Hg 2+ and particulate mercury can be removed by existing pollution control equipment in coal-fired power stations, while Hg 0 Because it is insoluble in water and strong volatility is not easy to be removed, it will cause pollution to the environment after release

At present, there are two main mercury removal technologies: one is to use activated carbon adsorption technology, which has affected the popularization and application of this technology due to high investment costs and problems such as activated carbon regeneration; the other is to use existing environmental protection devices to improve mercury removal. removal efficiency

The main problem of this technology is: the mercury in coal combustion is mainly concentrated in desulfurized gypsum, and the water solubility experiment of desulfurized gypsum shows that the mercury in desulfurized gypsum is basically insoluble in water, and the mercury dissolution rate is about 10%.

Desulfurization gypsum can be used in the construction industry and building materials industry. In the processing process of most desulfurization gypsum reuse processes, there are heating processes such as drying and calcination. Anhydrous gypsum is calcined at high temperature, and at high temperature, mercury and its compounds will be released from desulfurized gypsum and cause pollution to the environment, which also affects the use of desulfurized gypsum

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