Catalyst for mercury oxidation and preparation method and purpose thereof

Abstract

The invention discloses a copper-based composite catalyst for gas-state zero valent mercury oxidation in the field of smoke control and a preparation method and the purpose thereof. The copper-based catalyst is a copper-based composite oxide catalyst and/or a copper-based composite halide catalyst. The catalyst can utilize oxygen and trace HCI existing in smoke to achieve high efficiency conversion of zero valent mercury (HgO) and divalent mercury (Hg2+) under low temperature in a wider temperature range (500-300 DEG C) and can even achieve high efficiency oxidation of simple substance mercury in smoke free of HCI. The catalyst is suitable for catalytic oxidation of mercury in fire coal smoke, and the product Hg2+ of oxidation can be easily dissolved in water and can be removed by other pollutant control devices. The catalyst is simple in preparation method, wide in suitable temperature range, high in oxidation efficiency, weak in dependency on CI in the smoke, good in stability and high in SO2 poisoning resistance and has good application prospects and economical benefits in the fire coal smoke mercury discharge control fields including power station boilers, industrial boilers, industrial kilns and the like.

Description

technical field [0001] The invention belongs to the field of flue gas control, and relates to a method for removing mercury by catalytic oxidation. Specifically, the invention relates to a catalyst for oxidizing and removing elemental mercury, its preparation method and its application. Background technique [0002] Mercury (Hg) pollution has become the focus in the field of air pollution control because of its characteristics of persistence, easy migration and high bioaccumulation. my country is a large coal-burning country, and the proportion of coal in the energy structure is as high as 75%. At the same time, the mercury content of raw coal in China is relatively high, the chlorine content is low, and the coal-fired technology is generally backward, resulting in particularly serious mercury pollution. The emission standard of mercury pollutants stipulates that the concentration of mercury in coal-fired flue gas should be less than 30 μg / m 3 . Mercury diffused into the ai...

AI Technical Summary

Problems solved by technology

[0007] However, there are certain defects in the above catalysts, first of all, its space velocity is low, and its space velocity is -1 , the catalytic activity will be reduced when it is enlarged to industrial applications; secondly, there must be oxidant precursors such as HCl in the flue gas, and additional oxidants need to be added to exert a better catalytic effect. In addition, the catalytic effect of the catalyst is poor when the temperature is below 150°C It may be further reduced for industrial applications, that is, it is difficult to achieve efficient oxidation of mercury after dust removal

[0008] The existing oxidative mercury removal catalysts have the following problems: poor activity at low temperature (such as below 150°C), low allowable space velocity, high energy consumption, high cost, and strong dependence on HCl, requiring additional addition of oxidants or oxidant precursors, etc.

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