Method and device for removing mercury in flue gas by utilizing organic wastes

Abstract

The invention provides method and device for removing mercury in flue gas by utilizing organic wastes. The method comprises the steps of: atomizing organic wastes and then spraying into a boiler or a high-temperature region of a kiln hearth to be contacted with flue gas, wherein the content of chlorine in the organic wastes is 35-60mg / L, and mercury in oxychlorinated glue gas form water-soluble mercy chloride capable of being adsorbed on particulate matters, and can be removed through desulfurizing and dedusting processes. The device is connected with the boiler or the high-temperature region of the kiln hearth and comprises an organic waste storage tank, a mud pump, an organic waste pressure-stabilizing tank, an air compressor, an air pressure-stabilizing tank, and a plurality of spray guns, wherein the plurality of spray guns are divided into a plurality of layers and arranged in the boiler or the high-temperature region of the kiln hearth, each spray gun is provided with a liquid joint and a gas joint, the liquid joints are connected with the organic waste pressure-stabilizing tank, the mud pump and the organic waste storage tank sequentially through pipelines, and the gas joints are sequentially connected with the air pressure-stabilizing tank and the air compressor by pipelines. According to the method and device, by removing mercury through organic wastes, treatment of wastes with wastes can be realized, and the running cost for treating wastes and removing mercury in the flue gas can be lowered.

Description

technical field [0001] The invention relates to a method and a device for removing mercury in flue gas by using organic waste, belonging to the technical field of environmental pollution control. Background technique [0002] Mercury and its compounds are very toxic to the human body. Organomercury compounds are the most toxic, especially methylmercury, which has a strong affinity for thiol groups, can combine with many membrane proteins rich in thiol groups in the body, affect protein functions, and lead to toxic effects in multiple systems, mainly 5 Aspects of toxicity: nephrotoxicity, neurotoxicity, reproductive toxicity, immunotoxicity and embryonic and developmental toxicity. [0003] The latest mercury emissions released by the United Nations Environment Program in 2013 show that the global anthropogenic mercury emissions are 2,000 tons per year, and the main sources of emissions are coal combustion and cement kilns, which account for 24% and 9% of the total mercury e...

AI Technical Summary

Problems solved by technology

[0013] There are three deficiencies in activated carbon mercury removal technology: First, the investment and operation costs are high. According to EPA statistics, the average investment of each set of "sorbent injection mercury removal device and bag filter" is 105.9 million US dollars, and the investment amount varies. Range between $38.2 million and $156.2 million, with an average annual running cost of $674,000

Second, after the flue gas is sprayed into the activated carbon, the carbon content in the fly ash increases. On the one hand, it reduces the efficiency of ESP to remove fly ash. On the other hand, the fly ash is difficult to use and landfill, which increases the operating cost and land occupation. Therefore, it is difficult to popularize and apply activated carbon injection mercury removal technology on a large scale.

Third, after the SCR device, due to SCR catalytic oxidation of about 1-1.5% of SO 2 converted to SO 3 , activated carbon adsorbed SO 3 However, the adsorption active sites of Hg are reduced, and the mercury removal efficiency decreases.

[0014] In terms of adding oxidant to improve Hg removal by fly ash and calcium-based sorbent, due to the addition of oxidant to add KMnO 4 、H 2 o 2 , AgNO 3 , halides, etc. are mainly to improve the efficiency of mercury removal, and the main problem is that KMnO 4 、H 2 o 2 As a strong oxidant, it not only oxidizes flue gas Hg 0 , and other reducing substances in the oxidized flue gas, on the one hand, a large amount of oxidant needs to be added, resulting in high operating costs; on the other hand, the equipment is heavily corroded, and long-term operation is difficult

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