Method for removing metal-like selenium from low-temperature flue gas by sodium salt method

Abstract

The invention discloses a method for removing metal-like selenium from low-temperature flue gas by a sodium salt method. The method comprises the following steps: enabling flue gas to pass through a bed layer taking sodium bicarbonate powder as an adsorbent to perform pyrolysis adsorption oxidation reaction with sodium bicarbonate to pyrolyze the sodium bicarbonate into gapped sodium carbonate with high specific surface area, adsorbing particle-state selenium Sep in the flue gas through the sodium carbonate gaps, and oxidizing element-state selenium Se0 into quadrivalent selenium Se<4+> by anactive oxidation material generated by the oxidation reaction; and feeding the treated flue gas into a spraying tower from the lower part of the spraying tower to completely contact with spraying liquid which is sprayed down from the above and is prepared by adding water into the sodium bicarbonate powder and the sodium bicarbonate powder after pyrolytic adsorption oxidation to perform removing reaction, and removing the quadrivalent selenium Se<4+> and the particle-state Sep and a small amount of element-state Se0 which are not adsorbed and removed from the flue gas. According to the method,the process is simple, the investment and operation expenses are low, the selenium removing rate is high, scaling is avoided during spraying operation, blockage risk is avoided, flue gas fluctuation is insensitive, the condition is easy to change, and other pollutants in the flue gas are easy to remove.

Description

Technical field [0001] The invention relates to the field of environmental protection, in particular to a technical method for removing harmful substances in flue gas, in particular to a method for removing metal-like selenium in low-temperature flue gas by adopting a sodium salt method. Background technique [0002] At present, our country still uses coal as the main energy source, so SO will be generated during the coal combustion process 2 , NO x As well as many pollutants such as heavy metals, metal-like selenium is one of them. According to surveys, the selenium content in coal in my country is about 4 to 5 mg / kg, which is higher than the world average. In addition to the huge amount of coal burned each year, it is roughly estimated that the annual emissions of selenium caused by coal burning in my country are about 2,200 tons. The main reason for the high incidence of selenium poisoning. Therefore, the treatment of metal-like selenium in the flue gas and the suppression of ...

AI Technical Summary

Problems solved by technology

[0008] In view of the current situation and shortcomings of the existing flue gas deselenium technology, the purpose of the present invention is to provide a new method for removing metalloid selenium in low temperature flue gas by using sodium salt, so as to solve the problem that the metalloid selenium in flue gas cannot be obtained. The problem of effective removal has opened up a new method for the recovery and utilization of selenium