Method for removing heavy metal arsenic from low-temperature flue gas by sodium salt method

Abstract

The invention provides a method for removing heavy metal arsenic from low-temperature flue gas by a sodium salt method. The method comprises the following steps: taking sodium bicarbonate with strongoxidation action and adsorption action as a flue gas purification and adsorption oxidizing agent bed layer, adsorbing particle-state arsenic Asp in the flue gas by the pores of sodium carbonate with high specific surface area which is generated through thermal decomposition of sodium carbonate, oxidizing a trivalent arsenic compound in the flue gas by a large amount of active oxidizing substancesgenerated through reaction of the sodium bicarbonate and SO2 in the flue gas to be converted into a pentavalent arsenic compound with high water solubility, enabling the flue gas after oxidation adsorption to enter a spraying tower, performing pyrolysis to adsorb the oxidized sodium bicarbonate and fresh sodium bicarbonate mixed solution spraying liquid and further removing various forms of arsenic from the flue gas so as to purify the arsenic in the flue gas. The method for removing the heavy metal arsenic from the low-temperature flue gas by the sodium salt method, which is provided by the invention, is simple in process, small in investment, low in operating cost and non-corrosive to flue gas purification equipment.

Description

technical field [0001] The invention belongs to the technical field of environmental protection engineering, and relates to a technical method for removing harmful substances in flue gas, and more specifically, relates to a method for removing heavy metal arsenic in low-temperature flue gas by a sodium salt method. Background technique [0002] With the development of the economy, the demand for electricity in industrial production and people's life continues to increase. Although my country is vigorously advocating measures such as energy-saving power generation and the development of new energy sources, my country's coal-based energy structure will not change in a short period of time. Coal is the fossil fuel with the most abundant reserves in my country. However, the combustion of coal produces a large amount of SO x , NO x And heavy metals, among which the more harmful ones include arsenic, mercury, lead, etc., which cause great harm to the ecosystem and human beings....

AI Technical Summary

Problems solved by technology

[0008] The technical problem to be solved by the present invention is to overcome the problem of insufficient activity of the heavy metal arsenic adsorption oxidant in flue gas under low temperature conditions, and to find an adsorption oxidant with good adsorption activity under low temperature conditions, which can efficiently promote the arsenic adsorption in coal-fired flue gas. Trivalent arsenic (As 3+ ) into water pentavalent arsenic (As 5+ ), to solve the arsenic in the flue gas (mainly As 2 o 3 ) is difficult to be captured by traditional technologies. Based on the found adsorption oxidant, a sodium salt method is provided to remove heavy metal arsenic in low-temperature flue gas. This method is simple, low investment, low operating cost, and has no corrosion to flue gas purification equipment.