High-temperature and low-temperature gas-phase composite desulfurization and denitration method

Abstract

The invention provides a high-temperature and low-temperature gas-phase composite desulfurization and denitration method. The high-temperature and low-temperature gas-phase composite desulfurization and denitration method comprises the following steps: a) introducing flue gas; b) uniformly distributing the flue gas; c) carrying out flue gas turbulence; enabling the flue gas to penetrate through awater layer concentrated at the bottom of a catalytic contactor to realize sufficient contact between the water layer and a spraying solution; d) carrying out desulfurization and denitration treatment, wherein the spraying solution is a water solution containing NaClO and NaOH; e) removing nitric acid and nitrite in water and mixing the water with an ammonium chloride solution. The desulfurizationand denitration method provided by the invention comprises the following steps: firstly, absorbing NO, SO2 and less NO2 in the flue gas by utilizing the water solution containing the NaClO and the NaOH; then transforming the nitric acid and nitrite ions in the water into nitrogen gas through the ammonium chloride solution to be released. According to the high-temperature and low-temperature gas-phase composite desulfurization and denitration method, very good desulfurization and denitration effects can be realized under a high-temperature or low-temperature condition; the desulfurization anddenitration efficiency can reach 95 percent or more; the method has remarkable beneficial effects and is suitable for being popularized and applied.

Description

technical field [0001] The present invention relates to a desulfurization and denitrification method, more specifically, to a high-low temperature gas-phase composite desulfurization and denitrification method. Background technique [0002] Coal-burning flue gas and industrial flue gas contain sulfur oxides and nitrogen oxides, which are the main factors causing environmental and air pollution. Desulfurization and denitration treatment is the process of removing nitrogen and sulfide in flue gas. Among the nitrogen oxides in flue gas, mainly NO and NO 2 , of which NO accounts for about 90-95%. Flue gas denitrification processes mainly include selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR). The gas temperature is high (usually 850-1100°C), so it is not suitable for flue gas denitration treatment at low temperature. Although the flue gas temperature required by the SCR denitrification method is relatively low (usually 300-600 ° C), its cost i...

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Problems solved by technology

However, the system structure of this limestone denitrification method is relatively complicated, the floor area is large, the investment cost is high, and the power consumption is high, and the waste water needs to be treated.

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