Flue gas desulfurization and denitration method

Abstract

The present invention discloses a flue gas desulfurization and denitration method. The method comprises the following steps that: ozone is introduced to a flue gas pipeline with a temperature of 50-200 DEG C, wherein a molar ratio of the ozone to the NOx is 1-3:1; the flue gas mixture after the reaction enters a water washing tower, and is subjected to counter current contact with water to carry out quenching, wherein a volume ratio of the water to the flue gas is 0.002-0.003:1; the water-washed flue gas enters a SO2 absorption tower, and contacts with an absorption agent, wherein the temperature of the SO2 absorption tower is 40-65 DEG C, the volume ratio of the absorption agent to the flue gas is 0.25-0.5:1000; the absorption agent absorbing the SO2 enters a regeneration tower to carry out regeneration; the regenerated absorption agent is recycled, and the purified flue gas is discharged to atmosphere by a chimney.

Description

Technical field: [0001] The invention relates to the separation of sulfur dioxide and nitrogen oxides in flue gas, in particular to a method for removing sulfur dioxide and nitrogen oxides from flue gas. technical background: [0002] Contains SO 2 , A large amount of emission of NOx exhaust gas has caused serious environmental pollution problems, the current control of SO 2 , NOx and other harmful gas emissions is the flue gas purification treatment. At present, flue gas simultaneous desulfurization and denitrification technologies mainly include oxidation absorption, complexation absorption, and reduction absorption. Oxidation absorption technology uses high-energy activation, oxidant oxidation, and catalytic oxidation to reduce NOx or simultaneously reduce SO 2 And NOx is oxidized to a high-valence state, which is easy to absorb oxides, and then absorbed by absorbents. High-energy activation includes electron beam irradiation and pulsed corona plasma. This method has a...

AI Technical Summary

Problems solved by technology

Oxidative absorption is the use of oxidizing agents such as HClO 3 to NOx or simultaneously to SO 2 Oxidation with NOx, and then absorbing with absorption liquid, this method has a high removal rate, but mostly uses strong oxidants, the cost is high, and it is difficult to treat waste liquid or recycle by-products

Catalytic oxidation absorption is the use of catalysts such as activated carbon to convert SO 2 And NOx is oxidized to a high valence state and absorbed by the absorption liquid. The by-products of this method can be recycled, no waste is generated, and the operation is simple, but the treatment volume is small, the land occupation is large, and the catalyst regeneration is difficult.

The complexation absorption method uses iron complexing agent for complexation and desorption to treat flue gas, but the regeneration of complexing agent is difficult, and the secondary wastewater is difficult to treat

The reduction absorption method is a urea and additive method, which reduces NOx to nitrogen and produces ammonium sulfate as a by-product. However, this method has disadvantages such as low removal rate, large amount of reagents, and high cost.

There are also the urea catalyst method and the ethylenediamine cobalt urea method derived from this, using a catalyst to convert SO 2 And NOx is oxidized and then absorbed by urea to obtain by-products ammonium nitrate and ammonium sulfate. Although the removal rate of these technologies is improved and the amount of reagents is reduced, there are difficulties in product recovery and utilization, and the product quality is easily affected after adding additives. Complexity

To sum up, it can be seen that the existing flue gas simultaneous desulfurization and denitrification technology has problems such as high investment and operation costs, small processing capacity, large floor area, complex process, and difficulty in recycling by-products. By-products cannot be well utilized, and more direct Abandoned, resulting in a waste of sulfur dioxide resources

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