Technical Experimental On Wetting Absorption Of No_x By Adjusting Oxidizability With Injecting NO₂

Nitrogen oxides are major pollutants in atmosphere, emissions of gases whichcontaining nitrogen oxides can lead to great loss to human beings and the enviroment.In order to discuss the reaction performance and mechanism in the process of absorption,this experiment put forward a technique of removing NO_xby alkali absorption that combinedwith compounding quantitative NO₂,which could control the rate of NO₂/NO_x.Under the condition of oxidiability50%and in NaOH, Na₂CO₃,Ca（OH）₂solutionswhich have higher alkalinity, we did a research on the effect of oxidizability of nitrogenoxides on absorptivity,on the basis of which we seeked the changes of volume fractions ofNO,NO₂and NO_xand the main reactions during absobing course.The results showed that themain reason for the decrease of volume fractions of NO,NO₂and NO_xin the process ofabsorotion lied that after NO had reacted with NO₂changed into N₂O₃which dissolved inwater to form HNO₂and HNO₃,an acid-base neutralization happened between NaOH,Na₂CO₃,Ca（OH）₂solutions and HNO₂and HNO₃.Subsequently, according to the changes of volume fractions of NO,NO₂and NO_x,weinferred the main reactions during absobing course by reducing absorbent, under thecondition of oxidiability50%and in Na₂SO₃and CaSO₃which have lower alkalinity,in orderto study the absorption mechanism occurring in reducing absorption solutions.The resultsshowed that, at the existence of reducing solution,it exhibited a better absoption rate of NO₂than NO; moreover, reduction reaction occuered in the process of aborption,which finalresultants were N₂and N₂O.Ammonia is not only a weak basic solution,but also with reducibility.It is the reasonwhy acid-base neutralization and reduction reaction are found to coexist during absorptioncourse.But different with Na₂SO₃,CaSO₃solution, acid-base neutralization played a dominantrole.This paper also studied the absorption effect and reaction mechanism ofdenitrification by reducing agent solutions with sodium hydroxide—Na₂SO₃-NaOH mixedsolution system.The results showed that, under the condition of oxidiability50%, ability ofremoval NO_xwas more ideal by reducing agent solutions with sodium hydroxide,whichaborption rate could reach76%, and acid-base neutralization and reduction reaction werefound to coexist in its absorbing course; Na₂SO₃-NaOH mixed solution system appeared tobe well at absobing NO₂,but had less significantly effect on NO absorption.Finally,according to the chemical basis and the respective characteristics of desulfurization and denitrification by calcium-based absorbent, we did a feasibility analysison removal of SO₂and NO_xsimultaneously by calcium-based absorbent.