Research On Flow Modeltest Of SCR And The Reaction Of NO_X Alkaline Liquorabsorption

Nitrogen oxide is one of major air pollutants and fixed combustion source is themost important NOXemission sourcein China, so the research of NOXcontroltechnology for fixedemission source has important theoretical significance andapplication value. In this article, the flow and concentration field of SCR plantwasstudied by experiments, which tested the engineering design of SCR. In consideration ofthe deNOx limitation of SCR, A method of NOXabsorptionby alkali solutionwasproposed as the following NOXemission control process and its reaction performanceand mechanism were studied.The flow distribution and the mixture of reducing agent with flue gas have quiteimportant influence on SCR denitrification performance. The physical modelexperiments are effective measures on testing the flow and concentration field.Thisarticle builds similarity criterion, method and procedure for physical model experiments.By the experiments of A and B physical models, this article verifies the reliability ofCFD and engineering design and guides the engineering application. The experimentsresults show that the guide plate, ammonia injection grid and flow distributiongrid havequite important influence on flow field and reducing agentdistribution. When the fluehas to be designed irregularly, guide plate becomes particularly important. During theanalysis of A and B physical modelexperiments, SCR shows many limits in practicalapplication and its denitrification performance is also effected. In order torealizeultra-clean emission, some following methods are needed.A method which uses alkali solutionto absorb NO2based on peroxidation of NOhas been proposed. By building a stirred tank experiment system, thereactionperformance of of NO2and NOXabsorptionby alkali solution was studied. The influenceof alkali solution concentration and temperature, NOXconcentration and oxidizationdegree on the absorption of NO2and NOXwere obtained, and the main reactionmechanism of alkali liquor absorption ofNOXat low NOXconcentration weredetermined. Mechanism analysis also point out that:1) the effect of N2O3in hydrationcan be neglected;2) alkali solution just reacts with those acid formed by NOXhydrationand it cannot react with NOXdirectly. There is no acid in the liquid film.