The varying load directly affects flue gas flow field distribution at denitration reactor inlet,this negative effect raises the amount of ammonia escape and makes air preheater be blocked.To solve this problem,field ammonia-injection optimization experiments were conducted on the SCR device of a 600 MW unit in a power plant,and the parallel experiment at 320 MW load was performed to verify the optimization effect.The results show that,after the field ammonia-injected optimization,the distribution uniformity of NOx volume fraction at the inlet and outlet of both reactor A and B was dramatically improved,where the relative standard deviation reduced respectively from 27.8％ to 16.2％ and 20.2％ to 14.6％.The average ammonia escape concentration on both sides of the reactor reduced by 63.6％ and 64.3％ respectively under conditions with slight change of denitration efficiency and NH3/NO ratio,which indicates an obvious optimization effect.However,in the parallel experiment,it was observed that the uneven distribution of NOx concentration at the SCR reactor outlet was still not be fairly improved,the relative standard deviation υk increased,and the denitration efficiency was lower than that under 600 MW when the NHs/NO ratio stayed constant.Compared with the theoretical analysis,the denitration efficiency measured at field test was relatively low.It was suggested that the rectifier device at the denitration system inlet flue be optimized to realize uniform flow field,thus to improve the NOx distribution uniformity at the denitration system outlet,reduce the ammonia escaping rate,and increase the denitration efficiency.
flue gas de-NOxload changeSCRammonia injected optimizationammonia escapeuneven flow fielddenitration efficiency
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