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 NO_xvolume 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 NO_xconcentration at the SCR reactor outlet was still not be fairly improved

the relative standard deviationυkincreased

and the denitration efficiency was lower than that under 600 MW when the NH3/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 NO_xdistribution uniformity at the denitration system outlet

reduce the ammonia escaping rate

and increase the denitration efficiency.