Experimental Investigation of NOx Reduction by Urea Solution Injection in Fuel-rich Zone of Coal Combustion

Abstract

Experiments were carried out in an electrically heated vertical tandem-type drop-tube furnace system to evaluate the influence of stoichiometric ratio (SR), normalized stoichiometric ratio (NSR) and temperature (T) on NOX reduction by urea solution in coal combustion. The results indicated that, SR was the deciding factor for NOX reduction by ammonia under high temperatures. The reduction efficiency was inproved with the increase of NSR. There was a significant reduction in NOX emission with increase in temperature under reducing conditions. However, ammonia had the tendency to get oxidized to NO, in presence of excess O2 in the combustion zone at high temperature.