REDUCING THE CONCENTRATION OF OXIDES OF NITROGEN IN A GAS STREAM

摘要

Ammonia is introduced into hot products of combustion leaving a furnace chamber, to reduce the concentration of oxides of nitrogen. A minor proportion of the reacted gas flow is directed to a condenser (24) and the pH of the condensate is measured. The rate of addition of ammonia is controlled according to the measured pH to maintain a small excess of ammonia.