to maintain a constant pressure. In this recirculation loop shall be located a heat exchanger to cooldown the circulating ammonia solution. The heat exchanger shall be supplied by cooling water;• In order to get a good reagent/flue gas mixture, ammonia shall be evaporated before being mixed withthe main flue gas stream, updraft the SCR reactor. In addition to this evaporator, the supplier shallinstall a static mixer, at the inlet of the SCR, in order to ensure a perfect homogeneity.• The ammonia injection shall be controlled by the NOx measurements located at the boiler outlet andat the SCR reactor outlet, while respecting the NH 3 leak limitation at the stack outlet. The regulationmode shall minimize the NOx and NH 3 concentrations fluctuations at the stack outlet;• Both ammonia and flue gas pipes are insulated to prevent freezing in cold weather.3.7.2. Flue gas outlet conditionsThe expected flue gas conditions at the outlet of the SCR system (i.e. at the outlet of the flue gas / flue gasheat exchanger) are: