Process and apparatus for removing undesired gaseous constituents from a flue gas

摘要

A process is described for removing undesired gaseous constituents from a flue gas produced in a combustion. In this process, the flue gas is cooled, if required prepurified and if required depleted with respect to SO2. To reduce the energy costs and for improved execution of this process, it is proposed that the pretreated flue gas is heated in at least one heat exchanger and is passed over a catalyst suitable for the conversion of nitrogen oxides, whereupon the purified hot flue gas is passed over at least one additional heat exchanger and is discharged cooled. In the process, NH3 is preferably added to the heated flue gas.