An incineration plant has a heat exchanger (23) arranged in the flow of flue gas, a heat transfer medium circuit (25, 26, 27, 28) for absorbing the heat from the heat exchanger (23) in the flue gas flow and at least one heat exchanger (16, 18) in the heat transfer medium circuit for absorbing the heat from the heat transfer medium circuit. Air may be used as heat transfer medium in the heat transfer medium circuit. The heat exchanger is placed in the flue gas flow downstream of a, for example catalytic, nitrogen oxide reduction stage (21) and upstream of a flue gas dust collector (37). This heat exchanger is used for preheating feed water and/or condensate.