A regenerative selective catalytic reduction process includes providing a gas stream, to be treated containing ΝΟχ, introducing a reactant into the gas stream, and directing the gas stream into contact with a catalyst to cause at least some of the ΝΟχ contained in the gas stream to he reduced, wherein the gas steam is adapted to flow past the catalyst along the same flow direction throughout the process in a substantially continuous manner. The process also includes heating the gas stream with a heater upstream of the catalyst to provide supplemental heat to the gas stream from a first heat exchanger during a first cycle, and to provide supplemental heat to the gas stream from a second heat exchanger using the same heater during a second cycle.
