This invention relates to a method and apparatus for controlling the
temperature of combustion gases entering a pollution reduction process
when such a process is applied to a steam generator burning fossil fuel
having at least one heat exchanger. Improved operation of the pollution
reduction process is achieved by controlling the temperature of
combustion gases entering such a process through changes in the working
fluid being heated by the combustion gases. This invention is applicable
to all pollution reduction processes as associated with the combustion of
fossil fuels, said processes being sensitive to the temperature of the
combustion gases, said processes typically include NO.sub.X reduction
processes, SO.sub.X reduction processes, and any pollution reduction
process which employs a catalysis.