Patent ID: 7118721

Claim:
A method for removing pollutants from flue gas with an emission treatment system, the flue gas being generated by a plant having one or more burners located at an inlet end of a vertically extending stack, the stack including a first ID fan disposed therein, the flue gas being discharged through an outlet end of the stack, the emission treatment system including a major component module, inlet ductwork attached to the stack at a first position intermediate the inlet end of the stack and the first ID fan, and outlet ductwork attached to the stack at a second position intermediate the first ID fan and the outlet of the stack, the major component module having an SCR segment, a heat exchanger segment, and a second ID fan, the SCR segment having at least one catalyst unit composed of materials for selectively catalyzing at least one pollutant, the inlet and outlet ductwork providing fluid communications between the stack and the major component module, the method comprising the following steps: closing the stack at a third position intermediate the first and second positions to prevent the flow of flue gas through the first ID fan; drawing the flue gas from the stack through the inlet ductwork and through the major component module with the second ID fan; removing the pollutant from the flue gas with the SCR segment of the major component module to produce a clean flue gas; and discharging the clean flue gas through the outlet ductwork to the stack with the second ID fan.