Patent ID: 8691719

Claim:
A method for increasing the active life of an SCR catalyst, the method comprising the steps of: (a) providing at least one coal-based fuel to a furnace, or boiler; (b) subjecting the at least one coal-based fuel to a staged combustion process, wherein the staged combustion process produces at least one gaseous phosphorus compound and/or at least one gaseous phosphorus-containing compound; (c) providing at least one iron-bearing compound to a combustion zone or flue gas stream of the furnace, or boiler, prior to entry of the flue gas into an SCR, wherein the SCR is located upstream of at least one air heater; (d) permitting the at least one iron-bearing compound to react with the at least one gaseous phosphorus compound and/or the at least one gaseous phosphorus-containing compound present in the combustion zone or flue gas prior to the entry of the flue gas into the SCR to form an iron phosphorus-containing compound; (e) providing at least one halide-bearing compound to a combustion zone or flue gas stream of a furnace, or boiler, prior to entry of the flue gas into an SCR, with the proviso that halide-bearing compound is not an iron halide; and (f) permitting the at least one halide-bearing compound to react with and/or oxidize any mercury present in the combustion zone or flue gas, wherein the method achieves an increase in either one, or both, of a catalytic activity and/or a catalytic lifespan of at least about 10 percent at an operational time of at least about 2,000 hours.