Patent ID: 8528335

Claim:
A system, comprising: a heat recovery steam generator (HRSG); first and second water supplies at first and second relatively high and low temperatures, respectively, the first and second water supplies originating from a common source prior to assuming the first and second relatively high and low temperatures; a heat exchanger, coupled to the water supplies, through which fuel and relative amounts of the water supplies at the first and second temperatures flow for fuel heating, the first water supply being output to the heat exchanger from a component of the HRSG disposed downstream from the common source, and the second water supply being bypassed to the heat exchanger from the common source around the component of the HRSG and fed by an auxiliary water supply at a point between the common source and the heat exchanger; and a controller, operably interposed between the water supplies and the heat exchanger, to select and/or modulate the relative amounts of the water supplies permitted to flow through the heat exchanger to heat the fuel to a temperature based on a heating requirement to meet a modified wobbe index (MWI) rating.