Patent ID: 8205451

Claim:
A fuel supply system comprising: a water heater assembly configured to heat a flow of water using progressively higher grade heat from a multi-stage heat exchanger arrangement, said multi-stage heat exchanger including a low pressure economizer and an intermediate pressure economizer, said water heater assembly comprising: a first water source heater coupled to the low pressure economizer for receiving a first flow of water from the low pressure economizer, and to the intermediate pressure economizer to transfer heat from a second flow of heated water received from the intermediate pressure economizer to the first flow of water; and a second water source heater coupled to said first water source heater for receiving the first heated water from said first water source heater, said second water source heater configured to heat the first heated water received from said first water source heater; a fuel inlet flow path configured to receive a flow of fuel; and a fuel heater comprising a first flow path coupled in flow communication with said fuel inlet flow path, said fuel heater comprising a second flow path coupled in flow communication with said second water source heater for receiving the first heated water from said second water heater source, said fuel heater configured to transfer heat from the first heated water to the flow of fuel.