A comparison of the economic performances of hybrid pfbc and conventional combined-cycle plants

摘要

A hybrid combined cycle plant burning natural gas in a gas turbine combustor and coal in a pressurised fludiised bed combustor simultaneously has been designed conceptually. It is possible to control the machine in one of three different ways as a result of the manner in which the gas nad steam turbine cycles are coupled. In examining the off-design performance of the plant under the three different control modes, it was observed that the steam turbine control mode, where the gas turbine power was held fixed and the steam turbine power varied to effiect a change in plant output, gave the highest plant thermal efficiencies over the entire load spectrum. This, however, resulted in the highest consumption of natural gas - the more expensive fuel. It was concluded that life-cycle costs analyses would be required to determine the control mode which would give the most economical plant operation. These results have been presented in earlier papers.