Design and evaluation of combined cycle system with solid oxide fuel cell and gas turbine

This study describes the basic design/evaluation of a combined cycle power generation system using solid oxide fuel cells in conjunction with a gas turbine. Factors included are system performance and cost/energy pay-back times (CPT/EPT). Total generation efficiency (Eth) was analyzed from the standpoint of plant size, cell performance, working pressure/temperature, steam carbon ratio, fuel/air utilization ratios (Uf/Ua) and turbine inlet temperature (TIT). A calculation method for determining the system life cycle cost and input energy requirements is also proposed. Results show that Eth is higher than that for conventional power plants; it has a working temperature/ pressure of 1073 K/0.4 MPa, Eth=68.3% with CPT=9.3 years and EPT=0.71 years with load following capability from 60 to 121% nominal load. The main parameters for determining Eth, CPT and EPT were found to be working temperature, cell performance, Ua and TIT limitation. Also discussed in detail are development areas and targets.