Modeling syngas-fired gas turbine engines with two dilutants

Computer models were created to contrast cycle performance and turbine designs between air and CO2-diluted GTE cycles fired with syngas fuels. These studies were motivated by concerns about greenhouse gas emissions and the continuing use of coal. These concerns have led to a need for research with a focus on reducing or eliminating carbon dioxide emissions by incorporating recycling and sequestration. Additionally, the advent of gasification technology to produce syngas from coal has increased interest in the use of alternative fuels in power generation cycles.The simple cycle, conventional regeneration, and two alternative regeneration cycles were examined. CO2-diluted simple cycle efficiencies were approximately 5 percentage points lower than the air-diluted simple cycle efficiencies. However, CO2-diluted regeneration cycles showed efficiencies about 2 percentage points higher than the air-diluted cycles. Turbine design models examined for each cycle showed that blades for CO2-diluted flows are shorter than for air diluted cycles. Finally, for CO2-diluted cycles with a closed exhaust-recycling path, an optimum CO2-recycle pressure was determined for each configuration. This pressure was significantly lower than atmospheric pressure for each cycle and ranged from zero to 40 kPa (6 psia). Closed regeneration cycles achieved efficiencies greater than 60% at these optimum recycle pressures.