Maximizing the performance of semi-closed oxygen/carbon dioxide gas turbine combined cycles for power generation

The performance of oxy-fuel semi-closed gas turbine power generation cycles has been under investigation in recent years. These cycles have the advantage of capturing and sequestering the carbon dioxide and other pollutants generated by combustion, thus making them zero-emission cycles.; This thesis investigates and compares the performance potential of simple combined cycles and recuperative combined cycles employing state of the art technology. A review of previous literature is also included. The cycles are modeled using a chemically rigorous heat and mass balance simulation tool, ASPEN PLUS 12.1. Investigations include: the effects of fuel gas purity and oxygen purity on working fluid composition; the effects of excess oxygen specification on overall thermal efficiency; the effects of working fluid properties on performance; and the effects of steam injection on performance. Peak performance values are presented for both types of cycle at two levels of oxygen purity. Observations are made on the efficiency and specific work trends.; The developed numerical models were used in combination with general turbomachinery theory to predict the performance of a semi-closed plant based on the Solar Turbines Mercury 50 gas turbine. A single operating point is investigated. The results suggest some modifications to the engine may be required due to improper matching of the turbine to the compressor.