Performance analysis of a partial oxidation steam injected gas turbine cycle

Partial oxidation gas turbine (POGT) has great potential in improving efficiency because of staged releasing of the chemical energy of fuel. Several researchers have studied the applications of POGT in repowering of different existing power plants. In this study, the POGT is integrated with a steam injected gas turbine (STIG) cycle. This research evaluated the overall thermodynamic performance of a partial oxidation steam injected gas turbine (POSTIG) cycle and investigated the influences of key variables. In addition, comparisons with the STIG cycle were conducted based on exergy analysis. Results show that the combustor outlet temperature of the bottoming gas turbine cycle, the pressure ratio of the bottoming gas turbine cycle compressor, and the temperature of partial oxidation affected the efficiency and specific work output of the POSTIG cycle obviously. Compared with the simple gas turbine cycle, the oxygen concentration in the combustor outlet gas of the POSTIG cycle decreases significantly, and the cooling flow rate increases. Efficiency of the POSTIG cycle is at least two percentage points higher than that of the STIG cycle because of the production and utilization of higher quality steam, along with lower exergy destruction during the graded release of the fuel's chemical energy. - Highlights: • Thermodynamic performance of a POSTIG cycle was evaluated. • The combustor outlet temperature has a great impact on the cycle efficiency. • There exist optimal bottoming gas turbine cycle pressure ratios. • The exergy efficiency of the POSTIG cycle is about 50.648%. • The POSTIG cycle has a higher efficiency than the STIG cycle by at least 2%.