Prediction of Gas Turbine On- and Off-Design Performance When Firing Coal-Derived Syngas

Abstract

This paper describes a procedure used to model the performance of gas turbines designed to fire natural gas (or distillate oil) when fired on medium-Btu fuel, such as coal-derived syngas. Results from such performance studies can be used in the design or analysis of Gasification Combined Cycle (GCC) power plants. The primary difficulty when firing syngas in a gas turbine designed for natural gas is the tendency to drive the compressor toward surge. If the gas turbine has sufficient surge margin and mechanical durability, Gas Turbine Evaluation code (GATE) simulations indicate that net output power can be increased on the order of 15 percent when firing syngas due to the advantageous increase in the ratio of the expander-to-compressor mass flow rates. Three classes of single-spool utility gas turbines are investigated spanning firing temperatures from 1985°F-2500°F (1358 K-1644 K). Performance simulations at a variety of part-load and ambient temperature conditions are described; the resulting performance curves are useful in GCC power plant studies.