THE EFFECTS OF CHANGING FUELS ON HOT GAS PATH CONDITIONS IN SYNGAS TURBINES
- ORNL
Gas turbines in integrated gasification combined cycle power plants burn a fuel gas (syngas) in which the proportions of hydrocarbons, H2, CO, water vapor, and minor impurity levels may differ significantly from those in natural gas. Such differences can yield changes in the temperature, pressure, and corrosive species that are experienced by critical components in the hot gas path, with important implications in the design, operation, and reliability of the turbine. A new data structure and computational methodology is presented for the numerical simulation of a turbine thermodynamic cycle for various fuel types. The approach used allows efficient handling of turbine components and different variable constraints due to fuel changes. Examples are presented for a turbine with four stages. The vanes and blades were considered to be cooled in an open circuit, with air provided from the appropriate compressor stages. A constraint was placed on the maximum metal temperature and values were calculated for the fuel flow rates, airflow ratios, and coolant flow rates for cases where the turbine was fired with natural gas, NG, or syngas, SG. One NG case was conducted to assess the effect of coolant pressure matching between the compressor extraction points and corresponding turbine injection points. It was found that pressure matching is a feature that must be considered for high combustion temperatures. The first series of SG simulations was conducted using the same inlet mass flow and pressure ratios as those for the NG case. The results showed that higher coolant flow rates and a larger number of cooled turbine rows were needed for the SG case to comply with imposed temperature constraint. Thus, for this first case, the turbine size would be different for SG than for NG. In order to maintain the original turbine configuration (i.e., geometry, diameters, blade heights, angles, and cooling circuit characteristics) for the SG simulations, a second series of simulations was carried out in which the inlet mass flow was varied while keeping constant the pressure ratios and the amount of hot gas passing the first vane of the turbine. The effects of turbine matching between the NG and SG cases were increases for the SG case of approximately 7 and 13 % for total cooling flows and cooling flows for the first vane, respectively. In particular, for the SG case, the vane in the last stage of the turbine experienced inner wall temperatures that approached the maximum allowable limit.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- Work for Others (WFO)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 951283
- Journal Information:
- Journal of Engineering for Gas Turbines & Power, Vol. 131, Issue 4
- Country of Publication:
- United States
- Language:
- English
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