Oak Ridge National Lab Materials

Project Number

FEAA070

Title

Materials Issues in Coal Derived Synthesis Gas/Hydrogen-Fired Turbines

Participant

Oak Ridge National Laboratory

Principle Investigator

Bruce Pint

Project Dates

10/1/2004 - 9/30/2011

Research Area

Materials

Federal Contact

Briggs White – briggs.white@netl.doe.gov

Superalloy blades and vanes in the turbine hot section typically are protected by oxidation-resistant coatings including a thermal barrier coating (TBC) to reduce the metal temperature in service. Turbines fired with synthesis gas from coal are reportedly operated at a lower peak temperature than natural gas-fired turbines to decrease the degradation due to this fuel. However, lowering the peak temperature reduces turbine efficiency, resulting in less electricity generated. The purpose of this study is to better understand the reason for the derating so new materials solutions can be developed to eliminate the derating, increasing the efficiency of coal gasification plants. Currently, the effect of higher water vapor contents on coating performance is being investigated on several different types of coatings. The initial results suggest that some types of coatings are more strongly affected by water vapor than other types. To improve performance in this environment, commercial superalloys with yttrium and lanthanum additions are being investigated to quantify the benefit of these additions on TBC lifetime. High-resolution analytical electron microscopy is being used to locate these elements in the thermally-grown oxides on the coated superalloys. By developing a more complete understanding of the environment and quantifying the benefit of potential solutions, a clearer path toward a solution may be identified.

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