This project will provide researchers with an improved mechanistic understanding of factors governing the performance of high-temperature abradable seals and degradation mechanisms unique to coal-derived syngas and high-hydrogen content (HHC)-based combustion environments. The ultimate goal for the research effort is to develop a knowledge base to support the design of coatings that retain optimal sealing characteristics and are more resistant to wear/attack mechanisms.
The project objectives are to investigate the impact of coal-derived syngas combustion environments on the performance, durability, and degradation of existing abradable coatings used on turbine shroud structures, and assess the potential for alternative materials sets to improve the performance of hot-section abradable seals in integrated gasification combined cycle (IGCC)-based gas turbine power plants. The proposed program will investigate several classes of abradable coatings (including metal and ceramic-based systems currently being utilized) under simulated exposures to syngas-based combustion environments to determine their relevant wear/abrasive recession behavior, hardness, stability under cyclic oxidation, and general thermo-mechanical behavior. The research is focused on correlating the measured thermo-mechanical behavior and controlled abrasive wear with the intrinsic properties of the multilayer coatings, process-controlled microstructural features, and service environment exposures.
Program Background and Project Benefits
Turbines convert heat energy to mechanical energy by expanding a hot, compressed working fluid through a series of airfoils. Combustion turbines compress air, mix and combust it with a fuel (natural gas, coal-derived synthesis gas [syngas], or hydrogen), and then expand the combustion gases through the airfoils. Expansion turbines expand a working fluid like steam or supercritical carbon dioxide (CO2
) that has been heated in a heat exchanger by an external heat source. These two types of turbines are used in conjunction to form a combined cycle— with heat from the combustion gases used as the heat source for the working fluid— improving efficiency and reducing emissions. If oxygen is used for combustion in place of air, then the combustion gases consist mostly of carbon dioxide (CO2
) and water, and the CO2
can be easily separated and sent to storage or used for Enhanced Oil Recovery (EOR). Alternatively, the CO2
/steam combustion gases can be expanded directly in an oxy-fuel turbine. Turbines are the backbone of power generation in the US, and the diverse power cycles containing turbines provide a variety of electricity generation options for fossil derived fuels. The efficiency of combustion turbines has steadily increased as advanced technologies have provided manufacturers with the ability to produce highly advanced turbines that operate at very high temperatures. The Advanced Turbines program is developing technologies in four key areas that will accelerate turbine performance, efficiency, and cost effectiveness beyond current state-of-the-art and provide tangible benefits to the public in the form of lower cost of electricity (COE), reduced emissions of criteria pollutants, and carbon capture options. The Key Technology areas for the Advanced Hydrogen Turbines Program are: (1) Hydrogen Turbines, (2) Supercritical CO2
Power Cycles, (3) Oxy-Fueled Turbines, and (4) Advanced Steam Turbines.
Hydrogen turbine technology research is being conducted with the goal of producing reliable, affordable, and environmentally friendly electric power in response to the Nation's increasing energy challenges. NETL is leading the research, development, and demonstration of technologies to achieve power production from high hydrogen content (HHC) fuels derived from coal that is clean, efficient, and cost-effective; minimize carbon dioxide (CO2
) emissions; and help maintain the Nation's leadership in the export of gas turbine equipment. These goals are being met by developing the most advanced technology in the areas of materials, cooling, heat transfer, manufacturing, aerodynamics, and machine design. Success in these areas will allow machines to be designed that have higher efficiencies and power output with lower emissions and lower cost.
The University of California at Irvine will provide researchers with an improved mechanistic understanding of factors governing the performance of high-temperature abradable seals and degradation mechanisms unique to coal-derived syngas and high-hydrogen content (HHC)-based combustion environments. The ultimate goal for the research effort is to develop a knowledge base to support the design of coatings that retain optimal sealing characteristics and are more resistant to wear/attack mechanisms. This improved knowledge will ultimately result in better seal design, reduced leakage, and reduced costs through increased performance and efficiency.