technological difficulties remain because of the relatively long processing times
and large volumes of gas to be treated.
R&D aimed at developing high-performance materials designed to operate in hostile environments is a very large and active area of endeavor worldwide. Given the limited resources of DOE's coal advanced research program in materials, the committee identified a need for this program to focus on key materials development issues for coal-based technologies while leveraging more generic materials developments from other programs.
The preceding review of DOE's coal R&D programs given in chapters 5 through 7 has been used by the committee as a basis for identifying opportunities in materials research specific to coal-based technologies. Three areas have been selected for emphasis and are discussed below: advanced gas turbines; high-temperature, high-pressure heat exchangers; and inorganic membranes. The present discussion is not intended to provide an exhaustive list of materials research opportunities relevant to the coal program but rather to highlight key materials-based enabling technologies critical to the success of DOE programs in advanced clean fuels and advanced power systems.
Many of the advanced coal-based power generation technologies currently being developed incorporate gas turbines (e.g., IGCC, advanced PFBC, direct coal-fired gas turbines, and IFC [indirectly fired cycles]). Thus, gas turbines constitute a key component in advanced coal-based power generation technologies.
The ATS (Advanced Turbine Systems) program, funded under the natural gas component of the FE R&D program budget, aims to develop advanced land-based turbines for natural gas systems but adaptable to coalor biomass-derived fuels. The systems efficiency target using natural gas is greater than 60 percent based on lower heating value (approximately 55 percent HHV equivalent). Many generic materials issues,1 such as increased temperature capability and extended operating lifetime, are being addressed in the ATS program by DOE and industry participants, and related developments for natural-gas-fired turbines should be broadly applicable to turbines using coal-derived fuels. The committee recommends that activities in the FE coal R&D program focus on materials issues specific to the use of coal-derived fuels in advanced turbines.