Development of a prototypical MHD coal combustor

An MHD (magnetohydrodynamic) combustor design concept allows significant reduction of thermal stresses and decouples safety and operational reliability issues is under development. The design is easily scalable to much larger sizes, simplifies combustor maintenance, and is compatible with high-pressure/temperature cooling water. Essential features of the design are that gas pressure is contained by an uncooled shell made of stainless steel and water-cooled panels provide a thermal shield between the combustor gases and the uncooled pressure shell. A test section with 24 cooling panels has been designed and will be tested shortly in a 20 MW_t coal combustor to assess the concept viability. An experimental program is presently being conducted to evaluate the corrosion resistance of potential panel materials in both fire-side and high-pressure water side environment. Sulfur corrosion tests performed at 600°F demonstrated that the relative corrosion rates (relative to corrosion allowances) for dispersion-strengthened Glidcop copper are significantly lower than for low alloy steels, austenitic stainless steels, and nickel-base alloy. This in combination with good thermomechanical properties makes Glidcop the preferred choice for the slagging-stage thermal shield panels