-Coal Gasification-
Thomas Westrich and Johannes Schwank
Figure 1. Equilibrium mole fractions for gasification
products (H2, CO, CO2, CH4) and reactants (H2O, C).
Graph courtesy of P. v. Zedtwitz and A. Steinfeld.
Figure 2. Parabolic mirror array
Image courtesy of the TMREC.
"Many experts predict that coal gasification will be at the heart of clean coal technology plants for several decades into the future."
--DOE Coal Gasification R&D Website
Coal gasification uses extremely high temperature (T>1000°C) to decompose coal into syngas (a mixture of hydrogen, carbon monoxide and carbon dioxide); Figure 1 shows the thermodynamic limitations of this conversion. As the temperature increases, production of H2 and CO is favored. Once the temperature exceeds ~830°C, the product gas composition is constant at ~50% H2& CO. In newer, clean coal power plants, coal is gasified into this product gas, which is then burned in air/oxygen to generate heat that can be transformed into electricity through a traditional turbine generator. Improvements to the traditional coal-fired power plants, such as the addition of gasification have dramatically reduced emissions of dangerous compounds (such as NOx's and SOx's) while improving overall plant efficiency.
Further improvements to the gasification reaction would improve overall efficiencies and possibly reduce emissions. Our approach to this problem lies in our experience with hydrocarbon reforming pathways and novel catalyst development for these applications. We aim to apply knowledge gained from reforming of heavy hydrocarbons to increase coal gasification reaction rates. In addition, our research group is interested in developing new gasification reactors, which are aimed at harvesting solar thermal energy through solar concentrators, such as Fresnel lenses or parabolic mirrors (shown in Figure 2).