(560bj) A Novel Approach to Kinetic Modeling of High Temperature CO2 Adsorbents
AIChE Annual Meeting
2019
2019 AIChE Annual Meeting
Catalysis and Reaction Engineering Division
Poster Session: Catalysis and Reaction Engineering (CRE) Division
Wednesday, November 13, 2019 - 3:30pm to 5:00pm
Hydrogen is produced from natural gas (or biomass) by the two-step steam methane reforming (SMR) and the water-gas shift (WGS) reactions. This is an ideal opportunity for sorption-enhanced reaction, in which CO2 is chemically fixed to a suitable substrate, thus driving the equilibrium in the WGS shift step to the right. Lithium-based ceramics, notably Li4SiO4, have been evaluated as potential CO2 sorbents for this purpose. Several different approaches to modify the lithium silicate composition and morphology have been tried to improve the performance as measured by thermogravimetric analysis (TGA). A difficulty in assessing performance has been the lack of adequate models to reduce TGA data to physically significant parameters; the commonly used double -exponential model has no mechanistic basis and yields parameters that have no basis in the physics and chemistry of these materials. In this talk, we show an adaptation of the Ishida and Wen core-shell model that yields physically meaningful reaction rate constants and diffusion coefficients, and show how this information is used to direct our efforts to develop novel high-temperature CO2 sorbent materials.