Reactions of solid carbon are relevant in many important applications such as power generation, propulsion, and fuel/chemical synthesis. These reactions are simultaneously controlled by multiple physical phenomena spanning multiple length scales such as bulk transport of heat and mass through the reactor system, diffusion of heat and mass across the boundary layer surrounding the solid particle, radiation from the solid particles and participating gaseous media, adsorption and desorption of gaseous species on the solid surface and eventually chemical kinetics at the active sites in the solid. Global conditions of temperature, pressure and gaseous species concentration (CO, CO2, H2O and H2) have a significant impact on these particle scale conversion processes. In-situ measurements of these global and local conditions coupled with theoretical modeling are important for understanding and controlling gasification and synthesis processes.;The present work describes Tunable Diode Laser Absorption Spectroscopy (TDLAS) arrangement for CO mole fraction and temperature measurement that can be potentially packaged into a sensor for probing gasification and synthesis environments. Design and development of a laboratory scale, high pressure, optically accessible fixed bed reactor system suitable for studying carbon conversion processes is presented. Experimental results based on TDLAS measurements of biomass char gasification rates with CO2 are reported. Carbon gasification and synthesis reactions in a flame environment are characterized using TDLAS, Thin Filament Pyrometry (TFP), and infrared imaging. Infrared imaging studies of single particle gasification/combustion processes reveal particle conversion dynamics and flame particle interaction in great detail. These studies provide one of the first data sets to quantitatively verify the details of particle scale theoretical models. Spatially resolved particle scale models have been developed and used to understand the experimental results.
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