(383c) High Temperature Gasification of Biochar with Added Methane

Temperatures above 1300°C may be used to increase conversion and synthesis gas quality and decrease carbon dioxide and hydrocarbon formation in an allothermally heated gasifier.  Using methane, or natural gas, as a reactant increases the hydrogen content of the synthesis gas to be compatible with liquid fuel synthesis technologies.  Thermodynamic equilibrium results confirm an adjustable H₂:CO given a variable methane-to-biomass ratio as well as superior utilization of hydrogen and carbon monoxide compared to methane reforming.  Experimental results show that a complex, kinetic-limited relationship exists between char gasification and methane reforming.  Reactions of pyrolysis further complicate experimental controllability of the product gas composition.  Char gasification and methane reforming were modeled in a 1-D plug flow reactor configuration assuming a monodisperse particle  distribution and an entrained particle flow.  Experiments with biochar, methane, and steam were used to obtain global kinetic models of the relevant reactions.  Effects of reactant flow rate, particle diameter, and wall temperature were explored.