Steam gasification kinetics of biochar at elevated pressures

A waste product biomass sample was received and charred to produce the biochar sample. The char reactivity experiments were conducted in a high-pressure fixed bed reactor in the temperature range of 700-730 °C. The steam pressure was varied from 1 to 10 bar steam, and the CO and CO₂ products were measured and used to determine the specific reaction rate of biochar. The results showed that the reaction rate increased with conversion, temperature and steam partial pressure. The increase in steam partial pressure had a significant effect on the reaction rate up to 10 bar steam, where it was observed that the formation of CO₂ contributed more to the specific reaction rate than that of CO and that the selectivity of CO₂ increased over the steam pressure range. The use of these kinetic models also determined the activation energy, and the results were found to be consistent with the literature.