A comparative experimental study of biomass, lignite and hard coal steam gasification

In the paper the results of experimental comparative study on steam gasification of lignite, hard coal and energy crops, such as Spartina pectinata, Helianthus tuberosus L., Sida hermaphrodita R. and Miscanthus X Giganteus in a laboratory-scale fixed bed reactor at the temperature of 700 °C were presented. The effectiveness of steam gasification in terms of gas flows, composition and carbon conversion was tested. The ability of coal and biomass to undergo thermochemical transformations was determined based on their chars reactivities. The tested biomass samples were relatively more reactive but produced less synthesis gas and of lower calorific value. Comparison of the reactivities and other physical and chemical properties of coals and biomass, selected based on the gasification process requirements, with a use of the principal component analysis showed that biomass samples differ from the remaining samples due to the highest content of volatiles, oxygen and hydrogen in a sample and the highest amount of carbon dioxide in produced synthesis gas. Hard coals were characterized by the lowest carbon conversion and reactivities R50 and Rmax. Moreover, the negative correlation between the reactivity and the heat of combustion, calorific value, carbon content in a sample and total gas yield produced in the process as well as a positive correlation between R50 and Rmax and volatiles, oxygen content in a sample and carbon dioxide concentration in produced gas were observed.