Comparative study on the gasification performance of two energy crops by steam or carbon dioxide

Abstract

The gasification of two energy crops (Cynara cardunculus L. and Helianthus annuus L.), under steam or carbon dioxide atmosphere, in a fixed bed system was compared. The efficiency of the process was determined in terms of thermal behavior, reactivity, conversion, energy recovery and product gas composition, which was quantitatively analyzed by a mass spectrometer unit. When the steam/biochar ratio increased from 1 to 3, conversion was enhanced and the concentration of H2 in the product gas was raised up to 56 %. The yield of syngas was higher for cardoon fuel and that of CO2 lower, as compared to helianthus fuel. Upon carbon dioxide gasification, helianthus biochar presented a higher reactivity and conversion (80.7 %) than cardoon biochar (64.9 %). Under a steam atmosphere the higher heating value of generated gas was lower, however energy recovery from the two crops was significantly enhanced in relation to carbon dioxide gasification.