Date of Award
Master of Science
The use of air as biomass gasifying agent yields low heating value product gas and is only suitable for heat and power applications. Steam and oxygen gasification on the other hand can increase gas heating value as well as main gas constituents suitable for production of liquid fuels through synthesis processes.
Experiments were carried out to investigate the influence of using oxygen enriched-air and steam mixture as gasifying agents on syngas composition, heating value, fuel-N conversion to ammonia, and NOX emissions during gasification and combustion. The oxygen content in the enriched air was varied from 21% (v/v, atmospheric air) to 45% and 80% on dry basis. On wet basis, the oxygen percentages are equivalent to 30% and 40%. All tests were maintained at fixed bed temperature of 800 yC and steam to biomass ratio (S/B) approximately 0.17. In addition tests were also conducted using three different biomass feedstocks with nitrogen content varying from 0.05 to 1.4 wt%. The NOX emissions from syngas combustion were characterized from different burner operating conditions such as varying heat rates and equivalence ratio.
It was shown that oxygen-enriched air and steam gasification favors the increase of combustible gas components such as H2, CO, CH4 and lighter hydrocarbons and improves the lower heating value of syngas up to 28% and 43% for seed corn and wood, respectively. For all tested biomass feedstocks, results showed that ammonia and NOX concentrations increase as the oxygen percentage in air increase. This, in turn, resulted in higher NOX emissions during combustion.
Cuong Van Huynh
Huynh, Cuong Van, "Performance characterization of a pilot-scale oxygen enriched-air and steam blown gasification and combustion system" (2011). Graduate Theses and Dissertations. 10477.