Laboratory Gasification Studies via Partial Oxidation of Biomass Pyrolysis Vapors

Biomass gasification was simulated at the bench scale in a quartz-tube flow reactor by the partial oxidation of biomass pyrolysis vapors in various atmospheres. Small samples of switchgrass were pyrolyzed at two temperatures, 700 degrees C and 1000 degress C and subsequent gas phase reactions were studied at 850 degrees C. The O2 concentration in the reactor was varied between 1% and 10% and incertain experiments steam was added to the atmosphere. The lowest O2 concentration corresponded to enough O2, in addition to the oxygen in the biomass, to provide 30% of the stoichiometric limit to oxidize a 50.5-mg switchgrass sample. The point at which the oxygen was introduced into the reactor was also varied. Partial oxidation of char and volatiles occurred when oxygen was introduced at therear of the reactor so oxygen flowed over the sample. This is referred to as combustion in this paper. Partial oxidation of the volatiles occurred when oxygen was introduced downstream from the sample and was mixed with the biomass pyrolysis vapors. This is referred to as gasification in this paper. A molecular beam mass spectrometer system was used to monitor the products formed at the variousexperimental conditions.