A comparison of biomass gasification and pyrolysis in three kinds of reactors using corn stalk pellets

Biomass resources are abundant in China, the cultivation of which is encouraged as it could provide energy for future social and economic development. Utilization of biomass pellets for energy through gasification could help ease critical problems such as energy shortage and environmental deterioration in China. In this paper, the performance of three types of gasification and pyrolysis reactors-downdraft, bubbling, and pyrolysis-were evaluated in terms of thermal output using the same corn stalk pellets. The three reactors were connected in parallel with a common control system, condenser, root blower, gas tank, and gas chromatography (GC) system. Gas composition was analysed using two GC columns. The lower heating values (LHVs) of the pellets, pellets charcoal, and bio-oil were analysed using a rapid screening device. Analyses of the properties of the pellets and pellets charcoal were carried out using an automatic proximate analyser. In the downdraft reactor, gas with an LHV of 3.91-4.44 MJ/Nm(3) was obtained at a reduction zone temperature (RZT) of 660-760 degrees C. In the bubbling reactor, gas with an LHV of 8.48-9.38 MJ/Nm(3) was obtained at an RZT of 575-750 degrees C. In the pyrolysis reactor, gas with an LHV of 14.51-16.49 MJ/Nm3 was obtained at a pyrolysis temperature of 380-530 degrees C, and pellets charcoal and bio-oil were formed in the pyrolysis reactor as gas-assisted products. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729594]