Hydrogen-rich gas production from a biomass pyrolysis gas by using a plasmatron

Abstract

Pyrolysis and gasification is an energy conversion technology process that produces industrially useful syngas from various biomasses. However, due to the tars in the product gases generated from the pyrolysis/gasification of biomass, this process damages and causes operation problems with equipment that use product gases such as gas turbines and internal engines.Therefore, in this study, a continuous-screw-type pyrolyzer was manufactured and the plasmatron was connected to its rear end through the pyrolyzer. And experiments were performed according to increasing the tar conversion and the hydrogen yield of the product gas. To conduct the parametric studies, experiments were performed on the variations in the steam feed rate, plasma input power and sawdust feed rate (i.e., change for tar concentration in the product gas) to show the performance of plasmatron. The light and gravimetric tars and gases were analyzed to examine the behavior of the products against the hydrogen-rich gas production and tar destruction from the pyrolysis gas.When the steam feed rate of the plasmatron was 1.0 L/min, the plasma input power was 0.17 kW and the sawdust feed rate to the pyrolysis was 0.7 g/min, the conversion rates of the representative light tar components were 80.9% for benzene, 97.6% for naphthalene, 90.7% for anthracene and 90.6% for pyrene. Furthermore, the conversion rate of gravimetric tar was 99.7%.The reformed gas after the plasmatron reaction contained 9% hydrogen, 8.9% carbon monoxide, 2.8% carbon dioxide, 0.55% methane, 0.07% ethylene, 0.01% ethane and 0.12% propane. The hydrogen increased 87.5%, while carbon dioxide decreased 12.5%.