Developing a novel downdraft fixed bed gasifier for hydrogen production from sawdust to improve an SI engine exhaust emissions

Abstract

The presence of vast forests is the largest source of abundant biomass in Iran. Wood waste can be used as the primary source of energy generation. In the present research, sawdust was employed to produce the syngas. For this purpose, a downdraft gasifier was designed and the produced syngas was evaluated in a spark ignition (SI) engine. Based on results, the production yield of biohydrogen and its heating value at 960 ℃ were about 786 mL/g biomass and 3.75 MJ/m3, respectively. The synthesized syngas compositions were Hydrogen (13.82%), CH4 (1.52%), CO2 (2.75%), CO (13.6%), N2 (65.31%) and water vapor (3%). Increasing the temperature of the combustion zone inside the gasification reactor from 650 to 960 ℃, increased the H2, CH4, and CO contents of syngas. Moreover, the results indicated that, using syngas in engine reduces CO2 and UHC emissions about 58.6% and 16.6%, respectively compared to those for gasoline fuel.