Abstract:
The increase in conventional fuel prices is bringing fOlWardthe research on alternative
fuels. Running of conventional internal combustion engines using alternative fuels is a
research area where different types of existing engines, used world wide in different
fields of application, are being tried out with different degrees of modifications.
Bangladesh is a low income developing country with some reserves of natural gas and
no oil. With gradual development Bangladesh is facing difficult economic and
technological barriers while trying to meet the increasing power demand of the vast
population. Small-scale petrol generators are widely used to cope-up with the frequent
power failures and load-shedding. This research work investigates the possibility of
using biogas as an alternative fuel for running such small scale power generators. The
use ofbiogas as an alternative fuel in a 1.5 kW portable electric generator run by a SI
engine was studied, keeping engine modifications to a minimum. The biogas was
produced synthetically using a mixture of line supply of natural gas and a regulated
flow of carbon-di-oxide from. a cylinder. The engine performance was studied using
proportional mixtures of the two gases having 55%, 60%, 65% and 70% methane
contents by volume, simulating a range of biogas sources. Maximum output power
was reduced by 20% with biogas having about 60% methane content. The brake
specific fuel consumption rates were comparatively high due to high CO2 content in
biogas but overall peak efficiencies were comparable with petrol. Such performance
with reduced maximum load capacity was only possible if the methane content of the
biogas used was 60% or more. The findings of this study may have potential
significance regarding small-scale power generation in agricultural and poultry firms,
using biogas plants in rural Bangladesh.
