Abstract:
Rice straw is a major biomass residue
from rice cultivation, which reaches to a world average
of 740 million tonnes/year generation. Open burning of
rice straw in paddy fields is the common practice, which
could result in an average greenhouse gas emission of 92
kg of CO2 eq/tonne of dry rice straw and other harmful
airborne emissions. Existing studies indicate that
bioethanol production from rice straw is more
environmentally benign, compared to alternative
options, such as gasification for combined heat and
power generation and dimethyl-ether production. This
study analyses the net energy indicators and carbon
footprint of fuel-grade bioethanol production processes
from rice straw comparing three dehydration techniques:
1. Extractive distillation, 2. Azeotropic distillation, and
3. Pressure swing distillation. Chemical process
simulations using the Aspen Plus software were utilized
to evaluate the bioethanol production process from rice
straw, with a plant output capacity of 222 litres/hr of
fuel-grade bioethanol (99.7 vol% ethanol). The results
show that the most environmental benign dehydration
technique is extractive distillation. The findings from
this study can support decision making for future wasteto-
biofuel plants using waste rice straw in the world.
