Abstract:
Biomass torrefaction is a thermochemical pretreatment
process performed at a temperature range of 200oC-
300oC in an inert environment. Moisture and part of the
hemicellulose are released during the process resulting an
energy densified solid fuel. In this study, rubberwood chips
were torrefied at a temperature of 300 oC for 60 minutes. The
results show that the lower heating value of biomass increase
from 14.58 MJ/kg to 16.38 MJ/kg after torrefaction. Further, a
300MWe coal-fired power plant was simulated using Aspen
Plus software and co-firing possibilities of both raw and
torrefied rubber wood were evaluated. The results reveal that
up to 10% of thermal input can be substituted by raw
rubberwood whereas torrefied rubberwood has the potential to
substitute around 20% of thermal input without compromising
the electrical efficiency. The total input mass flow rate is a
crucial factor when co-firing is to be implemented in an
existing plant even though it gives the expected energy output
with a further increase of torrefied biomass share. With
increasing co-firing ratio, it is observed that the total NOx and
SOx emissions are reduced due to low N and S content of
biomass. Further, combustion efficiency is increasing with
increasing co-firing ratio of torrefied biomass.
