(532h) Comparative Study on Red Mud Gasification of Coal/Biomass Mixtures

Comparative
Study on Red Mud Gasification of Coal/Biomass Mixtures

O.
Hietsoi, C. G. Nyendu, F. Battaglia,* and F. A. Agblevor

USTAR
Bioenergy Center, Department of Biological Engineering, Utah State University,
Logan, UT 84322

*Department
of Mechanical Engineering, Virginia Polytechnic Institute and State University,
Blacksburg, VA 24061

Abstract

Coal is one of the
major sources of fossil fuels used for power generation in the USA. Being one
of the most polluting of all fuels, its annual use significantly contributes to
environmental pollution and greenhouse gas emissions. Therefore, coal
gasification is an alternative to mitigate pollutant emissions. Syngas produced
from coal gasification can be used for electricity generation, chemical
feedstocks, or for production of synthetic natural gas. Moreover, blending coal
with biomass allows to control the hydrogen to carbon monoxide ratio, which is
critical in converting syngas into transportation fuels such as gasoline and
diesel by the Fischer-Tropsch process. Herein, in this work, mixtures of
sub-bituminous coal and biomass feedstocks were gasified at atmospheric
pressure in a bubbling fluidized bed reactor at 700?900 °C on sand and red mud.
Three types of biomass were used, mainly corn stover, switchgrass, and poplar.
It was shown that gasification of coal improved with increase in temperature
and addition of biomass feedstock. De-fluidization of the reactor bed was
observed during coal/corn stover gasification on sand at 900 °C due to formation
of clinker-like material. Notably, gasification using the red mud improved
gasification of the mixture compared to the baseline. The addition of biomass
to the coal appeared to suppress the production of hydrogen but carbon monoxide
yield increased. Additionally, the effect of dry coal/biomass gasification on
red mud has been investigated.