TITLE:
The Properties and Suitability of Various Biomass/Coal Blends for Co-Gasification Purposes
AUTHORS:
Sibongiseni Gaqa, Sampson Mamphweli, David Katwire, Edson Meyer
KEYWORDS:
Gasification, Functional Groups, Thermochemical Process, Coal, Biomass
JOURNAL NAME:
Journal of Sustainable Bioenergy Systems,
Vol.4 No.3,
September
1,
2014
ABSTRACT: Gasification is a
promising technology for the production of gaseous fuels, mainly syngas, which
is produced from the hydrocarbon-based materials such as coal and biomass. Currently, coal is the main feedstock that is used
for the gasification process due to its large reserves and higher energy per
volume. However, the use of coal has been a more concern because of the
environmental impacts caused by the emission of toxic gases such as the
sulphides, sulphates and nitrates as well as the ash slagging problems forming
inside the gasifier. On the other hand, biomass is a renewable energy resource
of interest as a replacement for coal to reduce the environmental impacts associated
with fossil fuel usage. Much
consumption of fossil fuels has caused serious energy crisis and environmental
impacts, globally. Co-gasification of coal and biomass is considered as a
connection between energy production based on fossil fuels and energy
production based on renewable fuels. The utilization of biomass by co-gasification
with coal causes reductions of carbon dioxide, nitrogen and sulfur emissions
due to the renewable character of biomass and low contamination content in
biomass. This study
determined the properties of various biomass/coal blends and their suitability
for co-gasification in a downdraft biomass gasifier. A bomb calorimeter was
used to determine the calorific values of the material. CHNS and XRF analysis
were carried out to determine the elemental analysis of the material.
Thermogravimetric analysis (TGA) was conducted to investigate the thermal
degradation of the material. The kinetic analysis of the various feedstocks allows
the prediction of the rate at which co-gasification takes place. The results
suggested that blending coal with biomass result in a faster reaction rate at
lower temperatures than that of coal alone and lower activation energy due to
the high quantity of volatile matter in biomass.