The increase in the demand for energy caused by the increase in
global industrialization and the rapid rate at which fossil oil reserves
are depleting, as well as issues of environmental concern
with regards to greenhouse gas emissions, have encouraged the
search for alternative energy sources, mainly from renewable resources
such as biomass [1–6]. Biomass provides a clean and
renewable source of energy. Converting biomass to energy rich
products has the potential to be CO2 neutral, as any CO2 produced
during the conversion process is reabsorbed from the atmosphere
by plants [7]. Also the emission level of NOx and SOx from biomass
compared to that of fossil based fuels is almost zero, since biomass
contains very low percentages of N and S [8]. Biomass has been
successfully converted to energy sources such as heat, electricity
and even transportation-grade fuels through both thermochemical
and biological processes [9–11].
Sugar production from sugarcane remains as one of the predominant
agro-industrial activities in South Africa, producing sugar
as the main product and in some instances excess of
electricity after meeting the industry’s energy demand. A substantial
amount of bagasse is generated in this industry during the
milling process (270 kg bagasse/ton of cane milled) according to
Garcia-Perez et al. [12]. Bagasse is the fibrous material that remains
after juice is extracted from sugarcane during the sugar
manufacturing process. It is made up mainly of cellulose, hemicelluloses,
lignin and some small fraction of extractives [2,6,13–16].
Currently bagasse in South Africa just as in many other sugar producing
countries is inefficiently combusted as solid fuel in cogeneration
systems attached to sugar mills to raise steam and generate
electricity to provide the energy demand of the industry [17–19]
leaving very little or no surplus bagasse after meeting mill energy
demand due to the energy intensive nature of the sugar manufacturing
process as well as inefficiencies within the manufacturing