There are two main by-products in the sugar milling process:
molasses and bagasse. Bagasse is used as the fuel input to boilers.
Bagasse fired boiler’s steam is used in power turbines to generate
electricity, and the exhaust steam is utilized in the process heating
required for sugarcane milling, distillation and dehydration.
Molasses are converted into anhydrous ethanol fuel (EtOH) from
the route of hydrous ethanol (95% (v/v) ethanol, called rectified
spirit). Fermentation and subsequent repeated distillation processes
of molasses generate rectified spirit. Distillery waste water
effluent (spent wash) is to be treated prior to disposal since
treatment is essential from the environmental point of view.
Anaerobic effluent treatment plant generates biogas, which is later
used as a fuel input to the boilers. Bagasse, which is used to
generate steam for the electricity and the process heat, is
considered as a renewable energy input into the system. Sugarcane
trash, which also has significant energy content, is not considered
in the analysis as open burning before harvesting is a common
practice in Nepal. Energy incurred to produce machineries/
equipment, industrial installations and oil/lubrication in the
factory is also not taken into account in this study.