Converting Waste Agricultural Biomass into a Resource - UNEP

Biomass-based Cogeneration Plant
Tanzania, Commercial
Crop
Residue
Process
Sugar Cane
Bagasse
Cogeneration
Equipment
Main Product
Fuel
Technical Description of Technology
The simplest plant setup of a Bagasse Cogeneration plant (see Figure 1)
involves the installation of a boiler producing higher steam pressure than
required for the process. This steam is passed through a steam turbine where
some of the energy is used to generate mechanical power for driving an
alternator for electricity. The steam exits the turbine at a reduced pressure
and is then returned to the boiler as condensate or hot water. The primary
objective of the energy system is the production of steam hence the electricity
that is produced is governed by the demand for process steam. In some
cases especially in sugar mills the electricity becomes a primary product when
the steam is excess to requirements such as is the case after milling season.
The turbine would then be a condensing one where the steam is returned to
the boiler without having to pass through the process. Under these
circumstances the plant operates as a bagasse fired power station.
Figure 1. Structure of a Bagasse Cogeneration Plant
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