Energy Conservation and Efficiency Improvement in Sugar Factories (Case Study: Finchaa Sugar Factory)
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Date
2019-02
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Addis Ababa University
Abstract
Like any industry, the three top operating expenses are often found to be energy (both electrical
and thermal), labour and materials in a sugar factory. Energy has the highest potential for cost
reduction by ensuring energy efficiency and conservation. The energy costs are rising steadily
and availability of fuel is becoming scarce. Electrical energy and thermal energy are the primary
energy types used for sugar processing and the benefits of energy efficiency and conservation are
commonly accepted in the sugar industry. Cogeneration power plants using bagasse in sugar
factories produce steam and electricity for use in the sugar processing and also export the excess
power to the grid. For the generation of excess power there is continuous analysis required for
the economical balance for input and output power. The success of cogeneration depends on
efficient use of energy.
The thesis work tries to identify the way energy is being used, mainly targeted at identifying
practical, sustainable and economically viable energy saving opportunities in different sections
of the factory, i.e. electrical systems, major drive motors, lightings, captive power plants,
resulting from a compressive study and analyses of technical parameters through energy audit
methodology. The study involved using a wide range of sophisticated, portable, diagnostic and
measuring instruments to generate refined data. International Motor Selection and Saving
Analysis (IMSSA) software and RETScreen energy efficiency model tools are used to facilitate
in complex analyses to give a more reliable basis for evaluation of performance, energy saving
measures and economic/financial viability.
The study conducted (energy conservation and efficiency improvement) on electrical systems,
major drive motors and lightings identify recommendations, which identified an annual
electricity saving potential of 4,303MWh. This works out around 15% of the total base case
electricity consumption with fuel cost saving of 77,883 USD Analyzed with RETScreen Energy
Efficiency model. The power quality parameters like voltage unbalance, total harmonic
distortions and frequency are measured at PCC/MCC and compared against the IEEE-519
standard and they are found to be well within the limit, but power factor at some MCC are less
than optimum.The second part of the study focuses on the steam generation and distribution system. The study
conducted in the steam generation unit shows the steam generation units during the study (boiler
1, boiler 3 and boiler 4), have very low efficiency (on average 63.59%) when compared to the
minimum acceptable efficiency of boiler that uses bagasse as a fuel (70 %).
The determined low efficiency is caused by large quantity of heat losses particularly due to
excess air and moisture in the fuel, i.e. bagasse that should be transferred to steam. The
investigation on the steam distribution systems also shows there is significant amount of losses
due to deteriorated steam distribution line thermal insulation and steam leakages.
The study conducted on both steam generation units (boilers), thermal losses due to deteriorated
insulation of steam lines and steam leakages identified energy conservation measures of annual
saving potential of 17,807ton of bagasse which could avoid additional fuel/FO utilization and
enhance generation of electricity that significantly reduce grid electricity dependency of the
factory.
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Keywords
Cogeneration, energy audit, energy saving opportunities, energy conservation, efficiency improvement, energy conservation measures, power quality