Upgrading Biogas for Small – Scale Electricity Generation From Food Waste, A Case Study of Sidist Kilo University
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Date
2018-10
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Addis Ababa University
Abstract
Now a day‟s biogas from food waste is an alternative and a viable energy sources for
domestic energy consumption. Hence, this research is concerned with biogas upgrading for
electricity generation. To do this 115kg of food waste collected from student cafeterias in
Addis Ababa Sidist Kilo University used to produce 10.35m
3
biogas per day using
3
10m
digester (fiberglass roto tanker). According to the data collected from the kitchen,
41,975kg food waste is available to produce 3,777.75m
3
Biogas per year.
Due to the degree of purification and economical aspects, chemical absorption process
specifically using Ca(OH)2 solution has been selected to remove CO2 from biogas. In
addition, biogas cleaning is also done using silica gel and Activated carbon in order to
remove H2O vapor and H2S respectively. After purification, the result found from the
experiment will validate by crosschecking it with Matlab result and result found from
literature.
Compressing biomethane minimize storage space, concentrates its energy content, and
increases pressure to the required level through overcoming resistance to gas flow. From the
result, the compressor designed to compress 6.73m
3
biomethane in to 2.5m
3
for this system
the pressure increased from 1.106bar to 4bar.
As the research shows based on the investment cost, availability, and simplicity during
modification, gasoline generator became suitable to be used and generate 54.9kW electric
power per day for 9 hour using 6.1kW rated power generator.
The research indicates, economical as well as environmental benefits of biogas upgrading
technology in which the campus gained through producing 2,455.54m
3
biomethane per year.
This is equivalent with 17barrel of gasoline fuel. Moreover, it implies the potential of
generating 20.04MW of electricity per year from the campus food waste.
From economical perspective, it was possible to see that the Biogas Upgrading for
electricity is financially as well as economically feasible as the NPV is positive and benefit
cost ratio is greater than one. As financial analysis indicates, biomethane production will
save 77,945Birr annually that can be expended for Gasoline fuel.
Description
Keywords
Upgrading, food waste, biomethane, gasoline, modification