Biodiesel from Microalgae Based on Co2 Released from Cement Industries (Case Study: - Dangote Cement Plant)
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Date
2016-06
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Addis Ababa University
Abstract
Fossil fuels which are recognised as common sources of energy are continuously decreasing
in quantity due to increasing demand, Moreover, the increase in atmospheric carbondioxide
from chemical industries like cement plants is resulting in global climate change. In order to
achieve environmental and economic sustainability, 3rd generation biofuel derived from
microalgae are considered to be the best alternative energy resource compared to 1st and 2nd
generation biofuels. Mixed species of microalgae was sourced locally from Kilole Lake at
Bishoftu district and found suitable feed stock to produce algal biodiesel in the laboratory.
Experiments were carried out using PVC jars of 3.5 litre capacity using 0.1 to 4%
carbondioxide concentration, air bubbling rate of 0.1 to 7.0 litre per minute and pH ranged
between 5 -7. The maximum biomass was obtained 0.44 gm/lt at pH 7, bubbling rate 3.5
lt/min and 2% carbondioxide feed. Oil was extracted from the algal biomass and analysed for
water content, acid value, and fatty acid composition and saponification value. Algal oil fatty
acid composition was very low and as a result of this no pre-treatment of algal oil was
needed. Biodiesel produced by transesterfication of algal oil performed by using sodium
methoxide as catalyst, and it was analysed for kinematic viscosity, specific gravity, acid value
and sulphated ash. The properties of biodiesel tested were within limits of ASTM standard.
Scale up of biodiesel plant in integration with the cement industry facility was studied as a
way to mitigate the carbondioxide released from the plant flue gas as well as to address the
shortage of fossil fuel in our country. Using the preliminary design of the biodiesel plant, a
production capacity of 5,860 ton/year biodiesel was obtained and it was possible to capture
22,893.3 ton per year carbondioxide released from the cement industry. The net energy ratio
of the proposed plant is 1.03; meaning 3% of energy can be produced more than required by
the process.
Key words: - Algal biomass, carbon dioxide, lipid oil, Biodiesel, Raceway pond
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Keywords
Algal biomass; carbon dioxide; lipid oil; Biodiesel; Raceway pond