2Department of Mechanical Engineering, Raghu Engineering College(A), Visakhapatnam, Andhra Pradesh, 531162, India
3Department of Mechanical Engineering, Raghu Engineering College(A), Visakhapatnam, Andhra Pradesh, 531162, India
4Department of Mechanical Engineering, Raghu Engineering College(A), Visakhapatnam, Andhra Pradesh, 531162, India
5Department of Mechanical Engineering, Raghu Engineering College(A), Visakhapatnam, Andhra Pradesh, 531162, India
Abstract
Rising concerns over petro-derived fossil fuel depletion and the release of toxic engine exhaust emissions reflect the serious impact of these issues on environmental pollution and their adverse effects on human health. These concerns have stimulated exploration of green, renewable
sources of biodiesel feedstocks. Algae biodiesel is regarded as a viable, sustainable, environmentally friendly alternative to fossil fuels. In the current study, oil extraction and biodiesel production were conducted using sea-green algae grown naturally on rocks in marine waters. Primarily, the wet sea green algae were harvested for oil extraction and converted into biodiesel. Sea-green algal oil was extracted using a chemical solvent-extraction method, yielding 24.25%. Further, a novel moringa oleifera dried leaves were used as a heterogeneous catalyst, which were
calcinated in an oven with hot air at a temperature of 300 – 600 oC. The obtained calcined Moringa oleifera was mixed and trans esterified. Thus, the biodiesel yield from sea-green algae oil was 94.99%. Furthermore, a definitive screening design was implemented in this study using MiniTab-
21 to maximize biodiesel yield. The design was attempted using a 3-factor, 2-level fractional factorial design from the design of experiments framework. From 18 no. of experimental runs, the sea green algae oil biodiesel yield achieved was 97.14 % at 59 oC reaction temperature, 9.5
wt. % catalyst concentration, and 12:1 molar ratio. The sea green algae oil biodiesel contained 72.28% saturated and 27.72% unsaturated fatty acids, as determined by gas chromatography. The key fuel properties of biodiesel from sea-green algae oil were tested and confirmed; the values
were within standard limits. Correspondingly, the green catalyst reusability, evaluated across 5 experimental trials, resulted in biodiesel yields greater than 50% compared with other reference studies. The definitive screening design analysis reported that the predicted value of R2 is 97.52
% and Adj. R2 value is 96.99 % which closely matches the experimental values. Finally, the addition of the green catalyst Moringa oleifera led to a maximum biodiesel yield. Thus, experimental and predicted outputs indicate the potential for utilizing sea green algae oil biodiesel as a renewable fuel in existing diesel engines, serving as an alternative to fossil fuels.
