A comparative investigation of biodiesel generation from fish oil and beef tallow utilizing an alkali catalyzed transesterification approach

Abstract

The combustion of fossil fuels is a significant contributor to elevated greenhouse gas levels, air pollution, and climate change. Biodiesel, a sustainable and biodegradable alternative, presents a potential remedy for these pressing environmental concerns. Nevertheless, the selection of appropriate feedstocks for biodiesel production is crucial to ensure its long-term sustainability and cost-effectiveness. This research investigated the possibility of utilizing readily available waste materials, beef tallow and fish oil, as alternative sources of biodiesel fuel through alkali-catalyzed transesterification. The transesterification process was optimized for both the beef tallow and fish oil feedstocks. The optimized conditions included a methanol to oil molar ratio of 6:1, a potassium hydroxide catalyst loading of 1% by weight, and a reaction temperature of 60°C.The characterization analysis of the produced biodiesels shows that both beef tallow and fish oil biodiesels exhibited densities (beef tallow: 885 g/mL, fish oil: 892 g/mL) and flash points (beef tallow: 170 °C, fish oil: 156 °C) within the specified ranges. However, both biodiesels exceeded the standard limit for water content (mg/kg) (beef tallow: 565, fish oil: 191, necessitating further purification before practical application. Analysis of the Fatty Acid Methyl Ester
(FAME) profile provided valuable insights. Beef tallow biodiesel exhibited a higher content of shorter chain fatty acids compared to fish oil biodiesel, potentially leading to a slightly higher yield (89.2%) and improved cetane number (60.2). This study demonstrates the promising potential of utilizing waste animal fats for biodiesel production, contributing to energy security, environmental sustainability, and waste management solutions.