Research Projects

The depletion of fossil fuel reserves and the growing global energy demand have led to a steep rise in crude oil prices, making conventional fuels less affordable [1]. This has driven global interest toward renewable alternatives, with biodiesel emerging as a clean, biodegradable, and eco-friendly fuel for the transportation sector. Recognizing this potential, the Indian government has set a target to blend 20% ethanol in petrol and 5% biodiesel in diesel by 2030, promoting indigenous biofuel production through various initiatives [2]. Currently, transesterification is the most widely used method for biodiesel production. However, catalyzed commercial processes face significant challenges related to catalyst recovery, downstream separation, and wastewater generation [3]. In contrast, non-catalytic subcritical fluid-based production offers a sustainable and innovative alternative. This process involves superheating alcohol beyond its boiling point under subcritical conditions and injecting it into a bubble column reactor containing triglycerides. The superheated fluid facilitates faster reaction rates, easy separation, and eliminates the need for catalysts or water treatment, thereby simplifying the process and reducing costs [4][5]. Harnessing solar energy to power this process enhances sustainability and energy efficiency. Solar-powered systems can heat the alcohol-triglyceride mixture to subcritical temperatures using solar collectors. While flat-plate collectors have been explored, parabolic dish collectors offer superior performance due to their high concentration ratios and ability to reach temperatures above 250 °C, making them ideal for subcritical biodiesel synthesis [6]. These systems focus direct solar radiation onto a central receiver, providing sufficient thermal energy for catalyst-free transesterification. The use of solar thermal energy ensures uniform heating, improves mass and heat transfer, and increases reaction rates. Additionally, the absence of catalysts allows for simple separation of the biodiesel from excess alcohol using devices such as rotary evaporators [7]. The final product can be tested for performance and emissions in internal combustion (IC) engines to validate its practical viability [8]. In summary, integrating concentrated solar thermal energy—particularly via parabolic dish collectors—into non-catalytic subcritical biodiesel production presents a novel, scalable, and environmentally sustainable solution. Utilizing waste or non-edible oils as feedstocks, this method offers a cost-effective alternative that aligns with global energy and climate goals while addressing the dual challenges of rising edible oil and fuel prices.