Techno-Environmental Assessment of Biodiesel Production from Acid Oil via One-Step and Two-Step Esterification

Area of Science:

• Chemical Engineering
• Environmental Science
• Biotechnology

Background:

• Biodiesel production from acid oil is a sustainable alternative to fossil fuels.
• Acid oil is derived from crude glycerol purification, a byproduct of biodiesel production.
• Techno-environmental assessments are crucial for optimizing biodiesel production processes.

Purpose of the Study:

• To evaluate and compare the techno-environmental impacts of one-step acid catalysis and two-step enzyme/acid catalysis for biodiesel production from acid oil.
• To optimize the conversion of acid oil to biodiesel using both methods.
• To analyze the influence of different energy sources and glycerol purification on the environmental footprint.

Main Methods:

• Optimized reaction conditions for one-step esterification using sulfuric acid.
• Developed and optimized a two-step esterification process involving immobilized lipase and sulfuric acid.
• Conducted a techno-environmental assessment comparing the environmental impacts of both processes, considering factors like energy consumption, chemical usage, wastewater generation, and specific environmental indicators.

Main Results:

• The two-step process (SC-2) demonstrated technical feasibility with lower energy consumption, reduced chemical use, and less wastewater compared to the one-step process (SC-1).
• However, SC-2 exhibited higher impacts on terrestrial ecotoxicity, human noncarcinogenic toxicity, global warming potential, and land use, primarily due to enzyme preparation.
• The study identified glycerol purification as a key factor in minimizing environmental effects and enhancing sustainability.

Conclusions:

• While the two-step enzyme-acid catalyzed process is technically advantageous, the one-step acid catalyzed process is more environmentally friendly in terms of global warming and land use.
• Biodiesel production facilities should prioritize crude glycerol purification to mitigate environmental impacts.
• Further research and process optimization are needed to enhance the overall sustainability of enzyme-catalyzed biodiesel production.