(77a) Life Cycle Analysis of Biodiesel from an Integrated Algal Biorefinery

In this work, we conduct a cradle-to-gate life cycle analysis for the production of algal biodiesel [1]. We develop an integrated system that includes a wide range of technology alternatives in seven sections: cultivation, harvesting, lipid extraction, remnant treatment, biogas utilization, biofuel production, and bioproduct manufacturing [2-4]. This system allows the selection of a number of processes to produce biodiesel from microalgae. In addition to the generation of electricity, there are multiple coproducts that are able to be manufactured, including fertilizer, methanol, and four bioproducts. The functional unit is defined as 1kg of biodiesel produced and the environmental impact is allocated to coproducts based on economic values. We evaluate the carbon footprints of biodiesel and the bioproducts from several promising process configurations, and achieve reduction of greenhouse gas emissions by 5% to 63% compared with fossil-based counterparts.

References

[1]        J. Gong and F. You, "Value-Added Chemicals from Microalgae: Greener, More Economical, or Both?," ACS Sustainable Chemistry & Engineering, vol. 3, pp. 82-96, 2015.

[2]        J. Gong and F. Q. You, "Optimal Design and Synthesis of Algal Biorefinery Processes for Biological Carbon Sequestration and Utilization with Zero Direct Greenhouse Gas Emissions: MINLP Model and Global Optimization Algorithm," Industrial & Engineering Chemistry Research, vol. 53, pp. 1563-1579, Jan 29 2014.

[3]        J. Gong and F. Q. You, "Global Optimization for Sustainable Design and Synthesis of Algae Processing Network for CO2 Mitigation and Biofuel Production Using Life Cycle Optimization," AIChE Journal, vol. 60, pp. 3195-3210, Sep 2014.

[4]        L. B. Brentner, M. J. Eckelman, and J. B. Zimmerman, "Combinatorial Life Cycle Assessment to Inform Process Design of Industrial Production of Algal Biodiesel," Environmental Science & Technology, vol. 45, pp. 7060-7067, Aug 15 2011.