Exploiting the potential of underutilized African plants and agricultural wastes in biofuels production

This team will demonstrate that biofuels can be sustainable, by assessing the potential to convert diverse inedible biomass (e.g. underutilized plants) into biodiesel. In addition, the project will also target the production of high value biochemicals from such inedible biomass.

Summary

Despite the vast potential of non-food plant-based biofuels, there are still exceedingly large data gaps in understanding their applicability in Africa. Presently, biofuels are largely produced from food-based oils, posing an existential threat to food security (food-versus-fuel debate). The goal of this project is to use vegetable oils from selected underutilized plants for biofuel production.

We will also produce significant amount of low-cost bio-based heterogeneous catalysts using selected agricultural wastes with significant amount of alkaline and alkaline earth metal oxides. The application of these catalysts will reduce the use of conventional homogeneous catalysts which are reported to be ineffective. On the other hand, biodiesel oxidizes during long-term storage, hence doping it with antioxidants is inevitable. Instability of biodiesel is one of the outstanding barriers towards its commercialization. Natural antioxidants extracted from plants and agricultural wastes with high phenolic contents are gaining attraction by researchers in the recent years. Synthetic antioxidants have been widely used in improving stability of biodiesels but they are expensive.

Furthermore, due to poor cold-flow properties and oxidation instability of biodiesel, catalytic upgrading of fatty acid esters through ketonization and aldol condensation is an ongoing research area in the context of improving the properties to diesel-like fuels or targeting high value applications such as aviation fuel. In this project, we intend to transform selected underutilized plants and agricultural wastes in Africa into “cash crops/wastes” for the production of biodiesels, low-cost heterogeneous catalysts, natural antioxidants, and catalytic upgraded biofuels.

Proposed Experimental set-up (transesterification process, purification of biodiesel/methyl ester and stability measurements)
Typical oxidation reaction of biodiesel: Oxidation of biodiesel starts with the removal of hydrogen from a carbon atom to produce a carbon free radical. If diatomic oxygen is present, as a result the subsequent reaction to form a peroxy radical is extremely fast. The peroxy free radical is not as reactive as the carbon free radical, but is sufficiently reactive to quickly abstract hydrogen from a carbon to form another carbon radical and a hydroperoxide (ROOH). The new carbon free radical can then react with diatomic oxygen to continue the propagation cycle. This chain reaction terminates when two free radicals react with each other to yield stable products like aldehydes, shorter chain carboxylic acids, and sediments.
 
Detailed chemistry of mixed fatty acids and cetic acid during the single step transformation to alkanes and aromatics over Cu/ZrO2 in the presence of H2

Keywords: Underutilized plants, Agricultural wastes, Biodiesel, Natural antioxidants, Catalytic upgraded biofuels

Principal investigators

Thomas Kivevele

Thomas Kivevele holds a doctorate and master’s degree in Mechanical Engineering from Tshwane University of Technology, South Africa majoring in thermal energy and bioenergy, respectively. Thomas also holds a Bachelor of Science Degree in Electro-Mechanical Engineering from the University of Dar Es Salaam, Tanzania. He is a recipient of 2018 Fulbright fellowship to conduct research in biofuels at Baylor University, TX, United States. 

Thomas Kivevele has been a leader of five projects funded by The World Academy of Sciences, Tanzania Commission for Science and Technology, International Atomic Energy Agency, Erasmus+ of the European Union and the PASET Regional Scholarship and Innovation Fund. 

Thomas is currently working as a Senior Lecturer at the School of Materials, Energy, Water and Environmental Sciences (MEWES), Nelson Mandela African Institution of Science and Technology (NM-AIST), Arusha – Tanzania.

Jeremy Luterbacher

Jeremy Luterbacher received a master’s degree in Chemical Engineering from EPFL in 2007. During his master, he spent one year as a visiting scientist at the MIT working on hydrothermal biomass gasification in Pr. Jeff Tester’s lab. Jeremy then moved to Cornell University to pursue doctoral studies in Pr. Larry Walker’s lab, working on biomass pretreatment and enzymatic hydrolysis of biomass. He was awarded the Austin Hooey Graduate Research Excellence Recognition by the Cornell Department of Chemical and Biomolecular Engineering.

After receiving his PhD, Jeremy joined the University of Wisconsin-Madison as a Swiss National Science Foundation Postdoctoral Scholar. He worked there for two years on solvent-aided chemical biomass depolymerization and aqueous phase catalytic reforming under the supervision of Pr. Jim Dumesic. In 2014, Jeremy returned to EPFL as a Tenure-Track Assistant Professor and head of the Laboratory of Sustainable and Catalytic Processing.