Cashew nutshell liquid: A potential inedible source of biodiesel for heavy duty vehicles in sub-Saharan Africa

ABSTRACT

To maintain the global temperature, increase below 2°C, efficient bioenergy use is necessary. Many developed countries have successfully adopted biofuel into their energy mix, but sub-Sahara African (SSA), which has a comparative advantage in terms of land, labor, and climatic conditions for energy crops is trailing. Transportation in SSA is petroleum dependent and driven, with diesel fuel being the most used for heavy-duty vehicles, contributing significantly to the greenhouse gas (GHG) emissions in the region. Bioenergy has been identified as one of the energy resources that will play an essential role in reducing GHG emissions. Throughout the SSA region, different energy crops are grown and cashew nuts with shells, in which the waste are used to produce cashew nut shell liquid (CNSL), are cultivated and harvested in an area of 1,157,001–4,704,272 hectares, which is an increase of 406% from 2000 to 2019. As a result, 30,104,678 metric tons of cashew nuts with shell are produced, representing 51% of global production within the years under review, and approximately 6,020,935 metric tons of CNSL agro-industrial waste are generated. The paper discusses cashew nut post-harvest residue suitable for production of CNSL an inedible biodiesel feedstock for diesel engines. It also discusses CNSL extraction procedures, viscosity reduction methods, and fuel characteristics of various blends with additives. The study concluded that utilization of CNSL biodiesel can reduce the dependence of SSA on petroleum diesel while reducing GHG emissions.

KEYWORDS:

• Cashew nutshell liquid
• compression ignition engine
• heavy-duty vehicle
• inedible feedstock
• sustainable biodiesel

Acknowledgements

This project received the funding support from Ghana Education Trust Fund (GETFund), Reference Number: GC 147/905/01MA.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Ghana Education Trust Fund (GETFund), Reference Number: GC 147/905/01MA.

Notes on contributors

Robert K. Biscoff

Robert K. Biscoff is currently a PhD candidate in the Department of Mechanical, University of South Africa. He is also a Lecturer at Ho Technical University, Ghana. His research interests include bioenergy, alternative fuels for ICE, motor vehicle emissions and pollution control and vehicle road safety.

Christopher C. Enweremadu

Christopher C. Enweremadu is a Professor in the Department of Mechanical Engineering, University of South Africa. He has authored many articles in the field of renewable energy. His research areas include alternative fuel (biogas, biodiesel, and bioethanol) production, energy efficiency, solar energy, heat and mass transfer.