A Review of Thermochemical Technologies for the Conversion of Waste Biomass to Biofuel and Energy in Developing Countries

Abstract

Rising energy security concerns associated with the depleting fossil fuel reserves have triggered renewed interests in the utilisation of biomass for energy. Highly vulnerable to the energy instability, developing countries are turning to thermochemical technologies for the conversion of biomass to biofuels to displace the use of the traditional fossil fuels. A comparative analysis of the potentials of thermochemical conversion technologies of biomass to biofuels and energy in developing countries was conducted. The current status of biomass combustion, cogeneration, gasification, pyrolysis and torrefaction were assessed in different emerging economies, namely, South Africa, Ghana, Malaysia, China, India, Thailand, Tanzania, Brazil and Mauritius. Biomass combustion and cogeneration held the foothold at commercial level both in industrialised and developing countries based on technology maturity and reliability. Biomass gasification is evolving as an eminent method for the production of energy and power in various developing countries. India and China have already embarked on the commercialisation of biomass gasification projects, while other nations have enrolled on pilot-scale schemes. The effectiveness, versatility and environment-friendly aspect of biomass gasification have favoured its preferred integration in the energy system in contrast to combustion and other techniques. Biomass pyrolysis is as promising as gasification in the production of pyrolysis oil to generate transportation fuels. Presently limited at demonstration scale, pyrolysis is being extensively investigated to promote its rapid scale-up and commercial application. Pyrolysis oil represents a crucial resource for the generation of other biofuels, chemicals and power. Torrefaction is a desirable pre-treatment prior to advanced thermal treatment of biomass as it enhances the energy density of processed biomass. Still in its infancy, torrefaction is recurrently being studied to facilitate its large-scale application. The reluctance to adopt biomass thermochemical conversion technologies in developing countries is accounted by economical, technical and social issues. Thermochemical conversion of biomass to biofuel can become important Clean Development Mechanism (CDM) projects with mitigated greenhouse gas (GHG) emissions in the long run.