Waste to bioenergy: a review on the recent conversion technologies

Abstract

Scientific studies have demonstrated that it is possible to generate a wide variety of bioenergy from biomass residues and waste, and however its cost is not competitive with petro-fuels and other renewable energy. Ongoing efforts are continued extensively to improve conversion technologies in order to reduce production costs. The present review focuses on the conversion technologies for transforming biomass residues and waste to biofuels, specifically their technological concepts, options and prospects for implementation are addressed. The emerging developments in the two primary conversion pathways, namely the thermochemical (i.e. gasification, liquefaction, and pyrolysis) and biochemical (i.e. anaerobic digestion, alcoholic fermentation and photobiological hydrogen production) conversion techniques, are evaluated. Additionally, transesterification, which appears to be the simplest and most economical route to produce biodiesel in large quantity, is discussed. Lastly, the strategies for direct conversion of biomass residues and waste to bioelectricity including the use of combustion and microbial fuel cells are reviewed.

The “INNOVARE” Project: Innovative Plants for Distributed Poly-Generation by Residual Biomass

“…Among the energy conversion processes, biomass gasification is a promising technology for energy generation. Waste material including agricultural and food processing residuals, as well as the humid fraction of municipal solid waste, are suitable for the potential use as biomass feedstock [11], for direct use of biofuels generation by thermochemical conversion [12]. Syngas, which can derive from the combined use of different biomasses, such as grapevine pruning mixed with coal [13] or woody biomass and sewage sludge [14], can be employed in micro-turbines under some conditions [15,16], but different issues have to be faced due to its low heating value and the variability on its composition.…”

CaXH 3 (X = Mn, Fe, Co) perovskite‐type hydrides for hydrogen storage applications

“…The works have been directed to produce a clean energy form based on hydrogen as an alternative to carbon‐based products and research interest has concentrated on transportation and storage methods for commercial applications . Apart from elementary water electrolysis, environmentally friendly production processes, that use also renewable energy sources, have been focus of the hydrogen production technologies . The development of new materials for absorption and storage of hydrogen has attracted a great deal of attention to reach safe and long term solutions .…”

“…Due to this increasing need for clean and economical energy sources, research in the field of energy has been concentrated on new and/or renewable energy sources in recent years. [2][3][4][5] Therefore, clean energy production, storage, and technological applications come into prominence to obtain continuous energy flow. In this point of view, hydrogen has gained popularity as abundant, efficient, and sustainable energy source in addition to environmental issues.…”

“…In this point of view, hydrogen has gained popularity as abundant, efficient, and sustainable energy source in addition to environmental issues. [3][4][5][6][7] The works have been directed to produce a clean energy form based on hydrogen as an alternative to carbon-based products 8 and research interest has concentrated on transportation and storage methods for commercial applications. 8,9 Apart from elementary water electrolysis, environmentally friendly production processes, that use also renewable energy sources, have been focus of the hydrogen production technologies.…”

“…8,9 Apart from elementary water electrolysis, environmentally friendly production processes, that use also renewable energy sources, have been focus of the hydrogen production technologies. 3,4,10 The development of new materials for absorption and storage of hydrogen has attracted a great deal of attention to reach safe and long term solutions. [11][12][13] Gas compression and liquefaction are the common traditional techniques to store hydrogen in gas and liquid form, respectively.…”