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Carbon emissions from the aviation sector are expected to double during the coming three decades as the sector expands rapidly. Besides, the fluctuation of conventional fuel prices continues to obstruct the establishment of stable commercial strategies for the airlines. Meanwhile, Jet Biofuel (JBF) has been identified as a reliable alternative to conventional Jet-A fuel. Amongst the tested promising feedstocks for JBF production, Jatropha oil has gained growing attention and is believed to play a key role in the JBF industry. Though, no in-depth reviews on Jatropha JBF are found in literature, it is believed that there is a need to evaluate Jatropha as feedstock for JBF production after over 10 years of intensive research. Therefore, this article presents a comprehensive state-of-the-art review of Jatropha JBF production. The article offers a thorough review of the hydroprocessing of Jatropha by investigating its optimum operating conditions, recent catalyst application developments, the feasibility of JBF, its performance and environmental impact. This study concludes that Jatropha JBF production by hydroprocessing can achieve up to a 75% reduction in greenhouse gas emissions relative to Jet-A. While Jatropha JBF can be produced with a levelised cost as low as $0.6/kg. The main challenges facing Jatropha JBF industry has been identified to be the availability of feedstock and achieving a competitively priced JBF. As such, alternative routes to utilise the remaining parts of the Jatropha fruit into JBF production are proposed to reduce the land footprint, enhance JBF yield and minimise its selling price. The proposed pathways are expected to achieve a significant fuel yield increment of 24–89% as compared to utilising Jatropha oil alone, which remain to be evaluated in terms of technical and economic aspects. Image 1 • JBF production from Jatropha , its feasibility, performance and LCA are investigated. • Jatropha JBF production cost varies ($ 0.6–1.6/kg) based on process specifications. • Jatropha JBF can achieve up to 75% reduction in GHG emissions relative to Jet-A. • Pathways for Jatropha whole-fruit utilisation in JBF production are proposed. • Fuel yield increment of 24–89% can be achieved via the different proposed pathways. [ABSTRACT FROM AUTHOR]

The efficient and sustainable disposal or value addition of waste plastic has of major importance. Recent studies on the char produced via pyrolysis have demonstrated that it is a valuable additive with multiple applications ranging from soil and water amendment, improving agricultural yield, supercapacitors, fuel cells, and in support/catalysts, sustainable chemistry, and carbon sequestration. Thus, it is essential to ensure the quality and efficacy of biochar produced from any combination of feedstock and process to ensure maximum benefits. However, very few studies have focussed on techniques or process parameters to optimize biochar yield. This study aims to review pyrolysis techniques, reactor types, and pyrolysis parameters to identify the process parameters that could enhance the generation of biochar from co-pyrolysis of plastic and biomass feedstock. This review discusses biochar production techniques, the mechanism of pyrolysis technology, pyrolysis types, and the reactor types. This is followed by a review of the factors that can be used to optimize biochar production. Accordingly, the review identified temperature, heating rate, reactor bed height and type, residence time, pressure, feedstock type and blending ratio of feedstock as the determinants that had the highest influence on the yield, stability, and carbon content of biochar. Most importantly, the technology readiness level (TRL) of biomass pyrolysis, plastic pyrolysis and co-pyrolysis of biomass and plastic is discussed. The review necessitates further studies on these parameters to ascertain the accuracy of optimization that can be achieved by configuring pyrolysis processes to biochar production. • Co-pyrolysis of plastic, biomass and their blends are reviewed. • Pyrolysis type, mechanisms, and reactor types are critically reviewed. • Process parameters for optimum biochar yield production is discussed. • Technical maturity of the pyrolysis process, challenges, and research gaps are discussed. [ABSTRACT FROM AUTHOR]

The growing anthropogenic greenhouse gas (GHG) emissions combined with the rise of the demand on energy resources has expedited research into sustainable alternatives to fossil fuel. In this context, biomass has increased in popularity and acquired a significant share of the global energy mix in a relatively short time. However, several biomass resources have triggered wide criticism for compromising food resources, agricultural lands and fresh water to produce energy crops. Therefore, a second generation of non-edible biomass such as Jatropha curcas has become a major biofuel feedstock for several countries. Not only can its oil be converted into liquid fuels, but also the Jatropha fruit residues have high calorific value and are processed into several forms of energy. Several studies have investigated the different processing technologies to produce energy and food-related products, although no conclusions have been made on the most sustainable pathway for Jatropha utilisation considering its interlinkages to the energy, water and food resources, whilst considering its possible contributions to mitigating carbon emissions and the development of circular economies. As such, this study investigates 11 processing pathways for the major three components of Jatropha fruit from cradle to gate via a combination of three key tools including Energy-Water-Food (EWF) Nexus, Global Warming Potential (GWP) and Return on Investment (ROI). Aspen Plus software is used to simulate the production processes including transesterification, hydrotreatment, hydrocracking, gasification, pyrolysis, hydrothermal liquefaction, anaerobic digestion, saccharification and fermentation, incineration and detoxification. In addition, a mathematical model is developed to run a five-objective optimisation study using MATLAB. The model identifies an opportunity to process the Jatropha oil by transesterification (49%), hydrotreatment (28%) and hydrocracking (23%). while it is suggested that the seedcake is best utilised directly as fertilisers (35%) and processed for energy production by pyrolysis (30%) and anaerobic digestion (17%). Nevertheless, the shells of Jatropha are best utilised via SSF (32%), pyrolysis (28%), anaerobic digestion (22%) and incineration (11%). • 11 potential processing pathways of Jatropha whole-fruit are modelled in Aspen Plus. • EWF Nexus, GWP and ROI tools are used to assess the sustainability of all pathways. • Multi-objective optimisation to identify optimal pathway is developed using MATLAB. • Optimal solution maximised the net energy to 11.6 GJ per tonne of Jatropha fruit. • WF and GWP are minimised, while land footprint is compensated via food (eq) production. [ABSTRACT FROM AUTHOR]

Utilization of solar energy for multiple applications is an integral part of sustainable development primarily due to its abundance and potential to offset fossil fuel consumption. The booming field of solar energy enables the solar energy utilization, and open new opportunities within commercial and research development programs. Emphasis has been given to the new development of novel technologies that are more efficient for capturing, storing and utilizing solar energy that can store thermal energy at high temperature and across a wide temperature range. Also, the coupling of Concentrated Solar Power (CSP) and storage systems presents a significant potential to improve the capture, utilization and storage of solar energy which enhances the reliability of alternative energy options and diversifying away from fossil fuels to mitigate environmental impacts while ensuring the continuous provision of power to meet the growing demand. This paper gives an insight into the recent progress (within the last few years) in the research and development of integrated solar energy systems and their potential to improve the efficiency of integrated solar systems through the utilization of nanotechnologies. This review provides an update on integrated solar energy systems for scientists, students and industrial organizations working in the field. [ABSTRACT FROM AUTHOR]

Sustainable energy resources are a solution to the increasing energy demand caused by the accelerating population growth and the national development in the emerging countries. Biomass wastes, such as municipal solid wastes, sewage sludge, and agriculture wastes have potential to be converted into energy via thermochemical processing methods - pyrolysis and gasification. These waste treatment methods are environmentally friendly compared to direct burning and other advantages include: a reduced carbon footprint, waste emission reduction, abundant availability, and comparable energy efficiencies. The types and quantity of value-added products depend on process types and operating parameters - temperatures, catalyst, particle size and waste type. This review focuses on the production of gaseous fuel, especially syngas, from the co-conversion of biomass with other waste using the co-gasification and co-pyrolysis processes. This review critically discusses experimental and modelling studies and the key parameters - synergistic effects, reactor types, catalyst types, blending ratio, pre-treatments processes, performance efficiencies, and gasifying agents. Results reflect that mixing coal with biomass significantly reduces SO 2 , NOxs, and tar yields while increasing gas yields. The co-conversion of biomass and plastics enhances gas yields; steam with oxygen is found the best gasifying agent; while acid pretreatment and catalysts improves gas yields and reduces tar content. The review proposes future research to improve efficiencies and gas yields, thereby providing cleaner and sustainable energy for future generations, while maintaining an effective sustainable waste management scenario. Future work should study techno-economic feasibility, and environmental sustainability (using life cycle assessments) for large scale adoption of energy technologies. • A critical review of various feedstock blends for co-gasification and co-pyrolysis. • Co-conversion modelling, experimental and techno-economic studies are reviewed. • Analysis of the impact of blending ratio, catalysts, and pre-treatment on gas yield. • Effect of blend of plastic with biomass on efficient utilization. • Highlights for the challenges, future prospects and policy implications for technology upscaling. [ABSTRACT FROM AUTHOR]

Gasification has emerged as a prominent technique to convert biomass, coal, plastic, and municipals wastes sludge (generated from agriculture, industrial, and domestics, urban centers) into energy in the form of gaseous products. However, co-gasification of these materials has many advantages, such as desired product yield and uninterrupted feedstock supply as well as the sustainable utilization and disposal of these wastes. Numerous reviews have been documented based on the gasification of individual materials of biomass and coal, nevertheless, very few reviews have been reported on the process of co-gasification. In co-gasification, the effect of parameters becomes very important when dealing with the co-gasification of different mixed materials. The objective of this review to study the effect of temperature, blending ratio, and equivalence ratio (ER) on catalytic co-gasification of biomass-coal, biomass-plastic, biomass-sewage sludge, and mixed plastic blends. In addition, the effects of these parameters on gaseous products, heating values, tar formation, and gasification performance have been analyzed. It is also important to specify the ranges of parameters for the feed combinations in catalytic co-gasification that will provide a guideline for researchers and commercial enterprises to investigate co-gasification. For temperature from 650 to 750 °C found good for hydrogen rich syngas production. Whereas, the ratio of biomass 50% or above and ER of 0.20 and 0.25 were found good for higher hydrogen and lower CO 2 and tar production. Moreover, the current issues are related to technology, operational problems, policy requirements and route map for commercial success of co-gasification technology have been highlighted. Image 1 • Impact of temperature, blending ratio, and EQ ratio in co-gasification are reviewed. • Temperature (650–750 °C) is found good for higher H 2 production in co-gasification. • EQ ratio range (0.2–0.25) for gas composition and (0.3) for heating values and CCE. • Biomass content above 50% in blend found effective for gas composition. • The research gaps and technical issues highlighted for commercialization. [ABSTRACT FROM AUTHOR]