The demand for sustainable energy sources has increased owing to environmental concerns, such as climate change, rising energy demand and rapid industrialization. Biomass utilization for bioenergy and value‐added chemical production has become essential for creating a circular low‐carbon bioeconomy and sustainable waste management techniques. This review focuses on thermochemical processes and analyzes the trends of biomass utilization for energy production in the EU over the last decade. It discusses the current state‐of‐the‐art of gasification, pyrolysis, advanced combustion and liquefaction technologies, and presents the individual challenges and prospects of each process. A comprehensive overview of previous studies related to each conversion technology is provided to pave the way for future thermochemical, biochemical and integrated biomass valorization studies. Additionally, the review discusses biomass thermochemical conversion processes, which are combined with carbon capture, such as gasification, liquefaction and pyrolysis. These processes offer the potential to achieve negative net atmospheric carbon emissions, which can contribute to global warming mitigation efforts.
2,6-Dimethylnaphthalene (2,6-DMN) is a commercially important chemical for the production of polyethylenenaphthalate and polybutylene naphthalate. However, its complex synthesis procedure and high production cost significantly reduce the use of 2,6-DMN. In this study, the synthesis of 2,6-DMN was investigated with methylation of 2-methylnaphthalene (2-MN) over metal-loaded beta zeolite catalysts including beta zeolite, Cu-impregnated beta zeolite and Zr-impregnated beta zeolite. The experiments were performed in a fixed-bed reactor at atmospheric pressure under a nitrogen atmosphere. The reactor was operated at a temperature range of 400–500 °C and varying weight hourly space velocity between 1 and 3 h−1. The results demonstrated that 2,6-DMN can be synthesized by methylation of 2-MN over beta type zeolite catalysts. Besides 2,6-DMN, the product stream also contained other DMN isomers such as 2,7-DMN, 1,3-DMN, 1,2-DMN and 2,3-DMN. The activity and selectivity of beta zeolite catalyst were remarkably enhanced by Zr impregnation, whereas Cu modification of beta zeolite catalyst had an insignificant effect on its selectivity. The highest conversion of 2-MN reached 81%, the highest ratio of 2,6-DMN/2,7-DMN reached 2.6 and the highest selectivity of 2,6-DMN was found to be 20% by using Zr-modified beta zeolite catalyst.
Biomass valorisation for bioenergy is crucial for establishing a sustainable low-carbon circular bioeconomy and addressing societal and environmental challenges. As global demand for renewable energy grows, effective waste management using biomass becomes increasingly vital. However, successful implementation requires addressing specific local, scientific, and conceptual challenges, including technological intricacies, resource availability, scalability, and environmental impacts. Advancements in chemical looping gasification and chemical looping combustion are reviewed here as essential components of bioenergy with carbon capture and storage technologies. Chemical looping technologies have substantially contributed to decarbonising various industries, supported by precise trends. The review highlights the potential of chemical looping combustion and gasification in biomass utilisation for generating bioenergy and mitigating carbon emissions. Moreover, the advantages of chemical looping processes enhance their feasibility and applicability across different contexts including (1) significant increase in biomass conversion efficiency through chemical looping gasification, leading to substantial reductions in greenhouse gas emissions, (2) progress in chemical looping combustion, enhancing carbon capture and storage capabilities and contributing to a closed carbon cycle, (3) detailed insights into integrating chemical looping technologies into industrial sectors.
1 April 2019 in Sustainable Energy Technologies and Assessments