• Energy Research
• other engineering and technologies close
• 12. Responsible consumption close
• AT close
• TH close

Abstract Socio-technical transformations towards low-carbon energy systems are on the way in developed countries. Conversely, developing countries tend to be locked in fossil fuels and foster coal-based energy structures, emphasizing reliable and cost-effective energy provision and sidelining environmental concerns. In this study, we identified and analysed the predominant factors related to coal-based power generation in Bangladesh. We applied a mixed-method approach, initially conducting a systematic literature review and, subsequently, semi-structured expert interviews to identify and validate relevant factors. We then assessed their relative importance using an Analytical Hierarchy Process based on expert judgments. The results of this assessment reveal that socio-economic aspects and environmental issues scored highest, while technological aspects and sector regulations were considered to be less relevant for large-scale coal power implementation. We conclude that future energy policies created in Bangladesh will need to use appropriate legal instruments and address issues such as human displacement and resettlement, low levels of public acceptance, health hazards and environmental pollution. Participative policy frameworks should be deployed in coal plant projects, and active monitoring systems are necessary to reduce the negative consequences associated with increased electrification and energy consumption. To address foreseeable structural challenges, it furthermore will be crucial to explore sustainable alternatives.

SummaryEnvironmentally extended multiregional input‐output (EE MRIO) tables have emerged as a key framework to provide a comprehensive description of the global economy and analyze its effects on the environment. Of the available EE MRIO databases, EXIOBASE stands out as a database compatible with the System of Environmental‐Economic Accounting (SEEA) with a high sectorial detail matched with multiple social and environmental satellite accounts. In this paper, we present the latest developments realized with EXIOBASE 3—a time series of EE MRIO tables ranging from 1995 to 2011 for 44 countries (28 EU member plus 16 major economies) and five rest of the world regions. EXIOBASE 3 builds upon the previous versions of EXIOBASE by using rectangular supply‐use tables (SUTs) in a 163 industry by 200 products classification as the main building blocks. In order to capture structural changes, economic developments, as reported by national statistical agencies, were imposed on the available, disaggregated SUTs from EXIOBASE 2. These initial estimates were further refined by incorporating detailed data on energy, agricultural production, resource extraction, and bilateral trade. EXIOBASE 3 inherits the high level of environmental stressor detail from its precursor, with further improvement in the level of detail for resource extraction. To account for the expansion of the European Union (EU), EXIOBASE 3 was developed with the full EU28 country set (including the new member state Croatia). EXIOBASE 3 provides a unique tool for analyzing the dynamics of environmental pressures of economic activities over time.

AbstractChemical looping combustion is a highly efficient CO2 separation technology without direct contact between combustion air and fuel. A metal oxide is used as an oxygen carrier in dual fluidized beds to generate clean CO2. The use of biomass is the focus of current research because of the possibility of negative CO2 emissions and the utilization of biogenic carbon. The most commonly proposed OC are natural ores and residues, but complete combustion has not yet been achieved. In this work, the direct utilization of CLC exhaust gas for methane synthesis as an alternative route was investigated, where the gas components CO, CH4 and H2 are not disadvantageous but benefit the reactions in a methanation step. The whole process chain, the coupling of an 80 kWth pilot plant with gas cleaning and a 10 kW fluidized bed methanation unit were for this purpose established. As OC, ilmenite enhanced with limestone was used, combusting bark pellets in autothermal operation at over 1000 °C reaching high combustion efficiencies of up to 91.7%. The fuel reactor exhaust gas was mixed with hydrogen in the methanation reactor at 360 °C and converted with a methane yield of up to 97.3%. The study showed especially high carbon utilization efficiencies of 97% compared to competitor technologies. Based on the experimental results, a scale-up concept study showed the high potential of the combination of the technologies concerning the total efficiency and the adaptability to grid injection. Graphical Abstract

La primera biorrefinación con lignina del álamo nórdico para producir fibras de celulosa podría desplazar la producción de algodón en tierras agrícolas Al cruzar Populus trichocarpa 3 P. trichocarpa de una población distante, se obtuvieron álamos híbridos que pueden crecer rápidamente en tierras marginales en climas del norte. Estos híbridos pueden transformarse mediante fraccionamiento catalítico reductor para producir una fibra textil deslignificada que puede ser un sustituto del algodón, así como un biocombustible alimentado con lignina en el rango de gasolina-aviación-diesel. La sostenibilidad de esta cadena de valor fue evaluada por LCA y mostró beneficios sustanciales en términos de uso de agua en comparación con la producción de algodón. Le bioraffinage en lignine du peuplier nordique pour produire des fibres de cellulose pourrait déplacer la production de coton sur les terres agricoles En croisant Populus trichocarpa 3 P. trichocarpa d'une population éloignée, des peupliers hybrides ont été obtenus qui peuvent croître rapidement sur des terres marginales dans les climats nordiques. Ces hybrides peuvent être transformés par fractionnement catalytique réducteur pour donner une fibre textile délignifiée qui peut remplacer le coton ainsi qu'un biocarburant ligninérisé dans la gamme essence-aviation-diesel. La durabilité de cette chaîne de valeur a été évaluée par LCA et a montré des avantages substantiels en termes d'utilisation de l'eau par rapport à la production de coton. Lignin-first biorefining of Nordic poplar to produce cellulose fibers could displace cotton production on agricultural lands By crossing Populus trichocarpa 3 P. trichocarpa from a distant population, hybrid poplar trees were obtained that can grow rapidly on marginal lands in northern climates.These hybrids can be transformed by reductive catalytic fractionation to yield a delignified textile fiber that can be a substitute for cotton as well as a ligninderived biofuel in the gasoline-aviation-diesel range.The sustainability of this value chain was evaluated by LCA and showed substantial benefits in terms of water use compared with cotton production. يمكن للتكرير الحيوي الأول لليجنين للحور الشمالي لإنتاج ألياف السليلوز أن يحل محل إنتاج القطن في الأراضي الزراعية من خلال عبور Populus trichocarpa 3 P. trichocarpa من مجموعة سكانية بعيدة، تم الحصول على أشجار الحور الهجينة التي يمكن أن تنمو بسرعة على الأراضي الهامشية في المناخات الشمالية. يمكن تحويل هذه الهجينة عن طريق التجزئة التحفيزية المختزلة لإنتاج ألياف نسيج منزوعة الكرامة يمكن أن تكون بديلاً عن القطن بالإضافة إلى وقود حيوي خفيف في نطاق البنزين والطيران والديزل. تم تقييم استدامة سلسلة القيمة هذه من قبل LCA وأظهرت فوائد كبيرة من حيث استخدام المياه مقارنة بإنتاج القطن.

Abstract Heat exchanger is a basic component used in thermal processes such as industrial fluid heating, household appliances, waste heat recovery units (WHRU), etc. Presently, the spiral fin-and-tube heat exchanger is used as a favored type of heat exchanger for the waste heat recovery unit system, i.e., the economizer heat exchanger. The study investigates the effect of fin pitches on the air-side performance of serrated welded spiral fin-and-tube heat exchangers having Z-shape flow arrangement and the number of tube rows of 2 in range of high Reynolds numbers (4000–15,000). The test samples are made from steel (iron) with different fin pitches of 3.6, 4.2, and 6.2 mm. The experimental results reveal that the fin pitch has a significant effect on the air-side performance. It is confirmed that the fin pitch of 3.6–6.2 mm has the same trend in heat transfer coefficient at the tested condition. For f-friction factor, a detectable rise of the friction factor is found when the fin pitches increase to 6.2 mm. Moreover, the air-side performance correlations of serrated welded spiral finned tube heat exchangers are proposed for practical industrial applications. The proposed air-side performance correlation describes 100% for j-Colburn factor and f-friction factor within 10%.

Abstract In this paper, a process for the fermentative production of hydrogen is analysed with respect to its exergy efficiency. Parametric studies show the influence of used feedstock, applied process parameters as well as process and heat integration measures on exergy efficiency. It is shown that heat integration and recirculation of fermentor effluents reduce process irreversibilites and the amount of exergy leaving the process in waste streams. Nevertheless, depending on the used feedstock, a large amount of exergy leaves the process via by-products. Internal use of by-products and waste materials for providing process heat could increase chemical exergy efficiency up to 74%.

AbstractAn oleaginous yeast Rhodotorula paludigena CM33 was pyrolyzed for the first time to produce bio-oil and biochar applying a bench-scale reactor. The strain possessed a high lipid content with the main fatty acids similar to vegetable oils. Prior to pyrolysis, the yeast was dehydrated using a spray dryer. Pyrolysis temperatures in the range of 400–600 °C were explored in order to obtain the optimal condition for bio-oil and biochar production. The result showed that a maximum bio-oil yield of 60% was achieved at 550 °C. Simulated distillation gas chromatography showed that the bio-oil contained 2.6% heavy naphtha, 20.7% kerosene, 24.3% biodiesel, and 52.4% fuel oil. Moreover, a short path distillation technique was attempted in order to further purify the bio-oil. The biochar was also characterized for its properties. The consequence of this work could pave a way for the sustainable production of solid and liquid biofuel products from the oleaginous yeast.