13,224 research outputs found

    Numerical and experimental investigation of static shaft Wankel expander for compressed-air energy storage

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    Compressed air energy storage (CAES) is a promising technology for storing mechanical and electrical energy using the gas power cycle. The expansion device is a critical component of the CAES that determines the overall performance of the system. Standard Wankel expander (SWE) is one of the volumetric expanders which has several advantages including low vibration, ability to produce high power output, low manufacturing cost and less moving parts. However, SWE requires valves for timing the inlet and outlet flow and a balancing system to ensure reliable operation. Static shaft Wankel expander (SSWE) is an attractive solution to enable valves’ removal and the need for balancing system. This paper presents a detailed experimental and numerical investigation of an SSWE performance at various operating pressures and temperatures for CAES application. An advanced computational fluid dynamic simulation model taking into account the dynamic motion of the SSWE and utilising real gas air properties. A compressed air test rig was constructed and instrumented with temperature, flow rate, pressure and torque sensors. Experimental testing at temperatures 20 °C to 80 °C and pressures of 1.5 bara to 3 bara was conducted and compared to the CFD simulations results. Correlations were developed for the friction power loss. Experimental results showed that the developed SSWE can produce power output of 504 W at 80 °C and 3 bara and its isentropic efficiency reached 71 % at 60 °C and 2 bara.<br/

    Graduate Catalog of Studies, 2023-2024

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    Pathways for the Valorization of Animal and Human Waste to Biofuels, Sustainable Materials, and Value-Added Chemicals

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    Human and animal waste, including waste products originating from human or animal digestive systems, such as urine, feces, and animal manure, have constituted a nuisance to the environment. Inappropriate disposal and poor sanitation of human and animal waste often cause negative impacts on human health through contamination of the terrestrial environment, soil, and water bodies. Therefore, it is necessary to convert these wastes into useful resources to mitigate their adverse environmental effect. The present study provides an overview and research progress of different thermochemical and biological conversion pathways for the transformation of human- and animal-derived waste into valuable resources. The physicochemical properties of human and animal waste are meticulously discussed, as well as nutrient recovery strategies. In addition, a bibliometric analysis is provided to identify the trends in research and knowledge gaps. The results reveal that the USA, China, and England are the dominant countries in the research areas related to resource recovery from human or animal waste. In addition, researchers from the University of Illinois, the University of California Davis, the Chinese Academy of Sciences, and Zhejiang University are front runners in research related to these areas. Future research could be extended to the development of technologies for on-site recovery of resources, exploring integrated resource recovery pathways, and exploring different safe waste processing methods

    Carbon emissions from in-situ pyrolysis of tar-rich coal based on full life cycle analysis method

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    The control of carbon emissions has already become a great social strategic problem in China which must be solved at present and in the future. It is imperative to carry out safe, efficient, and low-carbon utilizations in the coal industry under the target of achieving carbon emission peak. Tar-rich coal is abundant in western China. It is mostly combusted for power generation, which results in the wastage of valuable resources and serious environmental pollution. The in-situ pyrolysis process of tar-rich coal provides a new method for generating oil from coal. This method is to produce oil without mining coal while alleviating damage and pollution to geological formations. Compared with traditional coal mining methods, it can reduce the size of goaf section and minimize the damage to rock structure. As a new coal-to-oil route, the in-situ pyrolysis of oil-rich coal is still at an initial stage for research, for which there are still few carbon emission evaluations from the perspective of the full life cycle analysis. Based on the carbon emission accounting method widely adopted, the life cycle analysis (LCA) is employed to analyze the carbon dioxide emission in the whole process of an in-situ tar-rich coal pyrolysis project, including coal seam modification, in-situ heating, product processing, product transportation and terminal consumption. A lateral comparison of greenhouse gas inventory with indirect coal liquefaction and direct coal liquefaction is also carried out. At the same time, the greenhouse gas emission from the in-situ pyrolysis of tar-rich coal is analyzed systematically. The results show that it is necessary to adopt low-carbon energy in the development of in-situ pyrolysis of oil-rich coal. With power grid as the energy source, the LCA carbon emission of in-situ pyrolysis is about 2.234 5 t CO2 for each tonne of coal treated, while with wind power as the energy source, merely 0.608 6 t CO2. The in-situ pyrolysis of tar-rich coal has an obvious advantage in carbon emission reduction over indirect or direct coal liquefaction process. To reduce carbon emissions effectively, several mitigation measures need to be combined, including promoting energy efficiency, optimizing heat sources, and increasing the proportion of clean energy

    Energy recovery of sheep and ram wool for combustion and pyrolysis thermal processes

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    29 páginas, figuras y gráficos[ES] La problemática de residuos es uno de los principales desafíos de la sociedad actual. El sector textil contribuye notablemente de forma negativa. Este hecho es debido a que actualmente su aprovechamiento está pasando a segundo plano en detrimento de los más baratos tejidos sintéticos. Por ello, los ganaderos se centran en obtener leche o carne de sus explotaciones, mientras que la lana termina como un producto residual. Este trabajo trata los residuos procedentes de la lana de oveja y carnero. Para poder obtener un beneficio y evitar seguir contribuyendo a la generación de residuos, proponemos una recuperación energética a partir de estos desechos, contribuyendo a la economía circular a través de un proceso renovable y prometedor. El objetivo principal de este trabajo fue el de estudiar el comportamiento térmico de la lana para su aprovechamiento térmico en calderas de combustión y pirólisis. A través de una serie de análisis y tratamientos en laboratorio, obtuvimos datos específicos para oveja y carnero que derivaron en el posterior estudio termogravimétrico y cálculo de índices térmicos para cada muestra. Los resultados indicaron las buenas propiedades combustibles de las muestras analizadas, así como revelaron una mayor estabilidad térmica para la combustión de la lana de oveja y materia desprendida en el pico más representativo (31,660%/min) en relación al mismo valor del carnero (15,420 %/min). De la misma forma, para el proceso térmico de pirólisis, no existieron diferencias apreciables entre ambos tipos de lana.[EN] The waste problem is one of the main challenges of today's society. The textile sector contributes notably in a negative way. This fact is due to the fact that currently its use is passing into the background to the detriment of the cheapest synthetic fabrics. For this reason, farmers focus on obtaining milk or meat from their farms, while wool ends up as a residual product. This work deals with waste from sheep and ram wool. In order to obtain a benefit and avoid continuing to contribute to the generation of waste, we propose an energy recovery from this waste, contributing to the circular economy through a renewable and promising process. The main objective of this work was to study the thermal behaviour of wool for its thermal use in combustion and pyrolysis boilers. Through a series of laboratory analysis and treatments, we obtained specific data for sheep and ram that led to the subsequent thermogravimetric study and thermal indexes estimation. The results indicated the good combustible properties of the analysed samples, as well as revealed a greater thermal stability for the combustion of the sheep's wool and matter released in the most representative peak (31,660%/min) in relation to the same value of the ram (15,420 %/min). In the same way, for the thermal pyrolysis process, there were no appreciable differences between both types of wool

    Innovation in Energy Security and Long-Term Energy Efficiency Ⅱ

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    The sustainable development of our planet depends on the use of energy. The increasing world population inevitably causes an increase in the demand for energy, which, on the one hand, threatens us with the potential to encounter a shortage of energy supply, and, on the other hand, causes the deterioration of the environment. Therefore, our task is to reduce this demand through different innovative solutions (i.e., both technological and social). Social marketing and economic policies can also play their role by affecting the behavior of households and companies and by causing behavioral change oriented to energy stewardship, with an overall switch to renewable energy resources. This reprint provides a platform for the exchange of a wide range of ideas, which, ultimately, would facilitate driving societies toward long-term energy efficiency

    Carbon-Free Power

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    There is a new world order in electrical energy production. Solar and wind power are established as the low-cost leaders. However, these energy sources are highly variable and electrical power is needed 24/7. Alternative sources must fill the gaps, but only a few are both economical and carbon-free or -neutral. This book presents one alternative: small modular nuclear reactors (SMRs). The authors describe the technology, including its safety and economic aspects, and assess its fit with other carbon-free energy sources, storage solutions, and industrial opportunities. They also explain the challenges with SMRs, including public acceptance. The purpose of the book is to help readers consider these relatively new reactors as part of an appropriate energy mix for the future and, ultimately, to make their own judgments on the merits of the arguments for SMRs.Publishe

    Получение энергетически полезных продуктов из низкосортного торфа в смеси с отходами лесопиления методом термической конверсии

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    В результате проведения исследований при выполнении выпускной квалификационной работы выполнены описания объектов исследования, разработано две экспериментальные установки, разработаны две методики проведения исследований, выполнено более 120 натурных экспериментов, выполнен технический анализ получаемых полезных продуктов, а именно синтез-газа, углерода и жидких углеводородов. Было установлено существенное увеличение формирование горючих газовых компонент с высоким содержанием водорода, метана и оксида углерода, был увеличен объем углерода в результате термической конверсии топлив, а также был увеличен выход объема жидких углеводородов, что является существенным положительным результатом проделанной работы над исследованиями.As a result of the research during the final qualifying work, descriptions of research objects were made, two experimental installations were developed, two research methods were developed, more than 120 field experiments were performed, technical analysis of the useful products obtained, namely synthesis gas, carbon and liquid hydrocarbons, was performed. A significant increase in the formation of combustible gas components with a high content of hydrogen, methane and carbon monoxide was found, the volume of carbon was increased as a result of thermal conversion of fuels, and the output of liquid hydrocarbons was also increased, which is a significant positive result of the work done on the research

    Implementation of liquid organic hydrogen carrier in H2 society: Comprehensive feasibility study on H2 supply chain

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    School of Energy and Chemical Engineering (Chemical Engineering)The environmental issues derived from the usage of fossil fuels as the primary energy source have led to numerous academic, industrial, and political efforts to develop a new energy paradigm. Owing to the significant benefits of H2 from an environmental point of view, various types of efforts to develop the related crucial infrastructure to adopt H2 as the next alternative energy carrier or as the fuel by direct usage have been actively introduced. Meanwhile, regarding one of the important challenges, storage and transportation of H2, in the accomplishment of the new energy paradigm based on H2, conventional methods via compression, liquefaction, and the metal hydride require additional energy to maintain the state or show very low storage density due to the intrinsic weight of the medium. To overcome obstacles of conventional methods to store and transport the hydrogen, the concept of liquid organic hydrogen carrier was introduced as it can store produced H2 in relatively high-pressure conditions ??? hydrogenation ???, exist as the liquid state even at the standard state, release the stored H2 again by heat supply ??? dehydrogenation ??? and the liquid organic molecules used as the H2 carrier can be recycled in the H2 supply chain. As the detailed and preliminary feasibility study should be preceded to realize the commercialization of the newly proposed technology, the feasibility analysis model for various H2 supply chains regarding both economic and environmental perspectives is developed here to quantitatively evaluate each investigated scenario. In addition, quantified economic and environmental feasibility of the hydrogenation and dehydrogenation using several liquid organic hydrogen carriers and ammonia is evaluated and used in the developed model to reflect much detailed impact of the concept of liquid organic hydrogen carrier on the H2 supply chain. In this study, detailed process simulation of both hydrogenation and dehydrogenation processes for eight types of liquid organic hydrogen carrier candidates ??? N-ethylcarbazole, dibenzyltoluene, formic acid, methanol, naphthalene, methylcyclohexane, benzyltoluene, and benzene ??? and ammonia is conducted with the adoption of experimental reaction kinetics. The techno-economic analysis based on the quantified results for the performance of each investigated process obtained from the developed process simulation models is also performed to evaluate unit H2 supply cost for hydrogenation and dehydrogenation processes. In addition, the environmental assessment in terms of carbon footprint analysis quantifies the CO2 emissions, which were both directly emitted from the reaction and converted by a certain CO2 emission factor. For the H2 supply chain to H2 fueling stations in South Korea in this study, three types of H2 production methods of steam methane reforming, coal gasification, and water electrolysis are considered and 19 countries of Qatar, Australia, USA, Oman, Malaysia, Indonesia, and Russia as the main liquefied natural gas-abundant exporter, Australia, Russia, Indonesia, Canada, USA, South Africa, Columbia, and Republic of Mozambique as the main coal exporters, and China, USA, Germany, and Italy as main renewable energy exporters are assumed. Each investigated H2 supply chain, after the production of H2 in each exporting country, consists of procedures of H2 conditioning via compressed H2, liquefied H2, liquid organic hydrogen carriers, or ammonia, short-term storage via cavern, high-pressure tank, cryogenic tank, or oil tank, inland transportation via pipeline or truck, pre-processing to liquefied H2, liquid organic hydrogen carriers, or ammonia, and post-processing to compressed H2, liquefied H2, liquid organic hydrogen carriers, or ammonia with quantified unit H2 supply cost and unit CO2 emissions in the H2 supply chain are quantified. Based on the developed 520 H2 supply chains and feasibility study models, the effects of the H2 demand, CO2 capture rate, recycle ratio of liquid organic hydrogen carrier, and types of energy sources are investigated in economic, environmental, and comprehensive perspectives by adopting the technique for order of preference by similarity to ideal solution. For the effect of H2 demand, ammonia and methylcyclohexane, methanol and benzene, and ammonia are revealed as promising liquid organic hydrogen carrier candidates from economic, environmental, and comprehensive points of view. Regarding the effect of the CO2 capture rate, the methanol-based H2 supply chain is suggested as the most environmentally feasible under all CO2 capture rates investigated and the novelty of full adoption of ammonia in the H2 supply chain is shown again in the comprehensive point of view. The analysis of the effect of recycle ratio of liquid organic hydrogen carrier also reveals the novelty of full utilization of ammonia and selective adoption of methylcyclohexane in the H2 supply chain from both economic and environmental points of view. Similar to the effect of recycle ratio of liquid organic hydrogen carrier, full utilization of ammonia and selective adoption of methylcyclohexane show its significant novelty regardless of types of energy sources. From this dissertation, the feasibility study on the liquid organic hydrogen carrier -implemented H2 supply chain model is developed and economic and environmental promises of the concept of liquid organic hydrogen carrier are suggested.clos