9,365 research outputs found

    Heat exchanger/reactors (HEX reactors): Concepts, technologies: State-of-the-art

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    Process intensification is a chemical engineering field which has truly emerged in the past few years and is currently rapidly growing. It consists in looking for safer operating conditions, lower waste in terms of costs and energy and higher productivity; and away to reach such objectives is to develop multifunctional devices such as heat exchanger/reactors for instance. This review is focused on the latter and makes a point on heat exchanger/reactors. After a brief presentation of requirements due to transposition from batch to continuous apparatuses, heat exchangers/reactors at industrial or pilot scales and their applications are described

    Dehydration of Gas Mixture Using Throttling Valve: Effect of Pressure & Effect on Moisture Content

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    Natural gas hydrate has always bring major problem to pipelines corrosion and plugging. Many technologies have been invented and applied to tackle this problem. The widely used and most feasible technologies used is absorption by using triethylene glycol (TEG). This technology has been used in industry for decades due to its promising efficiency. However, its packing column requires a large column space for maximizing the absorption amount. Besides, there are other drawbacks of using this method such as desiccant effectiveness which decreases promptly at temperatures greater than 80°F (26.67°C) and high energy consumption. Hence, the throttling technique is proposed to remove moisture content in natural gas mixture in achieving the essentials for critical offshore application, which removes water vapor in large production, small size and less weight. The advantage of the proposed system include self-induced refrigeration, small in size, low operating cost, simple mechanical design and unlikely to form hydrates. In this project, relationship between feed pressure and temperature drop in a throttling valve is studied. On top of that, the effect on different moisture content in hydrocarbon mixture with various throttling pressure is studied. Mathematical study is also developed to model and validate the temperature drop for different gas mixture under different feed pressure in a throttling valve. Calculated value is compared with experimental data to study the contributing factor of efficient water removal. Dehydration via throttling valve can be achieved by controlling the parameters: eg., increasing the feed pressure with constant temperature and increasing the feed temperature with inlet pressure kept constant. The dehydration of gas mixture by using throttling valve deemed a valuable result noting that the effectiveness of the throttling valve can go up to 87% if a proper insulation is installed

    Pretreatment Processes of Biomass for Biorefineries: Current Status and Prospects

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    Producción CientíficaThis article seeks to be a handy document for the academy and the industry to get quickly up to speed on the current status and prospects of biomass pretreatment for biorefineries. It is divided into two biomass sources: vegetal and animal. Vegetal biomass is the material produced by plants on land or in water (algae), consuming sunlight, CO2, water, and soil nutrients. This includes residues or main products from, for example, intensive grass crops, forestry, and industrial and agricultural activities. Animal biomass is the residual biomass generated from the production of food from animals (e.g., manure and whey). This review does not mean to include every technology in the area, but it does evaluate physical pretreatments, microwave-assisted extraction, and water treatments for vegetal biomass. A general review is given for animal biomass based in physical, chemical, and biological pretreatments

    Topical scientific researches into resource-saving technologies of mineral mining and processing

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    Table of contents Preface . 5 Malanchuk Z.R., Soroka V.S., Lahodniuk O.A., Marchuk M.M. Physical-mechanical and technological features of amber extraction in the Rivne-Volyn region of Ukraine . 6 Moshynskyi, V.S., Korniyenko V.Ya., Khrystyuk A.O., Solvar L.M. Research of energy effective parameters of the process of hydro mechanical extraction of amber from sandy deposits . 24 Mohamed Tafsir Diallo, Mamadou Oury Fatoumata Diallo Tidal Park – Modeling and Control Strategy . 38 Savina N.B., Malanchuk L.O., Ignatiuk I.Z., Moshchych S.Z. Institutional basis and trends of management of the use of the subsoil in Ukraine . 51 Dedelyanova Kr.Y. Column flotation machine – innovative aeration, vibra-tory – acoustic and technological researches . 60 Makarenko V.D., Manhura A.M., Lartseva I.I., Manhura S.I. Magnetic field on asphalt, resin, paraffin and salt deposits 79 Krzysztof Tomiczek The problem of beds stability in the conditions of undermining higher deposited beds in the context of selected analytical solutions . 95 Safonyk A.P., Koziar M.M., Martyniuk P.M., Fylypchuk V.L. Management of pollution - purification system for mining plants . 117 Marinela Panayotova, Vladko Panayotov Recent developments in the flotation of sulfide ores of base metals - bioflotation . 130 Remez N., Dychko A., Bronytskyi V., Kraychuk S. Simulation of shock waves from explosion of mixture explosive charges . 149 Melodi M.M. Akande V.O. Analysis of productivity and technical efficiency in granite aggregate production in selected quarries in south-western, Nigeria . 166 Doroshenko Ya.V., Karpash O.M., Rybitskyi I.V. Investigation of dispersed contaminates influence on the hydraulic energy consumption of elements of gas pipeline systems with complex geometry . 182 Skipochka S.I., Krukovskyi O.P., Krukovska V.V., Palamarchuk T.A. Features of methane emission in coal mines at high speed longwall face advance 208 Daouda Keita, Valery Pozdnyakov Statistical analysis of experimental data on the indices of operation of the loading units of the bauxite compa-ny of Guinea (CBG) . 226 Yevhenii Malanchuk, Sergiy Stets, Ruslan Zhomyruk, Andriy Stets Modeling of the process of mining of zeolite-smectite tuffs by hydro-well method . 244 Samusia V. I., Kyrychenko Y. О., Cheberiachko I. M., Trofymova, O. P. Development of experimental methods to study heterogenic flows in the context of hydraulic hoisting design . 260 Makarenko V.D., Kharchenko M.O., Manhura A.M., Petrash O.V. Magnetic treatment of production fluid with high content of asphalt-resin-paraffin deposits . 268 Kovshun N.E., Ignatiuk I.Z., Moshchych S.Z. Malanchuk L.O. Innovative model of development of fuel and energy complex of Ukraine 279 Bondarenko А.O., Ostapchuk O.V. Design and implementation of a jet pump dredge . 296 Sotskov V.O., Dereviahina N.I. Research of dependencies of stope stress-strain state change under various conditions of partial stowing of developed space . 305 Sakhno S., Liulchenko Y., Chyrva T., Pischikova O. Determination of bear-ing capacity and calculation of the gain of the damaged span of a railway overpass by the finite element method . 326 Melodi М.М., Ojulari M.K. Oluwafemi V.I. Economic and environmental impacts of artisanal gold mining on near-by community of Sauka-Kahuta, Nigeria . 340 Kruchkov A.I., Besarabets Y.J., Yevtieieva L.I. Energy saving modes of excavators type power shovel . 353 Hryhorash M.V., Kuzminskyi V.P., Ovchinnikova O.V., Kukhar V.Yu. Energy saving through quality of technical water: new types of mechanical screen filters for various links of water treatment . 369 Didenko M. The modeling of the interaction of rock mass and compliant lining while it is expanded . 394 Makarenko V.D., Liashenko A.V. Complex approach to research and selection of hydrocarbon solvents for asphaltene-resin-paraffin-hydrate deposits control . 408 Mykhailovska O.V., Zotsenko M.L. Investigation of the oscillations amplitudes bases and foundations of the forming machine . 417 Inkin O.V., Puhach A.M., Dereviahina N.I. Physical-chemical and technological parameters of improving profitability of underground coal burning . 42

    Current Status and Future Perspective of Waste Printed Circuit Boards Recycling

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    AbstractFor waste electrical and electronic equipment (WEEE), large quantities of waste printed circuit boards (PCBs) are released into environment. In light of their characteristics including complex structures, high metals content and potential hazards, waste PCBs are regarded as the most difficult parts of WEEE to be recycled. Therefore in recent ten years, the issue has attracted much attention from researchers and enterprises. This article reviews the latest processes of waste PCBs developed from laboratories to pilot engineering applications, and presents the most suitable available technology for waste PCBs, typically categorized as manually dismantling and automatic approaches in developing and developed countries, respectively. Towards achieving the better sustainability and recyclability for waste PCBs, nonmetal powder and precious metals should be developed for a deep recovery following mechanical treatment. Additionally, a significant shift is emerging from dismantling for recycling of printed wiring boards, to disassembling for remanufacturing of electronic components, which will indicate that a new paradigm of reclaiming waste PCBs is shaping

    An Overview of EGS Development and Management Suggestions

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    The world is facing the energy challenge to over-reliance to fossil-fuels, the development of renewable energy is inevitable. From a clean and economic view, enhanced geothermal system (EGS) provides an effective mean to utilize geothermal energy to generate. Different form the conventionalhydro geothermal, the host rock of EGS is Hot Dry Rock (HDR), which buries deeper with high temperature (more than 180°C). The generationof EGS is promising. The development of EGS can be combined with the tech Power to geothermal energy. Exceed power is supposed to drive fluid working in HDR layer to obtain geothermal energy for generation. The whole article can be divided into three parts. In the first art, evaluation indexes of EGS as well as pilot EGs Projects (e.g. Fenton Hill and Basel) and exiting EGS project (e.g. Paralana and Newberry) are summarized, which points a general impression on EGS site. The dominate indexes are heat flow, geothermal gradient and thermal storage. The second part is focused on the simulation methods and working fluids selection of EGS. A detailed comparison of the main simulation software (e.g. TOUGH2 and FEHM) is carried out. With the respect of working fluid selection, the comparison between water and CO2 is researched and CO2 is a preferred option for EGS development for less fluid loss and less dissolution to HDR. The art of CO2-EGS is introduced clearly in this part. The third part is about the addition consideration of EGS plant operation, it excludes auxiliary plant support and HSE management

    Examining the Relationship Between Lignocellulosic Biomass Structural Constituents and Its Flow Behavior

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    Lignocellulosic biomass material sourced from plants and herbaceous sources is a promising substrate of inexpensive, abundant, and potentially carbon-neutral energy. One of the leading limitations of using lignocellulosic biomass as a feedstock for bioenergy products is the flow issues encountered during biomass conveyance in biorefineries. In the biorefining process, the biomass feedstock undergoes flow through a variety of conveyance systems. The inherent variability of the feedstock materials, as evidenced by their complex microstructural composition and non-uniform morphology, coupled with the varying flow conditions in the conveyance systems, gives rise to flow issues such as bridging, ratholing, and clogging. These issues slow down the conveyance process, affect machine life, and potentially lead to partial or even complete shutdown of the biorefinery. Hence, we need to improve our fundamental understanding of biomass feedstock flow physics and mechanics to address the flow issues and improve biorefinery economics. This dissertation research examines the fundamental relationship between structural constituents of diverse lignocellulosic biomass materials, i.e., cellulose, hemicellulose, and lignin, their morphology, and the impact of the structural composition and morphology on their flow behavior. First, we prepared and characterized biomass feedstocks of different chemical compositions and morphologies. Then, we conducted our fundamental investigation experimentally, through physical flow characterization tests, and computationally through high-fidelity discrete element modeling. Finally, we statistically analyzed the relative influence of the properties of lignocellulosic biomass assemblies on flow behavior to determine the most critical properties and the optimum values of flow parameters. Our research provides an experimental and computational framework to generalize findings to a wider portfolio of biomass materials. It will help the bioenergy community to design more efficient biorefining machinery and equipment, reduce the risk of failure, and improve the overall commercial viability of the bioenergy industry

    GLOBALIZATION AND ECON0MIC CONVERGENCE: AN ASSESSMENT

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    This paper offers a critical survey of a strong globalization thesis that predicts a direct link from more open trade and investment regimes to faster economic growth in developing countries and income convergence across the global economy. Its examination of recent experience suggests that while in a more open and integrated world economy both the quantity and the quality of investment are influenced by external factors the forces driving capital accumulation retain strong domestic roots and remain open to the influence of various types of policy initiative.
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