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2015

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Articles 481 - 488 of 488

Full-Text Articles in Chemical Engineering

Additives For Heat Transfer Enhancement In High Temperature Thermal Energy Storage Media: Selection And Characterization, Philip D. Myers Jr. Jan 2015

Additives For Heat Transfer Enhancement In High Temperature Thermal Energy Storage Media: Selection And Characterization, Philip D. Myers Jr.

USF Tampa Graduate Theses and Dissertations

Inorganic salts are very promising as high-temperature heat transfer fluids and thermal storage media in solar thermal power production. The dual-tank molten salt storage system, for example, has been demonstrated to be effective for continuous operation in solar power tower plants. In this particular storage regime, however, much of the thermal storage potential of the salts is ignored. Most inorganic salts are characterized by high heats of fusion, so their use as phase-change materials (PCMs) allows for substantially higher energy storage density than their use as sensible heat storage alone. For instance, use of molten sodium-potassium eutectic salt over a …

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Metallic Encapsulation For High Temperature (>500 °C) Thermal Energy Storage Applications, Abhinav Bhardwaj Jan 2015

Metallic Encapsulation For High Temperature (>500 °C) Thermal Energy Storage Applications, Abhinav Bhardwaj

USF Tampa Graduate Theses and Dissertations

Deployment of high temperature (>500 °C) thermal energy storage in solar power plants will make solar power more cost competitive and pave the way towards a sustainable future. In this research, a unique metallic encapsulation has been presented for thermal energy storage at high temperatures, capable of operation in aerobic conditions. This goal was achieved by employing low cost materials like carbon steel. The research work presents the unique encapsulation procedure adopted, as well as various coatings evaluated and optimized for corrosion protection. Experimental testing favored the use of 150 μm of nickel on carbon steel for corrosion protection …

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Silicone Elastomer-Based Combinatorial Biomaterial Gradients For High Throughput Screening Of Cell-Substrate Interactions, Greeshma Mohan Jan 2015

Silicone Elastomer-Based Combinatorial Biomaterial Gradients For High Throughput Screening Of Cell-Substrate Interactions, Greeshma Mohan

USF Tampa Graduate Theses and Dissertations

Biomaterials have evolved over the years from the passive role of mere biocompatibility to an increasingly active role of presenting instructive cues to elicit precise responses at the molecular and cellular levels. Various characteristics common to synthetic biomaterials in vitro and extracellular matrices in vivo, such as immobilized functional or peptide groups, mechanical stiffness, bulk physical properties and topographical features, are key players that regulate cell response. The dynamics in the cell microenvironment and at the cell adhesive interface trigger a web of cell-material and cell-cell information exchanges that have a profound impact in directing the ultimate cell fate …

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Influence Of Support Type And Metal Loading In Methane Decomposition Over Iron Catalyst For Hydrogen Production, Ahmed A. Ibrahim, Ahmed S. Al-Fatesh, Wasim Ullah Khan, Moustafa A. Soliman, Raja L. Al-Otaibi, Anis H. Fakeeha Jan 2015

Influence Of Support Type And Metal Loading In Methane Decomposition Over Iron Catalyst For Hydrogen Production, Ahmed A. Ibrahim, Ahmed S. Al-Fatesh, Wasim Ullah Khan, Moustafa A. Soliman, Raja L. Al-Otaibi, Anis H. Fakeeha

Chemical Engineering

Natural gas resources, stimulate the method of catalytic methane decomposition. Hydrogen is a superb energy carrier and integral component of the present energy systems, while carbon nanotubes exhibit remarkable chemical and physical properties. The reaction was run at 700 °C in a fixed bed reactor. Catalyst calcination and reduction were done at 500 °C. MgO, TiO2 and Al2O3 supported catalysts were prepared using a co-precipitation method. Catalysts of different iron loadings were characterized with BET, TGA, XRD, H2-TPR and TEM. The catalyst characterization revealed the formation of multi-walled nanotubes. Alternatively, time on stream tests of supported catalyst at 700 °C …

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Energy Intensity And Environmental Impact Metrics Of The Back-End Separation Of Ethylene Plant By Thermodynamic Analysis, Mahdi H. Alhajji, Yaşar Demirel Jan 2015

Energy Intensity And Environmental Impact Metrics Of The Back-End Separation Of Ethylene Plant By Thermodynamic Analysis, Mahdi H. Alhajji, Yaşar Demirel

Department of Chemical and Biomolecular Engineering: Faculty Publications

This study presents metrics of energy intensity and environmental impact of the back-end separation of ethylene plant consisting three interacting distillation columns by thermodynamic analysis. The objective is to explore the scope of reducing the energy for utilities and CO2 emissions. Thermodynamic analysis is carried out using the column targeting tool (CTT) to address the sustainability metrics of ‘Energy Intensity.’ CTT is based on the ‘Practical Near-Minimum Thermodynamic Condition’ representing a close to practical reversible column operation. Environmental impact metrics are estimated from the carbon tracking options. The carbon tracking are estimated by the CO2 emission data source …

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Chemical Storage Of Wind Energy By Renewable Methanol Production: Feasibility Analysis Using A Multi-Criteria Decision Matrix, Michael J. Matzen, Mahdi H. Alhajji, Yaşar Demirel Jan 2015

Chemical Storage Of Wind Energy By Renewable Methanol Production: Feasibility Analysis Using A Multi-Criteria Decision Matrix, Michael J. Matzen, Mahdi H. Alhajji, Yaşar Demirel

Department of Chemical and Biomolecular Engineering: Faculty Publications

This study is for the technoeconomic analysis of an integral facility consisting of wind energy-based electrolytic hydrogen production, bioethanol-based carbon dioxide capture and compression, and direct methanol synthesis. ASPEN Plus was used to simulate the facility producing 97.01 mt (metric tons) methanol/day using 138.37 mt CO2/day and 18.56 mt H2/day. A discounted cash flow diagram for the integral facility is used for the economic analysis at various hydrogen production costs and methanol selling prices. The feasibility analysis is based on a multi-criteria decision matrix consisting of economic and sustainability indicators comparing renewable and non-renewable methanol productions. …

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Technoeconomics And Sustainability Of Renewable Methanol And Ammonia Productions Using Wind Power-Based Hydrogen, Michael J. Matzen, Mahdi H. Alhajji, Yaşar Demirel Jan 2015

Technoeconomics And Sustainability Of Renewable Methanol And Ammonia Productions Using Wind Power-Based Hydrogen, Michael J. Matzen, Mahdi H. Alhajji, Yaşar Demirel

Yaşar Demirel Publications

This study analyzes and compares the economics and sustainability aspects of two hydrogenation processes for producing renewable methanol and ammonia by using wind-power based electrolytic hydrogen. Carbon dioxide from an ethanol plant is used for producing methanol, while the nitrogen is supplied by an Air Separation Unit (ASU) for producing ammonia. The capacities are 99.96 mt/day methanol and 1202.55 mt/day anhydrous ammonia. The methanol plant requires 138.37 mt CO2/day and 19.08 mt H2/day. The ammonia is synthesized by using 217.72 mt H2/day and 1009.15 mt N2/day. The production costs and the carbon …

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Thermo-Catalytic Methane Decomposition: A Review Of State Of The Art Of Catalysts, Ahmed A. Ibrahim, Ahmed S. Al-Fatesh, Wasim Ullah Khan, Moustafa A. Soliman, Raja L. Al-Otaibi, Anis H. Fakeeha Jan 2015

Thermo-Catalytic Methane Decomposition: A Review Of State Of The Art Of Catalysts, Ahmed A. Ibrahim, Ahmed S. Al-Fatesh, Wasim Ullah Khan, Moustafa A. Soliman, Raja L. Al-Otaibi, Anis H. Fakeeha

Chemical Engineering

The catalytic methane decomposition to produce carbon oxides–free hydrogen and carbon nanomaterial is a promising method feasible for larger production at a moderate cheap price. The produced hydrogen is refined and can be employed straight in fuel cell and in petrochemical industries to produce ammonia and methanol. Auto-thermal reforming of natural gas, partial oxidation, steam reforming are the conventional techniques for hydrogen production in industry, though these processes incur excessive costs for the purification of hydrogen from producing carbon oxides. Current research work on thermo-catalytic methane decomposition has concentrated on promoting the catalytic activity and stability for simultaneous production of …

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