Engineering Commons^™

Hydrodynamics Of Pilot-Scale Bubble Columns: Effect Of Internals, Ahmed A. Youssef, Mohamed E. Hamed, Joshua T. Grimes, Muthanna H. Al-Dahhan, Milorad P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Gas Holdup and Bubble Characteristics Are Key Parameters that Affect the Performance of Bubble Columns. an Experimental Study of the Effect of Heat Exchanging Internals on the Gas Holdup, Bubble Dynamics, and their Radial Profiles is Performed. an Air-Water System is Used in a Plexiglas Column 45 Cm (18 In.) in Diameter. Internals Configurations Mimicking Those Typical for the Liquid-Phase Methanol Synthesis and Fischer-Tropsch Process and Covering 5% and 25%, Respectively, of the Total Cross-Sectional Area of the Column, Are Investigated. High Superficial Gas Velocities that Fall within the Churn Turbulent Flow Regime, Which Are of Interest for Most …

Studies On Drying Of Sorghum Seeds In A Fluidized Bed Dryer, K. Sandeepa, V.V. Basava Rao, S. Ram Mohan Rao

The 14th International Conference on Fluidization – From Fundamentals to Products

No abstract provided.

Fluidization Regimes Characterized Using A Fast X-Ray Tomography Setup, Jean Saayman, J. Ruud Van Ommen, Rob F. Mudde, Evert C. Wagner, Willie Nicol

The 14th International Conference on Fluidization – From Fundamentals to Products

No abstract provided.

Hitran Matrix Elements As A Fluidization Promoter In Slugging Columns, Suren Sookai, Avinash Harilal

The 14th International Conference on Fluidization – From Fundamentals to Products

No abstract provided.

Green Diesel Production Via Catalytic Hydrogenation/Decarboxylation Of Triglycerides And Fatty Acids Of Vegetable Oil And Brown Grease, Elvan Sari

Wayne State University Dissertations

Increase in the petroleum prices, projected increases in the world’s energy demand and environmental awareness have shifted the research interest to the alternative fuel technologies. In particular, green diesel, vegetable oil/animal fat/waste oil and grease derived hydrocarbons in diesel boiling range, has become an attractive alternative to biodiesel— a mixture of fatty acid methyl esters, particularly due to its superior fuel properties that are similar to petroleum diesel. Hence, green diesel can be used as a drop-in fuel in the current diesel engines. The current technology for production of green diesel– hydrodeoxygenation of triglycerides and fatty acids over conventional hydrotreating …

Nanoscale Metal Oxide And Supported Metal Catalysts For Li-Air Battery, Kan Huang

Doctoral Dissertations

"The dissertation work focuses on research and development of durable nanoscale catalysts and supports for rechargeable Li-air batteries that use aqueous catholytes. Transition metal oxides, TiO₂ and Nb₂O₅ in particular, were prepared from a sol-gel process in the form of nanocoatings (5~50 nm) on carbon nanotubes (CNTs) and studied as catalyst supports. Carbon doping in the oxides and post annealing significantly increased their electronic conductivity. Pt catalyst on the support with TiO₂ (Pt/c-TiO₂/CNTs) showed a much better oxygen reduction reaction (ORR) activity than a commercial Pt on carbon black (Pt/C). Negligible loss ( …

Scaleup And Hydrodynamics Study Of Gas-Solid Spouted Beds, Shreekanta Basavaraj Aradhya

Doctoral Dissertations

"A thorough understanding of the complex flow structure of gas-solid spouted bed is crucial for design, scale-up and performance. Advanced gas-solid optical probes were developed and used to evaluate different hydrodynamic parameters of spouted beds. These optical probes measure solids concentration, velocity and their time series fluctuations. Since solids concentration needs to be converted to solids holdup through calibration, for meaningful interpretation of results, a novel calibration method was proposed (which is inexpensive and reliable compared to the current reported methods) and validated in the present study. The reported dimensionless groups approach of spouted bed scale-up was assessed and was …

Catalytic Conversion Of Biomass Derived Syngas To Liquid Fuels Using Fischer-Tropsch Synthesis, Pratibha Sharma

LSU Master's Theses

Biomass gasification and subsequent conversion to liquid hydrocarbons using Fischer-Tropsch synthesis is a promising source of energy in today’s scenario when the focus has shifted from conventional fuels to alternate sources of energy. Biomass derived syngas is different from other sources of syngas such as steam reforming of methane followed by water gas shift, in terms of H2/CO ratio. Biomass syngas is usually hydrogen deficient and contains various impurities which need to be removed prior to Fischer-Tropsch Synthesis. Syngas derived from biomass also differs significantly with the different sources of biomass, gasification process and the cleanup conditions it is subjected …

Analytical Modeling And Diagnosis Of Penetration Rate Performance Of Pdc Bits, Reza Rahmani

LSU Doctoral Dissertations

The high cost of drilling deep (15000+ ft) wells, due to slow rate of penetration (ROP) at depth, has severely limited the utilization and economic significance of deep hydrocarbon resources. The overall objective of this study was to obtain a better understanding of the major cause(s) of slow ROP in deep drilling. An analysis of field data demonstrated the impact of the problem and identified shale and limestone as the primary lithologies where slow ROP occurs at depth. Previous researchers have concluded that interactions between rock, drilling fluid, cuttings, and the bit control ROP. More specifically, several researchers have concluded …

Gas Dynamics And Heat Transfer In A Packed Pebble-Bed Reactor For The 4th Generation Nuclear Energy, Rahman Abdulmohsin

Doctoral Dissertations

"Proper analyses of axial dispersion and mixing of the coolant gas flow and heat transport phenomena in the dynamic core of nuclear pebble-bed reactors pose extreme challenges to the safe design and efficient operation of these packed pebble-bed reactors.

The main objectives of the present work are advancing the knowledge of the coolant gas dispersion and extent of mixing and the convective heat transfer coefficients in the studied packed pebble-beds. The study also provides the needed benchmark data for modeling and simulation validation. Hence, a separate effect pilot-plant scale and cold-flow experimental setup was designed, developed and used to carry …

Knowledge Dictionary For Information Extraction On The Arabic Text Data, Wahyu Syaifullah Jauharis Saputra, Agus Zainal Arifin, Anny Yuniarti

Makara Journal of Technology

Information extraction is an early stage of a process of textual data analysis. Information extraction is required to get information from textual data that can be used for process analysis, such as classification and categorization. A textual data is strongly influenced by the language. Arabic is gaining a significant attention in many studies because Arabic language is very different from others, and in contrast to other languages, tools and research on the Arabic language is still lacking. The information extracted using the knowledge dictionary is a concept of expression. A knowledge dictionary is usually constructed manually by an expert and …

Thermodynamic Kinetics And Efficiency Analysis Of Methyl Viologen, Chang Chen

Theses and Dissertations

Methyl Viologen (MV) is an electron mediator that has great possibilities to be used with an electrode system in which the electrode system provides electrons towards reducing MV species. MV has three redox states and they can be converted to each other via redox reactions on the surface of the electrode. The concentration of the three species of MV was related to the voltage potential applied to the system through a thermodynamic model. With the thermodynamic model the concentration of the three species can be predicted with different applied voltage potentials towards providing guidance for controlling the redox state of …

Novel Iron Catalyst And Fixed-Bed Reactor Model For The Fischer-Tropsch Synthesis, Kyle Martin Brunner

Theses and Dissertations

This work investigates a novel iron Fischer-Tropsch (FT) catalyst preparation and describes the development of a trickle fixed-bed recycle reactor model (TFBRRM) for the FT synthesis applicable to both iron and cobalt catalysts. The iron catalyst preparation was developed using a novel solvent deficient precipitation reaction. Fifteen Fe/Cu/K/SiO2 catalysts were prepared to investigate key preparation variables including timing of promoter addition, washing or not washing after precipitation, and drying temperature. Adding promoters to starting materials before precipitation (1S) gives more uniform promoter distributions which gives higher water-gas shift activity and lower methane selectivity. Unwashed catalysts have smaller average pore and …

Understanding Noble Metal Addition In Cobalt Fischer Tropsch Catalysts, Kari Marie Cook

Theses and Dissertations

The effects of noble metal (NM) promotion and deposition order (co-deposition of NM with the final Co deposition [co-dep] or sequential deposition of NM after Co deposition [seq-dep]) on surface area, pore size, metal retention, crystallite size, noble metal distribution and bonding in Co Fischer Tropsch (FT) catalysts were studied as were the resulting Co reducibility and Fischer Tropsch activity/selectivity properties. Catalysts containing nominally 25wt% Co with either 0.3 wt% Ru, 0.58 wt% Pt, 0.55wt% Re, or no NM on a La-stabilized-Al2O3 support were prepared by wet deposition. The Co, Pt, and Re were uniformly dispersed, but Ru distribution and …

Did Mineral Surface Chemistry And Toxicity Contribute To Evolution Of Microbial Extracellular Polymeric Substances?, Jie Xu, Jay M. Campbell, Nianli Zhang, William J. Hickey, Nita Sahai

College of Polymer Science and Polymer Engineering

Modern ecological niches are teeming with an astonishing diversity of microbial life in biofilms closely associated with mineral surfaces, which highlights the remarkable success of microorganisms in conquering the challenges and capitalizing on the benefits presented by the mineral-water interface. Biofilm formation capability likely evolved on early Earth because biofilms provide crucial cell survival functions. The potential toxicity of mineral surfaces toward cells and the complexities of the mineral-water-cell interface in determining the toxicity mechanisms, however, have not been fully appreciated. Here, we report a previously unrecognized role for extracellular polymeric substances (EPS), which form biofilms in shielding cells against …

Fiber Optic Monitoring Of Subsea Equipment, David Brower, John Hedengren, Cory Loegering, Alexis Brower, Karl Witherow, Karl Winter

Faculty Publications

Bass Lite deepwater field in the Gulf of Mexico, at water depths of approximately 2,050 m (6,750 feet), commenced operation in February 2008. Natural gas is produced from Bass Lite via a 90-km (56-mile) subsea tieback to the Devils Tower Spar. This project involved several innovations, one of which was the incorporation of a fiber optic sensing system that measures realtime temperature, pressure and strain along the pipeline length. This is a first of its kind innovation that is in actual operation.

Innovative Desalination Systems Using Low-Grade Heat, Chennan Li

USF Tampa Graduate Theses and Dissertations

Water and energy crises have forced researchers to seek alternative water and energy sources. Seawater desalination can contribute towards meeting the increasing demand for fresh water using alternative energy sources like low-grade heat. Industrial waste heat, geothermal, solar thermal, could help to ease the energy crisis.

Unfortunately, the efficiency of the conventional power cycle becomes

uneconomically low with low-grade heat sources, while, at the same time, seawater desalination requires more energy than a conventional water treatment process. However, heat discarded from low-grade heat power cycles could be used as part of desalination energy sources with seawater being used as coolant …

Supercritical Co2 Extraction Of Oil From Henna Flower: Experimental, Mathematical Modeling, And Antioxidant Activity, Bushra Saeed Mohammed Dohai

Theses

Henna is a plant that has been used traditionally for coloring nail, skin, and hair, and as medicinal plant. The supercritical fluid technology offers a considerable promise as extraction media due to its advantages over other conventional extraction techniques. The extraction of volatile components from flowers of henna was studied using supercritical carbon dioxide at temperatures and pressures ranging from 35 to 55°C and 80 to 120 bar, respectively. A maximum extraction yield of 31 % from 2g of henna flowers was obtained at 45 °C and 120 bar. The composition of the extracts was investigated by gas chromatography technique. …

Heat Transfer Coefficients In Mimicked Fischer-Tropsch Slurry Bubble Columns, Chengtian Wu, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

To Provide More Support for Fischer-Tropsch (FT) Slurry Bubble Column Reactor Design, Scale-Up, and Performance, the Effects of Operating Conditions on the Heat Transfer Coefficients Were Investigated in a Mimicked FT Cold Flow System (Compressed Air:C 9-C 11:FT Catalyst Carrier). the Studied Operating Conditions Varied in Superficial Gas Velocity (Up to 0.3 M/s), Pressure (Up to 10 Bar), and Solids Concentration (Up to 25 Vol %). the Effects of These Variables on Heat Transfer Coefficients Are Discussed and Analyzed. the Increase in Pressure Tended to Reduce the Heat Transfer Coefficient, While the Increase in Solids Loading Enhanced the Heat Transfer …

The Potential Of Industrial Waste And Agricultural Feedstock Towards Sustainable Biofuels Production: Techno-Economic And Environmental Impact Perspectives, Felix K. Adom

Dissertations, Master's Theses and Master's Reports - Open

This Ph.D. research is comprised of three major components; (i) Characterization study to analyze the composition of defatted corn syrup (DCS) from a dry corn mill facility (ii) Hydrolysis experiments to optimize the production of fermentable sugars and amino acid platform using DCS and (iii) Sustainability analyses. Analyses of DCS included total solids, ash content, total protein, amino acids, inorganic elements, starch, total carbohydrates, lignin, organic acids, glycerol, and presence of functional groups. Total solids content was 37.4% (± 0.4%) by weight, and the mass balance closure was 101%. Total carbohydrates [27% (± 5%) wt.] comprised of starch (5.6%), soluble …

Biofuels Production From Hydrotreating Of Vegetable Oil Using Supported Noble Metals, And Transition Metal Carbide And Nitride, Huali Wang

Wayne State University Dissertations

The focus of this research is to prepare non-sulfided hydrotreating catalysts, supported noble metal and transition metal carbide/ nitride, and evaluate their hydrocracking activities and selectivities by using soybean oil as the feedstock. For comparison study, catalytic cracking of soybean oil over a commercialized ZSM-5 was investigated. However, steady state could not be reached because significant amounts of tar and coke were generated during the reaction though a high yield (21%) of jet fuel was obtained from the process. Compared to the catalytic cracking process, less tar and coke were formed during the hydrocracking process and stable continuous flow reaction …

Development Of Strategies To Minimize The Release Of Trace Elements From Coal Waste Sources, Mohammad Rezaee

Theses and Dissertations--Mining Engineering

To assess strategies aimed at minimizing the release of trace elements and the impact of disposal of coal waste materials on the environment, two long-term leaching experiments of up to five months duration were performed using waste materials from two plants cleaning high and low sulfur bituminous coal. The tests evaluated the mobility of major trace elements under different disposal scenarios: (i) a static leaching test designed to simulate the quiescent conditions encountered by coal waste material stored under water in a stable impoundment, and (ii) a dynamic test to simulate waste materials exposed to the atmosphere, either in variable …

Experimental Investigations In Co2 Sequestration And Shale Caprock Integrity, Abiola Olukola Olabode

LSU Master's Theses

More than sixty percent (60%) of conventional hydrocarbon reservoirs which are potential CO2 repositories are sealed by tight shale caprock. The geochemical reactivity of shale caprock during CO2 diffusive transport needs to be included in the reservoir characterization of potential CO2 sequestration sites as slow reactive transport processes can either strengthen or degrade seal integrity over the long term. Several simulation results had predicted that influx-induced mineral dissolution/precipitation reactions within shale caprocks can continuously reduce micro-fracture networks, while pressure and effective-stress transformation first rapidly increase then progressively constrict them. This experimental work applied specific analytical techniques in investigating changes in …

Catalytic Tri-Reforming Of Biomass-Derived Syngas To Produce Desired H2:Co Ratios For Fuel Applications, Devin Mason Walker

USF Tampa Graduate Theses and Dissertations

This study focuses on upgrading biomass derived syngas for the synthesis of liquid fuels using Fischer-Tropsch synthesis (FTS). The process includes novel gasification of biomass via a tri-reforming process which involves a synergetic combination of CO2 reforming, steam reforming, and partial oxidation of methane. Typical biomass-derived syngas H2:CO is 1:1 and contains tars that deactivate FT catalyst. This innovation allows for cost-effective one-step production of syngas in the required H2:CO of 2:1 with reduction of tars for use in the FTS. To maximize the performance of the tri-reforming catalyst, an attempt to control oxygen mobility, thermal stability, dispersion of metal, …

Aggregation Of Sediment And Bacteria With Mucilage From The Opuntia Ficus-Indica Cactus, Audrey Lynn Buttice

USF Tampa Graduate Theses and Dissertations

Flocculants are commonly used in industrial settings where solid-liquid separations are desired including industrial and municipal wastewater management and potable water production facilities. Conventional flocculants include inorganic metal salts and synthetic organic polymers. The cost, availability, and harmful effects of the non-biodegradable nature of these flocculants have led to the widespread study of natural flocculants. Current natural flocculants being studied include polysaccharides cultivated from microbial extracellular matrix products and plant based materials. In this study, the mucilage of Opuntia ficus-indica cactus was evaluated as a natural flocculant for sediments and bacteria. The O. ficus-indica cactus is also known as the …

Electrospun Chitosan Nanofibers For Virus Removal, Bingyu Bai

Dissertations, Master's Theses and Master's Reports - Open

Electrospinning uses electrostatic forces to create nanofibers that are far smaller than conventional fiber spinning process. Nanofibers made with chitosan were created and techniques to control fibers diameter and were well developed. However, the adsorption of porcine parvovirus (PPV) was low. PPV is a small, nonenveloped virus that is difficult to remove due to its size, 18-26 nm in diameter, and its chemical stability. To improve virus adsorption, we functionalized the nanofibers with a quaternized amine, forming N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride (HTCC). This was blended with additives to increase the ability to form HTCC nanofibers. The additives changed the viscosity …

Glycerin Reformation In High Temperature And Pressure Water, Jason W. Picou

Doctoral Dissertations

"The noncatalytic reformation of glycerin in supercritical water was studied in a Haynes 282 tubular reactor. In order to determine which parameters were the most influential, a 2³ experimental matrix was conducted, with temperatures of 500 and 700⁰C, water/glycerin molar ratios of 3:1 and 13:1, and residence times of 30 and 90 seconds, all at a pressure of 24 MPa. It was found that temperature had the largest effect on the two gasification parameters deemed most important, gasification percentage and hydrogen yield. Based on this, the effect of temperature was further investigated by looking at 5⁰C intervals from 500 to …

Description Of Pressure Fluctuations In A Circulating Fluidized Bed By Statistical Analysis, Adam Luckos, Roelof Coetzer, Andre Mostert

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

In this paper we evaluate different methods for statistically analyzing the variability in pressure fluctuations measured at three locations in an 80-mm-ID, 5-m-tall CFB model operated with natural rutile particles and air at ambient conditions. The methods evaluated are the Shannon entropy, Fischer information matrix together with kernel density estimation, and an estimation of the magnitude of the pressure amplitudes. The accuracy of the different methods is estimated by the bootstrap method. We illustrate how informative statistics from these methods can be used to quantify the effect of the process variables on fluidization at different bed locations. Depending on the …

Oxy-Combustion Of Different Coals In A Circulating Fluidized Bed, Adam Luckos, Monika Kosowska-Golachowska, Konrad Klos, Tomasz Musial

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Combustion of three Polish and one South African bituminous coal particles in air versus O2/CO2 mixtures with oxygen concentrations in the range from 21% to 60% vol. was conducted at temperature of 850°C in a 12 kW bench-scale CFB combustor. Combustion in air was proceeded at ~50˚C higher centre temperatures and was slightly shorter in time compared to combustion in O2/CO2 mixture with 21% vol. O2. Larger heat capacity of CO2 compared to that of N2 also retards the ignition of volatiles in O2/CO2 mixtures with 21% O2. However, when the concentration of oxygen in O2/CO2 mixtures is larger than …

Bio-Gasoline From Jatropha Oil: New Applications For The Fcc- Process, Alexander Weinert, Alexander Reichhold, Peter Bielansky, Christoph Schönberger, Bettina Schumi

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Jatropha curcas L. is a very drought-resistant plant, and jatropha oil can be ex-tracted from its seeds. Whilst not suitable for human consumption, we found that it is a promising feedstock for producing (bio)-gasoline. The oil was cracked in an inter-nally circulating FCC-reactor using a Grace Davison Ultima® catalyst. The total con-version was around 65%, with ca. 40% gasoline and ca. 25% crack gas (exact num-bers varied with reactor temperature). The gasoline has a RON > 95 and oxy-gen < 0.3% m. The crack-gas consisted of ca. 35% propylene, ca. 13% 1-butene and ca. 6% ethylene.