Engineering Commons^™

Second Law Analysis Of Active Magnetic Regenerative Hydrogen Liquefiers, L. Zhang, S. A. Sherif, T. N. Veziroglu, John W. Sheffield

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Recent published work in the area of magnetic refrigeration reports on its potential for greater efficiency and high reliability. This paper presents an exergy analysis of a three-stage active magnetic regenerative (AMR) hydrogen liquefier which cools a hydrogen gas stream at 77 K and 1 atm to hydrogen liquid at 20 K. Ortho - para conversion of hydrogen is accomplished in a heat exchanger employing a 10 atm helium fluid that cycles in the refrigerator. The performance of the system is described in terms of the cooling capacity and exergy losses as functions of the magnetic material type, magnetic bed …

Hydrogen Diffusion, Solubility, And Water Uptake In Dow's Short-Side-Chain Perfluorocarbon Membranes, Yu-Min Tsou, M. C. Kimble, Ralph E. White

Faculty Publications

Hydrogen gas diffusion coefficients and solubilities as well as water uptake values are reported for Dow's short-side-chain perfluoro-sulfonic and -carboxylic membranes of different equivalent weight (EW). The diffusion coefficients and solubilities were determined with an electrochemical test cell. Hydrogen solubility decreases with increasing EW in the lower EW range and tends to level off at higher EWs for both types of membranes. Both hydrogen solubility and diffusion coefficients of a sulfonic membrane with EW higher than 800 are higher than the corresponding values of a carboxylic membrane of similar EW. An unusual maximum is observed in the diffusion coefficient-EW plot …

Kinetic Mechanism Of The Reactions Of Dichloromethane And Chloroform With Atomic Hydrogen At Low Pressure And Room Temperature, Jia-Ling Linda Young

Theses

The reaction mechanism of dichloromethane reaction (DCM) with atomic hydrogen in a flow reactor at room temper¬ature (300 K) and low pressure (2.1 - 2.7 torr), argon bath gas, has been developed in this research to analyze the above reaction system. The important addition reactions of radicals (or atoms) to olefins and the radical/radical (atom/radical) combination reactions have been analyzed using the bimolecular version of the Quantum-Rice-Ramsperger-Kassel (QRRK) theory.

The detailed reaction mechanism satisfactorily fits the experimental data for the reagent (DCM) conversion from previous experimental over a initial ratio (atomic hydrogen to dichloromethane) range of 6.8 to 40. The …

Thermal Decomposition Of Chlorobenzene Reaction With Hydrogen And Oxygen Mixture In An Atmosphere, Chun-Chen Yang

Theses

The thermal reactions of chlorobenzene in hydrogen and oxygen mixtures were studied in tubular flow reactors at 1 atmosphere total pressure. Experiments were carried out in flow reactors of varied diameter for determining effects of different surface to volume ratios. Residence times ranged from 0.03 to 2.5 seconds and temperature was varied over a range of 560 - 660 °C. The 02/H2 ratios ranged from 1% to 5%.

It was found that the conversion of chlorobenzene in hydrogen and oxygen mixtures increased with both temperature and residence time. The oxidation of chlorobenzene also occurred more rapidly when oxygen concentraction was …

Formation Of Light Hydrocarbons And Soot In The Pyrolysis Reactions Of Chloro, Dichlorobenzene, Acetylene And Benzene In An Atmosphere Of Hydrogen, Larry Jiyuan Zhu

Theses

The kinetics of thermal decomposition of chlorobenzene and dichlorobenzene in a hydrogen and helium atmosphere were further studied to investigate formation of soot and light hydrocarbons. The experiments were performed at atmosphere pressure with residence times rangeing from 0.2 to 1.2 seconds, and the temperature ranges of 850°C to 925°C for chlorobenzene and 870°C to 910°C for dichlorobenzene. Flame ionization detectors, which were connected to GC columns, were utilized for the qualitative and quantitative analysis of the reaction products. A methyl silicone capillary column was used analyzing of heavy aromatics and a Carbosive G was used to analyze light hydrocarbons. …

Hydrogen For Power Applications. Task 2: Storage Of Hydrogen In Solid, Liquid And Gaseous Forms. June 1988. 1 V., Florida Solar Energy Center, David Block

FSEC Energy Research Center®

This report provides a comprehensive account of the major developments and the issues of concern in the storage and handling of hydrogen in all three forms, namely, solid (as metal hydrides), liquid and gaseous. Keeping in mind that ground transportation has the potential to be the most obvious and widespread utilization vector for hydrogen, particular effort is made to compare alternative storage and handling systems of hydrogen with that of gasoline. Conclusions and recommendations are based on a systematic and unbiased analysis of the pros and cons of various storage and handling options for hydrogen, both demonstrated and projected.

Electrodeposition Of Copper-Nickel Alloys From Citrate Solutions On A Rotating Disk Electrode, Ramona Y. Ying, Patrick K. Ng, Z. Mao, Ralph E. White

Faculty Publications

A mathematical model is developed to simulate the electrodeposition of Cu-Ni alloy from citrate solutions onto a rotating disk electrode under potentiostatic control. The model includes the influence of diffusion, ionic migration, forced convection, and homogeneous equilibria. The three major electrochemical reactions treated in the model are copper deposition, nickel deposition, and hydrogen evolution. Using experimental parameters when available, the model was fitted and tested against experimentally-obtained results for different bath compositions and operating conditions. The model agreed reasonably well with the experimental results particularly in the codeposition region, –1.0 to –1.2V vs. SCE, where hydrogen evolution is not the …

Reactions Of Atomic Hydrogen With Dichloromethane In A Flow System, Shun-Hsien Huang

Theses

The reaction kinetics of atomic hydrogen with dichloromethane were studied in a tubular flow reactor with 2.6 cm I.D. Pyrex tube at pressure of 2.1 to 2.7 torr absolute and room temperature . Hydrogen atoms were generated by a microwave discharge plasma. Atomic hydrogen concentration were measured by chemiluminescence titration with nitrogen dioxide. The concentrations of hydrogen atom ranged from 2.0 * 10¹⁴ to 5.0 * 10¹⁵ atoms per cm³. Chlorocarbon reagent and products were monitored by online gas chromatography (FID).

Major products observed were hydrogen chloride and methane. The conversion of dichloromethane increases first to …

Reaction Of Hydrogen With Methylene Chloride And Carbon Tetrachloride At High Temperature, Hun Tsao

Theses

The reactions of methylene chloride and carbon tetrachloride in hydrogen in the temperature range 500 - 1000° C were studied using tubular flow reactors of three diameters. (ID: 0.40, 1.05, 1.60 cm). Residence time range was from 0.3 to 3.5 seconds. Temperature profiles of the reactors was kept within +/- 5° C of central 85% for the 18 inch long reactor, at a total pressure of 1 atmosphere. No chlorinated hydrocarbon products were observed at or above 950° C. The major products in this temperature range were CH4, C2H₂, C2H₄, C2H₆ and HCl.

The pseudo …

Thermal Decomposition Of Chlorobenzene In An Atmosphere Of Hydrogen, Edward Robert Ritter

Theses

The thermal decomposition of chlozobenzene was investigated in a tubular flow reactor at 1 atmosphere total pressure and average residence times of 0.02 - 2.5 seconds. The temperature range from 800 - 1010°C was studied in both a reductive atmosphere of hydrogen and an inert atmosphere of heIium. Complete destruction of chlorobenzene occurs at about 1000°C for an average residence time of 1 second in hydrogen gas. In the inert gas, the complete destruction of the reagent was not observed in the range of conditions which were studied. The major products observed for pyrolysis in hydrogen were benzene, HCl, and …

Reactions Of Hydrogen With Chloroform And Trichloroethylene At High Temperatures, Burhan Mahmood

Theses

The reactions of chloroform and trichloroethylene with hydrogen in the temperature range 550 to 1000°C were studied using tubular flow reactors of varying diameters. The residence time range was from 0.05 to 3.0 seconds.Two different concentrations of the chlorinated species were used, each with hydrogen in large excess. Flat temperature profiles (+/- 5°C) were achieved over 80 to 85 per cent of the 45 cm long reaction zone, with inlet gases preheated to about 400°C.

No chlorinated hydrocarbons, products or reactants were observed at /above 850°C. The major products at these temperatures were C₂H₂, C_{2 …}

Effect Of Hydrogen Bonding And Ionic Aggregation On The Melt Rheology Of An Ethylene-Methacrylic Acid Copolymer And Its Sodium Salt, William Macknight, T. R. Earnest Jr.

William MacKnight

No abstract provided.

Wind-Powered Hydrogen Electric Systems For Farm And Rural Use, Final Report, United States Department Of Energy

Agriculture

The objective of this study has been to determine the current technology of a wind-energy conversion system (WECS) of minimal cost for rural applications. Specifically, IGT has evaluated available methods for converting shaft horse-power from a wind turbine to electricity and hydrogen. A workable mix of these two energy forms with storage that can support the energy needs of selected farming operations and the rural home was sought.

Energy load patterns of several farming operations were examined for interfacing with the energy storage and delivery systems that are supplied by wind turbines dependent on the prevalent winds. Several preliminary designs …

Hydrogen Overvoltage Of Cadmium Bismuth And Antimony Bismuth Alloys, Edwin W. Stevens

Bachelors Theses and Reports, 1928 - 1970

A method to measure hydrogen overvoltage was devel­oped and checked with metals of known overvoltage. Alloys of bismuth and antimony and of bismuth and cad­mium were prepared and their overvoltages determined.

The Measurement Of Current Efficiency In Zinc Sulphate Electrolytes Containing Antimony And Cobalt By Hydrogen Evolution, Arthur R. Hard

Bachelors Theses and Reports, 1928 - 1970

The measurement of current efficiency by hydrogen evolution is based on the assumption that the portion of the current which deposits no zinc will release hydrogen. This assumption is correct for solutions containing no impurities electropositive to zinc.

The Effect Of Hydrogen Overvoltage On The Electrolytic Deposition Of Zinc, John M. Munzenrider, Kenneth O. Sweeney

Bachelors Theses and Reports, 1928 - 1970

In the deposition of metallic zinc by electro­lysis from neutral or acid solution, little difficulty is experienced provided certain impurities are absent from the electrolyte. The use of the process has long been considered as a potential source, patents on the process having been issued as early as 1880. However, the early experimenters failed to realize the importance of impurities in the electrolyte, and for this reason, the process suffered several severe setbacks when commercial plants were built.

The Electrical Resistance Of Metals And Alloys In Their Hard And Soft States, Noah David Gerchesvky, Charles Becker Hoskins

Bachelors Theses and Reports, 1928 - 1970

It is known that the electrical resistance of annealed metals is usually smaller than that of metals in their cold worked state. The curve showing the relation between electrical resistance and annealing temperature reaches a minimum; continued annealing at higher temperature produces an increase in the electrical resistance. In the case of alloys it has been noted that a second decrease occurs at higher annealing temperature.

The following work corroborates the observance of previous investigations. The electrical resistance of cold worked copper, gold, nickel, and iron decreased with annealing and then increased, the minimum being around 300° C. or 400° …