A mathematical modeling framework for the methane steam reforming reaction operating in steady state has been developed. Performances are compared between the classic catalytic packed bed reactor and a Pd-based catalytic membrane reactor. Isothermal simulations on MATLAB © has first been conducted and show a higher performance of the membrane reactor over the packed bed reactor. Methane conversion of 1 can be reached for lower temperatures than used with industrial PBR, and better performances are shown for an increase in the operating pressure. Optimum conditions were defined for Temperature (500-600 Celsius), reaction side pressure (16-40 bars), membrane thickness (1-7 micrometers), steam/methane ratio (3-4), reactor length (5-10 meters) and permeate sweep ratio (20 or more). This model was validated by multiple recognized sources. Adiabatic simulations were conducted in order to develop a mathematical model base for non-isothermal simulations. The membrane reactor is again showing a higher conversion of methane compared to the packed bed reactor, however the heat loss due to the membrane and the hydrogen leaving through the tube is decreasing the performances of the MR over the PBR compared to the isothermal case. Results show also that most of the reaction occurs at the very beginning of the reactor.

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Thesis (Ph. D.)--School of Computing and Engineering and Dept. of Mathematics and Statistics. University of Missouri--Kansas City, 2005. / "A dissertation in engineering and mathematics." Advisor: Bryan R. Becker. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed March 12, 2007. Includes bibliographical references (leaves 216-220). Online version of the print edition.

An experimental study on flooding with steam and water in a large diameter vertical tube was conducted. This research has been performed to provide a better prediction of flooding in a pressurized water reactor (PWR) pressurizer surge line to be used in reactor safety codes. Experiments were conducted using a 3-inch (76.2 mm) diameter tube 72 inches (1.83 m) long with subcooled water and super-heated steam at atmospheric pressure as the working fluids. Water flows down the inside walls of the tube as an annulus while the steam flows upward in the middle. The water flow rates ranged from 3.5 to 12 gallons per minute (GPM) (0.00022 to 0.00076 m^3/s) and the water inlet temperature was approximately 70 degrees C. The steam inlet temperature was approximately 110 degrees C. The size of the test section as well as the flow ranges of the working fluids was determined based on a scaling analysis of a PWR pressurizer surge line. Two distinct trends were observed in the data. It was found that for water flow rates below 6 GPM (0.00038 m3/s) the amount of steam required for flooding to occur decreases with an increasing water flow rate. For water flow rates above 6 GPM the amount of steam required for flooding to occur increases with an increasing water flow rate. In addition, axial water temperature data was collected. Axial water temperatures have not been recorded in previous flooding experiments with steam and water. A new correlation for predicting flooding with steam and water was proposed. This correlation was an improvement from previous correlations because it included the amount of steam condensation. Incorporation of steam-water mass exchange promotes a better prediction of behavior in reactor systems. This data for flooding with steam and water in a large diameter vertical tube can lead to a mechanistic model for flooding.

Experiments were conducted to investigate the feasibility of in situ upgrading of heavy oil by the use of an orgametallic catalyst and a hydrogen donor (tetralin). The experiments used a vertical injection cell into which a mixture of sand, water, and Jobo oil was thoroughly mixed and packed. Two types of runs were conducted: a run where the tetralin and catalyst were mixed within the mixture before packing into the cell, and the other was conducted by injecting a slug of the tetralin-catalyst solution before commencing with the steam injection. The Jobo oil used had an oil gravity of 12.4° API and a viscosity of 7800 cp at 30°C. The injection cell was placed in a vacuum jacket and set to a reservoir temperature of 50°C. Superheated steam at 273°C was then injected into the injection cell at a rate of 5.5 cc/min (cold water equivalent). The cell outlet pressure was maintained at 500 psig. Produced liquid samples were collected periodically through a series of separators. The produced oil was divided into two halves and several measurements and analyses were carried out on them. These included viscosity, density, elemental analysis and liquid composition. Experimental results indicated that tetralin alone was a worthy additive and increased recovery by 15% compared to that of pure steam. The premixed tetralincatalyst run showed improved recovery to that of pure steam by 20%. Experiments also showed that, when the tetralin-catalyst solution was injected rather than mixed, the results were equivalent to tetralin injection runs. Oil production acceleration was displayed by all the runs with tetralin and tetralin-catalyst but was more pronounced with the availability of catalyst.

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Condensation, of steam bubbles generated at an orifice and rising freely through water, subcooled from 5 K to 36.6 K at pressures of 1 bar and 2 bar, has been analysed theoretically and experimentally. Orifice diameters were 1 mm and 2 mm, and steam flow rates of 0.5, 1 and 1.5 g/min were used. The data indicate a decrease in collapse Fourier number with increase in either Jakob number or steam flow rate, or with a decrease in pressure, while change in orifice diameter does not have a significant effect on collapse Fourier number. Average values of heat transfer coefficient around the collapsing bubbles have been determined to be between 0.15 . 10⁵ - 0.35 . 10·⁵ W/m·²K. The effect of bubble distortion and of local heating of the liquid, close to the orifice, due to condensation of the bubbles, have both been included in the quasi-steady state theory which has been presented. The experimental data is compared with the theoretical predictions. A semi-empirical correlation for bubble rise height has been proposed, which is also based on the quasi-steady theory combined with a correlation for the velocity of steam bubbles condensing in subcooled water.

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