Development of the Monolith Froth Reactor for Catalytic Wet Oxidation of CELSS Model Wastes
The aqueous phase oxidation of acetic acid, used as a model compound for the treatment of CELSS (Controlled Ecological Life Support System) waste, was carried out in the monolith froth reactor which utilizes two-phase flow in the monolith channels. The catalytic oxidation of acetic acid was carried out over a Pt/Al2O3 catalyst, prepared at The University of Tulsa, at temperatures and pressures below the critical point of water. The effect of externally controllable parameters (temperature, liquid flow rate, distributor plate orifice size, pitch, and catalyst distance from the distributor plate) on the rate of acetic acid oxidation was investigated. Results indicate reaction rate increased with increasing temperature and exhibited a maximum with respect to liquid flow rate. The apparent activation energy calculated from reaction rate data was 99.7 kJ/mol. This value is similar to values reported for the oxidation of acetic acid in other systems and is comparable to intrinsic values calculated for oxidation reactions. The kinetic data were modeled using simple power law kinetics. The effect of "froth" feed system characteristics was also investigated. Results indicate that the reaction rate exhibits a maximum with respect to distributor plate orifice size, pitch, and catalyst distance from the distributor plate. Fundamental results obtained were used to extrapolate where the complete removal of acetic acid would be obtained and for the design and operation of a full scale CELSS treatment system.
Bubble-train flow in capillaries of circular and square cross section
Abstract Ceramic monoliths first developed for their use in automotive catalyst, are used now to perform three-phase, catalyzed reactions. The large mass transfer rates achieved within this type of reactor are the result of large interfacial area and very thin diffusion paths. These enhanced mass transfer rates are credited to the presence of well-developed bubble-train flow. Bubble-train flows consist of trains of long bubbles separated by liquid slugs. The interfacial area is the area of the bubbles and the thin films are the result of the squeezing action of the bubbles as they overtake the liquid slugs. The objective of this paper is to predict the main mass transfer parameters, such as bubble size and shape, bubble velocity, and volume fraction of gas inside capillaries of circular or square cross section, on the basis of the superficial flow rates of gas and liquid in the feed. Experiments are reported here on bubble train flow inside capillaries of circular and square cross section for a large range of capillary numbers. A mass balance model was developed to allow the computation of flow parameters using an iteration scheme.
History of Amateurism in Men's Intercollegiate Athletics: The Continuance of a 19th-Century Anachronism in America
Claiming that American intercollegiate athletics are amateur at the end of the 20th century is an anachronism, for colleges in the 19th century took on professional characteristics. The upper-class British concept of amateurism did not work effectively in a more egalitarian and achievement-oriented American society. Hypocrisy resulted when colleges claimed amateurism while accepting such professional practices as hiring professional coaches, allowing athletes to play summer baseball for money, and paying athletes through grants-in-aid. Attempts to preserve amateurism, such as the Graham Plan in the 1930s and the Sanity Code in the 1940s and 1950s, yielded to the professional spirit. Thus, while Americans had generally rejected the upper-class British social hierarchy that fostered amateurism, they retained the name amateur, continuing the hypocrisy that had begun in the previous century.