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.
Wet oxidation for industrial waste treatment
For those wastes that are not biotreatable, wet oxidation is an economically attractive method of treatment in reducing oxygen demand and altering the biotreatability. Further, when biological treatment changes are based on COD, the cost of wet oxidation is not much greater than typical municpal industrial changes.
Kinetic evaluation and characterization of ceramic honeycomb-monolith bioreactor
Abstract Escherichia coli with γ-galactosidase activity or Saccharomyces cerevisiae was immobilized within a thin κ-carrageenan gel film on a ceramic honeycomb-monolith. The characteristics of the monolith bioreactor were evaluated for reaction systems with and without gas evolution. Under various operational conditions, the Peclet number was found to be nearly constant (Pe=6.6) in both reactions systems. Moreover, the Sherwood number was estimated in terms of Reynolds numbers on superficial liquid and gas velocities. The kinetic analysis based upon the dispersion model and liquid film resistance was done to assess the conversion degree of the substrate in the reactor. In ethanol fermentation accompanied by CO2 gas evolution, as a result, the monolith bioreactor was expected to convert much of the substrate.