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Reactor Productivity (reactor + productivity)
Selected AbstractsPropylene polymerization in a semibatch reactor.POLYMER ENGINEERING & SCIENCE, Issue 12 2001Analysis of soluble metallocene catalyst behavior through reactor modeling We study the process involved in metallocene activation and further propylene polymerization. In this paper, we begin by analyzing the behavior of soluble metallocene in propylene polymerization before advancing to the study of the heterogeneous polymerization. Experimental data obtained in a semibatch laboratory polymerization reactor using ethylenbisindenylzirconium dichloride (EtInd2ZrCl2)/ methylaluminoxane (MAO) are combined with a mathermatical model providing useful information such as number of active sites and their activation patterns. We present a mathematical model for the reactor that predicts not only reactor productivity but also the molecular properties of the product. We apply the model to soluble systems in order to find the optimal parameters for the catalyst itself and in the presence of different types of additives such as aluminum chloride (AlCl3) and ethyl benzoate (E.B.). [source] Biotransformation of R -2-hydroxy-4-phenylbutyric acid by D -lactate dehydrogenase and Candida boidinii cells containing formate dehydrogenase coimmobilized in a fibrous bed bioreactorBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2005Yunling Bai Abstract R -2-hydroxy-4-phenylbutyric acid (R-HPBA) is an important intermediate in the manufacture of angiotensin converting enzyme inhibitors. In this work, a recombinant D -lactate dehydrogenase (LDH) was used to transform 2-oxo-4-phenylbutyric acid (OPBA) to R-HPBA, with concomitant oxidation of ,-nicotinamide adenine dinucleotide (NADH) to NAD+. The cofactor NADH was regenerated by formate dehydrogenase (FDH) present in whole cells of Candida boidinii, which were pre-treated with toluene to make them permeable. The whole cells used in the process were more stable and easier to prepare as compared with the isolated FDH from the cells. Kinetic study showed that the reaction rate was dependent on the concentration of cofactor, NAD+, and that both R-HPBA and OPBA inhibited the reaction. A novel method for co-immobilization of whole cells and LDH enzyme on cotton cloth was developed using polyethyleneimine (PEI), which induced the formation of PEI,enzyme,cell aggregates and their adsorption onto cotton cloth, leading to multilayer co-immobilization of cells and enzyme with high loading (0.5 g cell and 8 mg LDH per gram of cotton cloth) and activity yield (,>,95%). A fibrous bed bioreactor with co-immobilized cells and enzyme on the cotton cloth was then evaluated for R-HPBA production in fed-batch and repeated batch modes, which gave relatively stable reactor productivity of 9 g/L,·,h and product yield of 0.95 mol/mol OPBA when the concentrations of OPBA and R-HPBA were less than 10 g/L. © 2005 Wiley Periodicals, Inc. [source] Modeling Stability of Photoheterotrophic Continuous Cultures in PhotobioreactorsBIOTECHNOLOGY PROGRESS, Issue 4 2003Jean-François Cornet Continuous cultures of the purple non-sulfur bacterium Rhodospirillum rubrum were grown in a cylindrical photobioreactor in photoheterotrophic conditions, using acetate as carbon source. A new kinetic and stoichiometric knowledge model was developed, and its ability to simulate experimental results obtained under varying incident light fluxes and residence times is discussed. The model accurately predicts the stable, unstable, or oscillating behavior observed for the reactor productivity. In particular, the values of residence time corresponding to a subcritical bifurcation with a typical hysteresis effect are calculated and analyzed. The robustness of the proposed model allows the engineering operating domain of the photobioreactor function to be set and offers a promising tool for the design and control of such photoheterotrophic processes. [source] Model-Aided Design of a Three-Phase Gas-Lift Reactor for Oxidation Accompanied by Catalyst Reversible DeactivationCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 12 2009Z. Gogová Abstract A mathematical model of a three-phase gas-lift reactor (GLR) is developed to aid the design of a target reactor for simultaneous substrate catalytic oxidation in riser and a deactivated reactivation catalyst in the downcomer section of the multifunctional reactor. In the GLR model, the hydrodynamics of a real GLR and the kinetics of glucose oxidation by air over a palladium catalyst are incorporated. The GLR model searches for the optimal geometry of the target reactor. With regard to the GLR optimal geometry, the reactor productivity is maximal for given input operational conditions. An algorithm of the GLR model is presented together with simulation results of the target GLR and with insight into the parametric sensitivity of the model. Effects of the reaction components concentrations and the gas-phase superficial velocity on the location of the target reactor optimal geometry and on the reactor productivity are discussed. [source] | ||||||||||