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Batch Operation (batch + operation)
Selected AbstractsEnhanced production of lovastatin in a bubble column by Aspergillus terreus using a two-stage feeding strategyJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2007EM Rodríguez Porcel Abstract A two-stage feeding strategy is shown to improve the rate of production of lovastatin by Aspergillus terreus when compared with conventional batch fermentation. The feeding strategy consisted of an initial batch/fed-batch phase and a semi-continuous culture dilution phase with retention of pelleted biomass in a slurry bubble column reactor. The batch phase served only to build up the biomass for producing lovastatin, a secondary metabolite that inhibits its own synthesis in the producing microfungus. The semi-continuous dilution phase provided nutrients to sustain the fungus, but prevented biomass growth by limiting the supply of essential nitrogen. (Synthesis of lovastatin does not require nitrogen.) The preferred pelleted growth morphology that favors lovastatin synthesis was readily obtained and maintained in the 20 L bubble column used. In contrast, a stirred tank fermentation had a substantially lower production of lovastatin because mechanical agitation damaged the fungal pellets. The two-stage feeding method increased lovastatin production rate by more than 50% in comparison with the conventional batch operation. Rheological data for the fungal broth are presented. Copyright © 2007 Society of Chemical Industry [source] Removal characteristics of some priority organic pollutants from water in a fixed bed fly ash columnJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 12 2005Mitali Sarkar Abstract The efficiency of a coal fly ash (generated from a thermal power plant) adsorption column for the removal of some priority organic pollutants, viz phenol, o -hydroxyphenol, m -hydroxyphenol and 4-nitrophenol from aqueous solution has been studied. The column performance was evaluated from the concept of the formation of a primary adsorption zone and the breakthrough curve. The extent of solute removal obtained from breakthrough curve during column operation was compared with that obtained from the isotherm parameters for batch operation. The loaded solutes in the column were successfully eluted with acetone, achieving 98% recovery. In order to determine the practical applicability of the column operation the process was repeated a number of times and the variation of column capacity with number of operation cycles was evaluated. Even after six successive cycles, the column was found to retain almost 80% capacity. Copyright © 2005 Society of Chemical Industry [source] Determination of membrane areas for ultrafiltration processesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2001Changsheng Liu Abstract For batch mode ultrafiltration processes a numerical method for calculating membrane area has been devised with flux predicted from Flemmer's model. Erythromycin broth filtrate was used as a model fluid. Experiments at a 20,dm3 scale were used to estimate the parameters involved in Flemmer's equation, from which membrane areas appropriate for operations of 80 metric tons were calculated. Factors such as rejection, concentration ratio, etc, which affect the membrane size for batch operation, are discussed. The calculated results were consistent with experimental data at the 100,dm3 scale. For continuous operation equations for calculating membrane areas have also been established. The minimum membrane area was calculated at the optimum concentration ratios of each stage, usually their values were different at each stages. Comparison between batch and continuous mode in the context of the membrane area required is also discussed. The method could be applicable to other ultrafiltration operations. © 2001 Society of Chemical Industry [source] Centrifugal drum filtration: I. A compression rheology model of cake formationAICHE JOURNAL, Issue 2 2006John D. Barr Abstract A compression rheology model is used to describe the behavior of networking solids undergoing centrifugal filtration under batch operation. A description of the batch filtration process is accomplished through the use of the rheologic functions for compressive yield stress py(,) and the hydrodynamic resistance R(,), with a characteristic pressure scaling, timescaling, and membrane resistance. Comparison of the results of this model to those found in engineering text books indicates that noncompression models fail to describe the variation in the cake resistance. The compression rheology model also predicts that the effective cake resistance is approximately 20% larger than that predicted by conventional theory. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source] | ||||||||||