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Scale-up
Kinds of Scale-up Terms modified by Scale-up Selected AbstractsSCALE-UP and FIELD TEST of the VACUUM/STEAM/VACUUM SURFACE INTERVENTION PROCESS FOR POULTRY,JOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2003MICHAEL KOZEMPEL ABSTRACT The Vacuum/Steam/Vacuum surface intervention pilot plant processor was scaled up to a mobile unit that can be transported to close proximity of chicken processing plants. After several modifications to the mandrel that supports the broiler carcass in the treatment chamber to minimize mechanical damage, the unit was capable of 1.1 log cfu/mL kill of inoculated Listeria innocua and 1.4 log cfu/mL kill of inoculated E. coli K-12. Field tests achieved 1.4 log kill of E. coli and 1.2 log kill of Campylobacter on freshly processed chicken using 3 cycles and 138C saturated steam. But, there was extensive mechanical damage. the mandrel was modified in the Eastern Regional Research Center pilot plant to eliminate the mechanical damage. With mechanical damage eliminated, the bacteria kill was 1.1,1.5 log of inoculated E. coli K-12 with a total process time of 1.1 s. [source] MODELING HEAT EFFICIENCY, FLOW AND SCALE-UP IN THE COROTATING DISC SCRAPED SURFACE HEAT EXCHANGERJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2002ALAN FRIIS ABSTRACT A comparison of two different scale corotating disc scraped surface heat exchangers (CDHE) was performed experimentally. The findings were compared to predictions from a finite element model. We find that the model predicts well the flow pattern of the two CDHE's investigated. The heat transfer performance predicted by the model agrees well with experimental observations for the laboratory scale CDHE whereas the overall heat transfer in the scaled-up version was not in equally good agreement. The lack of the model to predict the heat transfer performance in scale-up leads us to identify the key dimensionless parameters relevant for scale-up. [source] Control of the morphology and the size of complex coacervate microcapsules during scale-upAICHE JOURNAL, Issue 6 2009C. Y. G. Lemetter Abstract Scale-up of complex coacervation, a fat encapsulation technology, is not trivial since the microcapsules morphology and size are highly affected by the processing conditions. So far it has been achieved empirically (trial and error approach). The goal of this study was to produce at various scale capsules with a single-oil droplet as the core material and small enough to be below sensory threshold. The turbulence level was identified as the main scale-up criterium and a master-curve could be drafted showing the capsule mean diameter as function of the Reynolds number, independent of the level of production scale. From a parent emulsion with specific oil droplets size (12,15 ,m), the Reynolds number had to be maintained above a critical value (15,000) to avoid capsules agglomeration with multiple oil cores and large particle sizes. To avoid aggregation, this turbulence level had to be kept until the temperature dropped below a critical value (14°C for a cooling rate of 35°C/2 h). Applying these learning led to a successful scale-up from bench (2 L) to a pilot plant scale of 50 L. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Scale-up of molecular sieve silica membranes for reformate purificationAICHE JOURNAL, Issue 10 2004M. Duke First page of article [source] Model for temperature profiles in large diameter electrochromatography columnsAICHE JOURNAL, Issue 2 2003Craig Keim Scale-up of electrochromatographic separations has been problematic due to electrically induced heating. A two-dimensional transient temperature model for electrochromatography was developed, which accounts for physical properties of the stationary and mobile phase, and the column wall. The model also accounts for both the temperature effect on the electrical conductivity and a nonuniform, radially variant current density. This model was compared to experimental data from two electrochromatography systems with different cylindrical-column dimensions, packing materials, and operating conditions. In all cases, the model predicts the temperature to within 3°C of the actual temperature, both for column heatup and cooldown. Separation of a mixture of model proteins on the 3.81-cm-ID scale was used as the basis for scale-up calculations. The model identifies equipment parameters that control heating characteristics and can be scaled up to process 75 mL of sample per run. [source] Large-scale submerged fermentation of Antrodia cinnamomea for anti-hepatoma activityJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2008Jih-Hung Pan Abstract BACKGROUND: Submerged cultivation of Antrodia cinnamomea was carried out for manufacturing the fermentation product with anti-hepatoma activity. The fermentation process was optimized for different parameters at shake flask level to obtain products with high inhibition potency against Hep G2 hepatoma cells. Scale-up of the fermentation process was then achieved from 250 mL shake flask to 5 L, 500 L and 5-ton fermenters. RESULTS: Glucose and malt extract were found to be the best carbon and nitrogen sources, respectively. The initial pH of 5.0 and an operating temperature of 22 °C were the best for a product with lowest IC50 value. A shorter cultivation time was required when the scale of fermentation increased from 5 L to 5 tons. The reducing sugar and solids contents of the broth filtrate were correlated exponentially with the IC50 of the ethanolic extract of mycelium for hepatoma cells, and the level of ergosterol in the mycelium extract follows the same profile as the increase in Hep G2 cells inhibition. CONCLUSION: When Antrodia cinnamomea is cultured in a 5-ton fermenter, 4 weeks are required for the fermentation product to reach the highest anti-hepatoma activity. The solid and reducing sugar contents of the broth filtrate as well as the ergosterol content in the ethanol extract of mycelium can serve as the marker during fermentation for manufacturing product with anti-hepatoma activity. Copyright © 2008 Society of Chemical Industry [source] Scale-up of natural product formation and isolationMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 8 2005Ralf G. Berger [source] Microarray-based gene expression analysis as a process characterization tool to establish comparability of complex biological products: Scale-up of a whole-cell immunotherapy productBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2009Min Wang Abstract Whole-cell immunotherapies and other cellular therapies have shown promising results in clinical trials. Due to the complex nature of the whole cell product and of the sometimes limited correlation of clinical potency with the proposed mechanism of action, these cellular immunotherapy products are generally not considered well characterized. Therefore, one major challenge in the product development of whole cell therapies is the ability to demonstrate comparability of product after changes in the manufacturing process. Such changes are nearly inevitable with increase in manufacturing experience leading to improved and robust processes that may have higher commercial feasibility. In order to comprehensively assess the impact of the process changes on the final product, and thus establish comparability, a matrix of characterization assays (in addition to lot release assays) assessing the various aspects of the cellular product are required. In this study, we assessed the capability of DNA-microarray-based, gene-expression analysis as a characterization tool using GVAX cancer immunotherapy cells manufactured by Cell Genesys, Inc. The GVAX immunotherapy product consists two prostate cancer cell lines (CG1940 and CG8711) engineered to secrete human GM-CSF. To demonstrate the capability of the assay, we assessed the transcriptional changes in the product when produced in the presence or absence of fetal bovine serum, and under normal and hypoxic conditions, both changes intended to stress the cell lines. We then assessed the impact of an approximately 10-fold process scale-up on the final product at the transcriptional level. These data were used to develop comparisons and statistical analyses suitable for characterizing culture reproducibility and cellular product similarity. Use of gene-expression data for process characterization proved to be a reproducible and sensitive method for detecting differences due to small or large changes in culture conditions as might be encountered in process scale-up or unanticipated bioprocess failures. Gene expression analysis demonstrated that cell products of representative lots under the same production process and at the same production scale were statistically identical. Large process changes that resulted from the artificial stress conditions used (absence of FBS and induction of hypoxia) displayed profoundly different gene expression patterns. We propose the use of simple t -test analysis in combination with the herein introduced expression ratio with mean intensity (ERMI) analysis as useful tools for process characterization by global gene expression analysis. Biotechnol. Bioeng. 2009; 104: 796,808 © 2009 Wiley Periodicals, Inc. [source] Scale-up from shake flasks to fermenters in batch and continuous mode with Corynebacterium glutamicum on lactic acid based on oxygen transfer and pHBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2007Juri M. Seletzky Abstract Scale-up from shake flasks to fermenters has been hampered by the lack of knowledge concerning the influence of operating conditions on mass transfer, hydromechanics, and power input. However, in recent years the properties of shake flasks have been described with empirical models. A practical scale-up strategy for everyday use is introduced for the scale-up of aerobic cultures from shake flasks to fermenters in batch and continuous mode. The strategy is based on empirical correlations of the volumetric mass transfer coefficient (kLa) and the pH. The accuracy of the empirical kLa correlations and the assumptions required to use these correlations for an arbitrary biological medium are discussed. To determine the optimal pH of the culture medium a simple laboratory method based on titration curves of the medium and a mechanistic pH model, which is solely based on the medium composition, is applied. The effectiveness of the scale-up strategy is demonstrated by comparing the behavior of Corynebacterium glutamicum on lactic acid in shake flasks and fermenters in batch and continuous mode. The maximum growth rate (µmax,=,0.32 h,1) and the oxygen substrate coefficient (,=,0.0174 mol/l) of C. glutamicum on lactic acid were equal for shake flask, fermenter, batch, and continuous cultures. The biomass substrate yield was independent of the scale, but was lower in batch cultures (YX/S,=,0.36 g/g) than in continuous cultures (YX/S,=,0.45 g/g). The experimental data (biomass, respiration, pH) could be described with a simple biological model combined with a mechanistic pH model. Biotechnol. Bioeng. 2007; 98: 800,811. © 2007 Wiley Periodicals, Inc. [source] Design of a Tubular Loop Bioreactor for Scale-up and Scale-down of Fermentation ProcessesBIOTECHNOLOGY PROGRESS, Issue 5 2003Maria Papagianni Microorganisms traveling through circulation loops in large-scale bioreactors experience variations in their environment such as dissolved oxygen concentration and pH gradients. The same changes are not experienced in small bioreactors, and it is suggested that herein lies one of the major reasons for the problems encountered when translating fermentation data from one scale to another. One approach to study this problem is to look at the circulation loop itself. The present work concerns an attempt to simulate the circulation loops inside stirred tank reactors, using a tubular loop reactor specially constructed for the purpose. The reactor carries a number of ports and probes along its length for the determination of concentration gradients within. The broth is circulated around the loop by the use of peristaltic pumps, and the circulation time (tc, s) is used as a measure of simulated reactor size. The reactor system has been evaluated using the citric acid fermentation by Aspergillus niger as a test process. Acid production and fungal morphology, in terms of the mean convex perimeter of mycelial clumps quantified by image analysis, were used as the parameters of evaluation for the two systems in comparison. From comparative experiments carried out in 10 and 200 L stirred tank bioreactors, it appears that the loop reactor simulates the corresponding stirred tank representing a valuable tool in scaling up and scaling down of fermentation process. [source] Photochemical Production of Vitamin D2, Scale-up and OptimizationCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 8 2007J. Lu No abstract is available for this article. [source] The J2EE ECperf benchmark results: transient trophies or technology treasures?CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 10 2004Paul Brebner Abstract ECperf, the widely recognized industry standard J2EE benchmark, has attracted a large number of results submissions and their subsequent publications. However, ECperf places little restriction on the hardware platforms, operating systems and databases utilized in the benchmarking process. This, combined with the existence of only two primary metrics, makes it difficult to accurately compare the performance of the Application Server products themselves. By mining the full-disclosure archives for trends and correlations, we have discovered that J2EE technology is very scalable both in a scale-up and scale-out manner. Other observed trends include a linear correlation between middle-tier total processing power and throughput, as well as between J2EE Application Server license costs and throughput. However, the results clearly indicate that there is an increasing cost per user with increasing capacity systems and scale-up is proportionately more expensive than scale-out. Finally, the correlation between middle-tier processing power and throughput, combined with results obtained from a different ,lighter-weight' benchmark, facilitates an estimate of throughput for different types of J2EE applications. Copyright © 2004 John Wiley & Sons, Ltd. [source] Crystallization for the Downstream Processing of ProteinsENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2005S. Schmidt Abstract Protein crystallization offers great potential in downstream processing of pharmaceutical protein active ingredients. The advantages, which are well known and widely utilized in low-molecular weight crystallization, can also be expected to be found to some extent in protein crystallization. However, there is still a marked need for improvement in two main areas of protein processing, namely, in crystallization from impure solutions and scale-up. [source] Performance of a World Health Organization first-line regimen (stavudine/lamivudine/nevirapine) in antiretroviral-naïve individuals in a Western settingHIV MEDICINE, Issue 5 2007LWY Tam Objectives In 2003, the World Health Organization (WHO) and Joint United Nations Programme on HIV/AIDS (UNAIDS) introduced the ,3 by 5 Initiative' to treat 3 million individuals by the end of 2005. This study evaluates the time to treatment termination, viral load suppression, and detection of drug resistance among antiretroviral-naïve individuals initiating stavudine/lamivudine/nevirapine (d4T/3TC/NVP) in British Columbia, Canada, to provide a context for future programme planning. Methods Primary outcome was time to treatment termination. Secondary outcome was time to viral suppression. Accumulation of drug resistance mutations was followed systematically in the first 145 individuals over 30 months. Cox proportional hazard regression identified factors associated with termination and suppression. Results 312 antiretroviral-naïve individuals initiated d4T/3TC/NVP between August 1996 and September 2003. Median follow-up time was 26.5 months (interquartile range [IQR] 6.8,46.5). At a median of 12.4 months (IQR 4.3,33.3), 132 (42.3%) patients switched treatment, 53 (17.0%) stopped therapy and 26 (8.3%) died. Of 308 subjects with baseline viral load >500 copies/mL, 223 (72.4%) suppressed to ,500 copies/mL at a median of 2.0 months. Among 145 (46.5%) individuals followed longitudinally, resistance mutations to NNRTI, 3TC, or other NRTI were detected in 11 (7.6%), six (4.1%) and four (2.8%) individuals after 12 months of therapy; and in 23 (15.9%), 17 (12.0%), and six (4.1%) individuals after 30 months. Conclusions The population requiring second-line treatment was 30% at 12 months and 40% at 24 months; 20% had detectable drug resistance mutations by 30 months. While these results are from a Western setting, they illustrate the need to consider second- and third-line approaches as antiretroviral treatment scale-up continues in the developing world. [source] Ruthenium-Catalyzed Alkyne Oxidation with Part-Per-Million Catalyst LoadingsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010Wei Ren Abstract Using a catalytic system of the (cymene)ruthenium dichloride dimer, [Ru(cymene)Cl2]2, (0.001,mol%) and iodine (10,mol%), a variety of alkynes bearing different functional groups were oxidized with tert -butyl hydroperoxide (TBHP; 70% solution in water) under mild conditions to give 1,2-diketones in good to excellent yields. Two noteworthy features of the method are the extremely high catalyst productivity (TON up to 420,000) and scale-up to 1,mol. Preliminary mechanism investigations showed that iodonium ion and water were involved in the transformation. [source] Promiscuous Substrate Binding Explains the Enzymatic Stereo- and Regiocontrolled Synthesis of Enantiopure Hydroxy Ketones and DiolsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Marcela Kurina-Sanz Abstract Regio- and stereoselective reductions of several diketones to afford enantiopure hydroxy ketones or diols were accomplished using isolated alcohol dehydrogenases (ADHs). Results could be rationalised taking into account different (promiscuous) substrate-binding modes in the active site of the enzyme. Furthermore, interesting natural cyclic diketones were also reduced with high regio- and stereoselectivity. Some of the 1,2- and 1,3-diketones used in this study were reduced by employing a low excess of the hydrogen donor (2-propanol) due to the quasi-irreversibility of these ADH-catalysed processes. Thus, using lower quantities of co-substrate, scale-up could be easily achieved. [source] Cyclic Enones as Substrates in the Morita,Baylis,Hillman Reaction: Surfactant Interactions, Scope and Scalability with an Emphasis on FormaldehydeADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2009Brett Abstract Traditionally, cyclic enones and formalin are reactants notorious for displaying problematic behaviour (i.e., poor solubility and low yields) under Morita,Baylis,Hillman (MBH) reaction conditions. The body of research presented herein focuses on the use of surfactants in water as a solvent medium that offers a resolution to many of the issues associated with the MBH reaction. Reaction scope, scalability and small angle X-ray scattering have been studied to assist with the understanding of the reaction mechanism and industrial application. A comparison against known literature methods for reaction scale-up is also discussed. [source] Cover Picture: Industrial-Scale Palladium-Catalyzed Coupling of Aryl Halides and Amines ,A Personal Account (Adv. Synth.ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2006Catal. Abstract The cover picture shows a typical vessel for industrial scale-up of chemical reactions, in this case for the synthesis of dialkylphosphinobiphenyl ligands. These ligands are important catalyst components for the amination of aryl halides. For more details, see the Review by Stephen L. Buchwald, Christelle Mauger, Gerard Mignani, and Ulrich Scholz on pages 23,,,39. [source] Assessing impacts of large herbivores on shrubs: tests of scaling factors for utilization rates from shoot-level measurementsJOURNAL OF APPLIED ECOLOGY, Issue 1 2007DANIELLE M. BILYEU Summary 1Accurate methods for estimating the intensity of browsing by herbivores are fundamental to understanding the ecology of shrub communities. Quantifying browse utilization on shrubs at large scales is difficult because shrubs have complex, spatially variable growth forms. Most existing methods estimate browsing rate at the scale of linear current-year shoots or twigs. How such fine-scale estimates relate to the proportion of current-year growth consumed from whole plants or plots is often unknown. The relationship is likely to be complex because herbivores selectively browse more productive plants and plant parts. 2Using a clipping experiment designed to mimic elk Cervus elaphus browsing, we quantified how utilization estimates at the scale of individual current-year shoots of two willow species, Salix bebbiana and Salix geyeriana, relate to actual mass removed at the scale of rooted stems. Three approaches to scaling were examined: (i) taking an average, (ii) multiplying by the proportion of shoots clipped and (iii) multiplying by a novel scaling factor that weights utilization by productivity. To address how to scale-up from stems to plots, we applied the most accurate stem-level method to elk-browsed willow and compared plot-level estimates by two scaling approaches. 3In scaling from shoots to stems, the novel scaling factor was most successful and resulted in accurate estimates for up to c. 45% of current annual growth clipped. In scaling from the stem to the plot, elk preference for more productive stems caused a simple average of stem-level utilization to differ from a productivity-weighted average by 15%. 4Synthesis and applications. In order to reflect accurately the proportion of biomass consumed at a whole-plant level, fine-scale estimates of utilization should be weighted by an estimate of pre-browse productivity, as this is mathematically equivalent to summing pre-browse and post-browse mass before calculating the proportion consumed. In developing methods to estimate utilization at plot scales, an important consideration is the choice of sampling unit, which should be both amenable to unbiased sampling and tractable in terms of measuring productivity. [source] Applied issues with predators and predation: editor's introductionJOURNAL OF APPLIED ECOLOGY, Issue 2 2002S. J. Ormerod Summary 1,The effects of predation are among the most pervasive in ecology. As parasitoids, parasites, grazers or top carnivores, predators have large influences on the distribution, density, dynamics and evolved traits of other organisms. Effects scale-up to influence community attributes such as species coexistence and ecosystems processes such as production or trophic cascades. 2,Increasingly, however, some of the largest predation issues fall clearly within the scope of applied ecology. They include instances where, due to their ecological attributes and trophic position: (i) predators are valuable to nature conservation, as biocontrol agents, as natural enemies, or as grazers used in rangeland or ecosystem management; (ii) natural or introduced predators are viewed negatively due to effects on conservation, agriculture, forestry, hunting or disease transmission; (iii) predators are affected by human activities such as resource exploitation, or from exposure to factors such as biomagnified pollutants and disturbance; (iv) predators are controversial because different groups view them as either desirable or undesirable. 3,In all these cases, ecologists have a pivotal rôle in facilitating appropriate management. For valued predators, this involves developing sufficient ecological understanding to optimize habitat, increase prey abundance or to reinforce, establish or reintroduce desirable species. For predators considered undesirable, management can involve direct control. In other cases, predation and its consequences can be mitigated by deterrent, exclusion, supplementary feeding, habitat management to favour prey, predator swamping, or by compensating losses financially. These latter strategies are often used where predators are themselves considered too valuable to remove or control. 4,This collection of seven papers illustrates many of these themes by examining contrasting aspects of the applied ecology of Eurasian lynx; by further probing the interaction between predatory birds and red grouse; by exploring the effects of weather on biocontrol; and by illustrating effects on plant species where grazing or seed predation play a dominant rôle. 5,A key lesson from these and other recent papers in the Journal of Applied Ecology is that the successful management of predators depends invariably on understanding adequately the exact ecological context in which predator,prey interactions take place and in which problems arise. With predator-related issues growing rather than diminishing, ecologists will need sufficient resources to maintain current research if they are to provide the understanding required to offer and evaluate sound management. [source] Bioprocess scale-up: quest for the parameters to be used as criterion to move from microreactors to lab-scaleJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2010Marco P. C. Marques Abstract Advances in high-throughput process development and optimization involve the rational use of miniaturized stirred bioreactors, instrumented shaken flasks and microtiter plates. As expected, each one provides different levels of control and monitoring, requiring a compromise between data quantity and quality. Despite recent advances, traditional shaken flasks with nominal volumes below 250 mL and microtiter plates are still widely used to assemble wide arrays of biotransformation/bioconversion data, because of their simplicity and low cost. These tools are key assets for faster process development and optimization, provided data are representative. Nonetheless, the design, development and implementation of bioprocesses can present variations depending on intrinsic characteristics of the overall process. For each particular process, an adequate and comprehensive approach has to be established, which includes pinpointing key issues required to ensure proper scale-up. Recently, focus has been given to engineering characterization of systems in terms of mass transfer and hydrodynamics (through gaining insight into parameters such as kLa and P/V at shaken and microreactor scale), due to the widespread use of small-scale reactors in the early developmental stages of bioconversion/biotransfomation processes. Within this review, engineering parameters used as criteria for scaling-up fermentation/bioconversion processes are discussed. Particular focus is on the feasibility of the application of such parameters to small-scale devices and concomitant use for scale-up. Illustrative case studies are presented. Copyright © 2010 Society of Chemical Industry [source] Improvements in the production of bacterial synthesized biocellulose nanofibres using different culture methodsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2010Amir Sani Abstract This review summarizes previous work that was done to improve the production of bacterial cellulose nanofibres. Production of biocellulose nanofibres is a subject of interest owing to the wide range of unique properties that makes this product an attractive material for many applications. Bacterial cellulose is a natural nanomaterial that has a native dimension of less than 50 nm in diameter. It is produced in the form of nanofibres, yielding a very pure cellulose product with unique physical properties that distinguish it from plant-derived cellulose. Its high surface-to-volume ratio combined with its unique properties such as poly-functionality, hydrophilicity and biocompatibility makes it a potential material for applications in the biomedical field. The purpose of this review is to summarize the methods that might help in delivering microbial cellulose to the market at a competitive cost. Different feedstocks in addition to different bioreactor systems that have been previously used are reviewed. The main challenge that exists is the low yield of the cellulosic nanofibres, which can be produced in static and agitated cultures. The static culture method has been used for many years. However, the production cost of this nanomaterial in bioreactor systems is less expensive than the static culture method. Biosynthesis in bioreactors will also be less labour intensive when scaled up. This would improve developing intermediate fermentation scale-up so that the conversion to an efficient large-scale fermentation technology will be an easy task. Copyright © 2009 Society of Chemical Industry [source] Kinetic study of the manganese-based catalytic hydrogen peroxide oxidation of a persistent azo-dyeJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2010Chedly Tizaoui Abstract BACKGROUND: The discharge of synthetic dyes by the textile industry into the environment poses concerns due to their persistence and toxicity. New efficient treatment processes are required to effectively degrade these dyes. The aim of this work was to study the degradation of a persistent dye (Drimarene Brilliant Reactive Red K-4BL, C.I.147) using H2O2 oxidation catalysed by an Mn(III)-saltren catalyst and to develop a kinetic model for this system. RESULTS: Dye oxidation with H2O2 was significantly improved by the addition of the catalyst. As the pH was increased from 3 to 10, the oxidation rates increased significantly. The kinetic model developed in this study was found to adequately explain the experimental results. In particular, dye oxidation can be described at high pH by pseudo-first-order kinetics. A Michaelis,Menton type equation was developed from the model and was found to adequately describe the effect of H2O2 and catalyst concentrations on the apparent pseudo-first-order rate constant. Optimum catalyst and H2O2 concentrations of 500 mg L,1 and 6.3 g L,1, respectively, were found to give maximum reaction rates. CONCLUSION: Catalytic H2O2 oxidation was found to be effective for the removal of persistent dye and the results obtained in this work are of significance for design and scale-up of a treatment process. Copyright © 2009 Society of Chemical Industry [source] An overview of the mathematical modelling of liquid membrane separation processes in hollow fibre contactorsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 11 2009E Bringas Abstract Liquid membranes have traditionally been employed for liquid/liquid mass transfer and have found applications in industrial, biomedical and analytical fields as well as in hydrometallurgical processes, wastewater treatment and remediation of polluted groundwater. However, in spite of the known advantages of liquid membranes, there are few examples of industrial application. The development of reliable mathematical models and design parameters (mass transport coefficients and equilibrium or kinetic parameters associated with the interfacial reactions) is a necessary step for design, cost estimation, process optimisation and scale-up. This work reports an overview of the different approaches that have been proposed in the literature to the mathematical modelling of liquid membrane separation processes in hollow fibre contactors providing, at the same time, a useful guideline to characterise the mass transport phenomena and a tool for the optimal design and intensification of separation processes. Copyright © 2009 Society of Chemical Industry [source] Application of Cavitational reactors for cell disruption for recovery of intracellular enzymesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2008Parag R. Gogate Abstract Cavitational reactors are a novel and promising form of multiphase reactors, based on the principle of release of a large amount of energy owing to the violent collapse of cavities. This paper presents an overview of cavitational reactors in the specific area of cell disruption for the recovery of intracellular enzymes, in terms of the basic aspects, different reactor configurations including recommendations for optimum operating parameters and review of earlier literature reports. It has been observed that under optimized conditions, cavitational reactors can reduce the energy requirement for the release of intracellular enzymes by an order of magnitude compared with conventional cell disruption techniques used on an industrial scale. However, problems associated with efficient scale-up and operation at conditions required for industrial scale, hamper the successful utilization of cavitational reactors at this time. Some recommendations have been made for the future work required to realize the dream of harnessing the spectacular effects of cavitation phenomena. Copyright © 2008 Society of Chemical Industry [source] Advanced oxidation processes for water treatment: advances and trends for R&DJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2008Christos Comninellis Abstract Advanced oxidation comprises a range of similar but different chemical processes aimed at tackling pollution in water, air and soil. Over the past few decades, multidisciplinary research has been carried out to study a broad spectrum of topics such as understanding of process fundamentals, elucidation of kinetics and mechanisms, development of new materials, modelling, process integration and scale-up. This article identifies and discusses certain directions that seem to advance R&D on advanced oxidation for water/wastewater treatment. Copyright © 2008 Society of Chemical Industry [source] Electrolytic removal of ammonia from brine wastewater: scale-up, operation and pilot-scale evaluationJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2004Catalino G Alfafara Abstract Brine wastewater with a high ammonia content from an iodine processing plant (commonly called kansui in Japan) was treated by electrolysis. The system, which can be considered as an indirect electrolytic treatment process, generates chlorine at the anodes and initiates the formation of mixed oxidants like hypochlorous acid. The oxidants then act as agents for ammonia destruction. Laboratory-scale experiments showed that high ammonia concentrations (as much as 200 mg dm,3) could be completely removed within a few minutes, and could be considered a good alternative for efficient ammonia removal from saline wastewaters. From laboratory-scale experiments in the batch and continuous modes, the charge dose was analyzed and used as the operating and scale-up factor. The value of the charge dose was not severely affected by changes in operating conditions such as electrode spacing and temperature. The charge dose from batch and continuous runs was found to be in the range of 23 C (mg NH4 -N removed),1 to 29 C (mg NH4 -N removed),1. Using the charge dose obtained from laboratory-scale continuous electrolysis experiments as the scale-up factor, a pilot-scale reactor was designed, and the operating conditions were calculated. In the pilot-scale reactor tests at different flow rates, the effluent ammonia concentrations were reasonably close to the calculated values predicted from the charge dose equation. Copyright © 2004 Society of Chemical Industry [source] Operating and scale-up factors for the electrolytic removal of algae from eutrophied lakewaterJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2002Catalino G Alfafara Abstract Electrolytic removal of algae was conducted in batch and continuous reactors to investigate operating factors affecting removal efficiency and to explore engineering relationships which could be useful for operation and scale-up. The system integrated both electro-flocculation and electro-flotation mechanisms by using polyvalent metal anodes and inert metal cathodes. Batch reactor studies confirmed that high electrical input power or higher electrical current achieved higher and faster removal efficiencies. Natural liquid circulation was observed during electrolytic operation and increased with higher electrical power. However, a small degree of external mixing may be useful at lower electrical power input. Electro-flotation alone could not achieve complete algae removal (maximum efficiency 40,50%), and showed the importance of algal floc formation for the complete removal of algae. In continuous electrolysis experiments, the ratio of the volumetric current intensity (amperes,dm,3) and the chlorophyll a loading (mg,dm,3,h,1) was found to be a useful operating and scale-up factor to balance high algal removal efficiency with minimum release of excess aluminum. This ratio was eventually found to be just the charge dose or the amount of coulombs required to remove a unit mass of chlorophyll a. The optimum charge dose was determined and used to relate the operating current and electrolysis time of a continuous process. © 2002 Society of Chemical Industry [source] Catalytic wet air oxidation of phenol using active carbon: performance of discontinuous and continuous reactorsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2001Frank Stüber Abstract Catalytic wet air oxidation (CWAO) of an aqueous phenol solution using active carbon (AC) as catalytic material was compared for a slurry and trickle bed reactor. Semi-batchwise experiments were carried out in a slurry reactor in the absence of external and internal mass transfer. Trickle-bed runs were conducted under the same conditions of temperature and pressure. Experimental results from the slurry reactor study showed that the phenol removal rate significantly increased with temperature and phenol concentration, whereas partial oxygen pressure had little effect. Thus, at conditions of 160,°C and 0.71,MPa of oxygen partial pressure, almost complete phenol elimination was achieved within 2,h for an initial phenol concentration of 2.5,g,dm,3. Under the same conditions of temperature and pressure, the slurry reactor performed at much higher initial rates with respect to phenol removal than the trickle bed reactor, both for a fresh active carbon and an aged active carbon, previously used for 50,h in the trickle bed reactor, but mineralisation was found to be much lower in the slurry reactor. Mass transfer limitations, ineffective catalyst wetting or preferential flow in the trickle bed alone cannot explain the drastic difference in the phenol removal rate. It is likely that the slurry system also greatly favours the formation of condensation polymers followed by their irreversible adsorption onto the AC surface, thereby progressively preventing the phenol molecules to be oxidised. Thus, the application of this type of reactor in CWAO has to be seriously questioned when aiming at complete mineralisation of phenol. Furthermore, any kinetic study of phenol oxidation conducted in a batch slurry reactor may not be useful for the design and scale-up of a continuous trickle bed reactor. © 2001 Society of Chemical Industry [source] APPLICATION OF DISCRETE MODELING APPROACH TO FLUIDIZED BED YEAST DRYINGJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2010F. DEBASTE ABSTRACT Yeast drying is widely used to ease transport and conservation. In this work, baker's yeast drying in fluidized bed is modeled using a pore network model. Classical balanced equations at the reactor scale are coupled with the pore network for the grain, which takes into account diffusion in the gas phase, transport by liquid film in partially saturated region and pressure gradient effects in the liquid phase. The porous structure to be applied in the model is obtained using environmental scanning electron microscopy. Simulations are validated on a thermogravimetric analysis experiment. The model is then applied to fluidized bed drying for which experimental results obtained on a laboratory pilot are available. Finally, the model results are compared to those of a simplified receding front model. PRACTICAL APPLICATIONS The presented model allows simulation of Saccharomyces cerevisiae fluidized bed drying. Taking into account transport phenomena in the grain offers the opportunity to predict drying rate without the use of a desorption isotherm. Moreover, the model predicts roughly the critical humidity. Therefore, the model can be used for scale-up, design and optimization of dryer including the effect of changes in yeast granulation. [source] | ||||||||||||||||||||||||||||||||||||||||