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Menka Petkovska - One of the best experts on this subject based on the ideXlab platform.
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periodic operation with modulation of Inlet Concentration and flow rate part ii adiabatic continuous stirred tank reactor
Chemical Engineering & Technology, 2016Co-Authors: Daliborka Nikolic, Matthias Felischak, Andreas Seidelmorgenstern, Menka PetkovskaAbstract:The nonlinear frequency response (NFR) method, which is an analytical, fast, and easy method for evaluating the performance of forced periodically operated chemical reactors, was used to investigate possible improvements to a nonisothermal continuous stirred-tank reactor (CSTR) when Inlet Concentration and/or flow rate are periodically modulated. The product yield was used for evaluating the performance improvements. Part I of this paper considered the general nonisothermal case. In this part, the results are applied to an adiabatic CSTR. A laboratory-scale adiabatic CSTR was analyzed by applying kinetic parameters for the hydrolysis of acetic anhydride. It is shown that improvement can be obtained for simultaneous modulation of the two inputs with appropriately chosen forcing parameters.
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nonlinear frequency response analysis of forced periodic operation of non isothermal cstr using single input modulations part i modulation of Inlet Concentration or flow rate
Chemical Engineering Science, 2014Co-Authors: Daliborka Nikolic, Andreas Seidelmorgenstern, Menka PetkovskaAbstract:Periodic operation of a non-isothermal CSTR subject to a single input modulation is analyzed considering a nth order reaction and using the nonlinear frequency response (NFR) method, introduced in our previous publications. The method is based on deriving the asymmetrical second order frequency response function (FRF) and analyzing its sign. In Part I of this paper, the periodic modulations of Inlet Concentration or flow-rate of the reaction stream were investigated. In this Part II, periodic operations are analyzed for modulations of the temperature of the Inlet reaction stream or the temperature of the heating/cooling fluid. Conditions that need to be fulfilled in order to achieve process improvement through periodic operation are identified. The method is applied for the same numerical example taken from literature which was used in Part I. The results obtained by the NFR method are compared with the results of numerical simulations. Good agreement is obtained, except for forcing frequencies close to the resonant frequency. In these cases, even the sign of the DC component was not predicted correctly.
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Evaluation of periodic processes with two modulated inputs based on nonlinear frequency response analysis. Case study: CSTR with modulation of the Inlet Concentration and flow-rate
Chemical Engineering Science, 2013Co-Authors: Daliborka Nikolic Paunic, Menka PetkovskaAbstract:Abstract In our previous work, a new, fast and easy, nonlinear frequency response method for analysing potential improvements of reactor performance by forced periodic operation was presented. This method, which is based on Volterra series, generalized Fourier transform and the concept of higher-order frequency response functions (FRFs), gives an approximate value of the average process performance directly, without numerical simulation of the complete process. It was shown that the asymmetrical second order frequency response function, ( G 2 ( ω , − ω ) ) corresponds to the dominant term of the non-periodic (DC) component of the periodic steady-state response and determines the average performance of the periodic process. Thus, in order to evaluate the potential of a periodic reactor operation, it is enough to derive and analyse this function. In this work this method is extended to evaluating periodic operations with forced oscillations of two modulated inputs. In this case the nonlinear system has to be defined by three sets of frequency response functions, two of them correlating the output to each of the inputs and one set of cross-FRFs. The general methodology for this case is developed. It is further used to analyse the time-average performance of an isothermal continuous stirred tank reactor (CSTR) with forced periodic modulation of the Inlet Concentration and flow-rate, for a simple n th order homogeneous reaction. The analysis is performed for cases when the Inlet Concentration and flow-rate are modulated simultaneously. The optimal choice of the phase shift between the two inputs is discussed in detail.
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Determination of competitive adsorption isotherms applying the nonlinear frequency response method. Part I. Theoretical analysis.
Journal of chromatography. A, 2009Co-Authors: Milica Ilić, Menka Petkovska, Andreas Seidel-morgensternAbstract:In this work adsorption equilibria of binary mixtures are quantified analyzing the nonlinear frequency response of a chromatographic column. Local partial derivatives of an isotherm model can be estimated for certain steady-states from the low frequency asymptotes of the corresponding frequency response functions (FRFs). The required FRFs correspond to two different compounds and the type of the imposed Inlet Concentration changes, e.g. periodical Inlet Concentration changes of only one compound or of both of them. For an accurate determination of isotherm parameters, it is necessary to approach as close as possible the low frequency asymptotic behaviour of these functions. Based on principles valid for the FRFs corresponding to the adsorption of a single solute, frequencies needed to reach the low frequency asymptotes of the functions of interest for estimating competitive isotherms are defined in this paper. The relation between the accuracy of the isotherm parameters determined and numbers and types of periodical Inlet Concentration changes and steady-states analyzed is also evaluated.
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Analysis and experimental demonstration of forced periodic operation of an adiabatic stirred tank reactor: Simultaneous modulation of Inlet Concentration and total flow-rate
Chemical Engineering Journal, 1Co-Authors: Matthias Felischak, Menka Petkovska, Daliborka Nikolic, Lothar Kaps, Christof Hamel, Andreas Seidel-morgensternAbstract:Abstract It is well known, that forced periodic operation possesses the potential for process improvements. Nevertheless, only a small number of applications is reported, due to complex realization, limited predictability and high inertia of larger units. Nonlinear frequency response (NFR) analysis has proven to predict efficiently time-averaged performance of reactor effluent streams originating from forced periodic changes of one or several input(s). Focus of this paper was an experimental demonstration of forced periodic operation applied to the hydrolysis of acetic anhydride carried out in an adiabatic CSTR. Theoretical results provided a guideline for experiments exploiting simultaneous sinusoidal modulations of the anhydride Inlet Concentration and the total volumetric flow-rate. Influences of the forcing parameters (amplitudes and the phase difference) were also studied. Confirming the predictions of NFR analysis a significantly higher time-averaged product yields were experimentally achieved compared to conventional steady-state operation with simultaneous modulation of two inputs using an optimized phase shift.
Michele Heitz - One of the best experts on this subject based on the ideXlab platform.
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Analysis and comparison of biotreatment of air polluted with ethanol using biofiltration and biotrickling filtration.
Environmental technology, 2011Co-Authors: Karine Morotti, Antonio Avalos Ramirez, J Peter Jones, Michele HeitzAbstract:This study analyses the performance of ethanol biofiltration with percolation (biotrickling filtration, BTF) comparing to a conventional biofilter (biofiltration, BF). Two biofilters packed with clay balls were operated in a range of Inlet Concentrations of ethanol in the air varying from 0.47 to 2.36 g m(-3). For both the BF and BTF, the specific growth rate (mu) and the elimination capacity (EC) decreased with the ethanol Inlet Concentration, presenting a kinetic of substrate inhibition. A Haldane-type model was adjusted for both biofilters in order to model both EC and mu as a function of the ethanol Inlet Concentration in the gas. The maximum EC was similar for both biofilters, at around 46 g m(-3) h(-1), whereas the maximum mu was 0.0057 h(-1) for the BF and 0.0103 h(-1) for the BTF. The maximum of ethanol removed, occurred at the lowest Inlet Concentration of (0.47 gm(-3)), and reached 86% for the BF and 74% for the BTF.
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Biotrickling filtration of air contaminated with ethanol
Journal of Chemical Technology & Biotechnology, 2007Co-Authors: Antonio Avalos Ramirez, J Peter Jones, Michele HeitzAbstract:A biotrickling filter (BTF) for treating high ethanol loads was operated for one year and the effect of operating conditions was studied. The BTF was operated in a range of ethanol Inlet Concentrations of 0.2–15.0 g m−3 and at three different residence times (30, 65 and 130 s). The experiments show that removal efficiency decreased with increasing ethanol Inlet Concentration and decreasing air residence time. Removal efficiency varied in the range of 60–100%. A maximum elimination capacity of 970 g m−3 h−1 was obtained for an Inlet load of 1610 g m−3 h−1. At a constant residence time, the carbon dioxide (CO2) production rate varied with ethanol Inlet Concentration. BTF presented the maximum CO2 production rate in the range of Inlet Concentration of 3.0–7.0 g m−3. Two strategies for controlling biomass accumulation were applied: one consisted in periodical washing; the other combined periodical washing with nutrient starvation by consuming less water and energy. Both strategies led to maintaining the BTF stable, with high adaptability and reproducibility. Copyright © 2007 Society of Chemical Industry
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Methanol and ethanol treatment by biotrickling filtration: an experimental study
2005Co-Authors: Antonio Avalos Ramirez, J.p. Jones, Michele HeitzAbstract:The paper is related to the development of a high performance BTF to control methanol and ethanol emissions. Removal efficiency was studied in terms of various operational parameters such as Inlet Concentration of alcohol and empty bed residence time (EBRT). For an EBRT of 65 s, removal efficiency attained 75% in a range of ethanol Inlet Concentration of 1200 to 8000 ppmv, and in a range of methanol Inlet Concentration of 400 to 6500 ppmv. These results show that BTF removal efficiency was not affected by VOC Concentration at constant EBRT. On the other hand, the EBRT has a direct effect on removal efficiency. When BTF operated at an ethanol Inlet Concentration of 400 ppmv the removal efficiency was nearly 100 % for an EBRT in the range of 65 s to 130 s, and it was 75 % for an EBRT of 30 s. Carbon dioxide generation was also analyzed and correlated with BTF performance.
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biofiltration of xylene emissions bioreactor response to variations in the pollutant Inlet Concentration and gas flow rate
Chemical Engineering Journal, 2004Co-Authors: Hicham Elmrini, Nathalie Bredin, Zarook Shareefdeen, Michele HeitzAbstract:Abstract In order to remove xylene vapors from an air stream, an upflow laboratory scale biofilter was operated for a period of 2 months. The experimental study consisted of two different phases: in the first phase, the biofilter was operated at various gas flow rates and the xylene Inlet Concentration was maintained at 1.39 g m −3 . In the second phase, various Inlet Concentrations of the contaminant were tested at a constant gas flow rate of 0.4 m 3 h −1 corresponding to an empty bed residence time of 150 s. The biofilter response to steep and abrupt variations in the xylene Inlet Concentration and gas flow rate was examined. The results obtained revealed that the removal efficiency of the biofilter regained its high values (above 96%) in less than 24 h following the change to low Concentrations and gas flow rate. Temperature measurements showed that the biofilter temperature strongly depends on the intensity of the microbial activity in the filter bed. The experimental mass ratio of carbon dioxide produced to the xylene removed was equal to 2.72 indicating that the contaminant was eliminated exclusively by aerobic biodegradation. These findings suggest that a follow up of the amount of carbon dioxide produced in the filter bed can be very helpful in monitoring the performance of the biofilter. For relatively small Inlet loads of xylene, the contributions of the different sections of the biofilter to the removal efficiency of the contaminant and the carbon dioxide production were unevenly balanced but became more uniformly distributed for relatively high Inlet loads.
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Elimination of chlorobenzene vapors from air in a compost-based biofilter
Journal of Chemical Technology & Biotechnology, 2003Co-Authors: Marie-caroline Delhoménie, Michele HeitzAbstract:In this work, the removal of monochlorobenzene (CB) vapors from air was studied, for the first time, in a non-inoculated, laboratory-scale, aerobic biofilter. The influence of three parameters on the bioprocess has been evaluated: the rate of nitrogen supplied to the bed, the Inlet Concentration of CB, and the flow rate. The CB Inlet Concentration was varied between 0.3 and 3.2 g m−3, at a constant flow rate of 1.0 m3 h−1. Removal rates of greater than 90% were achieved for CB Inlet Concentrations of up to 1.2 g m−3. Then the flow rate was varied from 0.5 to 3.0 m3 h−1 with a constant Inlet Concentration (1.2 g m−3). Maximum elimination capacities (70 g m−3 h−1) were reached for contact times of greater than 60 s. The study of varying flow rates also permitted evaluation of a first order macrokinetic constant (1.1 × 10−2 s−1) for the CB biodegradation. Finally, the optimum nitrogen input value was found to lie between 0.3 and 0.4 g N h−1 and gave rise to elimination capacities as high as 70 g m−3 h−1 for an Inlet load of near 80 g m−3 h−1. Copyright © 2003 Society of Chemical Industry
J. M. Bisang - One of the best experts on this subject based on the ideXlab platform.
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Dynamic behaviour of electrochemical reactors for a step change in Inlet Concentration under potentiostatic control according to the dispersion model
Journal of Applied Electrochemistry, 2008Co-Authors: J. M. BisangAbstract:The dynamic modelling of electrochemical reactors under potentiostatic control is performed according to the dispersion model. The response of the system in Concentration and current is discussed for a step change in the Inlet Concentration in terms of the Peclet number. The stirred tank and plug flow behaviours are analyzed as limiting cases of the dispersion model.
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Dynamic behaviour of electrochemical reactors for a step change in the Inlet Concentration under galvanostatic or potentiostatic control
Journal of Applied Electrochemistry, 1998Co-Authors: J. M. BisangAbstract:The dynamic modelling of a cascade of continuous stirred tank electrochemical reactors under galvanostatic and potentiostatic control is performed. The response of the system in outlet Concentration and current (potentiostatic case) for a step change in the Inlet Concentration in terms of the number of reactors is analysed. The idealised models, stirred tank and plug flow, are also included as limiting cases. The time required to reach approximate steady-state values in terms of the number of reactors and electrochemical parameters is discussed.
Wu-chung Chan - One of the best experts on this subject based on the ideXlab platform.
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The influence of nonionic surfactant Brij 30 on biodegradation of toluene in a biofilter
African Journal of Biotechnology, 2010Co-Authors: Wu-chung Chan, Hong-yuan YouAbstract:-1 . Zero-order kinetics with diffusion limitation was regarded as the most adequate biochemical reaction kinetic model. The microbial growth rate and biochemical reaction rate were inhibited at higher surfactant content and toluene Inlet Concentration. The degree of inhibitive effect was more pronounced at lower toluene Inlet Concentration. The maximum elimination capacity decreased with increasing surfactant content. The addition of nonionic surfactant Brij 30 into filter material was unfavorable for toluene degraded by the microbial.
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Compounds interaction on the biodegradation of butanol mixture in a biofilter.
Bioresource technology, 2010Co-Authors: Wu-chung Chan, Yuan-sheng LinAbstract:Compounds interaction on the biodegradation of n-butanol and sec-butanol mixture in a composite bead biofilter was investigated. The biodegradation rate of compounds in the exponential growth phase and stationary phase for the single compound and two compounds mixing systems was determined. The microbial growth rate and biochemical reaction rate of two compounds decreased with increasing compound Inlet Concentration for the single compound system. The microbial metabolic activity of sec-butanol biodegraded in the microbial growth process and biochemical reaction process was inhibited as n-butanol was introduced. This inhibitive effect was more pronounced at higher n-butanol Inlet Concentration and lower sec-butanol Inlet Concentration for the two compounds mixing system.
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Compounds interaction on the biodegradation of acetone and methyl ethyl ketone mixture in a composite bead biofilter.
Bioresource technology, 2009Co-Authors: Wu-chung Chan, Tzu-yu LaiAbstract:Compounds interaction on the biodegradation of acetone and methyl ethyl ketone (MEK) mixture in a composite bead biofilter was investigated. The biodegradation rate of two compounds in the exponential growth phase and stationary phase for the single compound and two compounds mixing systems was determined. The microbial growth rate and biochemical reaction rate of biodegraded two compounds was inhibited at higher compound Inlet Concentration for the single compound system. The microbial metabolic activity of biodegraded acetone in the microbial growth process and biochemical reaction process was inhibited by introducing MEK and was more pronounced at higher MEK Inlet Concentration and lower acetone Inlet Concentration for the two compounds mixing system. The maximum elimination capacity of acetone and MEK for the single compound system was smaller and greater than those for the two compounds mixing system, respectively.
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Nonionic surfactant Brij35 effects on toluene biodegradation in a composite bead biofilter
African Journal of Biotechnology, 2009Co-Authors: Wu-chung Chan, Hui-zheng YouAbstract:Nonionic surfactant effects on the toluene dissolved in the water phase and biodegradation kinetic behaviors of toluene in a composite bead biofilter were investigated. The toluene dissolved in the water phase was enhanced by the addition of surfactant into aqueous solution and the enhancing effect was more pronounced in the surfactant Concentration less than critical micelle Concentration. For the microbial growth process, the microbial growth rate was inhibited at higher surfactant content and the degree of inhibitive effect was more pronounced at lower Inlet Concentration. The microbial growth rate was inhibited at higher Inlet Concentration. Zero-order kinetic with the diffusion limitation could be regarded as the most adequate biochemical reaction model. For the biochemical reaction process, the biochemical reaction rate was also inhibited at higher surfactant content and the degree of inhibitive effect was more pronounced at lower Inlet Concentration. The biochemical reaction rate was also inhibited at higher Inlet Concentration. The maximum elimination capacity decreased with increasing surfactant content and it was in the range of 17.41 to 26.12 g C h-1 m-3 bed volume. The addition of surfactant into filter material was unfavorable for toluene degraded by the microbial.
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Biodegradation kinetic behaviors of n-butyl alcohol and sec-butyl alcohol in a composite bead biofilter
Process Biochemistry, 2009Co-Authors: Wu-chung Chan, Yu-zhang LaiAbstract:Abstract Biodegradation kinetic behaviors of n-butyl alcohol and sec-butyl alcohol in a composite bead biofilter were investigated. The microbial growth rate of n-butyl alcohol was greater than that of sec-butyl alcohol in the Inlet Concentration range of 50–300 ppm. The microbial growth rate was inhibited at higher Inlet Concentration, and the inhibitive effect in the Concentration range of 50–150 ppm was more pronounced than that in the Concentration range of 150–300 ppm. The degree of inhibitive effect for n-butyl alcohol was more sensitive than that for sec-butyl alcohol in the Concentration range of 50–150 ppm. The zero-order kinetic with the diffusion rate limitation could be regarded as the most adequate biochemical reaction model. For the biochemical reaction process, the biochemical reaction rate coefficient of n-butyl alcohol was greater than that of sec-butyl alcohol in the Inlet Concentration range of 50–300 ppm. The biochemical reaction rate coefficient was decreased with increasing Inlet Concentration. The inhibitive effect for sec-butyl alcohol was more pronounced than that for n-butyl alcohol. The factor of the chemical structure of compound was more predominant in the microbial growth and biochemical reaction processes. The maximum elimination capacity of n-butyl alcohol and sec-butyl alcohol were 55.7 and 20.9 g C h−1 m−3 bed volume, respectively. The primary alcohol was easily biodegraded by the microbial.
Daliborka Nikolic - One of the best experts on this subject based on the ideXlab platform.
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periodic operation with modulation of Inlet Concentration and flow rate part ii adiabatic continuous stirred tank reactor
Chemical Engineering & Technology, 2016Co-Authors: Daliborka Nikolic, Matthias Felischak, Andreas Seidelmorgenstern, Menka PetkovskaAbstract:The nonlinear frequency response (NFR) method, which is an analytical, fast, and easy method for evaluating the performance of forced periodically operated chemical reactors, was used to investigate possible improvements to a nonisothermal continuous stirred-tank reactor (CSTR) when Inlet Concentration and/or flow rate are periodically modulated. The product yield was used for evaluating the performance improvements. Part I of this paper considered the general nonisothermal case. In this part, the results are applied to an adiabatic CSTR. A laboratory-scale adiabatic CSTR was analyzed by applying kinetic parameters for the hydrolysis of acetic anhydride. It is shown that improvement can be obtained for simultaneous modulation of the two inputs with appropriately chosen forcing parameters.
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nonlinear frequency response analysis of forced periodic operation of non isothermal cstr using single input modulations part i modulation of Inlet Concentration or flow rate
Chemical Engineering Science, 2014Co-Authors: Daliborka Nikolic, Andreas Seidelmorgenstern, Menka PetkovskaAbstract:Periodic operation of a non-isothermal CSTR subject to a single input modulation is analyzed considering a nth order reaction and using the nonlinear frequency response (NFR) method, introduced in our previous publications. The method is based on deriving the asymmetrical second order frequency response function (FRF) and analyzing its sign. In Part I of this paper, the periodic modulations of Inlet Concentration or flow-rate of the reaction stream were investigated. In this Part II, periodic operations are analyzed for modulations of the temperature of the Inlet reaction stream or the temperature of the heating/cooling fluid. Conditions that need to be fulfilled in order to achieve process improvement through periodic operation are identified. The method is applied for the same numerical example taken from literature which was used in Part I. The results obtained by the NFR method are compared with the results of numerical simulations. Good agreement is obtained, except for forcing frequencies close to the resonant frequency. In these cases, even the sign of the DC component was not predicted correctly.
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Analysis and experimental demonstration of forced periodic operation of an adiabatic stirred tank reactor: Simultaneous modulation of Inlet Concentration and total flow-rate
Chemical Engineering Journal, 1Co-Authors: Matthias Felischak, Menka Petkovska, Daliborka Nikolic, Lothar Kaps, Christof Hamel, Andreas Seidel-morgensternAbstract:Abstract It is well known, that forced periodic operation possesses the potential for process improvements. Nevertheless, only a small number of applications is reported, due to complex realization, limited predictability and high inertia of larger units. Nonlinear frequency response (NFR) analysis has proven to predict efficiently time-averaged performance of reactor effluent streams originating from forced periodic changes of one or several input(s). Focus of this paper was an experimental demonstration of forced periodic operation applied to the hydrolysis of acetic anhydride carried out in an adiabatic CSTR. Theoretical results provided a guideline for experiments exploiting simultaneous sinusoidal modulations of the anhydride Inlet Concentration and the total volumetric flow-rate. Influences of the forcing parameters (amplitudes and the phase difference) were also studied. Confirming the predictions of NFR analysis a significantly higher time-averaged product yields were experimentally achieved compared to conventional steady-state operation with simultaneous modulation of two inputs using an optimized phase shift.