Transport Phenomena,
T. Zarei; J. Khorshidi
Volume 14, Issue 1 , March 2017, , Pages 40-51
Abstract
This paper addresses an experimental investigation in the hydrodynamic behavior of a modified slotted sieve tray. Slotted sieve tray (Push valve sieve tray) is a sieve tray that the push valves have been utilized on the tray deck to eliminate liquid gradients and non-uniformity of liquid distribution ...
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This paper addresses an experimental investigation in the hydrodynamic behavior of a modified slotted sieve tray. Slotted sieve tray (Push valve sieve tray) is a sieve tray that the push valves have been utilized on the tray deck to eliminate liquid gradients and non-uniformity of liquid distribution on the tray. The air-water system was used in an industrial scale experimental rig with an internal diameter of 1.2 m. The dry pressure drop, total pressure drop, weeping and entrainment of the modified slotted sieve tray were measured and compared with the conventional sieve tray. Weeping and pressure drop data for the tray was correlated. Results show the better hydrodynamic behavior of the modified push valve sieve tray than a conventional sieve tray. This modification can be an effective and inexpensive way to debottleneck sieve tray columns, because it has good characteristic of sieve tray and eliminate the disadvantage of sieve tray by increasing the operating window of the tray.
Modeling and Simulation
mohsen pirdashti; kamyar movagharnejad; silvia Curteanu; Florin Leon; Farshad Rahimpour
Volume 13, Issue 4 , November 2016, , Pages 14-32
Abstract
Guanidine hydrochloride has been widely used in the initial recovery steps of active protein from the inclusion bodies in aqueous two-phase system (ATPS). The knowledge of the guanidine hydrochloride effects on the liquid-liquid equilibrium (LLE) phase diagram behavior is still inadequate and no comprehensive ...
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Guanidine hydrochloride has been widely used in the initial recovery steps of active protein from the inclusion bodies in aqueous two-phase system (ATPS). The knowledge of the guanidine hydrochloride effects on the liquid-liquid equilibrium (LLE) phase diagram behavior is still inadequate and no comprehensive theory exists for the prediction of the experimental trends. Therefore the effect the guanidine hydrochloride on the phase behavior of PEG4000+ potassium phosphate+ water system at different guanidine hydrochloride concentrations and pH was investigated in this study. To fill the theoretical gaps, the typical of support vector machines was applied to the k-nearest neighbor method in order to develop a regression model to predict the LLE equilibrium of guanidine hydrochloride in the above mentioned system. Its advantage is its simplicity and good performance, with the disadvantage of an increase the execution time. The results of our method are quite promising: they were clearly better than those obtained by well-established methods such as Support Vector Machines, k-Nearest Neighbour and Random Forest. It is shown that the obtained results are more adequate than those provided by other common machine learning algorithms.
Process Control and Engineering, Process Safety, HSE
Rahbar Rahimi; Shirin Boulaqhi; Amir Ziarifar
Volume 13, Issue 4 , November 2016, , Pages 33-45
Abstract
Simulation of a process and analysis of its resulting data in both dynamic and steady-state conditions are fundamental steps in understanding the process in order to design and efficient control of system as well as implementing operational cost reduction scheme. In the present paper, steady and unsteady ...
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Simulation of a process and analysis of its resulting data in both dynamic and steady-state conditions are fundamental steps in understanding the process in order to design and efficient control of system as well as implementing operational cost reduction scheme. In the present paper, steady and unsteady state simulation of Amir Kabir1, 3 butadiene purification units has been done by using Aspen and Aspen Dynamic software together with the Peng- Robinson equation of state to investigate the system responses to the disturbances. In the unsteady state simulation mode; the flow rates, pressure, temperature and level (FPTL) were controlled by Proportional-Integral-Derivative (PID) controllers in the unit. Finally, transient responses to changes such as feed temperature, feed flow rates, steam flow rates and the duties of the re-boiler of columns in unit were gained. For reaching to purified 1,3 butadiene, sensitivity of the process to the fluctuations of feed temperature and on the duties of the re-boilers of the columns is noticeable .
Petroleum and Reservoir Engineering
M. Nikpour; M. Pazouki
Volume 13, Issue 1 , January 2016, , Pages 32-46
Abstract
In this essay, lipase from Burkholderia cepacia was immobilized into 3-glycidoxypropyltrimethoxysilane (GPTMS) and tetramethoxysilane (TMOS) derived sol-gels. GPTMS:TMOS molar ratio of 1:3 was found to yield the best result. The morphological characteristics were investigated based on SEM and BET analysis. ...
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In this essay, lipase from Burkholderia cepacia was immobilized into 3-glycidoxypropyltrimethoxysilane (GPTMS) and tetramethoxysilane (TMOS) derived sol-gels. GPTMS:TMOS molar ratio of 1:3 was found to yield the best result. The morphological characteristics were investigated based on SEM and BET analysis. Sample mean pore diameter was 39.1 nm, it had a specific surface area of 60 m2/g prior to enzyme addition which decreased to 7.49 m2/g after immobilization. The enzyme activity was assessed through transesterification of waste cooking oil in the presence of ethanol with optimal conditions of: 40 ᵒC, 15 % immobilized lipase, 9:1 alcohol to oil molar ratio in 24 h of reaction which resulted to 91.70 % biodiesel production. In six-hour reaction time, 86.87 % biodiesel was obtained which is much shorter than conventional enzymatic transesterification which is 72 hours. Ethyl esters were characterized by determining their viscosity, density, and flash point based on ASTM D 6751-07b standards.
Environmental Engineering,
V. Mortezaeikia; R. Yegani; M.A. Hejazi; S. Chegini
Volume 13, Issue 1 , January 2016, , Pages 47-59
Abstract
In this work, performance of hollow fiber membrane photobioreactor (HFMPB) on the growth of Dunaliella Salina (G26) at various aeration rates (0.1 and 0.2 VVm) and medium re-circulation flow rates (500 and 1000 mL/h) were studied. Cultivation was carried out at both batch and semi-continuous modes in ...
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In this work, performance of hollow fiber membrane photobioreactor (HFMPB) on the growth of Dunaliella Salina (G26) at various aeration rates (0.1 and 0.2 VVm) and medium re-circulation flow rates (500 and 1000 mL/h) were studied. Cultivation was carried out at both batch and semi-continuous modes in HFMPBs containing neat and hydrophilized in-house fabricated poly ethylene (PE) membranes at fixed light intensity of 300 µmol m-2 s-1and temperature of 30 oC. Microalgae showed better growth in hydrophobic module in both cultivation modes and modules. Maximum biomass concentration, CO2 biofixation and specific growth rates equal with 0.71g L-1, 1.102g L-1 d-1 and 0.224d-1 were obtained for non-wetted membranes, respectively. Comparing the performance of both modules showed that the impact of cultivation mode on the CO2 biofixation rate and CO2 removal is more pronounced than the impact of mass transfer resistance in membrane contactors. The obtained results show that the mean CO2 biofixation rates in semi-continuous cultivation for both neat and hydrophilized modules are higher than that in batch cultivation in all operating conditions. It was also found that the hydrophobic membranes are much preferable than hydrophilic membrane in HFMPBs.
Reaction Engineering, Kinetics and Catalysts,
Mohammad Pazouki; Ali Zakeri; Manoucher Vossoughi
Volume 12, Issue 4 , October 2015, , Pages 84-92
Abstract
In this research, unstructured kinetic modeling for cell growth evaluation by X.campestris, xanthan production and sugar cane molasses consumption in a batch culture were investigated. Logistic model for biomass growth, Luedeking-Piret model for xanthan biopolymer production and modified Luedeking-Piret ...
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In this research, unstructured kinetic modeling for cell growth evaluation by X.campestris, xanthan production and sugar cane molasses consumption in a batch culture were investigated. Logistic model for biomass growth, Luedeking-Piret model for xanthan biopolymer production and modified Luedeking-Piret model for sugar cane molasses consumption provides an accurate prediction of the fermentation kinetics parameters with high coefficient of determination R2 values.Luedeking-Piret model for xanthan biopolymer production in three different concentration of sugar cane molasses (30, 60 and 90 g/l) as the sole carbon source substrate were studied. A good agreement between experimental and predicted values indicated that the unstructured models were able to describe this fermentation process successfully. The values of specific growth rate μ_max of logestic model for sugar cane molasses (30, 60 and 90 g/l) were 0.029, 0.031 and 0.032 h-1 respectively. The values of α and β is 5.280, 6.594, 8.518 and 0.072, 0.066, 0.086 respectively which shows that the xanthan production is growth associated since the value of the growth associated parameter α is much more than the value of nongrowth associated parameter β in Luedeking Piret model. Moreover, the values of γ and 𝜂 in modified Luedeking-Piret model were obtained.