Zahra Mansourpour; Shohreh Fatemi; Ali Reza Khanchi
Abstract
Feasibility of using Cyanex 301, as the auxiliary agent, for supercritical extraction of Cupper and Manganese cations from solid matrix was studied statistically. The amount of extraction is influenced by several parameters, such as amount of ligand, pressure, temperature, SCCO2 flow rate, time of extraction ...
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Feasibility of using Cyanex 301, as the auxiliary agent, for supercritical extraction of Cupper and Manganese cations from solid matrix was studied statistically. The amount of extraction is influenced by several parameters, such as amount of ligand, pressure, temperature, SCCO2 flow rate, time of extraction and amount of acid. Recent researches showed that factorial design is an effective tool for optimization of the operational conditions. A 26-3 fractional factorial design was used to derive the most effective parameters affecting the yield of extraction. Using analysis of variance and pooling method, the significant parameters were determined and separated from insignificant factors, and then main effects and their binary interactions were obtained. It was concluded that at high pressure (above 200 bar), the amount of acid, temperature and CO2 flow rate have significant effect on Cu extraction. The amount of the ligand showed positive effect on Mn extraction. As a result, it is possible to separate Cu2+ from Mn2+ by SCCO2 at appropriate conditions from solid matrix more than 95%.
Mohammad Mehdi Montazer Rahmati; Seyyed Hossein Ghafeleh Bashi
Abstract
Process control of a spray dryer that is usually used as the last step of production is very crucial in obtaining a quality standard product. To this end, predicting the effect of various operating and environmental parameters on product properties is essential. Modeling was done in microscopic and macroscopic ...
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Process control of a spray dryer that is usually used as the last step of production is very crucial in obtaining a quality standard product. To this end, predicting the effect of various operating and environmental parameters on product properties is essential. Modeling was done in microscopic and macroscopic scales by modifying the mass and heat transfer equations used in investigating the drying mechanism. However, as far as momentum transfer is concerned, the equations are the same as the ones used in the available literature models. Unlike conventional models that take only the two streams of hot air and sprayed droplets into account, a third stream is considered in our proposed model and this modification improved the results significantly. The model equations were solved numerically and a new simulation software was developed using Visual C++ 6.0. The model results are in good agreement with the industrial data obtained from a detergent producing plant.
Mohammad Mehdi Montazer Rahmati; Seyyed Jaber Safdari; Hossein Akhgari
Abstract
Holdup was measured at various frequencies, amplitudes, continuous and dispersed phase flow rates for binary systems in a pulsed plate column capable of providing samples at various heights. The binary systems was so selected as to cover a wide spectrum of interfacial tensions. Dispersed phase holdup ...
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Holdup was measured at various frequencies, amplitudes, continuous and dispersed phase flow rates for binary systems in a pulsed plate column capable of providing samples at various heights. The binary systems was so selected as to cover a wide spectrum of interfacial tensions. Dispersed phase holdup was found to increase with height in a logarithmic fashion at conditions away from the flooding point and to become almost invariant with height near flooding conditions. The interfacial tension of the binary system has a large effect on the dispersed phase holdup. In systems having low interfacial tension, a small increase in any of the parameters can increase the holdup significantly and lead to flooding. In systems having high interfacial tension, on the other hand, variations in system parameters do not affect system performance significantly.
Homa Keshavarzi Shirazi; Ayyoub Torkian; Ali Akbar Azimi; Naser Mehrdadi
Abstract
Performance of a pilot Biofiltration system in removing of Triethylamine (TEA) vapor from air stream was evaluated in this study. Experiments were conducted with two 6-L three section biofilters containing a mixture of compost (60%) and wood chips (40%). The systems were operated at 20±2 and 30±1 ?C. ...
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Performance of a pilot Biofiltration system in removing of Triethylamine (TEA) vapor from air stream was evaluated in this study. Experiments were conducted with two 6-L three section biofilters containing a mixture of compost (60%) and wood chips (40%). The systems were operated at 20±2 and 30±1 ?C. Municipal activated sludge was added initially to promote microbial growth and the systems were started after initial adaptation period of 40 days. Various loading rates (8-130 g/m3.hr) and detention times (40-60 seconds) were studied to evaluate the effect on performance of biofilter for TEA removal. Results indicated significant decrease in EC for HRT < 48 s but negligible differences were observed between 60 and 48 s. TEA removal in section one was significant higher than the other two. Maximum E.C. of 61 g/m3.hr at HRT of 48 second, humidity of 50-55 %, and loading rate of 90.6 g/m3.hr was observed for the reactor A. Maximum E.C. of 72 g/m3.hr at HRT of 48 s, humidity of 50-55 %, and loading rate of 114.4 g/m3.hr was observed for the reactor B having a higher temperature.
Sohrabali Ghorbanian; Hossein Abolghasemi; Mohammad Ali Mousavian; Sa'eed Reza Radpour
Sohrabali Ghorbanian; Hossein Abolghasemi; Seyyed Mohammad Ali Mousavian
Abstract
In this research paper, an experimental breakthrough curve for citric acid in an adsorption recovery process was determined by an ion-exchange resin in 20, 35, 55 °C. Also, a mathematical model for breakthrough curve was presented. Among ion exchange resins that have been experienced, many weak and ...
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In this research paper, an experimental breakthrough curve for citric acid in an adsorption recovery process was determined by an ion-exchange resin in 20, 35, 55 °C. Also, a mathematical model for breakthrough curve was presented. Among ion exchange resins that have been experienced, many weak and strong basic anionic resins are available such as, IRA-92, IRA-93, IRA-420 and IRA-458 and all of them were experienced in this work. It was shown that IRI-93 has good performance and compatibility. To obtain concentration of citric acid in the outlet stream from the resin glass column, spectrophotometer UV-VIS, Cary 1E/ Cary 3E from Varian Company was used. The results indicated weak basic kinds are suitable for organic acids recovery, especially for citric acid. Also, the results showed that Amberlite IRA-93 is one of the best resins for recovery of citric acid. In the transient state adsorption, the breakthrough isothermal adsorption curve was obtained in different temperatures. Generally, although an increase in temperature causes an increase in diffusion coefficient of particles, the saturation capacity of resin (or the effective adsorption of acid in the bed) decreases. Several models in different forms, such as fractional, polynomial and exponential, were developed and with analyzing these models a new mathematical model in the form of and modified form of were developed for prediction of the breakthrough curve with low error. Also, if the model is to be used for the break through curve between start and terminal rapture points, the situation of fitting is in the best condition and error less than 1% could be achieved. In this way, least square method in Eviews software was applied. With using these models, the variation of similar breakthrough curves could be fitted, appropriately.
Seyyed Nad Ali Ghadami; Manouchehr Haghighi; Ali Reza Behbahani Nia
Mohammad Reza Talaghat; Abdolhossein Jahanmiri
Abstract
This paper presents a study on estimation of heat transfer coefficient and thermal diffusivity parameters by use of analytical solutions and experimental data for regular geometries (infinite slab, infinite cylinder and sphere). Analytical solutions have a broad use in experimentally determining these ...
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This paper presents a study on estimation of heat transfer coefficient and thermal diffusivity parameters by use of analytical solutions and experimental data for regular geometries (infinite slab, infinite cylinder and sphere). Analytical solutions have a broad use in experimentally determining these parameters. These solutions, with use of experimental data, might give a greater advantage over use of other methods, e.g., the lumped system approach or empirical equations. In the present work, the method of finite integral transform (FIT) was used for solutions of governing differential equations. The temperature change at centerline location of cylindrical objects (Aluminum and Brass) were recorded to determine both the thermal diffusivity in a highly agitated water medium and heat transfer coefficient in air and water mediums . Then, with the known slop of the temperature ratio vs. time curve and radius of the cylindrical material, thermal diffusivity value or heat transfer coefficient may be determined. For all experiments, excellent agreement was obtained between the experimental results and the actual data. This method may also be used to find out the precise geometric location of the thermocouples placed in the samples to measure the temperature change. In this research, thermocouple location for a spherical object was determined. This technique would be much faster and easier compared to the other methods used for this objective.
Hamid Reza Shahverdi; Manouchehr Haghighi; Kazem Fouladi
Maryam Mashayekhi; Reza Rousta Azad
Abstract
The Tagouchi method was used for providing the instruction of ultra-filter dairy membrane cleaning. The goal function with using of four undimentionalized parameter, i.e., water and milk serum flux, percent of protein and dry mass of permeate, as quality indicator of cleaning of cleaned membrane, was ...
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The Tagouchi method was used for providing the instruction of ultra-filter dairy membrane cleaning. The goal function with using of four undimentionalized parameter, i.e., water and milk serum flux, percent of protein and dry mass of permeate, as quality indicator of cleaning of cleaned membrane, was defined. As a result, basic cleaning solution was found as follows: 0.8% NaOH, 1.0% EDTA, 1.0% Sodium di Hydrogen Phosphate, 0.1% Sodium Carbonate and 0.2% SDS. Cleaning with this solution at first step for 90 min and at second step for 20 min in 50°C was found suitable. The optimum acidic solution was obtained as 0.3% Nitric Acid, 0.01% Phosphoric Acid and 0.15% Marlophen. Cleaning with this solution for 60 min at 30°C has serious effect on membrane cleaning. In addition, using of lipase and protease in cleaning operation was studied. The results showed that protease is 4.39% stronger than lipase. It is shown that the serious effect of protein components is more than oily components on fouling of dairy membrane.
Ali Haghighi Asl; Akbar Shahsavand; Mohammad Reza Ghorbani
Abstract
In the present article an energy distribution function of heterogeneous solid was estimated. Energy distribution function is an important characterization for heterogeneous adsorbent. An overall adsorption quantity for a heterogeneous solid is usually expressed by a first kind of Fredholm equation, which ...
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In the present article an energy distribution function of heterogeneous solid was estimated. Energy distribution function is an important characterization for heterogeneous adsorbent. An overall adsorption quantity for a heterogeneous solid is usually expressed by a first kind of Fredholm equation, which contains unknown distribution function and local adsorption isotherm as a kernel. The calculation of this distribution function is an ill-posed problem. The current article shows that the difficulties arising from the ill-posed nature of an adsorption equation can be overcome with the linear regularization method and inverse theory. Performance of the regularization method for calculation multipeak energy distribution functions was examined in the present work. The results expressed with different charts and several random errors. The results showed that linear regularization method is very convenient for prediction of energy distribution function of heterogeneous solids. Furthermore, if a large amount of data at low pressure is available, the performance of this method would be very suitable. Therefore, in the most cases that some data have a large random error (about 50 %), regularization method can predict the energy distribution function satisfactorily.
Ali Asghar Hamidi; Kourosh Shafi'ee
Morteza Hosseini
Abstract
This study is about the non-uniform electric field for splitting of water in oil emulsion. If the process occurs in an inhomogeneous electrical field, the drops are polarized and then their mobility is increased. The emulsion drops will be charged and move toward the central point of splitter where the ...
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This study is about the non-uniform electric field for splitting of water in oil emulsion. If the process occurs in an inhomogeneous electrical field, the drops are polarized and then their mobility is increased. The emulsion drops will be charged and move toward the central point of splitter where the maximum intensity of electrical field has been concentrated. In this process, the drops encounter and form bigger and heavier drops, which are settled down due to gravity. Using the non-uniform electric method with 10500 Volt intensity, 50 Hertz frequency and 1 degree Celsius temperature, the 99 % splitting of emulsion was observed.
