In this study, the thin-layer drying characteristics of Figs (Ficus carica) are investigated in a... more In this study, the thin-layer drying characteristics of Figs (Ficus carica) are investigated in a pilot scale forced convective dryer. Experiments carried out under various operating conditions including air temperature (40, 50, 60, 70°C), air velocity (0.65, 2.1, 3.45, 4.85 m/s) and air humidity (0.005, 0.010, 0.015 kg/kg) and the effects of these operating conditions on the drying kinetics and the drying time determined. The obtained kinetics data are fitted into a conceptually developed model. The equilibrium moisture content of the dried figs is determined at different values of temperature and relative humidity of air. The values of effective moisture diffusivity (Deff) are obtained from the Fick’s second law and a temperature-dependent relation is proposed for this parameter.
Seven strains isolated from DSO (disulfide oil) contaminated soils. Among them, two strains had h... more Seven strains isolated from DSO (disulfide oil) contaminated soils. Among them, two strains had high potential to remove DSO from contaminated soils. These strains identified as Paenibacillus (a gram positive, nitrogen fixing spore, spore forming bacillus) and Rhodococcus (a gram positive, catalase positive, acid fast forming bacteria), by preliminary tests. The optimal conditions for DSO removal from contaminated soils were
ABSTRACT In this work, which was designed for drying of agro-food products, six varieties of pota... more ABSTRACT In this work, which was designed for drying of agro-food products, six varieties of potatoes (Santana, Santea, Marfona, Diamant, Koncord, Renjer) were chosen as drying material. A pilot-scale tray dryer, with and without air circulation, and a fluidized bed dryer were used for performing drying experiments. The experiments were performed with and without blanching. The changes in structure and colour of six varieties of potatoes were studied.Temperature did not show significant effect on shrinkage, but blanching time and air circulation had significant effect on shrinkage as well as on the appearance of dried product. Less shrinkage occurred in Renjer and Diamant varieties at 80°C in comparison with other varieties. Santana (at 80°C), Santea (at 70°C) and Renjer (at 80°C) had better appearance and colour after free convection drying, whereas the appearance, colour and quality of Marfona variety was not acceptable at all. The quality and appearance of Marfona variety improved by using a tray dryer with air circulation. The quality and appearance of all varieties was very good in fluidized bed dryer. Blanching was effective in improving the colour of all dried varieties.
An isolate from polluted soil identified as Aspergillus sp. MS-100 was able to consume vanadium o... more An isolate from polluted soil identified as Aspergillus sp. MS-100 was able to consume vanadium oxide octaethyl porphyrin as a model for protoporphyrins in crude oil. The isolate degrades about 55% of vanadium oxide octaethyl porphyrin (VOOEP) under optimum conditions during 7 days. The release of more than 0.96 mgl -1 of free vanadium into the aqueous phase was confirmed using atomic absorption. By using the Taguchi experimental design method, the optimum values of pH, temperature and initial concentration of VOOEP were determined as 5.5, 30oC, and 20 mg/l, respectively. The reduction of VOOEP in the culture medium was accelerated by Ag + and inhibited by Zn2+ and EDTA. The Sn2+ and Pb2+ ions showed a stimulatory effect at 0.1 mM and an inhibitory effect at 1 mM.
Abstract In this study, an air-cathode-aluminum-air desalination battery as a new technology for ... more Abstract In this study, an air-cathode-aluminum-air desalination battery as a new technology for simultaneous desalination and electrical power generation was developed through the optimization of its operating parameters. Nitrogen-sulfur co-doped carbon was synthesized and characterized as a cheap and efficient catalyst for oxygen reduction reaction in the cathode. By optimizing the aluminum anode parameters, utilizing the fabricated air-cathode and modifying the operational conditions, the salt removal and average generated energy reached 2.06 g/L (in 90 min) and 0.55 Wh/L of the processed water, respectively, consuming 0.26 g of aluminum per hour. Moreover, using cost analysis this technology was found competitive with other desalination systems for high salinity water, consuming 2.05 Wh for 1 g salt removal with initial salinity of 12 g/L. Overall, this assembly is a low cost and environmentally friendly process, and with advantages such as continuous desalination and reasonable desalination rate, seems to be a promising candidate for desalination purposes.
ABSTRACT This article presents an experimental investigation of substituting R134a with R436A (a ... more ABSTRACT This article presents an experimental investigation of substituting R134a with R436A (a mixture of R290 and R600a with a mass ratio of 56/44) in a 238 L single evaporator domestic refrigerator without any modification in refrigeration cycle. The refrigerator’s compressor was charged with different amount of R436A, and in addition to refrigerator’s power consumption during operation, the temperatures in different sections of the refrigerator were measured. Results showed that in comparison to the base refrigerator working with R134a, the ON time ratio and the energy consumption per day were reduced by 13% and 5.3%, respectively. Although the original R134a charge for this refrigerator was 105 g, the optimum charge for R436A was reduced to 55 g that exhibits 48% reduction in refrigerant charge. Also replacing R134a charge with R436A raised the energy efficiency index of the refrigerator from label “E” to label “D” according to Iranian National Standard No. 4853-2.
In this work, which was designed for drying of agro-food products, six varieties of potatoes (San... more In this work, which was designed for drying of agro-food products, six varieties of potatoes (Santana, Santea, Marfona, Diamant, Koncord, Renjer) were chosen as drying material. A pilot-scale tray dryer, with and without air circulation, and a fluidized bed dryer were used for performing drying experiments. The experiments were performed with and without blanching. The changes in structure and colour of six varieties of potatoes were studied.Temperature did not show significant effect on shrinkage, but blanching time and air circulation had significant effect on shrinkage as well as on the appearance of dried product. Less shrinkage occurred in Renjer and Diamant varieties at 80°C in comparison with other varieties. Santana (at 80°C), Santea (at 70°C) and Renjer (at 80°C) had better appearance and colour after free convection drying, whereas the appearance, colour and quality of Marfona variety was not acceptable at all. The quality and appearance of Marfona variety improved by usin...
Seven strains isolated from DSO (disulfide oil) contaminated soils. Among them, two strains had h... more Seven strains isolated from DSO (disulfide oil) contaminated soils. Among them, two strains had high potential to remove DSO from contaminated soils. These strains identified as Paenibacillus (a gram positive, nitrogen fixing spore, spore forming bacillus) and Rhodococcus (a gram positive, catalase positive, acid fast forming bacteria), by preliminary tests. The optimal conditions for DSO removal from contaminated soils were
Previously, several mathematical models have been proposed for liquid-liquid extraction processes... more Previously, several mathematical models have been proposed for liquid-liquid extraction processes involving Rotating Disc Contactor (RDC) Column. Most of these models reveal that hydrodynamic and mass transfer phenomena are important for predicting the performance of the column. In this paper, a mathematical model, using a new scheme, was developed to acquire a simulation tool to predict the performance of an RDC column used in lubricating oil production. Field data obtained in an RDC column of from a commercial lubricating oil production company was used to evaluate the predictions. The model is used for parametric study of aromatics extraction from lube-oil cut in an RDC column to investigate the effects of operational data such as solvent and feed temperatures, solvent to feed ratio and disc rotation rate on the extraction yield. The developed model compares more favorably with other existing back-flow models by consideration of temperature, physical property and flow rate variat...
ABSTRACT Flue gas desulfurization of industrial plants using seawater is studied experimentally a... more ABSTRACT Flue gas desulfurization of industrial plants using seawater is studied experimentally and theoretically in a counter–current packed–bed tower. Experiments are carried out based on a 16–run orthogonal array of the Taguchi method (five factors, four levels) and ANOVA table created to determine the most significant controlling factors on SO2 removal efficiency. Liquid flow rate (1.5–4 l/min), gas temperature (50–350°C), gas flow rate (8–20 m3/h), and SO2 concentration (500–2000 ppmv) are revealed as important factors, while the pH of seawater (8–9.5) is not significant. Experimental results show that an increase in gas temperature causes a decrease in the removal efficiency. A mathematical model is developed for the removal of SO2 by seawater for non-isothermal operating conditions. In the modeling procedure the equilibrium reactions of eight dissolved species within the liquid phase are considered to calculate the kinetic of reaction correctly. The results of this study confirm the capability of seawater for SO2 removal in packed-bed towers.
ABSTRACT A pilot scale fluidized bed dryer with inert particles as energy carrier was used to inv... more ABSTRACT A pilot scale fluidized bed dryer with inert particles as energy carrier was used to investigate the drying characteristics of carrot in this type of dryer. Glass beads, hollow steel balls and pieces of dry carrot were used as inert materials. The effects of sample diameter, inert material type, inert material diameter, amount of inert material, air velocity and temperature on the rate of drying were studied. It was found that the presence of inert particles enhances the rate of drying. The results of this study also revealed that, although the rate of drying increased with decreasing sample diameter, increasing of inert material thermal conductivity, and increasing of air temperature, but the inert material diameter and air velocity did not have any significant effect on the rate of drying. The independence of the rate of drying on air velocity in well fluidized systems, indicates that external diffusion is not the controlling step in this process. It was also found that the presence of inert materials caused the drying material to reach its final internal temperature more rapidly. The internal temperature of the drying material, also increased with increasing diameter and thermal conductivity of the inert materials.
ABSTRACT A semi-empirical kinetic correlation was obtained through a shrinking core model assumpt... more ABSTRACT A semi-empirical kinetic correlation was obtained through a shrinking core model assumption for reactive absorption of CO2 with NaOH solution by applying response surface method analogy in a laboratory-scale spray-dryer absorber. The effect of approach temperature, absorbent concentration, nozzle diameter, and L/G ratio on the kinetic coefficient was studied and the optimum operating conditions to reach the maximum absorption were determined.
In this study, the thin-layer drying characteristics of Figs (Ficus carica) are investigated in a... more In this study, the thin-layer drying characteristics of Figs (Ficus carica) are investigated in a pilot scale forced convective dryer. Experiments carried out under various operating conditions including air temperature (40, 50, 60, 70°C), air velocity (0.65, 2.1, 3.45, 4.85 m/s) and air humidity (0.005, 0.010, 0.015 kg/kg) and the effects of these operating conditions on the drying kinetics and the drying time determined. The obtained kinetics data are fitted into a conceptually developed model. The equilibrium moisture content of the dried figs is determined at different values of temperature and relative humidity of air. The values of effective moisture diffusivity (Deff) are obtained from the Fick’s second law and a temperature-dependent relation is proposed for this parameter.
Seven strains isolated from DSO (disulfide oil) contaminated soils. Among them, two strains had h... more Seven strains isolated from DSO (disulfide oil) contaminated soils. Among them, two strains had high potential to remove DSO from contaminated soils. These strains identified as Paenibacillus (a gram positive, nitrogen fixing spore, spore forming bacillus) and Rhodococcus (a gram positive, catalase positive, acid fast forming bacteria), by preliminary tests. The optimal conditions for DSO removal from contaminated soils were
ABSTRACT In this work, which was designed for drying of agro-food products, six varieties of pota... more ABSTRACT In this work, which was designed for drying of agro-food products, six varieties of potatoes (Santana, Santea, Marfona, Diamant, Koncord, Renjer) were chosen as drying material. A pilot-scale tray dryer, with and without air circulation, and a fluidized bed dryer were used for performing drying experiments. The experiments were performed with and without blanching. The changes in structure and colour of six varieties of potatoes were studied.Temperature did not show significant effect on shrinkage, but blanching time and air circulation had significant effect on shrinkage as well as on the appearance of dried product. Less shrinkage occurred in Renjer and Diamant varieties at 80°C in comparison with other varieties. Santana (at 80°C), Santea (at 70°C) and Renjer (at 80°C) had better appearance and colour after free convection drying, whereas the appearance, colour and quality of Marfona variety was not acceptable at all. The quality and appearance of Marfona variety improved by using a tray dryer with air circulation. The quality and appearance of all varieties was very good in fluidized bed dryer. Blanching was effective in improving the colour of all dried varieties.
An isolate from polluted soil identified as Aspergillus sp. MS-100 was able to consume vanadium o... more An isolate from polluted soil identified as Aspergillus sp. MS-100 was able to consume vanadium oxide octaethyl porphyrin as a model for protoporphyrins in crude oil. The isolate degrades about 55% of vanadium oxide octaethyl porphyrin (VOOEP) under optimum conditions during 7 days. The release of more than 0.96 mgl -1 of free vanadium into the aqueous phase was confirmed using atomic absorption. By using the Taguchi experimental design method, the optimum values of pH, temperature and initial concentration of VOOEP were determined as 5.5, 30oC, and 20 mg/l, respectively. The reduction of VOOEP in the culture medium was accelerated by Ag + and inhibited by Zn2+ and EDTA. The Sn2+ and Pb2+ ions showed a stimulatory effect at 0.1 mM and an inhibitory effect at 1 mM.
Abstract In this study, an air-cathode-aluminum-air desalination battery as a new technology for ... more Abstract In this study, an air-cathode-aluminum-air desalination battery as a new technology for simultaneous desalination and electrical power generation was developed through the optimization of its operating parameters. Nitrogen-sulfur co-doped carbon was synthesized and characterized as a cheap and efficient catalyst for oxygen reduction reaction in the cathode. By optimizing the aluminum anode parameters, utilizing the fabricated air-cathode and modifying the operational conditions, the salt removal and average generated energy reached 2.06 g/L (in 90 min) and 0.55 Wh/L of the processed water, respectively, consuming 0.26 g of aluminum per hour. Moreover, using cost analysis this technology was found competitive with other desalination systems for high salinity water, consuming 2.05 Wh for 1 g salt removal with initial salinity of 12 g/L. Overall, this assembly is a low cost and environmentally friendly process, and with advantages such as continuous desalination and reasonable desalination rate, seems to be a promising candidate for desalination purposes.
ABSTRACT This article presents an experimental investigation of substituting R134a with R436A (a ... more ABSTRACT This article presents an experimental investigation of substituting R134a with R436A (a mixture of R290 and R600a with a mass ratio of 56/44) in a 238 L single evaporator domestic refrigerator without any modification in refrigeration cycle. The refrigerator’s compressor was charged with different amount of R436A, and in addition to refrigerator’s power consumption during operation, the temperatures in different sections of the refrigerator were measured. Results showed that in comparison to the base refrigerator working with R134a, the ON time ratio and the energy consumption per day were reduced by 13% and 5.3%, respectively. Although the original R134a charge for this refrigerator was 105 g, the optimum charge for R436A was reduced to 55 g that exhibits 48% reduction in refrigerant charge. Also replacing R134a charge with R436A raised the energy efficiency index of the refrigerator from label “E” to label “D” according to Iranian National Standard No. 4853-2.
In this work, which was designed for drying of agro-food products, six varieties of potatoes (San... more In this work, which was designed for drying of agro-food products, six varieties of potatoes (Santana, Santea, Marfona, Diamant, Koncord, Renjer) were chosen as drying material. A pilot-scale tray dryer, with and without air circulation, and a fluidized bed dryer were used for performing drying experiments. The experiments were performed with and without blanching. The changes in structure and colour of six varieties of potatoes were studied.Temperature did not show significant effect on shrinkage, but blanching time and air circulation had significant effect on shrinkage as well as on the appearance of dried product. Less shrinkage occurred in Renjer and Diamant varieties at 80°C in comparison with other varieties. Santana (at 80°C), Santea (at 70°C) and Renjer (at 80°C) had better appearance and colour after free convection drying, whereas the appearance, colour and quality of Marfona variety was not acceptable at all. The quality and appearance of Marfona variety improved by usin...
Seven strains isolated from DSO (disulfide oil) contaminated soils. Among them, two strains had h... more Seven strains isolated from DSO (disulfide oil) contaminated soils. Among them, two strains had high potential to remove DSO from contaminated soils. These strains identified as Paenibacillus (a gram positive, nitrogen fixing spore, spore forming bacillus) and Rhodococcus (a gram positive, catalase positive, acid fast forming bacteria), by preliminary tests. The optimal conditions for DSO removal from contaminated soils were
Previously, several mathematical models have been proposed for liquid-liquid extraction processes... more Previously, several mathematical models have been proposed for liquid-liquid extraction processes involving Rotating Disc Contactor (RDC) Column. Most of these models reveal that hydrodynamic and mass transfer phenomena are important for predicting the performance of the column. In this paper, a mathematical model, using a new scheme, was developed to acquire a simulation tool to predict the performance of an RDC column used in lubricating oil production. Field data obtained in an RDC column of from a commercial lubricating oil production company was used to evaluate the predictions. The model is used for parametric study of aromatics extraction from lube-oil cut in an RDC column to investigate the effects of operational data such as solvent and feed temperatures, solvent to feed ratio and disc rotation rate on the extraction yield. The developed model compares more favorably with other existing back-flow models by consideration of temperature, physical property and flow rate variat...
ABSTRACT Flue gas desulfurization of industrial plants using seawater is studied experimentally a... more ABSTRACT Flue gas desulfurization of industrial plants using seawater is studied experimentally and theoretically in a counter–current packed–bed tower. Experiments are carried out based on a 16–run orthogonal array of the Taguchi method (five factors, four levels) and ANOVA table created to determine the most significant controlling factors on SO2 removal efficiency. Liquid flow rate (1.5–4 l/min), gas temperature (50–350°C), gas flow rate (8–20 m3/h), and SO2 concentration (500–2000 ppmv) are revealed as important factors, while the pH of seawater (8–9.5) is not significant. Experimental results show that an increase in gas temperature causes a decrease in the removal efficiency. A mathematical model is developed for the removal of SO2 by seawater for non-isothermal operating conditions. In the modeling procedure the equilibrium reactions of eight dissolved species within the liquid phase are considered to calculate the kinetic of reaction correctly. The results of this study confirm the capability of seawater for SO2 removal in packed-bed towers.
ABSTRACT A pilot scale fluidized bed dryer with inert particles as energy carrier was used to inv... more ABSTRACT A pilot scale fluidized bed dryer with inert particles as energy carrier was used to investigate the drying characteristics of carrot in this type of dryer. Glass beads, hollow steel balls and pieces of dry carrot were used as inert materials. The effects of sample diameter, inert material type, inert material diameter, amount of inert material, air velocity and temperature on the rate of drying were studied. It was found that the presence of inert particles enhances the rate of drying. The results of this study also revealed that, although the rate of drying increased with decreasing sample diameter, increasing of inert material thermal conductivity, and increasing of air temperature, but the inert material diameter and air velocity did not have any significant effect on the rate of drying. The independence of the rate of drying on air velocity in well fluidized systems, indicates that external diffusion is not the controlling step in this process. It was also found that the presence of inert materials caused the drying material to reach its final internal temperature more rapidly. The internal temperature of the drying material, also increased with increasing diameter and thermal conductivity of the inert materials.
ABSTRACT A semi-empirical kinetic correlation was obtained through a shrinking core model assumpt... more ABSTRACT A semi-empirical kinetic correlation was obtained through a shrinking core model assumption for reactive absorption of CO2 with NaOH solution by applying response surface method analogy in a laboratory-scale spray-dryer absorber. The effect of approach temperature, absorbent concentration, nozzle diameter, and L/G ratio on the kinetic coefficient was studied and the optimum operating conditions to reach the maximum absorption were determined.
Uploads