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R. Parvizsedghy; M. Alibolandi; S. M. Sadrameli
Abstract
Vegetable oils are proved as valuable feedstocks in the biofuel production. Some common issues of cracking of vegetable oils–as an effective method for the biofuel production- are related to the glycerol decomposition during the cracking process. Transesterification, which can remove glycerol from ...
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Vegetable oils are proved as valuable feedstocks in the biofuel production. Some common issues of cracking of vegetable oils–as an effective method for the biofuel production- are related to the glycerol decomposition during the cracking process. Transesterification, which can remove glycerol from vegetable oil molecules, is performed before the thermal cracking to adjust the problems. This study has been aimed at surveying the efficiency of transesterification and the thermal cracking integration to produce bio-gasoline and bio-oil from castor oil. In transesterification, methanol as alcohol and KOH as catalyst were used, and the catalyst concentration, reaction temperature, and alcohol to oil ratio were effective variables. Statistical studies demonstrated the interactions among parameters and the yield of the methyl ester production as 96.7 % under the optimized conditions. Results showed that in the thermal cracking two parameters, of the feed flowrate and temperature, influenced the product yield significantly without any interaction. Under the optimum conditions, to maximize the bio-gasoline production, 28 % of bio-gasoline and 88.6 % of bio-oil were produced. The lack of acrolein, as a toxic component, the negligible amount of the generated water in the product, the high octane number, the significant amount of the heat of combustion of bio-gasoline, and being in criteria of standard gasoline as per ASTM D4814 for the distillation curve and RVP of bio-gasoline, were the great advantages of the cracking of the transesterified caster oil. Therefore, the bio-gasoline produced via the thermochemical conversion of castor oil could be used as a fuel for spark-ignition engines or as an octane enhancer with gasoline, i.e., by adding 10 % of bio-gasoline to the refinery gasoline, the octane number increased from 95 to 105.
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M. Mozafari; A. Ganjizade; .S. N. Ashrafizadeh
Abstract
In this work, the demulsification of water-in-crude oil emulsions by dielectrophoresis via applying a non-uniform electric field in a lab-scale cylindrical cell was studied. The stability of emulsions was assessed through monitoring the size distribution of water droplets at 0, 3, 6, and 24 hours after ...
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In this work, the demulsification of water-in-crude oil emulsions by dielectrophoresis via applying a non-uniform electric field in a lab-scale cylindrical cell was studied. The stability of emulsions was assessed through monitoring the size distribution of water droplets at 0, 3, 6, and 24 hours after the preparation of emulsion. The effect of operating parameters including the temperature, demulsifier concentration, water salinity, and time on the demulsification of water was investigated. Sodium dodecyl sulfate and sodium chloride were used as demulsifier and salt respectively. The experiments were designed by the response surface methodology (RSM) based on the central composite design (CCD). The operating parameters including the voltage, temperature, demulsifier concentration, salinity of water, and separation time were optimized. The contours and 3-D response surfaces of the water separation were acquired. A quadratic polynomial model, which was statistically highly significant (R2=0.9950, n=32), was provided by the RSM to predict the amount of the separated water. Comparison among the experimental and RSM-optimized values indicates a good agreement. The optimum amount of the water separation was obtained at the voltage of 15 kV, temperature of 60 °C, demulsifier concentration of 123 ppm, salinity of water of 12260 ppm, and separation time of 12.4 minutes. Under such conditions, the separation of water reached 98 %. The results obviously show that the electric field can be used as an appropriate means for the breakage of W/O emulsions.
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N. Mirhoseini renani; N. Etesami
Abstract
The electrohydrodynamic (EHD) drying of Poly (vinyl acetate) latex films was experimentally investigated in a wind tunnel. The influence of various conditions such as the air temperature, air velocity, and concentration of the latex solution, in the presence and the absence of a high electric field, ...
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The electrohydrodynamic (EHD) drying of Poly (vinyl acetate) latex films was experimentally investigated in a wind tunnel. The influence of various conditions such as the air temperature, air velocity, and concentration of the latex solution, in the presence and the absence of a high electric field, was investigated. The effects of the applied voltage intensity, electrode gap, number of needle electrodes, and polarity of corona on the drying rate of polymer films were studies. The drying behavior of films in a wind tunnel was observed by the weighting method and analyzed based on the heat and mass transfer. Results showed the importance of the EHD role in the drying rate of the polymer film. Increasing the intensity of the electric field, number, and configuration of needle electrodes, and decreasing the electrode gap lead to a significant enhancement of the drying rate of the polymer film. Scanning electron microscope (SEM) images were used to analyze the effect of EHD on the morphology of dried films.
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N. Sadeghi; O. Bakhtiari
Abstract
New promising generations of mixed matrix membranes (MMMs), which potentially have better separation performances than the neat polymeric membranes, are prepared by the incorporation of proper filler particles within polymeric matrices. However, some undesired phenomena like the void formation around ...
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New promising generations of mixed matrix membranes (MMMs), which potentially have better separation performances than the neat polymeric membranes, are prepared by the incorporation of proper filler particles within polymeric matrices. However, some undesired phenomena like the void formation around the filler particles limit this potential improvement. Having proper models is necessary to elucidate the impacts of this phenomenon on the MMMs’ separation performance. Different models have been developed but they are not able to predict the impact(s) of formed voids truly and their predicted void permeabilities are usually overestimated. In this study, the new parameter of the modified filler volume fraction considering the MMM swollen structure due to the formed voids around the filler particles, is employed along with the formed voids’ permeabilities correction factor, as ß, to modify the Maxwell, Bruggeman and Pal models for the MMMs’ permeability prediction. Absolute average relative errors (AAREs) of the modified models predicted that MMMs’ permeabilities or selectivities were considerably reduced to 3.16, 29.92, and 21.95 % from those of the Maxwell, Bruggeman, and Pal models as 31.33, 310.64, and 67.10 % respectively. Additionally, the optimum thicknesses of the formed voids around the filler particles rationally agree with the Knudsen flow concepts.
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M. Zangouie; A. Hemmati; M. Kian; J. Shayegan
Abstract
The membrane bioreactor (MBR) is a treatment bioreactor of urban and industrial wastewaters. The advantages of the MBR technology encompass high-quality effluents, less space requirements, and high-speed startups. This study aims to investigate the fouling phenomenon in the flour industry sewage ...
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The membrane bioreactor (MBR) is a treatment bioreactor of urban and industrial wastewaters. The advantages of the MBR technology encompass high-quality effluents, less space requirements, and high-speed startups. This study aims to investigate the fouling phenomenon in the flour industry sewage treatment. The pilot has been designed and constructed in line with the research concerning the industrial wastewater treatment. After the adaptation of microorganisms, physical and chemical tests such as chemical oxygen demands (COD), turbidity and total suspended solids (TSS), extracellular polymeric substances (EPS), and soluble microbial products (SMP) were conducted during the process. The concentration of mixed liquor suspended solids (MLSS) in the membrane bioreactor ranged between 5000 and 8500 mg/L. Hydraulic retention times (HRTs) were fixed at 4, 8, and 16 h. Three types of resistance were considered via measuring the leakage current and transmembrane pressure (TMP). Accordingly, the total resistance rates for HRTs of 4, 8, and 16h were 22.5×1010, 21.3×1010, and 20.4×1010 m-1 respectively. Considering the average organic loading rate (OLR) in three HRTs of 4, 8, and 16 h (8.84, 5.13, and 2.84 kg the COD/m3×day respectively), the daily feed was provided to the bioreactor, and the removal efficiency of COD was assessed. An average removal of 95 % was achieved in the whole process. In this method, the input turbidity of the effluent has been increased to 187 NTU and, then, reduced to less than 3 NTU. It was also observed that EPS, SMP, and the extracted carbohydrates played more vital roles in the membrane biofouling than the extracted proteins.
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A. Alipour; R. Sotude.Gharebagh; M. Koksal; G. Kulah; R. Zarghami; N. Mostoufi
Abstract
The attrition of 300 µm natural zeolite particles was studied in a laboratory scale draft tube spouted bed (DTSB) and spout-fluid bed (DTSFB). It has been shown that the attrition rate decreases with time and reaches to an almost constant value. The results show that the prevailing attrition mechanism ...
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The attrition of 300 µm natural zeolite particles was studied in a laboratory scale draft tube spouted bed (DTSB) and spout-fluid bed (DTSFB). It has been shown that the attrition rate decreases with time and reaches to an almost constant value. The results show that the prevailing attrition mechanism under the conditions of this work is the surface abrasion which occurs due to the collisions between particles. It has been found that increasing the cone angle from 30º to 60º in the DTSB, causes a decrease in the extent of attrition. In addition, by increasing the spouting air velocity and the height of the entrainment zone in the DTSB, the extent of attrition increases due to a more energetic collision between particles as well as the increased circulation rate of solids. Increasing the auxiliary air velocity in the DTSFB increases the rate of attrition. A comparison between the attrition in the DTSB and DTSFB has been conducted and has indicated that applying the auxiliary air flow causes up to a 6 % increase in the extent of attrition. An empirical correlation is derived for evaluating the extent of the attrition in the DTSB and DTSFB. This empirical correlation is in good agreement with the experimental data.