Mohammadreza Omidkhah | Tarbiat Modares University (original) (raw)
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Papers by Mohammadreza Omidkhah
The Canadian Journal of Chemical Engineering, 2015
Journal of the Taiwan Institute of Chemical Engineers, 2015
Journal of Membrane Science, 2015
Journal of Natural Gas Science and Engineering, 2015
One of the safe and pressure relieving systems in oil and gas refineries as well as petrochemical... more One of the safe and pressure relieving systems in oil and gas refineries as well as petrochemical complexes, is the relief header with the flare stack being the last component. In this network all the excess gases are collected and sent to flare stack to be burnt. A great amount of these gas mixtures has a high heating value and in some cases it can even be used as the raw material for various units. It is clear that burning this gas mixture in flare stack causes environmental problems like air and noise pollution and also is a financial waste. In this paper a step by step approach and calculations are given to calculate and discuss flare gas recovery benefits for refineries. The method contains data gathering of flare line's composition and other conditions, simulating of data and calculate financial benefits for the case study by available equations. Therefore, Tabriz oil refinery flaring system and available equation for flare system are used as a case study. Flare gas mixtur...
The role of the feed analysis in the basic design engineering contract is studied in this article.
In this work, the cross-linked poly (vinyl alcohol)/formaldehyde with different blend composition... more In this work, the cross-linked poly (vinyl alcohol)/formaldehyde with different blend compositions (FA/PVA: 1, 3, 5 ratio%) were synthesized. In addition, different diethanolamine concentrations ranging from 15-45 wt % were investigated for membrane fabrication. Moreover, the membranes were characterized by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) and contact angle measurement. Furthermore, the effects of crosslinking agent content, amine concentration and feed pressure on CO2/CH4 transport properties were investigated in pure gas experiments. The results showed that CO2 and CH4 permeances decreased with increasing FA/PVA mass ratio, in comparison with uncross-linked membranes, although the selevtivities increased considerably. The highest selectivity (about 92.72) was achieved from PVA/FA(5wt%)/PTFE membrane. Moreover, it was found that CO2/CH4 selectivity was significantly decreased with increasing cross-linker/PVA mass ratio from 1 wt% to 5 wt%. On...
Iranian Polymer Journal
gas sweetening, facilitated transport membranes, gas separation, cross-linking, polyvinyl alcohol... more gas sweetening, facilitated transport membranes, gas separation, cross-linking, polyvinyl alcohol D eveloping new methods and technologies for CO 2 removal with a variety of applications, such as purification of synthesis gas, natural gas sweetening, and greenhouse gas sequestration are nowadays carried out in research works involving polymeric membranes. By employing suitable reactive carriers into the membrane matrix, the solubility and absorption rate of the reactive gas (i.e., CO 2 ) are enhanced. In facilitated transport membrane, the selective transport through the membrane occurs owing to a reversible reaction between the reactive carriers and the target gas, while in contrast the solution-diffusion is the dominant mechanism for permeation of inert gases such as CH 4 , N 2 and H 2 . In this work, the cross-linking of diethanolamine (DEA)-impregnated polyvinyl alcohol (PVA) by glutaraldehyde (GA) with different blend compositions (GA/PVA: 0.5, 1, 3, 5, 7 ratio%) were performed in the absence of an acid catalyst and organic solvents in order to avoid any interference in CO 2 facilitation reaction with DEA. The fabricated membranes were characterized by differential scanning calorimetry, Fourier transform infrared (FTIR) and scanning electron microscopy. Furthermore, the effects of cross-linking agent content and feed pressure on CO 2 /CH 4 transport properties were investigated in pure gas experiments. Finally, the cross-linked membranes showed reasonable CO 2 /CH 4 permselectivity indexes in comparison to uncross-linked membranes. The best-yield in CO 2 -selective membranes (DEA-PVA/GA (1 wt%)/PTFE) represented the best CO 2 /CH 4 selectivity of 91.13 for pure gas experiments.
International Journal of Greenhouse Gas Control, 2015
ABSTRACT
International Journal of Chemical Reactor Engineering, 2000
Ni/Al2O3 catalysts were synthesized by sol-gel method with various nickel loadings. Chemical and ... more Ni/Al2O3 catalysts were synthesized by sol-gel method with various nickel loadings. Chemical and physical properties of the catalysts were characterized by XRD and TPR techniques. X-ray diffraction patterns showed no peaks due to NiO species. Temperature-...
Despite the high energy demand in the industrialized world and the pollution problems caused by w... more Despite the high energy demand in the industrialized world and the pollution problems caused by widespread use of fossil fuels, the need for developing renewable energy sources with less environmental impacts are increasing. Biodiesel production is undergoing rapid and extensive technological reforms in industries and academia. The major obstacle in production and biodiesel commercialization path is production cost. Thus, in previous years numerous studies on the use of technologies and different methods to evaluate optimal conditions of biodiesel production technically and economically have been carried out. In this paper, a comparative review of the current technological methods so far used to produce biodiesel has been investigated. Four primary approaches to make biodiesel are direct use and blending of vegetable oils, micro-emulsions, thermal cracking (pyrolysis) and transesterification. Transesterification reaction, the most common method in the production of biodiesel, is emphasized in this review. The two types of transestrification process; catalytic and non-catalytic are discussed at length in the paper. Both advantages and disadvantages of the different biodiesel production methods are also discussed.
RSC Adv., 2015
ABSTRACT Olefins and paraffins are the main building blocks for many products in the petrochemica... more ABSTRACT Olefins and paraffins are the main building blocks for many products in the petrochemical industry. Various research studies have demonstrated the viability of polyimide membranes for high performance olefin/paraffin separation. Further advancements in this field require having a thorough understanding of both sorptive and diffusive factors of permeation. This research study presents an extensive analysis on using frame of reference/bulk flow and Maxwell-Stefan models in order to elaborate on the transport and prediction of the performance in the case of propylene/propane separation using polyimide membranes. Sorption data of pure gases are utilized to calculate the sorption level of gases in binary mixture. The contributions of kinetic and thermodynamic coupling effects (TCE) are assessed using Maxwell-Stefan approach. Moreover, the dual-mode diffusion coefficients are evaluated and optimized for achieving higher accuracy predictions in the case of binary gas mixture. The results reveal the significant role of thermodynamic compared to kinetic coupling effects in governing the transport properties. In overall, Maxwell-Stephan model with the contribution of TCEs offers improved predictions compared to frame of reference/bulk flow model. The findings highlight the inevitable role of taking into account the prominent interactions of feed components in model development for better prediction of performance and evaluation of propylene/propane separation unit using polyimide membranes.
Greenhouse Gases: Science and Technology, 2015
ABSTRACT
Journal of the Taiwan Institute of Chemical Engineers, 2014
This is the first report of gas transport properties of polymer Elvaloy4170. Elvaloy4170 is a com... more This is the first report of gas transport properties of polymer Elvaloy4170. Elvaloy4170 is a commercially available polymer, which has very low price and good mechanical properties. In this work, mixed matrix membranes (MMMs) were fabricated by embedding the multi-walled carbon nanotubes (MWNTs) into El-valoy4170. Additionally, the effects of functionalization of the nanotubes with acid treatment and their loadings were evaluated on morphology and gas permeation properties of the membranes. The fabricated membranes were characterized by Raman spectroscopy, field emission scanning electron microscopy (FESEM) and differential scanning calorimeter (DSC). Moreover, the effects of filler loading and feed pressure (from 2 to 6 bar) on CO 2 /CH 4 transport properties were considered in pure gas experiment. The gas permeability results of Elvaloy4170 membrane revealed that with increasing the pressure from 2 to 6 bar, CO 2 permeability and CO 2 /CH 4 selectivity increased 30% and 14%, respectively. Furthermore, compared to neat membrane, the MMM with 1 wt.% of f-MWNTs increased CO 2 and CH 4 permeabilities by 30% and 40%, respectively. In addition, it was found that the CO 2 /CH 4 selectivity increased as the content of f-MWNTs increased from 1 wt.% to 4 wt.% in the polymer matrix. Finally, this study reveals that membranes fabricated from commercial polymer Elvaloy4170 were permeable and have the great potential to be applied for other gas separation membrane applications. Besides, due to the considerable reactivity of the epoxide group of Elvaloy4170, it tends to take part in chemical reactions and form covalent bond with functionalized groups to construct more efficient MMMs. (M.R. Omidkhah). terized by Freeman . To overcome the Robeson's upper bound trade-off, inorganic membranes were proposed for gas separations . However, despite the excellent separation properties of the inorganic membranes, they are brittle and difficult to handle. Besides, their fabrication is expensive and cannot be transformed into a high surface area module easily . Consequently, researchers have improved separation properties of the existing polymers with embedding inorganic materials into the polymer matrix . These new class of membranes are called mixed matrix membranes (MMMs). MMMs combine the superior gas separation factor of the inorganic materials with the desirable mechanical properties and economical processing of polymers . Considerable studies showed that compared to the corresponding pure polymer membranes, MMMs have enhanced separation properties [1,19-22]. Different kinds of inorganic fillers such as zeolites [23,24], carbon molecular sieves (CMS) [14,15], activated carbon [25,26], supermolecular bucky balls carbon cages (fullerene, C 60 ) [27-29], metal oxides [1,20] and metal organic frameworks [30] have been used as the dispersed phase for the fabrication of MMMs. Sterescu et al. [27,29] fabricated the novel MMMs by the covalent coupling of C 60
Journal of Industrial and Engineering Chemistry, 2014
The Canadian Journal of Chemical Engineering, 2015
Journal of the Taiwan Institute of Chemical Engineers, 2015
Journal of Membrane Science, 2015
Journal of Natural Gas Science and Engineering, 2015
One of the safe and pressure relieving systems in oil and gas refineries as well as petrochemical... more One of the safe and pressure relieving systems in oil and gas refineries as well as petrochemical complexes, is the relief header with the flare stack being the last component. In this network all the excess gases are collected and sent to flare stack to be burnt. A great amount of these gas mixtures has a high heating value and in some cases it can even be used as the raw material for various units. It is clear that burning this gas mixture in flare stack causes environmental problems like air and noise pollution and also is a financial waste. In this paper a step by step approach and calculations are given to calculate and discuss flare gas recovery benefits for refineries. The method contains data gathering of flare line's composition and other conditions, simulating of data and calculate financial benefits for the case study by available equations. Therefore, Tabriz oil refinery flaring system and available equation for flare system are used as a case study. Flare gas mixtur...
The role of the feed analysis in the basic design engineering contract is studied in this article.
In this work, the cross-linked poly (vinyl alcohol)/formaldehyde with different blend composition... more In this work, the cross-linked poly (vinyl alcohol)/formaldehyde with different blend compositions (FA/PVA: 1, 3, 5 ratio%) were synthesized. In addition, different diethanolamine concentrations ranging from 15-45 wt % were investigated for membrane fabrication. Moreover, the membranes were characterized by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) and contact angle measurement. Furthermore, the effects of crosslinking agent content, amine concentration and feed pressure on CO2/CH4 transport properties were investigated in pure gas experiments. The results showed that CO2 and CH4 permeances decreased with increasing FA/PVA mass ratio, in comparison with uncross-linked membranes, although the selevtivities increased considerably. The highest selectivity (about 92.72) was achieved from PVA/FA(5wt%)/PTFE membrane. Moreover, it was found that CO2/CH4 selectivity was significantly decreased with increasing cross-linker/PVA mass ratio from 1 wt% to 5 wt%. On...
Iranian Polymer Journal
gas sweetening, facilitated transport membranes, gas separation, cross-linking, polyvinyl alcohol... more gas sweetening, facilitated transport membranes, gas separation, cross-linking, polyvinyl alcohol D eveloping new methods and technologies for CO 2 removal with a variety of applications, such as purification of synthesis gas, natural gas sweetening, and greenhouse gas sequestration are nowadays carried out in research works involving polymeric membranes. By employing suitable reactive carriers into the membrane matrix, the solubility and absorption rate of the reactive gas (i.e., CO 2 ) are enhanced. In facilitated transport membrane, the selective transport through the membrane occurs owing to a reversible reaction between the reactive carriers and the target gas, while in contrast the solution-diffusion is the dominant mechanism for permeation of inert gases such as CH 4 , N 2 and H 2 . In this work, the cross-linking of diethanolamine (DEA)-impregnated polyvinyl alcohol (PVA) by glutaraldehyde (GA) with different blend compositions (GA/PVA: 0.5, 1, 3, 5, 7 ratio%) were performed in the absence of an acid catalyst and organic solvents in order to avoid any interference in CO 2 facilitation reaction with DEA. The fabricated membranes were characterized by differential scanning calorimetry, Fourier transform infrared (FTIR) and scanning electron microscopy. Furthermore, the effects of cross-linking agent content and feed pressure on CO 2 /CH 4 transport properties were investigated in pure gas experiments. Finally, the cross-linked membranes showed reasonable CO 2 /CH 4 permselectivity indexes in comparison to uncross-linked membranes. The best-yield in CO 2 -selective membranes (DEA-PVA/GA (1 wt%)/PTFE) represented the best CO 2 /CH 4 selectivity of 91.13 for pure gas experiments.
International Journal of Greenhouse Gas Control, 2015
ABSTRACT
International Journal of Chemical Reactor Engineering, 2000
Ni/Al2O3 catalysts were synthesized by sol-gel method with various nickel loadings. Chemical and ... more Ni/Al2O3 catalysts were synthesized by sol-gel method with various nickel loadings. Chemical and physical properties of the catalysts were characterized by XRD and TPR techniques. X-ray diffraction patterns showed no peaks due to NiO species. Temperature-...
Despite the high energy demand in the industrialized world and the pollution problems caused by w... more Despite the high energy demand in the industrialized world and the pollution problems caused by widespread use of fossil fuels, the need for developing renewable energy sources with less environmental impacts are increasing. Biodiesel production is undergoing rapid and extensive technological reforms in industries and academia. The major obstacle in production and biodiesel commercialization path is production cost. Thus, in previous years numerous studies on the use of technologies and different methods to evaluate optimal conditions of biodiesel production technically and economically have been carried out. In this paper, a comparative review of the current technological methods so far used to produce biodiesel has been investigated. Four primary approaches to make biodiesel are direct use and blending of vegetable oils, micro-emulsions, thermal cracking (pyrolysis) and transesterification. Transesterification reaction, the most common method in the production of biodiesel, is emphasized in this review. The two types of transestrification process; catalytic and non-catalytic are discussed at length in the paper. Both advantages and disadvantages of the different biodiesel production methods are also discussed.
RSC Adv., 2015
ABSTRACT Olefins and paraffins are the main building blocks for many products in the petrochemica... more ABSTRACT Olefins and paraffins are the main building blocks for many products in the petrochemical industry. Various research studies have demonstrated the viability of polyimide membranes for high performance olefin/paraffin separation. Further advancements in this field require having a thorough understanding of both sorptive and diffusive factors of permeation. This research study presents an extensive analysis on using frame of reference/bulk flow and Maxwell-Stefan models in order to elaborate on the transport and prediction of the performance in the case of propylene/propane separation using polyimide membranes. Sorption data of pure gases are utilized to calculate the sorption level of gases in binary mixture. The contributions of kinetic and thermodynamic coupling effects (TCE) are assessed using Maxwell-Stefan approach. Moreover, the dual-mode diffusion coefficients are evaluated and optimized for achieving higher accuracy predictions in the case of binary gas mixture. The results reveal the significant role of thermodynamic compared to kinetic coupling effects in governing the transport properties. In overall, Maxwell-Stephan model with the contribution of TCEs offers improved predictions compared to frame of reference/bulk flow model. The findings highlight the inevitable role of taking into account the prominent interactions of feed components in model development for better prediction of performance and evaluation of propylene/propane separation unit using polyimide membranes.
Greenhouse Gases: Science and Technology, 2015
ABSTRACT
Journal of the Taiwan Institute of Chemical Engineers, 2014
This is the first report of gas transport properties of polymer Elvaloy4170. Elvaloy4170 is a com... more This is the first report of gas transport properties of polymer Elvaloy4170. Elvaloy4170 is a commercially available polymer, which has very low price and good mechanical properties. In this work, mixed matrix membranes (MMMs) were fabricated by embedding the multi-walled carbon nanotubes (MWNTs) into El-valoy4170. Additionally, the effects of functionalization of the nanotubes with acid treatment and their loadings were evaluated on morphology and gas permeation properties of the membranes. The fabricated membranes were characterized by Raman spectroscopy, field emission scanning electron microscopy (FESEM) and differential scanning calorimeter (DSC). Moreover, the effects of filler loading and feed pressure (from 2 to 6 bar) on CO 2 /CH 4 transport properties were considered in pure gas experiment. The gas permeability results of Elvaloy4170 membrane revealed that with increasing the pressure from 2 to 6 bar, CO 2 permeability and CO 2 /CH 4 selectivity increased 30% and 14%, respectively. Furthermore, compared to neat membrane, the MMM with 1 wt.% of f-MWNTs increased CO 2 and CH 4 permeabilities by 30% and 40%, respectively. In addition, it was found that the CO 2 /CH 4 selectivity increased as the content of f-MWNTs increased from 1 wt.% to 4 wt.% in the polymer matrix. Finally, this study reveals that membranes fabricated from commercial polymer Elvaloy4170 were permeable and have the great potential to be applied for other gas separation membrane applications. Besides, due to the considerable reactivity of the epoxide group of Elvaloy4170, it tends to take part in chemical reactions and form covalent bond with functionalized groups to construct more efficient MMMs. (M.R. Omidkhah). terized by Freeman . To overcome the Robeson's upper bound trade-off, inorganic membranes were proposed for gas separations . However, despite the excellent separation properties of the inorganic membranes, they are brittle and difficult to handle. Besides, their fabrication is expensive and cannot be transformed into a high surface area module easily . Consequently, researchers have improved separation properties of the existing polymers with embedding inorganic materials into the polymer matrix . These new class of membranes are called mixed matrix membranes (MMMs). MMMs combine the superior gas separation factor of the inorganic materials with the desirable mechanical properties and economical processing of polymers . Considerable studies showed that compared to the corresponding pure polymer membranes, MMMs have enhanced separation properties [1,19-22]. Different kinds of inorganic fillers such as zeolites [23,24], carbon molecular sieves (CMS) [14,15], activated carbon [25,26], supermolecular bucky balls carbon cages (fullerene, C 60 ) [27-29], metal oxides [1,20] and metal organic frameworks [30] have been used as the dispersed phase for the fabrication of MMMs. Sterescu et al. [27,29] fabricated the novel MMMs by the covalent coupling of C 60
Journal of Industrial and Engineering Chemistry, 2014