The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Mohammad Reza Rahimpour - One of the best experts on this subject based on the ideXlab platform.
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Hydrogen Production through Thermal Decomposition of Hydrogen Sulfide: Modification of the Sulfur Recovery Unit To Produce Ultrapure Hydrogen
Industrial & Engineering Chemistry Research, 2018Co-Authors: Hossain Ghahraloud, Mohammad Farsi, Mohammad Reza RahimpourAbstract:The main goal of this research is modification of the Claus process to produce ultrapure hydrogen through hydrogen sulfide decomposition. The furnace and catalytic reactors in the Claus process are equipped with coil and hydrogen Perm-Selective Membrane tubes. In the proposed structure, hydrogen is produced in the coil furnace and separated from gas stream in the Membrane reactors. The conventional and proposed processes are modeled on the basis of the mass and energy balance equations at steady state condition. To prove the accuracy of developed model and considered assumptions, the simulation results of conventional process are compared with the available plant data. In addition, to achieve maximum sulfur recovery and hydrogen production, the optimal operating condition of the proposed process is calculated by considering operational and environmental constraints by the Genetic algorithm. On the basis of the simulation results, the rate of hydrogen production in the conventional and proposed furnaces ar...
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Green methanol synthesis process from carbon dioxide via reverse water gas shift reaction in a Membrane reactor
Chemical Engineering Research and Design, 2018Co-Authors: Fereshteh Samimi, Dornaz Karimipourfard, Mohammad Reza RahimpourAbstract:Abstract In the present work, carbon dioxide hydrogenation to methanol via reverse water gas shift reaction (CAMERE) in an industrial scale was modeled and optimized. In this process, syngas is first produced by CO2 hydrogenation through reverse water gas shift (RWGS) reaction over Ni/Al12O19 catalyst and next the syngas is conveyed to a reactor as the feedstock to produce methanol. The inner tubes of methanol synthesis reactor were coated by a water Perm-Selective Membrane for removal of H2O, as the cause of catalyst poisoning. A precise two-dimensional model solved by finite-difference procedure was employed to evaluate both RWGS and methanol synthesis Membrane reactors performance. Also, the operating conditions of the RWGS reactor were optimized by differential evolution (DE) technique to gain a maximum methanol production rate. Moreover, the results of the methanol production reactor from the CAMERE process were compared with the conventional route (CR) in which methanol is produced from coal and natural gas. In the case of methanol synthesis Membrane reactor, CAMERE process was superior to CR due to achieving 20.8% increase in methanol production rate. The results of this process modeling provide a good initial insight for green methanol production form indirect CO2 conversion.
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An environmentally friendly configuration for reduction of toxic products in a thermally coupled reactor of styrene and tri-reformer of methane
Journal of environmental chemical engineering, 2017Co-Authors: Ali Mirvakili, Hadiseh Khalilpourmeymandi, M. Heravi, Mohammad Reza RahimpourAbstract:Abstract The aim of this work is a comparison of different hydrogen permeation Membranes in a thermally coupled Membrane reactor in producing two precious chemicals, hydrogen and styrene. A thermally coupled Membrane reactor is designed as a double pipe reactor where methane tri-reforming for hydrogen production is considered in exothermic side of reactor and styrene production reaction takes place in endothermic side. The walls of the shell side are coated by the layers of hydrogen Perm-Selective Membrane. The produced hydrogen in the endothermic side is transferred to the permeation side, while the generated heat in the exothermic side is transferred to the endothermic section. The reactor performance is theoretically investigated in the presence of six types of hydrogen Perm-Selective Membranes which are stable at operating conditions. Results are compared with each other and it is concluded that the highest hydrogen permeation rate (maximum 0.6 mol/s) is achieved in VCr4Ti4 Membrane named as TCMR5. Therefore, it leads to the highest ethylbenzene conversion (98%) and styrene production yield (95%) in the endothermic side as well as methane conversion (98.5%) in the exothermic side. Furthermore, toxic materials such as benzene and toluene decrease to about 66% and 46% in TCMR5 rather than the conventional reactor. Consequently, the fifth thermally coupled Membrane reactor encoded TCMR5 is an environmentally friendly configuration than others.
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Simultaneous production of dimethyl ether (DME), methyl formate (MF) and hydrogen from methanol in an integrated thermally coupled Membrane reactor
Journal of Natural Gas Science and Engineering, 2015Co-Authors: Ali Bakhtyari, Mostafa Mohammadi, Mohammad Reza RahimpourAbstract:Abstract The present study aims to presents two new configurations to improve dimethyl ether (DME) production rate besides producing methyl formate (MF) and hydrogen. In this regard, a thermally coupled reactor (TCR) and an integrated thermally coupled Membrane reactor (TCMR) with feature of simultaneous production of DME, MF and hydrogen from methanol is proposed. A palladium–silver Membrane with high hydrogen permeation rate is utilized to boost hydrogen recovery and MF production rate in TCMR. A one-dimensional plug flow model is considered to evaluate molar and thermal performance of the proposed configurations. Effect of various operating conditions such as inlet flow rates and permeation side configurations on the temperature profiles, methanol conversion, and DME and hydrogen production rate is studied numerically. Utilizing TCR and TCMR configurations promotes methanol conversion to DME to %85 and %87, respectively. Besides, a %22 increase in methanol conversion in the endothermic side was observed applying the hydrogen Perm-Selective Membrane. Generally, higher methanol conversion in both endothermic and exothermic sides and hydrogen production rate in the permeation side was observed using a sweep gas with higher flow rates and lower temperature.
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Differential evolution (DE) strategy for optimization of methane steam reforming and hydrogenation of nitrobenzene in a hydrogen Perm-Selective Membrane thermally coupled reactor
International Journal of Energy Research, 2013Co-Authors: Mohammad Reza Rahimpour, Zahra Arab Aboosadi, A. H. JahanmiriAbstract:In this work, a thermally coupled Membrane reactor is proposed for methane steam reforming and hydrogenation of nitrobenzene. The steam reforming process is carried out in the assisted Membrane surface of the endothermic side, while the hydrogenation reaction of nitrobenzene to aniline is carried out on the other Membrane surface of the exothermic side. The differential evolution (DE) strategy is applied to optimize this reactor considering nitrobenzene and methane conversion as the main objectives. The co-current mode is investigated in this study, and the achieved optimization results are compared with those of conventional steam reformer reactor operated under the same feed conditions. The optimum values of feed temperature of exothermic side, feed molar flow rate of nitrobenzene, the steam-to-nitrobenzene molar ratio and the hydrogen-to-nitrobenzene molar ratio are determined during the optimization process. The simulation results show that the methane conversion and consequently hydrogen recovery yield are increased by 39.3% and 1.57, respectively, which contribute to aniline production with 27.3% saving in hydrogen supply from external and a reduction in environmental problems due to 100% nitrobenzene conversion. The optimization results justify the feasibility of coupling these reactions. Experimental proof-of-concept is needed to establish the validity and safe operation of the novel reactor. © 2012 John Wiley & Sons, Ltd.
Guomin Cui - One of the best experts on this subject based on the ideXlab platform.
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development of a novel flowsheet for sulfur iodine cycle based on the electrochemical bunsen reaction for hydrogen production
International Journal of Hydrogen Energy, 2017Co-Authors: Zhi Ying, Xiaoyuan Zheng, Yao Zhang, Guomin CuiAbstract:Abstract The sulfur–iodine (SI) cycle is one of the promising methods for large-scale hydrogen production. A new flowsheet of SI cycle assembled with electrochemical Bunsen reaction was devised and modeled in this work. Adoption of electrochemical Bunsen reaction simplifies the flowsheet. The high concentrations of H2SO4 and HI, especially the over-azeotropic HI solution, successfully generated in the separated compartments of electrochemical cell without requiring further separation and purification. The enriched HI gas evaporates through flash, eliminating the extra concentration process, and then decomposes into 1 mol/s of H2 in hydrogen Perm-Selective Membrane reactor. A HI separator is employed to maximize the recycle of undecomposed HI. The concentrated H2SO4 after flash decomposes into 0.5 mol/s of O2. The mass and energy balances of the SI cycle were evaluated. The cascade utilization of energy was carried out through internal heat exchange between hot and cold streams in the flowsheet. The surplus waste heat was recovered as electric power to improve the energy utilization efficiency. The overall thermal efficiency of the flowsheet was estimated to be 42–50% and was sensitive to heat recovery ratio. The simplified and energy-efficient flowsheet is competitive to the previous traditional flowsheets and will provide a reference for the industrial utilization of SI cycle.
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Development of a novel flowsheet for sulfur–iodine cycle based on the electrochemical Bunsen reaction for hydrogen production
International Journal of Hydrogen Energy, 2017Co-Authors: Zhi Ying, Xiaoyuan Zheng, Yao Zhang, Guomin CuiAbstract:The sulfur–iodine (SI) cycle is one of the promising methods for large-scale hydrogen production. A new flowsheet of SI cycle assembled with electrochemical Bunsen reaction was devised and modeled in this work. Adoption of electrochemical Bunsen reaction simplifies the flowsheet. The high concentrations of H2SO4and HI, especially the over-azeotropic HI solution, successfully generated in the separated compartments of electrochemical cell without requiring further separation and purification. The enriched HI gas evaporates through flash, eliminating the extra concentration process, and then decomposes into 1 mol/s of H2in hydrogen Perm-Selective Membrane reactor. A HI separator is employed to maximize the recycle of undecomposed HI. The concentrated H2SO4after flash decomposes into 0.5 mol/s of O2. The mass and energy balances of the SI cycle were evaluated. The cascade utilization of energy was carried out through internal heat exchange between hot and cold streams in the flowsheet. The surplus waste heat was recovered as electric power to improve the energy utilization efficiency. The overall thermal efficiency of the flowsheet was estimated to be 42–50% and was sensitive to heat recovery ratio. The simplified and energy-efficient flowsheet is competitive to the previous traditional flowsheets and will provide a reference for the industrial utilization of SI cycle.
Ali M. Bahmanpour - One of the best experts on this subject based on the ideXlab platform.
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The aromatic enhancement in the axial‐flow spherical packed‐bed Membrane naphtha reformers in the presence of catalyst deactivation
AIChE Journal, 2011Co-Authors: Mohammad Reza Rahimpour, K. Paymooni, Davood Iranshahi, E. Pourazadi, Ali M. BahmanpourAbstract:Because of some disadvantages of conventional tubular reactors (CTRs), the concept of spherical Membrane reactors is proposed as an alternative. In this study, it is suggested to apply hydrogen Perm-Selective Membrane in the axial-flow spherical packed-bed naphtha reformers. The axial flow spherical packed-bed Membrane reactor (AF-SPBMR) consists of two concentric spheres. The inner sphere is supposed to be a composite wall coated by a thin Pd-Ag Membrane layer. Set of coupled partial differential equations are developed for the AF-SPBMR model considering the catalyst deactivation, which are solved by using orthogonal collocation method. Differential evolution optimization technique identifies some decision variables which can manipulate the input parameters to obtain the desired results. In addition to lower pressure drop, the enhancement of aromatics yield by the Membrane layer in AF-SPBMR adds additional superiority to the spherical reactor performance in comparison with CTR. © 2011 American Institute of Chemical Engineers AIChE J, 2011
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Optimization of hydrogen production via coupling of the Fischer–Tropsch synthesis reaction and dehydrogenation of cyclohexane in GTL technology
Applied Energy, 2011Co-Authors: Mohammad Reza Rahimpour, Ali M. BahmanpourAbstract:Abstract In this study, a thermally-coupled reactor containing the Fischer–Tropsch synthesis reaction in the exothermic side and dehydrogenation of cyclohexane in the endothermic side has been modified using a hydrogen Perm-Selective Membrane as the shell of the reactor to separate the produced hydrogen from the dehydrogenation process. Permeated hydrogen enters another section called permeation side to be collected by Argon, known as the sweep gas. This three-sided reactor has been optimized using differential evolution (DE) method to predict the conditions at which the reactants’ conversion and also the hydrogen recovery yield would be maximized. Minimizing the CO2 and CH4 yield in the reactor’s outlet as undesired products is also considered in the optimization process. To reach this goal, optimal initial molar flow rate and inlet temperature of three sides as well as pressure of the exothermic side have been calculated. The obtained results have been compared with the conventional reactor data of the Research Institute of Petroleum Industry (RIPI), the Membrane dual – type reactor suggested for Fischer–Tropsch synthesis, and the Membrane coupled reactor presented for methanol synthesis. The comparison shows acceptable enhancement in the reactor’s performance and that the production of hydrogen as a valuable byproduct should also be considered.
K. Paymooni - One of the best experts on this subject based on the ideXlab platform.
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A comparative study between a fluidized-bed and a fixed-bed water Perm-Selective Membrane reactor with in situ H2O removal for Fischer–Tropsch synthesis of GTL technology
Journal of Natural Gas Science and Engineering, 2011Co-Authors: Mohammad Reza Rahimpour, A. Mirvakili, K. Paymooni, Behdad MoghtaderiAbstract:Abstract In order to eliminate the pressure drop problem and mal distribution of the temperature profile along the reactors, fluidized-bed Membrane reactors are proposed as an alternative for Fischer–Tropsch synthesis (FTS) in gas-to-liquid (GTL) technology. Regarding this, a novel cascading fluidized-bed Membrane reactor (CFMR) is proposed in this study and compared with a fixed-bed Membrane cascading with fluidized-bed Membrane reactor (FMFMR). The CFMR configuration consists of a fluidized-bed water Perm-Selective Membrane reactor followed by a fluidized-bed hydrogen Perm-Selective Membrane reactor. The performance of CFMR is compared with FMFMR in order to investigate the effect of fluidization concept on the reactor performance. Unlike CFMR where a fluidized-bed concept is applied in the first reactor, a fixed-bed concept is used in the first reactor of FMFMR. The modeling results show 5.3% increase in the gasoline yield and 12% decrease in CO 2 yield in CFMR in comparison with FMFMR owing to applying a fluidized-bed concept instead of a fixed-bed concept in which more effective temperature management is achieved. According to the modeling results, CFMR is superior to FMFMR for FTS in GTL technology owing to achieving excellent temperature control and a small pressure drop and consequently higher gasoline yield and lower CO 2 yield.
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The aromatic enhancement in the axial‐flow spherical packed‐bed Membrane naphtha reformers in the presence of catalyst deactivation
AIChE Journal, 2011Co-Authors: Mohammad Reza Rahimpour, K. Paymooni, Davood Iranshahi, E. Pourazadi, Ali M. BahmanpourAbstract:Because of some disadvantages of conventional tubular reactors (CTRs), the concept of spherical Membrane reactors is proposed as an alternative. In this study, it is suggested to apply hydrogen Perm-Selective Membrane in the axial-flow spherical packed-bed naphtha reformers. The axial flow spherical packed-bed Membrane reactor (AF-SPBMR) consists of two concentric spheres. The inner sphere is supposed to be a composite wall coated by a thin Pd-Ag Membrane layer. Set of coupled partial differential equations are developed for the AF-SPBMR model considering the catalyst deactivation, which are solved by using orthogonal collocation method. Differential evolution optimization technique identifies some decision variables which can manipulate the input parameters to obtain the desired results. In addition to lower pressure drop, the enhancement of aromatics yield by the Membrane layer in AF-SPBMR adds additional superiority to the spherical reactor performance in comparison with CTR. © 2011 American Institute of Chemical Engineers AIChE J, 2011
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A novel water Perm-Selective Membrane dual-type reactor concept for Fischer–Tropsch synthesis of GTL (gas to liquid) technology
Energy, 2011Co-Authors: Mohammad Reza Rahimpour, A. Mirvakili, K. PaymooniAbstract:The present study proposes a novel configuration of Fischer–Tropsch synthesis (FTS) reactors in which a fixed-bed water Perm-Selective Membrane reactor is followed by a fluidized-bed hydrogen Perm-Selective Membrane reactor. This novel concept which has been named fixed-bed Membrane reactor followed by fluidized-bed Membrane reactor (FMFMDR) produces gasoline from synthesis gas. The walls of the tubes of a fixed-bed reactor (water-cooled reactor) of FMFMDR configuration are coated by a high water Perm-Selective Membrane layer. In this new configuration, two Membrane reactors instead of one Membrane reactor are developed for FTS reactions. In other words, two different Membrane layers are used. In order to investigate the performance of FMFMDR, a one-dimensional heterogeneous model is taken into consideration. The simulation results of three schemes named fluidized-bed Membrane dual-type reactor (FMDR), FMFMDR and conventional fixed-bed reactor (CR) are presented. They have been compared in terms of temperature, gasoline and CO2 yields, H2 and CO conversions and the water permeation rate through the Membrane layer. Results show that the gasoline yield in FMFMDR is higher than the one in FMDR. The FMFMDR configuration not only decreases the undesired product such as CO2 but also produces more gasoline.
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a novel water perm selective Membrane dual type reactor concept for fischer tropsch synthesis of gtl gas to liquid technology
Energy, 2011Co-Authors: M R Rahimpour, A. Mirvakili, K. PaymooniAbstract:Abstract The present study proposes a novel configuration of Fischer–Tropsch synthesis (FTS) reactors in which a fixed-bed water Perm-Selective Membrane reactor is followed by a fluidized-bed hydrogen Perm-Selective Membrane reactor. This novel concept which has been named fixed-bed Membrane reactor followed by fluidized-bed Membrane reactor (FMFMDR) produces gasoline from synthesis gas. The walls of the tubes of a fixed-bed reactor (water-cooled reactor) of FMFMDR configuration are coated by a high water Perm-Selective Membrane layer. In this new configuration, two Membrane reactors instead of one Membrane reactor are developed for FTS reactions. In other words, two different Membrane layers are used. In order to investigate the performance of FMFMDR, a one-dimensional heterogeneous model is taken into consideration. The simulation results of three schemes named fluidized-bed Membrane dual-type reactor (FMDR), FMFMDR and conventional fixed-bed reactor (CR) are presented. They have been compared in terms of temperature, gasoline and CO 2 yields, H 2 and CO conversions and the water permeation rate through the Membrane layer. Results show that the gasoline yield in FMFMDR is higher than the one in FMDR. The FMFMDR configuration not only decreases the undesired product such as CO 2 but also produces more gasoline.
Abdolhossein Jahanmiri - One of the best experts on this subject based on the ideXlab platform.
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Synthesis gas production in a novel hydrogen and oxygen Perm-Selective Membranes tri-reformer for methanol production
Journal of Natural Gas Science and Engineering, 2012Co-Authors: Mohammad Reza Rahimpour, Z. Arab Aboosadi, Abdolhossein JahanmiriAbstract:Abstract Tri-reforming is a synergetic combination of carbon dioxide reforming, steam reforming and partial oxidation of methane in a single unit for effective production of synthesis gas. In this study, a novel multi-tubular fixed bed tri-reformer assisted with hydrogen and oxygen Perm-Selective Membranes is proposed for synthesis gas production for methanol synthesis reactor. This reactor can be used instead of conventional steam methane reformer (SMR) and conventional auto-thermal reformer (ATR). A distributed mathematical model is developed for tri-reformer Membrane reactor which consists of three sides for synthesis gas production. Air is fed co-currently into the oxygen Perm-Selective Membrane in the inner tube and oxygen permeates into the reaction side for oxidative reforming of methane. Selective permeation of hydrogen via the Pd-based Membrane is achieved by co-current flow of sweeping gas through the permeation side. The results of tri-reformer are compared with the corresponding predicted results by HYSIS simulation software under the same feed condition. The superiorities of this novel configuration to optimized tri-reformer without any Membrane (Arab Aboosadi, Z., Jahanmiri, A.H., Rahimpour, M.R., 2011. Optimization of tri-reformer reactor to produce synthesis gas for methanol production using differential evolution (DE) method. Appl. Energy. 88, 2691–2701) are in-situ oxygen production (44.7% saving in supplying oxygen from external), high methane conversion and hydrogen yield at lower reactant input temperature and reduction of hot spot temperature in the catalytic bed.
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Enhancement of methanol synthesis in a Water vapor-perm selective Membrane reactor
2011Co-Authors: Mohammad Farsi, Abdolhossein JahanmiriAbstract:In this work a Membrane reactor is proposed for water vapor removal from reaction zone in the methanol production process to overcome thermodynamic equilibrium limitations of the methanol synthesis reactions. A steady state heterogeneous one-dimensional mathematical model is developed for simulation of the proposed catalytic fixed bed Membrane reactor. To verify the accuracy of the considered model and assumptions, simulation results of the conventional reactor is compared with the available industrial plant data. The Membrane reactor benefits are the higher methanol production rate, higher quality of outlet product and consequently lower cost in the product purification stage. This configuration has enhanced the methanol yield about 5.7% than industrial reactor. Experimental proof-of-concept is needed to establish the safe operation of the proposed configuration.