The Experts below are selected from a list of 3984 Experts worldwide ranked by ideXlab platform
Thomas A Adams - One of the best experts on this subject based on the ideXlab platform.
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dynamic analysis and open loop start up of an integrated radiant syngas cooler and Steam Methane Reformer
Aiche Journal, 2017Co-Authors: Jaffer H Ghouse, Dominik Seepersad, Thomas A AdamsAbstract:The transient performance of an integrated radiant syngas cooler (RSC) of an entrained-bed gasifier and Steam Methane Reformer (SMR) is investigated. Base-case designs using either co-current or counter-current configurations are subjected to operating transients to evaluate the feasibility to transition to new steady states. Each system, under open loop, is subjected to changes in key variables of the SMR feed on the tube side and disturbances to variables of the coal-derived syngas on the RSC side to determine the dynamics and stability of the integrated system. The results indicate that the co-current configuration is flexible to move to new operating steady states and more safe than the counter-current configuration, although it provides less cooling and has poorer Methane conversion. The variables likely to violate the design limit in the event of a disturbance are identified. A start-up procedure is also established based on industrial practices employed for entrained-bed gasifiers and Methane Reformers. © 2017 American Institute of Chemical Engineers AIChE J, 2017
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optimal design of an integrated radiant syngas cooler and Steam Methane Reformer using nlp and meta heuristic algorithms
Computer-aided chemical engineering, 2016Co-Authors: Jaffer H Ghouse, Thomas A AdamsAbstract:Abstract In this study, optimal designs for a novel integrated radiant syngas cooler and Steam Methane Reformer are explored. Previously, feasible base-case designs were established but were sub-optimal given the complexity of the model that included more than 200,000 equations. The two optimization approaches used in this study include: (i) conventional non-linear programming solvers (within gPROMS) and (ii) meta-heuristic techniques (Differential Evolution and Particle Swarm Optimization). The model for the integrated device was implemented in gPROMS, and hence the built-in NLP solver was used. However, the NLP solver can only guarantee local optimality, and finding good initial guesses manually can be prohibitively time consuming. Therefore, the results were compared with meta-heuristic methods that are easy to implement, are parallelizable and can cover a wide search space. The results using both methods showed significant improvement in capital cost, as much as 40% and with improved Methane conversion. The advantage of parallel computing when using meta-heuristic techniques for optimizing multi-scale models was clear: for example, the CPU time reduced by up to 50% when twice the number of cores was utilised to simulate the multi-scale model in gPROMS.
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modelling simulation and design of an integrated radiant syngas cooler and Steam Methane Reformer for use with coal gasification
Fuel Processing Technology, 2015Co-Authors: Jaffer H Ghouse, Dominik Seepersad, Thomas A AdamsAbstract:Abstract In this work, a novel process intensification design is proposed to integrate the Radiant Syngas Cooler (RSC) utilised to cool the coal-derived synthesis gas in entrained-bed gasifiers and a Steam Methane Reformer (SMR). The feasibility of the proposed integrated system is analyzed by developing a rigorous, dynamic, multi-dimensional model and establishing design heuristics for the integrated system. Two different flow configurations are explored; co-current and counter-current. The simulation results show that the proposed concept is feasible that allows for Methane conversions as high as 80% in co-current mode and 88% in counter-current mode. The results also demonstrate that the counter-current design, though with higher conversion and cooling duty provided when compared to co-current designs, is limited by the tube wall material limitations. Our analysis shows that the total avoided CO 2 emissions is 13.3 tonnes/h by using the proposed integrated configuration in place of an external Reformer for the natural gas feed rates considered in this study. In addition, a sensitivity analysis is performed on key model assumptions and the resulting effect on the performance is assessed. The sensitivity results have helped identify key factors to consider prior to pilot-scale implementation and further improvement for agile designs; a one third reduction in tube length reduced pressure drop by as much as 50% but reduces Methane conversion by 15% points, neglecting slag deposition on tubes over-predicts performance only by 3%, and a 10% change in gas emissivity calculations affects model prediction of performance by less than 1%.
Jaffer H Ghouse - One of the best experts on this subject based on the ideXlab platform.
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dynamic analysis and open loop start up of an integrated radiant syngas cooler and Steam Methane Reformer
Aiche Journal, 2017Co-Authors: Jaffer H Ghouse, Dominik Seepersad, Thomas A AdamsAbstract:The transient performance of an integrated radiant syngas cooler (RSC) of an entrained-bed gasifier and Steam Methane Reformer (SMR) is investigated. Base-case designs using either co-current or counter-current configurations are subjected to operating transients to evaluate the feasibility to transition to new steady states. Each system, under open loop, is subjected to changes in key variables of the SMR feed on the tube side and disturbances to variables of the coal-derived syngas on the RSC side to determine the dynamics and stability of the integrated system. The results indicate that the co-current configuration is flexible to move to new operating steady states and more safe than the counter-current configuration, although it provides less cooling and has poorer Methane conversion. The variables likely to violate the design limit in the event of a disturbance are identified. A start-up procedure is also established based on industrial practices employed for entrained-bed gasifiers and Methane Reformers. © 2017 American Institute of Chemical Engineers AIChE J, 2017
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optimal design of an integrated radiant syngas cooler and Steam Methane Reformer using nlp and meta heuristic algorithms
Computer-aided chemical engineering, 2016Co-Authors: Jaffer H Ghouse, Thomas A AdamsAbstract:Abstract In this study, optimal designs for a novel integrated radiant syngas cooler and Steam Methane Reformer are explored. Previously, feasible base-case designs were established but were sub-optimal given the complexity of the model that included more than 200,000 equations. The two optimization approaches used in this study include: (i) conventional non-linear programming solvers (within gPROMS) and (ii) meta-heuristic techniques (Differential Evolution and Particle Swarm Optimization). The model for the integrated device was implemented in gPROMS, and hence the built-in NLP solver was used. However, the NLP solver can only guarantee local optimality, and finding good initial guesses manually can be prohibitively time consuming. Therefore, the results were compared with meta-heuristic methods that are easy to implement, are parallelizable and can cover a wide search space. The results using both methods showed significant improvement in capital cost, as much as 40% and with improved Methane conversion. The advantage of parallel computing when using meta-heuristic techniques for optimizing multi-scale models was clear: for example, the CPU time reduced by up to 50% when twice the number of cores was utilised to simulate the multi-scale model in gPROMS.
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modelling simulation and design of an integrated radiant syngas cooler and Steam Methane Reformer for use with coal gasification
Fuel Processing Technology, 2015Co-Authors: Jaffer H Ghouse, Dominik Seepersad, Thomas A AdamsAbstract:Abstract In this work, a novel process intensification design is proposed to integrate the Radiant Syngas Cooler (RSC) utilised to cool the coal-derived synthesis gas in entrained-bed gasifiers and a Steam Methane Reformer (SMR). The feasibility of the proposed integrated system is analyzed by developing a rigorous, dynamic, multi-dimensional model and establishing design heuristics for the integrated system. Two different flow configurations are explored; co-current and counter-current. The simulation results show that the proposed concept is feasible that allows for Methane conversions as high as 80% in co-current mode and 88% in counter-current mode. The results also demonstrate that the counter-current design, though with higher conversion and cooling duty provided when compared to co-current designs, is limited by the tube wall material limitations. Our analysis shows that the total avoided CO 2 emissions is 13.3 tonnes/h by using the proposed integrated configuration in place of an external Reformer for the natural gas feed rates considered in this study. In addition, a sensitivity analysis is performed on key model assumptions and the resulting effect on the performance is assessed. The sensitivity results have helped identify key factors to consider prior to pilot-scale implementation and further improvement for agile designs; a one third reduction in tube length reduced pressure drop by as much as 50% but reduces Methane conversion by 15% points, neglecting slag deposition on tubes over-predicts performance only by 3%, and a 10% change in gas emissivity calculations affects model prediction of performance by less than 1%.
Said Abboudi - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of catalytic coated walls of an indirect internal reforming solid oxide fuel cell influence of catalyst coating distribution on the Reformer efficiency
Energy Conversion and Management, 2018Co-Authors: Abdelhakim Settar, Nadhir Lebaal, Said AbboudiAbstract:Abstract In this research, the performance evaluation of Methane (CH4) Steam reforming in Wall Steam-Methane Reformer (WCR), intended to supply hydrogen (H2) to SOFC, is investigated using homemade code based on 2D numerical modeling. Focus is on the design of the catalyst coating on the walls of reactor. Various designs of nickel-based catalyst coating were closely examined and compared purporting to understand their effect on the WCR efficiency. The WCR designs operate at similar industrial operating conditions and with the same catalyst density. The computations were discussed with respect to the possible improvement on WCR efficiency. Comparing to the worst catalyst design found, the CH4 conversion rate improving is estimated to 31%, which corresponds to 95.8% more in H2 production. The obtained results are of practical importance for the design of the catalyst coating and saving fuel energy.
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Estimation of transient heat flux density during the heat supply of a catalytic wall Steam Methane Reformer
Heat and Mass Transfer, 2018Co-Authors: Abdelhakim Settar, Said Abboudi, Brahim Madani, Rachid NebbaliAbstract:Due to the endothermic nature of the Steam Methane reforming reaction, the process is often limited by the heat transfer behavior in the reactors. Poor thermal behavior sometimes leads to slow reaction kinetics, which is characterized by the presence of cold spots in the catalytic zones. Within this framework, the present work consists on a numerical investigation, in conjunction with an experimental one, on the one-dimensional heat transfer phenomenon during the heat supply of a catalytic-wall reactor, which is designed for hydrogen production. The studied reactor is inserted in an electric furnace where the heat requirement of the endothermic reaction is supplied by electric heating system. During the heat supply, an unknown heat flux density, received by the reactive flow, is estimated using inverse methods. In the basis of the catalytic-wall reactor model, an experimental setup is engineered in situ to measure the temperature distribution. Then after, the measurements are injected in the numerical heat flux estimation procedure, which is based on the Function Specification Method (FSM). The measured and estimated temperatures are confronted and the heat flux density which crosses the reactor wall is determined.
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Effect of inert metal foam matrices on hydrogen production intensification of Methane Steam reforming process in wall-coated Reformer
International Journal of Hydrogen Energy, 2018Co-Authors: Abdelhakim Settar, Said Abboudi, Nadhir LebaalAbstract:Numerical modeling of a heated mixture of Methane with Steam in 2D plane Wall-Coated Steam Methane Reformer (WC-SMR) with surface catalytic reaction at industrial conditions has been performed. The modeling was performed within the framework of Navier-Stokes equations for a laminar flow of a multi-component compressible gas. The influence of the insertion of non-catalytic nickel-based metal foam matrices in the catalytic zone of the WC-SMR on the hydrodynamic, thermal and mass behaviors of the gas mixture and its distribution along the reactor have been investigated. Three different Metal Foam (MF) samples have been investigated and then compared: Ni-Foam, Ni-Cr-Foam and Ni-Fe-Cr-Foam. It has been shown that not only the use of metal foam matrices but also their thermo-physical properties are important to improving the WC-SMR efficiency. It is demonstrated that such material can bring a significant enhancement for hydrogen production, heat and mass transfer processes. 16.91% of improvement in terms of H2 production is realized.
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Effect of inter-catalytic layer spacing at wall-coated Steam Methane Reformer surfaces on hydrogen production
2018 9th International Renewable Energy Congress (IREC), 2018Co-Authors: Abdelhakim Settar, Said Abboudi, Nadhir Lebaal, Rachid Nebbali, Brahim MadaniAbstract:This work deals with a numerical study on a wall-coated Steam Methane Reformer improvement. The effect of the catalytic layers configuration on the Methane conversion is analyzed. Two configurations of the catalyst region are compared. A catalytic region with parallel continuous layers, impregnated on both upper and lower walls, against a catalyst region endowed with an inter-catalytic layer spacing. The involved transport phenomena are governed by momentum, energy and species equations. The Navier-Stokes equations are employed in the mixture phase. The obtained results show that the utilization of discrete catalytic layers allows avoiding the cold zones on the catalytic region and enhancing the Methane conversion of the wall-coated Steam Methane Reformer.
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Numerical study on the effects of the macropatterned active surfaces on the wall-coated Steam Methane Reformer performances
International Journal of Hydrogen Energy, 2017Co-Authors: Abdelhakim Settar, Rachid Nebbali, Brahim Madani, Said AbboudiAbstract:Abstract This paper deals with a numerical study on the Steam Methane reforming reaction performances into a wall-coated Steam Methane Reformer (WC-SMR), intended to produce hydrogen. In this work a new catalytic pattern, purporting to enhance the WC-SMR efficiency, is proposed. A comparison study is made between the new inter-catalytic layers pattern and a conventional one with a continuous catalytic layer pattern. Both WC-SMR models operate at similar conditions and at the same design parameters, except the catalytic zone length which is monitored by taking into account the inter-catalytic layers spacing or not. Our results show that, by adopting a catalytic surface with an inter-catalytic spacing, the Methane conversion could be enhanced and thus the hydrogen production is intensified.
Abdelhakim Settar - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of catalytic coated walls of an indirect internal reforming solid oxide fuel cell influence of catalyst coating distribution on the Reformer efficiency
Energy Conversion and Management, 2018Co-Authors: Abdelhakim Settar, Nadhir Lebaal, Said AbboudiAbstract:Abstract In this research, the performance evaluation of Methane (CH4) Steam reforming in Wall Steam-Methane Reformer (WCR), intended to supply hydrogen (H2) to SOFC, is investigated using homemade code based on 2D numerical modeling. Focus is on the design of the catalyst coating on the walls of reactor. Various designs of nickel-based catalyst coating were closely examined and compared purporting to understand their effect on the WCR efficiency. The WCR designs operate at similar industrial operating conditions and with the same catalyst density. The computations were discussed with respect to the possible improvement on WCR efficiency. Comparing to the worst catalyst design found, the CH4 conversion rate improving is estimated to 31%, which corresponds to 95.8% more in H2 production. The obtained results are of practical importance for the design of the catalyst coating and saving fuel energy.
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Estimation of transient heat flux density during the heat supply of a catalytic wall Steam Methane Reformer
Heat and Mass Transfer, 2018Co-Authors: Abdelhakim Settar, Said Abboudi, Brahim Madani, Rachid NebbaliAbstract:Due to the endothermic nature of the Steam Methane reforming reaction, the process is often limited by the heat transfer behavior in the reactors. Poor thermal behavior sometimes leads to slow reaction kinetics, which is characterized by the presence of cold spots in the catalytic zones. Within this framework, the present work consists on a numerical investigation, in conjunction with an experimental one, on the one-dimensional heat transfer phenomenon during the heat supply of a catalytic-wall reactor, which is designed for hydrogen production. The studied reactor is inserted in an electric furnace where the heat requirement of the endothermic reaction is supplied by electric heating system. During the heat supply, an unknown heat flux density, received by the reactive flow, is estimated using inverse methods. In the basis of the catalytic-wall reactor model, an experimental setup is engineered in situ to measure the temperature distribution. Then after, the measurements are injected in the numerical heat flux estimation procedure, which is based on the Function Specification Method (FSM). The measured and estimated temperatures are confronted and the heat flux density which crosses the reactor wall is determined.
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Effect of inert metal foam matrices on hydrogen production intensification of Methane Steam reforming process in wall-coated Reformer
International Journal of Hydrogen Energy, 2018Co-Authors: Abdelhakim Settar, Said Abboudi, Nadhir LebaalAbstract:Numerical modeling of a heated mixture of Methane with Steam in 2D plane Wall-Coated Steam Methane Reformer (WC-SMR) with surface catalytic reaction at industrial conditions has been performed. The modeling was performed within the framework of Navier-Stokes equations for a laminar flow of a multi-component compressible gas. The influence of the insertion of non-catalytic nickel-based metal foam matrices in the catalytic zone of the WC-SMR on the hydrodynamic, thermal and mass behaviors of the gas mixture and its distribution along the reactor have been investigated. Three different Metal Foam (MF) samples have been investigated and then compared: Ni-Foam, Ni-Cr-Foam and Ni-Fe-Cr-Foam. It has been shown that not only the use of metal foam matrices but also their thermo-physical properties are important to improving the WC-SMR efficiency. It is demonstrated that such material can bring a significant enhancement for hydrogen production, heat and mass transfer processes. 16.91% of improvement in terms of H2 production is realized.
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Effect of inter-catalytic layer spacing at wall-coated Steam Methane Reformer surfaces on hydrogen production
2018 9th International Renewable Energy Congress (IREC), 2018Co-Authors: Abdelhakim Settar, Said Abboudi, Nadhir Lebaal, Rachid Nebbali, Brahim MadaniAbstract:This work deals with a numerical study on a wall-coated Steam Methane Reformer improvement. The effect of the catalytic layers configuration on the Methane conversion is analyzed. Two configurations of the catalyst region are compared. A catalytic region with parallel continuous layers, impregnated on both upper and lower walls, against a catalyst region endowed with an inter-catalytic layer spacing. The involved transport phenomena are governed by momentum, energy and species equations. The Navier-Stokes equations are employed in the mixture phase. The obtained results show that the utilization of discrete catalytic layers allows avoiding the cold zones on the catalytic region and enhancing the Methane conversion of the wall-coated Steam Methane Reformer.
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Numerical study on the effects of the macropatterned active surfaces on the wall-coated Steam Methane Reformer performances
International Journal of Hydrogen Energy, 2017Co-Authors: Abdelhakim Settar, Rachid Nebbali, Brahim Madani, Said AbboudiAbstract:Abstract This paper deals with a numerical study on the Steam Methane reforming reaction performances into a wall-coated Steam Methane Reformer (WC-SMR), intended to produce hydrogen. In this work a new catalytic pattern, purporting to enhance the WC-SMR efficiency, is proposed. A comparison study is made between the new inter-catalytic layers pattern and a conventional one with a continuous catalytic layer pattern. Both WC-SMR models operate at similar conditions and at the same design parameters, except the catalytic zone length which is monitored by taking into account the inter-catalytic layers spacing or not. Our results show that, by adopting a catalytic surface with an inter-catalytic spacing, the Methane conversion could be enhanced and thus the hydrogen production is intensified.
Thomas F Edgar - One of the best experts on this subject based on the ideXlab platform.
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a physics based model for industrial Steam Methane Reformer optimization with non uniform temperature field
Computers & Chemical Engineering, 2017Co-Authors: Ankur Kumar, Michael Baldea, Thomas F EdgarAbstract:Abstract In an industrial hydrogen production facility, Steam-Methane reforming reactions take place inside hundreds of catalyst-filled tubes placed in a large scale, high temperature furnace. Process efficiency depends strongly on the wall temperature distribution of the ensemble of Reformer tubes; a narrower distribution has a process intensification effect, by providing similar processing experience to every feedstock molecule. Such process intensification efforts require a furnace model that can predict the temperature distribution as a function of operating conditions. Currently available furnace modeling solutions are either computationally intensive, making them unsuitable for (online) optimization calculations, or empirical, having limited accuracy when wide changes in operating conditions are required. In this work, a physics-based furnace model is presented that overcomes these limitations. Empirical perturbations in a Hottel zone radiation model are proposed to capture the spatially non-symmetrical temperature distribution. The low computational time makes the model suitable for operational intensification based on reduction of temperature distribution non-uniformity.
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Multi-resolution model of an industrial hydrogen plant for plantwide operational optimization with non-uniform Steam-Methane Reformer temperature field
Computers and Chemical Engineering, 2017Co-Authors: Ankur Kumar, Thomas F Edgar, Michael BaldeaAbstract:Hydrogen is consumed in large quantities in the chemical industry. The most common industrial process for hydrogen production is Steam-Methane reforming, which is carried out using an energy-intensive furnace. The plant energy efficiency depends strongly on the spatial temperature distribution within the furnace; the narrower the distribution, the higher the efficiency that can be achieved. However, currently available studies on plantwide optimization of hydrogen plants ignore this crucial aspect. Adequate resolution of the spatial temperature distribution is necessary to determine the furnace operating temperature, which, in turn, determines the plant efficiency. In this work, a multi-resolution model of a hydrogen plant is developed. It includes a high-resolution model of the furnace, and low-resolution models, adequate for the purpose of plantwide optimization, of other unit operations. The developed model is used to determine the optimal process conditions after furnace temperature homogenization as part of a plant start-up or setpoint changeover procedure.
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Real-time optimization of an industrial Steam-Methane Reformer under distributed sensing
Control Engineering Practice, 2016Co-Authors: Ankur Kumar, Michael Baldea, Thomas F EdgarAbstract:Abstract Industrial hydrogen production takes place in large-scale Steam Methane Reformer (SMR) units, whose energy efficiency depends on the interior spatial temperature distribution. In this paper, a control-relevant empirical reduced-order SMR model is presented that predicts the furnace temperature distribution based on fuel input to a group of burners. The model is calibrated using distributed temperature measurements from an array of infrared cameras. The model is employed to optimize in real-time the temperature distribution and increase the energy efficiency in an industrial furnace. Experimental results confirm that the proposed framework has excellent performance.
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Smart Manufacturing Approach for Efficient Operation of Industrial Steam-Methane Reformers
Industrial & Engineering Chemistry Research, 2015Co-Authors: Ankur Kumar, Thomas F Edgar, Michael Baldea, Ofodike A. EzekoyeAbstract:Steam Methane reforming is a mature and complex process extensively used worldwide for hydrogen production from Methane. The process takes place in a Steam Methane Reformer (SMR), with the endothermic reforming reactions being carried out in catalyst-filled tubes placed in a gas-fired furnace. The SMR is an energy-intensive process unit, and maximizing energy efficiency is of primary interest. However, the high-temperature conditions and large physical scale of the process (hundreds of tubes and burners) pose several operational challenges related to distributed sensing, actuation, and feedback control. Various efforts have been reported on optimization of furnace operation using rigorous computational fluid dynamics (CFD)-based models but, being computationally intensive, these models are unsuitable for real-time optimization. In this paper, we present an integrated framework that relies on the use of advanced temperature sensors, soft sensors, and reduced-order and rigorous SMR CFD models for distribute...