The Experts below are selected from a list of 35238 Experts worldwide ranked by ideXlab platform
Hideyuki Matsumoto - One of the best experts on this subject based on the ideXlab platform.
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Energy-saving performance of reactive distillation process for TAME synthesis through Multiple Steady State conditions
Chemical Engineering and Processing - Process Intensification, 2018Co-Authors: Takehiro Yamaki, Keigo Matsuda, Duangkamol Na-ranong, Hideyuki MatsumotoAbstract:Abstract We have previously reported the existence of Steady-State solutions where reaction conversion is improved within Multiple Steady States, which appear in the reactive distillation column for tert-amyl methyl ether (TAME) synthesis. In the present study, we examined the energy-saving performance of a reactive distillation process that comprises a reactive distillation column and two recovery distillation columns for Multiple Steady State conditions using Steady-State process simulation. Bifurcation analysis revealed that the Multiple Steady State did not exist under a reflux ratio of 1, but existed under reflux ratios of 2, 3, and 4. The reboiler duty required to obtain high-purity TAME increased with increase in reflux ratio. The evaluation of energy consumption revealed that the reboiler duties of the second recovery column at the Steady-State solutions in the Multiple Steady State were lower than that at the Steady-State solution of reflux ratio 1. Due to the high reaction conversion and reduction of the reboiler duty in the second recovery column, the energy inputs per mole of TAME product at Steady-State solutions of the Multiple Steady State with reflux ratios of 2, 3, and 4 reduced by 17, 12, and 6%, respectively, compared to that for reflux ratio 1.
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Intensification of Reactive Distillation for TAME Synthesis Based on the Analysis of Multiple Steady-State Conditions
MDPI AG, 2018Co-Authors: Takehiro Yamaki, Keigo Matsuda, Duangkamol Na-ranong, Hideyuki MatsumotoAbstract:Our previous study reported that operation in Multiple Steady States contributes to an improvement in reaction conversion, making it possible to reduce the energy consumption of the reactive distillation process for tert-amyl methyl ether (TAME) synthesis. This study clarified the factors responsible for an improvement in the reaction conversion for operation in the Multiple Steady States of the reactive distillation column used in TAME synthesis. The column profiles for those conditions, in which Multiple Steady States existed and those in which they did not exist, were compared. The vapor and liquid flow rates with the Multiple Steady States were larger than those when the Multiple Steady States did not exist. The effect of the duty of the intermediate condenser, which was introduced at the top of the reactive section, on the liquid flow rate for a reflux ratio of 1 was examined. The amount of TAME production increased from 55.2 to 72.1 kmol/h when the intermediate condenser was operated at 0 to −5 MW. Furthermore, the effect of the intermediate reboiler duty on the reaction performance was evaluated. The results revealed that the liquid and vapor flow rates influenced the reaction and separation performances, respectively
Martin Feinberg - One of the best experts on this subject based on the ideXlab platform.
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How catalytic mechanisms reveal themselves in Multiple Steady-State data: II. An ethylene hydrogenation example
Journal of Molecular Catalysis A-chemical, 2000Co-Authors: Phillipp Ellison, Martin Feinberg, Ming-huei Yue, Howard SaltsburgAbstract:Many mechanisms have been proposed for ethylene hydrogenation on catalytic surfaces. In a companion article we discussed how isothermal Multiple Steady-State data can be used to discriminate between rival candidate mechanisms. While most catalytic mechanisms have the capacity to support some pair of Steady States, they will not usually have the capacity to support a particular pair of Steady States observed in the laboratory. The companion article described how chemical reaction network theory can be used to determine whether Multiple Steady-State data are consistent with a given mechanism. Multiple Steady-State data had been obtained previously for ethylene hydrogenation over a rhodium catalyst in an isothermal CFSTR. In this article, these data are used to discriminate between a total of 80 single- and Multiple-pathway mechanisms. Given certain assumptions, it will be seen that only nine of the 80 mechanisms are consistent with the data. The purpose of this article is not to favor one mechanism over another, but to demonstrate the type of refined mechanism discrimination that is possible using even fragmentary Multiple Steady-State data.
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How catalytic mechanisms reveal themselves in Multiple Steady-State data: I. Basic principles
Journal of Molecular Catalysis A-chemical, 2000Co-Authors: Phillipp Ellison, Martin FeinbergAbstract:Multiple Steady States are often observed in isothermal continuous flow stirred tank reactors (CFSTRs) involving heterogeneous catalysis. At least, when certain physical conditions prevail, even fragmentary Multiple Steady-State data can be used to help determine the operative catalytic mechanism. This article describes theory that can ascertain both whether a given candidate mechanism has the capacity to support Multiple Steady States and, more importantly, whether the mechanism has the capacity to support a particular pair of Steady States observed experimentally. In this article, hypothetical examples are used to illustrate the scope, purpose and methodology of this theory. The examples also demonstrate the way in which even partial Multiple Steady-State data provide a basis for highly refined discrimination between very similar mechanisms. In a companion article, actual Multiple Steady-State data are used to discriminate between proposed mechanisms for ethylene hydrogenation on rhodium. A public computer program is available that will allow the user to apply the theory described in this article without knowledge of any underlying theory.
Phillipp Ellison - One of the best experts on this subject based on the ideXlab platform.
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How catalytic mechanisms reveal themselves in Multiple Steady-State data: II. An ethylene hydrogenation example
Journal of Molecular Catalysis A-chemical, 2000Co-Authors: Phillipp Ellison, Martin Feinberg, Ming-huei Yue, Howard SaltsburgAbstract:Many mechanisms have been proposed for ethylene hydrogenation on catalytic surfaces. In a companion article we discussed how isothermal Multiple Steady-State data can be used to discriminate between rival candidate mechanisms. While most catalytic mechanisms have the capacity to support some pair of Steady States, they will not usually have the capacity to support a particular pair of Steady States observed in the laboratory. The companion article described how chemical reaction network theory can be used to determine whether Multiple Steady-State data are consistent with a given mechanism. Multiple Steady-State data had been obtained previously for ethylene hydrogenation over a rhodium catalyst in an isothermal CFSTR. In this article, these data are used to discriminate between a total of 80 single- and Multiple-pathway mechanisms. Given certain assumptions, it will be seen that only nine of the 80 mechanisms are consistent with the data. The purpose of this article is not to favor one mechanism over another, but to demonstrate the type of refined mechanism discrimination that is possible using even fragmentary Multiple Steady-State data.
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How catalytic mechanisms reveal themselves in Multiple Steady-State data: I. Basic principles
Journal of Molecular Catalysis A-chemical, 2000Co-Authors: Phillipp Ellison, Martin FeinbergAbstract:Multiple Steady States are often observed in isothermal continuous flow stirred tank reactors (CFSTRs) involving heterogeneous catalysis. At least, when certain physical conditions prevail, even fragmentary Multiple Steady-State data can be used to help determine the operative catalytic mechanism. This article describes theory that can ascertain both whether a given candidate mechanism has the capacity to support Multiple Steady States and, more importantly, whether the mechanism has the capacity to support a particular pair of Steady States observed experimentally. In this article, hypothetical examples are used to illustrate the scope, purpose and methodology of this theory. The examples also demonstrate the way in which even partial Multiple Steady-State data provide a basis for highly refined discrimination between very similar mechanisms. In a companion article, actual Multiple Steady-State data are used to discriminate between proposed mechanisms for ethylene hydrogenation on rhodium. A public computer program is available that will allow the user to apply the theory described in this article without knowledge of any underlying theory.
Takehiro Yamaki - One of the best experts on this subject based on the ideXlab platform.
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Energy-saving performance of reactive distillation process for TAME synthesis through Multiple Steady State conditions
Chemical Engineering and Processing - Process Intensification, 2018Co-Authors: Takehiro Yamaki, Keigo Matsuda, Duangkamol Na-ranong, Hideyuki MatsumotoAbstract:Abstract We have previously reported the existence of Steady-State solutions where reaction conversion is improved within Multiple Steady States, which appear in the reactive distillation column for tert-amyl methyl ether (TAME) synthesis. In the present study, we examined the energy-saving performance of a reactive distillation process that comprises a reactive distillation column and two recovery distillation columns for Multiple Steady State conditions using Steady-State process simulation. Bifurcation analysis revealed that the Multiple Steady State did not exist under a reflux ratio of 1, but existed under reflux ratios of 2, 3, and 4. The reboiler duty required to obtain high-purity TAME increased with increase in reflux ratio. The evaluation of energy consumption revealed that the reboiler duties of the second recovery column at the Steady-State solutions in the Multiple Steady State were lower than that at the Steady-State solution of reflux ratio 1. Due to the high reaction conversion and reduction of the reboiler duty in the second recovery column, the energy inputs per mole of TAME product at Steady-State solutions of the Multiple Steady State with reflux ratios of 2, 3, and 4 reduced by 17, 12, and 6%, respectively, compared to that for reflux ratio 1.
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Intensification of Reactive Distillation for TAME Synthesis Based on the Analysis of Multiple Steady-State Conditions
MDPI AG, 2018Co-Authors: Takehiro Yamaki, Keigo Matsuda, Duangkamol Na-ranong, Hideyuki MatsumotoAbstract:Our previous study reported that operation in Multiple Steady States contributes to an improvement in reaction conversion, making it possible to reduce the energy consumption of the reactive distillation process for tert-amyl methyl ether (TAME) synthesis. This study clarified the factors responsible for an improvement in the reaction conversion for operation in the Multiple Steady States of the reactive distillation column used in TAME synthesis. The column profiles for those conditions, in which Multiple Steady States existed and those in which they did not exist, were compared. The vapor and liquid flow rates with the Multiple Steady States were larger than those when the Multiple Steady States did not exist. The effect of the duty of the intermediate condenser, which was introduced at the top of the reactive section, on the liquid flow rate for a reflux ratio of 1 was examined. The amount of TAME production increased from 55.2 to 72.1 kmol/h when the intermediate condenser was operated at 0 to −5 MW. Furthermore, the effect of the intermediate reboiler duty on the reaction performance was evaluated. The results revealed that the liquid and vapor flow rates influenced the reaction and separation performances, respectively
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Control of Reactive Distillation through the Multiple Steady State Conditions
Chemical engineering transactions, 2012Co-Authors: Takehiro Yamaki, Keigo MatsudaAbstract:In this paper, the controllability of reactive distillation (RD) on the Multiple Steady States (MSS) was analysed. We used the RD column for tert-amyl methyl ether (TAME) synthesis for a case study. The model was prepared five PI controllers which control liquid level, feed flow rate, pressure of column overhead and bottom product composition. Initial conditions of dynamic simulation were chose three cases each of upper, middle and lower branches on the MSS. Product composition was controlled for the ±10 % disturbances of feed flow rate and reflux ratio. However, pressure disturbance was failed to keep the set point. These phenomena are able to explain the bifurcation diagrams.
Wolfgang Marquardt - One of the best experts on this subject based on the ideXlab platform.
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Computing Multiple Steady States in homogeneous azeotropic distillation processes
Computers & Chemical Engineering, 1994Co-Authors: Achim Kienle, Ernst Dieter Gilles, Wolfgang MarquardtAbstract:Abstract Steady State multiplicity in a single section of a distillation column involving ternary, homogeneous azeotropic mixtures is investigated. Multiple eigenvalues of the equilibrium relation are conjectured to be a potential source for Steady State multiplicity. Continuation methods for large sparse systems are applied to determine operating conditions with Multiple Steady State solutions. An interpretation is given in terms of nonlinear wave propagation theory. Similar phenomena are shown to rise in a distillation column.
