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William L Luyben - One of the best experts on this subject based on the ideXlab platform.

  • series versus parallel reboilers in Distillation Columns
    Chemical Engineering Research & Design, 2018
    Co-Authors: William L Luyben
    Abstract:

    Abstract Multiple reboilers are used in Distillation Columns for several reasons such as implementing heat integration, intermediate reboilers, auxiliary reboilers and vapor recompression. If there is a single source of hot vapor to be used in multiple heat exchangers, the flowsheet can use either a series or a parallel arrangement, depending on the temperature levels of the heat sinks. The purpose of this paper is to point out that the series arrangement can present difficult control problems because of interaction between the units. In the parallel configuration, the heat transferred to each sink can be easily divorced from the others. In the series configuration, more complex methods must be used such as bypassing and flooding to adjust heat transfer in individual units. The controllability of the parallel configuration is demonstrated for a lower-partitioned divided-wall reactive Distillation column with vapor recompression.

  • control of a train of Distillation Columns for the separation of natural gas liquid
    Industrial & Engineering Chemistry Research, 2013
    Co-Authors: William L Luyben
    Abstract:

    The recovery of valuable heavier hydrocarbons from natural gas is accomplished in a series of five Distillation Columns. The first and second Columns are cryogenic high-pressure Columns in which the methane and ethane are sequentially taken overhead. The third column produces a propane distillate product. The fourth column removes isobutane and normal butane overhead for separation in the fifth column. The bottoms product from the fourth column is a mixture of hydrocarbons that are heavier than the C4 components.This paper studies the dynamic control of this train of Distillation Columns. Effective control structures are developed and tested on all Columns using conventional PI controllers. The product–quality loops in three of the Columns use tray temperature control, but the first and last Columns require composition controllers to effectively handle disturbances in feed composition. The difficult separation in the large, high reflux ratio de-isobutanizer is well-controlled by an unusual control structu...

  • use of two Distillation Columns in systems with maximum temperature limitations
    Industrial & Engineering Chemistry Research, 2013
    Co-Authors: Rebecca H Masel, Dalton W Smith, William L Luyben
    Abstract:

    Maximum temperature limitations are encountered in Distillation Columns in which thermally sensitive materials are being separated. Fixing the temperature and composition of the bottoms product fixes the column base pressure and, hence, the condenser pressure. The distillate composition at this pressure sets the condenser temperature. In many systems, this temperature is lower than that attainable with cooling water, so expensive refrigeration must be used. Instead of using a single column with a refrigerated condenser, it is sometimes more economical to use two Columns. In the first column, pressure is established to permit the use of cooling water (322 K reflux-drum temperature), and a portion of the light component is produced as the distillate stream. The maximum base temperature limitation is achieved by taking a bottoms stream that is a mixture of the light and heavy components. Then this stream is separated in a second column that uses a refrigerated condenser. The rest of the light component is pr...

  • Design and Control Of Dual Condensers in Distillation Columns
    Chemical Engineering and Processing: Process Intensification, 2013
    Co-Authors: William L Luyben
    Abstract:

    Abstract Most Distillation Columns use water-cooled condensers cooling water that is inexpensive. With cooling water supplied at 305 K, a reflux-drum temperature of 322 K is normally used for column design. This temperature and the distillate composition set the require column pressure. This paper demonstrates that the use of refrigeration in a second condenser in series with the primary water-cooled condenser has economical advantages in some separations. The dual-condenser process can be less expensive than the single-condenser process in cases in which a lighter-than-light-key component is present in the feed and in which the separation between the key components is difficult (low relative volatility systems). Using a small refrigerated condenser permits the column to operate at a lower pressure, which reduces reboiler duty enough to compensate for the small amount of refrigeration required. The dynamic control of the dual-condenser process is also studied, and an effective control structure is developed.

  • comparison of two types of two temperature control structures for reactive Distillation Columns
    Industrial & Engineering Chemistry Research, 2005
    Co-Authors: Devrim B Kaymak, William L Luyben
    Abstract:

    The purpose of this paper is to compare the effectiveness of two different types of two-temperature control structures for reactive Distillation Columns. The first was a structure proposed by Roat ...

Kejin Huang - One of the best experts on this subject based on the ideXlab platform.

  • application of vapor recompression to heterogeneous azeotropic dividing wall Distillation Columns
    Industrial & Engineering Chemistry Research, 2015
    Co-Authors: Li Shi, Kejin Huang, San-jang Wang, Haisheng Chen, Yang Yuan, David Shanhill Wong
    Abstract:

    Although heterogeneous azeotropic dividing-wall Distillation Columns (HADWDCs) can achieve considerable reductions in capital investment and operating cost as compared to conventional heterogeneous azeotropic Distillation systems, their steady-state performance is likely to be greatly enhanced by the application of vapor recompression heat pump (VRHP) technology owing to their unique process configuration of one top condenser and two bottom reboilers and favorable steady-state behavior of relatively small top-to-bottom temperature elevations. In the current work, the feasibility and effectiveness of reinforcing the HADWDC with the VRHP (HADWDC-VRHP) are examined. A systematic procedure is developed to effectively determine the optimum combination of the VRHP and the HADWDC in order to minimize the total annual cost. Two example systems for the separation of isopropyl alcohol and water and pyridine and water with cyclohexane and toluene as entrainers, respectively, are studied to evaluate the steady-state ...

  • Dynamics and control of totally refluxed reactive Distillation Columns
    Journal of Process Control, 2012
    Co-Authors: Kejin Huang, Haisheng Chen, Liang Zhang, San-jang Wang
    Abstract:

    Abstract According to the mechanism of the reaction operation involved, reactive Distillation Columns are often designed to work in a totally refluxed operation mode. The totally refluxed operation mode makes the reflux drum interact solely with the reaction operation involved and retards considerably the dynamics of the latter. The resultant great difference in process dynamics between the reaction operation and the separation operation involved leads frequently to under-damped responses with the degree of under-dampness closely dependent on the inventory control of the reflux drum. With the tight inventory control of the reflux drum, the degree of under-dampness can be suppressed and this presents a favorable effect to process dynamics and controllability of the totally refluxed reactive Distillation Columns. Two hypothetical ideal reactive Distillation Columns with and without a side reaction, respectively, and a high-purity ethylene glycol reactive Distillation column are employed to examine the unique dynamics and controllability of the totally refluxed reactive Distillation Columns. The results obtained are in good accordance with the above interpretation. The current work reveals the general behaviors of the totally refluxed reactive Distillation Columns and can be particularly useful in control system synthesis and design.

  • a fundamental principle and systematic procedures for process intensification in reactive Distillation Columns
    Chemical Engineering and Processing, 2010
    Co-Authors: Kejin Huang, Quanquan Lin, Huan Shao, Chao Wang, Shaofeng Wang
    Abstract:

    A fundamental principle is developed for process intensification through internal mass and energy integration in reactive Distillation Columns and three systematic procedures are devised for process synthesis and design. For reactive Distillation Columns involving reactions with highly thermal effect, process intensification can be achieved with an exclusive consideration of internal energy integration between the reaction operation and separation operation involved. However, in the case of a highly endothermic reaction with an extremely low reaction rate and/or small chemical equilibrium constant, internal mass integration has also to be considered between the reactive section and stripping section. For reactive Distillation Columns involving reactions with negligibly or no thermal effect, process intensification can be performed with an exclusive consideration of internal mass integration. For reactive Distillation Columns involving reactions with moderately thermal effect, process intensification must be conducted with a careful trade-off between internal mass and energy integration. Five hypothetical and two real reactive Distillation systems are employed to evaluate the principle and procedures proposed. It is demonstrated that intensifying internal mass and energy integration is really effective for process intensification. Not only can the thermodynamic efficiency be improved substantially, but also the capital investment can be further reduced.

  • Internally Heat-Integrated Distillation Columns: A Review
    Chemical Engineering Research & Design, 2008
    Co-Authors: Masaru Nakaiwa, Kejin Huang, Takao Ohmori, Akira Endo, Takaji Akiya, T. Takamatsu
    Abstract:

    The heat-integrated Distillation column to be addressed in this paper is a special Distillation column that involves internal heat integration between the whole rectifying and the whole stripping sections. An overview of the research on this process is presented in this work. It covers from the thermodynamic development and evaluations to the practical design and operation investigations for the process. Comparative studies against conventional Distillation Columns are introduced and the results obtained show distinctively the substantial advantages in energy efficiency of the process over its conventional counterparts. Some relevant issues of process design and operation are to be stressed and the results of the first of its kind bench-scale plant experimentation are given in great detail. The application of internal heat integration principle to other Distillation-related processes is also discussed in depth. These include heat integration within batch Distillation Columns, pressure-swing Distillation Columns that are used for the separation of pressure-sensitive binary azeotropes, and different Distillation Columns that have no connections at all. The prospects of the HIDiC and our future research work are then highlighted.

  • parameter analysis and optimization of ideal heat integrated Distillation Columns
    Computers & Chemical Engineering, 2001
    Co-Authors: Masaru Nakaiwa, Kejin Huang, Akira Endo, Takaji Akiya, K Naito, Takashi Nakane, T. Takamatsu
    Abstract:

    Abstract Parametric analysis is performed for ideal heat integrated Distillation Columns (HIDiC) and comparative studies are made with conventional Distillation Columns. Implications of process design and operation variables are clarified and heuristics are provided for the effective process design. A generalized process configuration is suggested, which is demonstrated to have both higher energy efficiency and higher flexibilities than its original configuration. Simulation studies are conducted and the obtained results confirm the conclusion.

Ignacio E. Grossmann - One of the best experts on this subject based on the ideXlab platform.

  • Optimal Synthesis of Complex Distillation Columns Using Rigorous Models
    Computers & Chemical Engineering, 2005
    Co-Authors: Ignacio E. Grossmann, Pio A. Aguirre, Mariana Barttfeld
    Abstract:

    The synthesis of complex Distillation Columns has remained a major challenge since the pioneering work by [Sargent, R.W.H., & Gaminibandara, K. (1976). Optimal design of plate Distillation Columns. In L.C.W. Dixon (Ed.), Optimization in action. New York: Academic Press]. In this paper, we first provide a review of recent work for the optimal design of Distillation of individual Columns using tray-by-tray models. We examine the impact of different representations and models, NLP, mixed-integer nonlinear programming (MINLP) and generalized disjunctive programming (GDP), as well as the importance of appropriate initialization schemes. We next provide a review of the synthesis of complex column configurations for zeotropic mixtures and discuss different superstructure representations as well as decomposition schemes for tackling these problems. Finally, we briefly discuss extensions for handling azeotropic mixtures. Numerical examples are presented to demonstrate that effective computational strategies are emerging that are based on disjunctive programming models that are coupled with thermodynamic initialization models and integrated through hierarchical decomposition techniques.

  • Optimal synthesis of complex Distillation Columns using rigorous models
    Computer-aided chemical engineering, 2004
    Co-Authors: Ignacio E. Grossmann, Pio A. Aguirre, Mariana Barttfeld
    Abstract:

    The synthesis of complex Distillation Columns has remained a major challenge since the pioneering work by Sargent and Gaminibanadara that was reported in 1976. In this paper we first provide a review of recent work for the optimal design of Distillation of individual Columns using tray-by-tray models. We examine the impact of different representations and models, NLP, MINLP and GDP, as well as the importance of appropriate initialization schemes. We next provide a review of the synthesis of complex column configurations for zeotropic mixtures and discuss different superstructure representations as well as decomposition schemes for tackling these problems. Finally, we briefly discuss extensions for handling azeotropic mixtures, reactive Distillation Columns and integration in process flowsheets. Numerical examples are presented to demonstrate that effective computational strategies are emerging that are based on disjunctive programming models that are coupled with thermodynamic initialization models and integrated through hierarchical decomposition techniques.

  • a disjunctive programming approach for the optimal design of reactive Distillation Columns
    Computers & Chemical Engineering, 2001
    Co-Authors: Jennifer R Jackson, Ignacio E. Grossmann
    Abstract:

    Abstract A generalized disjunctive programming formulation is presented for the optimal design of reactive Distillation Columns using tray-by-tray, phase equilibrium and kinetic based models. The proposed formulation uses disjunctions for conditional trays to apply the MESH and reaction kinetics equations for only the selected trays in order to reduce the size of the nonlinear programming subproblems. Solution of the model yields the optimal feed tray locations, number of trays, reaction zones, and operating and design parameters. The disjunctive program is solved using a logic-based outer-approximation algorithm where the MILP master problem is based on the big-M formulation of disjunctions, and where a special initialization scheme is used to reduce the number of initial NLP subproblems that need to be solved. Two examples are presented that include reactive Distillation for the metathesis reaction of 2-pentene and for the production of ethylene glycol. The results show that the proposed method can effectively handle these difficult nonlinear optimization problems.

  • optimal design of complex Distillation Columns using rigorous tray by tray disjunctive programming models
    Industrial & Engineering Chemistry Research, 2000
    Co-Authors: Hector Yeomans, Ignacio E. Grossmann
    Abstract:

    This paper presents a modeling procedure for the derivation of generalized disjunctive programming (GDP) models for the optimal design of complex or thermally coupled Distillation Columns. Optimiza...

  • disjunctive programming models for the optimal design of Distillation Columns and separation sequences
    Industrial & Engineering Chemistry Research, 2000
    Co-Authors: Hector Yeomans And, Ignacio E. Grossmann
    Abstract:

    A disjunctive programming model is presented for the design of ideal and nonideal Distillation Columns in which the feed tray location, number of trays, and operating and design parameters are dete...

Achim Kienle - One of the best experts on this subject based on the ideXlab platform.

  • global optimization of Distillation Columns using explicit and implicit surrogate models
    Chemical Engineering Science, 2019
    Co-Authors: Tobias Kesler, Nick Mertens, Christian Kunde, Dennis Michaels, Achim Kienle, Kevin Mcbride, Kai Sundmacher
    Abstract:

    Abstract Surrogate-based optimization of Distillation Columns using an iterative Kriging approach is investigated. To avoid suboptimal local minima the focus lies on deterministic global optimization. The determination of optimal setups and operating conditions for ideal and non-ideal Distillation Columns, leading to mixed-integer nonlinear programming (MINLP) problems, serve as case studies. To cope with output multiplicities of the model an implicit surrogate formulation is proposed.

  • global optimization of Distillation Columns using surrogate models
    SN Applied Sciences, 2019
    Co-Authors: Tobias Kesler, Nick Mertens, Christian Kunde, Dennis Michaels, Achim Kienle
    Abstract:

    Surrogate-based optimization of Distillation Columns using an iterative Kriging approach is investigated. Focus is on deterministic global optimization to avoid suboptimal local minima. The determination of optimal setups and operating conditions for ideal and non-ideal Distillation Columns, leading to mixed-integer nonlinear programming problems, serve as case studies. It is found that the optimization using the adapted Kriging approach yields similar results compared to the direct global optimization of the original problem in the ideal case, while it leads to a huge improvement compared to a multistart local optimization approach in the non-ideal case.

  • Monotonic reformulation and bound tightening for global optimization of ideal multi-component Distillation Columns
    Optimization and Engineering, 2018
    Co-Authors: Nick Mertens, Christian Kunde, Achim Kienle, Dennis Michaels
    Abstract:

    This paper addresses the problem of determining cost-minimal process designs for ideal multi-component Distillation Columns. The special case of binary Distillation was considered in the former work (Ballerstein et al. in Optim Eng 16(2):409–440, 2015 . https://doi.org/10.1007/s11081-014-9267-5 ). Therein, a problem-specific bound-tightening strategy based on monotonic mole fraction profiles of single components was developed to solve the corresponding mixed-integer nonlinear problems globally. In the multi-component setting, the mole fraction profiles of single components may not be monotonic. Therefore the bound-tightening strategy from the binary case cannot be applied directly. In this follow-up paper, a model reformulation for ideal multi-component Distillation Columns is presented. The reformulation is achieved by suitable aggregations of the involved components. Proofs are given showing that mole fraction profiles of aggregated components are monotonic. This property is then used to adapt the bound-tightening strategy from the binary case to the proposed model reformulation. Computational results are provided that indicate the usefulness of both the model reformulation and the adapted bound tightening technique for deterministic global optimization of ideal multi-component Distillation column designs.

  • steady state multiplicities in reactive Distillation Columns for the production of fuel ethers mtbe and tame theoretical analysis and experimental verification
    Chemical Engineering Science, 1999
    Co-Authors: K D Mohl, Achim Kienle, Kai Sundmacher, Ernst Dieter Gilles, P Rapmund, Ulrich Hoffmann
    Abstract:

    In this contribution, the nonlinear dynamic behaviour of reactive Distillation Columns for the production of MTBE and TAME is studied. The focus is on steady-state multiplicity and a rigorous bifurcation analysis of pilot plant reactive Distillation Columns for both processes is presented. The different sources and physical causes for the existence of multiple steady-states in MTBE and TAME synthesis are discussed. Further, a rigorous experimental verification of steady-state multiplicity in a pilot plant reactive Distillation column for the production of TAME is presented. Finally, some remarks on the implications of multiple steady-states on column operation are made.

  • Low-order dynamic models for two coupled Distillation Columns
    1999 European Control Conference (ECC), 1999
    Co-Authors: Achim Kienle, E. Stein, A. Rehm, E. Kloppenburg
    Abstract:

    Nonlinear low-order models are developed for two coupled Distillation Columns separating a ternary mixture of methanol, ethanol and 1-propano!. The approach is based on well-known spatio temporal pattern formation phenomena in Distillation processes also termed as nonlinear wave propagation. In a first step, the energy balance is neglected assuming constant molar flow rates in each column section. Further, constant molar holdups are assumed. In a second step, the wave approach is extended for Columns with variable flow rates and constant volumetric holdups. It is shown that these assumptions are more realistic for the process considered here. In both cases the low-order models are in good agreement with the corresponding reference models with constant and variable flow rates, respectively. Further, the reduction of the system order is considerable in both cases.

San-jang Wang - One of the best experts on this subject based on the ideXlab platform.

  • application of vapor recompression to heterogeneous azeotropic dividing wall Distillation Columns
    Industrial & Engineering Chemistry Research, 2015
    Co-Authors: Li Shi, Kejin Huang, San-jang Wang, Haisheng Chen, Yang Yuan, David Shanhill Wong
    Abstract:

    Although heterogeneous azeotropic dividing-wall Distillation Columns (HADWDCs) can achieve considerable reductions in capital investment and operating cost as compared to conventional heterogeneous azeotropic Distillation systems, their steady-state performance is likely to be greatly enhanced by the application of vapor recompression heat pump (VRHP) technology owing to their unique process configuration of one top condenser and two bottom reboilers and favorable steady-state behavior of relatively small top-to-bottom temperature elevations. In the current work, the feasibility and effectiveness of reinforcing the HADWDC with the VRHP (HADWDC-VRHP) are examined. A systematic procedure is developed to effectively determine the optimum combination of the VRHP and the HADWDC in order to minimize the total annual cost. Two example systems for the separation of isopropyl alcohol and water and pyridine and water with cyclohexane and toluene as entrainers, respectively, are studied to evaluate the steady-state ...

  • Dynamics and control of totally refluxed reactive Distillation Columns
    Journal of Process Control, 2012
    Co-Authors: Kejin Huang, Haisheng Chen, Liang Zhang, San-jang Wang
    Abstract:

    Abstract According to the mechanism of the reaction operation involved, reactive Distillation Columns are often designed to work in a totally refluxed operation mode. The totally refluxed operation mode makes the reflux drum interact solely with the reaction operation involved and retards considerably the dynamics of the latter. The resultant great difference in process dynamics between the reaction operation and the separation operation involved leads frequently to under-damped responses with the degree of under-dampness closely dependent on the inventory control of the reflux drum. With the tight inventory control of the reflux drum, the degree of under-dampness can be suppressed and this presents a favorable effect to process dynamics and controllability of the totally refluxed reactive Distillation Columns. Two hypothetical ideal reactive Distillation Columns with and without a side reaction, respectively, and a high-purity ethylene glycol reactive Distillation column are employed to examine the unique dynamics and controllability of the totally refluxed reactive Distillation Columns. The results obtained are in good accordance with the above interpretation. The current work reveals the general behaviors of the totally refluxed reactive Distillation Columns and can be particularly useful in control system synthesis and design.