Miguel J. Bagajewicz

• PhD-Caltech
• Professor Emeritus at University of Oklahoma

A novel approach (Complete Set Trimming) to address the globally optimal design of multiple‐unit heat exchangers (Shell and Tube, Double Pipe, Plate, etc.) is presented. Three arrangements: Series, Parallel, Series–Parallel, and Parallel–Series, for minimizing area, CAPEX, or total annualized cost are considered. The geometry of all (equal) units i...

In this article, we extend a previously developed globally optimal enumeration methodology for the synthesis of heat exchanger networks (HENs) to include the basic design of heat exchangers (HEXs). The method addresses together all trade‐offs between network structure, energy usage, and the basic design of the HEXs. Without loss of generality, we f...

In this article, we extend a previously developed globally optimal enumeration methodology for the synthesis of Heat Exchanger Networks to the simultaneous synthesis of the network and the basic design of Heat Exchangers. Our procedure guarantees global optimality, unlike previous approaches, such as Pinch Technology, metaheuristics, or mathematica...

In this article, we use Set Trimming to obtain the globally optimal design of distillation column trays, that is, the column diameter and the geometrical design of the trays (weir, downcomer, etc.) that minimize mass or cost. We assume that the operating conditions (vapor and liquid flow rates, compositions, temperatures) are given. The design task...

The process synthesis problem referred to as work and heat exchange networks (WHENs) asks to determine the optimal heat exchanger network intertwined with compressors, expanders, and valves, all integrated into one single network, such that streams with certain initial temperature and pressure attain their temperature and pressure targets at minimu...

In this article, we present a new generalized model for the steady-state simulation of gasketed-plate exchangers handling single-phase fluids with properties varying with temperature. The model is based on differential balance equations that are discretized using a finite-difference scheme. The set of equations of the proposed model can simulate ga...

The design of double pipe heat exchanger hairpin-based structures has been presented in the form of a mixed-integer nonlinear model (MINLM). While some metaheuristics/stochastic methods can provide good answers, the only way to guarantee global solutions of this model is by using mixed-integer nonlinear programming (MINLP). Our novel contribution f...

We extend a formulation of the heat exchanger design optimization with fouling modeling to consider the effect of fouling on hydraulics. A shell‐side fouling model was added so the optimization can consider cases with fouling in the tube and shell sides. The focus is the design of heat exchangers with fouling behavior associated with a threshold mo...

This article presents the optimization of the design of distillation column trays. We develop a mixed-integer nonlinear optimization model, which we solve using mathematical programming. The objective of this formulation is to size all geometric variables of the tray. Two possible alternative objective functions are tested: column cost and column m...

Intensified shell and tube heat exchangers have been proposed for their use in the grassroots and retrofit designs of heat exchanger networks. Among them are those featuring helical baffles, externally and internally finned tubes, twisted-tape inserts, coiled-wire inserts, and twisted-tube exchangers. Some of these devices are suited for the tube s...

Intensified shell and tube heat exchangers have been proposed for their use in the grassroots and retrofit designs of heat exchanger networks. Among them are those featuring helical baffles, externally and internally finned tubes, twisted-tape inserts, coiled-wire inserts, and twisted-tube exchangers. Some of these devices are suited for the tube s...

In this work, the enumeration algorithms presented in Parts I and II for the globally optimal synthesis of minimal and non‐minimal heat exchanger networks are extended to consider non‐isothermal mixing. New mathematical models, including non‐isothermal mixing constraints, are proposed to target the bounds of energy consumption and the binding excha...

This article addresses the globally optimal design of kettle vaporizers. Established procedures are heuristics-based trial and verification as well as optimization-based that do not guarantee global optimality. The proposed optimization formulation aims at minimizing heat transfer area; the optimal set of the design variables are the tube length an...

In a recent study [Parra, A. et al. Ind. Eng. Chem. Res. 2019, 588 3060−3071], the design of reverse osmosis (RO) systems for desalination of water at different concentrations was studied and optimal solutions were obtained. Equipped now with a powerful tool to solve the problem, we explore its use to determine if RO coupled with a pressure-retarded...

In this work, the enumeration algorithms presented in parts I and II for the globally optimal synthesis of heat exchanger networks are extended to consider non-isothermal mixing. The previous models are modified by adding non-isothermal mixing constraints and new models are constructed to target the bounds of the energy consumption and the binding...

The literature about heat exchanger design optimization encompasses a large number of papers, but only a small fraction is dedicated to phase change systems. This article presents for the first time a linear design optimization approach for horizontal shell and tube condensers that guarantees global optimality. Area is minimized using an integer li...

This work presents a new superstructure for refinery hydrogen networks synthesis. The superstructure eliminates the need to have the pressures of compressors as variables, while both dedicated and shared compressors can be included. As a result of considering the pressures as the parameters known a-priori, the constraint of compression power is exp...

This work presents a new superstructure for refinery hydrogen networks synthesis. The superstructure eliminates the need to have the pressures of compressors as variables, while both dedicated and shared compressors can be included. As a result of considering the pressures as the parameters known a-priori, the constraint of compression power is exp...

In this work, the enumeration algorithms presented in Parts I and II for the globally optimal synthesis of minimal and non-minimal heat exchanger networks are extended to consider non-isothermal mixing. New mathematical models, including non-isothermal mixing constraints, are proposed to target the bounds of energy consumption and the binding excha...

Shell and tube exchanger design has been formulated as a Mixed Integer Nonlinear Model (MINLM) where area or total annualized cost is optimized. Mixed Integer Nonlinear Programming (MINLP) as well as stochastic methods, heuristic algorithms or enumeration were proposed to solve the problem. In almost all previous approaches, global optimality was n...

In Part I of this work, the synthesis of minimal heat exchanger networks using the isothermal mixing stage-wise superstructure was presented. In this Part II, an extension of the algorithm presented in Part I is made to consider networks that allow multiple solutions regarding heat allocation, that is, they have energy loops where heat loads can be...

In Part I of this work, the synthesis of minimal heat exchanger networks using the isothermal mixing stage‐wise superstructure was presented. In this Part II, an extension of the algorithm presented in Part I is made to consider networks that allow multiple solutions regarding heat allocation, that is, they have energy loops where heat loads can be...

This article introduces the concept of minimal structure (MSTR) and presents an enumeration algorithm for the synthesis of heat exchanger networks based on MSTR. Minimal Structures refer to a class of heat exchanger networks featuring acyclic heat transfer networks without energy loops. The enumerations used are either exhaustive or smart with a st...

This article introduces the concept of minimal structure (MSTR) and presents an enu-meration algorithm for the synthesis of heat exchanger networks based on MSTR. Minimal Structures refer to a class of heat exchanger networks featuring acyclic heat transfer networks without energy loops. The enumerations used are either exhaustive or smart with a s...

In this article we compare results from different heuristics approaches for the design of VLE separation vessels. In addition, we present an MILP model that embeds the aforementioned heuristics and considers the discrete nature of the geometric variables. We show that different heuristics render different results. In addition, while results from he...

Despite the large advances in computational tools attained by the PSE community, industry for the most part still performs basic design of process equipment using trial-and-verification procedures guided by heuristic rules. In this opinion article, we present a discussion on how to depart from the use of these heuristics-based procedures, most step...

Design optimization of air coolers is often presented limiting fan calculations to the required power, without considerations of fan capabilities or commercial viability. In this article, new design optimization procedures are presented to include the selection of a commercial-type fan and, thus, the air flow rate as a variable. The resulting model...

This paper investigates the design optimization of double pipe heat exchanger using mathematical programming. The heat exchanger area is minimized and the thermo-fluid dynamic conditions are considered for the use of the right transport correlations, together with design specifications, such as, maximum pressure drops and minimum excess area. The m...

This study presents a globally optimal linear procedure for the simultaneous design of cooling water systems. The optimization entails obtaining optimal pipe diameters, pump selection and detailed cooler design. For the latter, the Kern model and the linear formulation proposed by Gonçalves et al. (2017) were used. The proposed linear model is comp...

In this article, we present a rigorous reformulation of the Bell–Delaware model for the design optimization of shell and tube heat exchanger to obtain a linear model. We extend a previously presented methodology1,2 of rigorously reformulate the mixed‐integer nonlinear programing Kern model and we add disjunctions to automatically choose the differe...

In this work, we propose a methodology to solve a nonlinear mathematical model for the optimal design of RO networks, which ameliorates the shortcomings of the computational performance and sometimes convergence failures of commercial software to solve the rigorous MINLP models. Our strategy consists of the use of a genetic algorithm to obtain init...

This article presents a method for the mathematical optimization of the design of heat exchangers including fouling rate modeling for the tube-side. The description of the fouling rate in crude preheat trains of petroleum distillation units is commonly based on threshold models (Ebert-Panchal model and its variants). Our formulation of the design p...

Even though the last decades have seen an explosion of simulation and optimization tools in Process Systems Engineering, this has not had a significant impact in the basic design of equipment such as heat exchangers, condensers, reboilers, distillation columns, absorption, adsorption columns, etc. To this date most mainstream textbooks advocate the...

In a recent article, Gonçalves et al.,11,12 introduced a linear and rigorous methodology for equipment design, in particular shell and tube heat exchanger. Here, we explore its application to air coolers, a problem that we solve globally for the first time. Because the approach is linear, results are globally optimal. The objective function is the...

Typical heat exchanger design procedures are based on the use of fixed values of fouling factors, mostly based on estimates coming from practice. However, fouling depends on thermofluidynamic conditions (e.g. flow velocity) which values are consequence of the selection of design variables (e.g. baffle spacing). Therefore, the inclusion of fouling m...

We extend the formulation of the Stages/Substages model (see Part I) to account heat capacity variable with temperature, whose influence in designs of heat exchanger network design was not studied. Variable heat capacity (Cp) frequently arises when streams of high molecular weight are used, or when temperature ranges are large, like in petroleum fr...

We solve globally an extension of the isothermal mixing stages model (Synheat) proposed by Yee and Grossmann (1990), later extended to non-isothermal mixing by Björk and Weterlund (2002) and solved globally by Faria et al. (2015). This new extension of that model was recently presented in a Conference Proceedings (Jongsuwat et al., 2014). The model...

In a recent article (Gonçalves et al., 2016) [AIChE J. DOI:10.1002/aic.15556], we presented an MILP formulation for the detailed design of shell and tube heat exchangers based on the Kern approach. The formulation relies on the use of standardized values for several mechanical parts, which we express in terms of discrete choices. Because we aim at...

Fouling is a major problem in the operation of heat exchangers, resulting in increased capital, operational and maintenance costs. Shell-and-tube heat exchangers are traditionally designed using fixed values of fouling resistances, ignoring that fouling rates depend on the exchanger geometry, rendering different fouling resistances for the same the...

Typically, stage-gate procedures define the product first and then, in different stages, determine the commercialization and marketing potentials. We present an alternative to stage-gate procedures for product design, based on the optimization of the whole chain of events simultaneously, from defining the product characteristics, to determining the...

In heat exchangers, fouling is the undesired accumulation of deposits over the equipment thermal surface. This phenomenon causes a gradual reduction of the overall heat transfer coefficient. The traditional approach to handle the fouling problem during the design consists in the introduction of fouling factors in the evaluation of the (dirty) overa...

We present the performance of recently developed techniques on domain and image partitioning (part of the global optimizer, RYSIA) to obtain a good lower bound for the gasoline blending problem. We show that without good initial values, this model cannot be solved using local solvers and we show the need for bound contraction.

The design of heat exchangers, especially shell and tube heat exchangers was originally proposed as a trial and error procedure where guesses of the heat transfer coefficient were made and then verified after the design was finished. This traditional approach is highly dependent of the experience of a skilled engineer and it usually results in over...

Gas lift technology is one of the most common methods used for wells with insufficient reservoir pressure. It makes use of gas reinjection to enhance individual well production. When several wells are used to produce a reservoir, a problem arises regarding the selection about how to produce each well so that overall production can be maximized. To...

We present an extension of a previously presented superstructure (Floudas et al., 1986) for heat exchanger network grassroots design. This extension is such that it includes several matches between two streams, activates splitting control and allows for mixing temperature control. We solve this model globally using RYSIA, a recently developed metho...

We describe a statistical model that uses binomial logistic regression for predicting the solubility of heterologous proteins expressed in E. coli. The model is based on a set of proteins reported to have been expressed in E. coli in either soluble or insoluble form. The 22 parameters used in the final model based on proteins' amino acid compositio...

In this article, the water source diagram (WSD) (Gomes et al., 2007) is extended to the design of water networks involving both fixed flowrate and fixed contaminant load, as well as water loss/gain operations. The algorithm targets minimum external water consumption while simultaneously synthesizing the corresponding water system structure. In addi...

We modify our recently introduced bound contraction methodology for global optimization of bilinear MINLP models1 to solve the stage-wise superstructure model for heat exchanger networks.2 Because the problem has nonlinearities that are not bilinear or quadratic instead of converting the problem into a fully quadratic one, which would add much more...

The minimum number of units in a network has been proposed to be obtained using a very simple formula using graph theory (Hohmann, E. C. Ph.D. Thesis, University of Southern California, Los Angeles, CA, 1971.; Linnhoff, B. et al. Comput. Chem. Eng. 1979, 3, 295). This is done, usually, assuming that thermodynamic feasibility holds, especially in Pi...

We review the performance of different technologies published in a recent patent by Ji and Bagajewicz (2007) aimed at increasing distillates yield. We also present different implementation schemes composed of various combinations of the two technologies and compare both distillate yield and energy expenditure to the current conventional distillatio...

In this paper, we show the implementation of the Generalized Likelihood Ratio (GLR) method to detect and also identify the size and location of leaks in pipelines. We introduce the use of accurate hydraulic models for hypothesis testing and the use of economics to determine the thresholds of detection and identification. We compare the leak detecti...

When there was a lack of computing power, several approximate formulas (Weymouth, Panhandle, AGA, etc.) were developed to obtain pressure drop in gas pipelines, which are in many instances still being used. As it is well-known, they can be sometimes grossly inaccurate, necessitating the addition of an arbitrary parameter (“pipe efficiency”) for eac...

A new heat exchanger network model is presented consisting of an extension of the stage-wise superstructure approach that was proposed by Yee et al. (1990). Motivated by systems where splitting of large FCP stream is needed to match with several smaller FCP streams (like crude fractionation units), we add several matches per branch (Figure 1). Give...

This paper presents a comparison of two heat exchanger network retrofit methods as they are applied to crude units: the well-known and widely used Pinch Design Method (PDM) and a recently developed Heat Integration Transportation Model (HIT), a recently developed mathematical programming-based MILP model [Nguyen et al. Ind. Chem. Eng. Res. 2010, 49...

Using process simulation, this paper analyses the effect of operating conditions on desulphurisation selectivity in high-sulphur gas sweetening process. Furthermore, various influences of the operating conditions on energy consumption were compared by means of a sensitivity analysis tool. The conclusions are: a lot of H2S and CO2 require removed si...

Description This one-of-a-kind, comprehensive handbook provides the latest industry and research advances in petroleum refining, natural gas processing, and refinery management. Over 40 scientists, experts and professionals from both academia and industry have contributed to the 33 chapters in this handbook. Unique features include:

Description This one-of-a-kind, comprehensive handbook provides the latest industry and research advances in petroleum refining, natural gas processing, and refinery management. Over 40 scientists, experts and professionals from both academia and industry have contributed to the 33 chapters in this handbook. Unique features include:

The operating condition impact on energy consumption in MDEA desulfurization process for high-sulfur natural gas was analyzed by using process simulation. These operating conditions discussed included feed gas processing capacity, absorber temperature, absorber pressure, number of absorber trays, stripper temperature, the impact degree of which was...

New Approach to Gas Hydraulics Calculations Mesude Ozturk, Lutfiye Hacioglu and *Miguel Bagajewicz School of Chemical Engineering and Material Science, University of Oklahoma 100 East Boyd Street, T-335 – Norman, OK 73019-0628 USA *corresponding author Abstract The methods used by engineers to evaluate gas-hydraulics in pipelines have n...

One of the biggest challenges in solving optimization engineering problems is rooted in the nonlinearities and nonconvexities, which arise from bilinear terms corresponding to component material balances and/or concave functions used to estimate capital cost of equipments. The procedure proposed uses an MILP lower bound constructed using partitioni...

A global optimization strategy based on the partition of the feasible region in boxed subspaces defined by the partition of specific variables into intervals is described. Using a valid lower bound model, we create a master problem that determines several subspaces where the global optimum may exist, disregarding the others. Each subspace is then e...

A rigorous method based on process equations for designing sensor networks for nonlinear systems was recently proposed (Nguyen and Bagajewicz, Design of Nonlinear Sensor Networks for Process Plants. Ind. Eng. Chem. Res. 2008, 47, 5529–5542). The method has been shown to be efficient for middle scale problems. For realistic large scale problems, the...

In this paper, we address the strategic planning of integrated bioethanol–sugar supply chains (SC) under uncertainty in the demand. The design task is formulated as a multi-scenario mixed-integer linear programming (MILP) problem that decides on the capacity expansions of the production and storage facilities of the network over time along with the...

Traditionally, the sensor network design procedure was based on positioning sensors so that certain network monitoring capabilities (e.g., observability, redundancy, and error detectability) of key variables are assured at minimum sensors cost. We present a new approach that is based on maximizing economic value of information minus cost instead of...

One previous paradigm was based on sensor positioning selection to allow key variable observability. Later, the problem was posed as a minimum cost problem subject to sensor network performance (precision and gross error robustness first and accuracy as a replacement later). In a previous paper (Nguyen and Bagajewicz, submitted for publication), we...

This work studies the problem of optimally locating sensors for monitoring chemical processes, formally known as the sensor network design and upgrade problem. This problem is an integer programming problem and has been solved to global optimality only using tree search methods using depth-first strategy. In this article, we exploit certain cost pr...

We propose a new method to obtain the global optimum of MINLP problems containing bilinearities. Our special method that contracts the bounds of one variable at a time allows reducing the gap between a linear lower bound and an upper bound obtained solving the original problem. Unlike some methods based on variable partitioning, our bound contracti...

In this paper, we present results of a recently developed global optimization method(1) as applied to water management problems. Our method deals effectively with MINLP problems with bilinear and univariate concave terms. Bilinear terms show up in these problems as products of flow rates and concentrations in component balances. In turn, concave te...

Planning models for industrial water systems are needed to address future environmental regulations, increasing costs of freshwater, variability on the quality of the available freshwater source, and bottlenecks caused by expansion of the capacity plant, among other reasons. In this paper, we present a method to address an increase in plant capacit...

This article applies a recently proposed procedure for product design (Bagajewicz, 20071. Bagajewicz , M. ( 2007 ). On the role of microeconomics, multi-scale planning and finances in product design , AIChE J. , 53 ( 12 ), 3155 – 3170 . [CrossRef], [Web of Science ®]View all references) to the design of a wine fermentation monitoring device. The pr...

In this article, we apply a recently developed method for product design to the formulation of skin lotions and extend its application to consider price-competitive markets. The method is based on the use of consumer preference functions that are in turn parameters of price-demand relations. These relationships are then embedded in a business model...

In this paper, we address the strategic planning of supply chains for ethanol and sugar production under uncertainty in the market trends. The design task is formulated as a mixed-integer linear programming (MILP) problem that decides on the capacity expansions of production and storage facilities over time along with the associated sales decisions...

This paper builds upon the MILP model developed by Barbaro and Bagajewicz (New Rigorous One-Step MILP Formulation for Heat Exchanger Network Synthesis. Comp. Chem. Eng. 2005, 1945-1976), which allows the rigorous one-step grassroots design of heat exchanger networks. For the retrofit, we consider the cases of addition and relocation of heat exchang...

In this paper we present a new method for linear and nonlinear sensor network design with applications to variable estimation based on the use of accuracy and residual accuracy. Accuracy has been shown recently to be a better substitute for existing data-reconciliation network properties, such as precision, residual precision, gross error detectabi...

One common assumption used in the design of water/wastewater systems for single components is to fix the process outlet concentrations of the pollutant to its maximum allowed value. This converts the problem from one with nonlinear constraints into one with linear constraints. For problems minimizing freshwater consumption in single-contaminant sys...

In this article, we use a genetic algorithm to obtain an economically optimal preventive maintenance frequency for different equipment, the parts inventory policy (number and type of spare parts to keep in stock), and labor allocation in process plants. To assess cost, we improved a previously published Monte Carlo simulation-based maintenance mode...

Several methodologies to design water systems in process plants are based on minimizing freshwater consumption. The objective is the appropriate one when water is scarce and costs are not a big issue. It has also been used as a substitute for cost in the belief that water and final treatment costs overwhelm other fixed capital and operating costs o...

The definition of the water/wastewater allocation problem is discussed as it was originally defined by Takama et al.1 how this concept was modified, and sometimes simplified, through time, as well as additional issues that is believed are still not properly addressed. A few attempts are reviewed where parts are pointed out, and the addition of wate...

In this article we present a new and more accurate model for the prediction of the solubility of proteins overexpressed in the bacterium Escherichia coli. The model uses the statistical technique of logistic regression. To build this model, 32 parameters that could potentially correlate well with solubility were used. In addition, the protein datab...

Performance data obtained from measurements of process variables usually do not obey material and energy conservation laws. This is why a data reconciliation process, that is, the adjustment of measured data to obey the conservation laws and other constraints is necessary in order to characterize the real performance of equipment, processes, or the...

We discuss the definition of the water/wastewater allocation problem as it was originally defined by Takama et al (1980), how this concept was modified and simplified through time, as well as additional issues that are still not properly addressed. We review a few attempts where parts of our view were pointed out and we further investigate the impa...

A branch and bound procedure based on balance equations of the system (so-called equations-based method) was recently used to solve nonlinear sensor network design problem (Nguyen and Bagajewicz, 2008). The method was shown to be efficient for medium size nonlinear problem, but its computational performance for realistic large scale problems was no...