PASI 2008
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  PASI 2008
August 12-21, 2008, Mar del Plata, Argentina

Abstracts of Lectures and Seminars

Advanced Modeling Tools

Tuesday, August 12

Lecture: Hybrid Systems: Paul Barton
 Hybrid systems exhibit both discrete state and continuous state dynamics that interact to such a significant extent they cannot be decoupled and must be analyzed simultaneously. This module discusses modeling, simulation, sensitivity analysis and optimization of hybrid systems. The discussion will focus on the continuous time hybrid automaton model for hybrid systems. Local and global optimization problems with both fixed and varying mode sequences will be considered, the latter discussion focusing on nonsmooth and mixed-integer dynamic optimization techniques.

Seminar 1: Tutorial on Equation-Oriented Dynamic Simulation using EMSO: Argimiro Secchi
In this seminar, a tutorial for using an advanced equation-oriented CAPE tool for modeling, simulation and optimization of general dynamic systems, named EMSO (Environment for Modeling, Simulation and Optimization) will be given. The students will learn how to build dynamic models in this environment, carry out some dynamic simulations, and better understand the concepts of dynamic degree of freedom and debugging techniques for detecting inconsistencies of both static and dynamic models.

Seminar 2:  Disjunctive Optimization Tools: Aldo Vecchietti
This seminar present an overview on recent disjunctive optimization modeling, algorithms and techniques. Emphasis will be placed on modeling and solution techniques by proposing several representative examples of discrete continuous linear and non-linear problems and solve them in detail. Examples will correspond to generalized disjunctive models of Process System Engineering and related areas. Recent release of the system LogMIP will be used to perform this task. 

Biosystems Engineering I

Wednesday, August13

Lecture: Protein Folding, De Novo Protein Design, and Signal Transduction Networks: Chris Floudas
The lecture will focus on (a) first principles based approaches for structure prediction in protein folding, (b) in silico sequence selection methods for de novo protein design and validation of the sequence predictions via folding calculations and experiments, and (c) the elucidation of the topology of metabolic and signal transduction networks via gene clustering analysis, prediction of the transcription factors network, and prediction of the upstream network of metabolites.  The lecture will introduce the audience to the problem definitions, the advances made through a multitude of techniques, and present fundamental mathematical modeling and optimization-based approaches.

Seminar 1:  Biotechnology research for biomass-based products other than bioethanol: Telma Teixeira Franco
In the year 2005, thirty and three percent of the GNP of Brazil resulted from agribusiness due to its abundant and diverse agricultural and forest resources. Brazil together with the US is a major producer of bioethanol. Research on the fermentation of sugar cane processes and advanced technologies have extensively been developed towards the bioethanol and yeast production. However, there has been much less research towards the production of other building blocks for industrial application. In this lecture we provide an overview of new developments in biotechnology that are under way towards this objective. These include development of enzyme technology for biomass modification (synthesis and hydrolysis), study of oligosaccharides, structure-functionality, photo bioreactors & fermentation processes for non-bioethanol compounds, active and intelligent packing from natural materials and production of second generation building blocks.

Seminar 2: Is there a Rational Method to Purify Proteins? from Expert Systems to Proteomics: Maria Elena Lienqueo
The purification of recombinant proteins requires several chromatographic steps to achieve a high level of purity. Techniques available include anion and cation exchange, which can be carried out at different pHs, hydrophobic interaction chromatography, gel filtration and affinity chromatography. There are many routes for choosing the efficient number of purification steps to achieve a desired level of purity (e.g. 98% 99,5% or 99,9%). We show how an initial "proteomic" characterization of the complex mixture of target protein and protein contaminants can be used to select the most efficient chromatographic separation steps to achieve a maximum level of purity with a minimum number of steps.

Biosystems Engineering II

Thursday, August14

Lecture: Regulatory networks and biomedical control: Frank Doyle
 We provide an introduction to the modeling and analysis of cellular regulatory networks. Necessary biological background will be provided by reviewing basic concepts of genetic regulation as well as cellular signaling. Examples ranging from the generation of circadian rhythms to the signaling in apoptosis will be used to illustrate modeling and analysis methods. In the second part of the lecture, the synthesis problems in biomedicine will be addressed, with an emphasis on controlled drug delivery. The problem of glucose control for diabetes will be used to motivate the application of key PSE tools for the medical problem.

Seminar 1: Bioengineering challenges of solid-state cultivation: David Mitchell
Solid-state cultivation, which involves the growth of microorganisms on particles of moist solid organic materials, has the potential to produce some microbial products better than submerged liquid cultivation. However, although it is successfully used at industrial scale in the manufacture of soy sauce, it presents many bioengineering challenges that have limited its more widespread use. For example, we do not yet fully understand how growth is controlled by the processes of diffusion and reaction that occur within the particles of solid substrate and within the microbial biomass itself. Further, there is an urgent need to adapt control theory to the operation of solid-state cultivation bioreactors. These and other bioengineering challenges will be discussed.

Seminar 2: Bioprocess Control: from sensor selection to optimized control action: Jorge O. Trierweiler
This seminar  is divided into three parts. First, an overview is given of the current technology applied to measure bioprocess variables (including biosensors). Secondly, it is shown how to combine the available measurements to estimate unmeasured variables using observer techniques (e.g., EKF, CEKF, MHE, etc). The lecture finalizes showing how the control action (e.g., fed batch profile) can be calculated aiming at an optimal and profitable operation. The paper ideas are illustrated by several experimental results and simulated case studies. 

Multiscale Design of New Materials

Friday, August15

Lecture 1 : Cyberinfrastructure enabled Molecular Products Design and Engineering, Venkat Venkatsubramanian
Designing new materials and formulations with desired properties is an important and difficult problem. Cyberinfrastructure plays a crucial role in product design, process development and commercial scale manufacturing by streamlining information gathering, data integration, model development, and managing all these for easy and timely access and reuse. We discuss a cyberinfrastructure framework called Ontological Discovery Informatics to enable the management of complexity, accumulation of knowledge, systematic hypotheses testing by interaction with experiments, and efficient search for new materials with desired characteristics. The application of this paradigm is presented for product design problems in the specialty chemical and pharmaceutical industries.

Lecture 2: Molecular and Multiscale Modeling in Materials Design : Martha Grover Gallivan
Formal methods for process design and process control are routinely applied to macroscopic properties such as temperature and composition, but molecular models are rarely included in the formal design process. Two design and control problems in materials processing will be described that use atomic and molecular interaction models to design materials and the processes to make them.. The first example is in chemical vapor deposition of polycrystalline metal oxide thin films. A key challenge is to select the simplest possible process model to interpret the measurements.  The second example is the design of feed profiles for highly branched polymers. The development of a model relating process conditions and molecular architecture makes possible the design of a process to achieve desired material properties.

Lecture 3: Analysis of complex reaction networks using mathematical programming approaches: Marianthi Ierapetritou
Reactor models based on first principles have been proved to provide accurate results over a wide range of operating conditions, reactor types, charges and transport dynamics. However, a complex kinetic network is most commonly needed that results in excessive computational expense. In this lecture, a number of ideas and approaches will be discussed towards addressing the issue of complexity associated with network representation of reaction systems identifying the most important pathways. Graph similarity and clustering will be discussed using graph-distance metric taking into account the general structure of the graph. Given the distance metric the multiple trajectories corresponding to alternative reaction flux graphs are subsequently clustered to identify similarities among them. Several clustering algorithms can be adopted for this task, including hierarchical clustering; multidimensional scaling et al. The effects of uncertainty in problem data will be also discussed. Ways to account for uncertainty and identify potential alternative solutions with different properties will be presented. Examples varying from metabolic pathway analysis to combustion kinetic models will be used to illustrate the presented ideas. 

Design and Analysis of Complex Engineering Systems

Saturday, August16

Lecture 1:  Complex distillation systems: Pio Aguirre
 This module will present fundamentals and tools of Complex Distillation and Reactive Distillation Systems. Concepts such as Pinch and Residue Curves, Transformed Compositions and Product Composition Regions will be introduced. Applications on different separation processes will be developed.  Thermodynamic aspects for the process synthesis of energetically efficient designs and The Reversible Distillation Sequence Model (RDSM)  will be discussed. Applications of these concepts  in the optimal synthesis of complex distillation systems will be presented.

Lecture 2: Crystal Engineering for Product and Process Design: Mike Doherty
Crystalline organic solids are ubiquitous.  Most small molecular weight drugs are isolated as crystalline materials, and over 90% of all pharmaceutical products are formulated in particulate, crystalline form.  Crystalline intermediates are produced in large amounts to make polymers and specialty products. In most cases the properties of the crystalline solid have a major impact on the functionality of the product and on the design and operation of the manufacturing process.   We will focus on the state-of-the-art, and future directions for the following topics: nucleation, crystal growth, dissolution, crystal shape evolution, polymorph selection and transformation, and the interaction between product and process design.

Seminar 1: Process Design for Mineral Operations: Luis Cisternas
This seminar will present a review of methods for process synthesis with applications in mining operations. The characteristics and special challenges of processes associated to mining will be indicated. Procedures based on superstructures and mathematical programming will be emphasized, although other procedures based in heuristic or hybrid will also be introduced. The applications include, among other, fractional crystallization, mineral flotation, and solvent extraction.

Seminar 2: Eutrophication control in lakes and reservoirs using simultaneous dynamic optimization approaches: Soledad Diaz
The increasing download of nutrients into water bodies throughout the world due to agricultural and industrial activities has intensified eutrophication. Ecological water quality models provide a representation of physical, chemical and biological processes that affect the biomass of phytoplankton, zooplankton and nutrients, through a system of nonlinear partial differential algebraic equations resulting from mass balances for components. We discuss ecological water quality models within a simultaneous dynamic optimization framework. Main focus is global sensitivity analysis, and dynamic parameter estimation and formulation of an optimal control problem to determine restoration policies. Solutions provide optimal profiles for inflows derived to nearby artificial wetlands for remediation, as well as optimal concentrations of zooplankton associated to fish removal, to enhance top-down control of phytoplankton, as main in-lake restoration strategy.

Design of Chemical Processes for Sustainability

Monday, August18

Lecture: Sustainability in the Chemical and Energy Industries : Jeff Siirola
Sustainability will be examined in the context of long term raw material and energy availability, energy intensity, global warming threats, and desire for strong economic growth.   Population and economic trends, material and energy resource and availability data, and elementary systems engineering principles are applied to help elucidate sustainability issues related to global economic growth, raw material choices for the chemical and energy industries, the satisfaction of expected energy needs, and greenhouse gas impacts.  Concepts from chemical structure and carbon oxidation state, stoichiometry, and thermodynamics are useful for understanding and screening among raw material and energy alternatives.  Such analyses can provide guidance for evolving and optimizing overall global chemical and energy industries and suggest that a sustainable future path may be feasible.

Seminar 1: Green Chemistry in Process Engineering : Ofelia de Queiroz F. Araújo
Needs for high efficiency and low environmental risk require a fundamental reevaluation of traditional raw materials, reaction pathways and solvents. While abatement measures mitigate the adverse environmental impacts of production, cleaner production technologies are more advantageous than end-of-pipe technologies. Green Chemistry is a concept driven by efficiency coupled to environmental responsibility. This module will present Green Chemistry principles, sustainability indicators, renewable raw materials, and methodologies to eliminate process wastes and maximize yields. Case Studies related to Carbon Sequestration and Oil Chemistry will illustrate the approach".

Seminar 2: Life Cycle Impact Assessment: a tool in process system engineering : Maite Eliceche
The boundary of process plants in  Life Cycle Impact Assessment are extended to evaluate the major environmental impacts of raw material extraction, intermediate processing, transportation, production and final disposal from cradle to grave. The environmental impacts are quantified using the Heijungs factors that include, Global Warming, Acidification, Eutrophication, Photochemical Oxidation, Ozone Depletion, Human Toxicity, Ecotoxicity, radiations, consumption of nonrenewable and scarce resources, which are weighted for the global potential environmental impact.  Environmental Life Cycle Impact can be used as an objective function in the synthesis, as will be illustrated in the optimal design of a steam and power sector of an ethylene plant.

New Energy Systems

Tuesday, August19

Lecture: Energy Systems Analysis : Rakesh Agrawal
Energy consumption is predicted to increase from the current level of about 14TW to about 28TW by 2050. Alternate energy sources need to be identified and developed to permit the continued functioning of the world economy. This part of the course will present a systematic systems analysis of energy: (i) development and evolution of alternate primary energy sources; (ii) conversion of primary energy to a usable secondary form such as electricity, hydrogen, liquid-fuel etc.; (iii) transportation and delivery of a secondary form of energy; (iv) loss of energy at each of these steps and during use. The presentation will survey some alternative sustainable primary energy sources: solar, wind, nuclear, and bio-based sources. The presentation will also discuss H2 as an energy carrier and conversion of  biomass to liquid fuels. 

Seminar 1: Modeling and Optimization of Biorefineries: Mario Eden
Biomass is considered the renewable energy source with the highest potential to contribute to the energy needs of modern society for both the developed and developing economies world-wide. With a wide range of processing steps and possible products, it is obvious that identification of the optimum process structure can not be done based on heuristics or rules of thumb. Thus there is a need for systematic, reliable methods capable of incorporating different levels of process detail in the decision making framework. This contribution will introduce a systematic framework for modeling and optimization of integrated biorefineries that allows for incorporation of a wide range of models with varying model detail. The challenges in establishing synergistic collaborations in this emerging field will be discussed.

Seminar 2: Product and Process System Design Methodologies for Engineering the Forest Biorefinery: Paul Stuart
The forest biorefinery pathway possibilities are large in number, and will depend on many factors such as wood species, production levels, technology in place, and where the mill is located.  Forest feedstocks such as woodwaste can be gasified into synthesis gas and transformed into chemicals.  Hemicellulose can be extracted from wood chips and converted through enzymatic and chemical transformations. There are numerous complex issues that must be addressed at the process design stage, including energy management, plant-wide analysis techniques, critical technology uncertainties. Interesting biorefinery implementations and pathways will be reviewed and characterized using a systems analysis context.

Enterprise-wide Optimization

Wednesday, August 20

Lecture 1: Enterprise-wide Optimization: Strategies for Integration and Uncertainty: Ignacio Grossmann
EWO involves optimizing the operations of R&D, material supply, manufacturing, distribution and financial activities of a company. Key challenges involve integration of strategic, tactical and operational decision-making, as well as integration of the information, modeling and solution methods. We present three major applications that illustrate handling integration issues, as well as handling of nonlinear and uncertain models.  The first involves integration of planning and scheduling in multiproduct batch and continuous plants highlighting rigorous decomposition schemes. The second involves the global optimization of the scheduling and inventory management of crude oil deliveries in refineries. The third involves the handling of uncertainties in the design and planning of oil and gas fields through a stochastic programming framework.

Lecture 2:  Short-term scheduling: Carlos Mendez
The inherent challenge of scheduling problems has captured the attention of the research community. This module will be focused on the most recent optimization-based techniques for short-term scheduling of batch processes.  Topics will include a comprehensive classification of general characteristics of batch scheduling problems and a detailed study of representative optimization approaches for different problem types. Critical problem features as well as major strengths and limitations of current developments will be discussed. In addition, the application of existing optimization models to the solution of large batch scheduling problems arising in real-world industrial environments will be presented.

Seminar 1: Oil Pipeline Logistics: Jaime Cerdá
Two-thirds of all petroleum products in the US are carried by pipelines. The aim of pipeline logistics is to ensure that the right product is available to meet user needs at the right time, at the right depot and at the lowest cost, and minimum environmental impact. Planning the injection of new product batches in pipelines and the simultaneous product deliveries to depots is a complex task with many constraints. In a dynamic environment, the rerouting of shipments and time-varying product requirements at depots force the scheduler to continuously update pipeline operations. In addition to minimizing operating costs, other pipeline logistics targets aim at running the pipeline close to maximum capacity and permanently tracking batch movements. This work presents an efficient MILP continuous-time framework for the operational management of pipeline networks over a multiperiod moving horizon.

Seminar 2: Simultaneous Scheduling and Control of Multi-Grade Polymerization Reactors: Antonio Flores-Tlacuahuac
Scheduling problems commonly assume constant transition times and neglect process dynamics. Process control problems normally assume fixed production sequences. An important area of application for a simultaneous scheduling and control approach is the polymer industry where transitions times in grade polymerization systems can be long, resulting in considerable amount of off-spec product. The rigorous inclusion of process dynamics for optimal grade transitions in a scheduling formulation is proposed, which leads to a Mixed Integer Dynamic Optimization (MIDO) formulation. The solution presented consists in transforming the MIDO problem into a MINLP, which involves the transformation of the ordinary differential equations that describe the dynamic model into a set of algebraic equations through the use of orthogonal collocation equations.  The seminar emphasizes the analysis of the optimal solutions that are obtained.




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