Showing papers in "Computers & Chemical Engineering in 1996"

TL;DR: In this paper, a nonlinear principal component analysis (NLPCA) method which integrates the principal curve algorithm and neural networks is presented. But when applied to data sets the algorithm does not yield an NLPCA model in the sense of principal loadings.

TL;DR: The MINLP problem for the optimal synthesis of process networks is modeled as a discrete optimization problem involving logic disjunctions with nonlinear equations and pure logic relations, and it is shown that it is possible to derive a logic-based method for the latter algorithm.

TL;DR: A novel branch-and-bound algorithm that branches on both discrete and continuous variables is proposed to address the large integrality gap in the formulation of this mixed integer linear programming (MILP) problem.

TL;DR: In this paper, a brief overview of the use of multivariate statistical process control methods for process monitoring and fault diagnosis with applications to a wide range of industrial batch and continuous processes is presented.

TL;DR: This paper identifies a number of key issues regarding the development of general modelling languages for combined lumped and distributed parameter processes, and proposes one such language and shows the capability of the proposed modelling system to deal with a wide variety of complex processes described in terms of IPDAEs.

TL;DR: The purpose of this review is to sketch the directions that research and industrial applications of “intelligent systems” have taken in several areas of process engineering, and identify the emerging trends in each area, as well as the common threads that cut across several domains of inquiry.

TL;DR: How mathematical programming techniques can be applied to the problem of scheduling the crude oil supply to a refinery is indicated, and the advantages of using such approaches are highlighted.

TL;DR: The state of the art and current trends in computer-aided modeling are presented in this contribution which is intended to serve as a survey and a tutorial at the same time.

TL;DR: This work proposes alternative ensembles for the KL decomposition that address some of the shortcomings of the usual procedure, and shows how different ensemble averages give different results for the representation of “intermittent” attractors.

TL;DR: In this article, a unified mathematical formulation of the problem of determining the optimal operating conditions of a mixed production facility, comprising multipurpose plant for both batch and continuous operations, is presented.

TL;DR: An algorithm suitable for the global optimization of nonconvex continuous unconstrained and constrained functions is presented and is shown to be more robust and more efficient in what concerns the overcoming of difficulties associated with local optima, the starting solution vector and the dependency upon the random number sequence.

TL;DR: The aim of this work is to extend the computerized method for process pre-design to encompass safety aspects by integrating the synthesis method into an existing computer aided process design tool.

TL;DR: A sequential set of tests for model-based Real-Time Optimization (RTO) system design is presented, using the framework of the Design Cost Criteria to evaluate design alternatives.

TL;DR: In this paper, an on-line computational technique has been developed and used in the analysis of hydraulic transients caused by leakage, in order to detect and locate pipeline ruptures.

TL;DR: In this paper, a mathematical programming approach is presented that can be used to streamline the operations and suggest design modifications that will improve the efficiency and responsiveness of the supply chain of a fine chemical industry.

TL;DR: It is argued that a number of important research challenges remain to be solved with major themes being fundamental integration of different synthesis methodologies, improved robustness of optimization-based methods for predicting solutions of good quality, and improved capabilities for handling larger problems.

TL;DR: A global optimization algorithm, αBB, for twice-differentiable NLPs, operates within a branch-and-bound framework and requires the construction of a convex lower bounding problem.

TL;DR: In this article, a two-stage approach for retrofit heat exchanger network (HEN) design, consisting of a modification selection stage and an optimisation stage, is described. And the resulting HEN is then optimised during the optimization stage, using nonlinear optimisation techniques, to minimise the cost of additional surface area employed.

TL;DR: In this article, the first and second laws of thermodynamics are used to motivate a theory for nonlinear process control, including positive entropy production, boundedness of entropy in terms of energy, concavity of the entropy density and Helmholtz free energy as a storage function.

TL;DR: The systematic identification of both noncyclic and cyclic species was carried out by constructing the structurally explicit decomposition tree, an assembly of the biconnected components of the graph, from which a graph invariant unique string code was obtained by iteratively encoding and ordering the subtrees of the decomposition trees.

TL;DR: In this paper, the application of Mixed Integer Programming (MIP) techniques for the optimization of site utility systems is addressed, where an industrial example is used to demonstrate MIP techniques for optimization of plant utility systems.

TL;DR: Experiments indicate that the interval Newton/generalized bisection method works quite well on relatively small problems, providing a powerful method for finding all solutions to a problem, at least when reasonable initial bounds are not provided.

TL;DR: In this article, a balanced control structure and controller tuning procedure is proposed to handle large load changes while maintaining good dynamic performance in a reactor/separator process and a systematic tuning procedure was also proposed to find the controller parameters in plantwide control.

TL;DR: In this article, the means-ends paradigm has been modified to include the idea of strategic operations in addition to opportunistic operations, where the input state for strategic operations may not completely instantiated at the time they are applied.

TL;DR: A combined multiperiod/stochastic optimization formulation is proposed along with a decomposition-based algorithmic procedure for its solution and is illustrated with a process synthesis/planning example problem.

TL;DR: Methods, based on optimization, to assess controllability, to select control structures for a given process (the control system synthesis problem) and to develop integrated designs of process and control system for cases where dynamic performance is critical are presented.

TL;DR: In this article, a general methodology for computer aided product design with specified property constraints is presented, which is capable of solving a large range of problems, including the formation of azeotropes and the miscibility of mixtures for the substitution of compounds.

TL;DR: In this paper, a neural net PLS (NNPLS) approach is used to build nonlinear FIR models which may not be suitable for a direct neural network training approach due to a large number of correlated model inputs which cause large prediction error variance.

TL;DR: This work addresses the nonlinear control of a non-isothermal packed-bed reactor, modeled by two quasilinear parabolic partial differential equations (PDEs) with the aim of building a nonlinear finite-dimensional controller that guarantees closed-loop stability and enforces output tracking.

TL;DR: In this article, the authors present a review of existing strategies for implementing model-based integrated applications for the chemical process industry, including scheduling of multiproduct plants, large-scale model predictive control, integration of planning and scheduling across single and multiple plant sites and design of multipurpose batch plants under uncertainty.