For those interested in tackling industrial optimization problems, typical approaches include either purchasing a sophisticated and often specialised solver perhaps with accompanying consulting support, using an internet-based optimization server or using a Matlab toolbox. While there are a number of open source optimization solvers that enable one to solve a wide range of continuous and discrete, linear and nonlinear, medium and large-scale optimization problems, only a few contain useable pre-compiled binaries for Windows. The initiative described in this work, Opti, bridges this gap by providing an intuitive object-based general optimization platform that interfaces with many of those freely available, and those with low or no-cost licence requirements, high-quality optimization codes all accessible within the rapid development environment Matlab. The user needs not compile or build the various tools, but still leverages off the advantages of using high-end desktop hardware (such as 64bit multi-core processors) and remaining in a powerful and familiar development environment.

Opti: Lowering the Barrier Between Open Source Optimizers and the Industrial MATLAB User

http://egon.cheme.cmu.edu/Papers/MitraSunGrossmann_CHP_Energy_revised.pdf

Optimal scheduling of industrial combined heat and power plants under time-sensitive electricity prices

New methods have been developed for the modelling of steam turbines and gas turbines. In particular, the new models give a better description of part-load performance than previously published models. These models have been incorporated, along with those for the other elements of steam systems, into an overall model for utility cogeneration systems. The degrees of freedom of steam systems allow significant opportunity for cost reduction through optimization. This results from the complexity of the interactions within such systems, the continually changing demands on the system and the complexity of cost tariffs for power and fuel. This paper presents improved methods for both the simulation and optimization of utility systems based on the improved models. Using the method presented, significant cost savings can be made by optimizing the system operation at no capital cost. Case studies show a significant potential for cost savings.

Modelling and Optimization of Utility Systems

Global optimization advances in Mixed-Integer Nonlinear Programming, MINLP, and Constrained Derivative-Free Optimization, CDFO

This work presents a review of the main deterministic mixed-integer nonlinear programming (MINLP) solution methods for problems with convex and nonconvex functions. An overview for deriving MINLP formulations through generalized disjunctive programming (GDP), which is an alternative higher-level representation of MINLP problems, is also presented. A review of solution methods for GDP problems is provided. Some relevant applications of MINLP and GDP in process systems engineering are described in this work.

Review of Mixed-Integer Nonlinear and Generalized Disjunctive Programming Methods

This paper presents a mixed-integer nonlinear programming (MINLP) model for performing structural and parameter optimization of utility plants that satisfy given electrical, mechanical and heating demands of industrial processes. In this model, nonlinear equations are extensively used for the cost of equipment and for the plant performance in terms of enthalpies, entropies and efficiencies. The proposed approach allows for the simultaneous optimization of the configuration, and selection of flowrates, enthalpies and steam turbine efficiencies. All major conventional utility plant equipment are included in the superstructure for the MINLP model. The proposed approach is not only useful for synthesis, but also for analysing different design alternatives. The model has been implemented in the computer package STEAM, and several applications are reported to illustrate the program capabilities, including a comparison with a simplified MILP model.

F. Fernandez

Papers

A Rigorous MINLP Model for the Optimal Synthesis and Operation of Utility Plants