Optimization strategies for flexible chemical processes

Recent advances in mathematical programming techniques for the optimization of process systems under uncertainty

The need to develop algorithms for the simultaneous solution of process design and control design problems has been identified by many researchers during the past two decades. However, the multifacetted nature of the problem and the computational burden of the resulting mathematical formulations have restricted progress in this field. This paper introduces a new algorithm for the solution of the simultaneous process and control design problem. The basic idea is to analyze a sequence of combined configurations making use of a bounding scheme to successively reduce the size of the search space. The bounding scheme proposed is based on a steady-state relaxation of the combined problem that generates valid lower bounds and a restriction problem that generates valid upper bounds. Application of the proposed algorithm is illustrated with a number of case studies.

An Algorithm for Simultaneous Process Design and Control

Chemical plants have to be designed based on uncertain thermodynamic, kinetic and equipment performance correlations, market forecasts, raw material and product prices. They have to be able to adjust to changes in operating conditions, disturbance levels, product specifications, product distribution and demand, and they should be able to tolerate equipment malfunction without leading to serious safety hazards. The general term "operability" will be used to describe the ability of the plant to perform satisfactorily under conditions different from the nominal design conditions. Current industrial practice accounts for operability at the design stage in an ad hoc fashion through empirical overdesign factors and by introducing large storage and surge tanks for raw materials, products and intermediates. It is shown here that the heuristic approach is not only often costly and ineffective but that it can have an adverse

Operability, Resiliency, and Flexibility: process design objectives for a changing world

Flexibility and resiliency of process systems

A method of determining rational design margin of unit operation in a process is developed by taking account of parameter uncertainties usually involved in actual process system design. Since decision variables which are to be determined in process system design consist of design variables and manipulating variables, design may be estimated rationally by considering admissible ranges of manipulating variables. The method proposed in this paper is applied to design of a simple chemical reaction process with recycle, and the result obtained by this method is compared with that obtained by the method proposed previously by the authors.

https://www.jstage.jst.go.jp/article/jcej1968/6/5/6_5_453/_pdf

Takeighiro Takamatsu

Papers

On design margin for process system with parameter uncertainty