A Multilevel MINLP Methodology for the Approximate Stochastic Synthesis of Flexible Chemical Processes

摘要

This work presents a methodology for the optimal design and MINLP synthesis of flexible chemical processes with known probability distributions of uncertain parameters.This methodology comprises synthesis at 1) non-flexible nominal level,2) flexible nominal level,and 3) approximate stochastic flexible level.First level is concerned with modeling challenges of large process flow sheets,sensitivity analyses and studies of uncertain parameters.This level usually results in non-flexible design.Second and third levels take into account flexibility requirements by adding critical points into the model.Both flexible levels rely on considerable reduction of discrete points.Lower levels provide good starting structures for higher levels,therefore,the computational effort is reduced and larger problems with many uncertain parameters,e.g.10 to 100,can be solved.The use of this methodology is illustrated by the synthesis of a flexible heat-integrated methanol process flow sheet.