A superstructure representation, generation, and modeling framework for chemical process synthesis

Abstract

We present a framework for the efficient representation, generation, and modeling of superstructures for process synthesis. First, we develop a new representation based on three basic elements: units, ports, and conditioning streams. Second, we present four rules based on "minimal" and "feasible" component sets for the generation of simple superstructures containing all feasible embedded processes.Third, in terms of modeling, we develop a modular approach, and formulate models for each basic element. We also present a canonical form of element models using input/output variables and constrained/free variables. The proposed methods provide a coherent framework for superstructure-based process synthesis, allowing efficient model generation and modification.

Simultaneous chemical process synthesis and heat integration with unclassified hot/cold process streams

“…While the unit operations can be modeled using various methods (Bausa, Von Watzdorf, & Marquardt, 1998;Boukouvala & Ierapetritou, 2013;Gani & Bek-Pedersen, 2000;Kong, Sen, Henao, Dumesic, & Maravelias, 2016), in this work we adopt a "flow based" formulation (Kong et al, 2016;Wu, Henao, & Maravelias, 2016). First, a unit selection binary variable ( ) is introduced for each alternative unit ( ∈ ) so that = 1 if the unit is selected.…”

Pattern recognition in chemical process flowsheets

“…This graph can be used for representing and analyzing a process system. Several other graph representations were developed for solving process synthesis problems . However, instead of defining two different types of nodes like STN and SEN, we introduce nodes in our graph that represent the raw materials, products, and process units in flowsheets.…”

Process synthesis using block superstructure with automated flowsheet generation and optimization

“…Mathematical descriptions of process units that are present in a superstructures are provided through models with varying degrees of detail and complexity. While a general practice is to use simplified models such as sharp/nonsharp separator models, short‐cut equipment design models, stoichiometric reactor models, and so forth, the use of surrogate models for capturing the detailed design characteristics of the process equipment have been also successful …”

“…The directed connections from output nodes to input nodes represent the process streams. Wu et al established the unit‐port‐conditioning‐stream (UPCS) framework for superstructure representation and developed connectivity rules to simplify the fully connected superstructure while maintaining all feasible connections. Lutze et al constructed a comprehensive framework for chemical process synthesis and intensification starting from process phenomena building blocks.…”