Calculation order management for a sequential-modular process simulator

A Sequential-Modular (SM) process simulator, comprising:

• a computing system including a processor having an associated memory along with a stored simulation algorithm, said algorithm implementing a method of chemical process simulation including calculation order management, said method comprising:
• responsive to receiving a process flowsheet, creating a directed graph (DG) which represents a topology of said process flowsheet that has a plurality of components that are interconnected which each perform chemical process unit operations as nodes and process streams including recycle streams represented as cycles, with dependencies between said process streams adding additional said cycles to said DG;
• partitioning said plurality of components in said DG into a first portion comprising strongly-connected component groups (SCCGs) that along with a remaining second portion comprises individual ones of said components;
• providing an initial location for each of said cycles for said SCCGs to generate a directed acyclic graph (DAG);
• determining an initial calculation order for said process flowsheet from said DAG, including an order for calculation within said SCCGs themselves, and
• graphically displaying said SCCGs and said components as nodes and said process streams as edges with a graphical indication representing each said cycle for said SCCGs, along with said initial calculation order, wherein said initial calculation order is user modifiable.