Equation Analyzer

Introduction

The equation analyzer is an advanced user tool. It allows the user to view the set of simultaneous equations. Why? Situations where there are too many or too few specifications can be analyzed (though that is rarely needed). If the solution is singular, or if the equation solver fails, then this tool provides information about which equations (and hence unit operations) may be causing the problems.

This is not a tool that you should expect to use much. Petro-SIM strives to make dynamics robust and easy to use, without users having to be concerned about solver failures or such implementation artifacts. If you do get pressure flow convergence failures in Petro-SIM, please send the case in to KBC.

You can access the equation viewer by clicking Simulation, Equation Summary View.

Main View

Full and Partitioned Analysis are two options to analyze equations and find redundant specifications or missing specifications. If one option does not provide something useful, try the other. These two approaches work by analyzing the simultaneous equation matrix and possibly changing (partitioning) equations to facilitate better identification of problem areas.

The dynamics assistant can be used as an alternative to study over or under specified problems. It relies on a general approach rather than analyzing the equations. The PFD also has an option to show which streams have flow and pressure specifications.

The general equations tab contains a list of all the equations that the integrator solves. Double click on an equation to see more details for it.

If applicable, unconverged equations are shown on the Unconverged tab. This allows you to see where in the flowsheet the problem may be. Unconverged equations usually result from unusual situations, such as a spreadsheet possibly specifying a pressure of 1e11 kPa.

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