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Tips & Tricks: Use the Case Study to Manipulate and Read String Variables

 The case study can handle multiple types of variables including strings. This article describes how easy is to manipulate string variables or parameters such as Pressure Drop Correlations; and how to read string variables such as content from a process calculator cell.

The example used in this article is simple enough that it can be constructed in less than two minutes and at the same time powerful in the sense that the same concept can be applied in complex simulation models. This approach for manipulating string parameters will allow you visualize the global impact that a parameter like a pressure drop correlation can have in your case.

Let’s start with the example.

1) Open the Pipe Segment case (PipeSegment.vmp) from the Manual Examples folder.

2) Add a Process Calculator unit operation and connect cell B2 to the pressure drop of Pipe1. (Remember to use the copy connection/paste connection feature to streamline the connection process). 

 TT_June_2012_1.png

3) In cell C2 add a formula to evaluate the result of B2. In this example use “High” for values greater than 200 and “Low” for values less than 200.  (Formula:  =IF(B2>200.0,"High","Low").

TT_June_2012_2.png

4) Open the Case Study.

5) Add the Pressure Drop Correlation as Independent variable.

TT_June_2012_3.png

TT_June_2012_4.png

6) Add cells B2 and C2 of the process calculator as Dependent Variables

TT_June_2012_5.png

7) At this moment the case study should look like this:

TT_June_2012_6.png

8) Uncheck the box ‘Run All Combinations’ and assign a different pressure drop correlation to each of the points. Skip the correlations OLGAS_2P and OLGAS_3P if you do not have a licence for them.

A drop down with all the correlations available appears when clicking on each of the Case Study Input Data rows.

TT_June_2012_7.png

9) Now the case study is ready to run:

TT_June_2012_8.png

10) Run and go to the Results tab.

TT_June_2012_9.png

Other examples of string variables/parameters in VMGSim’s unit operations include:

  • Heat Loss Calc Type
  • Kinetic Models in Claus Reaction Furnace
  • Reaction Model in Claus Waste Heat Boiler 

 Please contact your local VMG office for more information.

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