Tips & Tricks: Creating User Component Databases

The creation of a user component database is sometimes the most efficient way of getting information inside VMGSim for flowsheeting purposes. To implement such a thing there are 3 steps that must be followed:

Step 1 – An XML type file(s) must be created that holds the user component data.

These components can be as simple or complex as desired and reside within the chemical family of the user’s choice. In order to create an oil assay component slate the below Excel spreadsheet was used to generate the XML type file called "oilExample.asc". The components created consist of 10 oil assay cuts as shown in the below image of chemical family type "OIL".


Note that underscores are NOT allowed in component names.

Once created in the XML based format the "oilExample.asc" file can be viewed to confirm data from the Excel spreadsheet was generated correctly.

Similar rules apply to these generated user components as to hypothetical components within VMGSim (i.e. A minimum of the normal boiling point, or liquid density and molecular weight, is required).


In addition to the oil assay components there are three types of coal feeds for a gasification unit also desired by the user within VMGSim.  These are created as "Gasification components" chemical family type components as shown below, which includes information on the solidification of the coal and overall enthalpy of formation balance.  These extra component properties, which are case sensitive, can be seen listed down the first spreadsheet column.


Step 2 – XML type file(s) created need to be referenced for VMGSim use in vmg.ini.

The XML type file, or files, created can be referenced into VMGSim’s pure component database by editing the "…\VMG\VMGSimPkg\vsimcom\vmg.ini" text file. The key word "UserDB", which is case sensitive, should be used and afterwards any user component database files should be listed wrapped in single quotations. These single quotation wrapped file locations should be wrapped by double quotations overall as shown below.

If you have a single user database, that file name should have only double quotations around it. The single and double quotations are necessary only when adding multiple user databases. If both single and double quotations go around only 1 database file name the line will fail.


Step 3 – Created user component names get added in Yaws.txt.

Any user component names within the XML type database files referenced need to be added to the "…\VMG\VMGSimPkg\Yaws.txt" text file. These names can be proceeded with other specific information about the component.


The user components created can now be found within the pure component list in VMGSim with these 3 steps completed.


Please contact your local VMG office for more information.

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