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[jprocess]

Adding a "user" defined packing material for use in the tray sizing utility:

As long as the you have the required specifications, you can modify the "packinfo.db" file located in the Support directory. For example, if Hysys is installed in "c:\Program Files\Hyprotech\Hysys", the file we are looking for is located in "c:\Program Files\Hyprotech\Hysys\Support". A typical entry in the packinfo.db file looks similar to this:

PackingType BallastRing_Met1&1_2_inch
Desc "Ballast Rings (Metal) 1&1_2_inch"
SLEFactor 30
RobbinsFactor 30
Diameter 0.0381
Pieces 13000
Weight 415
Price -32767
IDNumber 0
SizeID 2
end



With regards to the info presented above, any units associated with the values are in internal units (i.e. SI).

The Packing Factor (SLE or Robbins) used will depend on the pressure drop correlation chosen.
Hysys defaults to the Robbins correlation (L. Robbins, Dow Chemical, 1991). Based on a quick glance over Robbins' paper, his contention is that Eckert correlates the delta P with the flooding parameter, even when the packing is essentially dry (ie. low values of L/G).
The Robbins packing factor is actually the Dry Bed Packing Factor, which is used to calculate the gas and liquid loading factors (the liq. l.f. is dependent on liquid flow rate), which are in turn used to calculate the pressure drop. The Robbins Packing factor is dimensionless.
In Field units, Fpd=2.7e8 * (rho g/.075) * deltaPpb / (G^2) where rho g is gas density (lb/ft3), G is the gas loading (lb/h-ft2) and delta Ppb is specific pressure drop through dry bed, (in. H2O/ft packing).
The other option is the SLE correlation proposed by Sherwood, and modified by Leva, then Eckert. The packing factor (in inverse feet) is empirically determined, and is approximately the ratio: (surface area of packing per unit volume) / (void fraction in packing)^3.
SLE Factor is in inverse feet.
The "Pieces" entry represents the number of pieces of packing/m3.
The "Weight" entry is the density in kg/m3.
Note that a value of -32767 represents an empty value.


If the customer is interested in evaluating various diameters/sizes of the same type of a certain packing, a separate packing definition for each diameter would be required with each entry having the same IDNumber but a different SizeID as well as different packing type name. If you look through the database file this should become a clearer.

Additionally, when a new packing is added, an entry(or entries) must be added at the end of the file to add the packing type(s) to the list of tray packing available. This entry is of the form:

AddPacking BallastRing_Met1_inch



The last thing to ensure is that you do not use Notepad (or Wordpad or Word) as a text editor. Any of these programs will convert your file to a .txt file even if you try to save as .db (if you check the properties of the file you save it will show "packinfo.db.txt" as the file name). Instead, use the Macro Language Editor in HYSYS (access under "Tools" menu) to open and edit your .db file, then when you save it make sure you use the File Save As and choose Save As Type: All Files (*.*). It will remain a .db file. You can then use your edited packinfo.db in HYSYS.

Cheers.
Mojtaba Habibi