Assay Molecular Weight Data

Assay molecular weight curve data may be supplied which correspond to the distillation basis selected in the Stream Assay Definition Window. Molecular weight curve data are always optional. When the molecular weight curve is not supplied, PRO/II generates the curve using the method selected in the Assay Characterization Options Window.

Usage

From the Stream Data Window, select the "Petroleum Assay" option and push the Flowrate and Assay button to display the Petroleum Assay Stream Window. From this window, push the Define/Edit Assay button to display the Stream Assay Definition Window. Finally, push the Molecular Weight button to display this window and supply the molecular weight curve data.

First check the option to supply a molecular weight curve.

Enter the percents distilled and corresponding molecular weight values in the table provided. The percents must be on the basis chosen for the distillation data - either liquid volume or weight percent. At least three molecular weight points must be supplied to define the molecular weight curve. To add or delete rows from the molecular weight table, use the Cut and Insert buttons. See Editing Tabular Data for additional information.

Optionally, the average molecular weight for the stream may be supplied in the data entry field provided. When the average is given, PRO/II normalizes or extrapolates the curve as required to satisfy the average value for the stream. When the average is not provided, PRO/II uses quadratic extrapolation of the molecular weight curve as needed, to determine the stream average value.

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