Enter test run data for the refinery streams

Click the Fit Distillation Unit button to open the Distillation Unit Fitting dialog.

The Distillation Unit Fitting dialog allows you to specify the nature of the separation into products. This can be done in one of two ways:

• By entering cut points and fractionation indices to define the separation efficiency. See Enter distillation unit parameters.

• By entering measured distillation data ("test run data") for each product, and allowing the distillation unit to be configured by fitting to this data (See: "Enter test run data for the refinery streams" above).

  In depth Since fractionation parameters often represent slightly different parameterizations of the Fenske equation approach to binary separation (upon which the flowsheet computations are based), it is generally recommended that you enter test run data directly for your distillation units. This way, the data is fitted using the same methods as will subsequently be employed in distillation calculations.

You can enter the data by hand, paste the data from an external application such as Microsoft Excel, or import the data from a file. See Import and export data.

To get more space in the dialog to work with the entered data, you can hide the graph by clicking the Hide Graph button at the bottom of the dialog box.

You can choose between the Standard and Advanced grid by clicking the View button at the bottom of the dialog box and choosing the relevant option. For the differences between the two grids, see Standard and advanced grid.

In the grid, products are listed in the columns, and yields and distillation measurements in the rows. The first task is to enter the yield on crude. You need to configure:

• The yield measurement details of the products. Since the yields for your test run data are given as weight ratio on crude, you need to make sure that the first cell of the Yield column shows Yield (wgt) rather than Yield (vol). To change this setting, double-click in the Yield cell and select by wgt from the combo box. Yields must be entered as a percentage.

• The yield values of the products. Enter the yields for the products by typing measurement values directly into each relevant cell.

When these data have been entered, the grid appears as follows:

Next, you need to enter the distillation data. Configure the following:

• The method used to obtain the distillation data. You need to select the method used to obtain the distillation data for the distillation products. Distillation data can be entered for any common method such as D86, D1160 and Simdis. During calculation all measurements are converted to TBP to fit the data. See Distillation correlations.

  

• The temperature unit for the measurements. You must select the temperature unit of the distillation measurements by double-clicking the temperature unit row below the measurement method entries.

  

• The distillation properties for the products. You need to enter the percentages at which measurements were made in the first grey column. Type the percentages for each measurement in the rows of the first column, or copy and paste them from an application such as Excel.

  

When complete the Distillation Unit Fitting grid should like the figure below:

• The distillation data for the products. Enter the distillation data for the products by typing measurement values directly into each relevant cell.

  On entering this data, the grid is complete:

  

  Tip Just as for yield data, any errors (such as inadvertently entering non-monotonic data) will be underlined in red, enabling you to find and correct them.

  Enter as much distillation data as possible. Try to ensure that the distillation data covers a wide spread of input measurements (so 10, 30, 50, 70, 90 rather than 75, 80, 85, 90, 95). When no reference yield is selected the bulk yield curve is reconstructed from the entered yield and distillation data - this reconstructed yield curve is then used during fitting to ensure the generated fractionation parameters result in product distillation profiles that match the measurement data.