Aspen Plus blocks RadFrac

The next simulation is for the same column, but using the RadFrac block in Aspen Plus. The feed is the same, the pressure is 138 psia, and the Refinery/Chao-Seader property method is used. This example uses 26 stages, and you run Aspen Plus to see what the split is. (Notice that you cannot easily set the split and find the number of stages or reflux ratio needed to achieve it.) Set the reflux ratio to 3.44 and enter the feed on the thirteenth stage. 

In designing a conventional single column, the RadFrac model in Aspen Plus is used. To use a. MultiFrac model with a Peflyuk configuration, select the appropriate icon and drop it onto the process flow diagram as shown in Figure 12.2. Then feed, distillate, and bottoms material streams are added as shown in Figure 12.3. The model block is labeled DWC. 

Sidestream Column. The RadFrac block in Aspen Plus can be used for the ordinary distillation column with one feed stream and two outlet streams (distillate and bottoms). This block can also be used for multiple feed streams or more than two ordinary outlet streams. For example, the extractive distillation column in Section 3.1 demonstrated that two feed streams can be connected to the RadFrac block. In a similar way, more outlet streams can be drawn out of the RadFrac block as a sidestream column. The sidestream draw-off can be either a liquid stream or a vapor stream. AU these varieties of different columns can easily be configured by adding material streams to the flowsheet with the RadFrac block (see previous Fig. 3.5). 

With the use of the RadFrac unit operation block in Aspen Plus, the heating (reboiler) and the cooling (condenser) equipment of a distillation eolumn are built in with the column... 

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