Equilibrium Calculation

The Equilibrium calculation can be a useful tool to assess the fluid behavior at various conditions quickly. As with the child models, the corresponding page for it can be accessed from the left navigation panel, as well as directly from the fluid model overview.

Inputs

When accessing the page, we see that there are three inputs required, a temperature, pressure and a composition.

The composition will have to be copied into the slots for now, but the optionality to select a sample from the associated project is underway. Note that we also have to make sure the component slate is corresponding to the input components here - easily done by copying a composition from the detailed fluid model overview, shown below.

Now you can try filling in conditions until you are in the multi-phase region.

Results

Having run the calculation, five tabs will pop up, with the initial results showing us the flash calculations.

Utilizing a temperature of 200 fahrenheit and a pressure of 2000 psia, we see that we are in the two-phase region for this fluid.

With this, we can get a prediction for our compositional phase behavior, seeing the mole ratio of the phases along with some properties at these phase conditions.

Another useful property yielded by this calculation is the saturation pressure at the conditions given, which can be viewed when switching tabs.

Here, we see that the Psat is at 3370.26 psia, while it is a bubblepoint (indicated by the fact that we have a liquid faction of 1 and a 0 vapor fraction at this Psat).

Next Step

Having successfully ran a equilibrium calculation to a two-phase region, the next step is to generate a Phase Envelope.