Overview

OLI Flowsheet: ESP, like any other good process simulator, has different paths to input your data. This article discusses how to enter your components.

Disclaimer

This article was created using OLI Flowsheet: ESP version 12.0. More recent versions of the OLI Flowsheet: ESP software may have different values, but the concepts remain the same.

Units

For this article, we will use moles as our unit of measure for component flow.

Component input

Standard input - we know all the flows

For this example, we will create an OLI Flowsheet: ESP chemistry model with the following components:

H₂O
CO₂
SO₂
NH₃
NaOH
HCl

Now let's go to the Flowsheet and create a simple process using a mixer with a single inlet stream and a single outlet stream.

Click on the inlet stream (S-1 in this example) to open up the stream property panel.

Now we will dive into the specifications of the stream input property panel.

The Parameters section is where we will start.

The Total Flow field is currently in mol/hr. Notice that the field is green.  This means we will automatically sum up the inflow components as they are entered. Let's try that now. 

As you see, we started by adding 55.5082 moles of H₂O (which is 1 Kg of H₂O). The Total field automatically updated to the sum, but so did the Total Flow field.

Now let's add a few more components.

Once again, the software has automatically summed up the components into the Total and Total Flow fields. The Total Flow field is still green for the automatic updates.

Overwrite the stream amount

If you have taken any of the OLI training, you might have noticed that we did not use the automatic Total Flow field. There are many times when this is desired and a few times when it is required.

Let's assume we know our stream is exactly 200 mol/h. Enter that value into the stream input.

Notice that the Total Flow field is now white with our entered values. Also, note that the Total field remains the sum of the components.  This raises the question: What is the actual molar flow for each element?

The program will internally convert the component flows into mole fractions. These are then multiplied by the user-entered Total Flow to obtain the actual component flows.

Summary

This article explains how to input chemical component data in OLI Flowsheet: ESP (version 12.0), highlighting two key methods: automatic summation and manual override of the total flow.

By default, individual component amounts are entered, and the Total Flow field, displayed in green, automatically updates as components are added. This approach is useful when the precise quantities of each substance are known, allowing the software to calculate the total stream flow dynamically.

Alternatively, users can manually set a specific value for the Total Flow. When this field is edited directly, it turns white, indicating that the total has been overridden. In this case, OLI Flowsheet: ESP recalculates the component quantities proportionally based on their mole fractions to match the user-defined total.

The article emphasizes the adaptability of the input system, allowing users to define stream compositions either through detailed component data or by imposing overall flow constraints, depending on modeling needs.