Engineers are always looking for ways to save time and reduce errors in process simulation. One time-saving strategy is to use templates in CHEMCAD. Templates allow you to save pre-defined input characteristics for streams or UnitOps, making it easy to duplicate these objects in future simulations. This is particularly useful for processes with repetitive functions such as utility streams or modular processes that require quick replication of standard functions.
Let’s look at a gas processing example. In order to meet gas pipeline specifications, we know we will always need to treat the gas to remove unwanted components like water by contacting the wet gas with glycol, e.g., triethylene glycol (TEG). Once the TEG absorbs the water from the gas, it needs to be regenerated through a standard process that boils off the absorbed water and then cools the regenerated TEG so that it can repeat the cycle.
In this case, I know that I will need to re-create this process over and over again when I am designing a gas processing facility. When you set up stream or UnitOp specifications that you know you’ll need to re-create in the future, you can make a template of that stream or UnitOp. You can then duplicate that item within the same simulation—or in any other simulation—with just a few mouse clicks. Let’s create a template of the regenerator from this example process.
Creating a Template in CHEMCAD
To create a template, first add the stream or UnitOp you want to clone and give it all the characteristics you want to include in the template. In this case, I’ve created a general gas dehydration-regeneration process.
The next step is to find the stream or UnitOp on the Explorer pane’s Simulation tab. Here, we are looking for the regenerator, which is UnitOp ID 4. Expand the Flowsheet item, then expand the Streams or UnitOps item, and finally click to expand the applicable ID.
This brings up an item called Save. Click the word Save to display the Enter Template Name dialog box, then type a name for your new template and click OK. The new template name is now listed beneath the Save item.
Applying a Template in CHEMCAD
You can apply a template within the same simulation where it was created, as well as in other simulations. To apply a template, go to the Explorer pane and expand the Flowsheet item to display the streams and UnitOps that have been added to the flowsheet. Find the item that you want to apply the template to—in this example, the regenerator with ID 47—and expand that item in the list. Here, you’ll see the Save item, followed by the names of any templates that you have created for this UnitOp type (SCDS distillation column).
It’s important to note that for UnitOps in the Flowsheet list, only templates for the same type of UnitOp will be shown; for example, heat exchanger templates are only seen under heat exchanger unit operations. In this case, there is one SCDS template available, which we called ‘TEG Regenerator.’ Click the template name, then choose OK to confirm that you want to apply this template.
Managing Templates in CHEMCAD
You can manage templates and their settings using the Templates item on the Explorer pane. Expand the Templates list to view all available templates for UnitOps and streams, with the UnitOps sorted by equipment type.
From the Templates list, click any template to view its stream or UnitOp specifications. You can also right-click any template name to copy, rename, or delete the template.
Remember that like templates themselves, these actions apply to all CHEMCAD simulations, not just the one you’re working in when you make the change.