Modeling experience

[u/Stressedasf6161]

As a process engineer at a polypropylene plant supporting operations, I have noticed that we seldom use simulation software like Aspen or HYSYS. When we do, it is mostly basic fluid properties, hydraulic calculations, or heat loss estimates—never a full H&MB. Who typically handles this level of modeling? Does this match your experience? Is it mostly specialized firms that perform this work? Am I missing something?

[u/Zmyslinski]

It's not uncommon for limited modeling of process units. It likely is an artifact of legacy company ownership and capability. At my current company, we had a very strong modeling presence through the mid 90s. The business unit was divested in the early 2000s. We retained some of the capability and older models through ownership transitions, although level of support was significantly less than historic. Still we repurposed and built upon models for process optimization, new product development ,and troubleshooting. But over the last three years they cut the process development group and global modeling support across the board. Sadly I fear any remnants of the knowledge will end with me. While I never developed models from scratch myself, I was responsibleblrading projects and working with the other engineers building and maintaining the models.

If your company doesn't have any models, it would be an uphill battle to ever generate them. Only chance generally would be in support of an optimization or safety related item. But even still, models are only as good as the underlying assumptions and maintaining them is no small task beyond the initial effort.

[u/APC_ChemE]

I've seen design companies or EPC firms perform this level of modeling as well as companies that have rigourous models for real time optimizers (RTOs).

[u/humhum124]

Technogy licensors

[u/ConfidentMall326]

Your not missing anything and what you are noticing is quite common.

I do heat and material balances like this frequently at my job. I work at a small firm specializing in process engineering. Typically a full H&MB is performed when a client wants to build a new unit, wants to repurpose existing equipment, or wants to expand an existing unit. Since these events do not occur that often in a single plant, a plant process engineer is unlikely to build one of these models. Back in my plant process engineering days I did attempt to build and tune a model to my process unit to look at a potential expansion, but it was difficult because I did not have the modeling know how and experience and neither did the process engineering group at the plant. This is why this type of work ends up getting contracted out to firms who do the work often.

The caveat to this is some larger companies will have dedicated modeling groups to maintain process models, but this certainly is not common to smaller companies.

[u/Flat-Atmosphere-8825]

You’re not necessarily missing anything. Full flowsheet models are often built during design, optimization, or major modifications, while operating plants use simpler calculations because the model needs reliable data and maintenance. Learning simulation is still worthwhile—it helps you understand assumptions and communicate with design or consulting teams.

[u/Prior-Scallion4898]

Yes this sounds pretty typical for a lot of industries. Often an advanced process model can be considered too complex to be worth having, especially for running a plant. Design is another matter, I would expect licensors of process technology to have these models but these will be for their internal use only and won't be sold with the plant.

[u/ChemE586]

Work on the EPC side. Modeling is used extensively during design (steady-state mostly with some dynamic) by EPC and vendor engineers. End customers use the flowsheets as reference but mostly rely on PI data, etc. due to the cost and specialized modeling skills. Here is a “freemium” Microsoft Excel DNA-based system for modeling I developed and I am adding industry unit ops weekly:
https://iengineer.systems/ibalance/ibalance-product.html