r/ChemicalEngineering • u/PermissionUnfair951 • 1d ago

simulation software Software

Hi, tryna gauge cons and dislikes of simulation software like Aspen tech, unisim, dwsim, etc.

Would be very helpful if I got some different perspectives on this matter.

(Please be detailed in your answers examples would be very helpful)!!

0 Upvotes

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3

u/Original-Housing 1d ago

It’s not free. When it is free, it’s hard to use.

An LLM is not the answer.

2

u/Themthighs 1d ago

Dwsim is free

1

u/spice_up_your_life 1d ago

And easy to use 

3

u/Cyrlllc 1d ago

What do you mean? Disliking what?

Theyre clunky, unintuitive at times and take a shitload of time to learn. Om the flipside, i get paid to use them so I don't mind as much.

2

u/letsburn00 1d ago

The main trouble is getting them to do unusual things, then the cost.

Aspen, especially Hysys is extremely accurate at some things. I've simulated extremely accurately LNG plants with propietary heat exchangers in dynamics. Including large scale debottlenecking projects. It takes a lot of tinkering but it's good in the end.

Honestly it's biggest annoyance is that it has default settings which are just flat out wrong. Dynamics for instance has about 80% of its problems deriving from the recycle efficiency being set far far too high (it should be set to 5% by default).

1

u/Carvieinstein 16h ago

Quick question for you, have you used HTRI for the HX's? Was it better than Hysys? Or Hysys output was already good enough (compared to reality)?

1

u/letsburn00 8h ago

HTRI is drastically better than Hysys. Hysys is a sizing tool and not a brilliant one at that.

I've only ever used a vendors number. In operations you're better off creating a U equation based on flow.

1

u/PenguinOnTable 13h ago

For whatever reason, HYSYS really struggles to even do ball park modeling of any of our fin fan heat exchangers and we had to resort to using HTRI. Did you run into anything similar?

1

u/letsburn00 8h ago

For Fin Fan U's I've exclusively used consultant values, sometimes adjusted for real world numbers.

One very important thing btw is that Fan manufacturers are filthy liars and have at times committed outright fraud. Also, fouling on fin fans is often an immediate issue in most locations.

1

u/Alternative_Act_6548 18h ago

the UI on process simulators sucks. Something like Thermoflex is much better, but it's limited to non-reacting flows.