Hello,
I use STAN mainly for water/wastewater balances: factory wide, treatment plant, ... .
A common operation is splitting an incoming flow into 2 or more flows: buffer tank, pump stations, recycle flows, ... .
Since there are no physical or chemical operations in the splitter, all outgoing flows must have the same composition.
Currently, STAN does not make any default assumptions on the outgoing flows.
If the composition cannot be determined from the balance, you have to specify it explicitly, either hardcoded or via relations (= influent composition).
I prefer using relations, since these will pick up any changes made in the ingoing flows, but it can become laborious with many flows/parameters.
Suggestion:
Add an option, e.g. "is splitter", to a process to indicate that all outgoing flows have the same composition.
Under the hood, this could generate additional constraints for each layer (except goods) that all outgoing flows have equal composition.
Or, sets the loads for each outgoing flow and layer (except goods) proportional to their flowrate (goods).
Best regards,
Geert
