We’re using Process Analysis 360 software to model a fluid process. The software does not appear to support fluid batch processes natively. The reason is because the connecting lines between process equipment have a storage capacity, like a conveyor line would in moving a hard good from one machine to the next. In fluid processing, this isn’t possible – the batch must be transferred from one machine to the next before the first can start again.
Trying to model this behavior by setting Capacity of connection to 1 doesn't model it correctly. It doesn't quite work.
The reason is because the line connector still has a capacity of “1” unit minimum. What happens is that if a downstream piece of equipment is busy, an upstream unit will still transfer in the connector and “wait” in that connector, while the upstream equipment starts another unit. This is not possible in fluid process as the batch unit cannot sit in a pipe line (the connector here would represent a pipe line and not a conveyor as it is intended with hard good manufacturing).
With this problem, the upstream equipment process begins its next batch while the downstream is still busy with the previous batch, and the “orphan” batch just sits on the connector in limbo. What needs to happen instead is that line connector cannot have any holding value – capacity of “0”. Further, the processes connected by the connector need to integrate – the upstream process cannot transfer its unit until the downstream process is ready to receive it. Because of this limitation we have to build out these production models in Excel manually.