Hello,
We are currently trying to control our thermal oil sands blend by adding diluent and butane to get a viscosity of 380 cP. The issue we are having is that the blend points are far upstream of the where the viscosity analyzer is. (The analyzer is owned by the shipping company, and they send the signal to our DCS) The dead time appears to be around 75 seconds. The other issue we are having is that the viscosity of the tanks we are shipping from is not 100 percent constant, meaning with the diluent flow control valve in manual, you would expect the viscosity to be fairly stable but it does fluctuate somewhat.
The other issue we seem to be having is that when we increase our oil shipping flow rate, the amount of diluent we need to add changes and does not appear to be linear. (More oil flow means we need more diluent trim, but the ratio is not linear)
I have been trying to build MPC models, but cannot get them to be accurate. Even worse, when I try to verify the models by selecting all of the current data the accuracy goes out the window.
If anyone has any experience with MPC of this particualr or a similar application it would be appreciated!
Jay