Emptying a tank on HYSYS

[Abirus]

Hello, after multiple attempts to empty five tanks in my HYSYS simulation, I could't do it. The tanks are filled with oil to a level of 80%, the valve of filling is fully closed, and the valve of the emtying is fully open. I installed a PID Controller, and i chose as a set point 5% than 50% but the level of the oil in the tanks remains the same?

Is there any idea or action to take in order to empty the tanks? Thank you.

PS: the filling works perfectly, only the emptying that doesn't work.

 

[LittleInch]

Somewhere for the fluid to go?

A drawing or schematic in hysys might explain what is wrong

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Abirus]

Thanks for your remark, I just added a schematic in HYSYS. I hope it is clear now.

 

[MortenA]

In your schmatics whats the driving for - it seems like its only elevation difference?

--- Best regards, Morten Andersen

 

[Abirus]

Yes, the elevation difference is what drives the liquide to come out of the tanks.

 

[MortenA]

So are you sure that you got all the elevations right and didnt set one so high that there is no outflow? I seem to remember that setting the levels for the tank and getting the datum right is a little tricky...

--- Best regards, Morten Andersen

 

[pierreick]

Hi,
You should start with a simple model and check if it works !
my 2 cents
Pierre

 

[Abirus]

MortenA yes I did, I set the inlet at 1m (which is the case in reality) and the outlet at 0.5m.

pierreick good point, I will try it and see.

 

[TiCl4]

Abirus,

Pierreick makes a great point. When building a large and complex model, it is good practice to stop periodically during the model construction and test recently implemented changes to ensure they are working. Though this may involve some extra work to set up and deconstruct the necessary blocks for testing, this helps immensely when troubleshooting and ultimately saves time.