Custom Unit Stream Normalization Error

[nrgeng]

Two sub-flow sheets are connected in series.The Cases are both solved because the error is from the Custom Unit, the second sub-flow sheet (not shown), that receives the output Stream either Condition 1 or Condition 2.

I have made no changes to any of the preferences. The "Mass balance relative tolerance" is set to 0.001 in the Configuration Menu.

I have emailed two images for your review. Do you agree that everything is the same in the two simulations (images) except the change in PDP from 61 (Image 1, solves) to 62 (Image 2, fails)? What can explain this evidence?

[nrgeng]

After running some new simulations, I have found that the Custom Unit is not transferring all of the Stream compositions between the outer input Stream to the Custom Unit and the internal input Stream within the Custom Unit. The non-normalized error message is the result. I am now working on a shareable file showing this problem.

This confirms what I thought was the problem in my Posting 7.

You might use it to verify the stream array element structure taking note that the last two compositions did not transfer correctly giving the "non-normalized" error.

[jasper]

I am afraid I will need a flowsheet that demonstrates this problem to be able to repair it.

[nrgeng]

I have emailed a sharable fsd which exhibits the problem in COFE 2.7.0.22. The compositions change when passed from outer flowsheet to inner flowsheet so a non-normalization error occurs. Sorry, but the result is the same in COFE 2.9.9.9.

[jasper]

Excellent! Found it. It is a component mapping issue; your inner flowsheet contains two extra compounds and the mapping at the feeds was not done properly. Fixed now, both in the release version (CUP) and alpha version. Thank you for sharing.