3 replies to this topic

[skyicetel1]

I'm making amine sweetening process as a homework with pro/ii

but, I couldn't get any information of damping factor

I googled, there was only about speakers

Can I get some information?

[latexman]

I'm not familiar with pro/ii, but I do have experience with a dampening factor in a couple other similators.  In the numerical mathmatics to solve the column's MESH (material balances, equilibrium conditions, summation conditions, and heat balances) equations, there are iterative methods to predict or project the next better guess.  Newton's Method comes to mind.  Sometimes, especially if the projection is aggresive, there could be "overshoot" and instabilities.  The "dampening factor" is a way to reduce the projection and add stability to the iterative solution.  The dampening factor is usually a value between 0 and 1, say 0.5 for half the calculated projection.  It adds more iterations and more time to the problem, but it does add stability, i.e. the simulation is less likely to not converge or "crash".

[Pilesar]

latexman gave correct answer. If your column solves, no damping factor below 1 is needed since the solution with and without damping would be equivalent and just as rigorous. The column solution algorithm uses simplifying assumptions during internal unit iterations which are supposed to move toward the final converged solution. A damping factor below 1 is a way to tell the simulator 'take baby steps toward the solution since there is a lot more non-ideality than usual for this system and the internal simplifying assumptions are causing some problems.' For amines, damping factor of 0.6 or 0.8 may be needed. The 'right' damping factor is the one that allows column convergence so may need some trials. If your column does not converge, the usual culprit is bad column specs. Amine columns are the only ones where I have seen routine use for damping.

[skyicetel1]

I thought that damping factor is something about physical factor of column. thanks