Hi,
I am with my final thesis Masters Degree in Chemical Engineering. It consists basically in using a stripping distillation column (a distillation column without condenser) to recover ionic liquids from 3 different streams. The first stream is ionic liquid with aromatic-aliphatic compounds. The stream is at 40 ÂșC (313 K) and 1 atm. The distillation column model is a radfrac without condenser. My professor's assistant gave me a template with all the ionic liquids since they had researched and pusblished several articles about that, they have a database. He told me to specify a Reboiler Duty, fixing a temperature in the last stage with a Design Specification and with a wide range of variation in Reboiler duty. I did so and this is what I am having in control panel:
<< Loading Simulation Engine 13:59:08 Mon Jul 30, 2018>>
->Processing input specifications ...
* WARNING IN PHYSICAL PROPERTY SYSTEM
THE FOLLOWING CONVENTIONAL COMPONENTS WERE NOT IN A DATA BANK.
CHECK DATA BANK NAMES FOR SPELLING.
CID DATA BANK NAME
C105A104 MMIMNTF2
C105A203 MMIMMECOO
C105A70B MMIMMESO4
C106A101 EMIMBF4
C106A104 EMIMNTF2
C106A107 EMIMFEP
C106A203 EMIMMECOO
Flowsheet Analysis :
COMPUTATION ORDER FOR THE FLOWSHEET:
T-100
->Calculations begin ...
Block: T-100 Model: RADFRAC
Convergence iterations:
OL ML IL Err/Tol
1 1 7 1191.5
2 1 5 763.06
*** SEVERE ERROR
FORTRAN DIVIDE BY ZERO ENCOUNTERED.
3 21 27 5318.4
4 1 10 5596.2
5 1 10 4177.4
6 1 10 1710.6
7 1 10 0.98558E+06
8 1 10 1137.5
9 1 10 145.43
10 1 10 66.430
*** SEVERE ERROR
THE FOLLOWING STAGES DRIED UP (VAPOR OR LIQUID FLOW APPROACHES 0):
10
A LIMIT OF 0.10000E-04 * SUM OF FEEDS WAS IMPOSED ON THE FLOW RATES
OR A LIMIT OF 0.10000E-04 WAS IMPOSED ON THE STAGE V/L OR L/V RATIO.
** ERROR
BLOCK T-100 IS NOT IN MASS BALANCE:
MASS INLET FLOW = 0.47548667E+03, MASS OUTLET FLOW = 0.44608284E+03
RELATIVE DIFFERENCE = 0.65915620E-01
->Simulation calculations completed ...
*** Warning(s) were issued during Input Translation ***
*** Check the Run Status Results for more Information ***
*** Summary of Simulation Errors ***
Physical
Property System Simulation
Terminal Errors 0 0 0
Severe Errors 0 0 2
Errors 0 0 1
Warnings 0 0 0
---------------------------------------------------------------------
I have read that this *** SEVERE ERROR THE FOLLOWING STAGES DRIED UP (VAPOR OR LIQUID FLOW APPROACHES 0) happens with Reboiler Duty specification but I don't have any idea how to solve it and why this is happening. If you have a clue, I would appreciate your help.
Thank you in advance.