Forums
Blogs
Articles
File Library
FAQ
Search
FB
1
Hi everyone,
I am using the in-built example of the carbon capture process by using K2CO3 in HYSYS v.14. I was trying to run the model by changing the feed gas composition and properties but after increasing the flow rate of the feed gas step by step, I failed to converge in regenerator. the error message is as follow:
Rating cannot be done because column COL1 with Tower Main Tower is not converged.
Rating cannot be done because column COL1 with Tower Main Tower is not converged.
Rating cannot be done because column COL2 with Tower Main Tower is not converged.
Rating cannot be done because column COL2 with Tower Main Tower is not converged.
Rating cannot be done because column COL1 with Tower Main Tower is not converged.
* WARNING
PH COULD NOT BE CALCULATED (H+/OH- CONC TOO LOW OR MISSING).
* WARNING
PH COULD NOT BE CALCULATED (H+/OH- CONC TOO LOW OR MISSING).
* WARNING
PH COULD NOT BE CALCULATED (H+/OH- CONC TOO LOW OR MISSING).
* WARNING
PH COULD NOT BE CALCULATED (H+/OH- CONC TOO LOW OR MISSING).
Beginning Solution of Column Flowsheet Absorber
***** Generating RateSep Input *****
->Processing input specifications ...
->Executing
Block: ABSORBER
Convergence iterations:
OL ML IL Err/Tol
1 1 3 148.87
2 1 2 52.416
3 1 2 24.974
4 1 1 4.3952
5 1 1 0.19890
RateSep convergence iterations: ABSORBER
Iter Err/Tol
0 14583.
1 2401.5
2 656.85
3 25.297
4 0.36183
5 0.58613E-03
->Generating Results
Block: ABSORBER
Column Flowsheet Absorber Converged
* WARNING WHILE GENERATING REPORT FOR UNIT OPERATIONS BLOCK: "ABSORBER"
(MODEL: "RADFRAC") (PPTRUE.4)
PH COULD NOT BE CALCULATED (H+/OH- CONC TOO LOW OR MISSING).
Beginning Solution of Column Flowsheet Regenerator
***** Generating RateSep Input *****
->Processing input specifications ...
->Executing
Block: REGEN
Convergence iterations:
OL ML IL Err/Tol
1 1 10 6806.5
2 1 4 3296.2
* WARNING
MATERIAL AND ENERGY BALANCES FAILED TO CONVERGE: CHECK COL-SPECS
OR SUPPLY BETTER TEMPERATURE AND COMPOSITION ESTIMATES.
* WARNING
THE FOLLOWING STAGES DRIED UP:
1 3
A LIMIT OF 0.10000E-04 * SUM OF FEEDS WAS IMPOSED ON THE FLOW RATES.
* WARNING IN PHYSICAL PROPERTY SYSTEM
NEGATIVE VALUE OF LIQUID MIXTURE HEAT CAPACITY CALCULATED USING
PROPERTY METHOD ACID-GAS AT T= 225.39, P= 0.17027E+06
AN ABSOLUTE VALUE IS USED.
RateSep convergence iterations: REGEN
Iter Err/Tol
0 79549.
1 0.10341E+07
2 0.89891E+06
3 0.88934E+06
4 0.88685E+06
5 0.88685E+06
** ERROR
VARIABLE RESET ENCOUNTERED IN HOLDUP CORRELATION STICHLMAIR89.
THE PRESSURE DROP CALCULATION FAILED TO CONVERGE. THE CALCULATED
HOLDUP MIGHT BE WRONG. THE COLUMN DIAMETER MIGHT BE TOO SMALL.
** ERROR
RATESEP CALCULATIONS FAILED TO CONVERGE
ITERATIONS DIVERGE
* WARNING
UNUSUAL LIQUID MOLEFRAC PROFILE FOR COMP H2O N2.
PLEASE DOUBLE CHECK THE SOLUTION AND/OR ADJUST FLOW MODEL,
TRANSFER/REACTION CONDITION NUMBERS, PACKING HEIGHT/NSTAGE, ...
* WARNING
UNUSUAL INTERFACE LIQUID MOLEFRAC PROFILE FOR COMP N2 OH-.
PLEASE DOUBLE CHECK THE SOLUTION AND/OR ADJUST FLOW MODEL,
TRANSFER/REACTION CONDITION NUMBERS, PACKING HEIGHT/NSTAGE, ...
* WARNING
UNUSUAL COMPONENT PRODUCTION PROFILE FOR COMP CO2.
PLEASE DOUBLE CHECK THE SOLUTION AND/OR ADJUST FLOW MODEL,
TRANSFER/REACTION CONDITION NUMBERS, PACKING HEIGHT/NSTAGE, ...
* WARNING
UNUSUAL INTERFACE MASS TRANSFER PROFILE FOR COMP N2.
PLEASE DOUBLE CHECK THE SOLUTION AND/OR ADJUST FLOW MODEL,
TRANSFER/REACTION CONDITION NUMBERS, PACKING HEIGHT/NSTAGE, ...
* WARNING
DESIGN SPEC IS NOT SATISFIED BECAUSE ONE OR MORE MANIPULATED
VARIABLE VIOLATED ITS BOUND.
* WARNING
PRESSURE DROP CALCULATION RESULTS MIGHT NOT BE ACCURATE
DUE TO VIOLATION OF CORRELATION LIMITS.
** ERROR
BLOCK H45.REGEN IS NOT IN MASS BALANCE:
MASS INLET FLOW = 0.62167626E+03, MASS OUTLET FLOW = 0.61721693E+03
RELATIVE DIFFERENCE = 0.72249046E-02
Error: Failed to solve the rate-based model!
Column Flowsheet Regenerator Not Converged
I hope someone can help me how to ease this issue?
thanks
