7 replies to this topic

[sherkhan_95]

Hello everyone....

I have simulated my plant using hysys version 2006.5... we are using MDEA as a solvent... i want to see the effect of amine blends like MDEA+DEA or MDEA+MEA etc...

Now problem is that when is entered in hysys basis environment and adds DEA or MEA and when i enter again in simulation environment stripper becomes unconverge... (even 2nd amine conc is zero in all stream)..

can anyone tell me that what is the problem? ? am i  to use another version or is this some other sort of problem??

 

 

 

Regards 

M Sher Khan

 

[shantanuk100]

Hello Sher Khan,

 

Your question is a bit unclear, so maybe a little more detail might help out.
Could you mention in detail what inputs you have taken, and what outputs you wish to study and the problem you are facing ?

That way It will be easier to help you out.

 

Regards,

Shantanu

Edited by shantanuk100, 23 November 2015 - 05:06 AM.

[sherkhan_95]

Hello Shantanuk

The problem i am facing is that, i have successfully simulate my plant in HYSYS version 2006.5, The solvent we are using is MDEA which i selected in my base case, and studied different parameters, both absorber and stripper are fully converged and all sreams fully solved.... I want to see the effect of amine blend means that I want to see the effect of MDEA+MEA or MDEA+DEA, so when i goes to Hysys basis manager and put additional amine like DEA in component list but after returning to the simulation environment again, the case becomes unconverge..... but when i  removes the additional DEA the simulation case becomes converge ...... Do u got the point? 

[shantanuk100]

Hello Sher Khan,

 

Check out these cases :

 

1. You have converged the column but then entered a new component. So have you checked if the inlet to absorber component mole fractions have gotten reset upon adding a new component by any chance, and re-entered the input compositions to the absorber ?

 

2. Sweetening is a reactive absorption process, so have you entered a reaction set for the scrubber ?

 

3. If you have entered a reaction set for the scrubber, then try changing the column solver method to Sparse Continuation Solver.

 

If possible then please upload your simulation file so we can take a look at it.
Otherwise there are numerous cases where the error might have originated from including human errors like putting the calculation on hold.

 

Regards,

Shantanu

Edited by shantanuk100, 03 December 2015 - 08:28 PM.

[Padmakar Katre]

Hi,

I would suggest to add all 3 solvents all together and just vary the composition of lean amine i.e. when you use DEA put MDEA and MEA as zero.

 

Another issue could be just check the solver if it is on hold?.

[Mahdi1980]

Sherkhan,

It is hard to diagnose exactly your fault. Eachwhere in your simulation it may be happened.

Anyway,please run your program according to the below procedure:

1- run your program just with DEA; select DEA in a new file as just an Amine component and then select the appropriate thermodynamic model and after defining the unit operation and complete the process flow, run the program and see the results.

2- if the results are ok and logical, it means that DEA is not harmful for your simulation and maybeyour software is not original.

   then at this time you can add other components (MEA and ...) and check the result

3- If in the 2nd stage, you still have the problem in running with DEA, the cause likely refers to the thermodynamic model. In such cases, NRTL or uniquac are appropriate.

If you have again this program, please send your file to me to check it

Edited by Mahdi1980, 03 December 2015 - 04:21 PM.

[shantanuk100]

SherKhan,

In addition to the earlier answer I would like to add a few more areas you might want to look into if you are having further problems.

1. As Mahdi pointed out, change the thermodynamic model of the streams and scrubber to NRTL and try the simulation again. NRTL model is generally more suited for liquid property calculations over other models so you might want to try that.

 

2. Try changing all the liquid streams to NRTL basis and the vapour ones to peng robinson so that the properties are accurately simulated. The stream cutters during change of property basis before the scrubbers will be automatically added.

Then use an absorber with a peng robinson basis and check if it converges with the sparse continuation solver.

 

3. SInce you wish to exactly study the effect, you should enter a reactive absorption process so check if you have entered the right reactions once again.

 

Regards,

Shantanu

[Padmakar Katre]

The amine sweetening simulation has to be with thermo package as either amine or DBR amine package in Hysys.

 

What are specs on amine stripper or regenerator? While switching from one amine to another, do you delete the older one?