2 replies to this topic

[skyicetel1]

I've made amine gas sweetening process and almost done.

but, there is a problem of estimated stream and actual stream.

 

When I started to make it, I made absorber and regenerator separately.

 

first, I estimated 'lean amine feed(S3)' by using  'specification and variables' at absorber.

 

After finishing regenerator, I tried to use actual 'lean amine feed(S17)' instead of S3.

 

unfortunately, every streams turned red after running(stoichiometry error)

can I get some advice?

 

I attach pro/ii file with google drive, please refer to this

 

https://drive.google...iew?usp=sharing

Edited by skyicetel1, 20 May 2022 - 08:21 PM.

[Pilesar]

Recycles in steady state simulators can be tricky sometimes. Usually, the composition from the stripper will give the CO2 loading for the lean stream and the flow rate is set by the absorber specs. You don't have to necessarily close the loop in the simulation as long as you get the answers you are seeking. Your file did not attach, but I suspect you may be losing a slight amount of amine out the top of the stripper and you are not providing any makeup amine to the system. What looks like negligible losses in an open loop may spiral down after many iterations in a closed loop to nonsense. When the simulator tries to force a material balance, the steady state solution cannot be found. There are tricks to closing a recycle loop, but I suspect it would be a great waste of your time when you can find a good enough solution with the open loop. Try using the S3 feed stream that works and then changing its composition by hand to match the S17 stream for one manual iteration and see if it makes any real difference to your solution.

[skyicetel1]

Thanks pilesar, I will try it. always helpful