7 replies to this topic

[satank]

I tried to run Methane Reforming Based Hydrogen Production by hysys. The reactions are:
CH4+H2O = CO+3H2
CO+H2O = CO2+H2
CH4+2H2O = CO2+4H2
I use Plug Flow Reactor and other reactors. After I complete to put every variable,hysys is showed warning that " K-100 Overspecified "
And in each reactor box is showed " Not Solved ". How to solve this problem?
Thank you in advance.

[joerd]

I tried to run Methane Reforming Based Hydrogen Production by hysys. The reactions are:
CH4+H2O = CO+3H2
CO+H2O = CO2+H2
CH4+2H2O = CO2+4H2
I use Plug Flow Reactor and other reactors. After I complete to put every variable,hysys is showed warning that " K-100 Overspecified "
And in each reactor box is showed " Not Solved ". How to solve this problem?
Thank you in advance.

That question is hard to answer without seeing your model, you may want to post it here, but take out any confidential info.

Assuming that K-100 is your reactor, it looks like you gave Hysys more info than it needs. You typically want to specify inlet conditions, pressure drop, reaction data, and residence time data (or reactor dimensions), but not more than that.

[Padmakar Katre]

Dear Satank,
You can find tutorial for H2 Production or Ammonia Production where these reactions are modeled. If you could tell us more about your model/configuration we could analyze and suggest accordingly. As 'Joerd' said that any unit operation to solve it need minimum inputs to be given by user (In other words the degrees of freedom)and others are calculated by Hysys, so just in case if specify more than required inputs it overrides the value calculated by Hysys so it gives you warning that the operation is 'over specified', by the time the Solver gets inactive and the same operation will warn you as 'Not Solved. So just build your model properly.
I could anticipate the probable reasons as below,
1.Is it an adiabatic reactor i.e. it has an energy stream attached, if not attached and specifying outlet temperature could warn you as over specified.
2.Inputting the DP across reactor(I assume that the inlet feed stream is converged or it has a pressure value)and again specifying the outlet pressure(if it doesn't matches) would give the same warning with solver becomes inactive depicting another new warning as 'Not Solved'.

[satank]

Thank you Joerd and Che Jedi
I try to do my simulation again but still have the same problem.
I study in process control. This topic relates to my thesis.
I would appreciate it if you helped me solve this trouble.

My file is attached to this reply.
K-100 is the first combine.
Despite I put delta P, The first bump of the upper line is still showed "unknown delta P".
The other instruments are showed "not solve".

Attached Files

•  my file.GIF   20.32KB   72 downloads

Edited by satank, 15 July 2010 - 12:32 AM.

[joerd]

Can you post the actual hysys file (.hsc)? I believe Cheresources doesn't let you post hsc files, so you'll have to zip it before posting.

[satank]

Thank you Joerd

Attached Files

•  hydrogen process.zip   61.45KB   116 downloads

Edited by satank, 28 July 2010 - 12:51 AM.

[Dacs]

Thank you Joerd

What I did to make it work:
1. Set all Heat Exchanger pressure drop to zero
2. Removed the composition in Stream 10

Anyway, I think that most probably this is not the system that you want to have in mind, but for the purpose of making it work, the above procedure suffices.

Attached Files

•  HYDROGEN PROCESS.zip   79.41KB   138 downloads

[satank]

Thank you Joerd

What I did to make it work:
1. Set all Heat Exchanger pressure drop to zero
2. Removed the composition in Stream 10

Anyway, I think that most probably this is not the system that you want to have in mind, but for the purpose of making it work, the above procedure suffices.

Thank you very much Dacs