7 replies to this topic

[bacce]

Dear all,
As mentioned in topic title, Im having trouble in selection of a suitable fluid package. My components are benzene, maleic anhydride, carbon dioxide, nitrogen, oxygen and water. When I followed Seader's recommendation, it advised using PSRK, however it turned out that HYSYS does not recommended using it due to the present of Maleic Anhydride. When I followed Carlson's recommendation, I was advised using extended NRTL. Using NRTL seems to be fine at first, however I found out that my packed bed reactor gave no conversion at all. (My reaction is kinetic type, and I noticed that the reaction phase is gas phase). So now I am really confused and dont know what fluid package to be implemented. I would very much appreciate if any of you could give me some advice about this.
Thanks in advance.

P/S: I am using HYSYS

Edited by bacce, 26 September 2009 - 01:33 AM.

[Padmakar Katre]

Dear,
Could you just elaborate a a little more about what you said is Extended-NRTL worked fine at first (Tell us the other Unit Opertaions/Processes you handled in simulation found good results.).Second thing to know is have you defined your reactions in rections tab of simulation basis manager window before you enter in simulation environment. Waiting for your comments.

[bacce]

Dear,
Could you just elaborate a a little more about what you said is Extended-NRTL worked fine at first (Tell us the other Unit Opertaions/Processes you handled in simulation found good results.).Second thing to know is have you defined your reactions in rections tab of simulation basis manager window before you enter in simulation environment. Waiting for your comments.

Dear,
Thank you for your reply.
Actually what I am doing is to design a packed bed reactor for maleic anhdydride production using benzene as starting material. So what I have is just a feed stream containing air and benzene, a PFR and product stream. I have defined my reaction package as kinetics reactions with a main reaction and two side reactions. For the NRTL extension, what I did is to choose the NRTL package and click on All Unknowns button then all binary coefficients of the compounds popped up except for the Maleic Anhdydride interaction. And that's just it. When I defined my PFR with dimensions and catalyst information, the bottom bar is green but I got no conversion. Do you have any idea about that ?

[joerd]

It looks like your reactor operation is converged, but there is no conversion, which means that there is not enough time to complete the reaction, or the reverse reaction is much faster than the forward reaction. Check your kinetics and reactor parameters, especially the units of measurement that you are using, and the residence time.
If all else fails, you can try posting your simulation here, and see if someone has time to look at it.

[bacce]

Thank you
The problem has been solved. It is just because the feed temperature is too low for reactions to happen. It seems there is nothing wrong with the fluid package.

[Padmakar Katre]

Thank you
The problem has been solved. It is just because the feed temperature is too low for reactions to happen. It seems there is nothing wrong with the fluid package.

Dear,
Good to know that you got the results. But make sure the authenticity of the results as you mentioned in your earlier post that the Maleic Anhdydride component have unknown acivity coeffcients. Good luck.

[alex.gutu]

Thank you
The problem has been solved. It is just because the feed temperature is too low for reactions to happen. It seems there is nothing wrong with the fluid package.

Hy Mr Bacce,

I have to simulate a maleic anhydride production unit using bezen as raw material.
I just want to ask you what fluid package have you used finally.

Also I want to ask you how many reaction have you defined in your simulation. As far as I know, there a one or 2 undesired reactions which leads to a secondary product that results from reactor.
I just want to know if you defined only the main reaction (in which results only maleic anhydride), or also you defined the secondary reactions.

Thank you in advanced sir!
Alex

[Ikenna]

Hey Pals,

I am very much delighted on how this problem was resolved.

Please I need help on my plant design 'Chlorine Recovery from Hydrogen Chloride'

I need guidance on how to go by this work. If you have any file (Hysys, Pro II or any) on this work, i would really appreciate.

Thanks.