4 replies to this topic

[kobie]

I am a final year student doing my design project on thr production of nbutanol and ibutanol from a feed stram of nbutanal and ibutanol using vapour phase hydrogenation , i am having difficulty getting the hydrogenation of butanal to butanol to converge on a PFR in HYSYS.. i have the kinetic equation for the nBAl and iBAL and also the byproduct

BALS = 2.5*10^4 exp (-3546/T(k)) (Pbal)^0.7*(Ph2)^0.5 lbs butanol/ft3 cat.h
By Prod = 5.4*10^5 exp (-6000/T(k)) (Pbal)^1.8 lbs by prod/ft3 cat.h

not really sure if im using the right fluid pkg..i am using the glycol package on hysys 2006

thankss

[joerd]

You definitely cannot use the glycol package. Probably, Peng-Robinson is just fine for this application.
I cannot tell you why the PFR would not converge, since you provided only very little data. Pay attention to the units of measurement, check your inputs, start with a very short reactor (i.e. very little convergence), are a few things that come to mind.

[kobie]

You definitely cannot use the glycol package. Probably, Peng-Robinson is just fine for this application.
I cannot tell you why the PFR would not converge, since you provided only very little data. Pay attention to the units of measurement, check your inputs, start with a very short reactor (i.e. very little convergence), are a few things that come to mind.

I managed to get it to converge when i varied the molar flowrate of the feeds, but im either get more than 100% conversion or well less tyhan that.

FEEDSTOCKS

BUTYRALDEHYDE

Supply pressure - 6kg/cm2 gauge
Supply temperature - 40©

Composition wt%
Normal Butyraldehyde 90
iso Butyraldehyde - 9
Water - 0.9

HYDROGEN

Supply pressure - 17kg/cm2 gauge
Supply temperature - 40©

Composition mol%

Hydrogen - 95
Nitrogen - 0.3
Methane - 4.7

C12 trimmer - 0.1

What package do you suggest considering the components, i am considering using the UNIQUAC or Wilson package because of the butanol/ water azeotrope, which i doubt can be separated using the peng robinson package...

THanks for your anticipated help

[Padmakar Katre]

Dear,
First thing let me correct you to use the any Activity Coeficient Model like NRTL,Uniquac,Wilson (VLLE not supported) and not any Equation of State like PR. The reason being it is getting solved on varied flow is that probably you are giving the dimensions of PFR in the Ratings Page. Check the accuracy of the modelling of your process else you can go through the documentation by Aspen Tech on PFR.

[farshad]

I am a final year student doing my design project on thr production of nbutanol and ibutanol from a feed stram of nbutanal and ibutanol using vapour phase hydrogenation , i am having difficulty getting the hydrogenation of butanal to butanol to converge on a PFR in HYSYS.. i have the kinetic equation for the nBAl and iBAL and also the byproduct

BALS = 2.5*10^4 exp (-3546/T(k)) (Pbal)^0.7*(Ph2)^0.5 lbs butanol/ft3 cat.h
By Prod = 5.4*10^5 exp (-6000/T(k)) (Pbal)^1.8 lbs by prod/ft3 cat.h

not really sure if im using the right fluid pkg..i am using the glycol package on hysys 2006

thankss

Dear Sir
Im MS student in chemical engineering.
i want simulate nbutanol from nbal.
i see you report reaction rate.
would you please help me to find refrence f this reaction rate.
you can contact me with two email:
farshad_azad1@yahoo.com or
farshadazad64@gmail.com
i have a complete industrial data about butanol palant.if you want i can share this data.

sincerely
farshad azad