5 replies to this topic

[Woopy]

Hello,

 

I want to simulate a biological reaction, but the stoichiometry is not well known. How can I model this using SuperPro? What kind of reactor is suitable? Or for Aspen Plus

 

Thanks

[Lucian Gomoescu]

Hello,

The answer depends on the meaning of  "the stoichiometry is not well known". What is known about the reaction then?

[Woopy]

Great question,

 

right now what is known is the conversion, and the products and starting reactants. The reaction scheme is very complex, so I don't think there is any way to model it using Aspen. I'm still trying to get kinetic data for the reaction. I heard biological reactions can often be modeled as first order, or possibly I can use michaelis kinetics.

 

This reaction has not been studied extensively, that is why not much is known and I don't have all the details. I'm just wondering from a modeling perspective what kind of reactor I can use if I don't have the stoichiometry for the reaction.

[Woopy]

I found some information that gives michaelis-menten kinetic parameters Vmax and Km, so at least now I have something to work with.

[Woopy]

What is the difference between a stoichiometric and kinetic reactor in SuperPro? They both require inputs of the stoichiometry, and I am trying to avoid that

[Lucian Gomoescu]

Until know i can say that it is possible in Aspen +.
As a simple example i used a CSTR for the following typical MM mechanism of reaction:

 

S + E <==k_1/-1==> SE ==k2==> E + P

Which finally, after doing the math with MM assumptions, gives a reaction rate:

 

r = Vmax*[S]/(Km + [S])

, where:

r is expressed in kmol/m3-s;

Vmax=k2*E0, in kmol/m3-s;

Km= (k-1 + k2)/k1, in kmol/m3.

 

The substrate (S) and product (P)  were introduced in component list using the water from databank and changed their ID.

 

The reaction type is 'general' class 'LHHW' in order to allow a rate expression which can be brought to the form we want.

Enzime molar concentration is included in Vmax.

 

For more details you can have a look in the file attached.

 

 

Attached Files

•  BioReact.bkp   28.34KB   5 downloads