Looks like you are at odds with stoichiometry.

Mirosław Grzesik

Thank you very much Mr. Miroslaw. Do you know if there is another way that I can model biomass pyrolysis to the former products without using intermediate reactions, i.e reactions that give in general gas,char and tar?

Hi Pavlos Kostopoulos ,

(1)Did you have any kinetic data available for biomass pyrolysis?

(2)According to your questions, you want to model it to account for Biomass ==> CO2+CO+H2+H2O+CH4 without any intermediate?

Pavlos Kostopoulos Results of TGA/DTG studies for Biomass pyrolysis will come in handy in determining the detailed kinetic model of this thermochemical process (Conduct a literature review). Then it is about incorporating the kinetic model in the coupled mass and energy conservation balance for the RCSTR reactor (I presume the process is endothermic) and simulating for prediction of product (bio-oil, tar, char) formation.

NB: The final product composition will vary dependent on the pyrolysis rate

The description of thermal decomposition of biomass, even at the stoichiometry stage, is difficult and ambiguous. Either you search for data in the literature or you do the research yourself.

Shrinking core kinetic model-Heterogeneous phase reaction system in this case

The use of the Gibbs reactor model in Aspen Plus/HYSYS does not require much data for it to predict the product based on the thermodynamic condition of the process. You are not expected to provide a reaction set instead, you are to provide all possible compounds that is expected to participate in the process. The simulation of the model is expected to predict the distribution of the product based on thermodynamic conditions provided in the modeled process.

Check it out Pavlos Kostopoulos

To add to the good suggestions-Gibb's thermodynamics equilibrium calculations predict the maximum possible extent of reaction. In other words the amount of reaction that occurs at infinite reaction (residence) times, This assumes that the reaction is very fast.

But if the reaction is not so fast, then mass transfer, heat transfer, chemical kinetics and reactor input determine the final reactor output=> Reactor Performance Equation (CSTR model , PFR model, Batch Reactor model, Kunii-levenspiel's bubbling bed model for fluidized bed reactors)

Hello Toyese Oyegoke and thank you very much!

1) Yes, the kinetics for each individual reaction are available.

2) Truth is that I have done it with a Rgibbs reactor and it is a quite convenient choice. If I wanted to model the pyrolysis in a kinetic manner, how could I model it in Aspen by using a single reaction, like that you have written, with a kinetic scheme?

Thank you for the advice Mr. Mirosław Grzesik . I will keep that in mind.

Thank you very much for your help Mr. Karinate Okiy

1) I would like to ask you if you could suggest where could I find trustworthy literature data of DTA/TGA analysis.

2) Have you modelled such processes in Aspen Plus? In general, the directions you have given me are right, but I have issues in implementing them in Aspen, especially if the use of user models(external Fortran code) is necessary.

Pavlos Kostopoulos I have not modeled Biomass combustion or related processes in ASPEN Plus before. Just from thermodynamic considerations, Gibb's free energy minimization yields the equilibrium (most stable) state for a reaction system.

If you give me an email address, i can send you the kinetic data for simulating the reaction in Aspen Plus or any other process simulation code

Yes of course Mr. Karinate Okiy

My email address is [email protected]