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Questions about Heterogeneous Equilibrium Reactions, Matrix composition, Reactor domains
Posted Jul 6, 2011, 10:19 a.m. EDT Chemical Reaction Engineering Version 4.1 1 Reply
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After a lot of searching and reading (this site, google, documentation) I still haven't found the answer to three important questions that I have. I'll just get to the point:
1) Is it possible to use (only) COMSOL to do heterogeneous equilibrium reactions (solid/gas) and if so, how?
I want to use an equilibrium model to describe devolatilisation and combustion in a reactor with a packed bed of wood particles. The only possible options I can find (in "Reaction Engineering", under "Mixture") are gas or liquid.
As I understand 'Chemkin' is also not capable of this.
2) Is it possible to assign a composition of materials to the porous matrix in the "Species Transport In Porous Media"? I really see no way to couple this yet, one cannot simply pack some materials together as one material and assign this to the matrix. Well, maybe you can (by averaging the properties), but it won't work for me. I need to materials to act as containers that keep reacting until they are empty in both a proximate (water, volatiles, char, ash) and elemental (C, H, O, Inert) way.
3) What is the best way to describe (50) virtual zones or slices (of a packed bed) that react in series; a continuous flow through porous media, or virtual reactors (CISTRS) in series that are somehow linked to every 1/50th domain (how indeed, since there is no option to 'link' a ''Reaction Engineering'' model directly to an actual geometrical space that I know of yet).
Some more background might help to understand what I would like to accomplish:
My goal is to build a model in COMSOL that emulates a real life reactor in which a bed of wood particles is ignited from below using hot air and combusts from bottom to top. The idea is to divide the height (1 m) into 50 virtual zones in which equilibrium reactions calculate the outgoing gas composition (per zone) with temperature, kinetic rates and old composition as input. It is basically a series of 50 CSTR's but the heterogeneous reactions confuse me when it comes to COMSOL. I am a beginner though, and I know this is probably not the easiest stuff, but I really need to know this..
I'm sorry it is quite a lot of text and questions, but I am really getting nowhere.
I would be VERY grateful if anyone would be so kind to give up a little of his or her valuable time to give me a hint..
So, thanks in advance, even for just reading it, and I very much hope someone can help me.
Thank you and kind regards,
Raymond
1) Is it possible to use (only) COMSOL to do heterogeneous equilibrium reactions (solid/gas) and if so, how?
I want to use an equilibrium model to describe devolatilisation and combustion in a reactor with a packed bed of wood particles. The only possible options I can find (in "Reaction Engineering", under "Mixture") are gas or liquid.
As I understand 'Chemkin' is also not capable of this.
2) Is it possible to assign a composition of materials to the porous matrix in the "Species Transport In Porous Media"? I really see no way to couple this yet, one cannot simply pack some materials together as one material and assign this to the matrix. Well, maybe you can (by averaging the properties), but it won't work for me. I need to materials to act as containers that keep reacting until they are empty in both a proximate (water, volatiles, char, ash) and elemental (C, H, O, Inert) way.
3) What is the best way to describe (50) virtual zones or slices (of a packed bed) that react in series; a continuous flow through porous media, or virtual reactors (CISTRS) in series that are somehow linked to every 1/50th domain (how indeed, since there is no option to 'link' a ''Reaction Engineering'' model directly to an actual geometrical space that I know of yet).
Some more background might help to understand what I would like to accomplish:
My goal is to build a model in COMSOL that emulates a real life reactor in which a bed of wood particles is ignited from below using hot air and combusts from bottom to top. The idea is to divide the height (1 m) into 50 virtual zones in which equilibrium reactions calculate the outgoing gas composition (per zone) with temperature, kinetic rates and old composition as input. It is basically a series of 50 CSTR's but the heterogeneous reactions confuse me when it comes to COMSOL. I am a beginner though, and I know this is probably not the easiest stuff, but I really need to know this..
I'm sorry it is quite a lot of text and questions, but I am really getting nowhere.
I would be VERY grateful if anyone would be so kind to give up a little of his or her valuable time to give me a hint..
So, thanks in advance, even for just reading it, and I very much hope someone can help me.
Thank you and kind regards,
Raymond
1 Reply Last Post Jul 11, 2011, 11:00 a.m. EDT
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Posted:
1 decade ago
Can anyone just please tell me if it is possible to model solid/gas reactions? The only option under 'mixture' is either liquid or gas which are both without the solid option. Can it be done? I really need to know. Many thanks for any info.
Ray
PS.
I know about the tortuous reactor example model in which the reactions are contained to certain surfaces, but this is not a true heterogeneous reaction, it is just a liquid/liquid reaction on a certain area.
Please.,...help.
Ray
PS.
I know about the tortuous reactor example model in which the reactions are contained to certain surfaces, but this is not a true heterogeneous reaction, it is just a liquid/liquid reaction on a certain area.
Please.,...help.