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Entering Data Into Aspen

aspen reactions pseudo-species

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#1 Carlos Reis

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Posted 18 October 2014 - 02:12 PM

URGENT

 

 

Good evening,

 

Regarding the multistep kinetic scheme of biomass pyrolysis, I must to introduce in simulator Aspen Plus the following reactions:

 

G{CO2}  → CO2

 

G{CO}  → CO

 

I think G{CO2} and G{CO} components are pseudo-species and I don´t know which is the method for doing that on Aspen. 

 

 

Thanks in advance

Carlos Reis



#2 AlertO

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Posted 20 October 2014 - 03:17 AM

Hi Carlos

 

First you can start with create hypo-componets for your G(CO2) and G(CO). This requires the actual MW, boiling point and density. After finishing hypo-component generation, you will have 2 new components for using in your reaction. 

 

Next, you can go to the reaction section. In ASPEN (not sure which Aspen you use: hysys or aspen plus), there are many reactor types e.g

RSTOIC, RYIELD, RBATCH, RCSTR, etc which require different input as well as the accuracy of the output. You have to choose what input do you have and then matching with the reactor in the program. The difficulty of this step depend on your reaction complexity.  If your reaction has a very complicated machanism, you need to select the rigurous reactor model e.g. RBATCH, RCSTR.

 

Hope this may help you



#3 Carlos Reis

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Posted 21 October 2014 - 09:53 AM

So many thanks for your reply!

 

I will try it and then I update you.

 

I´m going to use an RCSTR in Aspen Plus.

 

Thanks, Thanks, Thanks,

 

Carlos



#4 Carlos Reis

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Posted 24 October 2014 - 06:40 AM

Hi, AlertO,

 

But how can I generate hypo-components if these components are hypothetical and I don’t know the characterization inputs (MW, boiling point and density) for them? I cannot invent them.

 

Carlos



#5 PingPong

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Posted 24 October 2014 - 07:35 AM

Generating components based on only MW, boiling point and density is only applicable to petroleum fractions, not to just any other compounds.

 

Apart from that I doubt that anybody here understands what compounds are meant by G{CO2} and G{CO}



#6 Carlos Reis

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Posted 25 October 2014 - 11:50 AM

Sorry about that, I will explain better,

 

I must input in RSCTR more or less 20 reactions, and four of them are like these:

 

 

HCE → 0.4 G{H2 } + 0.25 H2O + 0.75 CO2 + 0.05 HCOOH + 0.7 CO + 0.15 G{CO} + 1.3 G{COH2 } + ……

 

G{H2 } → H2

 

G{CO } → CO

 

G{COH2 } CO + H2

 

 

Note: HCE is Hemicellulose (from biomass products)

 

 

So, how can I input these four reactions considering the mentioned "pseudo-components"?



#7 PingPong

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Posted 25 October 2014 - 12:27 PM

HCE is not a petroleum fraction, but a solid polymer, so I don't see how you can define that as a pseudocomponent defined by MW, boiling point and density.

 

I am still not sure what you mean by G{CO}

Does it simply mean Gaseous CO, or what?



#8 PingPong

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Posted 26 October 2014 - 05:20 AM

This report from the National Renewable Energy Laboratory (NREL), although quite old, may be of help to you how to include components like cellulose in Aspen Plus:

http://www.nrel.gov/...i/old/20685.pdf

 

I have not used Aspen Plus since 2001 so I can't help you any further.






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