Langmuir-Hinshelwood-Hougen-Watson (LHHW) Kinetics || Aspen PLUS
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- เผยแพร่เมื่อ 5 ต.ค. 2024
- This video is about the simulation of the Langmuir-Hinshelwood-Hougen-Watson (LHHW) Kinetics in Aspen Plus. The reactor model is simulated with these kinetics.
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Hello, first of all thanks for the Videos. But i dont understand why the B term of k1Kb1is positiv, shouldnt ist be exp(-2645.97/T) im really confused
Thank you for pointing out the mistake. The value should be -2645.97.
Thank you for this! Helped alot, don't usually subscribe but this video was worth it.
thank you
Thank you for the video. It is very helpful for me.
Glad it helped you.
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Sir, you saved my life. Huge thanks ❤❤❤❤❤❤❤❤❤❤❤
Glad to hear that
Hi, thanks for uploading this video
I used this LHHW model with Rplug to adapt SMR process, but there isn't no reaction(convergence rate is zero).
could i know what
's the problem?
Thanks for video, and save my final report!!!!!!!!!!!!!!!!!!!!
Glad it helped.
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@Chemiopedia Thank you for making this video. I wanted to ask you a question. At 4:41 you taught us about term 1 and term 2. My question is that do I need to include that minus sign between term 1 & term 2 with the k1 x Kb1 part of term 2? Should I multiply that minus sign with k1 x Kb1 and then take natural log? Thank you in advance!
Hello, first of all thanks for making the Videos.but im confused about Why did you choose to set k and E as 1 and 0, instead of using k1 as the kinetic factor for LHHW? and simulation result of these two inputs are different
Hello, thanks for the insightful video you ve made. I have also a question about B coefficients for adsorption kinetic constant. Shouldn't be B=-Ea/R instead of B=Ea/R? B constants seem to keep the same sign with their perspective energies.
Hello,
B = -E/T in actual as you mentioned. If E is -ve value (as -4413.76) then the sign of B will be positive which is opposite to energy. If you still confused for any specific term you can ask.
Also read the pinned comment.
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Can you do a similar example for water gas shift reaction?
Thank you for your comment.
You can follow the same method to calculate the A and B for WGS if you have the kinetic data. If not, write to us at chemiopedia@gmail.com for the data.
What happens If for the kinetics you are given the ln of K equilibrium term and that has some T^2 and T^3 terms. Those ABCD in the driving force do not account for that
Do you have any example? If yes, please share support@chemiopedia.com
Hello! Your videos are very educational. Do you have any videos on using the Aspen Custom Modeler integrated with Aspen Plus for more complex kinetic considerations, such as Fischer-Tropsch?
At the moment, I don;t have any videos on Aspen Custom Modeler.
Hello, thank you for the video, but the term k1Kb1 isn't k1/Kb1 (model of Vanden busche and Fromen) i really can't understand this
Thank you !
Thank you for your comment.
I am not sure about this as the kinetics is taken from a book without any further research. The source of these kinetics is not available in the same book.
Could you maybe delay the endscreen a bit more? you can not see the results for your methanol production, my methanol production is only 4 % of the product flow, this seem verry low to me from what i red from papers. What is your production?
In a paper from van bussche and froment i saw that the b value for the second term was appoximately the negative value of what you used, while all other value's where approximately the same, do you know what is correct and why?
The end screen has been adjusted.
if we didnt have energy values for k1 and kb1, what would we have done? would we have considered E to be 0 in those cases? kindly answer asap
(@7:58):
In Adsorption Term 1, Coefficient A should be 1 not 0, right ? Otherwise, the first term in the denominator would be 0 not 1.
I am afraid no.
Consider some K instead of 1 and K = 1 x exp(0/T). By taking LOG,
LOG(K) = LOG(1 x exp(0/T) = LOG(1) + 0/T = 0 + 0/T. Hence, A=0 and B=0.
@@Chemiopedia ohhhhh you are right! Ok, thank you for your help.
Hi, thank you for sharing this useful video. Could you please share how to calculate the second term of adsorption. Thank you
Thank you for your comment.
I am getting lots of queries about this. I am making a separate video on this and will be uploaded in coming week.
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@@Chemiopedia Thank you...Looking forward to it.
Is the LH mechanism the same as the LHHW mechanism?
Hi there, thank you for the video but I'm a bit confused: how did you get the values of k and pre-exponential and also in aspen you put E as 0 but in the video the value of E/R is not 0. can you please show me this part. I'm still learning this section
Hello Martin,
There are two different terms in the numerator, kinetic factor and driving force expression. The whole kinetics is defined in second term. I put the value k=1 and E=0 just to make the kinetic factor =1. Otherwise, it will affect the rate values.
Thank you very much for the video. It is very informative. I followed the same things as you did but I am getting results with errors. Why do you use CO in the stream, even CO is not available in the reaction?
Could you please provide me the paper link, which you have followed in this study?
Can you write us on: support@chemiopedia.com
@@Chemiopedia sure!
Do you have an idea how use submodels in aspenplus?
I am currently trying to impelement a LHHW-kinetic in Aspen but its for reactive distillation (Ratfrac), so LHHW cant be chosen. AspenSupport provided me an example but I struggle getting it working properly for my case.
Sorry don't have any experience of sub models or sub routines. LHHW kinetics in Aspen Plus can only be input as sub routine for reactive distillation.
Hello, thanks for the video, it is great! I have a doubt. In my case I need to put a rate of reaction (LHHW) that is divided into two parts: R1= (k1a.Pch4.Po2)/((1+Kch4.Pch4+Ko2.Po2)^2) + (k2a.Pch4. Po2)/((1+Kch4.Pch4+Ko2.Po2)^1). How can I get the kinetic parameters in Aspen Plus?
I once think the same about this kinetics. But didn't get the chance to validate this assumption.
@@Chemiopedia Thanks for the answer. If you find out how to do this, please let me know! I'm trying to put in Aspen PLus the rate of reactions (R1 to R4) that appear at time 5:35 of the "Generalized Langmuir Hinshelwood Hougen Watson (GLHHW) | Aspen Plus" video.
@@gabrieladefrancalopes1796 i think you can put the same reaction twice in aspen and put first part of kinetics for one reaction and second part of kinetics for second reaction
Hi Chemiopedia, thanks for making this video and it is of great use. I am trying to simulate something similar, but I am facing an issue of finding the activation energy. Is there like a source for these values?
Thank you sir for the video. Could you make a video on how to model an adsorber or a membrane reactor in ASPEN PLUS?
Thank you for your comment.
Aspen Plus does not have adsorber or membrane reactor in model library. These types of units can be modelled in Aspen Custom Modeler. I will look into it and see if I can make a video on it.
I would appreciate it if you could help me get started with ASPEN CUSTOM MODELER
One more thing, May I know from where you have taken the kinetic parameters as it will help me in my project. I am currently working on simulation of methanol steam reforming
I took them from a simulation book.
That book does not have any reference.
@@Chemiopedia can you tell me the name of the book from which you have taken the data?
you can also mail me at (mahfuzahmedm123@gmail.com). Thanks in advance :)
thankyou
Hi, can you share paper from you get these kinetics
Is there a possibility that you would obtain different results for the same simulation on different versions of aspen plus? Given that the same property method is maintained.
Yes. It is possible.
In the latest versions Aspen tech modifies the intersection parameters as well. This can alter the values a little bit.
@@Chemiopedia Alright, thanks for the explanation. Really appreciate it.
@@nanayyaw622 Thank you and don't forget to subscribe.