Hydrogen pressure-swing purification using Aspen Adsorption 2/2
ฝัง
- เผยแพร่เมื่อ 23 มี.ค. 2020
- Simulation of a breakthrough experiment and basic PSA cycle (2 beds, 4 steps) to purify a H2/CH4/CO gas. Software by Aspen Tech Inc. Common mistakes and basic troubleshootings reviewed.
Other references:
Lee & al., 2008 (doi.org/10.1002/aic.11544)
Xiao & al., 2015 (doi.org/10.1016/j.ijhydene.20...)
DISCLAIMER:
these workshops are organized freely and made for free; they are not part of a regular course.
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Very helpful! Grazie Antonio!
Hey Antonio! I left a comment on your first video earlier this week and it was very helpful! I am now stuck here. When I try to run stage 2 of the process (where the input valve to Bed1 shuts and Bed2 is desorbed into the waste stream), the process will simulate for 7 seconds, at which it fails to an integrator error. I tried to force the integrator to converge by changing the number of steps to check, but it did not work. Do you know what other things I could try? Thanks!
Thank you so much for your detailed video
1) When the valve is set to 3 = use the specified flow value (constant flow), when constant flow, what is the relationship between Cv value and Flowrate?
2) Is the value of Δp the difference between the two sides of valve? Δp calculations have always bothered me ！
I thank you so much for your precious time.
Hallo.
1) when a valve is in mode=3, the Cv value has not any importance.
2) the aspen model is Flow = Cv*dP, where dP is actually the pressure drop across the valve.
Hi, Antonio, a very helpful video. I just wanted to ask what are the numbers 2 0,07, 2 2e-6 in the Excel sheet when you start listing the valves.
Number 2 means "CV mode"; the other numbers are the CV values, in the Linear approximation, ie CV=flow/(Pin-Pout)
I have a question. In this case u used literature design parameters (number of adsorbers, valves Cv, cycle time and so on). How i can get initial parameters for H2 PSA in the other case (for ex: number of adsorbers in the case 80% recovery or 85, 90, or amount of adsorbents (zeolite, carbon))?
Can i calculate it? Or not?
Thank you, Pureté H2 = mole fraction in the product stream =0,59 Why is it low? Am I wrong? Can you help?
Hi Antonio. Thank you for this informative video. After adding the Cycle Organizer, I received this error message: "Initialization failed at time 0". Do you happen to know how to fix this and troubleshoot the flowsheet to see what's not working?
If you get this error ONLY after adding the Cyc Org, then most lilekly you mistyped some valve opening/closing status.
Another possibility is that the beds are not initialized at the correct pressure, or with the correct gas.
@@Antonio_Tripodi Thank you!
Thanks for the wonderful video. The question is, how do I calculate the purity of hydrogen? This is the case
It is the mole fraction in the product stream
Thank you for your video, very helpful, can you share your simulation software files
Hallo. I encourage you to build your own custom simulation. Good work!
Thank you so much for your detailed video :) I have better ideas how to use the software now. By the way, may I ask some insights about Isotherm? For example, Toth isotherm eqn is based on partial pressure only so how do I indicate temperature dependency of the isotherm in Aspen Adsorption? I thank you so much for your precious time.
In general, if you have a model doesn't account for the temperature, you ought to:
1) fix the temperature of your simulation at the values for which your data are validated;
2) check how the temperature dependecy is modeled in Aspen;
3) fix to zero the coefficients that describe the temperature effect.
For example, in the Langmuir formula, Aspen requires: c_sat = a*[b*exp(c*T)*P]/[1+b*exp(c*T)*P]
if you have data for a single temperature value, you can set c=0, provided b has the value to correclty describe your isotherm.
@@Antonio_Tripodi Thank you so much for your kind replies.
Amazing work of your simulation! I have a question, I tried to make a simulation like this with 2 beds on oxygen PSA, but when I try to run it, there is a message "A sub-group in the decomposition failed to solve", do you know something about this error? thanks by the way
This error can come out either with not correct inputs or with a non-consistent problem setup.
Usually the most common causes are: incorrect adsorption isotherm; incorrect flow-rate / pressure-drop management; but there can be also athers.
@@Antonio_Tripodi Thanks!!
hello Kobe
I hope you reply to message...
can I ask you something about the oxygen plant simulation?
Since long I was searching for some videos on PSA simulation. Thank you for such an informative video.
can you please explain how to calculate Cv of the valve and on what basis you gave 0.08 as the value of Cv of waste gas valve
In general, the Cv of a valve is such that: FLOW=Cv x dP^2. In Apen Adsorption, however, it is assumed a simplified relation: FLOW = Cv x dP, where dP is the pressure difference across the valve.
The number in this simulation was calculated in order to have roughly a waste of 1/3-1/2 respect to the product.
This depends on the relative amount of the different gases in your feed. E.g., if your feed is 50%-50%, the product and the waste will have to carry away the same flow, so their Cv will reflect the different pressure condition at their discharge.
Remember that the actual flowrate across the valves is strongly influenced by the adsorption/regeneration taking place in the beds.
@@Antonio_Tripodi thank you. Can you please make a video for TSA process
could you please make clear how 0.08 was calculated? thanks in advance
What do U think about gProms?
How can you increase the flow of your system to something more common? Because it is around 0.1 mol/s and if we convert that to m3/s it is a very small quantity
The flow is very small because, to keep close to the reference paper, a lab-scale test was reproduced.
If your goal is to simulate an industrial plant, you have to work on the right system size from the very beginning, when you add the first bed and the first valve.
Sorry , but if we change the FEED Pressure will it effect on the prodect ( product composition ) ?
Generally, YES. But it depends on the adsorption characteristic of your solid.
Thanks for your generious response I’m working on Flare gas recovery using PSA technology
But im facing problems in simulating in calculating CV and also the langmuir parameters for the hydrocarbons
@@amrmoh9382 If you need further assistance you can mail me
I did thanks alot
hi
is there anything that explains the simulation of oxygen production by adsorbing N2?
Not on my channel sir.
If you browse the web carefully, you should come across a couple of pdfs.
@@Antonio_Tripodi unfortunately it's been months since I began searching but nothing is really that helpful, there is always a problem I stuck at.
pressure swing adsorption is what I'm looking for.
@@gio-vy9ge i have been working in engineering company with N2 and O2 PSA (real units). But i never worked with H2 PSA. Many years im trying to understand how i can calculate H2PSA.
I'v done Aspen Adsim model, but the results of simulation are not so good (compare with UOP calculation file).
Awwww. I understand U
@@user-wq8ro7pg1n thank you for replying...
can I talk to you a little about it? I won't take much time I promise
@@gio-vy9ge yes
Anyway like :)
i am working on oxygen seperation from air via Pressure swing adsorption. Could you please help me?
is there a specific problem?
@@Antonio_Tripodi I never used aspen adsorption before so will it be possible if you advise me any video so that I can start simulation of oxygen separation from air using aspen adsorption?
@@salmanshahid611 you should look in the literature for the isotherms of a suitable material, then you can try ti follow the procedure that I followed for my gas
can you provide me a link of paper Im also doing my thesis on PSA hydrgen purification
I've added the link in the description. There are hundreds of papers on hydrogen PSA, expecially when the gas is a reformate, so often one has to made cross-checks and look carefully at the general conditions described in the literature (not any paper really fits the scope of your work!). Regards
@@Antonio_Tripodi thank you for your kind respond i will be careful..if i need a help will you help me?