Help- how to calculate the rate of vaporation capacity of lpg ?

[Ohman]

Dear
I have seek a few documents about calculating the rate of vaporation of LPG, but no more useful answer. It only show the rate of vaporation of propane in various temperature- various volumes. I think it doesnt match to LPG, so anyone have some ideas about this, please help!
My email: ohman2025.OH@gmail.com ( in case you have more documents, and you can share without boring, please share with me)
Thanks and Best regard!

[Ohman]

Help!

[daniwibowo]

What operating pressure do you expect?
What do you want with rate of vaporization of LPG?

[Ohman]

What operating pressure do you expect?
What do you want with rate of vaporization of LPG?

thanks for your reply.
LPG's compressed at 5-8 bar, I want to compare among various temperature and caculate the vaporization of LPG in 100lbs cylinder.
If you have any document about this or you can solve completely, please help me?

[daniwibowo]

Hi...

I think you able to use hysys:
1. Use your LPG component
2. Set pressure 5 barg
3. Set flow 100 lb/hr
4. Use case study with pressure 5 bar g and range temperature you want (i.e 20-100 deg C)
5. You will get vapor fraction of LPG at that pressure.
6. If you need any other opinions pls let me know.

If other member have other answer will be good for all of us

[Ohman]

Hi...

I think you able to use hysys:
1. Use your LPG component
2. Set pressure 5 barg
3. Set flow 100 lb/hr
4. Use case study with pressure 5 bar g and range temperature you want (i.e 20-100 deg C)
5. You will get vapor fraction of LPG at that pressure.
6. If you need any other opinions pls let me know.

If other member have other answer will be good for all of us

I think hysys only show the result not completly usefull in this case.
And in this case I want to caculate the capacity of vaporization of LPG in 100lbs cylinder, not for the flow 100lb/hr.
First we have to find the heat exchange from the environment to the liquid phase through the cylinder. Then according to the three phase and latent heat of LPG we can find the answer. I just seek a liitle bit
If you have any opinion, we can discuss more about this.
Thanks so much..

[daniwibowo]

Hi Ohman,

i saw the same at:

[link Point to another website Only the registered members can access]
use hysys for make P-H diargam basis of your LPG composition.
or use prode if dont have access to hysys

[Ohman]

Dear daniwibowo
I have thought about using hysys but it just show the result when you chose a devices. I know about hysys just a little bit. It's my pleasure if you can show me how to to that.
Thanks so mucn

[carlo.stenali]

Ohman,
yes, you have to estimate heat transfer but for this case you may simply assume a constant value (see Perry or some standard as GPSA for detailed discussion)
then you solve a P-H flash (or use a diagram as suggested by others)
solving a P-H flash (where dH is the heat added at each interval) at regular intervals allows to simulate the vaporization vs. time (dynamic),
you may use your simulator or another tool depending from preferred interface,
for Excel I recommend this

[link Point to another website Only the registered members can access]

[Ohman]

Dear carlo
In hornetly, i want to know how to caculate that.
May be the problem is not clearly. In this case, i want to caculate the flow of LPG flew out the environment from the cylinder 100lbs by natuaral vaporizing among various volumes. Can you discuss more this with us?
Thanks so much

[carlo.stenali]

given composition and initial conditions (P,T)

1) solve a isothermal flash (P.T) to verify initial phase fractions and compositions

2) start dynamic simulation in n time steps

3) estimate heat transfer for liquid phase and calculate dH heat absorbed in time step (dW*area*time step)

3) solve a P-H flash (in some cases, as alternative. you can solve a V-H flash, see 'http://prodesoftwareapplications.blogspot.de/2013/05/how-to-calculate-fluid-conditions.html' )

4) extract vaporized fluid and redefine compoaitions

5) repeat step 3

I solve these problems in Excel with Prode Properties, see

'http://www.egpet.net/vb/threads/27092-Excel-library-for-process-calc-s-including-distillation'

but you can apply the same methodolgy with a different software