What is the pressure inside the LPG cylinder vessel used for domestic cooking

Thank you all for answering my question.

I am from India. As per IS:4576 (indian standards) code for LPG Specification. In that the vapour pressure of propane and butane have been given as 1550 kpa for propane and 520 kpa for butane at 40 degree celsius. I am giving below my calculations, Please let me know whether the calculations are right or not.

Total vapour pressure of a mixture = partial pressure of vapour 1 + partial pressure of vapour 2

As I told in my question, the mixture contains 70% propane and 30% butane.

So the pressure of LPG mixture = (0.7 x 1550) + (0.3 x 520) = 1241 kpa

Converting it into bar, 1241 kpa = 12.41 bar @ 40 degree celsiuis.

Hence the pressure inside the cylinder will 12.41 bar @ 40 degree celsius.

Please let me know whether the above calculation right or not.

Thanks in advance,

The pressure is self regulating! You compress the gas and it liquifies - if you compress the liquid then the bottle will burst otherwise it depends upon vapour pressure! You cannot incease the pressure inside the bottle as long as their is a vapour space. Over the critical temperature then it is another story!!!

Thanks Tesser,

This is what I wanted. Thanks again for very detailed answer.

Excellent, well thought out & accurate answer. It's refreshing to hear from a true professional !

good. keep it up.

with my experience in a lpg plant in honduras, i see the manometers in the place of refilling, the pressure are 150 psi to 5 galons cilinder, and others is equal.

i hope my info will be good for you.

This a liquified gas - very little pressure is needed to get below freezing.

I have had this question as to what happens to an aerosol can (with lpg propellant) when it is heated.

Vapour pressure matters until above critical temperature - I believe it will then be a compressed gas and pressure will increase. This is what happens when you have a BLEVE (Boiling Liquid Expanding Vapour Explosion)

Non sequitur !

Greetings.

Use a manometer to get an accurate reading of output.

I believe 27.71 inches of water column equals 1 pound per square inch.

Pressure at about 70 deg. F is about 225 PSI. higher with higher temp. lower with lower temp., The outlet of the regulator is held at about 11 inches water column.

You "failed to follow through". Are these just pretty words, because that's what has been expressed! What regulator are you referring to? If it's in the contex of the original question, you are in error by roughly 220% ! The LPG manufacturer worker may be able to confirm this; the bottle outlet is 10 psi + - 1.5 psi.

What am I missing in the following;

Propane/LP Gas

All propane and LP Gas applications require the use of a regulator. Because pressures in propane tanks can fluctuate significantly, regulators must be present to deliver a steady flow pressure to downstream appliances. These regulators compensate for tank pressures in excess of 200 psig and commonly deliver 11 inches water column for residential applications. Propane regulators differ in size, delivery pressure and adjustability but are uniform in their purpose to deliver a constant outlet pressure for downstream requirements. As is the case in all regulators, inlet pressure is higher than outlet pressure.

from wikipedia,

11" water gauge is the usual working pressure for LPG domestic appliances. It is not the standing pressure.

The pressure at the regulator outlet is quite a bit higher (sorry I have gotten what the actual pressure is) to allow for multiple outlets to be used at once and loss of pressure through drag through the pipework etc. All appliances should also have their own regulator to allow finer adjustments if required.

cheers,

Terry

that is equal to around 10 bar that is vapour pressure of 70 + 30 butane and propane. vapour pressure is that pressure at which lpg transforms to vapour form from liquid foam.

So what maximum pressure can LPG vessels cope with then ?

DCB

http://www.teecoproducts.com/catalog/A11.htm

we are working on the topic of LPG cooling we need the temp. & pressure inside & outside the cylindr while working ,please reply me to www.suyogpatil.mech@gmail.com