Compressed Gas

Dear Seniors,
1. How much cubic meter gas present in N2 cylinder?
2. is it mentioned anywhere on cylinder?
3. How to check exact cubic meter of gas present in cylinder at the time of receiving cylinder?
4. How to calculate (Conversion factors) exact cubic meter of gas present in cylinder by taking before use and After use weighing of cylinder (Unit :Kgs )
Regards
Abhay

Dear Abhay,

Please refer Gas Law.

P1V1 = P2V2.

For the simplicity I could get the information from Internet.

Volume of Compressed Gas in a Cylinder

To find the volume of gas available from a compressed gas cylinder, we apply the Ideal Gas Law (PV = nRT). In a high-pressure cylinder, the volume will be affected by the content's compressibility factor Z (PV = ZnRT). For example, an AL cylinder of pure helium may contain 134 cu. ft. of gas while the same cylinder of pure air may contain 144 cu. ft. under the same conditions. For these practical calculations, however, we assume ideal gas behavior for simplicity.

The Ideal Gas Law PV = nRT

Where:

P is pressure

V is volume

n is the number of moles

R is the gas constant

T is the absolute temperature

When the temperature is kept constant, we can derive the equation:

P(1) x V(1) = P(2) x V(2)

Where:

P(1) is the pressure of the compressed gas in the cylinder (psi)

V(1) is the internal volume of the cylinder, often referred to as water volume (liter)*

P(2) is the atmospheric pressure (1 atm - 14.7 psi)

V(2) is the volume of gas at pressure P (2) (liter)

For example, an AL sized cylinder is filled with nitrogen at 2000 psi. What is the gas volume of nitrogen from the cylinder?

P(1) is 2000 psi

V(1) is the internal volume of AL cylinder 29.5 liter*

P(2) is 14.7 psi

V(2) is the unknown volume of gas

Solving the equation above for V(2) gives:

V(2) = [p(1) x V(1)]/P(2) = (2000 psi x 29.5 liters)/14.7 psi = 4013 liters

(approximately 140 cu. ft.)

Alternatively you may please ask your supplier how the measurements are done.

Try to locate if this falls under any IS code, and read the Receiving Inspection Methods.

Please revert back in case you do not get satisfactory answers.

By then I shall ask the Design Engineers.

Thanks & Regards,

Sudhir

Dear Sudhirji,
Thanx for all technical explanation .... But sorry to say that I hv not got exact answers for my query. If you don't mind kindly ask your design engg. Waiting for your kind reply.
Thanx & Regards
Abhay

Dear Abhay,

I tried to clear your queriesas per your questions. Please gothrough the same. Hope may clear your queries.

1. How much cubic meter gas present in N2 cylinder?

 Approx volume of N2 Cylinder is 50 Litres.

 Pressure in N2 Cylinder is about 150 Kg/Cm2.

 If you apply Ideal gas law P1V1=P2V2 → 150x50=1xV2 →V2=7500Litres.

2. Is it mentioned anywhere on cylinder?

 Tare weight and Net weights available on the Cylinder.

 The water volume of standard cylinder is about 50Litres.

 Pressure Full gas cylinder about 150Kg/Cm2. We may check the same by using regulators.

3. How to check exact cubic meter of gas present in cylinder at the time of receiving cylinder?

 We know the approx volume and then verify pressure and apply ideal gas law as given above.

4. How to calculate (Conversion factors) exact cubic meter of gas present in cylinder by taking before use and After use weighing of cylinder (Unit: Kgs.)

 After some gas usage from the full cylinder chech the pressure remained in the cylinder.

 Assume the gas remained is 90Kg/Cm2. As per Ideal gas law the volume of gas available in the cylinder is 4500 Litres.

 If you want to know the weight of the gas multiply the volume with density (N2 gas density is 0.967g/cm3).

 Weight=Volume x Gas density =4500x0.967 = 4351.5gms = 4.35Kg.