Propane Tank Leakage

[mstew]

I have a 1000 gallon propane tank. I live in Virginia. There is a very small leak in the service valve. On January 3rd, the tank contained approximately 550 gallons of propane. I checked the tank on September 1st, and there was no gas in the tank. I would like to determine if I could lose all of this quantity in 8 months through this very small opening. The rule of thumb for tank pressure is 2 times the ambient air temperature. The average temperature during this time period was probably 65 degrees. I was told that 1 gallon of liquid propane is equivalent to 270 gallons of propane gas. I don't know the size of the opening, but the propane company rates it as a class 1/8 leak. The system beyond the tank is not closed. There is apparently another leak downstream. Can anyone help me determine how long it would take to disipate the contents of the tank through this small opening and provide me the calculations used to make this determination.

[admin]

Very important is the pressure.

The rule of thumb for tank pressure is 2 times the ambient air temperature

How do you know this. At 65 F I think pressure of liquid propane is much higher - have to check it.

Here is discharge formula for gas.

As pressure is dropping in time I suggest you to use average pressure level, between pressure on the start and zero, which is actually half of pressure on the start.

[mstew]

I guess that the formula I want to use is w=(1.111)(10 to the -6th power)(y)(d to the second power). I want to solve for d. One gallon of propane expands by a factor of 277 times when changed to a gaseous state. How do I use this information to define w. What should I use for the pressure drop, density, and resistance coefficient. I am not an engineer or physicist. I have no idea how to complete this equation. Can you help or refer me to a service that can help me?

[admin]

Pressure drop is difference between pressure in tank and atmospheric pressure. Density is one inside the tank at internal pressure. Resistance coefficient is difficult one - as you should know more information about the geometry shape and obstacles that fluid is going through from tank to atmosphere.

Please confirm pressure that was in tank as it is starting point for any attempt to find as close solution as possible for your problem.