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Propane Operations

Propane Container Purging Procedures

The purging procedure to be used on all new tanks from manufacturer or NH³ tanks that have been cleaned and checked for NH³ vapor, is as follows:

1. Remove dehydrated air pressure from the container by blowing to the atmosphere.
2. Using vapor line from bobtail, fill container to approximately 20 to 30 Lbs. Pressure on the gauge. Never purge with liquid—the Liquid will condense the water vapor in the tank and remain in tank during blow down.
3. Shut off vapor hose valve and use Rego #3119A withdrawal adapter, blow to atmosphere, down to approximately 1 Lb. pressure.
4. Repeat step 2.
5. Repeat step 3.
6. Repeat step 2 and 3 as required. See chart on purging tanks below.
7. Using alcohol injector, install one pint Menthol Alcohol for the 120-gallon container, install one quart Menthol Alcohol foe the 250-gallon container, install one-half gallon Menthol Alcohol for the 500-gallon container, and one gallon Menthol Alcohol for the 1,000-gallon container.
8. Using liquid line form bobtail, fill container to approximately 5%.

It is recommended that the purging procedure as outlined above be done at the bulk plant or warehouse before being delivered to patron location.

Experience indicates that a reduction of the residual air content to 6.25% is adequate. The resulting mixture will have a thermal value of about 2400 BTU. In this case, the serviceman can adjust the burners for a slightly richer product. Moreover, the slight volume of air will to some extent dissolve in the propane if the installation stands unused for a few days.

How much product was consumed?  If instructions above were carefully followed and the vapor was purged five times, a total of 670 cu. ft. (15.4 gallon.) would have been used for a 1,000-gallon tank. In a 500-gallon tank, a total of 7.7 gallons would have been used.

There is no other practical way to extract the air from the tank so quickly or so economically.

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