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Anhydrous Ammonia Tank Conversions

Cleaning NH³ Nurse Tanks to supply Propane for Grain Drying

Three methods of cleaning NH³ tanks for storage of Propane have been approved:

1. Steam
2. Water
3. Air

1. Remove all liquid and vapor from tank, bring container to atmospheric pressure, using any one of the three methods listed above.
2. Use a steam source with 20 to 50 psi pressure.

1. Connect steam line to vapor connection tank.
2. Open liquid out valve.
3. Start steam into container and slowly close liquid out valve until pressure builds to approximately 15 lbs.—leave valve so that 15 lbs. Is maintained in container.
4. Continue steaming until steam from liquid out valve test ammonia free (see testing procedure, listed below)
5. Purge with Propane vapor. Refer to Chapter 4, Purging Procedure.

3. Use only soft water. Hard water may result in calcium carbonate deposits.

1. Open all top valves.
2. Remove relief valves if necessary.
3. Flood container to over flowing.
4. Remove bottom plug or open bottom valve.
5. Test for ammonia (see testing procedure, listed below)
6. Purge with Propane vapor. Refer to Chapter 4, Purging Procedure.

4. Use air from compressor, vacuum cleaner

1. Connect air connection to liquid connection on container.
2. Build air pressure to approximately 15 lbs. If using compressor.
3. Continue to move air through container until ammonia free. (see testing procedures, listed below)
4. Purge with Propane vapor. Refer to Chapter 4, Purging Procedure.

5. Testing for NH³

1. moisten a piece of red litmus paper with distilled water and hold in air, or steam coming from container opening, for 10 seconds
2. If litmus paper turns blue, ammonia is still present. Continue cleaning. Retest until red litmus paper remains red.

6. Adding Methanol Alcohol

1. When using steam or water cleaning methods, add Methanol Alcohol. After container has been drained and cooled, install 2 gallon of alcohol per 1000 gallon and drain in 1-2 hours.
2. Add 1 gallon of alcohol to 1000 gallon capacity and use purging procedure for Propane.
3. Using air method add 1 gallon of alcohol and us purging procedure for Propane.

7. Purge container with Propane vapor. See Chapter 4, Purging Procedure.
8. Relief valve must be reinstated from ¾" to the 1 ¼".
9. Nurse tanks and all Propane tanks cannot be moved over the road with more than 5% liquid Propane in them.
10. The above procedures are to be used in transporting and storing Propane in NH³ containers. These duel-use containers may not be attached to houses to supply propane for heating purposes—only for grain drying. When Propane and NH³ are combined, they produce a lethal gas as well as corrode and harm the internal Propane system.

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Revised March, 1999