Anhydrous ammonia is a compound formed by the combination of two (2) gaseous elements, nitrogen and hydrogen.
Ammonia is one (1) part nitrogen to three (3) parts hydrogen. (NH3)
Ammonia by weight is fourteen (14) parts nitrogen to three (3) parts hydrogen that is approximately 82% nitrogen to 18% hydrogen.
Ammonia appears in nature as a natural substance that results from decomposition.
Ammonia vapor is a colorless gas with a pungent odor.
Ammonia exists as a vapor at atmospheric conditions.
Ammonia vapor is lighter than air and tends to rise when released to atmosphere.
Liquid ammonia released to atmosphere forms a white smoke by freezing the moisture in the air.
Liquid ammonia has a very high coefficient of expansion with temperature.
One (1) gallon of liquid ammonia weighs approximately 5 lbs; however, the weight varies with temperature.
When liquid ammonia reaches a temperature between its melting and critical points, it exerts a vapor pressure that increases with temperature.
A closed container of liquid ammonia is in equilibrium with ammonia vapor and the container pressure bears a definite relationship to the temperature.
Boiling point is at -28° F.
Freezing point is at -107.9° F; a white crystalline mass forms.
Critical temperature is at 270.3° F; ammonia exists as a vapor, regardless of pressure above this temperature.
Density of ammonia liquid is 42.57 pounds per cubic feet @ -28° F; ammonia liquid is lighter than water.
Density of ammonia vapor is .5970 pounds per cubic feet compared to air at atmospheric pressure and @ 32° F.
Volume: One (1) pound of ammonia vapor occupies a volume of 22.78 cubic feet at 32° F and atmospheric pressure. One (1) pound of ammonia vapor occupies a volume of 22.5 cubic feet and yields 45 cubic feet of dissociated gas at a ratio of 25% nitrogen and 75% hydrogen @ 70° F and atmospheric pressure.
Ammonia begins dissociating into nitrogen and hydrogen at approximately 850° F.
Storage & Handling
Ammonia is stored and transported as a liquid under pressure.
The pressure on the tank is the liquid pressure and remains the same whether the tank is 10% or 80% full.
The maximum filling level of an anhydrous ammonia tank is 85%.
Ammonia has a great affinity for water, so special care must be taken to keep the ammonia dry.
Anhydrous ammonia is classified by the DOT as a non-flammable gas.
Ammonia vapor is flammable over a narrow range of 16% to 25% by volume in air and a strong ignition source must be present.
Compatibilities & Incompatibilities
Anhydrous ammonia is compatible with carbon steel and iron.
Anhydrous ammonia is not compatible with copper, brass, bronze, zinc or mercury. Ammonia corrodes copper and brass into a blue-green salt.
Ammonium Hydroxide (Aqua)
"Anhydrous" means without water.
When anhydrous ammonia gas is dissolved in water, the resulting material is ammonium hydroxide or aqua ammonia.