Ammonia Vaporisers

WHY USE A VAPORISER ?

Ammonia is shipped and stored under pressure in liquid form in cylinders or tanks, but it is most often used as gaseous ammonia.  A specific amount of heat called "latent heat of vaporisation" is necessary to convert each kilogram of liquid ammonia into a gas.  

Approximately 1371 kj/kg per pound is the required heat necessary to provide the latent heat of vaporisation to maintain a specific gas flow from the storage tank.  If this heat is not available from the ambient air surrounding the tank, the heat will be taken from the liquid ammonia remaining in the tank, causing the liquid temperature to drop.

When the liquid temperature drops it causes the vapour pressure to decrease.  If the vapour pressure drops too low, it can reach a point where there is an insufficient amount of pressure to operate the system.  

The situation is further compounded when the temperature of the ambient air surrounding the tank drops and the moisture in the air freezes on the tank surface.  The ice acts as an insulator, further preventing heat from entering the tank.  

A vaporiser is therefore used in situations where the vapour withdrawal rates are so high that ambient heat is not sufficient to sustain the vapour flow.  As a guide, a vaporiser should be utilized when the vapour withdrawal rate of a 1000 gallon tank exceeds 500 SCFH.

James Hogg - Anhydrous Ammonia Vaporizers

Vaporisation takes place when liquid ammonia vaporises and replaces the vapour that is being withdrawn from the top of the tank.  A vaporiser is needed if the heat from the air surrounding the tank is not sufficient or cannot flow through the walls of the tank fast enough to maintain the vaporising rate.  If sufficient ambient heat is not available, the pressure in the tank will drop causing a system shut-down. 

The requirement or need for this supplemental heat is dependent on several factors:  the ambient temperature of air surrounding the tank, the air movement around the tank, the volume of liquid within the tank and the gas withdrawl rate. 

An ammonia vaporiser will take the liquid ammonia from the tank or cylinder and input the required latent heat to generate the required gas flow.

Hogg Ammonia Vaporiser Skids

Vaporizer packages are available with two options for the heat source:

Option 1: Steam ammonia vaporiser

Option 2: Electric heating elements for either 240v single phase or 415 v three   phase supplies.

Vaporiser Electrode Parts Parts Diagram