Some small propane loads can be supplied with vapor drawn directly off the top of a tank. Heat is conducted from outside the tank to the propane liquid at a rate sufficient to support the required vaporization. In the process, a gallon of liquid propane will become approx. 36 cubic feet of vapor. For industrial and larger commercial loads, this simple approach to vaporization has limited application. Instead, "vaporizers" are used to heat the liquid propane, creating the needed volume of vaporized gas.

Vaporizers are available in sizes from ten gallons to thousands of gallons per hour. Several basic configurations are shown in the diagrams below. Note that required controls and safety devices are not shown in detail.

Direct Fired

Direct-Fired Vaporizer

Direct-Fired Waterbath Vaporizer

Indirect-Fired

Indirect-Fired Waterbath Vaporizer

Electric Vaporizer

A gallon of liquid propane will produce about 36 standard cubic feet (scf) of vapor.

Each scf of propane vapor contains about 2,520 btu of available energy when burned.

Indirect-Fired Waterbath Vaporizer ("Dual Loop" / Steam)

Proper design of piping, pressure control and overpressure protection can ensure safe and reliable vaporizer operation. For example, the operating pressure downstream of a vaporizer must be low enough to avoid condensation of vaporized propane under the coldest ambient conditions. (See Figure 1 in Appendix for propane dew points.)

Steam Vaporizer