How to Heat Liquids in Vessels

There are many advantages to using eductors for heating liquids in open vessels. These give the vessel heating eductor a place as a viable option for heating in many types of vessels.

The eductor heater provides direct contact of the steam into the liquid. This assures complete transfer of the energy in the steam into the liquid being heated. Other types of heating lose efficiency as the interior of the heat exchanger builds up a scale. With eductors, the velocity of the steam being injected into the vessel also causes the liquid con­tents of the vessel to be agitated while heat­ing occurs, without the need for other types of mixers in the vessel. This provides for more even heating of the vessel contents. They also permit the steam to be dispersed over more of the liquid volume, resulting in a more homogenous heating than with other methods of injecting steam.

These designs of eductors allow steam to be used from 10 to 140 PSIG for heating. Because of the nature of direct steam injection, heating vessels at atmospheric pressure beyond 140°F should not be attempted. Exceeding this temperature could result in uncondensed steam evolving from the liquid.

The standard Jerguson/Jacoby-Tarbox models for heating in vessels are the TLA and ULJ. The model TLA is well suited to providing strong tank agitation while heat­ing. Compared with other heaters, the cost per application is small. The model ULJ is designed to provide vigorous circulation of the liquid with low pressure steam inputs.

TLAs should be located with the outlet pointed toward the most remote portion of the tank to provide the best agitation possible.

• The liquid in the vessel is Water (Sg =1.0)
• The temperature rise desired is ∆T = 50°F
• The final tank temperature is 120°F
• The vessel holds 550 Gal
• The time to heat it is 20 Min
• Steam is available at 40 PSIG
• Use two eductors