What is JT Effect?

JT Effect, also referred to as the Joule-Thomson effect, is an important concept for oil and gas producers to be aware of. Discovered by British physicists in the 19th century, this principle states that when the pressure of a gas changes, its temperature also changes.

Freezing Gas Lines

When gas pressure is reduced across a control valve or pressure reducing regulator, its temperature is also reduced. Because all gas carries some element of moisture in it, this can present a potential freezing issue when the temperature of your gas line drops below 32 degrees Fahrenheit.

To identify the potential for freezing in your gas line, calculate the temperature drop and subtract from the initial temperature. The formula for this is:

100 PSI pressure drop = approx. 7 degree (F) temperature drop

For example, say you are cutting the gas pressure from 400 to 200 across a pressure reducing regulator. The temperature of the gas would drop 14 degrees when flowing across the regulator.

Solution for Freezing

To prevent freezing, operators sometimes wrap insulation and heat tape around their valve. This method presents a challenge when you need to check or repair the valve.

Kimray recommends using a CATCO Catalytic Heater. This heater uses supply gas to provide a flameless heat that keeps your valve and pipeline above freezing. The CATCO heater features a side door that allows operators easy access for maintenance or repair. The surface of the heater reaches a maximum of 700°F, approved for hazardous environments

For more information about the CATCO heater or any other Kimray product, contact your local Kimray store or authorized distributor.

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