The Joules-Tompson Effect (J-T) is the cooling effect of the expansion of a real gas.
This cooling occurs where a reduction in flow and pressure is induced at a choke, valve or restriction in the system.
Trianglia can calculate the expected temperature drop for specific pressure/temperature conditions and gas compositions.
The temperature depression is a function of gas composition, initial pressure and temperature upstream of restriction and delta P across restriction.
Curves are available for temperature reduction from the expansion natural gas but these do not take into account high percentages of components such as CO2, H2S etc. which will cause deviation from the basic curve.