Using a Thermodynamic Approach to Estimate a Temperature Drop of Natural Gas in a Pressure Regulator

A mathematical model for reducing the pressure of natural gas in a direct acting pressure regulator is developed. It is shown that, if an outlet-inlet pressure ratio typical for practice is lower than a critical value, the pressure reduction process comes down to two stages: partial expansion of gas with throttling in the orifice plate of the pressure regulator and subsequent expansion in its body. The values of the gas temperature in the characteristic sections of the pressure regulator are determined. It is established that the temperature drops at the first stage of pressure reduction and rises as the flow in the pressure regulator body expands and decelerates. A method for minimizing the possibility of formation of gas hydrates in the pressure regulator is proposed.