Estimation of Gas Leak Volume to Quantify Gaseous Fluid Flow in Processing Plants

Abstract

Leak detection based on volume changes is common in conventional liquid processing systems, but present challenges in gas systems.  This paper estimates the gas leak volume to quantify gaseous fluid flow in processing plants using prior-calibration-relation techniques. The estimation of volume following this pressure-based model requires that the pressure indicator of the gas leak is normalized against the initial volume before the pressure drop. Normalization makes it possible for equivalent pressure and gas volume data to be presented in percentage or fraction, so they are comparable. (This is similar to the pressure reading or drop on the regulator gauge of a gas cylinder, which is proportional to the equivalent gas cylinder weight or volume difference due to the depressurisation) An example of leak estimation for Gas Plant JK – 52 real-time test case modelling is shown in this work. The change in pressure dP was plotted against the change in volume dV in a prior calibration to derive a relationship between dP and dV. For a Pressure drop of 5 bars, Leak Volume = 2.40 m3 or 84.7 scf of gas. Such estimation of actual gas volume is useful in tying gas leak to environmental impact, HSE and in costing of economic loss.