Effects of Specific Gravity of Natural Gas on Pressure-Volume-Temperature (PVT) behavior According to NX-19 Method

Describing the amount of natural gas consumed by an entire country or a single residential appliance can be confusing, since natural gas can be measured in several different ways. Quantities of natural gas are usually measured in cubic feet or cubic meters. Due to the fact that the pressure, temperature and components of natural gas flow are always differences in several conditions, in custody transfer or fiscal metering it is necessary that the amount of gas flow is calculated in flow conditions and then corrected in standard conditions. So, The correction factor is used to correct the flow amount.The measurement standards are one of the most accessible methods for calculating the correction factor, and the NX-19 method is one of the simplest and easiest methods, because it has the lower dependence on measurement parameters, such as the components of natural gas compounds. Therefore, this method has been considered in measurements of gas consumption by major customers at the National Iranian Gas Company. In this research, at first, we will try to describe calculating the correction factor, according to NX-19 method and then we will analyze the effect of specific gravity on the amount of supercompressibility, compressibility and correction factors.