LPG composition
Thread Content
We monitor the quality of liquefied gas by taking samples at a pressure gauge located before the quick connection for loading. The pressure gauge is temporarily removed for sampling; its valve is opened to release pressure until white mist-like gas appears. Samples are then taken in accordance with the specified procedures, and after analysis, the composition of the liquefied gas is as follows: C2 – 27.3834； C3－－60.2998 ； iC4－－5.2184 ； nC4——5.8478 ； iC5－－0.8590 ； nC5――0.3915. But this is very different from the components of liquefied gas as we usually know it. Why? Please share your valuable insights. Note: Samples are taken from the liquid-phase tube. This post was last edited by charlsechen on 2008-7-3 08:24]
One of the reasons is that the sampling point for the pressure gauge is likely connected to the top of the tank. Moreover, the sample you obtained is definitely in the gas phase rather than the liquid phase; try taking samples from the sampling point on the liquid-phase line. Based on your analysis data, it’s clear that it’s the gas composition at the top of the tank
Agree with the person above; the sample you took from the pressure gauge must be in the gas phase. Although you waited until mist appeared before taking the sample, that is still the gas-phase composition. Although the liquid-phase distribution is related to the gas-phase distribution, since the Henry constants of each component differ, their partial pressures in the gas phase are different, and the components themselves also differ.
Such data does not meet the quality standards for liquefied gas; it should be quality data related to the gaseous state. I think the reasons might be, first, the quality of the liquefied gas itself is substandard, with a high content of light components; second, the amount of liquefied gas in the tank truck is very small, and this situation can also occur even when sampling from the liquid-phase pipe.
Agree with what was said on the 2nd floor; the sampling port of the pressure gauge is one of the reasons, and the sample is definitely in gaseous form rather than liquid form