Investigations on water sensitivity and cross sensitivity at nir-analysis of natural gas

Current developments based on near-IR (NIR)-analysis aim for natural gas quality measurement. The disturbance of NOR gas analysis by humidity and the evaluation of the sensitivity potential of NIR humidity measurement were studied. The composition of dry natural gas could be described to 99.9% by the following three groups: CHx, N2, and CO2. At low pressure stage, the mole fraction was equal to the partial pressure of water, while at higher pressure the water concentration deviated from this simple law and depended on the gas composition.