Effect of Pressure on methane Absorption Characteristic in IR Region

摘要

Methane absorption properties under the pressure from 0.01 MPa to 4 MPa are studied with infrared spectrometer at normal temperature. Gas concentration of methane remains unchanged and nitrogen is gradually added to increase the pressure. Test results show that the absorbance changes a little, almost like a straight line at the beginning. When the pressure continues to increase, absorbance significantly decreases. While the pressure increases to a definite value, absorbance enters into another stable region. No frequency shift appears in absorption line shape but the pressure broadening effect can be observed. So, when high pressure methane in pipeline is measured by absorption spectroscopy, the effect of absorption properties brought about by pressure must be considered, and pressure correction is then needed.