Determination of the water content in petroleum products using terahertz transmission spectroscopy

The water content in polyglycol oils is investigated by Terahertz Time-Domain Spectroscopy (THz-TDS). These oils are able to dissolve a certain percentage of water. Changes in the absorption coefficient and refractive index are observed related to the amount of water added to the pure oils. Comparison of the experimental data with predictions based on Beer-Lambert and Lorentz-Lorenz-theory, respectively, exhibits an excellent agreement. Analyses with Fourier Transform Infrared (FTIR) Spectroscopy reveal sensitivity similar to the THz-TDS experiment. THz-TDS may offer powerful tools to quantitatively determine the water concentration in petroleum products.

[1]  X. C. Zhang,et al.  Electrooptic sampling of freely propagating terahertz fields , 1996 .

[2]  R. Alfano,et al.  Reorientation of the H2O cage studied by terahertz time-domain spectroscopy , 2005 .

[3]  R. E. Miles,et al.  Terahertz Transmission Spectroscopy of Nonpolar Materials and Relationship with Composition and Properties , 2004, Infrared and Millimeter Waves, Conference Digest of the 2004 Joint 29th International Conference on 2004 and 12th International Conference on Terahertz Electronics, 2004..

[4]  C. Winnewisser,et al.  Electro-optic detection of THz radiation in LiTaO3, LiNbO3 and ZnTe , 1997 .

[5]  Hanspeter Helm,et al.  Terahertz-Time-Domain-Spektroskopie mit einem leistungsoptimierten elektrooptischen Detektionsverfahren (Low-Power Terahertz Time-Domain Spectroscopy with Optimized Electro-optical Detection) , 2005 .

[6]  So,et al.  INVESTIGATION OF THE TEMPERATURE DEPENDENCE OF DIELECTRIC RELAXATION IN LIQUID WATER BY THZ REFLECTION SPECTROSCOPY AND MOLECULAR DYNAMICS SIMULATION , 1997 .

[7]  Ronei J. Poppi,et al.  Application of mid infrared spectroscopy and iPLS for the quantification of contaminants in lubricating oil , 2005 .

[8]  Charles A. Schmuttenmaer,et al.  Far-infrared absorption spectra of water, ammonia, and chloroform calculated from instantaneous normal mode theory , 1997 .

[9]  A. K. Ramdas,et al.  Broadened Far-Infrared Absorption Spectra for Hydrated and Dehydrated Myoglobin , 2004 .

[10]  Richard Baraniuk,et al.  Material parameter estimation with terahertz time-domain spectroscopy. , 2001, Journal of the Optical Society of America. A, Optics, image science, and vision.

[11]  R. Jacobsen,et al.  Generation and detection of terahertz pulses from biased semiconductor antennas , 1996 .