Crude Oil Asphaltenes Studied by Terahertz Spectroscopy

Terahertz time-domain spectroscopy (THz-TDS) was used to study the asphaltenes in different crude oils. THz-TDS has a feature of measuring the amplitude and time delay and consequently the refractive index and absorption coefficient spectra simultaneously. Our approach was based on measuring the THz signal from neat crude oil samples and comparing it with the THz signal after removing the asphaltene from the oil samples (maltene). The results show that the differences in the time delay and the peak amplitude between the neat oil and the maltene have a linear relation with the asphaltene content. The refractive index spectra of the asphaltene show variation in the low THz frequencies and comparable spectra in the higher frequencies. The absorption of the asphaltene was mild, and no distinctive absorption feature was observed except for some narrow absorption peaks that we attributed to water molecules adsorbed on the asphaltene.

[1]  Jeramie J. Adams.  Asphaltene Adsorption, a Literature Review , 2014 .

[2]  M. Koch,et al.  Terahertz spectroscopy and imaging – Modern techniques and applications , 2011 .

[3]  K. Chau,et al.  Measuring Asphaltene Deposition Onset from Crude Oils Using Surface Plasmon Resonance , 2017 .

[4]  J. Castillo,et al.  Measurement of the Refractive Index of Crude Oil and Asphaltene Solutions: Onset Flocculation Determination , 2010 .

[5]  R. Tao and,et al.  Reducing the Viscosity of Crude Oil by Pulsed Electric or Magnetic Field , 2006 .

[6]  Brent M. Polishak,et al.  Broadband terahertz characterization of the refractive index and absorption of some important polymeric and organic electro-optic materials , 2011 .

[7]  J. B. Baxter,et al.  Terahertz spectroscopy. , 2011, Analytical chemistry.

[8]  Kun Zhao,et al.  The spectral analysis of fuel oils using terahertz radiation and chemometric methods , 2016 .

[9]  Okan Esenturk,et al.  Applications of terahertz spectroscopy in biosystems. , 2007, Chemphyschem : a European journal of chemical physics and physical chemistry.

[10]  Kun Zhao,et al.  Qualitative identification of crude oils from different oil fields using terahertz time-domain spectroscopy , 2015 .

[11]  Qingli Zhou,et al.  Optical property and spectroscopy studies on the selected lubricating oil in the terahertz range , 2009 .

[12]  A. Guzmán,et al.  Mid-infrared Attenuated Total Reflectance (MIR-ATR) Predictive Models for Asphaltene Contents in Vacuum Residua: Asphaltene Structure–Functionality Correlations Based on Partial Least-Squares Regression (PLS-R) , 2011 .

[13]  Enrique Mejía-Ospino,et al.  Prediction of the SARA analysis of Colombian crude oils using ATR-FTIR spectroscopy and chemometric methods , 2012 .

[14]  Honglei Zhan,et al.  Spectral characterization of the key parameters and elements in coal using terahertz spectroscopy , 2015 .

[15]  Kun Zhao,et al.  Experimental measurements of water content in crude oil emulsions by terahertz time-domain spectroscopy , 2013, Applied Geophysics.

[16]  Masahiko Tani,et al.  Investigation of inflammable liquids by terahertz spectroscopy , 2005 .

[17]  J. Castillo,et al.  Determination of Asphaltene and Resin Content in Venezuelan Crude Oils by Using Fluorescence Spectroscopy and Partial Least Squares Regression , 2006 .

[18]  H. S. Fogler,et al.  A Fundamental Study of Asphaltene Deposition , 2013 .

[19]  Dale E. Gary,et al.  Terahertz study of 1,3,5-trinitro-s-triazine by time-domain and Fourier transform infrared spectroscopy , 2004 .

[20]  Kun Zhao,et al.  Simultaneous Characterization of Water Content and Distribution in High-Water-Cut Crude Oil , 2016 .

[21]  F. Mostowfi,et al.  Asphaltene Content Measurement Using an Optical Spectroscopy Technique , 2013 .

[22]  Yunqing Chen,et al.  THz wave sensing for petroleum industrial applications , 2007 .

[23]  Wenxin Li,et al.  Characterization of crystal transformation in the solid-state by terahertz time-domain spectroscopy , 2007 .

[24]  Kun Zhao,et al.  Optical Characterization of the Principal Hydrocarbon Components in Natural Gas Using Terahertz Spectroscopy , 2015 .

[25]  J. Sjöblom,et al.  Determination of saturate, aromatic, resin, and asphaltenic (SARA) components in crude oils by means of infrared and near-infrared spectroscopy , 2001 .

[26]  Berna Hascakir,et al.  The Role of Resins, Asphaltenes, and Water in Water–Oil Emulsion Breaking with Microwave Heating , 2015 .

[27]  O. Mullins,et al.  Asphaltene Densities and Solubility Parameter Distributions: Impact on Asphaltene Gradients , 2016 .

[28]  J. Buckley.  Predicting the Onset of Asphaltene Precipitation from Refractive Index Measurements , 1999 .

[29]  T. Darcie,et al.  Plasmonic Antireflection Coating for Photoconductive Terahertz Generation , 2017 .

[30]  J. Speight.  The Chemistry and Technology of Petroleum , 1980 .

[31]  Kun Zhao,et al.  Probing Disaggregation of Crude Oil in a Magnetic Field with Terahertz Time-Domain Spectroscopy , 2014 .

[32]  N. Vieweg,et al.  Terahertz imaging: applications and perspectives. , 2010, Applied optics.

[33]  Ziqiang Yang,et al.  Gbps terahertz external modulator based on a composite metamaterial with a double-channel heterostructure. , 2015, Nano letters.

[34]  H. S. Fogler,et al.  Study of Asphaltene Precipitation Using Refractive Index Measurement , 2003 .

[35]  A. Firoozabadi,et al.  Measuring Asphaltenes and Resins, and Dipole Moment in Petroleum Fluids , 2002 .

[36]  Joo-Hiuk Son,et al.  Measurement depth enhancement in terahertz imaging of biological tissues. , 2013, Optics express.

[37]  Daniel R. Grischkowsky,et al.  Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Vapors , 2004 .

[38]  S. Andersen,et al.  Molecular mechanics and microcalorimetric investigations of the effects of molecular water on the aggregation of asphaltenes in solutions , 2002 .

[39]  L. Barré,et al.  On the Size Distribution of Self-Associated Asphaltenes , 2013 .

[40]  S. Andersen,et al.  Interactions between Asphaltenes and Water in Solutions in Toluene , 2008 .

[41]  K. Crozier,et al.  Surface enhanced Raman spectroscopy of polycyclic aromatic hydrocarbons and molecular asphaltenes , 2015 .

[42]  Shuting Fan,et al.  The potential of terahertz imaging for cancer diagnosis: A review of investigations to date. , 2012, Quantitative imaging in medicine and surgery.

[43]  P. Taday,et al.  Detection and identification of explosives using terahertz pulsed spectroscopic imaging , 2005 .

[44]  Kun Zhao,et al.  Characterization of Morphology and Structure of Wax Crystals in Waxy Crude Oils by Terahertz Time-Domain Spectroscopy , 2017 .