Study on the dipole moment of asphaltene molecules through dielectric measuring

Handle URI:
http://hdl.handle.net/10754/600235
Title:
Study on the dipole moment of asphaltene molecules through dielectric measuring
Authors:
Zhang, Long Li; Yang, Chao He; Wang, Ji Qian; Yang, Guo Hua; Li, Li; Li, Yan Vivian; Cathles, Lawrence
Abstract:
The polarity of asphaltenes influences production, transportation, and refining of heavy oils. However, the dipole moment of asphaltene molecules is difficult to measure due to their complex composition and electromagnetic opaqueness. In this work, we present a convenient and efficient way to determine the dipole moment of asphaltene in solution by dielectric measurements alone without measurement of the refractive index. The dipole moment of n-heptane asphaltenes of Middle East atmospheric residue (MEAR) and Ta-He atmospheric residue (THAR) are measured within the temperature range of -60°C to 20°C. There is one dielectric loss peak in the measured solutions of the two types of asphaltene at the temperatures of -60°C or -40°C, indicating there is one type of dipole in the solution. Furthermore, there are two dielectric loss peaks in the measured solutions of the two kinds of asphaltene when the temperature rises above -5°C, indicating there are two types of dipoles corresponding to the two peaks. This phenomenon indicates that as the temperature increases above -5°C, the asphaltene molecules aggregate and present larger dipole moment values. The dipole moments of MEAR C7-asphaltene aggregates are up to 5 times larger than those before aggregation. On the other hand, the dipole moments of the THAR C7-asphaltene aggregates are only 3 times larger than those before aggregation. It will be demonstrated that this method is capable of simultaneously measuring multi dipoles in one solution, instead of obtaining only the mean dipole moment. In addition, this method can be used with a wide range of concentrations and temperatures.
Citation:
Zhang L, Yang C, Wang J-Q, Yang G, Li L, et al. (2015) Study on the dipole moment of asphaltene molecules through dielectric measuring. Fuel 140: 609–615. Available: http://dx.doi.org/10.1016/j.fuel.2014.10.010.
Publisher:
Elsevier BV
Journal:
Fuel
KAUST Grant Number:
KUS-C1-018-02
Issue Date:
Jan-2015
DOI:
10.1016/j.fuel.2014.10.010
Type:
Article
ISSN:
0016-2361
Sponsors:
This publication was made possible by facilities created under Award No. KUS-C1-018-02 made by King Abdullah University of Science and Technology (KAUST). This work was partial supported by the National Science Fund Committee of China (20776160), and the Fundamental Research Funds for the Central Universities (14CX05029A). Thanks for Professor Kongshuang Zhao in Laboratory for Dielectric Relaxation Spectroscopy Analysis in Beijing Normal University for the valuable discussion.
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Full metadata record

DC FieldValue Language
dc.contributor.authorZhang, Long Lien
dc.contributor.authorYang, Chao Heen
dc.contributor.authorWang, Ji Qianen
dc.contributor.authorYang, Guo Huaen
dc.contributor.authorLi, Lien
dc.contributor.authorLi, Yan Vivianen
dc.contributor.authorCathles, Lawrenceen
dc.date.accessioned2016-02-28T07:59:40Zen
dc.date.available2016-02-28T07:59:40Zen
dc.date.issued2015-01en
dc.identifier.citationZhang L, Yang C, Wang J-Q, Yang G, Li L, et al. (2015) Study on the dipole moment of asphaltene molecules through dielectric measuring. Fuel 140: 609–615. Available: http://dx.doi.org/10.1016/j.fuel.2014.10.010.en
dc.identifier.issn0016-2361en
dc.identifier.doi10.1016/j.fuel.2014.10.010en
dc.identifier.urihttp://hdl.handle.net/10754/600235en
dc.description.abstractThe polarity of asphaltenes influences production, transportation, and refining of heavy oils. However, the dipole moment of asphaltene molecules is difficult to measure due to their complex composition and electromagnetic opaqueness. In this work, we present a convenient and efficient way to determine the dipole moment of asphaltene in solution by dielectric measurements alone without measurement of the refractive index. The dipole moment of n-heptane asphaltenes of Middle East atmospheric residue (MEAR) and Ta-He atmospheric residue (THAR) are measured within the temperature range of -60°C to 20°C. There is one dielectric loss peak in the measured solutions of the two types of asphaltene at the temperatures of -60°C or -40°C, indicating there is one type of dipole in the solution. Furthermore, there are two dielectric loss peaks in the measured solutions of the two kinds of asphaltene when the temperature rises above -5°C, indicating there are two types of dipoles corresponding to the two peaks. This phenomenon indicates that as the temperature increases above -5°C, the asphaltene molecules aggregate and present larger dipole moment values. The dipole moments of MEAR C7-asphaltene aggregates are up to 5 times larger than those before aggregation. On the other hand, the dipole moments of the THAR C7-asphaltene aggregates are only 3 times larger than those before aggregation. It will be demonstrated that this method is capable of simultaneously measuring multi dipoles in one solution, instead of obtaining only the mean dipole moment. In addition, this method can be used with a wide range of concentrations and temperatures.en
dc.description.sponsorshipThis publication was made possible by facilities created under Award No. KUS-C1-018-02 made by King Abdullah University of Science and Technology (KAUST). This work was partial supported by the National Science Fund Committee of China (20776160), and the Fundamental Research Funds for the Central Universities (14CX05029A). Thanks for Professor Kongshuang Zhao in Laboratory for Dielectric Relaxation Spectroscopy Analysis in Beijing Normal University for the valuable discussion.en
dc.publisherElsevier BVen
dc.subjectAsphalteneen
dc.subjectDielectric lossen
dc.subjectDipole momenten
dc.subjectPolarityen
dc.titleStudy on the dipole moment of asphaltene molecules through dielectric measuringen
dc.typeArticleen
dc.identifier.journalFuelen
dc.contributor.institutionState Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China)Qingdao, Shandong Province, Chinaen
dc.contributor.institutionCollege of Science, China University of Petroleum (East China)Qingdao, Shandong Province, Chinaen
dc.contributor.institutionDepartment of Design and Merchandising, Colorado State University, 326 Gifford, 1574 Campus DeliveryFort Collins, CO, United Statesen
kaust.authorZhang, Long-lien
kaust.authorLi, Lien
kaust.authorCathles, Lawrenceen
kaust.grant.numberKUS-C1-018-02en
kaust.grant.fundedcenterKAUST-Cornell Center for Energy and Sustainabilityen
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