Molecular dynamics simulation of wax molecules aggregational crystallization behavior during cooling of crude oil mixture
The crystallization behavior of wax molecules is the root cause of wax deposition. In this study, molecular dynamics simulations were used to investigate the aggregational crystallization behavior of wax molecules in a crude oil system. The results show that wax molecules produce ordered wax crystal...
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| Format: | Article |
| Idioma: | anglès |
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Elsevier
2022-09-01
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| Col·lecció: | Case Studies in Thermal Engineering |
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| Accés en línia: | https://doi.org/10.1016/j.csite.2022.102298 http://www.sciencedirect.com/science/article/pii/S2214157X2200541X |
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| _version_ | 1878755200219480064 |
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| author | Hengguang Cao Xuewen Cao Xiangyang Zhao Dan Guo Yang Liu Jiang Bian |
| author_browse | Dan Guo Hengguang Cao Jiang Bian Xiangyang Zhao Xuewen Cao Yang Liu |
| author_facet | Hengguang Cao Xuewen Cao Xiangyang Zhao Dan Guo Yang Liu Jiang Bian |
| author_sort | Hengguang Cao |
| collection | DOAJ |
| description | The crystallization behavior of wax molecules is the root cause of wax deposition. In this study, molecular dynamics simulations were used to investigate the aggregational crystallization behavior of wax molecules in a crude oil system. The results show that wax molecules produce ordered wax crystal structures from the disordered liquid phase crude oil system under van der Waals forces at low temperatures. The crystallization of wax molecules consists of three main processes: carbon chain extension, nucleation of wax molecules and wax crystal growth. The lower the temperature of the crude oil system and the lower the cooling rate, the higher the degree of aggregation of wax molecules, the smaller the number of wax crystals and the larger the crystal size. In addition, asphaltene molecules are found to aggregate by face-to-face stacking and T-shaped stacking at low temperatures. Based on the spatial steric hindrance effect, the asphaltene aggregates prevent further aggregation between wax crystal clusters. Asphaltenes lead to an increase in the liquid content of the wax deposit layer, causing the yield stress of the deposit to decrease and the structural strength to weaken. |
| doi_str_mv | 10.1016/j.csite.2022.102298 |
| format | Article |
| id | doaj-4e903904aaa14030bdfd2230b414606c |
| institution | Biblioteca Central PEMEX |
| issn | 2214-157X |
| language | English |
| publishDate | 2022-09-01 |
| publishDateRange | 2022-09-01 |
| publishDateSort | 2022-09-01 |
| publisher | Elsevier |
| publisherStr | Elsevier |
| record_format | Article |
| series | Case Studies in Thermal Engineering |
| spelling | doaj-4e903904aaa14030bdfd2230b414606cengElsevierCase Studies in Thermal Engineering2214-157X2022-09-013710229810.1016/j.csite.2022.102298Molecular dynamics simulation of wax molecules aggregational crystallization behavior during cooling of crude oil mixtureHengguang Cao0Xuewen Cao1Xiangyang Zhao2Dan Guo3Yang Liu4Jiang Bian5College of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao, 266580, ChinaCorresponding author.; College of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao, 266580, ChinaCollege of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao, 266580, ChinaCollege of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao, 266580, ChinaCollege of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao, 266580, ChinaCorresponding author.; College of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao, 266580, ChinaThe crystallization behavior of wax molecules is the root cause of wax deposition. In this study, molecular dynamics simulations were used to investigate the aggregational crystallization behavior of wax molecules in a crude oil system. The results show that wax molecules produce ordered wax crystal structures from the disordered liquid phase crude oil system under van der Waals forces at low temperatures. The crystallization of wax molecules consists of three main processes: carbon chain extension, nucleation of wax molecules and wax crystal growth. The lower the temperature of the crude oil system and the lower the cooling rate, the higher the degree of aggregation of wax molecules, the smaller the number of wax crystals and the larger the crystal size. In addition, asphaltene molecules are found to aggregate by face-to-face stacking and T-shaped stacking at low temperatures. Based on the spatial steric hindrance effect, the asphaltene aggregates prevent further aggregation between wax crystal clusters. Asphaltenes lead to an increase in the liquid content of the wax deposit layer, causing the yield stress of the deposit to decrease and the structural strength to weaken.http://www.sciencedirect.com/science/article/pii/S2214157X2200541XWaxy crude oilMolecular dynamics simulationWax crystalAggregationAsphaltene |
| spellingShingle | Hengguang Cao Xuewen Cao Xiangyang Zhao Dan Guo Yang Liu Jiang Bian Molecular dynamics simulation of wax molecules aggregational crystallization behavior during cooling of crude oil mixture Case Studies in Thermal Engineering Waxy crude oil Molecular dynamics simulation Wax crystal Aggregation Asphaltene |
| title | Molecular dynamics simulation of wax molecules aggregational crystallization behavior during cooling of crude oil mixture |
| title_full | Molecular dynamics simulation of wax molecules aggregational crystallization behavior during cooling of crude oil mixture |
| title_fullStr | Molecular dynamics simulation of wax molecules aggregational crystallization behavior during cooling of crude oil mixture |
| title_full_unstemmed | Molecular dynamics simulation of wax molecules aggregational crystallization behavior during cooling of crude oil mixture |
| title_short | Molecular dynamics simulation of wax molecules aggregational crystallization behavior during cooling of crude oil mixture |
| title_sort | molecular dynamics simulation of wax molecules aggregational crystallization behavior during cooling of crude oil mixture |
| topic | Waxy crude oil Molecular dynamics simulation Wax crystal Aggregation Asphaltene |
| url | https://doi.org/10.1016/j.csite.2022.102298 http://www.sciencedirect.com/science/article/pii/S2214157X2200541X |
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