THERMAL SCIENCE

International Scientific Journal

Ying Xu

,

Yuqi Zhang

,

Xin Nie

,

Xiaoyan Liu

,

Lijun Liu

STUDY ON MICROSTRUCTURE WAX EVOLUTION BEHAVIOR OF WAXY CRUDE OIL DURING COOLING

ABSTRACT
The microcosmic characteristics of wax evolution of waxy crude-oil directly affect the heat transfer process of crude-oil. A microscopic experiment was carried out on the wax deposit process of waxy crude-oil by polarized light microscopy. The phase change characteristics of wax crystals during wax deposit process were analyzed, and the process of wax crystal precipitation was quantitatively analyzed by the image analysis software ImageProPlus. The results show that the wax deposit process mainly includes wax crystal nucleation, growth and bonding, which together lead to the formation of wax crystal network. The sample oil particle number and the wax crystal area fraction curves have inflection points at 41 ℃ and 38℃, respectively, which are caused by different carbon number alkane content and wax crystal bonding. By analyzing the particle size and particle area curves, it is known that nucleation precipitation and growth are alternately dominant in the early stage of wax crystal growth. Through the wax roundness study, it is found that the growth of wax crystals in the early stage is mainly in the longitudinal direction, and the growth in the late stage is not directional. According to the phase change process of wax crystal, it is proposed that the temperature of the crude-oil with porous media grid structure is coalescence point. By using the position point tracking of wax crystal and analysis of the variation characteristics of microscopic parameters, the coalescence point temperature of the sample crude-oil in this experiment is 38℃.
KEYWORDS
wax crystal, microscopic properties, polarized light microscopy, quantitative analysis, heat transfer process
PAPER SUBMITTED: 2021-12-06
PAPER REVISED: 2022-03-10
PAPER ACCEPTED: 2022-03-14
PUBLISHED ONLINE: 2022-04-09
DOI REFERENCE: https://doi.org/10.2298/TSCI211206048X
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2022, VOLUME 26, ISSUE Issue 6, PAGES [4633 - 4643]
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Study on microstructure wax evolution behavior of waxy crude oil during cooling

© 2024 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence