Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Study on the Melting Characteristics of Waxy Crude Oil in Sunken Oil Tank
Yongyan Chen, Wenfeng Wu, Shuai Yang, Xuxiu Wang
School of Naval Architecture and Maritime, Zhejiang Ocean University
Zhoushan, Zhejiang, China

precipitated. The precipitation of wax will affect the porosity andpermeability of wax crystal porous media, and affect the heat transferof heating and melting; the non-Newtonian characteristics of waxy
crude oil will affect the apparent viscosity, and then affect the heattransfer characteristics of waxy crude oil. According to the literature,most scholars do not consider the waxiness and non-Newtonian
characteristics of crude oil when studying the heating of crude oil.
There are few studies on the heating and melting of waxy crude oil,mainly through physical experiment methods and numerical simulation
methods. Research.my country is a big country of crude oil, and thetransportation of crude oil is inseparable from ships. Affected byvarious factors, shipwreck accidents occur from time to time. In order
to avoid oil leakage and pollute the seawater environment and reduce
the salvage weight, it is necessary to carry out wreck salvage. However,
due to the low seawater temperature, the viscosity of the oil increases,
making it difficult to pump it ashore, which requires heating the oil
before salvaging. However, the crude oil imported and exported athome and abroad has a relatively high wax content. If the ambient
temperature drops to the wax precipitation temperature of the waxy
crude oil, wax will be precipitated. The precipitation of wax will affectthe porosity and permeability of wax crystal porous media, and affectthe heat transfer of heating and melting; the non-Newtonian
characteristics of waxy crude oil will affect the apparent viscosity, andthen affect the heat transfer characteristics of waxy crude oil.
According to the literature, most scholars do not consider the waxinessand non-Newtonian characteristics of crude oil when studying theheating of crude oil. There are few studies on the heating and meltingof waxy crude oil, mainly through physical experiment methods andnumerical simulation methods.

ABSTRACT
Based on the enthalpy-porous medium theory, a mathematical model ofthe melting phase transition process of waxy crude oil in shipwreck oiltanks is established. The research results show that in the early stage ofmelting, the heating rate decreases with the increase of wax content,
and the greater the wax content, the greater the temperature
inhomogeneity; in the later stage of heating, the heating rate increases
with the increase of wax content, and the larger the amount of wax, thesmaller the temperature non-uniformity. Permeability constants of wax
crystalline porous media affect non-Newtonian behavior on meltingprocesses. When the permeability constant is small, the non-Newtonian
characteristics have little effect on the melting process; on the contrary,when the permeability constant is large, the non-Newtonian
characteristics have a certain influence on the melting process.
Permeability constants of wax crystalline porous media affect nonNewtonian behavior on melting processes. When the permeability
constant is small, the non-Newtonian characteristics have little effecton the melting process; on the contrary, when the permeability constantis large, the non-Newtonian characteristics have a certain influence onthe melting process.

KEY WORDS: Enthalpy-Porous Media Theory; Waxy Crude Oil;
Non-Newtonian Properties.

INTRODUCTION
China is a big country of crude oil, and the transportation of crude oil is
inseparable from ships. Affected by various factors, shipwreck
accidents occur from time to time. In order to avoid oil leakage andpollute the seawater environment and reduce the salvage weight, it isnecessary to carry out wreck salvage. However, due to the low seawatertemperature, the viscosity of the oil increases, making it difficult topump it ashore, which requires heating the oil before salvaging.
However, the crude oil imported and exported at home and abroad hasa relatively high wax content. If the ambient temperature drops to thewax precipitation temperature of the waxy crude oil, wax will be

Cheng et al. (2000) conducted comparative experiments on crude oil
after different heat treatments, and analyzed the mechanism of thermal
history effect on the rheological properties of waxy crude oil. Feng et al.
(2007) took the representative Panyu crude oil as an example, andconducted a rheological performance test on waxy crude oil through aseries of heat treatment and shear treatment tests. The rheologicalcharacteristics, rheological types and total viscosity-temperature curveof waxy crude oil and thixotropy of waxy crude oil by means of894