【作者】 王峰；

【导师】 李传宪；

【作者基本信息】 中国石油大学(华东) ， 石油与天然气工程（专业学位）， 2020， 硕士

【摘要】 为保证输油管道的安全、经济运行,工程上常采用化学防蜡的手段来缓解管道蜡沉积问题。近几年,随着纳米材料应用日益广泛,纳米复合防蜡剂引起了一些研究者的广泛关注。本文以EVA/PAMSQ复合防蜡剂和长庆原油为研究对象,总结了EVA/PAMSQ复合防蜡剂对长庆原油蜡沉积特性的影响规律,并探究了热处理温度和管输条件等因素对EVA/PAMSQ复合防蜡剂防蜡效果和对加剂原油蜡沉积特性的影响规律。EVA/PAMSQ复合防蜡剂是由EVA防蜡剂与PAMSQ纳米颗粒熔融共混制成,经流变实验和蜡沉积实验可知,相比传统EVA型聚合物防蜡剂,EVA/PAMSQ复合防蜡剂对长庆原油不仅具有更好的降凝降粘效果,还具有更高的防蜡效率,其对60℃热处理长庆原油的防蜡效率为77.9%,高于EVA型防蜡剂62.3%的防蜡效率,但EVA/PAMSQ复合防蜡剂也进一步提升了原油蜡沉积层的硬度和蜡含量。此外,EVA/PAMSQ复合防蜡剂对原油蜡晶形貌团聚的作用也进一步加强。将长庆空白原油和加剂原油进行50℃、60℃、70℃和80℃等不同热处理温度的预处理,再对油样进行蜡沉积实验和流变实验,得出以下几点规律:(a)EVA/PAMSQ复合防蜡剂的防蜡效果受原油热处理温度的影响,在50℃热处理条件下,防蜡剂对长庆原油无防蜡效果;当热处理温度高于60℃时,防蜡剂的防蜡效率随着热处理温度的升高而降低。在50℃热处理条件下,防蜡剂不能提升长庆原油蜡沉积层蜡含量;当热处理温度高于60℃时,防蜡剂对长庆原油蜡沉积层蜡含量的提升能力随着热处理温度的升高而升高。(b)热处理温度会影响加剂原油的蜡沉积特性,当热处理温度为50℃时,加剂原油的蜡沉积层较软,表底性状差异较小;当热处理温度升至60℃时,蜡沉积层出现明显表底分层;当热处理温度升高到70℃或80℃时,蜡沉积层收缩变薄为一层硬层,无法区分分层情况。另外,随着热处理温度升高,加剂原油的蜡沉积速率降低,蜡沉积层的平均蜡含量升高。(c)随着热处理温度的升高,加剂原油的粘度和低温胶凝结构强度降低;在50℃热处理条件下时,防蜡剂对长庆原油蜡晶形貌基本无改变作用,当热处理温度高于60℃,防蜡剂明显改善了长庆原油蜡晶形貌。对空白原油和加剂原油进行不同油温、壁温和转速条件下的蜡沉积实验,再对原油进行流变实验,得出以下规律:(a)EVA/PAMSQ复合防蜡剂的防蜡效率随着温度区间的的正向移动、油壁温差的增大、流速的增大而减小;EVA/PAMSQ复合防蜡剂对蜡沉积层蜡含量的提升幅度随着温度区间的正向移动、油壁温差的增大、流速的增大而增大。(b)管输条件同样会影响空白和加剂原油的蜡沉积特性,空白和加剂原油的沉积量随着温度区间的的正向移动而减小,随着油壁温差的增大而先增后减,随着流速的增大而减小;空白和加剂原油的蜡沉积层蜡含量随着温度区间的正向移动、油壁温差的增大、流速的增大而增大。(c)改变管输条件(油温、壁温、流速)会影响空白和加剂原油蜡沉积物的结构特征,在冷流状态下,添加防蜡剂对原油蜡沉积层结构无影响;在热流状态下,添加防蜡剂对原油蜡沉积层结构产生显著影响。更多还原

【Abstract】 In order to ensure the safe and economic operation of oil pipelines,chemical wax prevention is often used to alleviate the problem of pipeline wax deposition.In recent years,with the increasing application of nano-materials,some researchers began to focus on the research of the nano-composite wax inhibitors.This article takes EVA/PAMSQ compound wax inhibitor and Changqing crude oil as research objects,summarizes the influence of EVA/PAMSQ compound wax inhibitor on wax deposition characteristics of Changqing crude oil,and explores factors such as heat treatment temperature and pipeline transportation conditions to EVA/PAMSQ compound wax inhibitor anti-wax effect and the effect of the additive crude oil wax deposition characteristics.EVA/PAMSQ compound wax inhibitor is made by melt blending of EVA wax inhibitor and PAMSQ nanoparticles.Through rheological experiments and wax deposition experiments,it is known that compared with traditional EVA polymer wax inhibitor,EVA/PAMSQ compound wax inhibitor not only has a better effect of reducing the viscosity and viscosity of Changqing crude oil,but also has higher anti-wax efficiency.Its anti-wax efficiency for heat-treated Changqing crude at 60 ℃ is 77.9 %,which is significantly higher than that of EVA wax inhibitor which anti-wax efficiency is 62.3 %,but at the same time,it further improves the hardness and wax content of the wax wax layer of crude oil.In addition,the EVA/PAMSQ compound wax inhibitor makes the crystal morphology of Changqing crude oil more agglomerate.The Changqing blank crude oil and additive crude oil were pretreated at different heat treatment temperatures,such as 50 ℃,60 ℃,70 ℃ and 80 ℃.Then,the wax samples were tested for the wax deposition experiment and rheological experiment.The rules were found as followed:(a)The anti-wax effect of EVA/PAMSQ compound wax inhibitor is affected by the heat treatment temperature of crude oil.Under the condition of 50 ℃ heat treatment,the wax inhibitor has no anti-wax effect on Changqing crude oil;with the heat treatment temperature rises over 60 ℃,the anti-wax efficiency of the wax inhibitor decreases as the heat treatment temperature increases;Under the condition of 50 ℃ heat treatment,the wax inhibitor cannot increase the wax content of the wax deposits;with the heat treatment temperature rises over60 ℃,the ability of the wax inhibitor to increase the wax content of the wax deposits increases with the increase of heat treatment temperature.(b)The change of heat treatment temperature influences the wax deposition characteristics of the additive crude oil.Under the condition of 50 ℃ heat treatment,the wax deposit layer of the additive crude oil is soft,and the difference between surface and bottom layer properties is small.With the heat treatment temperature rises over 60 ℃,the wax deposit bottom layer is obviously delaminated on the surface layer;when the heat treatment temperature increases to 70 ℃ or 80 ℃,the wax deposit layer shrinks and becomes thin,and the surface and bottom layer cannot be distinguished.In addition,as the heat treatment temperature increases,the wax deposition rate of the crude oil decreases,and the average wax content of the waxed layer increases.(c)With the increase of heat treatment temperature,the viscosity and low-temperature gelling structure strength of the additive crude oil decrease;under the condition of 50 ℃ heat treatment,the wax inhibitor has no effect on the wax crystal morphology of Changqing crude oil.With the heat treatment temperature rises over 60 ℃,the wax inhibitor significantly improves the wax crystal morphology of Changqing crude oil.Wax deposition experiments were performed on blank crude oil and additive crude oil under different oil temperature,wall temperature,and rotational speed conditions,and then rheological experiments were performed on crude oil.the following regulations were obtained:(a)The anti-wax efficiency of EVA/PAMSQ compound wax inhibitor decreases with the forward movement of the temperature interval,the increase of temperature difference of oil and wall,and the rise of the flow rate.The increase in the wax content of the wax deposit increases with the forward movement of the temperature interval,the increase of the oil wall temperature difference,and the increase of the flow velocity.(b)Pipeline conditions will also affect the wax deposition characteristics of blank and additive crude oils.The deposition amount of blank and additive crude oil decreases with the forward movement of the temperature interval,and then increases first and then decreases as the oil wall temperature difference increases,and decreases as the flow rate increases;the wax content in deposits of the blank and additive crude oil increases with the forward movement of the temperature interval,the increase of the oil wall temperature difference,and the rise of the flow rate.(c)Wax deposition under different pipeline conditions shows different structural characteristics;under the cold rigime,EVA/PAMSQ wax inhibitor has no influence on the structural characteristics of wax deposit;under the hot rigime,the wax inhibitor has great influence on it.更多还原