含蜡原油管道蜡沉积特性及清防蜡对策研究

发布时间：2018-02-16 08:38

本文关键词： 含蜡原油清管周期余蜡厚度防蜡效果防蜡机理　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：管输含蜡原油的蜡沉积问题严重影响管道的安全经济运行,必须采取有效的处理措施。目前常用的方法包括清管和添加防蜡剂。虽然管道清防蜡技术的研究已开展多年,但目前对清管周期的确定仍没有统一的标准,多因素共同作用下防蜡剂的作用效果及机理等相关研究相对较少,因此有必要对其做进一步研究。文中主要开展了以下工作：基于主成分分析法,确定了蜡沉积各影响因素的权值；以中银线为例,利用黄启玉模型对不同运行条件下管道沿线蜡沉积层厚度进行了预测；以输量下降3%作为确定管道清管周期的安全极限,建立了管道安全经济清管周期模型；以降低日平均费用为目标,给出了一种确定余蜡厚度的方法；采用冷指装置,考察了不同剪切强度、温差和作用时间下防蜡剂对模拟油的作用效果及作用规律：利用X射线衍射分析仪和高温气相色谱仪,剖析了加防蜡剂前后蜡沉积量发生变化的原因；采用正交试验,分析了多因素作用下防蜡剂的作用效果,探讨了各影响因素之间的交互作用和主次顺序：通过测定晶格参数和碳数分布,研究了多因素共同影响下防蜡剂的作用机理。研究结果表明：管壁处剪切应力、粘度、管壁处蜡晶溶解度系数和管壁处温度梯度的权值依次降低,对蜡沉积速率起主要影响作用；当进站温度升高或降低时,相同运行时间下蜡沉积层厚度的最大值相差在0.087mm以内；地温越低蜡沉积层厚度的最大值越大；随进站温度的升高,日平均费用增加,清管周期延长,而输量和地温的增加使得日平均费用降低,清管周期下降；以输量下降3%作为确定管道清管周期的安全极限是合理可行的,可使得管道安全经济运行；中银线的余蜡厚度在0.4-0.6mm左右,每年可降低约7.5万元费用,但某些清管周期内也可不预留余蜡厚度；当壁温较低、油壁温差较大时,防蜡效果较好；剪切强度的增加会使得防蜡率出现先增加后降低的趋势,而随着作用时间的增加,防蜡率逐渐趋于定值；防蜡剂的共晶吸附作用改变了蜡晶的衍射峰强度和晶面间距等参数,使得蜡晶的生长更规则,蜡晶颗粒变大,由此发挥防蜡作用；加剂后油温和壁温的升高均会使得衍射峰强度降低,晶面间距增大,而随着作用时间的增加,其影响规律与油温升高时相反；剪切强度的升高使得晶面间距减小；壁温不变而油温降低时,常规碳数蜡的比例增大,而高碳数蜡的比例相对减少,壁温降低和剪切强度增大时的规律则相反；各影响因素对防蜡率影响的主次顺序依次为剪切强度、温差和作用时间,温差与剪切强度对防蜡率的影响显著；剪切强度、温差和作用时间之间的交互作用不是很明显；剪切强度、温差和作用时间的同时变化没有改变蜡晶晶型,但蜡晶晶格参数的变化规律与单因素作用下不同；多因素作用下蜡沉积物中正、异构烷烃碳数的分布范围、宽度及含量的变化规律与单因素作用下基本类似。
[Abstract]:The pipeline waxy crude oil wax deposition problems seriously affect the safety and economic operation of the pipeline, must take effective measures to deal with. The most commonly used methods include pigging and adding paraffin inhibitor. Although the study of pipeline wax removal technology has been carried out for many years, but now the Qing period on the tube is still no uniform standard, relevant study on the effects and mechanism of wax and anti is relatively less affected by many factors, so it is necessary to do further study.
This paper mainly carried out the following work: Based on principal component analysis method, the influence factors of wax deposition in silver weight; for example, the wax deposition along the pipeline thickness under different operating conditions were predicted by using the Huang Qiyu model; to output declined 3% as determined pipeline safety limit cycle of the cleaning pipe. The establishment of the safety of pipeline pigging cycle economic model; in order to reduce the average daily cost as the goal, this paper proposes a method to determine the thickness of the wax; the cold finger device, different shear strength study, wax agent on the simulated oil effect and effect of anti temperature and action time: Chromatography using X ray diffraction high temperature gas analyzer and analyzed, and anti change reason of wax deposition amount of wax before and after; using the orthogonal test, analyzed the effect of multiple factors of paraffin inhibitor, discusses the influence factors of Interactivity and primary and secondary order: by measuring the lattice parameters and the distribution of carbon number, the mechanism of the effect of wax inhibitor under the common influence of multiple factors was studied.
The results show that the wall shear stress, viscosity, wall wax solubility coefficient and tube wall temperature gradient in order to reduce the weight, effect on wax deposition rate; when the inlet temperature increases or decreases, the maximum running time under the same wax deposition thickness is less than 0.087mm the lower temperature; the wax deposition thickness bigger maximum; with increase of inlet temperature, the average daily cost increase, pigging period is prolonged, and increase the transmission capacity and temperature makes the average daily cost reduced, pigging period decreased to 3%; output declined as to determine the pipeline safety limit cycle tube is reasonable feasible, can make the pipeline safe and economic operation; silver line wax thickness is about 0.4-0.6mm per year, can reduce the cost of about 75 thousand yuan, but some pigging period can also be reserved without wax layer; when the wall temperature is low, the oil temperature Large, wax prevention effect is good; the increase in shear strength will make the wax rate increased first and then decreased, while with the time increasing, the wax rate gradually tends to a fixed value; eutectic adsorption paraffin inhibitor changes the wax crystal diffraction peak intensity and interplanar spacing and other parameters, the wax crystal growth rule, wax crystal particle becomes larger, thus play a wax; after adding the agent increased oil temperature and wall temperature will make the diffraction peak intensity decrease, increase the spacing, and with the time increasing, the influence of temperature and time on the contrary; shear strength with the increase of the crystal the surface spacing decreases; the wall temperature is constant and the temperature is reduced, the conventional carbon number of wax ratio increased, and the proportion of high carbon number of wax is relatively reduced, the wall temperature decreases and the shear strength of the law is the opposite; the influence of different factors on the order of the wax rate in turn As the shear strength, temperature and reaction time, temperature and shear strength had significant effects on wax rate; shear strength, temperature difference between time and interaction is not obvious; the shear strength, temperature and time of change at the same time has not changed but the change of the crystalline wax, wax crystal lattice parameters and single factor effect under different multiple factors; wax deposit is, the distribution range of isomeric alkane carbon number, variation of width and content and single factors were similar.

【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE832

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