原油罐储过程传热与流动特性描述及有效能利用评价研究

发布时间：2018-02-14 13:12

本文关键词： 原油浮顶储罐蒸汽盘管加热周期性边界条件加热效果评价用能有效利用率　出处：《东北石油大学》2017年博士论文　论文类型：学位论文

【摘要】：随着我国原油战略储备需求的增加,大型浮顶油罐因其技术和经济上的优势已成为大规模原油库的首选储油设施。油罐在生产运行中,当罐内原油温度低于析蜡点时,含蜡原油会因析蜡在浮顶、罐壁和罐底所包围的内沿形成一定厚度和强度的凝油层,严重时可能发生凝罐等生产事故。因此,为确保储罐安全经济运行,必须准确掌握罐内原油温度场以及流场的变化规律。数值模拟是研究罐内原油场分布的主要方法,但往往将边界条件简化为定解条件处理,无法反映储罐传热过程中太阳辐射、大气温度等周期性边界条件对罐内原油温度场、流场的实际影响。另一方面,随着储罐规模向大型化发展,加热耗能逐渐增加,对加热效果以及用能情况的研究将十分必要。基于以上,本文开展了原油罐储过程传热与流动特性描述及有效能利用评价研究。首先,根据传热学相关理论,研究大型浮顶储罐边界条件的数值处理技术,分析了大气温度、太阳辐射等周期性变化条件下储罐边界传热系数随时间的变化规律。在此基础上,建立了大型浮顶原油储罐静储过程包括连续性方程、动量方程以及相应流态方程在内的理论模型,并对其进行数值求解,深入分析环境、生产运行工况对储罐静储过程传热与流动耦合特性的影响机制,依据原油温度场的变化规律,将静储温降过程分为局部快速温降阶段、整体快速降温阶段、凝油层增长阶段和整体低速降温阶段,温升过程分为局部低速升温阶段、局部快速升温阶段。然后,在对静储理论模型实例验证基础上,综合考虑环境温度、太阳辐射、加热蒸汽压、油品物性参数等因素,建立了大型浮顶原油储罐蒸汽盘管加热过程理论模型,数值研究原油温度场与流场的变化规律,将加热过程分为自然对流生成阶段、小涡旋的形成阶段、大涡旋的形成阶段以及大涡旋的发展阶段。通过分别模拟竖排盘管、立体盘管以及蛇形盘管的加热工况,揭示盘管结构对储罐加热过程中原油传热与流动耦合特性的影响机制,深入分析罐内油品液位、加热蒸汽温度、外界环境条件等因素对罐内原油温度场、流场的影响规律。分别从时间和空间的角度出发,提出了储罐加热过程加热效果的评价指标,分析了不同结构蒸气盘管加热过程升温速率和温度场不均匀程度的变化规律。根据热力学第一、第二定律,同时考虑能量和能质的属性,提出了储罐原油加热过程用能评价指标,分析了不同结构蒸汽盘管加热过程中的能量损失以及?损失情况,揭示?传递速率与?传递动力、阻力之间的关系,研究罐内油品液位、盘管热流密度、外界环境条件等因素下能量有效利用率、?有效利用率的变化规律,可为油田企业如何提高储备能源利用效率提供理论支持。最后,在得出蛇形结构盘管加热油品具有升温速率快,温度场均匀度好,能量有效利用率以及?有效利用率高等优点的前提下,以蛇形结构盘管为研究对象,运用Visual Basic 6.0语言开发了“浮顶储罐蛇形盘管工艺设计软件”,软件包括原始数据录入模块,数值传热计算模块以及相应的计算结果输出模块,得到包括储罐传热系数、罐内原油温度场,油品升温吸收热量、罐壁表面散失热量及加热油品总热量等相关结果,可作为储罐盘管加热工艺计算的辅助工具,为相关研究设计人员提供一定的技术参考。
[Abstract]:With the increasing demand of China's strategic oil reserves, oil has become the preferred storage facilities of large-scale crude oil because of its technical and economic advantages of large floating roof tanks. During the operation, when the tank is lower than the temperature of crude oil wax precipitation point, waxy crude oil because of the wax in the floating roof tank wall and a tank. The bottom surrounded along the formation of a certain thickness and strength of the condensate reservoir, which can produce condensate tank production accidents. Therefore, in order to ensure the safety and economic operation of the tank, the tank must accurately grasp the crude oil temperature field and flow field were studied. The numerical simulation of oil tank field distribution is the main method, but often will the boundary condition is simplified as boundary conditions, can not reflect the heat transfer process in tank solar radiation, air temperature, periodic boundary conditions on the oil tank temperature field, the actual effect of flow field. On the other hand, as to the large scale storage tank The development of heating energy consumption gradually increased, the heating effect and energy research will be necessary. Based on the above, this paper carried out the crude oil tank process of heat transfer and flow characteristics of description and effective utilization evaluation research. Firstly, according to the theory of heat transfer, numerical processing technology of large floating roof tank boundary conditions, analysis the air temperature variation of heat transfer coefficient of tank boundary periodic variation of solar radiation conditions with time. Based on this, a large floating roof oil storage reservoir static process including continuity equation, momentum equation and the corresponding theoretical model, flow equations, and the numerical solution of in-depth analysis, environment, influence the mechanism of operating condition of static flow and heat transfer process on the coupling characteristics of storage tank, based on the variation of crude oil temperature field, the static storage temperature decreasing process is divided into local rapid temperature Drop stage, the overall rapid cooling stage, growth stage and the overall low condensate oil cooling stage, the temperature rise process into local low temperature stage, rapid local heating stage. Then, in case of static verification based on the theoretical model of reservoir, comprehensive consideration of environmental temperature, solar radiation, heating steam pressure, oil property parameters etc. the factors, established a theoretical model of large floating roof oil tank steam coil heating process, variation of numerical study of oil temperature field and flow field, the heating process is divided into natural convection generation stage, formation stage of small vortex, the stage of formation and development stage of large eddy and large eddy simulation respectively. Through vertical coil, coil and stereo coil tube heating conditions, reveals the influence mechanism of tank coil structure in the process of heating oil flow and heat transfer coupling characteristics, in-depth analysis of oil tank, heating steam temperature Degree, environmental conditions and other factors on the oil tank temperature, influence of flow field. From the angle of time and space, this paper put forward the evaluation index of tank heating process for the heating effect, analyzes the different structure of steam coil heating process, the heating rate and the temperature field of non-uniformity variation. According to the first second. The law, considering the property of energy and energy quality, puts forward the evaluation index for crude oil tank heating process, analyzes the different structure of the steam coil heating in the process of energy loss and loss situation, reveal?? transfer rate and the transmission power, the relationship between the resistance? The oil level of the tank, the coil heat flux, the outside world the environmental conditions of energy efficiency, effective utilization rate? Changes, for oilfield enterprises how to improve the utilization efficiency of energy reserves and provide theoretical support. Finally, in The structure of serpentine coil heating oil has faster heating rate, temperature field uniformity, the effective utilization rate of energy and? The effective use of the advantages of high rate of the premise, to coil snake structure as the research object, using Visual Basic 6 language has developed a "floating roof tank coil tube process design software, software includes the original data entry module and the corresponding calculation module, output module of calculation results of numerical heat transfer, including tank heat transfer coefficient, temperature field of crude oil tank, heating oil tank wall surface to absorb heat, heat dissipation and heating oil heat and other related results, auxiliary tools can be calculated as the tank coil heating process, provide technical reference for related research. Design personnel.

【学位授予单位】：东北石油大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TE972

【参考文献】