常减压蒸馏装置中换热网络的模拟优化研究

发布时间：2018-04-15 04:29

本文选题：常减压蒸馏 + 换热网络　；参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：21世纪,能源问题已成我国,甚至全世界所面临的严峻挑战。其中,作为不可再生的能源:煤、石油以及天然气的贮备量愈加减少,消耗量却在不断增加。仅2014年一年,我国的原油消费量就高达五亿多吨,然而总产量仅为耗量的五分之二左右。另外,由于我国长期以来粗放型的经济增长模式,使得整个石化行业的能耗量巨大。在原油的炼制过程中,常减压蒸馏作为原油加工的第一道工艺,决定着原油加工品质的高低,其装置用能约占整个炼厂的四分之一。因此,常减压蒸馏装置的工艺水平对与企业的节能降耗、经济效益的增长有重要意义。目前,我国的炼化工业越来越注重装置的基础设计与优化改造。针对这一现状,本文拟使用Aspen plus模拟软件对常减压蒸馏装置的工艺流程进行模拟并对其换热网络加以优化设计,以此来实现化工过程全局用能优化。本次课题以惠州炼化常减压装置为研究对象。作为世界上第一座集中加工高含酸重质海洋油的炼厂,惠州炼化具备许多石化企业所没有的装置特点与工艺特点。另外,该炼厂的原油加工量为1200万吨/年,巨大的加工量使得实际生产中的常减压装置操作设备繁多,连接复杂。在建模前期,通过绘制其工艺原则图对实际流程进行适当的规划与调整,增加模拟计算的准确性。在模拟过程中,利用Aspen plus模拟软件根据原油性质、设计规定进行模拟参数的设定以选用适当的物性方法BK10,收敛算法WEGSTEIN,建立常减压蒸馏装置的操作模型。分别输入相应的工艺参数,对整个常减压工艺流程进行模拟。随后,提取出参与换热过程的工艺流股和公用工程流股的温度、流量、热量等操作数据,利用Aspen pinch模块对其换热网络进行模拟。确定系统的夹点温度,热回收量以及公用工程耗量。另外,为了验证所取夹点温差的正确性,取△Tmin为多个温度值,分别计算换热网络在该传热温差下的夹点温度以及公用工程耗量。绘制换热网络的栅格图,通过夹点计算可得实际换热终温与理论值有一定差距,从而该换热网络具有一定的改造潜力。根据夹点技术对换热系统的优化理论,提出改造方案:将换热网络分为脱前原油、脱后原油以及闪底油三个换热段,对其中违反夹点理论、存在改造潜力的流程段重新规划设计,确立新的换热流程。计算得改造后换热网络的换热终温得以提高,且装置的燃料气用量减少,系统的能量回收率提高。从而,改造具有一定效果,并可对实际操作产生指导作用。
[Abstract]:In the 21 st century, energy problem has become a severe challenge to our country, even the whole world.As a non-renewable energy source, coal, oil and natural gas reserves are dwindling and consumption is increasing.In 2014 alone, China's crude oil consumption reached more than 500 million tons, but the total output was only about 2/5 of the consumption.In addition, the energy consumption of the whole petrochemical industry is huge because of the extensive economic growth model in China.In the process of crude oil refining, atmospheric and vacuum distillation, as the first process of crude oil processing, determines the quality of crude oil processing, and its unit energy accounts for about 1/4 of the whole refinery.Therefore, the process level of atmospheric and vacuum distillation unit is of great significance to the energy saving and economic benefit increase of enterprises.At present, China's refining and chemical industry is paying more and more attention to the basic design and optimization of the plant.In view of this situation, this paper uses Aspen plus simulation software to simulate the process flow of atmospheric and vacuum distillation unit and optimize the design of heat transfer network, so as to realize the optimization of global energy use of chemical process.This topic takes Huizhou Refining and Chemical Atmospheric and vacuum Unit as the research object.As the first refinery in the world, Huizhou refinery has the characteristics of plant and process that many petrochemical enterprises do not have.In addition, the crude oil processing capacity of the refinery is 12 million tons per year, which makes the operation equipment of atmospheric and vacuum units in actual production numerous and complicated.In the early stage of modeling, the actual process is properly planned and adjusted by drawing the process principle diagram, so as to increase the accuracy of simulation calculation.In the course of simulation, according to the crude oil properties, Aspen plus simulation software is used to design and set up the simulation parameters in order to select the appropriate physical property method BK10 and the convergence algorithm WEGSTEIN to establish the operation model of atmospheric and vacuum distillation unit.The whole atmospheric and vacuum process was simulated by inputting the corresponding process parameters respectively.Then, the temperature, flow, heat and other operating data of process flow and utility flow are extracted, and the heat transfer network is simulated by Aspen pinch module.Determine the pinch temperature, heat recovery and utility consumption of the system.In addition, in order to verify the correctness of the pinch temperature difference, the pinch temperature and the utility consumption of the heat transfer network under the heat transfer temperature difference are calculated by using Tmin as several temperature values.By drawing grid diagram of heat transfer network, it is found that the actual end temperature of heat transfer is far from the theoretical value by means of pinch calculation, so the heat transfer network has a certain potential for transformation.According to the optimization theory of pinch technology for heat transfer system, the modification scheme is put forward: the heat transfer network is divided into three heat transfer sections: pre-desorption crude oil, post-desorption crude oil and flashover oil, and violates the pinch theory.The new heat transfer process is established by replanning and designing the process section with the potential for transformation.The calculated results show that the final heat transfer temperature of the heat transfer network is improved, the fuel gas consumption is reduced, and the energy recovery rate of the system is increased.Thus, the transformation has certain effect, and can produce the guidance function to the actual operation.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE96

【引证文献】