常压蒸馏流程模拟与优化及换热网络综合

【作者】 张哲；

【导师】 卢涛；

【作者基本信息】 北京化工大学 ， 化工过程机械， 2009， 硕士

【摘要】 原油常压蒸馏塔的设计及操作的好坏对于炼油企业十分重要。近年来国内外原油蒸馏塔依靠技术进步,在装置工艺流程、节能及自动控制等方面均有不同发展。其中以工艺过程机理模型为基础,化工工艺模拟技术发挥了重要作用。本文采用化工模拟软件ASPEN PLUS对某炼油厂250万吨/年常压塔进行了模拟,得到了原油蒸馏过程各塔的操作数据,包括整个装置的物料平衡数据、消耗定额,初馏塔和常压塔的温度分布、压力分布及气液相分布,并将模拟计算产品的实沸点数据与标定结果进行了对比。模拟结果表明对常压塔的化工流程模拟真实地反映了装置的运行工况。在流程模拟的基础上,给定塔板数、原油进料流量、组分、侧线抽取参数以及常压塔各产品恩氏蒸馏温度为约束条件,以常压塔中段进料位置、中段循环参数、汽提蒸汽流量为优化决策变量,建立了以年综合收益最大为目标函数的优化模型。在ASPEN PLUS平台上进行二次开发,编写求解优化模型的FORTRAN程序,获得了良好的优化结果。从优化后流程中提取参与换热的冷热过程物流,运用夹点分析法对换热网络进行夹点分析,得到了各冷热流体在各自温度间隔的热负荷分布情况,绘制了组合曲线和总组合曲线。运用换热网络综合软件HEXTRAN求解换热网络数学模型,获得了无分流和有分流两种换热网络。考虑到原油常压蒸馏塔的长期投资性和换热网络灵活性,选择有分流换热网络。更多还原

【Abstract】 The design and operation of distillation column of crude oil are critical to petrochemical companies. In the recent years, technological process, saving energy and automatic control in distillation of crude oil attain huge development by technology advance. Chemical process simulation is based on mechanism of unit operation and it adopts mathematical method to simulate chemical technological process. In this paper, atmospheric distillation equipment of 25 million a year is simulated using simulation software Aspen Plus. The operation data of every column in crude oil distillation process are attained, including material balance data, consume ratio, distributions of temperature, pressure and vapor-liquid phase. True boiling point (TBP) data of simulation product are also compared with calibration data. The simulation results indicated that the process simulation reflected the real situation of the atmospheric distillation unit.Based on the flow simulation, taken tray numbers, flow rate of crude oil, components of crude oil, parameter of products and all products’ Engler distillation temperature of atmospheric distillation column as constraint conditions, taken mid-feed locations of atmospheric distillation column, cycle parameter of middle part of the column, flow rates of steam stripping as optimization decision variables, taken maximum annual net profit as objective function, optimization model is established. The model is solved by the second development of FORTRAN program on ASPEN PLUS platform. Expected optimization result is achieved.Data of cold and hot stream extracted from the optimization flow. Pinch analysis for heat exchanger network is completed. Duty distributions of cold and hot streams in different temperature intervals are obtained. Composite curves and grand composite curves are plotted. Mathematical model of heat exchangers network (HEN) is solved by the software HEXTRAN. The HENs with and without flow splitting are obtained. By consideration of the long period investment and flexibility of atmosphere distillation column, HEN with flow splitting is suggested.更多还原