常减压蒸馏是炼油加工的第一道工序，其水平的高低直接关系到原油的有效利用，对全厂的产品质量、产品收率、经济效益有很大影响。对常减压进行流程模拟与优化，日益受到关注，从研究机理建立数学模型到利用成熟模型进行装置核算，都开展了广泛的研究，取得了显著的成效。目前，对于常减压蒸馏装置模拟研究多集中在精馏塔，而对全流程模拟的较少。本文运用ASPEN PLUS软件，对大庆石化公司一套常减压装置进行了全流程模拟，建立了包括初馏塔、常压塔、减压塔以及换热流程在内的基础模型，得到关于装置物料平衡、能量平衡、产品质量等的详细数据，模拟结果与实际相符合。在基础模型的基础上，建立了设备核算模型。对塔进行水力学计算，得到了每块塔板上的液泛因子等参数，能够评价塔的运行情况，为装置提高加工量、改变操作条件提供依据。建立了装置工况研究模型，利用灵敏度分析方法，研究了中段回流、侧线采出对产品质量的影响。通过工况研究功能，能够直观地、定量地分析装置各个关键参数对装置操作的影响，综合各种因素，找出较优的操作参数，进而改善装置的操作。利用所建立的模型，研究了减压炉温降低对减压塔运行工况、产品质量的影响，给生产方案的调整提供了理论依据。模拟结果表明：减压炉降低操作温度后，侧线产品收率、质量能够满足生产要求；加热炉、塔顶热负荷大幅降低，塔顶冷凝器所需冷量降低，可以采用循环水进行冷却，从而降低装置的能耗。
Atmospheric-vacuum distillation is the first process of crude oil processing, which level is directly related to effective utilization of crude oil and which has great influence on product quality、product yield and economic benefit of refinery plant. Process simulation and optimization of CDU has been paid attention, and study on process simulation and optimization of CDU has been developed from mechanism research 、establishing mathematical model to calculating operation parameters by mature model, successful effect has been achieved. At present, more simulation studies of atmospheric and vacuum distillation unit concentrate on distillation column, little study about whole process simulation of atmospheric and vacuum distillation unit.This paper is about whole process simulation of No.1 CDU of Daqing petrochemical company by ASPEN PLUS software, by establishing basic model of primary distillation column、atmospheric distillation column、vacuum distillation column and heat exchange process, detailed data is obtained about material balance、energy balance and product quality, simulation results are close to actual experiences.On the base of basic model, equipment accounting model is established. Hydraulic calculation is made for column, obtaining liquid flooding factor on every tray, which provide evidence for analyzing the operation of column under normal load、expanding the processing capacity for unit and changing operation conditions.Research model is established for working condition, studying the influence of pumparound and side withdrawing on product quality by The sensitivity analysis method. The influence of every key parameter on the operation of unit can be analyzed visually、quantitatively by studying the working condition. By integrating various factors, the optimal operating parameters are found in order to improve the operation of unit.Using the established models, the study is made for the influence of decrease of vacuum furnace temperature on working condition of vacuum distillation column and product quality, which provides theoretical basis for adjusting production scheme. Simulation results show yield and quality of side product can meet production requirement after decreasing the operating temperature. Great decrease of thermal load of heating furnace and overhead leads to decrease of cooling capacity needed by top condenser which can meet by circulating water so that energy consumption of unit can be reduced.
