基于EGO算法的常压塔能量优化

常减压装置能量消耗约占炼厂总用能的25%～30%,在保证产品产量与质量的条件下,优化常减压蒸馏塔操作条件,可有效降低能耗.为了避免随机优化算法对常压塔机理模型进行操作优化时,存在计算资源消耗大、效率低的问题,文中采用基于代理模型的全局优化方法优化常压塔的余热回收过程,在优化迭代过程中用Kriging代理模型来代替耗时的精确模型评估.实验表明模型调用次数相较于粒子群优化算法减少了90%,优化时间减少了85%,实现了能量优化并且保证了侧线产品之间的分离精度.     

常减压装置初馏塔侧线投用分析

常减压装置是炼化企业的重要组成部分，随着科学技术的发展，越来越多的企业开始投用初馏塔侧线以达到增产航煤的目的。某炼化企业3^#常减压装置加工混合原油8.0Mt/a，通过Aspen Plus进行装置的流程模拟及操作优化，确定了初馏塔侧线最佳抽出位置为第22块塔板，抽出量为16t/h，常压塔最佳取热比为塔顶+顶循∶一中∶二中=0.387∶0.233∶0.380。结果不仅使常二中增加取热8.11GJ/h，为后续换热网络优化提供了有利的条件，而且还在保证各侧线产品质量合格的基础上增产航煤16t/h，常压塔的拔出率也从35.5%提高到了36.3%。说明了常压塔在中段取热优化基础上，投用初馏塔侧线对航煤的增产效果较为明显，常压塔的拔出率也会增加。并且随着我国航空航天事业的飞速发展，市场对航煤的需求量日益提高。因此对于初馏塔侧线的投用具有很大的现实意义。     

Simultaneous optimization of heat-integrated crude oil distillation systems☆

Crude oil distil ation is important in refining industry. Operating variables of distil ation process have a critical ef-fect on product output value and energy consumption. However, the objectives of minimum energy consumption and maximum product output value do not coordinate with each other and do not lead to the maximum eco-nomic benefit of a refinery. In this paper, a systematic optimization approach is proposed for the maximum an-nual economic benefit of an existing crude oil distil ation system, considering product output value and energy consumption simultaneously. A shortcut model in Aspen Plus is used to describe the crude oil distillation and the pinch analysis is adopted to identify the target of energy recovery. The optimization is a nonlinear program-ming problem and solved by stochastic algorithm of particle warm optimization.     

Plantwide control for optimal operation of industrial-scale crude distillation unit processes

In this article, a combination of the wavelet neural network framework and the line-up competition algorithm is used to solve the economic optimization algorithm for an industrial-scale atmospheric distillation column (ADC) process. Compared to the relevant measuring data from Sinopec Wuhan Petroleum Group Company, China, the first optimal operating conditions show that the increments of the duties of furnace and pump-arounds of the ADC can effectively improve oil production. In our approach, the preflash column (PFC) coupled with ADC is denoted as an industrial-scale crude distillation unit (CDU) process. Since the PFC can produce light naphtha and reduce the furnace duty and steam consumption of ADC, it is verified that the CDU process provides the higher economic potential than ADC. Based on the second optimal operating conditions, the plantwide control strategy is employed to operate the system safely as well as regulate the outputs of the plant in the presence of inlet perturbations. Within the plantwide control framework, the inventory control aims to keep the controlled variables close to the desired operating condition and the quality control loops use a combination of inferential predictions and feedforward ratios to effectively suppress the temperature spikes of trays and furnaces. Finally, the simulations show that the product quality is guaranteed due to no offset ASTM D86 distillation temperature responses.     

基于特征选择的常减压装置模型及在计划优化中的应用

常减压装置将原油切割为不同中间产品,其作为炼油工艺的龙头装置,对炼油过程生产计划排产与效益提升至关重要。通过建立一种高精度且具有良好求解效率的常减压模型,用以求解模型关键指标实沸点（TBP）曲线,即综合考虑切割产品的实沸点（TBP）与原油TBP、流量、温度等变量影响,构建非线性方程组模型来表征输入输出间的关系;利用特征选择方法遴选相关变量（包括进料性质、相邻TBP及其二次项等）,并采用鲸鱼优化算法优化方程组系数。仿真结果表明,该多输出相互关系模型与已有文献工作相比,在兼顾求解效率基础上,常减压装置各蒸馏切割产品TBP曲线预测上有更高的精度,将此模型应用到炼厂计划优化中,与传统的悬摆切割模型对比,优化结果优于传统悬摆切割模型。     

环丁砜萃取精馏过程模拟分析及工艺参数优化

以环丁砜-烃类相平衡数据和NRTL-RK热力学方法为基础，对环丁砜萃取精馏过程进行了全流程模拟和工艺操作参数优化。综合考虑各个操作变量及其关联，提出了基于局部耦合参数迭代优化的整体协同优化的策略。通过文献数据回归和Aspen Plus物性估算系统相结合，补充修正了缺失的模型参数，并以此模拟分析了各关键操作参数对环丁砜萃取精馏过程能耗和分离效果的影响。结果表明：当萃取精馏塔操作压力为0.17 MPa，溶剂回收塔操作压力为0.05 MPa时，贫溶剂最佳温度为100℃，原料饱和气相进料的最佳进料位置为第50块塔板；溶剂回收塔最佳回流比为0.33；最佳进料位置为第6块塔板，汽提水量为2853 kg·h^-1。优化后，装置最小热公用工程由1.158 GJ·t^-1下降至0.802 GJ·t^-1，节能效果显著。     

常减压蒸馏装置的技术改造

介绍中国石化股份有限公司武汉分公司常减压蒸馏装置的技术改造特点及工艺流程,针对常压塔各侧线分离效果差、能耗高、产品分布不合理、轻质油收率低等问题,分别对常压系统、减压系统、电脱盐与精制系统进行改造。装置改造后,总拔出率提高了4.84%,轻油收率提高了3.59%,能耗降低了150.65MJ/t,产品分布趋于合理。     

A novel multi-effect methanol distillation process

Crude methanol distillation is an energy-intensive separation process and contributes significantly to the cost of methanol production. Although a number of energy-efficient distillation systems have been proposed, there is potential for energy savings in methanol distillation. To further reduce the energy consumption of methanol distillation, a novel five-column multi-effect distillation process is proposed in this work, which is essentially an improved version of an existing four-column scheme. The four-column scheme is made up of a pre-run column, a higher-pressure column, an atmospheric column and a recovery column. The new five-column scheme adds a medium-pressure column after the original higher-pressure column. In this way, the load of the original higher-pressure and atmospheric columns can be decreased by about 30%. The five-column arrangement creates a multi-effect distillation configuration involving efficient heat integration between higher-pressure and medium-pressure columns, atmospheric and recovery columns, and recovery and pre-run columns. Steady-state process simulation results indicate that temperature differences at two sides of each heat exchanger are appropriate, allowing effective heat transfer. Economic analysis shows that the energy consumption of the five-column scheme can be reduced by 33.6% compared to the four-column scheme. Significant savings in operating costs can therefore be achieved, resulting in an economically viable process for methanol distillation.     

Operational optimization of crude oil distillation systems using artificial neural networks

A new methodology for optimizing heat-integrated crude oil distillation systems is proposed in this work. The new procedure considers an artificial neural networks (ANN) model for representing the distillation column. Models of the distillation column and the associated existing heat exchanger network are incorporated in an optimization framework to systematically determine the operating conditions that improve the overall process economics. Of particular interest is the problem of optimizing the net value of the products obtained from the column by increasing the yield of higher-value products at the expense of less valuable products, while taking into account feasibility of the distillation specifications, heat recovery, energy and equipment constraints. A two-stage procedure is applied to first optimize the column operating conditions based on minimum utility requirements. In the second stage the heat exchanger network is designed.     

丙酮-水精馏过程模拟和优化

丙酮是一种广泛应用的有机溶剂,丙酮回收具有重要的经济和环境意义。丙酮回收过程中,需采用精馏单元操作进行分离提纯,精馏塔的模拟优化有着重要意义。文章采用Aspen Plus过程模拟软件,对精馏工艺进行了模拟核算,发现实际操作中精馏塔中存在着恒浓区,恒浓区的存在会带来精馏塔基建费用和能耗的增加。文章结合经济分析对丙酮精馏塔进行了优化,消除了恒浓区;同时,探讨了不同丙酮进料质量分数对精馏的影响,指出提高进塔丙酮质量分数是节能关键。     

稠油炼制减压蒸馏装置的扩能改造

介绍了自行开发的稠油炼制减压分离过程大型化关键集成技术。该技术成功应用于某石化公司第三常减压蒸馏装置,并使其处理能力从4.0 Mt/a提高到了6.0 Mt/a。改造完成后,各侧线产品质量均达到了质量控制指标,特别是作为加氢裂化原料的减二、减三线产品中Fe离子浓度降到0.3×10-6以下,取得了良好的效果,产生了可观的经济效益。     

基于能量目标的芳烃萃取精馏溶剂评价模型

以NRTL活度系数模型为基础，利用Aspen Plus对不同单组分萃取剂回收芳烃的萃取精馏装置进行了全流程模拟和工艺操作参数优化。综合考虑各操作变量及其关联，提出了基于局部耦合参数迭代优化的整体协同优化策略，在保证分离要求的条件下，以能耗为目标，对萃取精馏塔（EDC）、溶剂回收塔（ERC）的进料位置、ERC回流比等关键操作参数进行优化，建立过程能耗的物性关联模型。通过分析不同溶剂对芳烃萃取精馏过程能耗和分离效果的影响，提出了基于能耗目标的芳烃萃取精馏溶剂评价模型，结果表明影响芳烃萃取精馏过程能耗的关键物性为溶剂的分子量及常压沸点，所建立的过程能耗关联模型具有较高的关联性，其R ²均大于0.9，可有效指导萃取精馏溶剂选择，为计算机辅助分子设计提供简化的目标函数。     

基于多策略集成优化算法的己烷油精馏过程3E多目标优化

己烷油精馏工序是溶剂油生产过程的重要环节,但其伴随着高能耗和高排放。因此,己烷油精馏工序的能量、经济和环境（3E）多目标优化对于溶剂油工业的可持续发展具有重要意义。针对传统非支配排序遗传算法（NSGA-Ⅱ）收敛速度慢、易陷入局部最优等问题,本文提出了一种改进的基于多策略集成的多目标遗传算法（MENSGA-Ⅱ）。该算法发展了一种基于邻域的引导策略,以增强算法的搜索能力进而加快收敛速度;同时引入随机极限游走策略以维持算法所获得解集的分布性。将MENSGA-Ⅱ应用于典型的测试函数和实际的己烷油精馏过程,结果表明,该算法在鲁棒性、收敛速度和解集分布性上具有优越性。与实际运行工况相比,典型优化工况下精馏系统年度毛利润可提升4.99×10⁵USD/a,能源消耗和CO₂排放可分别减少5.09×10²kW/a和4.82×10²kg/a。     

加工俄罗斯原油常压装置设计中应注意的问题

哈尔滨石化分公司为适应原油品种的变化 ,在常压装置技术改造中 ,采用防腐措施 ,调整换热流程 ,换热终温比技术改造前提高 40℃ ;采用热管换热器回收热能 ,能耗较技术改造前平均低 12 5kJ/t原油 ;改造后的常压装置能炼制含硫 <0 5% ,含酸 0 5mgKOH/L原油     

蒸汽发生器在常减压装置中的应用

炼油装置对蒸汽的消耗是除了加热炉燃料油外的最大用能方式之一,炼油装置的低温余热利用是石化装置节能减排的主要工作思路,在常减压装置适当的工艺部位选择合适的热流作为热源,增加蒸汽发生器,再利用适当的低温余热提高换热终温,可替代原来的燃油蒸汽锅炉,节能减排效果显著,经济效益十分可观。     

3~#常减压蒸馏装置换热网络的操作优化

利用英国Process Integration Ltd.(PIL)公司最新的原油精馏系统优化技术,对茂名分公司3#常减压蒸馏装置换热网络进行建模及优化操作。结果表明,通过优化常压塔中段取热分配,将常顶冷回流量降到几乎为零,原油换热后温度提高了7℃,实现了能量回收最大化。     

分壁式精馏塔精制丁二烯流程模拟

丁二烯是一种重要的石油化工烯烃原料,由于其生产过程能耗高,因此节能降耗成为丁二烯生产工艺的研究热点。利用Aspen Plus模拟软件对丁二烯精制工艺的两套流程进行了模拟研究,考察了分壁式精馏塔(DWC)中内部互连物流连接位置、预分离塔气液相流量和回流比对分离效果和热负荷的影响,对比了相同分离条件下DWC分离流程和传统顺序分离流程的能耗,并根据两套分离流程中塔内液相丁二烯浓度分布情况,分析DWC的节能原因。结果表明,当主塔理论板数105,预分离塔理论板数56,进入预分离塔气相流量1020kmol/h,液相流量890kmol/h,回流比7800时,DWC分离效果最好,丁二烯质量分数可达99.7%,这为DWC精制丁二烯工艺的工业化提供了理论依据。由于DWC有效减少了精馏过程中的返混效应,提高了能量利用率,使其冷凝器可节能29.36%,再沸器可节能29.19%,存在明显的节能优势。     

甲基氯硅烷精馏流程的模拟与优化

采用Aspen plus软件对工业七塔精馏过程进行全流程建模与模拟，优化工艺参数，研究了新的精馏节能工艺。对一甲塔等7个精馏塔采用双因素水平的灵敏度分析，考察了塔釜采出率、回流比、进料位置和塔顶压力对产品浓度和热负荷的影响，确定一甲塔最优的工艺参数：塔釜摩尔采出率为0.92，摩尔回流比为130，塔顶压力为0.18 MPa，总理论板数为400，在210块理论板位置进料。在此基础上，针对高能耗的脱高塔/脱低塔，模拟研究了双效精馏新工艺，新工艺可节省39.70%的年总成本；针对一甲塔模拟研究了热泵精馏新工艺，新工艺可降低41.42%的年总成本。     

Dynamic process intensification: Fundamentals and implementation to ternary distillation

Distillation remains a key technology for separating liquid mixtures. Its versatility comes with the disadvantage of high energy consumption. We previously used empirical arguments to introduce dynamic process intensification (DPI) as a strategy for improving the energy efficiency of binary distillation. In this article, we focus on ternary distillation; we begin by providing a rigorous basis for DPI, then formulate the problem of identifying the operating states for DPI as a nonlinear optimization problem. Via an extensive case study considering a hydrocarbon mixture, we demonstrate that reboiler energy use can be reduced by more than 2.3% relative to an equivalent column operating at steady state. We prove that this result is due to the fact that DPI aims to satisfy product flow and quality constraints on average in time, affording broader opportunities for optimizing column economics than steady-state operation, where constraints are met strictly at all times.     

热泵精馏应用于异丁烷精馏过程的节能改造

异丁烷资源丰富,但工业利用率低,造成资源未得到合理利用。本文首先分析了C₃和C₄混合物分离体系的特点,建立异丁烷精馏常规工艺流程,并对其进行模拟计算。模拟结果表明:塔釜蒸汽消耗量较大,造成能耗过高。目前,解决精馏过程能耗过高的处理方式集中在工艺参数的优化,在精馏方式上却少有报道。为了解决这一问题,本文提出了采取热泵精馏技术进行节能改造,并建立了异丁烷精馏的热泵精馏新工艺。通过模拟计算且对结果进行深入分析,得出当塔顶/塔釜压力分别为7×10⁵Pa和7.5×10⁵Pa、循环工质流量3055.13kmol/h、压缩机压缩比为2.286条件下满足分离要求,且能耗较低。分析热力学效率与经济性并与常规流程进行对比,结果表明:热泵精馏新工艺节能效果极佳,由常规精馏的68.16GJ/h降低为热泵精馏的45.87GJ/h;热泵精馏新工艺适用于该体系且更加节能、环保。