试论乙烯裂解炉裂解深度在线优化与应用

根据乙烯裂解炉在裂解深度方面存在的优化问题,本文从乙烯产品和丙烯产品的实际经济效益出发,合理制定了乙烯裂解炉在双烯收率上最佳经济效益的优化标准,只有完成该经济标准的优化,才可以在工艺参数和裂解原料不同的情况下,获得裂解炉在运行过程中的最佳裂解深度,真正实现经济效益的最大化。,     

先进控制技术在乙烯装置裂解深度控制中的应用

乙烯装置裂解炉运行状况直接关系到乙烯产品收率、装置能耗和生产效益。裂解深度是衡量裂解炉运行状况的重要指标之一,应用先进控制技术可以稳定裂解深度和相关参数。实施裂解炉深度先进控制技术后,"双烯"收率提高0.21个百分点,年创直接经济效益1 000万元以上。     

基于甲烷收率在线测量技术的乙烯裂解炉闭环优化方法

由于缺乏裂解产物收率绝对量信息,现有的乙烯裂解炉优化策略需要依靠裂解反应模型对裂解产物分布进行预测并依此进行开环优化计算,其优化结果完全依赖于裂解反应机理模型的精度.本文通过改进乙烯裂解炉裂解气取样系统实现了甲烷质量收率这一关键参数指标的在线测量,并在此基础上进一步提出一种裂解炉闭环优化运行新方法.该方法针对乙烯和丙烯收率和(简称“双烯”收率)最大这一优化目标,根据甲烷收率和双烯/甲烷比(烯甲比)的在线测量数据迭代求解获得最优炉管出口温度(COT).该方法采用闭环迭代寻优的方式,能够有效克服灵敏度函数的非线性以及在线分析仪表本身的测量误差,具有良好的鲁棒性;另一方面,由于不需要借助任何裂解原料与裂解反应模型,从而大大减少了裂解炉优化系统实施的投资,因此具有很好的工业应用前景.     

46万t乙烯装置裂解气分析在线色谱仪DRS改造

对46万t乙烯装置裂解炉裂解气分析在线色谱仪动态回流取样系统进行改造,解决乙烯裂解炉裂解气在线色谱仪投用率低的问题,保证裂解气在线色谱仪测量稳定准确,指导工艺精确控制裂解深度、提高双烯(乙烯、丙烯)收率。     

裂解炉操作条件对不同原料裂解收率的影响研究

简述了影响裂解收率的主要工艺参数及其相互关系,选择了乙烷、丙烷、丁烷、LPG、石脑油5种化工原料分别作为裂解炉的裂解进料,主要探究了不同辐射段炉管构型下的乙烯收率情况,简要分析了不同炉管构型、不同的裂解炉炉管出口温度(COT)以及不同的辐射段炉管出口压力(COP)对裂解收率的影响,分析了乙烯收率随关键组分转化率、丙乙比等表征裂解深度的指标的变化关系,为辐射段炉管的选型以及裂解炉操作条件的优化提供借鉴。     

裂解炉裂解产物优化方法

介绍了裂解炉裂解产物收率优化的4种方法：改善裂解原料、提高裂解深度、建立模型优化、采用先进控制技术优化。通过改善裂解原料和提高裂解深度虽能提高乙烯和丙烯收率，但这种优化更多依赖经验。人工智能优化方法只能反映裂解炉炉管出口裂解产物收率变化，而传统化工模型优化则更能反映裂解炉的整体运行情况。因此，采用传统化工建模优化方法与先进控制技术相结合，将是实现裂解炉产物收率优化的最佳选择。     

应用丙烷共裂解技术提高乙烯装置的经济性

从丙烷的裂解机理入手,介绍了丙烷作为乙烯装置裂解原料的优良裂解性能,当丙烷不具备单独裂解条件时,选择与石脑油共裂解也能提高乙烯收率。从理论上论述了实施丙烷共裂解的可行性,并介绍了北京东方石油化工有限公司东方化工厂乙烯装置在没有乙烷、丙烷裂解炉的条件下,通过技术改造实现了丙烷的回炼。通过选择合适的回炼方式有效降低了乙烯单耗,提高了双烯收率,为企业创造了巨大的经济效益。     

裂解深度过程控制技术的应用

介绍了吉林石化公司裂解装置采用基于先进控制技术的裂解深度过程控制系统的情况。自裂解深度控制系统成功上线运行以来,裂解深度波动范围控制在±0.02,裂解深度的在线估计误差小于3%,双烯收率增加0.12个百分点。同时裂解炉运行稳定性有所提高,取得了可观的经济效益。     

原料轻质化提高双烯收率

阐述了中韩(武汉)石油化工有限公司乙烯装置原料轻质化的工作背景。介绍了通过加大储运设施改造力度,提高轻质原料接卸能力;通过加大炼厂富乙烯气供应、多采购中石化沿江企业轻烃、碳五拔头油等资源,提高轻质原料加工比例;同时发挥新建H-009裂解炉裂解饱和液化气效果好的优势,优化乙烯装置生产组织,使得乙烯装置乙烯收率、双烯收率均创投产来新高,并取得良好经济效益。     

裂解原料裂解方案优化措施分析

针对裂解原料性质变化大的现状,独山子石化乙烯装置实施了如增设石脑油脱砷系统、改造轻烃汽化系统等一系列的优化措施。通过对裂解原料预处理系统的不断改造,提高了双烯收率,延长了裂解炉的运行周期。     

裂解炉炉管开裂原因分析

对发生失效破裂的炉管进行了宏观形貌分析、断口形貌分析、金相分析、有限元应力分析等 ,得出导致炉管破裂的主要原因是炉管在制造过程中产生缺陷引起的应力集中和特定的腐蚀环境共同作用下产生应力腐蚀断裂。     

Ozone cracking and flex cracking of crosslinked polymer blend compounds

Ozone cracking and flex cracking of crosslinked elastomer blends of brominated isobutylene/para‐methylstyrene copolymer (BIMSM) and unsaturated elastomers, such as polybutadiene rubber (BR) and natural rubber (NR), are studied. This saturated BIMSM elastomer, which is a terpolymer of isobutylene, para‐bromomethylstyrene, and para‐methylstyrene, functions as the ozone‐inert phase of the blend. Ozone cracking is measured by the failure time of a tapered specimen under a fixed load in a high severity ozone oven, whereas flex cracking is ranked by the De Mattia cut growth. The ozone resistance of BIMSM/BR/NR blends is compared to that of a BR/NR blend (with or without antiozonant) at constant strain energy densities. The effects of the BIMSM content in the blend, the structural variations of BIMSM, and the network chain length between crosslinks on these two failure properties, which are important in crosslinked compounds for applications in tire sidewalls, are discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2183–2196, 2007     

裂解炉出口温度控制技术的优化

通过对大庆乙烯装置80-U型裂解炉出口温度(COT)测量方式进行优化及改进,提高了对裂解深度的控制程度,进而改善了裂解炉日常的运行状况,达到了提高乙烯产品收率的目的。     

Production of steam cracking feedstocks by mild cracking of plastic wastes

In this work the utility of new possible petrochemical feedstocks obtained by plastic waste cracking has been studied. The cracking process of polyethylene (PE), polyethylene-polypropylene (PEPP) and polyethylene-polystyrene (PEPS) has been carried out in a pilot scale tubular reactor. In this process mild reaction parameters has been applied, with the temperature of 530 °C and the residence time of 15 min. The produced hydrocarbon fractions as light- and middle distillates were tested by using a laboratory steam cracking unit.It was concluded that the products of the mild cracking of plastic wastes could be applied as petrochemical feedstocks. Based on the analytical data it was determined that these liquid products contained in significant concentration (25-50 wt.%) of olefin hydrocarbons. Moreover the cracking of polystyrene containing raw material resulted in liquid products with significant amounts of aromatic hydrocarbons too. The steam cracking experiments proved that the products obtained by PE and PEPP cracking resulted in similar or better ethylene and propylene yields than the reference samples, however the aromatic content of PEPS products reduced the ethylene and propylene yields.     

碳氢燃料热裂解与引发裂解换热对比实验

通过流动管反应器对碳氢燃料RP-3在超临界条件下的热裂解及引发裂解进行了实验,对两种条件下的燃料吸热能力及传热特性进行了对比分析,并对裂解产物进行了采样分析。结果表明,引发裂解降低了燃料的裂解起始温度,在一定温度区间内提高了燃料的裂解率,从而有效提高了燃料热沉,在相同热通量条件下,降低了燃料温度,并降低了加热段壁面温度。对流换热受化学反应及物性变化的影响,燃料裂解吸热可增强换热,而大量气态产物的生成会降低换热,因此,裂解反应的增强不一定增强换热。     

Acid-catalyzed cracking of polystyrene

The effects of catalyst acidity and the restricted reaction volume afforded by HZSM-5 on the volatile cracking products derived from poly(styrene) are investigated. Three catalysts: silica/alumina, HZSM-5, and sulfated zirconia, were employed as cracking catalysts. Styrene, which is the principal radical depolymerization product from poly(styrene), is a minor catalytic cracking product. The most abundant volatile product generated by catalytic cracking is benzene. Alkyl benzenes and indanes are also detected in significant yields. Various thermal analysis techniques are employed to obtain volatilization activation energies for polymer-catalyst samples and to elucidate probable reaction pathways. Detected products are explained by reaction mechanisms that begin with protonation of poly(styrene) aromatic rings. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1287–1298, 1997     

裂解/烧焦切换操作的双辐射段裂解炉的数值模拟

用Gambit软件对双辐射段裂解炉进行几何建模和网格划分,选择计算流体力学软件Fluent的标准k-ε湍流模型、有限速率/涡耗散燃烧模型和P1辐射模型,对裂解炉辐射段和对流段进行数值模拟计算。模拟计算结果表明,裂解辐射段的烟气温度高于烧焦辐射段;在炉管中心面处,裂解辐射段的压力略高于烧焦辐射段,烟气流动的线速度明显大于烧焦辐射段;两个辐射段的炉管管壁温度分布不一致。尽管裂解辐射段的横跨段出口面烟气平均温度高于烧焦辐射段,但高温烟气没有流入烧焦辐射段且流向对流段的烟气温度场随着对流段高度上升逐渐均匀,该计算结果说明了双辐射段裂解炉的裂解/烧焦切换操作是可行的,并可进一步优化双辐射段裂解炉的结构和操作。     

催化裂化提升管反应器中颗粒聚团裂化反应的数值模拟

Behavior of catalytic cracking reactions of particle cluster in fluid catalytic cracking (FCC) riser reactors was numerically analyzed using a four-lump mathematical model. Effects of the cluster porosity, inlet gas velocity and temperature, and coke deposition on cracking reactions of the cluster were investigated. Distributions of temperature, gases, and gasoline from both catalyst particle cluster and an isolated catalyst particle are presented. The reaction rates from vacuum gas oil (VGO) to gasoline, gas and coke of individual particle in the cluster are higher than those of the isolated particle, but it reverses for the reaction rates from gasoline to gas and coke. Less gasoline is produced by particle clustering. Simulated results show that the produced mass fluxes of gas and gasoline increase with the operating temperature and molar concentration of VGO, and decrease due to the formation of coke.