Flowsheet Simulation for Bulk Propylene Polymerization Based on Polymers Plus

对于聚合物生产过程，建立一个既能反映聚合反应机理又能紧密结合装置运行的全流程模型，不仅有助于掌握装置运行的内在规律，而且是装置生产优化和提高经济效益的重要途径。 以国产化的Hypol丙烯本体聚合工艺为研究对象，分析工艺流程的主要组分和操作参数，采用PC-SAFT状态方程作为主要热力学模型；其次根据AspenTech的PolymersPlus软件特点，对工艺流程进行合理的简化和模型化，建立了包括液相聚合反应釜、釜顶蒸汽循环撤热、气相聚合反应器、气相循环撤热、丙烯单体冷凝回收等的流程模型。其中，丙烯聚合反应器是各生产工艺的核心技术，对其建模是流程模拟的难点与关键点。结合Hypol工艺各反应器的生...To develop a flowsheet simulation for industrial polymerization process, which can reflect the polymerization mechanism in essence and combine the unit operation closely, is not only helpful to master the inherence of the polymerization process, but also an important access to improve the plant’s performance and profit. The Hypol technology of polypropylene process was taken as background flowshe...学位：工学硕士院系专业：化学化工学院化学工程与生物工程系_化学工程学号：2062006115202

Cause analysis for fine power formation in the process for propylene polymerization in loop reactor

Spheripol环管工艺占我国聚丙烯生产能力的一半以上,该工艺具有转化率高、生产能力大等优点。然而,我国大多数环管装置均不同程度上存在生产过程中经常性出现细粉,影响产品质量以及造成生产不正常的缺陷。结合笔者多年相关的研究,对相关工艺细粉产生的原因进行分析,并提出了一些改进措施。The loop reactors process for propylene polymerization based on the patented Spheripol technology,has over half of the production capacity of polymerization in China,which has many characteristics including high conversion and throughput.Moreover,this technology has some disadvantages such asthe regular fine powder produced in the process for the propylene polymerization.According to authors' several years of works and lots of references,the reasons for the fine power produced in the loop reactors for propylene polymerization are summarized and analyzed in this paper

电学开路挠曲电悬臂梁自振频率分析

挠曲电效应是一种新兴的机电耦合效应,在微纳米尺度的传感器、致动器和俘能器方面有广阔的应用前景.本文基于挠曲电材料的变分原理和电吉布斯自由能,推导了表面覆盖电极的挠曲电悬臂梁在电学开路条件下的机电耦合动力学控制方程和相应的力电边界条件.进一步获得了求解电学开路条件下挠曲电悬臂梁自振频率的超越方程.以聚偏氟乙烯(PVDF)材料为算例,讨论了挠曲电系数、末端质量块和梁尺寸对结构自振频率和电学开路/短路条件下结构自振频率有效频移的影响.计算结果表明,挠曲电系数的增大会提高梁的自振频率;末端质量的增大可以降低梁的自振频率,并且末端质量块的转动效应对悬臂梁自振频率的影响很小;悬臂梁结构的有效频移随着结构尺寸减小而增加,并在某一厚度尺寸趋于饱和值.国家自然科学基金(11572271

MONTE CARLO SIMULATION of SINGLE-/MULTI-ACTIVE SITE CATALYSTS FOR PROPYLENE POLYMERIZATION

采用MOnTE CArlO模拟技术研究了在不考虑聚合物颗粒内物料与热量传递效应及不存在氢气作用下的单、多活性种类催化剂催化的丙烯聚合动力学。探讨了聚合产率、催化剂活性中心分率以及多分散指数随时间的变化规律,并对单、多活性中心种类催化的反应体系分别作了比较。基于MOnTE CArlO方法的模型得出的聚合动力学结果与文献相一致。此外,由MOnTE CArlO模拟也得到,催化剂多活性中心种类的性质对聚合产物的分布性质有很大影响;以多分散指数而言,多活性中心种类催化剂催化得到的聚丙烯多分散指数要比单活性中心种类催化剂催化得到的产物多分散指数宽。A Monte Carlo model was established to describe the propylene polymerization kinetics catalyzed by single-or multi-active site catalyst,ignoring the effects of intraparticle mass and heat transfer and the effect of hydrogen.Corresponding propylene polymerization kinetic data,including polymerization yield,concentration transformation of catalyst active sites,polydispersity etc.,were obtained via the model.Comparisons of the kinetic results between the polymerization catalyzed by the single-active site catalyst and the multi-active site type catalyst were conducted via the model.The simulated kinetic results are found to be in agreement with the reference ones obtained experimentally.The studied results showed that nature of multi-active site type could have a significant influence on polymer distribution properties.As of the polydispersity(PDI),polypropylene catalyzed by multi-active site type catalyst has a broader PDI than the one catalyzed by the single-site catalyst,under the same reaction circumstance.中国石油兰州石油化工研究中心课题(2007019);固体表面物理化学国家重点实验室(厦门大学)课题(200505)项目资

STEADY-STATE MODELING of COMMERCIAL LIQUID PHASE BULK PROPYLENE POLYMERIZATION

采用POlyMErS PluS软件对HyPOl聚丙烯工艺进行了模拟。建立了与现场流程及POlyMErS PluS软件均相匹配的模拟流程;采用PC-SAfT状态方程,并根据zIEglEr-nATTA催化体系的丙烯聚合机理,确定了丙烯聚合动力学。此外,通过文献提供的现场数据分析并确定了丙烯聚合动力学参数。最终建立了完整的HyPOl工艺流程模型。以采集的工业数据对模型进行验证,并采用模型考察了工业稳态操作下的主要工艺条件对丙烯聚合过程的影响。结果表明,模拟结果与工业现场采集数据比较吻合。随着H2进料量增加,聚合产品的熔融指数(MI)增大,数均相对分子质量(Mn)及其多分散分布指数(PdI)下降;催化剂及丙烯进料量的增加都将使各反应釜的聚合物产量增加。The HYPOL technology of polypropylene was simulated by Polymers Plus.First,a flowsheet which incorporates the actual technology into Polymers Plus was obtained.In addition,based on the perturbed-chain statistical associating fluid theory(PC-SAFT) and the propylene polymerization mechanism catalyzed by Ziegler-Natta catalyst,the propylene polymerization kinetics was obtained.Simultaneously,the polymerization kinetic parameters were obtained through the industrial dada provided via literature.Accordingly,the whole process model of the HYPOL technology was developed.The comparison between the simulated and plant data showed that they were in good agreement with each other.The model was also used to investigate the effects of the main operation parameters on the propylene polymerization under steady-state condition.The results indicated that the polymer melt index(MI) increased and the number average relative molecular mass(Mn) of the polymer and its polydispersity index(PDI) both decreased with the increase of the H2 flow rate.The polymer yield increased with the increase of the feed flow rate of catalyst and propylene.中国石油天然气股份有限公司兰州石油化工研究中心资助项

Intraparticle Mass and Heat Transport Model of Polypropylene in a Loop Reactor

针对环管反应器中zIEglEr-nATTA催化剂催化的聚丙烯颗粒增长过程,采用多层模型建立了聚丙烯颗粒内部的质量与热量传递预测模型。通过模型模拟得到聚丙烯颗粒内部的丙烯单体浓度梯度和温度梯度。此外,通过模型分析了聚丙烯颗粒的增长规律。结果表明,环管反应器中的聚丙烯颗粒内部的单体浓度梯度明显,该浓度梯度值随扩散系数的增大而减小,随催化剂初始粒径减小而减小;相比于浓度梯度而言,聚丙烯颗粒内部的温度梯度并不明显,温度值随聚合进行而增加,温度梯度则随催化剂初始粒径的增加而增加;不同大小的催化剂颗粒增长得到的聚丙烯颗粒的增长倍数不同。In the present study,the multilayer model(MLM)was used to describe the intraparticle mass and heat transport phenomena of polypropylene produced by propylene polymerization with the Ziegler-Natta catalyst in a loop reactor.Accordingly,the monomer concentration gradient and temperature gradient in the polymer particles and the rule of polymer particle growth were obtained based on the MLM.The results show that the intraparticle monomer concentration gradient is obvious,while the intraparticle temperature gradient is not so evident.Moreover,the simulated intraparticle monomer concentration gradient decreases with the increase of the value of the diffusion coefficient and decreases with the decrease of the original catalyst particle size.In addition,the intraparticle temperature increases with the increase of the polymerization time and the intraparticle temperature gradient increases with the increase of the catalyst original particle size.The results also show that the growth multiple of the polypropylene particle changes with the change of the original particle diameter of the catalyst.中国石油化工股份有限公司资助项目(x505029

ANALYSIS ON INFLUENCING FACTORS OF PARTICLE SIZE DISTRIBUTION IN PROPYLENE POLYMERIZATION LOOP REACTOR BASED ON PARTICLE POPULATION

在液相本体法环管反应器聚丙烯生产过程中,聚丙烯颗粒粒径分布影响聚合速率、气力输送、后处理工序生产成本和最终的聚丙烯物性,特别是对后续工序有流化床烯烃共聚的工艺有重要影响。为预测环管反应器中聚丙烯的粒径分布,考察各操作变量和动力学参数对聚丙烯粒径分布的影响,运用了粒群衡算方法。在综合分析环管反应器中物料流型、聚丙烯颗粒动力学和聚丙烯颗粒生长的基础上,建立了稳态操作时聚丙烯颗粒粒径分布预测模型。模型计算结果表明,当单一粒径催化剂进料时,随着催化剂粒径或是预聚合与主聚合反应温度的增加,聚丙烯粒径分布向大粒径方向偏移,且分布变宽;相比于反应温度,催化剂粒径作用更为显著。同时发现,丙烯进料流速对聚丙烯粒径分布的影响很小。在催化剂粒径有分布的情况下,不同粒径催化剂的质量比不但影响聚丙烯的平均粒径,而且也影响其粒径分布曲线,并在一定的质量比下会出现双峰颗粒粒径分布曲线。In a propylene polymerization loop reactor,polymerization rate,fluid transport,and cost of post-treatment after polymeric process and polymer properties may be affected by polymer particle size distribution,especially when a co-polymerization technology including olefin polymerization fluidized-bed reactor is followed.In order to investigate the effects of operation parameters and kinetics parameters on the polypropylene particle size distribution in the loop reactor,a steady-state particle size distribution model was developed,in which the flow type in the loop reactor,polypropylene particle dynamics and the particle growth were taken synthetically into account based on the mass balance and solid population balance.The result showed that for uniform size catalyst feed,by increasing either initial catalyst size or the reaction temperature of the main polymeric reactor,the polypropylene particle size distribution in loop reactors became boarder and shifted to larger size,in comparison with the reaction temperature,the effect of catalyst particle size was obvious.The effect of propylene feed rate on polypropylene particle size distribution was much smaller.It's also shown that the ratio of catalyst masses with different sizes in the case of multi-size catalyst feed strongly affected not only the average polypropylene particle size,but also the particle size distribution in the loop reactor.Bimodal polypropylene particle size distribution can be obtained by using a catalyst feed with a distinct particle size distribution.国家自然科学基金(20406016);; 中国石油化工股份有限公司福建炼油化工有限公司项目(G7808-06-ZS-1006)资

MODELING of LOOP REACTOR FOR POLYPROPYLENE SPHERIPOL TECHNOLOGY

在ASPEn POlyMErS PluS软件平台上模拟SPHErIPOl聚丙烯工艺中核心液相环管反应器,采用了等效的全混流反应器模型和组合式环管反应器模型,结合工厂现场采集的数据,拟合了丙烯聚合反应动力学模型,并将该模型用于2种环管反应器模拟方法的比较。采用组合式环管反应器模型考察了丙烯聚合反应循环比对反应器撤热、聚丙烯产量和相对分子质量分布、反应器内氢气浓度分布的影响。结果表明,在高循环比操作条件下和误差允许范围内,环管反应器可以等效为一个全混流反应器。当控制环管反应器夹套冷却水出口温度不变时,过低的循环比使得反应器内的温度分布不均匀,而过高的循环比则使环管反应器的撤热能力下降;当循环比增加时,环管反应器内的温度和组分浓度梯度减小,停留时间分布均匀,趋于全混流状态,催化剂活性得到充分发挥,聚丙烯产量也相应增加。Both the continuous stirred tank reactor model and the combined tubular loop reactor model were set up to simulate the steady-state performance of the industrial tubular loop reactor of Spheripol technology of propylene polymerization based on the Aspen Polymers Plus software.A comprehensive catalyzed polymerization kinetic model was verified by using plant data,and was employed to analyze the operational performance of the two models.It was observed that in high recycle ratio for propylene polymerization,the tubular loop reactor could be simulated,to a certain error degree,by a continuous stirred reactor.In addition,the effects of recycle ratio on the performance of the loop reactor could also be obtained via the combined model.The simulated results showed that the low recycle ratio made the temperature change along the tubular loop reactor in a large range under the constant coolant outlet temperature,while the high recycle ratio made the reaction temperature uniform in the tubular loop reactor,but the capacity of heat evacuation reduced.On the other hand,with the increase of recycle ratio,the concentration gradients of reaction components were lowered,and the polypropylene production was enlarged,approaching to the performance of the continuous stirred reactor.中国石油天然气股份有限公司兰州石油化工研究中心项目(2008015)资

Comparison of efficacy between mPCNL with holmium laser and EMS standard tract PCNL in the treatment of complex renal calculi under ultrasound guidance

目的比较b超引导下微通道经皮肾镜钬激光碎石术(MPCnl)与标准通道经皮肾镜气压弹道联合超声碎石术(标准通道PCnl)治疗复杂性肾结石的临床疗效。方法对78例复杂性肾结石患者分别行MPCnl(35例)和标准通道PCnl(43例)治疗,术后对2组患者的手术时间、一期结石清除率和手术并发症等指标进行比较分析。结果 2组患者分别成功建立16f和24f经皮肾通道并一期行碎石术。MPCnl组手术时间明显长于标准通道PCnl组;一期结石清除率MPCnl组低于标准通道PCnl组,差异均具有统计学意义(P均38.5℃1例。2组并发症差异无统计学意义(P>0.05)。结论 b超引导下MPCnl与标准通道PCnl治疗复杂性肾结石安全有效、并发症发生率低,标准通道PCnl联合应用EMS第4代气压弹道联合超声碎石清石系统碎石清石效率高,较MPCnl钬激光碎石明显有优势,值得推广。Objective To compare the outcomes of the surgical treatment of complex renal calculi with minimally invasive percutaneous nephrolithotomy(mPCNL) and EMS percutaneous nephrolithotomy(standard tract PCNL) under ultrasound guidance.Methods A total of 78 patients with complex renal calculi were allocated to either mPCNL treatment group(mPCNL group,n=35) or EMS(swiss,the fourth generation) standard tract PCNL treatment group(standard tract PCNL group,n=43).The operative time,primary stone-free rate and operative complications in the two groups were compared.Results 16F and 24F percutaneous renal accesses were successfully established in mPCNL group and standard tract PCNL group respectively,and then the first lithotrity-lithiasis cleaning procedure was performed.The operation time in mPCNL group was longer than that in the standard tract PCNL group 〔(102±31) min vs(67±22) min,P38.5 ℃ occurred in one case of mPCNL group.There was no significant difference in operative complications in two groups(P>0.05).Conclusions Both the treatments of complex renal calculi with mPCNL and EMS(the fourth generation) standard tract PCNL under ultrasound guidance are similarly safe,but the standard tract PCNL has the superiority of higher primary stone-free rate and shorter operation time over the holmium Laser mPCNL.Therefore the standard tract PCNL merits propagation for treating complex renal calculi