聚丙烯环管反应器的模拟

以荆门石化总厂 7万t/a聚丙烯装置为基础 ,介绍了环管反应器特点 ,分析了物料在环管反应器中的流动特性 ,建立了符合其性能的数学模型。通过对模型的求解 ,得到了固含率、单体浓度、反应器温度、冷却水温度、聚合反应速率、链转移反应速率和催化剂失活速率等参数与环管反应器管长度的关系 ,为聚丙烯环管反应器的优化操作提供了理论依据     

聚丙烯环管反应器的模拟

以荆门石化总厂7万t/a聚丙烯装置为基础，介绍了环管反应器的特点，分析了物料在环管反应器的流动特性，建立了符合其性能的数学模型。通过对模型的求解，得到了固含率，单体浓度，反应器温度，冷却水温度，聚合反应速率，链转移反应速率和催化剂失活速率等参数与环管反应器管长度的关系，为聚丙烯环管反应器的优化操作提供了理论依据。     

BCH催化剂在PE环管中试上的试验

为考察BCH催化剂的性能及扩展催化剂的应用范围,北京燕化高新技术股份有限公司与美国Phillips石油公司合作,在后者的聚乙烯环管中试装置上,对BCH催化剂进行了性能评价.试验证明,BCH催化荆应用于环管反应器中具有较高的活性;通过改进加料方式,聚合反应操作平稳;在生产高密度聚乙烯时,完全可以在Phillips环管工艺上使用BCH催化剂.     

BOPP薄膜专用树脂的工业试生产

采用DQ-3催化剂,在液相本体双环管反应器中试生产了双向拉伸聚丙烯薄膜专用树脂T28C。生产中发现,催化剂氢调敏感性差、给电子体难计量、粒料和粉料熔体流动速率(MFR)偏差较大等问题。采用关闭第1环管反应器的氢气注入阀、只在第2环管反应器中加入氢气来合理分配氢气浓度;稀释给电子体浓度;在测试粉料MFR时适当加入抗氧剂,密切监控反应工况等方法解决了问题,生产出合格产品,且产品各项性能指标与国内同类产品相当。     

环管反应器内传热过程的数值模拟

为了对环管反应器内传热规律进行研究,在Euler-Euler双流体动量传递模型和环管反应器聚合传质模型的基础上,考虑了环管反应器内传热过程,建立了环管反应器传热数学模型,对工业烯烃聚合环管反应器内流动、传热和传质及聚合反应过程进行了研究。反应器内浆液温度的模拟值与工业现场值吻合,说明所建立的环管反应器传热数学模型是有效的。模拟结果表明,环管反应器温度与物料浓度存在不均匀分布。在上升段,温度分布呈中心对称,在弯管段不再呈中心对称,下降段的温度因弯管段的不均匀分布而不再呈中心对称分布;随着浆液入口速度或入口固体颗粒相体积分数的增加,环管反应器上升直管段,弯管段以及下降直管段温度降低;管壁冷却水温度不同,对环管反应器内冷却能力也不同,在反应器内相同的释放热量情况下,冷却水温度越低,对反应器内物料的冷却能力就越强。     

SPHERIPOL聚丙烯工艺环管反应器温度控制

Spheripol聚丙烯工艺生产过程中最大的风险因素之一是反应器温度过高,造成反应器内聚合物暴聚。因此,控制环管反应器的温度控制对Spheripol聚丙烯装置安全生产尤为重要。本文重点讨论影响环管反应器温度的因素,及环管反应器温度波动如何及时判断原因和采取相应调整措施。     

淤浆环管聚乙烯工艺反应器结皮原因分析及处理措施

随着社会的快速发展,聚乙烯的需求量越来越大,国内外聚乙烯生产装置也越来越多,淤浆法环管高密度聚乙烯装置成了主要生产高密度聚乙烯生产装置之一.在生产过程中,环管反应器经常出现结皮现象,严重影响了装置的正常运行.对淤浆法环管高密度聚乙烯工艺反应器结皮的原因进行分析,并提出了相应的处理措施.     

环管反应器轴流泵轴功率波动的分析

环管反应器轴功率波动,尤其为一环反应器轴流泵轴功率波动,此种现象在液相环管反应生产中表现尤为突出,并且一直困扰着聚丙烯行业,大庆30万t聚丙烯/年装置经首次开工成功后,至今已运行一年,期间多次出现环管轴功率波动现象,为此装置技术人员采取了多种措施,并进行了深入的分析.     

HDPE装置黏壁原因分析及处理措施

高密度聚乙烯环管淤浆工艺生产过程中会出现黏壁现象,反应器的黏壁是普遍存在的问题,这也是多种因素相互作用造成的。低聚物的生成、聚合温度高、静电、共聚单体等都有可能使反应器产生黏壁现象。通过合理控制共聚单体浓度,控制反应温度,保持反应器内壁光洁度,控制反应器内固含量等方法,可有效减少反应器黏壁概率,延长装置的运行周期。     

聚丙烯装置聚合单元运行问题分析及对策

分析了聚丙烯装置聚合单元催化剂预接触罐出料堵塞、预聚反应器温度波动、环管反应器反应波动等问题的原因,通过优化调整工艺参数,如针对环境温度调整主催化剂输送温度、催化剂预接触罐控制温度、处理预聚反应器测温电感探头等,使装置运行平稳,各项控制指标均达设计要求.     

Three-dimensional CFD study of liquid–solid flow behaviors in tubular loop polymerization reactors: The effect of guide vane

A three-dimensional (3D) computational fluid dynamics (CFD) model, using an Eulerian–Eulerian two-fluid model incorporating the kinetic theory of granular flow, is adopted to describe the steady-state liquid–solid two-phase flow under conditions employed in a tubular loop propylene polymerization reactor composed of loop and axial flow pump. The model is validated by comparing its simulation result with the classical calculated data as well as a set of data collected from certain pilot plant in China. The entire flow behaviors and the effects of guide vane on them in the reactor are also investigated numerically. Especially, the whole field in the loop reactor with the guide vane is obtained via the above model. The results show that a guide vane weakens the turbulent intensity, reduces the component of the rotating velocity, and contributes to the uniform distribution of the particles in the reactor. The second flow phenomenon is successfully predicted in the loop reactor with the guide vane.     

Investigation of a fixed-bed pilot plant reactor by dynamic experimentation. Part 1. Apparatus and experimental results

A non-isothermal, non-adiabatic fixed-bed pilot reactor specially designed for fast measurement of axial and radial temperature and concentration profiles during dynamic experiments is described. The pilot plant is interfaced to a process computer and facilitates conducting different types of dynamic experiments, such as those with simultaneous un-correlated periodic changes of the process variables. This type of dynamic experiments proved to be most efficient for collecting the data necessary for reactor modelling. Axial and radial temperature and concentration profiles in the fixed bed were measured during catalytic hydrogenation of toluene on an industrial nickel catalyst. Peak shaped perturbations were employed to study the parametric sensitivity of the reactor behaviour and to estimate the reaction kinetics.     

Biological treatment of waste water in the compact reactorDie biologische Reinigung von Abwässern im kompaktreaktor

A newly developed loop reactor has been shown to treat various domestic and industrial waste waters highly efficiently. In pilot studies BOD₅ capacities per unit volume as high as 28 kg m^?3 d^?1 have been achieved for domestic waste water. In treating the effluents from a paper factory the compact reactor gives the same degree of conversion for only 1/6 of the residence time of the factory's conventional effluent treatment plant.     

气相法聚乙烯中试装置流化床反应器的改进

运用流化力学的观点对流化床反应器进行分析和研究，并对影响流化状态的设备部件进行改进，解决了中试装置小反应器的运行问题。     

Scale-up of continuous flow stirred tank reactors

A model of a continuous flow stirred tank reactor based on laboratory experiments successfully describes the behavior of a pilot plant reactor. This model simulates the pilot plant performance over the full range of operating conditions: at high impeller speeds where performance approaches that of a perfectly mixed reactor and at low impeller speeds where performance significantly differs from perfect mixing. The micro-mixed feed model divides the continuous flow stirred tank reactor into a small micro-mixed impeller zone and a large macro-mixer.     

新型热管反应器在轻烃醚化中的研究及应用

将热管技术与催化反应器结合,构建了蛇形回路热管反应器。利用该反应器,进行了轻烃醚化工业侧线试验,考察了进料温度、液相体积空速、冷却水流量、进料浓度对反应结果的影响;测定了催化床层的轴向温度分布。利用反应器数学模型并结合试验数据,采用下山单纯形最优化方法获得了床层对热管的传热膜系数准数关联方程。所开发的新型热管反应器在2万t/a甲基叔丁基醚(MTBE)生产装置的扩能改造中应用成功。     

A homogeneous-heterogeneously catalysed reaction system in a loop reactor

Catalytic three-phase reactions including homogeneous liquid-phase steps were simulated in a loop reactor. The loop reactor consisted of a reaction vessel, an external loop as well as an ejector. The loop reactor was modelled using tanks-in-series or alternatively, axial dispersion models. Kinetics of the reductive alkylation of aromatic amines, which was determined from the experiments in a laboratory autoclave, was used for verifying the reactor model and for concentration profile simulations in the loop reactor.     

Design of a Flexible Pilot Plant Reactor for the Steam Cracking Process

A design technique for a pilot plant reactor of single diameter is presented to scale up or down steam cracking coils of different configurations like mono‐tubular, classical, and reversed splits. Using dimensional analysis, two criteria are selected in establishing partial similarity between different scales, the mean residence time, and the axial pressure profile in the reactor, in addition to preserving the flow pattern within the turbulent region. The sensitivity and accuracy of the proposed method is compared to another conceivable alternative that focuses on the lateral gradients. The pilot reactor coil is adapted for any large‐scale reactor by the adjustment of feed flow rate and the effective length exposed to the firebox heat flux. Simulation results for naphtha cracking in a commercial split coil and also the equivalent pilot plant reactors are used for verification and validation of this method.     

Cold Flow Model Study of an Oxyfuel Combustion Pilot Plant

The fluid‐dynamic behavior of a circulating fluidized bed pilot plant for oxyfuel combustion was studied in a cold flow model, down‐scaled using Glicksman's criteria. Pressures along the unit and the global circulation rate were used for characterization. The analysis of five operating parameters and their influence on the system was carried out; namely, total solids inventory and the air velocity of primary, secondary, loop seal and support fluidizations. The cold flow model study shows that the reactor design allows stable operation at a wide range of fluidization rates, with results that agree well with previous observations described in the literature.     

BULK POLYMERIZATION OF STYRENE IN A STATIC MIXER

An experimental investigation of thermal bulk polymerization of styrene in a pilot plant will be reported. The plant is composed of a recycle tubular reactor followed by a tubular reactor. The conversion of the pre-polymerization part is in the range of 0 to 60% and at the outlet of the pilot plant up to 96%. Studies on the residence time distribution show plug-flow behaviour for a variety of different conditions with respect to viscosity and density gradient. The polymers obtained are characterized by gel permeation chromatography and compared to commercial products.