氯乙烯聚合釜传热和操作参数设计计算

对于氯乙烯悬浮聚合釜传热设计和聚合过程操作参数选择问题，在建立氯乙烯引发剂浓度方程、传热模型、结构模型基础上，开发出一套计算机辅助设计程序，利用本程序可以有效便捷地计算出所需的聚合釜结构参数和工艺条件，为工程设计提供依据。     

工业聚合反应装置：Ⅳ.乳液聚合反应器（下）

讨论了釜式乳液聚合反应器搅拌桨的选择原则及其搅拌特性和乳液聚合反应器的放大准则，聚合过程的控制及其优化。     

DNTF合成反应器的模拟与设计

对DNTF合成氧化反应器进行了模拟和放大设计.根据反应体系的动力学特性和设备的传递特性,对反应器进行基础参数计算,确定了反应器的结构参数:如反应器体积、搅拌方式及转速、传热面积和换热方式等技术参数.将反应动力学模型和反应器热量传递结合起来,计算反应器的放热速率和热负荷,考察和分析反应器的能量和热量平衡,及反应器温度的波...     

Heat transfer characteristics of molten plastics in a vertical falling film reactor

The heat transfer efficiency during the pyrolysis process is a key factor to be considered in the design of pyrolysis reactors. In this study, the average apparent heat transfer characteristics of molten plastic pyrolysis in a vertical falling film reactor were explored by experiments and numerical simulation and the apparent heat transfer coefficients were determined. In addition, the temperature distribution and the thickness of the liquid film in the reactor were predicted and the influences of pyrolysis temperatures on the average apparent heat transfer coefficients were discussed.     

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。     

丁羟复合推进剂的辐射点火

采用CO2激光点火装置,对丁羟复合推进剂的点火过程进行了实验研究,利用描述固体推进剂物化现象的一维传热模型对复合推进剂的辐射点火特性进行了理论分析。通过最小二乘法拟合实验数据得到了丁羟复合推进剂的点火准则。结果表明,丁羟复合推进剂的点火过程主要包括惰性加热及气相点火过程,惰性加热时间和点火延迟时间随热流密度的增大而减小,且随着热流密度的增大,热流密度的影响逐渐降低。固相传热数学模型能够比较准确地描述复合推进剂的辐射点火特性。     

铝颗粒点火数值模拟

分析了准稳态铝颗粒在高温氧化剂中由于传热和表面的化学反应导致升温-熔化-升温-点火的过程，建立了铝颗粒点火模型，并对点火过程进行数值模拟。计算结果给出了对流传热、辐射传热、熔化热和异相表面反应热等对点火的影响。研究结果表明在点火过程中，铝的氧化在颗粒温度达到一定温度（T〉1000K）时才比较明显；点火时铝单质质量分数随环境温度的升高而略有增加，与颗粒尺寸无关；点火延时随着环境温度升高和颗粒半径的减小而缩短。     

合成橡胶聚合釜的技术进展

从聚合反应工程的角度对合成橡胶聚合釜的技术进行了评述,介绍了国外合成橡胶聚合釜搅拌技术的进展概况,并指出我国目前的开发重点为:a.刮壁式搅拌浆的工业化开发,特别是在顺丁橡胶聚合釜中的应用;b.同轴线双轴异浆异速组合式浆,特别是外层带刮板的组合粟的开发;c.适用于特高粘度体系,如本体聚合,聚合物的脱挥发分过程等的卧式单轴或双轴自清洁式搅拌装置的开发;d.沸腾换热技术和搅拌浆叶内通冷却介质技术在聚合釜领域的推广应用。     

Multistage two-membrane ATR reactors to improve pure hydrogen production

A plate-type auto-thermal reforming (ATR) reactor with both hydrogen permeable and oxygen permeable membranes has unique characteristics of mass transfer and heat transfer, which have a big effect on the hydrogen production and hydrogen recovery. In order to study the special mass and heat transfer inside the two-membrane ATR reactor, a 2-D reactor model was developed, and a reactor simulation was carried out. In the single-stage two-membrane ATR reactor, the large gradients of temperature and hydrogen concentration indicate the limitation of mass transfer and heat transfer. To improve the mass and heat transfer, multistage reactors are suggested. The simulation results show that the multistage reactors have better mass and heat transfer, a lower rate of oxygen consumption, higher operating temperatures of the H₂ membrane, and a larger driving force for hydrogen permeation, and hence can produce more than three times the amount of pure hydrogen than the single-stage reactor.     

不同聚合釜生产羧基丁苯胶乳的探讨

考察了１２．７ｍ＾３和１５．０ｍ＾３聚合釜在生产羧基丁苯胶中搅拌功率、搅拌级别、桨叶端速和传热能力以对聚合温度及产品质量的影响。结果表明，在传热能力强，搅拌级别适中的情况下，聚合温度容易控制，产品质量好，转化率较镐，能耗和物耗较低。     

A fast modeling of chemical reactions in industrial-scale olefin polymerization fluidized beds using recurrence CFD

We present a novel approach for the fast modeling of exothermic chemical reactions in industrial-scale fluidized bed reactors. It implicates a fast olefin polymerization process, accounting for the catalyst activity, the solubility of the reaction gases in polymer, the particles crystallinity, and the reaction masses and heat transfer. We principally apply the transport-based recurrence computational fluid dynamics (rCFD) model upon the base of a short-term non-reactive simulation performed by a coarse-grained two-fluid model (cgTFM). Following the captured recurrent flows, the methodology propagates rapidly passive scalars far beyond the recorded simulation. The reaction kinetics of production/consumption rates due to polymerization are locally embedded into the individual solid/gas species concentrations. These in turn are considered in transporting the enthalpy and the generated heat by reaction. By doing so, the significant computational effort required to couple the thermodynamic effects of polymerization with the cgTFM (hybrid model), is drastically reduced using rCFD with very reliable agreement.     

自由基聚合反应器中多尺度流场的模拟进展

自由基聚合过程中,由于混合、传递及聚合反应的相互作用使得反应器内部存在复杂的多尺度流场,例如宏观尺度的速度、浓度、温度分布,介观尺度的液滴粒径分布,微观尺度的聚合反应速率、聚合物分子量和多分散性指数分布。这些复杂的多尺度流场分布使得聚合反应器的模型化研究成为难题。本文较为系统地介绍了自由基聚合反应器中存在的多尺度现象;简述了微观尺度聚合物性质流场分布的模型化与模拟研究方法;从悬浮聚合和乳液聚合两个方面介绍了介观尺度液滴粒径分布的模拟研究进展;从非理想混合的角度阐述了宏观尺度多相流流场分布的研究进展。最后,本文分析了多尺度模型的耦合求解方法。本综述也有本文作者对这个领域的初步观点,可为聚合反应器的设计、优化和放大提供参考。     

SMI聚合反应釜传质及传热的研究

提出了SMI耐热改性剂在聚合反应前期的放热曲线,指出该反应的特点。在150 L的聚合反应釜内研究了影响SMI聚合反应的关键参数Pv、Np/Nqd及传热系数K,重现了小试试验的传热、传质结果。借助水运实验验证了经验公式计算传热效果的可靠性,理论计算值与实际值吻合较好,实现了聚合反应的可控性,为进一步放大研究提供了参考依据。     

工业聚合反应装置 Ⅵ．悬浮聚合反应器（上）

讨论了间歇釜式悬浮聚合反应器的搅拌、传热特点及其设备，介绍了典型的工业实例，并进行了工程分析。     

工业聚合反应装置 Ⅳ．乳液聚合反应器（上）

比较了乳液聚合用间歇聚合釜和连续搅拌釜式反应器操作中的反应工程特性，并根据这些特性介绍了间歇式和连续式乳液聚合反应器，除釜式外还有环管式和脉冲填料塔等新型反应器，同时还相应讨论了乳液聚合过程反应热的撤除以及传热设备。     

Modeling of the sheet‐molding process for poly(methyl methacrylate)

The sheet‐molding process for the production of poly(methyl methacrylate) (PMMA) involves an isothermal batch reactor followed by polymerization in a mold (the latter is referred to as a “sheet reactor”). The temperature at the outer walls of the mold varies with time. In addition, due to finite rates of heat transfer in the viscous reaction mass, spatial temperature gradients are present inside the mold. Further, the volume of the reaction mass also decreases with polymerization. These several physicochemical phenomena are incorporated into the model developed for this process. It was found that the monomer conversion attains high values of near‐unity in most of the inner region in the mold. This is because of the high temperatures there, since the heat generated due to the exothermicity of the polymerization cannot be removed fast enough. However, the temperature of the mold walls has to be increased in the later stages of polymerization so that the material near the outer edges can also attain high conversions of about 98%. This would give PMMA sheets having excellent mechanical strength. The effects of important operating (decision) variables were studied and it was observed that the heat‐transfer resistance in the mold influences the spatial distribution of the temperature, which, in turn, influences the various properties (e.g., monomer conversion, number‐average molecular weight, and polydispersity index) of the product significantly. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1951–1971, 2001     

Three-dimensional CFD model of the temperature field for a pilot-plant tubular loop polymerization reactor

A three-dimensional (3D) computational fluid dynamics (CFD) model, using an Eulerian-Eulerian two-fluid model which incorporates the kinetic theory of granular flow, the energy balance and heat transfer equations, was developed to describe the steady-state liquid-solid two-phase flow in a loop propylene polymerization reactor composing of loop and axial flow pump. The entire temperature field in the reactor was calculated by the model. The predicted pressure gradient data were found to agree well with the classical calculated data. Furthermore, the model was used to investigate the influences of the circulation flow velocity, the slurry concentration, the solid particle size and the cool water temperature on the temperature field in the reactor. The simulation results showed that the whole loop can be divided into four sections. In addition, the simulation results also showed that the continuous stirred-tank reactor (CSTR) assumption is invalid for the entire field in the loop reactor.     

PS反应器结构对产品质量的影响

从聚苯乙烯树脂连续本体聚合反应机理和反应器选型原理的角度出发，针对不同结构的本体聚合反应器，阐述了其结构形式聚合反应器的混合、传热性能以及产品质量的影响。     

Improvement of mass and heat transfer efficiency in a scale-up microfluidic mixer designed by CFD simulation

Due to scale effects, directly enlarging the size of the micromixer is an easy way to reduce the efficiency of mass and heat transfer in the continuous flow chemical process. It is urgently needed to solve the problem of mass and heat transfer efficiency of the scale-up mixer. A scale-up microfluidic mixer with a porous structure was designed to improve the mass and heat transfer efficiency using computational fluid dynamics (CFD) simulations. The effects of rotation angle, porosity, and baffle spacing were studied to optimize the mixer structure. Compared with the 1 mm mixer without structure, the scale-up mixer has a higher mixing efficiency and an 80% reduction in energy consumption at Re ≥ 700. A Nusselt number was used to evaluate the heat transfer efficiency of the mixer during fluid heating. The results show that the porous baffle promotes the generation of secondary flow and enhances the heat transfer effect, making its Nu increase by three times compared with the unstructured mixer. The scale-up microfluidic mixer with a porous structure can effectively improve the mass and heat transfer performance. This study can provide a reference for the design or development of a novel scale-up mixer.