径向流反应器的研发和应用

全面介绍了径向流反应器的结构和特点,总结了变质量流动规律、流道静压分布规律、动量交换系数和穿孔阻力系数的研究成果,特别介绍了新型轴径向流反应器及其催化剂封区的二维流特征、大型冷模开发研究和数学模型。提出了径向流反应器在不同化学工艺中的特点、分类及其应用,并对径向流反应器的大型化趋势作了展望。     

径向反应器流体均布的研究

本文报告了径向反应器流体均布条件的研究情况。针对径向流体分布的主要问题,测定了分、合流情况下穿孔阻力系数以及主流道动量交换系数。并简述了应用于径向反应器或径向流动设备中分布器设计的计算方法。     

多床层径向反应器中床层的流场行为

在直径3m、高5m的大型多床层径向反应器冷模装置上,通过测定流体在流道和各分床层内的静压分布,考察了各分床层的流体流动行为和特征.结果表明,当流道静压差的均方根偏差小于1%时,各分床层静压差的均方根偏差小于5%,流体在各分床层的径向流速沿轴向分布均匀,流速最大偏差小于5%;当流道静压差沿轴向的差别大于10%时,则其沿轴向分布显著不均匀,且靠近流道静压变化梯度大的分床层的径向流速均匀性最差,床层上下端流速偏差达70%.Π型流动形式是动量交换型径向反应器的最佳选择,适宜的两流道静压差设计可实现径向流速沿床层轴向完全均匀分布。     

垂直多孔道中的变质量流动

导出了在垂直圆形多孔通道中的分流和合流流动含重力项的动量交换方程. 通过大型冷模实验，得出了分流、合流在向上流动、向下流动时的静压分布和虚拟压强分布，应用黄金分割法进行一维搜索，得出了实验条件下分流、合流的动量交换系数为0.77和1.26，平均相对误差分别为10%和15%. 结果说明表观气速较小时，重力的影响不能忽略.     

列管反应器中环形分布器内流体均布的探讨

利用动量守恒原理,推导出列管反应器中环形分布器内流体流动的修正动量方程,并在与前人实验结果比较和分析的基础上,提出了与环形分布管相适应的分流和合流动量交换系数式。研究结果表明,环形分布器内流体流动符合变质量流动规律,可采用环形分布器修正动量方程描述分流和集流的静压变化;通过直管分布器实验获得的动量交换系数对环形流道分布器也是适用的,其计算值与实验值的相对误差小于10%,可满足工程设计要求。     

径向反应器流体均布设计的研究

本文探讨了径向反应器流体均布设施的合理设计。流体在主流道的动量可以用修正动量方程来描述 dp+2k(γ/g)wdw+(λ γw_2/D_e 2g)dx=0 这里P、γ/g、w、λ、D_e和x分别指流体静压、流体密度、主流道流速、管摩擦系数、主流道当量直径、主流道长度。动量交换系数k已经被测得。分流流道动量交换系数在0.65—0.72之间。集流流道k值稍大于1。分析了主流道的静压分布。在分流流道中,按照摩阻项和动量交换项的相对大小提出了四个流动模型。 条件 模型 λL/（6D_ek）1 动量交换控制 λL/（6D_ek）1 摩阻控制 λL/（4D_ek）<1 动量交换占优势 λL/（4D_ek）>1 摩阻占优势在分流流道中。由于动量交换项和摩阻项对静压有相反的影响,所以静压变化趋势依赖于各种模型。但是,在集流流道中,它们的影响是一致的,而总是使静压趋于下降。为了降低径向反应器中分、合流流道间静压变化的差异,当分流流道受动量交换所控制或动量交换占优势时,采用“Ⅱ”型分布是合理的。相反,如果分流流道受摩阻控制或摩阻占优势时,则“Z”型分布将是合适的。根据各种流动模型,推荐了分流流道与集流流道合适的截面比。分别测定了分、合流测     

径向反应器流体均布设计的研究(Ⅰ)

本研究在实测动量交换系数和穿孔阻力系数的基础上,研究并提出了径向反应器流体均匀合理的设计方法。本文(Ⅰ)就径向反应器流体均布的设计原则、主流道静压的分布、以及径向流体分布的型式和尺寸的选择等三个方面进行了研究和阐述,文中附有计算示例。     

离心型径向固定床分气流道内局部动量交换系数

针对离心型径向固定床气体流道内变质量流动特点,在一套冷模实验装置上,分别采取Π型和Z型操作模式,测量并分析了两气流道内压力分布,发现分气流道内的压力沿气体轴向流动方向呈增加趋势,集气流道与之相反。根据颗粒床层压降分布不均匀度和采用Ergun方程求得的径向气速轴向分布,发现离心Π型均略优于离心Z型。通过对气流道内微元控制体进行流量和动量衡算,由颗粒床层径向气速轴向分布可依次得到分气和集气流道内气速、局部动量交换系数计算方程。相较于集气流道,分气流道内动量交换系数对压力测量误差的敏感度较小。分气流道中,整体动量系数几乎不随操作模式、气体流量和轴向位置发生变化;而局部动量交换系数仅是流速比u/u0的函数,随流速比增大先降低后保持稳定。根据实验结果,回归得到的分气流道局部动量交换系数计算方程的误差在11%以内,有望为气流道内局部压力计算和结构优化设计提供参考。     

列管式固定床反应器流动与传热研究

本文给出了列管式固定床反应器的环形流道内的压力系数、穿孔阻力系数，平行流和错流形式的反应器管间压力分布以及温度试验结果。综合这些研究结果，可以为大型列管式固定床反应器的设计提供可靠的理论依据。     

∏型径向流动反应器流体力学研究

本文根据流体变质量流动的动量微分方程,提出了Ⅱ型径向流动反应器内流体流动规律的数学模型。该模型为一特殊的二阶微分方程的边值问题:Au'u"+Buu'+Cu~2=O边界条件: y=O,u=1 y=1,u=O模型参数A、B、C决定于反应器分布流道的几何尺寸、侧流穿孔阻力系数和床层空隙率等。将该数学模型应用于径向氨氧化炉操作状况模拟,获得了预期的效果。模拟计算还表明:径向床内流体流动方向和反应器结构尺寸对流体均布有显著影响。所提出的数学模型可用于Ⅱ型径向反应流体力学行为的模拟。     

移动床径向反应器中流体力学行为的研究

比较了直径500mm移动床径向反应器中向心Z型、向心Π型、离心Z型、离心Π型4种气体流动类型.实验表明,离心Π型流动时,气体轴向分布不均匀度小于5%,为最佳气体流动类型.文中还得到了描述主流道中静压分布的动量交换系数K值.     

Experimental Simulation on Chemical-looping Combustion of Cold Model（英文）

The pressure profiles, gas velocities, solid circulation rate, solids flux, residence time distribution of gas and particles in chemical-looping combustion reactors and gas leakage were studied in a cold flow model unit. And these parameters in both air and fuel reactors were measured in the experimental stage. The experimental results show that gas fluidization velocity in the air reactor is 1.8 m/s, gas fluidization velocity in the fuel reactor 0.5 m/s, and the bed materials inventory of the two reactors between 1.2 to 3.15 kg. The first cold flow model results show that the solid circulation rates are sufficient. The appropriate operating conditions are optimized and the summary of final changes is made the on cold model. The proposed design solutions are currently being verified in a cold flow model simulating the actual reactor(hot) system. This paper presents an overview of the research performed on a cold flow model and highlights the current status of the technology.     

Experimental Simulation on Chemical-looping Combustion of Cold Model

The pressure profiles, gas velocities, solid circulation rate, solids flux, residence time distribution of gas and particles in chemical-looping combustion reactors and gas leakage were studied in a cold flow model unit. And these parameters in both air and fuel reactors were measured in the experimental stage. The experimental results show that gas fluidization velocity in the air reactor is 1.8 m/s, gas fluidization velocity in the fuel reactor 0.5 m/s, and the bed materials inventory of the two reactors between 1.2 to 3.15 kg. The first cold flow model results show that the solid circulation rates are sufficient. The appropriate operating conditions are optimized and the summary of final changes is made the on cold model. The proposed design solutions are currently being verified in a cold flow model simulating the actual reactor (hot) system. This paper presents an overview of the research performed on a cold flow model and highlights the current status of the technology.     

径向流固定床反应器的流动特性研究及结构参数的合理选择

径向流固定床反应器的操作状态和反应效果在很大程度上取决于反应器内穿越催化剂床层径向气流沿反应器轴向分布的均匀程度，亦即床层内催化剂负荷的均布程度。本文对此类反应器内的流动特性进行了研究，对立了描述反应器内流动规律的基本运动方程。研究结果表明，径向气流的轴向分布情况与反应器的流动结构型式、反应器内分流流道与合流流道截面积的比值、催化剂床层的阻力系数以及反应器的高径比等参数有关。并提出了如何合理选择反     

Modeling of Radial Flow Reactors of Oxidative Reheat Process for Production of Styrene Monomer

Styrene plays an important role in industrial production plants due to its increasing use in the production of various products. Thus, availability of a simulating program for styrene monomer reactors is of major importance in reducing the problems of a styrene unit. In oxidative reheat technology, styrene monomer is produced from ethylbenzene dehydrogenation in radial flow reactors in the presence of the generated heat from hydrogen oxidation reaction. In this article mass, energy and momentum equations on radial direction are developed for styrene monomer reactors. Required kinetic rates and parameters have been adopted from the literature [1,2]. Then, by means of experimental data from industrial reactors and sequential quadratic programming (SQP) methods, suitable kinetic parameters are obtained. Comparison of simulator prediction data with industrial ones show that the simulation has been achieved adequately.     

Hydraulic design of multitubular reactors with a heat carrier flowing in parallel to the tubes

A mathematical model of the liquid heat carrier flow in the intertubular space of parallel-flow multitubular reactors is presented. The model was verified experimentally by measurements carried out in a model multitubular apparatus of rectangular cross-section.If the design of the distributing plates in industrial reactors is based on this model, uniform heat transfer conditions may be achieved throughout the intertubular space. The uniformity of the coolant flow distribution can be quantified by a velocity uniformity index (VUI) introduced in this paper.     

轴向流固定床内流场的数值模拟与实验验证

The computational fluid dynamics model with porosity and drag coefficient was used to describe fluid flow in an axial flow fixed bed according to the characteristics of fluid flow in the fixed-bed of the reactor. The commercial computational fluid dynamics (CFD) code CFX was used to simulate the flow field in the axial flow fixed bed. The simulation predictions are in good agreement with experimental results of a large cold model. The influence of gas distributor on the flow field in the axial flow fixed bed was studied. A suitable gas distributor was used to attain less than 0.06 kPa radial pressure difference and less than 5.2% radial velocity difference in fixed bed.     

Turbulent Modeling of the Production of Ultra Fine Aluminum Particles: Scale-Up

A convenient way to synthesize aluminum nanoparticles is to evaporate the metal, direct this vapor into a tubular reactor and quench it with a radial flow of cold gas. The supersaturated vapors nucleate and grow into the desired nanoparticles. For small-scale operations, because of the high temperatures and relatively low flow rates involved, the conditions of operation are usually laminar. As the units are scaled up to higher production rates, the flows become transitional or even fully turbulent. This work reports on the use of a Low Reynolds Number (LRN) turbulent model to simulate this system and its scale up for the synthesis of pure aluminum powders. Coagulation was identified as the dominating mechanism in particle growth for the conditions and scales studied. Scale up with dynamic similitude results in increased residence time which significantly changes the particle properties during scale-up. In scale-up with constant residence time, the flow field regime changes from laminar to turbulent. These changes in the flow regime affect the particle characteristics significantly for reactors of small length to diameter ratio (L/D = 6), but are almost insignificant for large length to diameter ratios (L/D = 12). Turbulent reactors showed small changes in the particle characteristics, plus a better percentage of metal vapor recuperated as particles at the end of the reactor.