共查询到19条相似文献,搜索用时 796 毫秒
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利用由静态混合器、喷嘴和分气盒组成的新型布气装置在搅拌釜式反应器中诱导生成泰勒流,对反应器流动特性及反应特性进行了实验研究。结果表明,与常规搅拌釜式反应器相比,泰勒流反应器内物料流动更加接近于平推流流型,泰勒流的生成在反应器内构建出局部平推流区域,降低了物料返混程度。反应器反应性能因流动特性改变而得以增强,相同实验条件下,在泰勒流反应器中进行的蔗糖水解反应转化率比在常规搅拌釜式反应器中高出26.7%。在一定操作范围内,局部平推流区域和反应转化率均随搅拌转速或进气量的增加而增大。泰勒流反应器可简化为平推流区和全混流区并联的流动模型,推导出了反应转化率与平推流区域占反应器总体积比率之间的关联关系。 相似文献
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多相流反应器广泛应用于化工、冶金、能源及医药等过程工业,其内部具有非稳态、非线性、非平衡的自然属性,因而对多相流检测技术提出了挑战。准确检测并理解多相流体力学特性、进而揭示并掌握多相流反应器设计及放大规律,一直是当今过程工程领域的前沿课题之一。磁共振成像(MRI)作为一种非侵入式、多维瞬态全流场先进检测手段,可获得准确详尽的多维流场信息,包括颗粒浓度与速度(脉动)场、流型识别、气泡尾涡、颗粒聚团等多尺度流场参数及介尺度流动结构。此外,MRI在数值模型验证与改进方面也具有良好的应用前景。概述了MRI技术原理,重点论述了MRI近年来在气固及气液反应器中的研究现状,展望了MRI在多相流反应器中有待拓展的方向。 相似文献
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为了实现工业化应用,微反应器的并行放大已成为最有效的放大策略之一。在微反应器的放大过程中,相分布规律的研究是非常重要的。采用高速摄像仪研究了梳状并行微反应器的支通道间距和流量对液液两相分布的影响。当连续相和分散相流量Qc及Qd都较小时,不同支通道间距的微反应器内前方支通道的分散相含率较低,后方支通道的分散相含率较高,同时液滴长度的均匀性较差。随着Qc与Qd的增大,三种不同构型微反应器内分散相的体积相含率的数值分布逐渐趋于集中。在较高的两相流量下,支通道内液滴长度的均匀性显著提高,其变异系数小于0.15。在实验范围内,支通道间距S = 0.6 mm的微反应器中液滴尺寸均匀分布的操作范围最大。 相似文献
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气升式环流反应器是一种结构简单,传质、传热效率高的多相反应器,反应器性能受物性参数和结构参数的影响,由于两相和三相流的复杂性,使得其在工业化设计放大和应用过程中存在困难。论述了气升式环流反应器内相间作用力类别和计算模型,对应用于气升式环流反应器模拟计算的简化模型、两相流模型和k-ε湍流模型进行总结,在分析现阶段气液两相流理论的基础上,明确反应器内不同流动形态下相间作用力、气泡的分散机理、气泡对湍流的影响、流动模拟模型的选取标准,能有效提高气升式环流反应器模拟的准确性及模型的普适性,为反应器的设计放大及传质模拟计算提供更加可靠的理论依据。 相似文献
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微气泡具有气液接触面积大、气体溶解速率快、上升速度慢和水中停留时间长等理化特征,非常适合于高气液传质效率需求的生物发酵过程。本文介绍了能够耦合生物反应器的几种微气泡发生装置,分别为微气泡分散器、微孔膜、流体振荡器耦合微孔膜和微气泡曝气搅拌桨;并简述了微气泡发生装置耦合搅拌式生物反应器、气升式生物反应器和生物膜反应器在生物反应过程的应用进展;最后回顾了二氧化碳微气泡在生物反应器的应用研究进展。指出微气泡耦合生物反应器的研究仍处于起步阶段,在放大规律和能耗方面仍处于研究空白。微气泡耦合生物反应器的发展对工业生物技术、石油化工、污水处理和资源再利用等的发展具有重要的意义。 相似文献
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随着煤炭间接液化技术在百万吨级商业示范装置上的成功应用,作为其核心设备的费托合成浆态床反应器,涉及气液固三相湍流流动、传热传质及反应,其随反应器直径放大及内构件结构布局的变化而发生改变,进而影响反应器性能的多个复杂过程,导致在反应器设计、放大及操作优化上面临巨大挑战,科研及工业界仍然持续重视。本综述分析了影响浆态床反应器流体力学性能的主要因素,对浆态床反应器的流型、气含率、气泡行为、传热等研究进行了总结。介绍了浆态床反应器核心内构件的结构特点及发展状况,回顾了浆态床在费托合成反应过程中的工业应用历程,并展望了费托合成浆态床的研究趋势。 相似文献
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Investigation of mixing in a rotor shape modified Taylor-vortex reactor by the means of a chemical test reaction 总被引:1,自引:0,他引:1
Oliver Richter 《Chemical engineering science》2009,64(10):2384-2391
The macro- and micromixing properties of a continuous flow Taylor-vortex reactor can be optimised by changing the conventional cylindrical rotor geometry into a novel ribbed one. A chemical test reaction, the micromixing-sensitive alkaline saponification of ethylacetate with separately fed reactants, was used to probe the mixing performance down to the molecular level. Experiments were performed in a continuous flow Taylor-vortex reactor equipped either with a conventional cylindrical rotor or with a novel ribbed rotor in a wide hydrodynamic range of 150<Ta<8000 and 0.8<Re<2.0.Through increase in the reaction temperature and the feed concentrations, the relaxation times of this reaction were reduced from 680 to 19 s and compared to micromixing times by monitoring the reactor conversion. The results show that a TVR with conventional rotor achieves intense micromixing at high rotor speed, but behaves like a CSTR. In contrast, a device with ribbed rotor shows macromixing features close to those of a plug flow reactor (PFR) in a wide range of rotor speeds; however, segregation of the two feeds could only be dissipated at slow reaction rates, i.e. relaxation times larger than 64 s. 相似文献
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Marco Meeuwse John van der Schaaf Jaap C. Schouten 《American Institute of Chemical Engineers》2012,58(1):247-255
The scale up of a rotor‐stator spinning disc reactor by stacking single stage rotor‐stator units in series is demonstrated. The gas‐liquid mass transfer per stage is equal to the mass transfer in a single stage spinning disc reactor. The pressure drop per stage increases with increasing rotational disc speed and liquid flow rate. The pressure drop is more than a factor 2 higher for gas‐liquid flow than for liquid flow only, and is up to 0.64 bar at 459 rad s?1. The high mass and heat transfer coefficients in the (multistage) rotor‐stator spinning disc reactor make it especially suitable for reactions with dangerous reactants, highly exothermic reactions and reactions where selectivity issues can be solved by high mass transfer rates. Additionally, the multistage rotor‐stator spinning disc reactor mimics plug flow behavior, which is beneficial for most processes. © 2011 American Institute of Chemical Engineers AIChE J, 2012 相似文献
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以木质纤维素生产燃料乙醇为背景,在考察玉米秸秆同步糖化与发酵反应特征基础上,给出了合适的反应器构型:螺带型搅拌槽;直径0.2~0.8m,高径比1~2,转速20~120r/min,着重从冷模实验对搅拌槽性能进行了考察,为反应器放大提供必要的基础。实验结果发现,层流流动条件下,随流体剪切稀化性质增强,搅拌功率(Np)显著降低,而无因次混合时间(Ntm)则变化不大;给出适用于强剪切稀化流体的Metzner常数Ks关联式,且Ks与搅拌槽直径无关;对于几何相似的螺带桨,随着搅拌槽直径增大,若保持相同的单位体积功率,Ntm是相同的,这为我们提供了一个螺带型搅拌槽的放大准则;搅拌槽功耗及Ntm随着搅拌槽高径比的增大而增大;最后采用数值计算方法对搅拌槽内分散混合效率进行了考察,发现,根据混合效率的不同,可将螺带型搅拌槽分成几个不同的区域,搅拌槽内体积平均分散混合效率接近于0.5(简单剪切流)。纤维素酶水解反应器的放大,小试给出关键参数(单位体积生产能力),冷模实验提供混合性能、几何结构设计基础,经验判据与CFD相结合,关注基本流型的尺寸效应,兼顾单位体积功率及最大剪切速率。 相似文献
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FCC反应过程的CFD模拟进展 总被引:1,自引:1,他引:0
流化催化裂化(fluid catalytic cracking,FCC)工艺是石油炼制中的重要转化工艺,用于生产汽油、柴油、轻质烯烃等重要化工原料。FCC反应过程的CFD模拟有助于理解FCC反应器中流动和反应行为,辅助设计和优化FCC工艺设备,最终指导工业生产和实现虚拟调控和放大。从与FCC反应模拟相关的多相流动模型、反应动力学模型以及流动与反应之间耦合等方面做了回顾和总结。在流动与反应耦合研究方面,从湍流模型的使用、流动结构的影响、精细化模型的发展以及原油汽化模型的重要性这4个角度做了分析比较及总结。基于已有的研究工作,认为虽然很多研究表明CFD模拟能较好地揭示工业FCC提升管反应器内的流动和反应行为,但缺乏采用同一方法实现从小试到工业反应器模拟放大的实例,从侧面反映了当前的FCC理论模型和模拟技术还远未达到可以代替实验的水平。展望未来的FCC反应模拟,建议从模型精细度和计算效率上加强研发,并在此两方面寻求平衡,最终实现虚拟调控。 相似文献
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Lukas Bittorf Felix Reichmann Mira Schmalenberg Sebastian Soboll Norbert Kockmann 《化学工程与技术》2019,42(10):1985-1995
Process development and small‐scale production gets more and more important in fine chemistry and pharmaceutical production. An equipment toolbox assists process synthesis presented in this contribution. A microfluidic calorimeter can measure kinetic and thermodynamic reaction data with commercial plate reactors. A tubular reactor coiled with 90° bends allows for long residence time with low axial dispersion, also known as coiled flow inverter (CFI). A similar setup is used for continuous‐flow cooling crystallization. Small‐scale columns with rotating internals are employed for distillation and liquid‐liquid extraction. Main emphasis will be put on automation and scale‐up in future steps. 相似文献
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The comparative behaviors of a micro-scale fixed bed multiphase reactor in up flow and down flow modes of operation were studied for hydrodesulfurization of atmospheric gas oil over a commercial catalyst. The experiments for the two modes of operation were conducted for a wide range of diluent size and other process variables such as liquid hourly space velocity and hydrogen/gas oil ratio. The results showed that the down flow mode of operation using 0.19 mm size of diluent could be used for generating reliable and meaningful data. On the other hand, the use of up flow mode of operation is restricted only for higher space velocities even while using 0.19 mm size of diluent. The results also indicated that the performance of the up flow mode of operation was poor at higher hydrogen/gas oil ratio. This change in performance is pronounced when higher size of diluent was used with the catalyst. In contrary, the hydrogen/gas oil ratio had minimum effect on the performance of the reactor for down flow mode of operation. 相似文献
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Multiple Analysis in a Reactive Distillation Column for the Synthesis of tert‐Amyl Methyl Ether 下载免费PDF全文
tert‐Amyl methyl ether (TAME) is produced via reactive distillation. A simulation is set up and controlled on Aspen HYSYS v 8.0 for generating the highest purity of TAME. This simulation includes a plug‐flow reactor and a reactive distillation column. Emphasis was put on finding the optimal operating conditions of the reactive distillation column in order to get the maximum purity of TAME. The operational parameters were reflux ratio, number of reactive stages in the distillation column, and condenser pressure. The results indicated the optimal reflux ratio and condenser pressure which could be adapted to industrial scale. 相似文献