共查询到19条相似文献,搜索用时 171 毫秒
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采用蒽醌加氢反应为探针,研究了脉冲流操作、周期性填充和周期性操作3种非定态操作方式对TBR反应器性能的影响.结果表明,在脉冲流区操作TBR的催化剂质量空时收率比滴流区操作提高50%以上,表观动力学研究证实脉冲流区操作TBR蒽醌加氢反应的表观活化能比滴流区操作更接近本征活化能;催化剂与惰性颗粒的交替填充周期性地强化了气液相间传质速率,提高催化剂质量空时收率40%以上;反应器的周期性操作,同时强化气液和液固相间传质速率,改善反应器内的流体力学状况,从而提高反应的空时收率和选择性10%以上. 相似文献
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引 言钛硅催化剂 (TS - 1)上的丙烯与H2 O2 环氧化过程是环氧丙烷 (PO)洁净生产的发展方向[1,2 ] ,但对于环氧化反应器的研究尚很不完备 .该反应是一个强放热的气液固三相反应 ,要实现该反应过程的连续化 ,可以采用搅拌釜式反应器或固定床反应器(滴流床反应器 ) .搅拌釜式反应器主要用于催化剂性能评价 ,由于搅拌釜内物料返混严重 ,反应器体积效率较低 ;固定床反应器是由美国ARCO公司的Jubin[3] 等发明的 ,实际上为多段气液呈并流向下的滴流床反应器 ,该反应器结构复杂 ,操作压力较大 (在 1.2 5MPa以上 ) ,且为了便于控… 相似文献
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小颗粒滴流床反应器的流体力学研究 总被引:2,自引:1,他引:2
在内径为0.047m,床层高0.7m的滴流床反应器内,采用空气-水-玻璃珠(1.8,3.18mm)体系,在常温、常压下进行实验。气、液流速分别在0.054-0.23kg/(m^2s)和3.20-14.73kg/(m^2s)内,用电导信号脉动法、压降波动法结合目测法测定了滴流床的流动状态及其变化,实验结果可用于确定不同操作条件下的流动状态。本研究还分别是用差计、示踪剂法和体积法对滴流床的压降,总持流 相似文献
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唐涌濂 《化学反应工程与工艺》1989,5(4):61-70
滴流床中气液流速较高时会产生脉冲流。脉冲特性可表示为:脉冲频率、脉冲速度、脉冲持液与脉冲间持液。这些参数可用气液流速、填料特性及气液物性来度量。在宏观物料衡算基础上推得脉冲速度的模型。脉冲持液就是反应器的动持液;脉冲持液与脉冲间持液之比近于1.5。发现脉冲频率完全受表观液速与临界液速的差值所控制。获得了三个关联式,涉及不同系统,也包含文献数据。 相似文献
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滴流床反应器的研究现状和展望 总被引:2,自引:0,他引:2
近十几年来。滴流床反应器越来越受到人们的重视。本文从滴流床反应器的流体力学特性、相际传质和数学模型等方面,较全面地回顾了国内外的研究状况。由于气液固三相的存在,反应器内流动、混合、传质等过程十分复杂,大多数工作是利用实验结果得到有关模型和参数的经验关联式,理论工作相对来说比较薄弱。必须引入更先进的理论和方法,使滴流床反应器的研究超越传统的经验关联式水平,提高到更加科学的高度。 相似文献
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滴流床反应器是一种典型的气液固三相反应器,广泛应用于化学与石油加工工程。相间、相内传质以及催化剂表面相互作用、催化剂的有效润湿率、反应器流体力学、反应器模型等这些因素都影响着滴流床的反应性能。文章采用的滴流床反应器即是在固体催化颗粒床层内气液两相反应物自上而下流动(沿重力方向)的一类反应器。苯二酚是重要的精细化工中间体,用途非常广泛。我们采用CFD模拟了苯酚氧化生成苯二酚的反应。用网格划分粗细的影响及床层催化剂空隙率对流场的影响,计算为三维模拟计算。模拟了局部气含率、持液量,压力降,轴向速度分布及其径向分布速度等数据,探究了模拟方法,为进一步研究提供了参考依据。 相似文献
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合成1,4—丁二醇开发技术中的工艺与工程 总被引:1,自引:0,他引:1
合成1,4-丁二醇的大规模工业生产是在国内外同时采用滴流床、浆态床和三相悬浮床三种反应器仅有的反应工艺,对这一反应工艺所用不同反应器的开发方法,包括催化剂制备及考评,各种专用冷模试验和专用反应器的热模试验及动力学测定。应用数学模拟分析和实验相结合,从小试、中试到工业试验,可为大型装置设计提供依据。本文总结了气、液、固三相反应器的基础研究和工业实践相结合的经验、催化剂和反应器工程协调的评价,以及催化剂的制备技术。 相似文献
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Bora Aydin 《Chemical engineering science》2008,63(6):1510-1522
The effects of temperature and pressure on the structure of the trickle-to-pulse flow regime transition in slow-mode cyclic operation in trickle-bed reactors were reported. The relationship between liquid holdup and liquid velocities at the trickle-to-pulse flow transition in cyclic operation, the shock wave behavior as a function of bed depth, as well as the pulsing flow regime properties were investigated for Newtonian (air-water) and non-Newtonian (air-0.25% carboxymethylcellulose (CMC)) liquids. At a given temperature, the breakthrough, plateau and decay times of the shock wave were found to decrease with bed depth. The pulse velocity and pulse frequency for pulsing flow regime both in cyclic operation and in natural pulsing (constant-throughput operation) were observed to increase with temperature. However, increasing the reactor pressure led to increased pulse frequency and decreased pulse velocity. Analysis of the transition liquid holdups for natural pulse flow and cyclic operation revealed that the liquid holdup decreased with temperature and pressure. The transition liquid holdups and superficial liquid pulse velocities in symmetric peak-base cyclic operation surpassed those in constant-throughput operation for given temperature, pressure and gas velocity, giving rise to wider trickle flow regime area in cyclic operation. The behavior of both Newtonian and power-law non-Newtonian fluids was similar regarding the effect of temperature, pressure and gas velocity. 相似文献
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通过采用电容层析成像仪测定了不同气速、不同液速、不同操作方式以及不同床层位置的持液量滞后曲线,发现影响持液量滞后的最大因素是液体流速。在实验的基础上,分析了不同操作状态下产生滞后现象的原因,并提出了采用持液量滞后曲线终点来判断脉冲点的关联式:Re^*LReG^*0.42042=800。 相似文献
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Experiments and simulations were conducted for bubble columns with diameter of 0.2 m(180 mm i.d.), 0.5 m(476 mm i.d.) and 0.8 m(760 mm i.d.) at high superficial gas velocities(0.12–0.62 m·s-1) and high solid concentrations(0–30 vol%). Radial profiles of time-averaged gas holdup, axial liquid velocity, and turbulent kinetic energy were measured by using in-house developed conductivity probes and Pavlov tubes. Effects of column diameter, superficial gas velocity, and solid concentration were investigated in a wide range of operating conditions. Experimental results indicated that the average gas holdup remarkably increases with superficial gas velocity, and the radial profiles of investigated flow properties become steeper at high superficial gas velocities. The axial liquid velocities significantly increase with the growth of the column size, whereas the gas holdup was slightly affected. The presence of solid in bubble columns would inhibit the breakage of bubbles, which results in an increase in bubble rise velocity and a decrease in gas holdup, but time-averaged axial liquid velocities remain almost the same as that of the hollow column. Furthermore, a 2-D axisymmetric k–ε model was used to simulate heterogeneous bubbly flow using commercial code FLUENT 6.2. The lateral lift force and the turbulent diffusion force were introduced for the determination of gas holdup profiles and the effects of solid concentration were considered as the variation of average bubble diameter in the model. Results predicted by the CFD simulation showed good agreement with experimental data. 相似文献
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对直径280mm、扩大直径500mm、外循环管直径65mm、总高2900mm的外循环型鼓泡式反应器,在气体空塔线速Ug为0.04-0.55m/s时,用静压差法和脉冲示踪法测定了不同部位的气含率Eg,Epg和循环液速率u1,并获得了它们的关联式:对反应段,Eg=0.4556U^0.3198g〔Ug/(Ug+U1)〕^0.7396;对反应器扩大段,Eug=0.9389U^0.4431ug;对循环管,E 相似文献
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Recovery of carbon monoxide from flue gases by selective absorption of carbon monoxide in an imidazolium chlorocuprate(I) ionic liquid is considered in this work as an alternative to the use of molecular volatile solvents such as aromatic hydrocarbons. The present work evaluates the CO mass transfer rates from the gas phase to the ionic liquid solutions in the absence of chemical reaction. To that end, carbon dioxide was employed as an inert model gas and absorption experiments were performed to assess the influence of different process variables in a batch reactor with flat gas–liquid interface. The experimental mass transfer coefficients showed significant var-iation with temperature, (3.4–10.9) × 10-7 m·s-1 between 293 and 313 K; stirring speed, (10.2–33.1) × 10-7 m·s-1 between 100 and 300 r·min-1;and concentration of copper(I), (6.6–10.2) × 10-7 m·s-1 between 0.25 and 2 mol·L-1. In addition, the mass transfer coefficients were eventually found to follow a poten-tial proportionality of the type kL∝μ-0.5 and the dimensionless correlation that makes the estimation of the mass transfer coefficients possible in the studied range of process variables was obtained:Sh=10-2.64·Re1.07·Sc0.75. These results constitute the first step in the kinetic analysis of the reaction between CO and imidazolium chlorocuprate(I) ionic liquid that determines the design of the separation units. 相似文献