共查询到16条相似文献,搜索用时 62 毫秒
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选用欧拉-欧拉多相流模型和RNG k-ε湍流模型对不同进料形式鼓泡床反应器进行了三维全尺寸模拟,分析并比较了采用不同形式进料的反应器内气含率和轴向液速的异同。结果表明:不同进料形式的鼓泡床反应器内均形成了循环流动;文丘里喷嘴和多喷嘴的性能优于单喷嘴;环管分布器和排管分布器能提供均匀的气含率分布和大尺度的液相循环流动,性能优于3种喷嘴进料形式。 相似文献
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在直径45 mm的鼓泡床冷态装置中,以煤油作为液相,氮气作为气相,研究了气含率、气泡平均粒径、两相相间滑动速度的变化规律。结果表明:反应器内流体的流动处于气泡聚并控制区,气含率随着两相流速的增加而增加;气泡平均粒径随着气相表观流速的增加而增加,随着液相表观流速的增加而降低。实验发现,在相同的条件下,与较小直径反应器相比,随着反应器直径的增大,气泡聚并作用增强,气含率下降,气泡粒径增大。 相似文献
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唐晓津 《中国炼油与石油化工》2019,21(3):90-93
Xenon was used as gas phase to investigate the hydrodynamic characteristics in a bubble column. It was found that the flow pattern is mainly in the churn-turbulent flow regime by analysing the relationship between the slip velocity and gas holdup. The influences of operating conditions on the gas holdup and Sauter mean diameter were studied. The experimental results show that the Sauter mean diameter decreases with the increase of energy dissipation rate. A new correlation was developed to predict the Sauter mean diameter with an average error less 15%. 相似文献
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采用计算流体力学(CFD)对鼓泡床反应器内气液两相流场进行数值模拟,考察了3种出口边界条件和1种入口边界条件对模拟结果的影响;比较了水-空气体系和重油-氢气体系的流体力学性质。通过Fluent程序将上述模型分别与欧拉双流体模型和RNG k-ε两相流模型进行耦合计算,得到气含率和轴向液速分布,并与冷模实验结果进行对比,得到能准确预测鼓泡床反应器内流型的CFD模型。结果表明:出口边界条件为Degassing时对整体气含率的模拟结果较好,但含有气相空间的压力出口对局部气含率和轴向液速的模拟结果较好,二者的数值结果差异较小。当入口空气体积分数大于0.75时,整体气含率的模拟值与实验值相当,数值模拟时将反应器底部简化成均一进气口可以得到合理的结果。水-空气体系和重油-氢气体系的轴向液速和气含率的变化趋势相同,重油-氢气体系的轴向液速在数值上稍低于水-空气体系,而气含率稍高。采用水-空气体系近似替代重油-氢气体系研究鼓泡床反应器具有借鉴意义。 相似文献
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从工程设计的角度,以影响气液传质主要因素人手,低能耗为目标。应用鼓泡技术对鼓泡反应器的操作条件以及物料工况作了优化。通过计算得到:操作气速为0.10m/s时,可在低压力降下达到理想的气含率以及轴向混合效果:进料气体温度为50℃,液体温度为35℃时,可使反应器无需加热或撤热设备;降低操作压力可以降低鼓泡反应体系动力消耗,以达到降低能耗的目的。 相似文献
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加压浆态鼓泡床中固含率与气含率轴向分布的研究 总被引:1,自引:0,他引:1
在高6.6 m、直径0.3 m的浆态鼓泡塔中,采用动态气体逸出法研究了水-空气-石英砂体系中固含率与气含率的轴向分布。在表观气速0-0.24 m/s、固体质量分数(石英砂在水中的质量分数)0-23%、压力0.1-2.0 MPa范围内,考察了各种因素对固含率和气含率轴向分布的影响。实验结果表明,随着表观气速的增加和固体质量分数的减小,固含率的轴向分布趋于均匀;气含率随压力和表观气速的升高而增加;固体质量分数仅仅影响大气泡气含率和上升速率,而对小气泡气含率和上升速率的影响不大;在固体质量分数大于23%时,压力对气含率轴向分布的影响比较显著。 相似文献
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Two kinds of gases were used to investigate the influence of gas density on the hydrodynamic characteristics ina bubble column. It can be found out that higher gas density leads to smaller bubble diameter and the flow patterns are differentfor the both gases. Energy balance mechanisms are analyzed by considering the gas density difference. Models weredeveloped to predict the average bubble diameter with good accuracy. 相似文献
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采用空气-羧甲基纤维素钠水溶液-固体物料体系,对漩流鼓泡塔反应器的气液传质性能进行了研究。在常温(20℃)、常压、非牛顿流体条件下,测试了反应器的平均气含率,漩流鼓泡塔反应器分别装有直板型和弯板型(3种直径)气体喷流器。由实验数据回归得出平均气含率与流体性能、空塔气速之间的关联式。与直流鼓泡塔反应器相比,漩流鼓泡塔反应器的平均气含率较高,其中CBⅡ型漩流鼓泡塔反应器比直流鼓泡塔反应器的平均气含率高20%左右。 相似文献
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The equilibrium solubilities,volumetric gas-liquid mass transfer coefficients kLa of H_2 and CO were measured as functions of temperature(298―513 K),pressure(1―3 MPa),superficial gas velocity(0.5―3 cm/s) and solid volume fraction(5%―25%) in liquid paraffin/iron-based catalyst slurry bubble column reactor.The volumetric mass transfer coefficients kLa were obtained by measuring the dissolution rate of H_2 and CO.The influences of the operation conditions,such as pressure,temperature,superficial gas velocity and catalyst concentration on kLa,were investigated.Two empirical correlations were proposed to predict kLa values of H_2 and CO in liquid paraffin/solid particles slurry bubble column reactor.The results showed that the equilibrium solubilities of H-2 and CO increased with an increasing temperature and pressure,and the solubility of CO was greater than that for H_2.It was found that the equilibrium solubility can be expressed by Henry's law.The volumetric mass transfer coefficients of H_2 and CO were of the same order of magnitude,and increased with the increase of pressure,temperature and superficial gas velocity.The presence of solid particles decreased kLa values of both H_2 and CO. 相似文献
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DynamicCharacteristicsofBubbleDistributionZoneinGasLiquidReactorsYuanNaiju,DuJianxin,HuHua,LiuZheng,DingFuxin(DepartmentofCh... 相似文献
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