高固含率下沸腾床反应器的流体力学行为及关键模型参数的研究

发布时间：2018-04-24 18:51

本文选题：沸腾床 + 气含率　；参考：《华东理工大学》2015年硕士论文

【摘要】：沸腾床反应器(Ebullated-Bed Reactor)因其结构简单、传热性能好、温度易控制、操作费用低等优点,而广泛应用于石油化工、生物化工、废水处理和煤的液化等领域,对其进行深入的研究有着重要的学术和工业应用价值。本论文结合工业渣油加氢反应器设计和工艺操作条件,建立了直径0.3 m、高7.2 m的沸腾床反应器大型冷模装置。采用空气-水-球形氧化铝颗粒体系模拟工业反应器内的气-液-固三相流体力学行为,测量了总气含率、大小气泡上升速度,以及气液体积传质系数、液体和固体的循环速度、轴向固体浓度分布等关键模型参数,讨论了表观气速(0.025～0.232m.s-1)、表观液速(0～0.0219 m.s-1)、液体粘度(1.2～210.4 mPa·s)和固相体积分率(0-60vo1%)对这些关键流体力学参数的影响。实验结果表明：随着表观气速的增大,塔内总气含率、气泡上升速度、气液体积传质系数、固体的循环速度均会增大；表观液速对这些流体力学行为的影响比较小；增大液体粘度,会降低体系内小气泡分率,从而降低总气含率,同时也会降低气泡上升速度,使轴向固体浓度的分布趋于均一化；固相体积分率的影响作用与粘度保持一致,可以将液固体系拟均相化作为浆态体系处理。运用气含率的漂移通量模型,将本文实验数据与模型参数拟合,结合粘度、固含率对体系的影响,得出高固含率(60vo1%)下的气含率以及气泡上升速度的经验关联式；将一维沉降-扩散模型参数重新修正后,得到了适用范围更广泛的轴向固体浓度分布模型。
[Abstract]:The fluidized bed reactor (Ebullated-Bed Reactor) is widely used in petrochemical, biochemical, wastewater treatment and coal liquefaction because of its simple structure, good heat transfer performance, easy temperature control and low operating cost. The in-depth study has important academic and industrial application value. Based on the design of industrial residue hydrogenation reactor and operation conditions, a large scale cold model unit of fluidized bed reactor with diameter of 0.3 m and high of 7.2 m was established in this paper. The gas-liquid-solid three-phase hydrodynamic behavior in industrial reactor was simulated by air-water-spherical alumina particle system. The total gas holdup, bubble rising velocity and gas-liquid volume mass transfer coefficient were measured. The key model parameters, such as the circulation velocity of liquid and solid, the distribution of axial solid concentration, and so on, are discussed. The effects of apparent gas velocity of 0.025 ~ 0.232 m 路s ~ (-1), apparent liquid velocity of 0 ~ 0.0219 m 路s ~ (-1), liquid viscosity of 1.2 ~ 210.4 mPa ~ (4) and solid volume fraction of 0-60vo1) on these key hydrodynamic parameters are discussed. The experimental results show that with the increase of the apparent gas velocity, the total gas holdup, bubble rising velocity, gas-liquid volume mass transfer coefficient, and the circulation velocity of solid will all increase, and the apparent liquid velocity has little effect on these hydrodynamic behaviors. Increasing the viscosity of liquid will decrease the fraction of small bubbles in the system, thus reducing the total gas holdup, at the same time, it will also reduce the rising velocity of bubbles and make the distribution of axial solid concentration tend to homogenize, and the effect of volume fraction of solid phase will be consistent with that of viscosity. The liquid-solid system can be treated as slurry system. By using the drift flux model of gas holdup and fitting the experimental data with the model parameters, combining the effects of viscosity and solid holdup on the system, the empirical correlations of gas holdup and bubble rising velocity under high solid holdup are obtained. After modifying the parameters of one-dimensional sedimentation diffusion model, a more widely applicable axial solid concentration distribution model is obtained.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ051.11

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