浆态床鼓泡反应器中气含率的分布

为了解浆态床鼓泡反应器中气含率的分布规律,在浆态床鼓泡反应器冷模试验装置中,以空气-液体石蜡-氧化铝微球为试验介质对装置内部的气含率进行研究。利用压差法研究了表观气速、浆液固含量等操作条件对反应器床层总体气含率的影响,利用光纤探针法研究了浆态床反应器不同操作条件对局部气含率的影响,总结了反应器内部气含率的分布规律,并由此对工业浆态床鼓泡反应器的设计进行了研究。结果表明:浆态床反应器的总体气含率随表观气速的增大而增大,固体细颗粒的加入能适当降低总体气含率;在反应器底部,分布器对气体的均布作用明显,但表观气速的增大能够弱化分布器的作用;在反应器的中上部气含率不受分布器的影响,沿反应器径向呈现"中间高,边缘低"的分布趋势;在工业费托浆态床中,表观气速不宜低于0.12 m/s,内过滤系统适宜设置于反应器中上部靠近器壁的位置。     

加压大型气液鼓泡床中气含率的实验和关联

对内径0.3 m、高6.6 m的加压鼓泡床中的气含率进行了系统研究，得出了表面张力、粘度、压力等对气含率的影响规律；结果表明，在实验范围内，鼓泡床中的气含率随表面张力和粘度的升高而降低，随压力的升高而升高；并用气泡聚并的能量理论作了定性的解释. 根据542组实验数据得出了气含率的关联式.     

变径鼓泡浆液反应器的气含率特性

本文研究了变径鼓泡浆液反应器的平均气含率特性,考察了气体速度、静液床高、固体颗粒浓度以及颗粒直径的影响,并提出了变径鼓泡浆液反应器平均气含率的计算方法。     

加压大型鼓泡床反应器内大小气泡气含率研究

在内径0.3m、高6.6m的加压鼓泡床反应器内采用床层塌落技术测量床层内的大小气泡气含率实验。由于大小气泡上升速度不同,床层塌落曲线存在一水平段,在此基础上,详细考察了表面张力、粘度、系统压力、表观气速对大小气泡气含率的影响,得出大气泡气含率随粘度和表面张力升高而升高,随压力升高而降低;小气泡气含率随粘度和表面张力升高而降低,随压力升高而升高;并根据质量守恒定理,进行了解释。     

鼓泡塔中气含率的研究

在φ100×5mm的鼓泡塔中,用空气-稀醇溶液和空气-稀酸溶液研究了包括分子中碳原子数和羟基、羧基在内的诸因素对气含率的影响。得到了气含率ε_G关联式,用于单元醇(或酸)、多元醇(或酸)的气含率计算。     

气液逆流鼓泡塔中的气含率与液速分布和数值模拟

分别采用线－线电导探针和背靠背式皮托和测定了气液逆流鼓泡塔中局部气含率和液体轴向速度的径向和轴向分布,讨论了操作条件对气含率与液体轴向速度分布的影响,利用双流体模型对塔内两相湍流流动进行了数值模拟。     

热态下鼓泡浆液反应器的气含率研究

本文在热态条件下，研究了鼓泡浆液反应器的气含率、反应器直径为0.098m，物系组成为氮气－液体石腊－石英砂。考察了气速、压力、温度、静床高及固体引入等因素对气含率的影响。对于53μm粒子的三相浆态体系，气含率与表观气速关系式为εG=0.053uG^1.2。     

外循环型鼓泡式反应器气含率及循环液速率

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     

锥形鼓泡床内气含率特性的研究

本文分析了锥形鼓泡床内流型过渡、平均气含率及气含率轴向分布特性，考察了入口气体速度、静止液体（或淤浆）高度及淤浆浓度的影响，比较了与圆柱床的差异，结果表明对于鼓泡床内气体体积收缩的反应，用锥形床的冷态试验可以较精确地模拟其实际结果。     

Batch Drying Kinetics in a Two-Zone Bubbling Fluidized Bed

This article deals with investigation and modeling of batch drying process of solids in fluidized bed apparatus. There has been used model of fluidized bed drying, which consists two zones: emulsion zone and bubbling zone with taking into consideration the presence of solid particles in the bubbles. The results of theoretical expectations that arise from simulation calculations have been verified with experimental data obtained with the use of fluidized bed dryer 0.225 m in diameter. A drying process of silica gel, sand, and ammonium sulfate has been tested. To verify the model, the concept of a generalized drying curve has also been employed.     

微孔膜气体分布器对气液传质的影响

本文开发了一种新型微孔膜气体分布器,并对使用该分布器时鼓泡塔反应器内气液传质性能进行了研究。实验结果表明,使用这种新型膜气体分布器可以得到细小均匀的气泡,较大幅度地增大了气液传质比表面积,从而大大强化了反应器的传质能力。     

Solids Holdup of High Flux Circulating Fluidized Bed at Elevated Pressure

Experimental studies on the solids holdup of a high‐flux circulating fluidized bed (HFCFB) at an operating pressure up to 0.5 MPa were carried out. The effects of operating pressure, solids mass flux and superficial gas velocity on the solids holdup distribution were systematically tested. It was found that the solids holdup at elevated pressure increases with increasing solids mass flux but decreases with increasing superficial gas velocity, which is similar to the trends at atmospheric condition. As a result, the condition of a high‐density circulating fluidized bed (HDCFB), i.e., solids holdup in everywhere of the riser is larger than 10 %) is easier to be achieved at elevated pressure than in a HDCFB operated at atmospheric pressure. In the current work, the condition of a full HDCFB with Geldart group B particles has been achieved successfully at 0.5 MPa.     

Studies of Gas Holdup in Bubble Column Reactors

Gas holdup in bubble columns has been investigated over a wide range of operational and geometrical parameters. A criterion has been developed for the prediction of the transitional velocity from the homogeneous to heterogeneous flow regime. Correlations for gas holdup in both regimes are developed and verified against experimental data.     

Gas Holdup in Circulating Bubble Columns with Pseudoplastic Liquids

The contributions of pressure drop due to wall frictional losses to the total gas holdup of two‐phase viscous non‐Newtonian systems were experimentally investigated using a 150 dm³ circulating bubble column. The column had a downcomer‐to‐riser cross‐sectional area ratio of 0.54 and a dispersion height of 2.5 m. Aqueous solutions of xanthan gum and carboxymethyl cellulose were used to simulate a wide range of rheological properties. The average wall shear stress was estimated from Al‐Masry's (1999) correlation for the average wall shear rate in external loop airlift reactors. Pressure drop due to wall shear stress was found significantly contributed by 10–70 % to the total gas holdup. This contribution has always been ignored in the data presented in the literature due to the absence of reliable and simple correlations for the average shear rate and shear stress. Corrections to gas holdup were found necessary for non‐Newtonian solutions with concentrations of ≥ 0.5 wt/wt.‐%.     

管式布风装置对流化床焚烧炉内流化特性的影响

数值模拟了管式布风装置对流化床内气体和颗粒流动特性的影响,获得了床内气体和颗粒瞬时和时均速度及颗粒体积份额分布. 计算结果表明,床内颗粒宏观流动呈现床中心区域为上升流动、壁面区域为下降流动的内循环流动. 分析了风管小孔风速和颗粒直径对床内流化的影响. 计算结果表明,保证床内颗粒和气体良好流化和混合特性的最佳布风管相对距离应在1.5~1.75之间.     

固液分布器中主分布器的实验研究

在不同结构形式的主分布器条件下，研究了表观液速对换热管中固含率、下管箱内床层高度、静压降及平均固含率的影响。利用体积容积法测量了换热管束中的固含率、刻度尺测量了下管箱中的床层高度、U形管测量了下管箱的静压降，并运用差压法测量了下管箱中平均固含率。采用不均匀度函数衡量了不同结构条件下管束间固含率的不均匀程度。实验结果表明：在换热管下方增加优化后的主分布器可以均匀分布固液两相；主分布器直径变化时对下管箱内流动特性的影响大于主分布器轴向位置改变时的影响。     

中心气升式三相强化环流反应器内气含率分布的理论分析

针对一种新型的中心气升式三相强化环流反应器进行了详细的理论分析,根据能量平衡分别推导出了间歇操作和连续操作模式下拟均相流体的环流速度模型,并根据试验数据确定了间歇和连续两种操作模式下相应的模型参数,通过模型计算发现环流速度随内环表观气速的增加而增加,外循环液体量的加入会显著增加环流速度。根据漂流通量模型推导出了环流反应器内环平均气含率模型,发现内环平均气含率随内环表观气速的增加而增加,其变化趋势基本可分为;气泡分散区、过渡区和气泡聚并区三个区域。给出了内环、外环平均气含率的线性关系式,发现在试验范围内外循环液体量的改变基本不对内外环平均气含率的关系产生影响。     

液-固流化床中滤料流场及固含率分布

用PV4A测速仪和CFD数值模拟的方法对液-固流化床内滤料(固体颗粒)的流动行为进行了研究,得出了流化床内滤料的流场分布状况.试验结果表明:流化床中铜锌合金(KDF)滤料的运动速度和固含率随流化床高度的增加分别呈现出先上升后下降的趋势;而沿径向从中心至管壁则呈下降趋势.模拟结果显示的固相运动速度和体积分率的轴径向分布趋势与试验测定结果基本吻合.