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。     

鼓泡塔中无机盐水溶液-空气系统平均气含率的研究

在φ150×5毫米的鼓泡塔中,对无机盐类溶液-空气系统的平均气含率进行了实验研究,考察了氯化钙、硫酸镁、碳酸钠、氯化锌、氯化钠、硫酸钠及其混合溶液离子强度和物性参数对气含率影响的综合效应,并取得了相应的平均气含率计算关联式ε=0.541·(1.251+0.0245 I-0.0018 I~2)ρ~(-0.409)·σ~(-0.516)·μ~(-0.267)·u~(0.576)     

鼓泡塔中气含率的温度和电解质效应

在直径0.10m、高1.05m 的鼓泡塔中,对空气-水、乙醇、5%NaCl(aq)、5%KCl(aq)、5%CaCl_2(aq)、5%Na_2SO_4(aq)、2.34%MgCl_2(aq)等物系气含率的温度效应和电解质效应进行了实验研究。通过引入((P+Ps)/P)数群很好地关联了气含率的温度效应,找出了气含率的电解质校正因子与液相离子强度的关系。     

非牛顿型浆液鼓泡塔内气含率轴向分布实验研究

通过实验研究，得到了非牛顿型浆液鼓泡塔内压力的轴向分布关联式，进而得到了塔内气含率的轴向分布式。为进一步研究非牛顿型浆液鼓泡塔流体力学行为打下基础。     

气—液鼓泡塔中流动域和气含率的分布

利用压力传感器测定了气、液两相鼓泡塔内不同轴、径向位置上压强的脉动信号,分析了压强的脉动特征,计算了各种操作条件下塔内不同轴向位置截面上的平均气含率,发现在不同操作条件下,塔内可能出现不同的流动域分布,即全塔均匀鼓泡域、全塔过渡域、全塔湍动鼓泡域以及均匀鼓泡域,过渡域和湍动鼓泡域中的相邻2种或3种流域同时出现在塔内不同高度上。提出了不同轴向位置流域转变的判据。并发现,同一截面的不同径向位置基本处于同一流域内。同时研究了鼓泡塔内气含率在轴向上的分布规律,给出了不同流动域内气含率的关系式。     

鼓泡塔中非牛顿流体体系气含率的研究

本文是在直径为0.1m、高为1m的鼓泡塔中,选用水、Na_2SO_3/CMC溶液,CMC溶液作为介质,采用单孔喷嘴布气,孔径为0.01m,测定了鼓泡塔的气含率,对实验数据进行了关联,提出了气含率的关联式,并与文献中有关结果进行了比较。     

用人工神经网络方法预测鼓泡塔气含率

A new correlation for the prediction of gas hod up in bubble columns was proposed based on an extensive experimental database set up from the literature published over last 30 years .The updated estimation method relying on artificial neural network,dimensional analysis and phenomenological approaches was used and the model prediction agreed with the experimental data with average relative error less than 10%.     

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。     

高气速下鼓泡塔中气含率分布的测定

在内径476 mm的鼓泡塔内用压差法测定全塔平均气含率与表观气速的关系,进一步利用响应特性良好的双电导探针,考察了不同气速下局部气含率的分布规律。实验结果表明,利用探针法计算得到的全塔平均气含率值与压差法测定值平均误差仅为4.5%,表明探针法测量局部气含率的可靠性良好。实验还表明在高气速下,除分布板影响区外,局部气含率均类似抛物线型分布;随着气速增加,气含率分布趋于陡峭。以实验为依据,拟合了不同气速下(0.05~1.0 m/s)鼓泡塔中局部气含率的关联式,认为塔内局部气含率与径向位置、表观气速和塔径等因素有关。     

AN EXPERIMENTAL STUDY OF GAS HOLDUP IN TWO-PHASE BUBBLE COLUMNS WITH FOAMING LIQUIDS

Gas-liquid upward flow experiments have been performed in two bubble columns of different diameters (0.10 and 0.29 m,) using air as gas phase and several liquids: water, aqueous solutions of ethanol and glycerine, kerosene, and a solution of a surfactant in kerosene. The main goal of the study is the analysis of foaming systems, including the comparison of their behavior with respect to non-foaming systems. The gas holdup was determined experimentally as a function of the gas and liquid superficial velocities in bubbling, churn-turbulent and foaming regimes. It was found that, for foaming systems, semi-batch operation enhances foam formation, yielding higher holdups than those obtained in continuous operation at very low liquid velocities. Opposite to what is observed in non-foaming systems, the liquid superficial velocity affects the gas holdup appreciably in foaming systems. An increase in column diameter results in a decrease in gas holdup for all the systems studied. In aqueous foaming systems, this trend is more drastic since foam is inhibited as the column diameter increases.     

CONTRIBUTION TO HEAT TRANSFER IN AIR-LIFT AND BUBBLE COLUMN FERMENTORS WITH NEWTONIAN AND NON-NEWTONIAN SOLUTIONS

Heat transfer in five air-lift and bubble column bioreactors has been investigated. Water (Newtonian) and xanthan solutions (non-Newtonian) were used. The effects of superficial gas velocity, liquid-phase viscosity and riser-to-downcomer cross-section area ratio have been studied. In air-lift slightly higher heat transfer coefficients were observed than in bubble column reactors. The superficial gas velocity and the effective liquid-phase viscosity influence strongly the heat transfer performance in all systems studied. Following the surface renewal concept, general correlations for heat transfer in Newtonian and non-Newtonian fermentation broth were developed. They describe precisely heat transfer coefficients in a wide range of operating and geometrical conditions.     

EFFECT OF OPERATING CONDITIONS ON GAS HOLDUP IN SLURRY BUBBLE COLUMNS WITH A FOAMING LIQUID

This work presents experimental data on gas holdup in slurry bubble columns with a foaming liquid. The effects of solids concentration, solid particle size, superficial phase velocities and column dimensions on the gas holdup are analyzed. At low superficial gas velocities (less than 4cm/s), for which the liquid does not foam, the presence of solids with small particle size does not affect the gas holdup whereas solids with large particle size induce foam formation and thus their presence increases the gas holdup. In the foaming regime, an increase of solids concentration decreases the gas holdup. The operating mode has a strong effect on the gas holdup: the semi-batch operating mode (stagnant liquid-solid suspension) increases the ability of the liquid to foam with respect to the continuous mode. Regarding the effect of column dimensions, the results presented show that the height of the bubble column does not affect at an appreciable extent the gas holdup in the range 6 < LID < 12. At high gas velocities (greater than 6 cm/s) the gas holdups obtained in a 30 cm-internal diameter column are the same as those measured in a 10 cm-internal diameter column.     

HYDRODYNAMIC STUDIES IN FISCHER-TROPSCH DERIVED WAXES IN A BUBBLE COLUMN

Gas hold-up and Sauter mean bubble diameter measurements were made in a 0.051 m diameter by 3 m long glass bubble column in the system, nitrogen-molten wax, with three different waxes (paraffin wax FT-300, Sasol's Arge wax and Mobil's reactor wax). Paraffin wax has a tendency to foam and gas hold-up is a strong function of gas distributor type, temperature and start-up procedure, whereas the reactor waxes do not foam and are much less affected by these variables, In experiments at 265°C with a 1.85 mm single hole orifice plate distributor the gas hold-ups were nearly the same for all three waxes. However, significant differences in Sauter mean bubble diameters were obtained in experiments with different waxes; FT-300 wax produced the smallest Sauter mean bubble diameters whereas Mobil's reactor wax produced the largest bubbles. Addition of 1-octadecanol and octadecanoic acid (up to 10wt%) to the FT-300 paraffin wax caused an increase in gas hold-up and a delay in the foam break-up in runs at 265°C with the 1.85 mm orifice plate distributor.     

导流管型鼓泡塔中牛顿型和非牛顿型液体的氧传递系数

在塔径分别为φ0.188m和φ0.112m各三组不同直径导流管的中心区充气塔中，测定水和CMC溶液的氧传递系数并提出关联算式.讨论中心区充气和环隙区充气塔的不同管径比Di／D0对氧传递系数HLa和液体循环的影响.无论在空气－水或空气－CMC溶液体系，结构参数Di／D0值在0.6左右，液体循环时间和KLa值为最小     

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。     

气液及气液固三相浆态鼓泡塔的气相轴向返混系数

气液及气液固三相浆态鼓泡塔的气相轴向返混系数宋同贵，赵玉龙，苏晓丽，张碧江（中国科学院山西煤炭化学研究所，煤转化国家重点实验室，太原０３０００１）关键词：气液鼓泡塔，浆态鼓泡塔，气相轴向返混１前言在鼓泡塔反应器的设计、放大及数学模拟中，气相轴向返混系...     

EFFECT OF SURFACTANT CONCENTRATION ON GAS HOLDUP IN A BUBBLE COLUMN WITH AN ORGANIC LIQUID

This work presents an experimental analysis of the effect of the addition of a surfactant on gas holdup in a bubble column with an organic liquid phase. For the system considered, the addition of surfactant increases the gas holdup by increasing the volume of foam within the column. The surfactant concentration has negligible effect on the intrinsic gas holdup of both the bubbling and foaming regions.