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。     

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。     

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.     

鼓泡床反应器中气液分配器对气含率的影响

以水和空气分别模拟工业上的重质原油和氢气迚行冷模试验,考察鼓泡床反应器新型气液分配器对气含率的影响,迚而优化幵确定气液分配器的结构形式和结构参数。试验结果表明,气液分配器对总体平均气含率的影响,随表观气速的增大基本呈线性增长,与其他鼓泡床迚料内构件结构的影响基本一致,幵且稍高一些(3%~5%)。对局部气含率的影响:轴向上,在测试范围内,轴向位置越高,气含率越高,主要和泡罩式气液分配器结构有关;径向上,气体在床层中分布不均匀,中间多,近壁少,同一高度时,中心处气含率一般为近壁气含率的1.5~2倍。     

大型加压环流反应器局部气含率及气泡行为研究

为了将环流反应器引入煤炭液化领域,建立了大型环流反应器冷模试验装置.进行了氮气一水体系及其他体系的冷模运转试验,对环流反应器内小同部位的局部气含率进行了比较分析,并考察了压力和气体密度的影响.对反应器内的大小气泡上升速率进行了尝试汁算,得出了有重要意义的结论.     

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。     

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。     

鼓泡塔中气泡尺寸分布和局部气含率研究

在内径为0.38 m的鼓泡塔中采用双电导探针法对不同通气速率下的气泡尺寸分布和局部气含率进行了实验研究,分析了气泡尺寸的概率密度分布。结果表明:气泡尺寸随轴向高度的增加而增大,随径向距离增加而减小;鼓泡塔中气液流动可分为过渡流域和充分发展流域,在过渡流域气含率随轴向高度增加而增大,在充分发展流域气含率趋于均值,径向局部气含率分布呈抛物线型下降。高气速下气泡尺寸概率密度分布比低气速下宽,且随轴向高度的增加分布变宽。     

Hydrodynamics of the flow transition from a bubble column to an airlift-loop reactor

The hydrodynamics of an airlift-loop reactor (ALR) and a bubble column (BC) were studied in the same reactor unit. When the liquid circulation in the ALR was impeded gradually in order to obtain a BC mode of operation, there was a transition flow regime inbetween that of the ALR-type flow and the BC-type flow. In the BC the heterogeneous flow was represented by an instationary circulatory flow pattern and characterized by a liquid circulation velocity. The liquid flow in the ALR was represented by a drift-flux model. In the transition flow regime, hydrodynamic calculations based on the plug-flow behavior of an ALR appeared to be valid up to a certain defined value of the total gas-liquid flow rate. To distinguish between BC and ALR flow characteristics, a simple criterion is proposed, qualifying that the distinction between both flow patterns is determined by the superficial liquid velocity and the liquid circulation velocity. If the latter velocity exceeds the superficial liquid velocity a hydrodynamic transition will occur from a uniform ALR type of flow to a heterogeneous BC type of flow. The criterion coincides with an empirical power law function in which the liquid velocity is given as a function of the gas velocity. The values of the power-law coefficients depended on the characteristics of the two-phase flow. The change in value cohered with the onset of a change in the flow pattern.     

筛板结构对多级鼓泡塔中流体力学参数的影响

在外径0.3 m的多级鼓泡塔中采用双探针电导探头考察了筛板结构对鼓泡塔中筛板上下两处流体力学参数的影响,并与无筛板鼓泡塔中流体力学参数进行了对比。研究结果表明:带筛板的鼓泡塔中气含率径向分布规律和无筛板的鼓泡塔相类似,筛板上下二侧的平均气含率随表观气速的增加而增加;在鼓泡塔轴向位置上,筛板下侧的气含率普遍比筛板上侧气含率要高;筛板的孔分布方式对于气含率径向分布有着一定影响,但孔径大小对此影响较小。     

热管式固定床鼓泡反应器返混试验研究

为了研究热管式固定床鼓泡反应器的返混问题,采用脉冲法,在一内径为50mm、高800mm,床内充以多孔填料,内插一根16mm×2mm不锈钢-水热管的固定床反应器中,用并流向上的水和氮气进行返混试验研究。利用轴向扩散模型计算反应器轴向Peclet准数,考察了气相流速、液相流速、多孔介质和热管对返混的影响。研究表明反应器中热管的存在加重了返混。     

Modeling of vanillin production in a structured bubble column reactor

Vanillin is an important flavour. Semi-synthetic vanillin can be produced by the oxidation of lignin. Experimental studies leading to vanillin production in a batch reactor and a structured bubble column reactor (SBCR) lead us to the conclusion that the SBCR could have non-idealities such as dispersion. The radial and axial liquid-phase dispersion within the packed criss-crossing sandwich structures of Mellapak-750Y had been studied. A 2D model accounting for axial and radial velocities and dispersion was formulated and solved. The model predictions were compared with that of an experimental residence time distribution curve. The axial dispersion coefficient of the liquid phase is of the same order of magnitude as the radial dispersion coefficient. The reaction kinetics available in literature is adopted for the present study. Model for the SBCR was formulated and simulated using commercial modeling software. Simulation experiments were conducted in a SBCR. The effect of the following parameters on the yield of vanillin is studied: lignin concentration, lignin molecular weight, oxygen partial pressure and reaction temperature. It can be said that lignin molecular weight is a crucial parameter in vanillin production.     

Void fraction distribution in a bisectional bubble column reactor

This article presents the distribution of the local void fraction (α) in a mock-up bisectional bubble column with a diameter of 0.63 m. Owing to the lack of such data in the literature, α was investigated experimentally using a microresistivity (R) probe and a phase discrimination procedure based on the probe signal. The two-phase mixture that consisted of air and tap water was measured at 342 nodes in the vertical half-section plane of the column. Relatively small differences between the volume-integrated local values of α and the measured total gas holdups showed reasonably good agreement under all conditions. Experimental data were used for validation of a bubble column numerical model for a low hydrodynamic regime with commercial computational fluid dynamics (CFD) code. The difference between the CFD calculated total gas holdup and the experimentally measured mean value is 8.8%, while some differences in the local void fraction distributions were found in the lower part of the column. © 2019 American Institute of Chemical Engineers AIChE J, 65: 1186–1197, 2019     

PX氧化鼓泡塔反应器流动规律的研究

采用改进的Pavlov管测定鼓泡塔中的液相局部流速,采用电导探针方法测定气含率分布,测定了3种塔径（D200mm,D500mm,D800mm）、不同空塔气速下的流速三维分布和气含率分布。     

Gas holdup in a bubble column with immikible liquid mixtures

Experimental measurement of gas holdup was carried out in a medium-size gas-liquid-liquid bubble column with a multiple nozzle sparger plate using air, water and organic liquids. It was found that the fractional holdup depends on gas velocity, liquid properties, phase inversion in the liquid mixture as well as spreading coefficient of the organic liquid. In the presence of a liquid with a negative spreading coefficient the holdup is a minimum at the phase inversion point. but the reverse is true for a liquid with a positive coefficient of spreading. Observed bubble characteristics have been discussed. Correlations for gas holdup have been developed for different ranges of liquid composition.     

Axial dispersion and oxygen transfer in the transition from bubble column to airlift-loop reactor

Axial dispersion and oxygen transfer were investigated in a bubble column (BC) with a circulation loop. A butterfly valve, situated at the bottom of the loop enabled the above-mentioned physical characteristics in the transition regime between typical airlift-loop-reactor (ALR) flow and BC flow to be studied. The Bodenstein number was found to decrease when the liquid velocity was reduced, implicating a less established plug-flow character. The number of circulations required to achieve complete mixing in the reactor was diminished if the liquid circulation was hampered and appeared to be proportional to the Bodenstein number. The volumetric oxygen-transfer coefficient was estimated by an ideally stirred-tank-reactor (STR) model and a plug-flow model. The STR model yielded reliable results for the whole range of operation while the plug-flow model only appeared to be appropriate for the ALR operation mode. The k_La values obtained were included in a generalized correlation for the transition flow regime and were found to increase gradually when the circulation velocity was reduced.