滴流床中固相润湿分数的实验研究

用表面镀镍的填料颗粒化过氧化分解的化学反应法，测定了内径７５ｍｍ的滴流床中固体填料的外润湿分数，实验结果表明，润湿分数随表现气速和液速的增加而增加，降低液体的表面张力，增大粘度也有利于提高润湿分数，当表现液速达到５ｋｇ／（ｍ＾２．ｓ）时，固体填料基本上完全润湿，这与文献报道和作者数值模拟结论一致。     

微生物脱砷预处理难冶含砷金矿提金的研究

用化能自养的氧化铁硫杆菌和氧化硫硫杆菌，对河北半壁山含砷金精矿进行了公斤级的预处理氧化脱砷实验．在细菌预处理反应器中的连续和批式脱砷实验表明，目前选育的菌种是有效的．严格控制工艺条件，可以在4天左右便脱砷率高于80％．后续氰化提金实验证实，金的总回收率可达90％以上．用微生物脱砷预处理难冶含砷金矿有金浸出率高、便于固定浸出的砷、免除对环境污染的优点，是有很好应用前景的处理难冶含砷金矿的技术路线．     

Numerical solution of viscous flow past a solid sphere with the control volume formulation

The control volume formulation with the QUICK finite difference scheme is used to solveincompressible liquid flow past a solid sphere in terms of stream function and vorticity.Several tech-nical points are addressed on improving the accuracy and efficiency of numerical simulation of similarproblems of fluid flow.In particular,the importance of suitable specification of the distortion func-tion to enforcing the far field boundarv conditions is emphasized.     

Numerical Study of Solid-Liquid Two-Phase Flow in Stirred Tanks with Rushton Impeller (Ⅰ) Formulation and Simulation of Flow Field

Three-dimensional solid-liquid flow is mathematically formulated by means of the "two-fluid" approach and the two-phase k-ε-Ap turbulence model. The turbulent fluctuation correlations appearing in the Reynolds time averaged governing equations are fully incorporated. The solid-liquid flow field and solid concentration distribution in baffled stirred tanks with a standard Rushton impeller are numerically simulated using an improved "inner-outer" iterative procedure. The flow pattern is identified via the velocity vector plots and a recirculation loop with higher solid concentration is observed in the central vicinity beneath the impeller. Comparison of     

HYSTERESIS OF GAS-LIQUID MASS TRANSFER IN A TRICKLE BED REACTOR

1 INTRODUCTIONTrickle bed reactors are widely used in the process industry,particularly in petroleumhydroprocessing operations,and have been extensively studied by chemical engineers.In atrickle bed reactor,the gas and liquid flow cocurrently down through the packed bedand undergo chemical reactions.However,there exist multiple hydrodynamic stateswhich correspond to either uniform or,in most cases,nonuniform radial distributionof the gas and liquid flows in the packed section.Moreover,the hydrodynamic state is     

用单元胞模型数值模拟气泡群中气泡的运动

用数值方法模拟了气泡群中Reynolds数为50的气泡的运动,以单元胞模型体现气泡群中气泡间的相互作用。数学模型用完全的流体力学方程、以流函数-涡度为变量来描述变形气泡周围的液体流动,控制方程在贴体正交坐标系中、以有限差分法离散后数值求解。模拟结果表明,气含率对气泡阻力系数和气泡偏心率有很大的影响,与理论分析较符合。但单元胞模型预测的阻力系数与基于爬流中球形气泡的理论值相比,在数值上偏高很多。采用无剪切为外边界条件比用无涡度为外边界条件的模型预测更接近理论公式。预计单元胞模型经进一步改进后可成为处理气泡群的有效工具。     

硫酸盐还原菌的固定化

针对低浓度生物冶金浸出液难以处理的现状,利用硫酸盐还原菌(Sulfate Reducing Bacteria, SRB)沉淀分离有价金属离子的微生物法是很有应用前景的处理方法. 本工作以提高SRB的还原活性为出发点,通过间歇式实验首先确定适宜的初始COD/SO42-比值和pH值,进而探讨固定化载体对SRB还原性能的影响. 研究结果表明,初始COD/SO42-比值为3、初始pH值为7时SRB具有较高的生物活性. 影响生物膜形成及SRB活性的首要因素是固定化载体的表面粗糙度,其次是孔容. 表面光滑的惰性玻璃珠作为载体时没有生物膜形成,SRB的活性低,SO42-的去除率仅为50%;其他载体均观测到生物膜,且载体的孔容越大,SRB的SO42-去除率也越高. 从SO42-的去除效果和工艺的稳定性考虑,多孔聚氨酯泡沫是较优的固定化载体,SRB的还原活性高,SO42-的去除率高达95%,工艺操作简便.     

搅拌槽内多相流动数值模拟研究进展

综述了过程工业中广泛应用的搅拌槽反应器内多相流动数值模拟研究的进展.讨论多相湍流模型、相间作用力模型及搅拌桨处理方法等重要的数值模拟技术和方法,并对有关的计算模型进行了比较分析.针对搅拌槽内的各种多相体系,论述了不同研究者在桨区处理、相间动量传递描述和分散相的引入对体系湍流特性影响等方面的模拟方法并对结果作了比较.提出了需要进一步深入研究的课题.     

NONUNIFORMITY OF TWO PHASE FLOW IN CAPILLARY SYSTEMS

Gas-liquid flow in simple systems consisting of capillaries is analyzed by theory of irreversible thermodynamics so as to shed light on induction of nonuniformity of multiphase flow. By the Prigogine's theorem of minimum entropy production, stability of uniform two-phase flow and possible transition to nonuniform distribution are discussed. The analysis of model systems suggests potential application of irreversible thermodynamics to research of multiphase hydrodynamics in chemical reactors.     

表面活性剂溶液中单液滴的非稳态运动

A numerical investigation of the unsteady motion of a deformed drop released freely in another quiescent liquid contaminated by surfactant is presented in this paper. The finite difference method was used to solve numerically the coupled time-dependent Navier-Stokes and convective-diffusion equations in a body-fitted orthogonal coordinate system. Numerical simulation was conducted on the experimental cases, in which MIBK drops with the size ranging from 1.24 mm to 1.97 mm rose and accelerated freely in pure water and in dilute sodium dodecyl sulphate (SDS) aqueous solution. The applicability of the numerical scheme was validated by the agreement between the simulation results and the experimental data. Both the numerical and experimental results showed that the velocitytime profile exhibited a maximum rising velocity for drops in SDS solutions, which was close to the terminal velocity in pure water, before it dropped down to a steady-state value. The effect of the sorption kinetics of surfactant on the accelerating motion was also evaluated. It is also suggested that introduction of virtual mass force into the formulation improved obviously the precision of numerical simulation of transient drop motion.