气液传质理论研究进展

文内对气液传质的理论研究进行了评述，并预测了未来的发展方向     

超声内环流气升式反应器传质性能的研究

研究了超声内环流气升式反应器中空气-水-离子交换树脂体系的气液传质与液固传质性能.分别采用电极动态法和离子交换树脂法实验测定了气液传质和液固传质系数.重点考察了表观气速、超声电功率对于气液传质系数以及液固传质系数的影响.实验表明,内环流气升式反应器中表观气速对于气液传质性能影响较大,而超声作用对气液传质影响不大.该反应器中液固传质系数随表观气速的增加而增大;无超声作用情况下,当表观气速达到一定程度时,液固传质系数保持一恒定值.超声作用时,气速增加到4 cm·s-1左右,传质系数达到最大值,随后液固传质系数随着表观气速的增加而逐渐减小,传质系数仍然大于无超声作用时的值.超声对液固传质有较强的促进作用,电功率在150 W左右时,超声对液固传质的促进作用最佳,是不加超声作用时传质系数的两倍左右;但随着电功率的进一步增大,液固传质系数呈现下降趋势.     

陶瓷膜曝气强化臭氧传质研究

为了探究陶瓷膜曝气对臭氧气液传质的影响,对三种陶瓷膜进行了性能的表征与评价,并从陶瓷膜孔径、臭氧投加量、进气流量、温度、pH等方面对液相臭氧浓度和表观传质系数进行了考察。结果表明：1号陶瓷膜传质效果最好,其液相臭氧平衡浓度和表观体积传质系数（K_La）分别为微孔曝气的3倍和2.1倍。最佳的液相平衡臭氧浓度（10.20 mg/L）和K_La(0.519 2 min^-1)在1号陶瓷膜、臭氧投加量为43.92 mg/L、温度20℃、进气流量400 L/h,pH为7条件下取得。     

废水厌氧生物处理装置中的三相分离器

综述了厌氧消化系统中三相分离器的各种结构形式及其特点，重点分析了影响分离器分离效率的各种因素，并就分离器的关键尺寸设计进行了探讨。     

加入第二液相强化气液传质

以水吸收二氧化碳为研究体系,考察了第二液相(有机相)的加入对气液传质的增强作用.运用经验关联式,对气泡平均直径进行了预测,应用渗透模型计算并讨论了第二液相的加入对气液接触界面积、体积传质系数的影响.实验结果表明:不同搅拌速度对气泡大小影响不同,适宜的搅拌速度有利于传质;少量的第二液相的加入减少了气泡聚并现象,增大了气液接触界面积.气液传质增强效果用增强因子表示.     

应用水解—好氧生物法处理中药厂废水

中成药废水经过水解－好氧工艺处理,达到国家排放标准,工艺流程简单可行,处理效果好,便于管理,操作简单,投资省。     

物理场强化气液传质的研究进展

分别简述了磁场、电场、电磁场、超声场和超重力场5种物理场的作用机理,综述了这些物理场在强化蒸发、精馏和气体吸收等气液传质过程中的研究进展,同时概述了物理场强化气液传质的热力学研究进展。分析表明,物理场强化气液传质在化工、环保和节能减排等领域具有广泛的应用前景,但目前的研究大多还处于实验阶段,其机理和各种因素对强化效果影响的研究还不够深入和完善。指出今后研究热点主要包括：继续探索物理场强化传质的作用机理,拓展其应用领域,并对过程中的瓶颈问题进行技术攻关;通过实验和热力学研究两种方法对不同种类物理场强化传质效果进行比较,以确定各种物理场的适用体系。     

内循环生物流化床曝气过程氧传质特性研究

针对水-空气-高分子颗粒三相体系,测试了内循环好氧生物流化床曝气过程中气-液相间氧传递的体积传质系数KLa,分析了操作参数(进气量QG、固含率εs和升降流区截面积比Ar/Ad)对氧传质系数KLa的影响。结果表明,KLa随着进气量的提高呈线性增加趋势;固含率对KLa有正反两方面的作用,存在一个较适宜的固含率使氧传质效率达到最高;随升降流区截面积比Ar/Ad的增大,KLa随之提高。基于KLa影响因素的分析对实验数据进行拟合,建立了关于体积传质系数KLa的关联式:Kd=2.23×10-6Reb0.582Ab0.976εs0.016。该关联式预测结果与实验数据吻合良好,对类似流化床反应器的设计有一定参考价值。     

第三组分强化气液传质的研究进展

综述了加入第三组分强化气液传质过程的研究,分别介绍了表面活性剂、固体微粒以及第二液相作为第三组分加入对气液传质过程的增强研究,叙述并讨论了强化传质机理研究的最新进展。     

微量醇及电解质强化气液传质的研究

在气升式内环流反应器中考察了微量醇类物质(乙醇、叔丁醇、季戊四醇)及电解质(CaCl2)对氧的液相体积传质系数和气含率的影响。结果表明,向空气-水体系中添加微量醇类物质可以明显改善气液传质性能,同时醇类物质强化气-液传质存在一极限浓度,超过此浓度后,氧的液相体积传质系数略有降低;当表观气速增加时,去离子水体系和含醇体系的气含率都增加,但醇体系的气含率明显高于去离子水体系。此外,添加电解质CaCl2也会使氧的液相体积传质系数有所提高,并从离子强度的角度对其抑制气泡聚并的机理进行了分析。     

生物填料塔处理餐厅污水传质反应研究

从传质和生化反应基本过程出发,将复杂的生物填料塔中三相传质-生化反应综合简化为一个有效生化反应过程,并得到其数学模型,模型综合参数———总传质有效因数ηt可通过容易测定的本征反应和实际反应速率来确定;实验研究了入塔污水CODC r和入塔水量对总传质有效因数影响,结果表明,入塔污水CODC r较高时,有较大的总传质有效因数;当入塔水量增大,传质效果增加,总传质有效因数增大。     

微孔膜气体分布器气液传质比表面积的研究

研究了以微孔膜作为气体分布器的反应器的气液传质比表面积,主要考察了气体流量、液面高度、表面张力等操作因素对气液传质比表面积的影响。结果表明,气液传质比表面积随着气体流量的增大先呈增大的趋势,到一定值时,开始呈减小趋势;随着表面张力的增大而减小;随着液面高度的增大缓慢减小。与传统塔设备比较,微孔膜气体分布器的气液传质比表面积要高,分布器强化了气液传质过程。最后,运用量纲分析方法对试验数据进行非线性回归得到关于气液传质比表面积的关联式,此式较好地吻合了试验数据。     

三相生物流化床技术现状及其在含油废水处理中的研究进展

作为一种新型的废水生物处理技术,三相生物流化床反应器近年来备受关注。本文从流体力学性能、气液传质特性、反应器结构设计、生物载体等方面对三相生物流化床的技术特点及研究现状进行了综述,表明该类反应器在内部流体力学特征和传质特征方面较其它生物反应器更为复杂,反应器结构、运行参数及载体的选择对处理效果有较大影响;同时总结了其在含油废水处理中的研究成果和进展;最后指出：用于指导反应器结构设计的数学模型的建立及反应器的工程验证仍是该技术今后研究开发的重点。     

Numerical modeling of mass transfer processes coupling with reaction for the design of the ozone oxidation treatment of wastewater

A computational model for an ozone oxidation column reactor used in dyeing wastewater treatment is proposed to represent, simulate, and predict the ozone bubble process. Considering the hydrodynamics, mass transfer, and ozone oxidation reaction, coupling modeling can more realistically calculate the ozone oxidation bubble process than the splitting methods proposed in previous research. The modeling is validated and shows great consistency with experimental data. The verified model is used to analyze the effect of operating conditions, such as the initial gas velocity and the ozone concentration, and structural conditions, such as multiple gas inlets. The ozone consumption is influenced by the gas velocity and the initial ozone concentration. The ozone’s utilization decreases with the increasing gas velocity while nearly the same at different initial ozone concentrations. Simulation results can be used in guiding the practical operation of dyeing wastewater treatment and in other ozonation systems with known rate constants in wastewater treatment.     

高效好氧生物处理印染废水的方法与实践

通过用高效好氧生物法处理某厂印染废水的工程实例证明,处理后的废水COD去除率达到93.6%,BOD5去除率达到93.9%,出水水质能够满足GB 4287-1992<纺织染整工业水污染物排放标准>二级标准的要求.该工程工艺的优点为:基建费用低,空气氧转化利用率高,容积负荷和污泥负荷高,剩余污泥量少,抗冲击负荷能力强,系统操作简便灵活.     

Oxygen mass transfer in a gas/membrane/liquid system surrogate of membrane blood oxygenators

Oxygen mass transfer in a membrane blood oxygenator (MBO) surrogate system has been addressed in this work. It consists of a slit for water circulation as a surrogate blood flow channel and a constant pressure oxygen chamber separated by an integral asymmetric hemocompatible polyurethane‐based membrane. The oxygenated stream enters a well‐mixed reservoir of constant volume, V, for the oxygen average concentration, , measurement as a function of time, t. In a range of short times, the linearity of vs. t allows the direct determination of the permeation fluxes , with no recourse to dimensionless correlations for the determination of mass‐transfer coefficients. The experimental fluxes are in very good agreement with the predictions based in unidimensional axial convection and unidimensional transversal diffusion. This custom‐made benchmark system allows the optimization of the flow and oxygen mass transfer for the design of a novel flat‐sheet MBO. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3756–3763, 2018     

Gas-liquid mass transfer in two and three-phase upflows through a vertical tube

Oxygen absorption rates were measured to determine volumetric coefficients of gas-liquid mass transfer coefficients k_La in gas-liquid and gas-liquid-solid upward flows through a vertical tube. The liquid was deionized water or aqueous glycerol solution, and the solids were glass beads or polystyrene beads. The dependencies of k_La on gas velocity, liquid velocity, temperature, solid material, and solid concentration were examined. The experimental results were correlated with empirical equations. The mechanisms of the solid loading effect are discussed.     

整体式床层中液体分布与气-液传质的关系

With a particular focus on the connection between liquid flow distribution and gas-liquid mass transfer in monolithic beds in the Taylor flow regime, hydrodynamic and gas-liquid mass transfer experiments were carried out in a column with a monolithic bed of cell density of 50 cpsi with two different distributors (nozzle and packed bed distributors). Liquid saturation in individual channels was measured by using self-made micro-conductivity probes. A mal-distribution factor was used to evaluate uniform degree of phase distribution in monoliths. Overall bed pressure drop and mass transfer coefficients were measured. For liquid flow distribution and gas-liquid mass transfer, it is found that the superficial liquid velocity is a crucial factor and the packed bed distributor is better than the nozzle distributor. A semi-theoretical analysis using single channel models shows that the packed bed distributor always yields shorter and uniformly distributed liquid slugs compared to the nozzle distributor, which in turn ensures a better mass transfer performance. A bed scale mass transfer model is proposed by employing the single channel models in individual channels and incorporating effects of non-uniform liquid distribution along the bed cross-section. The model predicts the overall gas-liquid mass transfer coefficient with a relative error within ±30%.     

第二液相的加入对气液传质系数的影响

以搅拌罐中的水吸收CO2为研究体系,分别采用异戊醇、苯和正己烷为第2液相,通过实验考察了第2液相的加入对气液传质的影响.实验结果表明:第2液相的加入对气液体积传质系数KLa有很大的影响,且不同的第2液相的影响程度也不同.在一定的操作条件下,KLa均随搅拌速度和第2液相体积分数的增加呈先增大后减小的趋势,随表观气速(在一...