微通道内伴有化学吸收气液两相流的空隙率与压力降

微通道内气液两相流空隙率与压力降对微反应器的热质传递性能有显著影响,是微反应器的重要设计参数。采用高速摄像仪和压力测量系统分别对矩形微通道内单乙醇胺水溶液化学吸收CO₂过程的空隙率和压力降进行了研究,考察了弹状流下气液两相流量与化学反应速率对空隙率及压力降的影响。结果表明:当液相流量一定时,微通道内空隙率和压力降均随着气相流量的增大而增大,空隙率随化学反应速率的增大而减小,压力降随化学反应速率的增大而增大;当气相流量一定时,随着液相流量和化学反应速率的上升,微通道内空隙率下降,而压力降上升。提出了微通道内伴有化学吸收的空隙率和压力降的半理论预测模型,模型平均误差分别为15.79%和11.12%,显示了良好的预测性能。     

单乙醇胺水溶液化学吸收CO_2的研究

有机胺水溶液化学吸收CO2在工业上广泛应用,对其传质过程的微观机理进行研究十分必要。文中以对流扩散方程为基础,考虑了界面阻力对传质的影响,建立了带有化学反应的气液吸收过程液相侧非稳态传质模型,得到了传质系数表达式。利用激光全息干涉仪对不同液相主体流速下单乙醇胺(MEA)水溶液化学吸收CO2过程进行了实验研究,测定了传质达到稳态时的液相侧近界面浓度、浓度边界层厚度和传质系数。结果表明:随着液相主体流速的增加,近界面浓度和浓度边界层厚度减小,而传质系数增大;MEA在水溶液中的质量分数由0.1%增大到0.2%时,CO2吸收过程达到稳态时的近界面浓度、浓度边界层厚度及传质系数均增大。传质系数模型计算值与实验值吻合良好。     

加氢尾油非临氢降凝生产润滑油基础油

以加氢尾油为原料,采用非临氢降凝工艺生产润滑油基础油。结果表明,基础油收率大于75%,100 YF白油和150 YF白油黏度指数均大于100,同时可生产链烷烃和液化气。     

单泡吸收过程的界面传质机理

This paper focuses on the mechanism of interfacial mass transfer of a single bubble, based on the chemical potential driving force, an approach for calculating interfacial concentration in practical process is proposed. The absorption processes of bubble under both quiescent and mobile conditions are analyzed and discussed respectively. For a stationary absorption, only in the case of liquid bulk concentration near saturated value, the interfacial concentration could close to the equilibrium value ; For a moving bubble, under ordinary operating condition （Yo〉l）, the interfacial concentration is far from its equilibrium. Only under bulk concentration near saturated value or a smaller Yo（Yo〈0.1） which may involve the complication of additional resistance at interface induced by surface contamination or surfactant added, the interfacial concentration could be approximate to equilibrium value. The interfacial concentration close to the interface on liquid side for a single CO2 bubble absorbed by methanol is measured using a modern optical instrumentation in which the laser holographic interference method is adopted with a real-time and amplification technique. Experimental results show that the interfacial concentration decreases significantly with increasing Re and is far from the equilibrium one in a larger Re range. Experiments validate the proposed model.     

阵列凸起微通道内气液两相传质特性研究

研究了阵列凸起微通道内N-甲基二乙醇胺（MDEA）吸收CO₂过程的气液两相传质特性。在弹状流型下,考察了气液两相流量、MDEA浓度对体积传质系数、CO₂吸收效率、压力降以及能量损耗的影响。弹状气泡受到阵列凸起的挤压作用发生形变,促进了气液两相间的传质。与平滑通道相比,阵列凸起微通道在实验条件下具有更好CO₂吸收效率。在相同的能量损耗时,阵列凸起微通道具有更大的体积传质系数。     

T型微通道内浆料体系中气泡的生成动力学

实验研究了T型微通道内浆料体系中弹状气泡的生成动力学,重点考察了颗粒粒径的影响。气泡的生成过程可划分为四个阶段：填充阶段、挤压阶段、过渡阶段和快速夹断阶段。在填充阶段、挤压阶段和快速夹断阶段,气泡最小颈部宽度与时间呈幂律关系。在过渡阶段,气泡最小颈部宽度与时间呈线性关系。浆料体系中气泡的挤压阶段和过渡阶段随颗粒粒径的减小而缩短。连续相流量及颗粒粒径对填充阶段幂律指数无显著影响;挤压阶段和快速夹断阶段的幂律指数以及过渡阶段的线性斜率均随颗粒粒径的增大而减小,随连续相流量的增大而增大。     

从混合二羧酸中分离制取高纯戊二酸

己二酸生产过程副产大量的混合二羧酸,其中富含的戊二酸是一种应用广泛的精细化工原料.本研究从混合二羧酸中分离制取高纯戊二酸进行了研究.提出了一种包括溶解结晶、氧化镁反应分离和真空精馏的新工艺,确定了适宜的工艺条件,得到了质量分数大于99.5%的高纯戊二酸.     

非牛顿流体中气泡上升及聚并过程中液相侧浓度场的数值模拟(英文)

On the basis of Navier-Stockes equation and convection-diffusion equation, combined with surface ten-sion and penetration models, the equations of moment and mass transfer between bubble and the ambient non-Newtonian liquid were established. The formation of a single bubble from a submersed nozzle of 1.0 mm di-ameter and the mass transfer from an artificially fixed bubble into the ambient liquid were simulated by the volume- of-fluid (VOF) method. Good agreement between simulation results and experimental data confirmed the validity of the numerical method. Furthermore, the concentration distribution around rising bubbles in shear thinning non-Newtonian fluid was simulated. When the process of a single ellipsoidal bubble with the bubble deformation rate below 2.0 rises, the concentration distribution is a single-tail in the bubble’s wake, but it is fractal when the bubble deformation rate is greater than 2.0. For the overtaking of two in-line rising bubbles, the concentration dis-tribution area between two bubbles broadens gradually and then coalescence occurs. The bifurcation of concentra-tion distribution appears in the rear of the resultant bubble.     

三维孔喉结构微通道内液滴的破裂行为研究

利用高速摄像仪研究了三维孔喉结构微通道内液滴的破裂行为。采用不同黏度的甘油-水溶液作为分散相,含4%(质量)表面活性剂(Span 20)的矿物油作为连续相。液滴通过孔喉结构后,观察到了三种流型:球形破裂、非球形破裂和不破裂。除极低连续相毛细数的情形外,分散相黏度和两相流量的增加不利于液滴破裂,液滴的破裂位置均接近于喉道出口。研究了液滴的球形破裂,结果表明,球形破裂中子液滴平均尺寸随分散相黏度和连续相流量的增加而降低,且与两相总毛细数呈幂律关系,模型预测值与实验结果吻合良好。     

Y型微通道内纳米颗粒稳定气泡的完全阻塞破裂动力学

研究了Y型微通道吸附型纳米颗粒稳定气泡的完全阻塞破裂的动力学,破裂过程可划分为挤压阶段和快速夹断阶段,两阶段内无量纲气泡最小颈部宽度与时间均呈幂率关系。气泡破裂过程的颈部动力学表明颗粒的存在并不影响两阶段转变的临界颈部宽度,但吸附在气泡表面的颗粒层会减弱挤压阶段中连续相对气泡颈部的挤压作用,以及快速夹断阶段角区中连续相液体回流对气泡的挤压作用,进而阻碍气泡颈部的形变,延长了气泡的破裂过程。纳米颗粒稳定的气泡的指前因子m及幂率指数α均小于常规气泡,但其差值随着毛细管数Ca和气泡长度l₀的增大而减小,颗粒对气泡破裂过程的影响逐渐减弱。此外,纳米颗粒稳定的气泡的头部曲率略小于常规气泡,颗粒对完全阻塞破裂过程气泡头部动力学的影响可以忽略。