化工分离过程强化的特点及发展方向

介绍了化工分离过程的重要性、复杂性、多样性及面临的机遇和挑战.分析了分离过程强化的新特点,对化工分离过程强化在过程工业可持续发展中的意义和作用进行了讨论.     

超声场对化工分离过程的强化

近年来，超声场强化工分离过程的研究十分活跃，本文比较详细地综述了这一领域的研究进展，并结合化工分离过程的特点，探讨了超场强化化工分离过程的附加效应，为该邻域的研究工作提供了有效的途径。     

基于水力空化的化工过程强化研究进展

水力空化（HC）是一种利用声化学效应（即空泡溃灭时释放出的巨大能量）的高效、绿色化工过程强化技术,是国内外的研究热点。该技术具有设备造价低、可放大性强、可与其他物理及化学方法高效耦合等优点,工业应用前景广泛。本文介绍了HC现象及其特性;归纳了近年来HC技术在有机废水处理、水消毒与生物燃料制备等代表性应用的研究、应用进展以及作用机理,展示了其工业应用的潜力;总结了用于诱发HC现象的水力空化反应器的发展过程与研究现状;最后,结合发展趋势与作者的研究经历,归纳了国内外在HC研究方面存在的问题,指出了其未来发展方向,为HC技术的发展与工业应用探索提供建设性意见。     

微波场强化化工分离过程研究进展

优化化工分离技术、实现化工分离过程的节能减排,一直是化工分离过程研究的热门课题。近年来,微波场强化分离过程的研究非常活跃。本文阐述了微波对物质的作用机理以及微波加热较普通加热的优势与特点;系统介绍了微波场在萃取、精馏、干燥、脱附/吸附、蒸馏和反应精馏等分离过程的强化效果和应用进展,并分析总结了微波场在这些分离过程中的强化机理,分析表明将微波应用于化工分离过程具有加热速度快、产品质量高、耗能低和易于控制等特点;同时指出微波在分离过程特别是蒸馏/蒸发和反应精馏领域研究的欠缺,提出对于微波是否对蒸馏/蒸发或反应精馏过程具有强化作用还需要大量的实验验证和相应的理论支撑;最后本文对微波在分离领域的发展作了分析与展望。     

化工过程分离循环系统的多目标模糊优化研究

Separation-recycle system is an important part in chemical process, and its optimization is a multiobjective problem. In this paper the process optimization procedure is proposed. The fuzzy optimization algorithm with the concept of relative importance degree (RID) is utilized to transfer multi-objective optimization (MO-O) model into a single-objective optimization (SO-O) framework. The treatment of process condensate in synthesisa mmonia plant is taken as example to illustrate the optimization procedure, and the satisfactory result demonstrates feasibility and effectiveness of the suggested method.     

化工过程强化的理论与实践初探

介绍了化工过程强化的含义,并用N,N-二甲基乙酰胺和硫磺回收工艺的模拟、规整填料塔计算机辅助设计计算软件和某化工厂产品的2种工艺方案对比等案例,说明化工过程强化的重要性和已经发挥的作用。认为我国化工过程强化技术与发达国家相比还存在一定差距,应充分结合化工过程强化的理论与实践,在开展基础研究的同时追求开发创新,满足生态经济和可持续发展的要求。     

化工过程强化的研究进展

化工过程强化是实现可持续发展的重点项目之一,本文分别介绍了化工过程强化的技术,包括膜技术、非传统过程、脉动燃烧干燥技术、连续床色谱技术、整体催化技术和信息技术;化工过程强化的设备,主要有超重力旋转填料床、多功能反应器、静态混合反应器、微反应器和膜反应器等;以及化工过程强化目前存在的一些问题。     

单元操作的过程强化

过程强化研究渐成热点,过程技术和设备是化工过程强化的两个方面。单元操作是化工过程基本操作,其过程的强化对化工过程有较大的影响。本文综述了化工原理课程中各主要单元操作的过程强化。     

采用CHEMCAD软件强化“化工分离过程”课程教学

讨论了国内外化工分离过程课程改革的趋势,认为化工分离过程的课程内容正在不断拓宽、更加重视“原理”的讲授、采用计算机模拟技术更新教学内容是大势所趋、势在必行。文中最后给出了采用CHEMCAD软件更新化工分离过程教学内容的初步方案。     

化工原理教学中的核心概念:传递的平衡态与过程的推动力

热力学平衡、过程推动力是化工原理课程中的两个核心概念,对于理解传递过程非常重要。文章围绕这两个概念,基于单元操作的特性与物理定律,建立相应的平衡线方程,从理论上明确传递的极限(终点);进一步依据传递方程的基本表达式,用图示法对传递过程的推动力进行具体描述,强调推动力在传递动力学中的核心作用,从工程实际角度加深学生对化工传递过程的理解。     

Simulation and validation of ethanol removal from water in an adsorption packed bed: Isotherm and mass transfer parameter determination in batch studies

Preferential adsorption of ethanol from ethanol/water mixtures in batch equilibrium and kinetic experiments were carried out on a commercially available activated carbon adsorbent Filtrasorb 600 (F‐600). A model based on finite difference method was developed and employed to determine the mass transfer parameters and equilibrium behaviour for the adsorption of ethanol from simple batch systems. The estimates of the adsorption isotherm along with the mass transfer parameters were used to simulate the transient performance that could be expected in a packed bed under various operating conditions (feed flow rate, feed concentration, and particle size). The applicability of the simulation results were found to be a good match with experimental packed bed experiments over the entire range of operating conditions tested.     

超临界流体技术在农药研究中的应用

超临界流体(supercriticalfluid,SCF)技术具有许多优越特性,已经广泛用于农药活性物质提取、农药残留分析、残留农药消除等领域。随着其理论和技术的深入发展,超临界流体成核、超临界流体反应、超临界流体拆分等多种高效、经济新技术将大量应用于农药研究,并成为推动农药领域深入发展的有力工具。附参考文献68篇。     

化学工程视野下的电化学能源转换与存储

以风力/太阳能等为代表的间歇性可再生能源发电技术为能源快速发展注入了新的活力和契机。为此,发展这些电能的高效转换与存储体系至关重要,已成为当今世界范围内的重大挑战性课题之一。基于此,本文讨论和展望了化学工程视野下的电化学能源转换与存储技术的未来发展方向,为解决该领域工业化发展中的关键科学和技术问题提供了有效指导,将全面促进电化学能源转换与存储领域的快速发展。文章从化学工程的视角综述了电化学能源转换与存储技术（二次电池、超级电容器、电化学催化等）的国内外研究发展状况,指出并剖析了该体系存在的关键科学/技术问题,主要内容包括电化学能源转换与存储领域中的三传一反、系统工程、分离工程以及绿色节能新策略等。     

An engineering analysis of transient laminar flows in long microchannels

An engineering model of a transient laminar flow from a pressurised vessel through a long microchannel under a condition of a rapid valve opening at a channel outlet is developed. A valve at the channel outlet, which is opening with a given speed, is modelled as a time‐dependent boundary condition. Transient flows are investigated numerically by the method of characteristics. The calculations show that variations of pressure and velocity distributions along the channel over time, caused by a transient flow regime, decrease with a decrease in the channel diameter and the channel length, an increase in the time of valve opening and an increase in the fluid viscosity. © 2012 Canadian Society for Chemical Engineering     

Influence of the boundary conditions on capillary flow dynamics and liquid distribution in a porous medium

After depositing a wetting liquid onto a porous medium surface, and under the influence of the capillary pressure, the liquid is imbibed into the porous medium creating a wetted imprint. The flow within the porous medium does not cease once all the liquid is imbibed but continues as a secondary capillary flow, where the liquid flows from large pores into small pores along the liquid interface. The flow is solved using the capillary network model, and the influence of the boundary condition on the liquid distribution within the porous medium is investigated. The pores at the porous medium boundaries can be defined as open or closed pores, where an open pore is checked for the potential threshold condition for flow to take place. In contrast, the closed pore is defined as a static entity, in which the potential condition for flow to take place is never satisfied. By defining the pores at distinct porous medium boundaries as open or closed, one is able to obtain a very different liquid distribution within the porous medium. The liquid saturation profiles along the principal flow direction, ranging from constant to steadily decreasing, to the profile with a local maximum, are found numerically. It is shown that these saturation profiles are also related to the geometrical dimension that is perpendicular to the flow principal direction, and changing the boundary type from open to closed allows the liquid distribution within the porous medium to be controlled. In addition to the liquid distribution, the influence of the boundary conditions on capillary pressure and relative permeability is investigated, where both parameters are not influenced by variation of the boundary condition types. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Experimental study of the role of the Weber and capillary numbers on Mesler entrainment

Mesler entrainment is the formation of a very large number of very small bubbles by a relatively low velocity drop impacting a liquid surface. The role of the Weber number in Mesler entrainment has received significant attention. However, the effect of the capillary number, which quantifies the relative importance of viscous and surface tension forces, has not been explored. This is due primarily to the fact that virtually all Mesler entrainment research has used a single liquid, water, as the working fluid. This, combined with certain experimental restrictions, makes difficult an independent variation of the Weber and capillary numbers. To address this problem, Mesler entrainment was investigated using two silicone oils, having kinematic viscosities of 0.65 cSt and 10.0 cSt, respectively, revealing the effect of the capillary number on Mesler entrainment, a result which has not been obtained heretofore. The silicone oils give extremely repeatable results when compared to water. © 2012 American Institute of Chemical Engineers AIChE J, 2012     

The importance of gravity in droplet evaporation: A comparison of pendant and sessile drop evaporation with particles

As a droplet with particles evaporates, the particles deposit on the substrate surface. In this work, we show the extent of gravitational effects on the particle deposition profile and propose a new model for particle tracing in an evaporating droplet which accounts for gravitational effects. Experimentally, we compare pendant and sessile water droplets with 1 and 3 μm polystyrene particles. Numerically, the finite element method was used to create a transport model of the evaporating droplet system and particle deposition. The numerical and experimental results have excellent agreement and show that a pendant water droplet with 1 and 3 μm polystyrene spheres has significant separation of the two particle sizes. Finally, a phase diagaram was created to map different deposition profiles for various gravitational Péclet numbers (Pe_G) and ratios of Péclet number to Damköhler number (Pe/Da). © 2015 American Institute of Chemical Engineers AIChE J, 62: 947–955, 2016     

Drag reduction in turbulent pipeline flow of mixed nonionic polymer and cationic surfactant systems

Turbulent drag reduction behaviour of a mixed nonionic polymer/cationic surfactant system was studied in a pipeline flow loop to explore the synergistic effects of polymeric and surfactant drag reducing additives. The nonionic polymer used was polyethylene oxide (PEO) at three different concentrations (500, 1000, and 2000 ppm). The surfactant used was cationic octadecyltrimethylammonium chloride (OTAC) at concentration levels of 1000 and 2500 ppm. Sodium salicylate (NaSal) was used as a counter‐ion for the surfactant at a molar ratio of 2 (MR = Salt/OTAC = 2). Relative viscosity and surface tension were measured for different combinations of PEO and OTAC. While the relative viscosities demonstrated a week interaction between the polymer and the surfactant, the surface tension measurements exhibited negligible interaction. The pipeline results show a considerable synergistic effect, that is, the mixed polymer–surfactant system gives a significantly higher drag reduction (lower friction factors) as compared with pure polymer or pure surfactant. The addition of surfactant to the polymer always enhances drag reduction. However, the synergistic effect in mixed system is stronger at low polymer concentrations and high surfactant concentrations. © 2011 Canadian Society for Chemical Engineering     

气液等离子体过程强化技术及其在高级氧化过程的应用

气液等离子体过程强化技术是20世纪80年代发展起来的一门新兴交叉学科,在高级氧化过程、液相化学合成和纳米材料制备等领域具有巨大的研究与应用价值。从化学工程的角度理解,气液等离子体过程强化技术的本质是特殊外场作用下的多相传递与反应过程,其中涉及高能电子碰撞、化学活性组分氧化、紫外光解和冲击波等多种物理与化学作用。由于气液等离子体过程强化技术本身的复杂性及多学科交叉性,对其复杂的物理与化学耦合机理还未得到充分认识,同时缺乏对气液等离子体反应器的系统研究及设计指导,从而极大程度地限制了该技术的进一步应用和发展。为全面认识气液等离子体过程强化技术,本文综述了近年来有关气液等离子体过程强化技术的诊断及机理研究进展,并剖析了气液等离子体反应器的设计思路,同时回顾和展望了气液等离子体高级氧化过程的最新研究进展,讨论了气液等离子体过程强化技术的研究方向。