微混合技术研究进展

在微尺度混合下,传递和反应性能得到明显改善;微混合器易与微反应系统集成,使化学反应更为可控,效率更高。综述了微混合技术的发展和研究现状,探讨了微混合技术的特点和优势及其在反应过程中的应用前景。     

微型化工设备的研究与应用进展

微型化、集成化是未来科学技术的发展方向,在微化工过程中,微型化工设备的开发和应用为微化工的实现提供了强大的支持。按用途将微型化工设备分为微热交换器、微反应器、微分离器、微混合器等,分别对其特点和研究应用现状进行简单的介绍,并对其前景进行展望,同时指出了未来发展可能会遇到的难题。     

微反应器发展概况

微反应器和微混合器作为实现高效混合的最重要的手段之一被越来越多的科技工作者和商业领域青睐。介绍了微反应器的概念、特点和种类;从其几何特征出发阐述了微反应器内微混合机理。简略介绍了微反应器具有的独特优越性。总结了近年来国内外微反应器的研究发展情况和存在的问题。     

微/纳反应器的研究现状及发展前景

微化工系统已经成为解决许多高新技术领域的化工过程问题的关键,而微反应器作为微化工系统的核心已经成为研究的热点之一。本文着重分析了微反应器的概念、分类及其性能优势,总结出近年来国内外微反应器的研究发展情况和存在的问题,并对发展前景进行了展望。     

微化学工程中的微反应技术

微化学工程包括微型单元操作设备,如微型构造的传质、传热、混合、分离和反应设备等、微型传感技术,以及利用微型构造设备进行化学化工研究和生产的微化学工艺体系,其中微反应技术代表了新的化学加工途径,本文重点介绍了微反应技术的概念和一些研究应用实例。     

微反应器技术在精细化工中的应用

近年来,微反应器技术已逐渐成为国际精细化工技术领域的研究热点。该文介绍了微反应器技术的最新研究进展;通过分析微反应器的内在结构特征,阐明了微反应器技术的特殊优势;分析了微反应器适合的化学反应类型;列举了大量微反应器技术应用的成功范例;通过微反应器技术和常规反应器技术的比较,说明了微反应器技术在精细化工领域的巨大价值和动人前景。     

微反应器研究最新进展

微化工系统是实现化工过程绿色、安全、高效的重要方法,微反应器作为微化工系统的核心已经成为科学研究的热点之一.近年来,随着微尺度下"三传一反"研究的进展,微尺度流体的性能得到了深入揭示,微反应器技术也被广泛应用于科学研究和工业生产领域.本文以液相微反应器性能和应用为中心,重点讨论微反应器研究的最新进展.     

我国在化工、生物与热动力微系统领域的研究进展

简述了我国在化工、生物与热动力微系统及相关微制造技术的最新研究进展.文中指出由于具有小型化、强化传质、传热的优点,微反应器被广泛应用在化学反应中,这些反应主要包括液相、气相反应和纳米颗粒合成.微反应技术适用于一些高危反应或利用传统方法合成较困难或成本和价值非常高的反应.微流控技术应用于生物分析与测试领域也已经取得了长足...     

微乳液技术研究进展及其在涂料中的应用

阐述了微乳液的形成机理、微观结构、特征以及制备方法,介绍了微乳液聚合理论及几类微乳液在涂料工业中的具体应用,并提出了在实际应用中存在的问题以及解决方法,展望了微乳液的发展趋势。     

微混合技术的原理与应用

介绍了微混合技术的发展现状;以微混合器内的混合机制为主线,探讨了不同的微混合器结构型式及其在微反应系统中的应用;展望了微混合技术的应用前景。     

Simultaneous Absorption of Hydrogen Sulfide and Carbon Dioxide into di-isopropanolamine Solution

The simultaneous absorption of hydrogen sulfide and carbon dioxide into di-isopropanolamine (DIPA) solution was investigated in a 183 cm long, 2.72 cm OD wetted-wall column at atmospheric pressure. The influence of liquid flow rate, gas flow rate, temperature and liquid concentration on the absorption rate, overall gas-phase mass transfer coefficient and selectivity factor were studied at a constant gas feed ratio. The results show that the absorption rate of CO₂ increases rapidly with increasing liquid flow rate (the Reynolds number of the turbulent liquid film ranges from 2600 to 4350) but increases moderately with increasing gas flow rate (G = 18-91 L/min), indicating that it is liquid-phase mass transfer controlled. In contrast, the absorption rate of H₂S increases very slowly with increasing liquid flow rate but increases rapidly with increasing gas flow rate, indicating that it is gas-phase mass transfer controlled. The absorption rate of CO₂ also increases with increasing temperature (26-80°C) but H₂S absorption rate decreases with increasing temperature. When the concentration of DIPA solution increases from 0.2 to 2.6 mol/L, the absorption rate of both CO₂ and H₂S increases but with a larger rate of increase for CO₂ For selective H₂S removal, it is preferable to operate at low liquid and high gas flow rates, low temperatures and low DIPA concentrations.     

传质对热天平坩埚内煤焦气化反应的影响

热天平标准配置的坩埚为四周及底部密封的敞口容器,气流不能穿过物料层从坩埚底部流出,从而影响煤焦气化反应的动力学行为.研究了坩埚尺寸、物料床层厚度对杯状坩埚内煤焦-CO₂气化（气固相反应）影响.采用PHOENICS软件模拟分析了杯状坩埚附近及内部流体运动、浓度分布,同时建立了杯状坩埚内煤焦-CO₂反应-扩散模型,两者能很好地吻合.杯状坩埚中进行的煤焦-CO₂反应模型参数φ和D_a反映了气体质量传递对反应的影响.     

填料塔中碳酸钾/哌嗪混合吸收液脱除CO2的体积传质系数

The process of removing dilute CO2 from air by using me mixtures of K2CO3 and piperazine (PZ) was conducted in a random packed tower at 25℃. The results showed that PZ increased the absorption rate of CO2 into aqueous K2 CO3 much more effectively than MEA or DEA. The volumetric overall mass transfer coefficient (KGa) of dilute CO2 absorption into K2CO3/PZ was measured. The KGa value was evaluated over the ranges of main operating variables: the concentration of CO2 in inlet gas, gas flow rate, liquid loading, CO2 loading in liquid phase, and the concentrations of K2CO3 and PZ. The test showed that KGa could be remarkably improved by increasing liquid loading and the concentration of PZ, and decreasing the concentration of CO2 in inlet gas, as well as the gas flow rate and CO2 loading in liquid phase.     

Carbon Dioxide Mass Transfer into Solvents in a Zeolite Hybrid Device

Carbon dioxide (CO₂) mass transfer processes are analyzed in hybrid equipment which involves a zeolitic membrane and a physical or chemical solvent. This separation device was chosen because the membrane can be used to produce a stream of higher CO₂ concentration to be treated by gas‐liquid absorption. The analysis of the mass transfer behavior of this gas through the solid phase is an important step before more complicated gas streams are applied. The combined use of both techniques can improve the global separation process because they allow performing a previous separation with a positive effect on the cost of the later separation operations. The influence of the liquid phase nature used in one chamber of the membrane contactor upon CO₂ global mass transfer is analyzed. Also the effect caused by the absorption regime, liquid and gas flow rates, and the pressure corresponding to the gas chamber on CO₂ mass transfer is studied to evaluate the importance of each variable.     

中空纤维膜吸收器中CO2吸收过程模拟

研究了CO₂在中空纤维膜吸收器中的吸收过程.以非湿膜操作为例，建立了中空纤维膜吸收器的传质模型，用T-型差分法模拟了CO₂在水、NaOH、乙醇胺(MEA)、2-胺基-2-甲基-1-丙醇(AMP)水溶液中的吸收.研究了AMP-MEA混合有机胺水溶液吸收CO₂的过程.对于CO2在0.6mol•L^-1 NaOH水溶液中的吸收，比较了模拟结果与实验数据，二者符合较好.     

Gas-side mass transfer coefficients in a falling film microreactor

Gas–liquid mass transfer in a falling film microreactor (FFMR) with 29 microchannels (0.6 mm width each) was investigated. CO₂ was absorbed from a CO₂/N₂ gaseous mixture into a NaOH aqueous solution and the liquid-side mass transfer coefficient and the gas-side mass transfer coefficient were measured. The influence of gas concentration on the value of gas-side mass transfer coefficient has been discussed.     

Effects of gas concentration on hydrodynamics of gas absorption in a microchannel

In this article, the effects of gas concentration on hydrodynamics of gas–liquid two-phase flow with mass transfer during gas absorption in a microchannel are investigated, by using 2-amino-2-methyl-1-propanol (AMP) solution to absorb mixtures of CO₂ and N₂ with various volume fractions. The concentration of CO₂ not only affects the driving force of gas–liquid mass transfer, but also affects the pressure drop of gas–liquid two-phase flow. The average linear velocity of the liquid phase is estimated by introducing the void fraction, which accurately characterizes the difference in the bubble velocity versus the liquid velocity. On this basis, the pressure drop model of gas–liquid two-phase flow with mass transfer in a microchannel is established. Through the pressure drop model, the influence mechanism of CO₂ concentration on the pressure drop during gas absorption in a microchannel is revealed.     

微通道内气-液传质研究

以CO₂-H₂O为模型体系，实验考察了当量直径为667 μm的单通道和16个并行通道内的气-液传质行为.实验发现，液体表观速度增加，单通道内液侧体积传质系数明显提高;同一液体表观速度下，液侧体积传质系数随气体表观速度增加而增加;在实验数据基础上关联了液侧体积传质系数与气-液两相流参数间的关系.微通道内的液侧体积传质系数较常规尺度气-液接触设备至少高1～2个数量级.并讨论了并行微通道内气-液两相流分配特性对整体传质性能的影响，表明合理设计气、液流动分布结构，可保证微通道内优异的传质特性.     

Removal of CO2 and/or SO2 from gas streams by a membrane absorption method

Studies were made on the membrane absorption of CO₂ and/or SO₂ using hydrophobic microporous hollow-fibre (HF) membrane modules. The absorbent liquids used were aqueous solutions of NaOH, K₂CO₃, alkanolamines and Na₂SO₃, flowing on the lumen side of the HF in laminar flow. A semi-empirical correlation was derived for the gas-phase mass-transfer coefficient on the shell side, by including geometrical factors of the HFs and the shell tube in the general correlation for mass transfer. It was found that the CO₂ absorption rate in various aqueous solutions of alkalis and alkanolamines is successfully described by a model based on gas diffusion through the membrane pores subsequent to gas absorption accompanied by chemical reaction. The simultaneous membrane absorption of SO₂ and CO₂ was also studied using aqueous Na₂SO₃ solution, the selective removal of SO₂ to CO₂ being successfully achieved when both the liquid flow rate and solute concentration are low. This suggests that this membrane absorption method provides an energy saving process for SO₂ removal from flue gases.     

氨基酸离子液体-MDEA混合水溶液的CO2吸收性能

为改善N-甲基二乙醇胺(MDEA)水溶液对CO₂气体的吸收性能,选择了四甲基铵甘氨酸(［N₁₁₁₁］［Gly］)、四乙基铵甘氨酸(［N₂₂₂₂］［Gly］)、四甲基铵赖氨酸(［N₁₁₁₁］［Lys］)、四乙基铵赖氨酸(［N₂₂₂₂］［Lys］)4种功能性离子液体作为活化剂与其复配组成新型CO₂吸收剂。用恒定容积法考察了总质量分数为30%的混合溶液吸收CO₂的性能,分析了离子液体在水溶液中与MDEA通过质子传递相互促进吸收CO₂的机理。实验结果显示离子液体能够显著提高MDEA水溶液吸收CO₂的速率,且吸收速率随着添加量的增加而提高。在本文所用的几种混合吸收剂中,阴离子为赖氨酸的离子液体混合吸收剂具有较高的吸收负荷;而［N₁₁₁₁］［Gly］-MDEA混合溶液对CO₂的初期吸收速率最快,同时［N_1111^］［Gly］-MDEA混合吸收剂的再生效率高于其他离子液体混合吸收剂,达到98%。