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1.
Yi Ouyang Manuel Nunez Manzano Siyuan Chen Ruben Wetzels Tom Verspeelt Kevin M. Van Geem Geraldine J. Heynderickx 《American Institute of Chemical Engineers》2022,68(5):e17608
To develop cost-effective CO2 capture technology process intensification will play a vital role. In this work, the capabilities of a gas–liquid vortex reactor (GLVR) as novel process intensification equipment are evaluated by studying its interphase mass transfer parameters to build up the fundamentals for its future application to for example, CO2 capture. The NaOH-CO2 chemisorption system and Danckwerts' model are applied to obtain the effective interfacial area and liquid-side mass transfer coefficient. Results show that the gas–liquid contact in the GLVR is capable of both generating a large interfacial area in a small reactor volume and creating a region with high-energy dissipation to improve mass transfer. A comparison of the volumetric mass transfer coefficients with data reported in literature for conventional and intensified reactor types confirms a superior mass transfer efficiency and, most importantly, a favorable energetic efficiency of the GLVR. 相似文献
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Yi Ouyang Manuel Nunez Manzano Koenraad Beirnaert Geraldine J. Heynderickx Kevin M. Van Geem 《American Institute of Chemical Engineers》2021,67(7):e17264
The gas–liquid vortex reactor (GLVR) has substantial process intensification potential for multiphase processes. Essential in this respect is the micromixing efficiency, which is of great importance in fast reaction systems such as crystallization, polymerization, and synthesis of nanomaterials. By creating a vortex flow and taking advantage of the centrifugal force field, the liquid micromixing process can be intensified in the GLVR. Results show that introducing a liquid into a gas-only vortex unit results in suppression of primary and secondary gas flow. The Villermaux–Dushman protocol is applied to study the effects of the gas flow rate, liquid flow rate, and liquid viscosity based on a segregation index. Based on the incorporation model and reaction kinetics, the micromixing time of the GLVR is determined to be in the range of 10−4 ~ 10−3 s, which is comparable to the highly efficient rotating packed bed and substantially better than a static mixer. 相似文献
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Baldassarre Venezia David C. Morris Asterios Gavriilidis 《American Institute of Chemical Engineers》2023,69(3):e17880
A unique Taylor-vortex membrane reactor (TVMR) design for continuous gas-liquid reactions is presented in this work. The reactor consists of a cylindrical rotor inside a stationary concentric cylindrical vessel, and a flexible system of equispaced baffle rings surrounding the rotor. This restricts the annular cross section to a small gap between the baffles and the rotor, and divides the annulus into 18 mixing zones. The baffles support a 6 m long PFA tubular membrane that is woven around the rotor. At 4 mL/min inlet flow rate, the TVMR showed a plug-flow behavior and outperformed the unbaffled reactor, having 5–12 times lower axial dispersion. The continuous aerobic oxidation of benzyl alcohol was performed for 7 h using the Pd(OAc)2/pyridine catalyst in toluene at 100 °C and 1.1 MPa oxygen pressure. A stable conversion of 30% was achieved with 85% benzaldehyde selectivity, and no pervaporation of organics into the gas phase. 相似文献
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流化床反应器过程强化技术 总被引:2,自引:0,他引:2
张维 《中国化学工程学报》2009,17(4):688-702
Fluidized beds enable good solids mixing, high rates of heat and mass transfer, and large throughputs, but there remain issues related to fluidization quality and scale-up. In this work I review modification techniques for fluidized beds from the perspective of the principles of process intensification (PI), that is, effective bubbling sup-pression and elutriation control. These techniques are further refined into (1) design factors, e.g. modifying the bed configuration, or the application of internal and external forces, and (2) operational factors, including altering the particle properties (e.g. size, density, surface area) and fluidizing gas properties (e.g. density, viscosity, or velocity). As far as two proposed PI principles are concerned, our review suggests that it ought to be possible to gain improve-ments of between 2 and 4 times over conventional fluidized bed designs by the application of these techniques. 相似文献
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Peng Yan Xingang Li Hong Li Yuanyuan Shao Hui Zhang Xin Gao 《American Institute of Chemical Engineers》2020,66(1):e16793
Interfacial wettability adjustment is a new method for intensifying vapor–liquid mass transfer process. Contact angle effect has been well investigated but not complete due to interfacial wettability consisting of both static behavior (contact angle) and dynamic behavior (contact angle hysteresis). Here, methods of adjusting contact angle hysteresis (CAH) were proposed, and then, the CAH effect on the hydrodynamics was investigated. A multiscale analysis of CAH effect, from interfacial force and wettability to single-bubble and gas–liquid two-phase flow inside the foam to bubble swarm hydrodynamics, was conducted, and thus, the hydrodynamic performance criteria were derived. The interfaces had similar contact angles, whereas a significant difference in the CAH was prepared by using the developed sol dip-coating and spray coating methods. Subsequent experiments revealed that lower CAH can decrease the pressure drop, homogenize the gas distribution, and increase the weeping rate, which are consistent with the derived criteria. 相似文献
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Fatemeh Gholami;Salman Movahedirad;Mohammad Amin Sobati;Mojtaba Babaei; 《加拿大化工杂志》2024,102(1):177-195
In the present study, the hydrodynamic behaviour of a three-dimensional bubbling fluidized bed reactor was studied using the finite volume method and granular kinetic theory. The effect of two types of gas distributors (i.e., perforated and porous plates) on the gas/solid hydrodynamic was investigated. The residence time distribution model was utilized to check the deviation of the gas flow pattern from the ideal flow patterns for two types of distributors. The parameters indicating the degree of back-mixing, such as mean residence time and dimensionless variance, were calculated. Also, the model was verified through the comparison of the particle velocity with experimental data obtained by the particle image velocimetry–digital image processing (PIV-DIA) technique. It was found that the gas flow pattern in the present bubbling fluidized bed is closer to the mixed flow than the plug flow pattern. It was also found that the porous plate distributor gives more uniform hydrodynamic distributions of gas and solid in the bed, which results in better gas–solid mixing due to the formation of the smaller bubbles. 相似文献
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Zhenyu Wu Jinjin Cai Dimiao Wang Xiaojiang Liang Qinglong Xie Yong Nie Jianbing Ji 《American Institute of Chemical Engineers》2021,67(11):e17370
A packed bed reactor with orifice plates (PBR@OP) was designed by adding orifice plates periodically in packed beds. Hydrodynamics and droplet size distribution in PBR@OP were experimentally investigated using fatty acid methyl esters (FAME)/water as the model liquid–liquid system. In PBR@OP, the flow pattern was close to plug flow. Droplets with Sauter mean diameter (d32) of 150–550 μm were generated. The pressure drop of orifice, flow velocity and plate spacing were key parameters to control the droplet size. The reactor performance was evaluated by analyzing a FAME epoxidation process. At the same d32 and residence time, the length and total pressure drop of PBR@OP were about 1/3 and 1/4 of those of PBR without orifice plates, respectively. Furthermore, a semi-empirical correlation describing the d32 change in PBR@OP was developed, revealing a relative mean deviation of 8.64%. PBR@OP presents a cost-effective option for the intensification of liquid–liquid medium rate reactions. 相似文献
8.
Amir Mowla Mehrez Agnaou Tanyakarn Treeratanaphitak Hector M. Budman Nasser M. Abukhdeir Marios A. Ioannidis 《American Institute of Chemical Engineers》2020,66(6):e16959
We quantify the ability of the two-fluid Euler–Euler model to predict the overall gas hold-up during two-phase flow in vertical columns using a combination of experiments and simulations. Gas hold-up in a bubble column and gas hold-up in the less-frequently studied co-current flow are investigated. For homogeneous flow characterized by nearly uniform bubble size, Euler–Euler model predictions are within 10% of the experimental values for both modes of operation, if the bubble diameter supplied as input to the model is the average bubble diameter in the physical system. This also holds true for heterogeneous flow in bubble columns despite the presence of a broad distribution of bubble sizes, if turbulence and bubble swarm effects on momentum exchange between phases are properly accounted for. Swarm corrections adequate for bubble columns, are less successful for co-current heterogeneous flow, for which gas hold-up predictions are least accurate (average error of 22%). 相似文献
9.
Maria N. Pantzali Jelena Z. Kovacevic Geraldine J. Heynderickx Guy B. Marin Vladimir N. Shtern 《American Institute of Chemical Engineers》2015,61(12):4114-4125
A unique normalized radial pressure profile characterizes the bed of a gas‐solid vortex reactor over a range of particle densities and sizes, solid capacities, and gas flow rates: 950–1240 kg/m3, 1–2 mm, 2 kg to maximum solids capacity, and 0.4–0.8 Nm3/s (corresponding to gas injection velocities of 55–110 m/s), respectively. The combined momentum conservation equations of both gas and solid phases predict this pressure profile when accounting for the corresponding measured particle velocities. The pressure profiles for a given type of particles and a given solids loading but for different gas injection velocities merge into a single curve when normalizing the pressures with the pressure value downstream of the bed. The normalized—with respect to the overall pressure drop—pressure profiles for different gas injection velocities in particle‐free flow merge in a unique profile. © 2015 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 61: 4114–4125, 2015 相似文献
10.
ABSTRACTThis work studied the gas–liquid–liquid (G–L–L) reaction system of CO2 absorption into K2CO3/KHCO3 buffer solution enhanced by organic phase in a rotor–stator reactor (RSR). The effects of volume fraction of organic phase, type of organic phase, rotational speed of RSR, gas and liquid volumetric flow rate, and temperature on CO2 absorption percentage were investigated. Results indicate that the addition of the organic phase with a volume fraction of 1.3–1.6% had significant promoting effect on CO2 absorption. CO2 absorption percentage increased with increase in the rotational speed of the RSR but decreased with rise in liquid temperature and gas–liquid ratio. This work demonstrates that RSR can significantly enhance liquid–liquid mixing and gas–liquid mass transfer processes in the G–L–L system. 相似文献
11.
Wei Liu Bingqi Xie Chenghao Zhang Xiaonan Duan Jisong Zhang 《American Institute of Chemical Engineers》2023,69(7):e18004
Micro-packed bed reactors (μPBRs) have the advantages of high heat and mass transfer efficiency and excellent safety, and they have been successfully applied to hydrogenation and oxidation reactions. However, the study of gas–liquid flow regimes in the μPBR, which is essential for the mass transfer modeling and reactor scale-up, is still insufficient due to the limitation of micro-scale and complexity of capillary force. In this work, the flow regimes in the two-dimensional μPBR were systematically studied by visual method utilizing a high-performance camera. Four typical flow regimes and characteristics were captured, and flow regime transition was revealed. Effects of gas and liquid superficial velocities, liquid physical properties, and particle sizes on liquid spreading areal fraction and pressure drop were investigated. Flow regime transition correlation of churn flow and pseudo-static flow in the μPBR was provided for the first time based on the summary of the current and previous published results. 相似文献
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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。 相似文献
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为了强化釜式氢化锂(LiH)合成反应器,采用计算流体力学(CFD)方法模拟了该坩埚反应器在静态操作、机械搅拌和气体鼓泡三种情况下的物质传递、化学反应和流体运动规律。模拟结果表明:自然对流对反应有较大的促进作用,其使LiH脱离反应界面,保证界面处"新鲜"金属Li与氢气的有效接触;另外,自然对流也促使反应器内物料良好混合;机械搅拌虽提高了反应物料的混合状况,但并不显著增加反应界面,过程强化程度有限;气体鼓泡可大幅度增加气液接触面积,反应时间大幅度缩减,是一种优选的LiH合成反应器构型。 相似文献
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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。 相似文献
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Novel operability‐based approach for process design and intensification: Application to a membrane reactor for direct methane aromatization
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This article introduces a novel operability‐based approach for process design and intensification of energy systems described by nonlinear models. This approach is applied to a membrane reactor (MR) for the direct methane aromatization (DMA) conversion to benzene and hydrogen. The proposed method broadens the scope of the traditional path of the operability approaches for design and control, mainly oriented to obtain the achievable output set (AOS) from the available input set, and compare the computed AOS to a desired output set. In particular, an optimization algorithm based on nonlinear programming tools is formulated for the calculation of the desired input set that is feasible considering process constraints and intensification targets. Results on the application of the operability method as a tool for process intensification show reduction of the DMA‐MR footprint (≈77% reactor volume and 80% membrane area reduction) for an equivalent level of performance, when compared to the base case. This case study indicates that the novel approach can be a powerful tool for process intensification of membrane reactors and other complex chemical processes. © 2016 American Institute of Chemical Engineers AIChE J, 63: 975–983, 2017 相似文献
19.
Investigation of the collapse of bubbles after the impact of a piston on a liquid free surface
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Maya Mounir Daou Elena Igualada Hugo Dutilleul Jean‐Marie Citerne Javier Rodríguez‐Rodríguez Stéphane Zaleski Daniel Fuster 《American Institute of Chemical Engineers》2017,63(6):2483-2495
A novel technique based on the impact of a piston on a liquid confined in a vessel is described. Pressure measurements reveal that strong pressure variations (up to 100 atmospheres) with a rich content of frequencies are efficiently transmitted to the liquid. High‐speed camera visualizations show that pre‐existing millimetric bubbles always collapse during the first instants of the impact whereas the behavior of submillimetric bubbles depends on the features of the pressure evolution in the system. In addition to the impact velocity, the amount of gas/vapor trapped between the piston and the liquid's surface plays an important role on how pressure evolves. Only when negative pressure occurs tiny bubbles grow significantly and collapse. The violent collapse of bubbles promote turbulence and mixing at very small length‐scales which renders this technique interesting to intensify processes limited by heat and mass diffusion. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2483–2495, 2017 相似文献
20.
Zhiqian Jia Zhongzhou Liu 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2013,88(2):163-168
For homogeneous liquid processes, mixing at molecular scale may influence selectivity, yield and quality of final products. In a membrane‐dispersion reactor, microporous membranes are employed as dispersion media for controlled feeding of one solution into another one to intensify micromixing. The reactor has been widely used in the preparation of nanoparticles, preparation of nanocapsules and liposomes, synthesis of polymers, parallel and consecutive reactions to improve nanoparticles quality, molecular weight distribution of polymer, or selectivity of complex reactions. This paper reviewed the progress of the membrane‐dispersion reactor in homogeneous liquid processing including features, applications, advantages and limits. © 2012 Society of Chemical Industry . 相似文献