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Multiphase surfactant-assisted reaction-separation system in a microchannel reactor

Salah ALJBOUR, Tomohiko TAGAWA, Mohammad MATOUQ, Hiroshi YAMADA

《化学科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 33-38 doi: 10.1007/s11705-009-0108-6

摘要: The Lewis acid-catalyzed addition of trimethylsilyl cyanide to -chlorobenzaldehyde in a microchannel reactor was investigated. The microchannel was integrated to promote both reaction and separation of the biphase system. FeF and Cu(triflate) were used as water-stable Lewis acid catalysts. Sodium dodecyl sulfate was incorporated in the organic-aqueous system to enhance the reactivity and to manipulate the multiphase flow inside the microchannel. It was found that the dynamics and the kinetics of the multiphase reaction were affected by the new micellar system. Parallel multiphase flow inside the microchannel was obtained, allowing for continuous and acceptable phase separation. Enhanced selectivity was achieved by operating at lower conversion values.

关键词: Lewis acid catalysis     multiphase reactions     process intensification     microchannel reactor     green engineering    

Sustainable functionalization and modification of materials via multicomponent reactions in water

《化学科学与工程前沿(英文)》 2022年 第16卷 第9期   页码 1318-1344 doi: 10.1007/s11705-022-2150-6

摘要: In materials chemistry, green chemistry has established firm ground providing essential design criteria to develop advanced tools for efficient functionalization and modification of materials. Particularly, the combination of multicomponent reactions in water and aqueous media with materials chemistry unlocks a new sustainable way for constructing multi-functionalized structures with unique features, playing significant roles in the plethora of applications. Multicomponent reactions have received significant consideration from the community of material chemistry because of their great efficiency, simple operations, intrinsic molecular diversity, and an atom and a pot economy. Also, by rational design of multicomponent reactions in water and aqueous media, the performance of some multicomponent reactions could be enhanced by the contributing “natural” form of water-soluble materials, the exclusive solvating features of water, and simple separating and recovering materials. To date, there is no exclusive review to report the sustainable functionalization and modification of materials in water. This critical review highlights the utility of various kinds of multicomponent reactions in water and aqueous media as green methods for functionalization and modification of siliceous, magnetic, and carbonaceous materials, oligosaccharides, polysaccharides, peptides, proteins, and synthetic polymers. The detailed discussion of synthetic procedures, properties, and related applicability of each functionalized/modified material is fully deliberated in this review.

关键词: materials     multicomponent reactions     modification     functionalization     water    

Extended two-fluid model applied to analysis of bubbly flow in multiphase rotodynamic pump impeller

Zhiyi YU, Guoyu WANG, Shuliang CAO

《机械工程前沿(英文)》 2009年 第4卷 第1期   页码 53-59 doi: 10.1007/s11465-009-0006-0

摘要: This paper presents an extended two-fluid model based on the Navier-Stokes equations and the standard turbulence model, to simulate the three-dimensional air-water bubbly flow in turbo machinery. In the governing equations, the drag force and added mass force are added and the additional source terms arising from fluctuations of gas volume fraction are considered. The discrete equations are solved using a developed two-phase semi-implicit method for pressure-linked equations, consistent (SIMPLEC) algorithm in body-fitted coordinates with a staggered grid system. Simulation is then carried out for the pure liquid flow and air-water two-phase flow with the inlet gas volume fraction being 15% in a multiphase rotodynamic pump impeller and the pump head performance is predicted. Comparison with experimental results shows the reliability and commonality of the numerical model.

关键词: two-fluid model     multiphase rotodynamic pump     SIMPLEC algorithm     numerical simulation    

Application of different CFD multiphase models to investigate effects of baffles and nanoparticles on

Ali SHAHMOHAMMADI,Arezou JAFARI

《化学科学与工程前沿(英文)》 2014年 第8卷 第3期   页码 320-329 doi: 10.1007/s11705-014-1437-7

摘要: In this work, the effect of baffles in a pipe on heat transfer enhancement was studied using computational fluid dynamics (CFD) in the presence of Al O nanoparticles which are dispersed into water. Fluid flow through the horizontal tube with uniform heat flux was simulated numerically and three dimensional governing partial differential equations were solved. To find an accurate model for CFD simulations, the results obtained by the single phase were compared with those obtained by three different multiphase models including Eulerian, mixture and volume of fluid (VOF) at Reynolds numbers in range of 600 to 3000, and two different nanoparticle concentrations (1% and 1.6%). It was found that multiphase models could better predict the heat transfer in nanofluids. The effect of baffles on heat transfer of nanofluid flow was also investigated through a baffled geometry. The numerical results show that at Reynolds numbers in the range of 600 to 2100, the heat transfer of nanofluid flowing in the geometry without baffle is greater than that of water flowing through a tube with baffle, whereas the difference between these effects (nanofluid and baffle) decreases with increasing the Reynolds number. At higher Reynolds numbers (2100–3000) the baffle has a greater effect on heat transfer enhancement than the nanofluid.

关键词: CFD simulation     heat transfer     nanofluid     baffle     single phase model     multiphase model    

Simulating multiphase flow in a two-stage pusher centrifuge using computational fluid dynamics

Chong PANG, Wei TAN, Endian SHA, Yuanqing TAO, Liyan LIU

《化学科学与工程前沿(英文)》 2012年 第6卷 第3期   页码 329-338 doi: 10.1007/s11705-012-1205-5

摘要: The design of two-stage pusher centrifuges have developed rapidly, but a good understanding of the theory behind their practice is a long-standing problem. To better understand centrifugal filter processes, the computational fluid dynamics (CFD) software program FLUENT has been used to model the three-dimensional geometry and to simulate multiphase flows based on Euler-Euler, moving mesh, dynamic mesh and porous media models. The simulation tangential velocities were a little smaller than those for rigid-body motion. In the stable flow region, the radial velocities were in good agreement with the theoretical data. Additionally, solid concentration distribution were obtained and also showed good agreement with the experimental data. These results show that this simulation method could be an effective tool to optimize the design of the two-stage pusher centrifuge.

关键词: two-stage pusher centrifuge     multiphase flow     CFD     dynamic mesh     porous media    

Latest progress in numerical simulations on multiphase flow and thermodynamics in production of natural

Lin ZUO, Lixia SUN, Changfu YOU

《能源前沿(英文)》 2009年 第3卷 第2期   页码 152-159 doi: 10.1007/s11708-009-0017-x

摘要: Natural gas hydrates are promising potential alternative energy resources. Some studies on the multiphase flow and thermodynamics have been conducted to investigate the feasibility of gas production from hydrate dissociation. The methods for natural gas production are analyzed and several models describing the dissociation process are listed and compared. Two prevailing models, one for depressurization and the other for thermal stimulation, are discussed in detail. A comprehensive numerical method considering the multiphase flow and thermodynamics of gas production from various hydrate-bearing reservoirs is required to better understand the dissociation process of natural gas hydrate, which would be of great benefit to its future exploration and exploitation.

关键词: numerical simulation     natural gas hydrate     dissociation     thermodynamics     multiphase flow    

Erosion-corrosion failure of REAC pipes under multiphase flow

Ping TANG, Jian YANG, Jinyang ZHENG, Shizheng HE, Jianjun YE, Guofu OU, Ieong WONG, Yanbao MA,

《能源前沿(英文)》 2009年 第3卷 第4期   页码 389-395 doi: 10.1007/s11708-009-0045-6

摘要: By using computational fluid dynamics (CFD) modeling and simulation, a predictive method was proposed to explore the erosion failure of reactor effluent air cooler (REAC) pipes with liner under multiphase flow. A theoretical model based on the erosion-corrosion effects of REAC on mixture turbulent flow was proposed for multiphase flow. Effects of various working conditions, liner shapes, and structures, as well as flow parameters on numerical simulations were investigated. Besides, the pipe’s erosion-corrosion rules under multiphase flow and the relationship between multiphase flow and erosion-corrosion under dangerous working conditions were studied. By CFD numerical simulations, the exact position where some typical pipes thinned and failed rapidly by erosion was found and the main factors causing erosion-corrosion failure were discussed. Finally, numerical results obtained by using the proposed method were compared with experimental results.

关键词: multiphase flow     erosion-corrosion     pipes     reactor effluent air cooler (REAC)     computational fluid dynamics (CFD)    

Redox reactions of iron and manganese oxides in complex systems

Jianzhi Huang, Huichun Zhang

《环境科学与工程前沿(英文)》 2020年 第14卷 第5期 doi: 10.1007/s11783-020-1255-8

摘要: • Mechanisms of redox reactions of Fe- and Mn-oxides were discussed. • Oxidative reactions of Mn- and Fe-oxides in complex systems were reviewed. • Reductive reaction of Fe(II)/iron oxides in complex systems was examined. • Future research on examining the redox reactivity in complex systems was suggested. Conspectus Redox reactions of Fe- and Mn-oxides play important roles in the fate and transformation of many contaminants in natural environments. Due to experimental and analytical challenges associated with complex environments, there has been a limited understanding of the reaction kinetics and mechanisms in actual environmental systems, and most of the studies so far have only focused on simple model systems. To bridge the gap between simple model systems and complex environmental systems, it is necessary to increase the complexity of model systems and examine both the involved interaction mechanisms and how the interactions affected contaminant transformation. In this Account, we primarily focused on (1) the oxidative reactivity of Mn- and Fe-oxides and (2) the reductive reactivity of Fe(II)/iron oxides in complex model systems toward contaminant degradation. The effects of common metal ions such as Mn2+ , Ca2+, Ni2+, Cr3+ and Cu2+, ligands such as small anionic ligands and natural organic matter (NOM), and second metal oxides such as Al, Si and Ti oxides on the redox reactivity of the systems are briefly summarized.

关键词: Iron oxides     manganese oxides     reduction     oxidation     complex systems     reaction kinetics and mechanisms    

Kinetic Monte Carlo simulations of plasma-surface reactions on heterogeneous surfaces

Daniil Marinov

《化学科学与工程前沿(英文)》 2019年 第13卷 第4期   页码 815-822 doi: 10.1007/s11705-019-1837-9

摘要: Reactions of atoms and molecules on chamber walls in contact with low temperature plasmas are important in various technological applications. Plasma-surface interactions are complex and relatively poorly understood. Experiments performed over the last decade by several groups prove that interactions of reactive species with relevant plasma-facing materials are characterized by distributions of adsorption energy and reactivity. In this paper, we develop a kinetic Monte Carlo (KMC) model that can effectively handle chemical kinetics on such heterogenous surfaces. Using this model, we analyse published adsorption-desorption kinetics of chlorine molecules and recombination of oxygen atoms on rotating substrates as a test case for the KMC model.

关键词: plasma-surface interaction     kinetic Monte Carlo     plasma nano technology    

Numerical simulation and experimental verification of chemical reactions for SCR DeNO

Qiang ZHANG, Yonglin FAN, Wenyan LI

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 523-528 doi: 10.1007/s11705-010-0520-y

摘要: Selective catalytic reduction (SCR) is a major commercial technology for NO removal in power plants. There are a lot of complex chemical reactions in SCR reactors, and it is of great significance to understand the internal process of chemical reactions for SCR DeNO and study the impact of various factors on NO removal efficiency. In this paper, the impact of reaction temperature, ammonia-nitrogen molar ratio and resident time in the catalyst bed layer on NO removal efficiency were studied by simulation of chemical reactions. Then calculated results were compared with catalyst activity test data in a power plant, which proved that the simulated results were accurate. As a result, the reaction conditions were optimized in order to get the best removal efficiency of NO, so that we can provide a reference for optimal running of SCR in power plants.

关键词: SCR     NOx     removal efficiency     chemical reactions     simulation    

Chemical reactions of oily sludge catalyzed by iron oxide under supercritical water gasification condition

《化学科学与工程前沿(英文)》 2022年 第16卷 第6期   页码 886-896 doi: 10.1007/s11705-021-2125-z

摘要: Supercritical water gasification is a promising technology in dealing with the degradation of hazardous waste, such as oily sludge, accompanied by the production of fuel gases. To evaluate the mechanism of Fe2O3 catalyst and the migration pathways of heteroatoms and to investigate the systems during the process, reactive force field molecular dynamics simulations are adopted. In terms of the catalytic mechanisms of Fe2O3, the surface lattice oxygen is consumed by small carbon fragments to produce CO and CO2, improving the catalytic performance of the cluster due to more unsaturated coordination Fe sites exposed. Lattice oxygen combines with •H radicals to form water molecules, improving the catalytic performance. Furthermore, the pathway of asphaltene degradation was revealed at an atomic level, as well as products. Moreover, the adsorption of hydroxyl radical on the S atom caused breakage of the two C–S bonds in turn, forming •HSO intermediate, so that the organic S element was fixed into the inorganic liquid phase. The heteroatom O was removed under the effects of supercritical water. Heavy metal particles presented in the oily sludge, such as iron in association with Fe2O3 catalyst, helped accelerate the degradation of asphaltenes.

关键词: oily sludge     SCWG     ReaxFF     Fe2O3     heteroatoms    

Experimental investigation of multiphase flow behavior in drilling annuli using high speed visualization

Alap Ali ZAHID, Syed Raza ur REHMAN, Anwarul HASAN, S. RUSHD, Mohammad Azizur RAHMAN

《能源前沿(英文)》 2020年 第14卷 第3期   页码 635-643 doi: 10.1007/s11708-018-0582-y

摘要: Imaging with high definition video camera is an important technique to visualize the drilling conditions and to study the physics of complex multiphase flow associated with the hole cleaning process. The main advantage of visualizing multiphase flow in a drilling annulus is that the viewer can easily distinguish fluid phases, flow patterns and thicknesses of cutting beds. In this paper the hole cleaning process which involves the transportation of cuttings through a horizontal annulus was studied. The two-phase (solid-liquid) and the three-phase (solid-liquid-gas) flow conditions involved in this kind of annular transportation were experimentally simulated and images were taken using a high definition camera. Analyzing the captured images, a number of important parameters like velocities of different phases, heights of solid beds and sizes of gas bubbles were determined. Two different techniques based on an image analysis software and MATLAB coding were used for the determinations. The results were compared to validate the image analyzing methodology. The visualization technique developed in this paper has a direct application in investigating the critical conditions required for efficient hole cleaning as well as in optimizing the mud program during both planning and operational phases of drilling. Particularly, it would be useful in predicting the cuttings transport performance, estimating solid bed height, gas bubble size, and mean velocities of bubbles/particles.

关键词: visualization     horizontal annulus     hole cleaning     multiphase flow     image analysis     flow regime    

Research progress on hydrate plugging in multiphase mixed rich-liquid transportation pipelines

Shuyu SONG, Zhiming LIU, Li ZHOU, Liyan SHANG, Yaxin WANG

《能源前沿(英文)》 2022年 第16卷 第5期   页码 774-792 doi: 10.1007/s11708-020-0688-x

摘要: The plugging mechanism of multiphase mixed rich-liquid transportation in submarine pipeline is a prerequisite for maintaining the fluid flow in the pipeline and ensuring safe fluid flow. This paper introduced the common experimental devices used to study multiphase flow, and summarized the plugging progress and mechanism in the liquid-rich system. Besides, it divided the rich-liquid phase system into an oil-based system, a partially dispersed system, and a water-based system according to the different water cuts, and discussed the mechanism of hydrate plugging. Moreover, it summarized the mechanism and the use of anti-agglomerates in different systems. Furthermore, it proposed some suggestions for future research on hydrate plugging. First, in the oil-based system, the effect factors of hydrates are combined with the mechanical properties of hydrate deposit layer, and the hydrate plugging mechanism models at inclined and elbow pipes should be established. Second, the mechanism of oil-water emulsion breaking in partially dispersed system and the reason for the migration of the oil-water interface should be analyzed, and the property of the free water layer on the hydrate plugging process should be quantified. Third, a complete model of the effect of the synergy of liquid bridge force and van der Waals force in the water-based system on the hydrate particle coalescence frequency model is needed, and the coalescence frequency model should be summarized. Next, the dynamic analysis of a multiphase mixed rich-liquid transportation pipeline should be coupled with the process of hydrate coalescence, deposition, and blockage decomposition. Finally, the effects of anti-agglomerates on the morphological evolution of hydrate under different systems and pipeline plugging conditions in different media should be further explored.

关键词: hydrate     rich-liquid phase     plugging mechanism     coalescence     deposition     anti-agglomerate    

Multiphase redistribution differences of polycyclic aromatic hydrocarbons (PAHs) between two successive

Rufeng LI,Chenghong FENG,Dongxin WANG,Baohua LI,Zhenyao SHEN

《环境科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 381-389 doi: 10.1007/s11783-015-0817-7

摘要: Successive sediment suspensions often happen in estuary, yet little research has probed into the difference in the release behaviors of organic compounds among different suspensions. This study took polycyclic aromatic hydrocarbons (PAHs) as typical organic contaminants and investigated the release behaviors between two successive suspensions with a particle entrainment simulator (PES). Results showed that successive sediment suspensions lowered the concentration of dissolved PAHs in the overlying water via facilitating the re-adsorption of dissolved PAHs onto the suspended particles. Fast-release and slow-release periods of PAHs were successively observed in the both suspensions. The concentration changes of dissolved PAHs in the second suspension were generally similar with but hysteretic to those in the first suspension. More vigorous desorption and re-absorption of PAHs were induced in the second suspension. Successive sediment suspensions obviously decreased the concentrations of mineral composition and organic matters in the overlying water, which significantly affects multiphase distribution of PAHs.

关键词: sediment suspension     PAHs     multiphase distribution     distribution coefficients    

Solar fuel from photo-thermal catalytic reactions with spectrum-selectivity: a review

Sanli TANG, Jie SUN, Hui HONG, Qibin LIU

《能源前沿(英文)》 2017年 第11卷 第4期   页码 437-451 doi: 10.1007/s11708-017-0509-z

摘要: Solar fuel is one of the ideal energy sources in the future. The synergy of photo and thermal effects leads to a new approach to higher solar fuel production under relatively mild conditions. This paper reviews different approaches for solar fuel production from spectrum-selective photo-thermal synergetic catalysis. The review begins with the meaning of synergetic effects, and the mechanisms of spectrum-selectivity and photo-thermal catalysis. Then, from a technical perspective, a number of experimental or theoretical works are sorted by the chemical reactions and the sacrificial reagents applied. In addition, these works are summarized and tabulated based on the operating conditions, spectrum-selectivity, materials, and productivity. A discussion is finally presented concerning future development of photo-thermal catalytic reactions with spectrum-selectivity.

关键词: photo-thermal catalysis     spectrum-selectivity     solar fuel     full-spectrum    

标题 作者 时间 类型 操作

Multiphase surfactant-assisted reaction-separation system in a microchannel reactor

Salah ALJBOUR, Tomohiko TAGAWA, Mohammad MATOUQ, Hiroshi YAMADA

期刊论文

Sustainable functionalization and modification of materials via multicomponent reactions in water

期刊论文

Extended two-fluid model applied to analysis of bubbly flow in multiphase rotodynamic pump impeller

Zhiyi YU, Guoyu WANG, Shuliang CAO

期刊论文

Application of different CFD multiphase models to investigate effects of baffles and nanoparticles on

Ali SHAHMOHAMMADI,Arezou JAFARI

期刊论文

Simulating multiphase flow in a two-stage pusher centrifuge using computational fluid dynamics

Chong PANG, Wei TAN, Endian SHA, Yuanqing TAO, Liyan LIU

期刊论文

Latest progress in numerical simulations on multiphase flow and thermodynamics in production of natural

Lin ZUO, Lixia SUN, Changfu YOU

期刊论文

Erosion-corrosion failure of REAC pipes under multiphase flow

Ping TANG, Jian YANG, Jinyang ZHENG, Shizheng HE, Jianjun YE, Guofu OU, Ieong WONG, Yanbao MA,

期刊论文

Redox reactions of iron and manganese oxides in complex systems

Jianzhi Huang, Huichun Zhang

期刊论文

Kinetic Monte Carlo simulations of plasma-surface reactions on heterogeneous surfaces

Daniil Marinov

期刊论文

Numerical simulation and experimental verification of chemical reactions for SCR DeNO

Qiang ZHANG, Yonglin FAN, Wenyan LI

期刊论文

Chemical reactions of oily sludge catalyzed by iron oxide under supercritical water gasification condition

期刊论文

Experimental investigation of multiphase flow behavior in drilling annuli using high speed visualization

Alap Ali ZAHID, Syed Raza ur REHMAN, Anwarul HASAN, S. RUSHD, Mohammad Azizur RAHMAN

期刊论文

Research progress on hydrate plugging in multiphase mixed rich-liquid transportation pipelines

Shuyu SONG, Zhiming LIU, Li ZHOU, Liyan SHANG, Yaxin WANG

期刊论文

Multiphase redistribution differences of polycyclic aromatic hydrocarbons (PAHs) between two successive

Rufeng LI,Chenghong FENG,Dongxin WANG,Baohua LI,Zhenyao SHEN

期刊论文

Solar fuel from photo-thermal catalytic reactions with spectrum-selectivity: a review

Sanli TANG, Jie SUN, Hui HONG, Qibin LIU

期刊论文