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ZnZr/HZSM-5 as efficient catalysts for alkylation of benzene with carbon dioxide

《化学科学与工程前沿(英文)》 2023年 第17卷 第4期   页码 404-414 doi: 10.1007/s11705-022-2215-6

摘要: Alkylation of benzene with carbon dioxide and hydrogen to produce toluene and xylene could increase the added-value of surplus benzene as well as relieve environmental problems like green-house effect. In this work, the alkylation benzene with carbon dioxide and hydrogen reaction was proceeded by using the mixture of zinc-zirconium oxide and HZSM-5 as bifunctional catalyst. The equivalent of Zn/Zr = 1 displays the best catalytic performance at 425 °C and 3.0 MPa, and benzene conversion reaches 42.9% with a selectivity of 90% towards toluene and xylene. Moreover, the carbon dioxide conversion achieves 23.3% and the carbon monoxide selectivity is lower than 35%, indicating that more than 50% carbon dioxide has been effectively incorporated into the target product, which is the best result as far as we know. Combined with characterizations, it indicated that the Zn and Zr formed a solid solution under specific conditions (Zn/Zr = 1). The as-formed solid solution not only possesses a high surface area but also provides a large amount of oxygen vacancies. Additionally, the bifunctional catalyst has excellent stabilities that could keep operating without deactivation for at least 80 h. This work provides promising industrial applications for the upgrading of aromatics.

关键词: carbon dioxide     alkylation of benzene     solid solution catalyst     bifunctional catalyst    

Investigation of phosphate adsorption from an aqueous solution using spent fluid catalytic cracking catalyst

Zhen Li, Zhaofu Qiu, Ji Yang, Benteng Ma, Shuguang Lu, Chuanhui Qin

《环境科学与工程前沿(英文)》 2018年 第12卷 第6期 doi: 10.1007/s11783-018-1082-3

摘要:

Spent FCC catalyst with lanthanum is proposed as a novel P-removal adsorbent.

The spent FCC catalyst exhibits 99% adsorption efficiency for low P-concentration wastewater (C0 <5.0 mg/L).

High affinity, endothermic reaction and fast sorption kinetics are achieved.

The phosphate is adsorbed in the form of LaPO4 and KH2PO4.

关键词: Spent FCC catalyst     Phosphate removal     Adsorption     Lanthanum    

Review of SO42-/MxOy solid superacid catalysts

Yanni WU, Shijun LIAO

《化学科学与工程前沿(英文)》 2009年 第3卷 第3期   页码 330-343 doi: 10.1007/s11705-009-0208-3

摘要: Some metal oxides modified with sulfate ions form highly acidic or superacidic catalysts. solid superacid catalysts, play a vital role in more and more fields such as organic synthesis, fine chemicals, pharmaceuticals, and means for strengthening environmental safeguards. This review highlights the recent development of solid superacid catalysts based on , including synthesis method, characterization of acid sites and acid strength, and applications.

关键词: solid superacid catalyst     synthesis method     characterization     applications    

Yue’s solution of classical elasticity in

Zhong-qi Quentin YUE

《结构与土木工程前沿(英文)》 2015年 第9卷 第3期   页码 215-249 doi: 10.1007/s11709-015-0298-6

摘要: This paper presents the exact and complete fundamental singular solutions for the boundary value problem of a -layered elastic solid of either transverse isotropy or isotropy subject to body force vector at the interior of the solid. The layer number is an arbitrary nonnegative integer. The mathematical theory of linear elasticity is one of the most classical field theories in mechanics and physics. It was developed and established by many well-known scientists and mathematicians over 200 years from 1638 to 1838. For more than 150 years from 1838 to present, one of the remaining key tasks in classical elasticity has been the mathematical derivation and formulation of exact solutions for various boundary value problems of interesting in science and engineering. However, exact solutions and/or fundamental singular solutions in closed form are still very limited in literature. The boundary-value problems of classical elasticity in -layered and graded solids are also one of the classical problems challenging many researchers. Since 1984, the author has analytically and rigorously examined the solutions of such classical problems using the classical mathematical tools such as Fourier integral transforms. In particular, he has derived the exact and complete fundamental singular solutions for elasticity of either isotropic or transversely isotropic layered solids subject to concentrated loadings. The solutions in -layered or graded solids can be calculated with any controlled accuracy in association with classical numerical integration techniques. Findings of this solution formulation are further used in the companion paper for mathematical verification of the solutions and further applications for exact and complete solutions of other problems in elasticity, elastodynamics, poroelasticty and thermoelasticity. The mathematical formulations and solutions have been named by other researchers as Yue’s approach, Yue’s treatment, Yue’s method and Yue’s solution.

关键词: elasticity     solution     layered solid     graded material    

Preparation of ceria-zirconia solid solution with enhanced oxygen storage capacity and redox performance

Lijing MENG, Licheng LIU, Xuehong ZI, Hongxing DAI, Hong HE, Zhen ZHAO, Xinping WANG,

《环境科学与工程前沿(英文)》 2010年 第4卷 第2期   页码 164-171 doi: 10.1007/s11783-010-0019-2

摘要: A new method called ultrasonic-assisted membrane reaction (UAMR) was reported for the fabrication of ceria-zirconia solid solution. A series of ceria-zirconia solid solutions with different Ce/Zr molar ratios were prepared by the UAMR method and characterized by X-ray diffraction (XRD), N adsorption, hydrogen temperature-programmed reduction (H-TPR), scanning electron microscope (SEM), and transmission electron microscopy (TEM) techniques. The UAMR method proved to be superior, especially when the Ce/Zr molar ratio was lower than 1, in fabricating ceria-zirconia solid solutions with large BET surface area, high oxygen storage capacity (OSC), and low reduction temperature.

关键词: membrane reaction     ceria-zirconia     Ce/Zr molar ratio     solid solution     hydrogen temperature-programmed reduction (H2-TPR)    

Sulfonic acid-functionalized mesoporous silica catalyst with different morphology for biodiesel production

《化学科学与工程前沿(英文)》 2022年 第16卷 第8期   页码 1198-1210 doi: 10.1007/s11705-021-2133-z

摘要: Sulfonic acid functionalized mesoporous silica based solid acid catalysts with different morphology were designed and fabricated. The synthesized materials were characterized by various physicochemical and spectroscopic techniques like scanning electron microscope-energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller surface area, thermogravimetric analysis and n-butylamine acidity. The shape of catalysts particles plays an important role in its activity. The sulfonic acid functionalized mesoporous silica catalysts of spherical shape and the cube shape were assessed for catalytic activity in biodiesel production. The catalytic biodiesel production reaction over the catalysts were studied by esterification of free fatty acid, oleic acid with methanol. The effect of various reaction parameters such as catalyst concentration, acid/alcohol molar ratio, catalyst amount, reaction temperature and reaction time on catalytic activity were investigated to optimize the conditions for maximum conversion. It was sulfonated cubic shape mesoporous silica which exhibited better activity as compared to the spherical shape silica catalysts. Additionally, the catalyst was regenerated and reused up to three cycles without any significant loss in activity. The present catalysts exhibit superior performance in biodiesel production and it can be used for the several biodiesel feedstock’s that are rich in free fatty acids.

关键词: solid acid catalyst     mesoporous silica     sulfonic acid     biodiesel     esterification     oleic acid    

Development of solid base catalyst X/Y/MgO/-AlO for optimization of preparation of biodiesel from L.seed

WANG Rui, YANG Song, YIN Shitao, SONG Baoan, BHADURY Pinaki S., XUE Wei, TAO Shuwei, JIA Zhaohui, LIU Da, GAO Liang

《化学科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 468-472 doi: 10.1007/s11705-008-0074-4

摘要: The preparation and regeneration conditions of the identified catalyst X/Y/MgO/-AlO with high catalytic activity were studied and optimized. The biodiesel was prepared by transesterification of seed oil produced in Guizhou with methanol at its reflux temoerature in the presence of X/Y/MgO/-AlO The pilot plant tests were carried out in a 100 L reaction vessel. Both average yield and fatty acid methyl esters (FAME) content reached more than 96.50% under the optimum reaction conditions of the pilot plant tests designed with an oil/methanol molar ratio of 1 : 10, catalyst concentration of 1.00%, and reaction time of 3 h at reflux temperature. In addition, analysis shows that the quality of biodiesel meets the standard EN 14214.

关键词: temperature     presence     addition     catalytic activity     catalyst X/Y/MgO/-AlO    

Precise regulation of acid pretreatment for red mud SCR catalyst: Targeting on optimizing the acidity

《环境科学与工程前沿(英文)》 2022年 第16卷 第7期 doi: 10.1007/s11783-021-1447-x

摘要:

• The optimum SCR activity was realized by tuning the acid pretreatment.

关键词: Air pollution control     Nitrogen oxides     Selective catalytic reduction     Red mud     Solid waste utilization    

Methane partial oxidation over NiO-MgO/Ce

Piyawat PUE-ON, Vissanu MEEYOO, Thirasak RIRKSOMBOOON

《化学科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 289-296 doi: 10.1007/s11705-013-1345-2

摘要: Methane partial oxidation (MPO) is considered as an alternative method to produce hydrogen because it is an exothermic reaction to afford a suitable H /CO ratio of 2. However, carbon deposition on a catalyst is observed as a major cause of catalyst deactivation in MPO. In order to find suitable catalysts that prevent the carbon deposition, NiO-MgO/Ce Zr O (CZO) supported catalysts were prepared via the co-impregnation (C) and sequential incipient wetness impregnation (S) methods. The amount of Ni loading was fixed at 15 wt-% whereas the amount of MgO loading was varied from 5 to 15 wt-%. The results revealed that the addition of MgO shifted the light-off temperatures to higher temperatures. This is because the Ni surface was partially covered with MgO, and the strong interaction between NiO and NiMgO over CZO support led to the difficulty in reducing NiO to active Ni and thus less catalytic activity. However, among the catalysts tested, the 15Ni5Mg/CZO (S) catalyst exhibited the best catalytic stability for MPO after 18 h on stream at 750°C. Moreover, this catalyst had a better resistance to carbon deposition due to its high metallic Ni dispersion at high temperature.

关键词: methane partial oxidation     NiO     ceria-zirconia     MgO     mixed oxide solid solution    

A review of optimization modeling and solution methods in renewable energy systems

《工程管理前沿(英文)》   页码 640-671 doi: 10.1007/s42524-023-0271-3

摘要: The advancement of renewable energy (RE) represents a pivotal strategy in mitigating climate change and advancing energy transition efforts. A current of research pertains to strategies for fostering RE growth. Among the frequently proposed approaches, employing optimization models to facilitate decision-making stands out prominently. Drawing from an extensive dataset comprising 32806 literature entries encompassing the optimization of renewable energy systems (RES) from 1990 to 2023 within the Web of Science database, this study reviews the decision-making optimization problems, models, and solution methods thereof throughout the renewable energy development and utilization chain (REDUC) process. This review also endeavors to structure and assess the contextual landscape of RES optimization modeling research. As evidenced by the literature review, optimization modeling effectively resolves decision-making predicaments spanning RE investment, construction, operation and maintenance, and scheduling. Predominantly, a hybrid model that combines prediction, optimization, simulation, and assessment methodologies emerges as the favored approach for optimizing RES-related decisions. The primary framework prevalent in extant research solutions entails the dissection and linearization of established models, in combination with hybrid analytical strategies and artificial intelligence algorithms. Noteworthy advancements within modeling encompass domains such as uncertainty, multienergy carrier considerations, and the refinement of spatiotemporal resolution. In the realm of algorithmic solutions for RES optimization models, a pronounced focus is anticipated on the convergence of analytical techniques with artificial intelligence-driven optimization. Furthermore, this study serves to facilitate a comprehensive understanding of research trajectories and existing gaps, expediting the identification of pertinent optimization models conducive to enhancing the efficiency of REDUC development endeavors.

关键词: renewable energy system     bibliometrics     mathematical programming     optimization models     solution methods    

Formic acid dehydrogenation reaction on high-performance PdAu alloy nanoparticles prepared by the eco-friendly slow synthesis methodology

《能源前沿(英文)》   页码 751-762 doi: 10.1007/s11708-023-0895-3

摘要: Dehydrogenation of formic acid (FA) is considered to be an effective solution for efficient storage and transport of hydrogen. For decades, highly effective catalysts for this purpose have been widely investigated, but numerous challenges remain. Herein, the PdxAu1−x (x = 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1) alloys over the whole composition range were successfully prepared and used to catalyze FA hydrogen production efficiently near room temperature. Small PdAu nanoparticles (5–10 nm) were well-dispersed and supported on the activated carbon to form PdAu solid solution alloys via the eco-friendly slow synthesis methodology. The physicochemical properties of the PdAu alloys were comprehensively studied by utilizing various measurement methods, such as X-ray diffraction (XRD), N2 adsorption–desorption, high angle annular dark field-scanning transmission electron microscope (HAADF-STEM), X-ray photoelectrons spectroscopy (XPS). Notably, owing to the strong metal-support interaction (SMSI) and electron transfer between active metal Au and Pd, the Pd0.5Au0.5 obtained exhibits a turnover frequency (TOF) value of up to 1648 h−1 (313 K, nPd+Au/nFA = 0.01, nHCOOH/nHCOONa = 1:3) with a high activity, selectivity, and reusability in the FA dehydrogenation.

关键词: FA dehydrogenation     face-centred cubic structures     PdAu solid solution alloy nanoparticles     slow synthesis methodology     SMSI effect    

The smoothed finite element method (S-FEM): A framework for the design of numerical models for desired solutions

Gui-Rong Liu

《结构与土木工程前沿(英文)》 2019年 第13卷 第2期   页码 456-477 doi: 10.1007/s11709-019-0519-5

摘要:

The smoothed finite element method (S-FEM) was originated by G R Liu by combining some meshfree techniques with the well-established standard finite element method (FEM). It has a family of models carefully designed with innovative types of smoothing domains. These models are found having a number of important and theoretically profound properties. This article first provides a concise and easy-to-follow presentation of key formulations used in the S-FEM. A number of important properties and unique features of S-FEM models are discussed in detail, including 1) theoretically proven softening effects; 2) upper-bound solutions; 3) accurate solutions and higher convergence rates; 4) insensitivity to mesh distortion; 5) Jacobian-free; 6) volumetric-locking-free; and most importantly 7) working well with triangular and tetrahedral meshes that can be automatically generated. The S-FEM is thus ideal for automation in computations and adaptive analyses, and hence has profound impact on AI-assisted modeling and simulation. Most importantly, one can now purposely design an S-FEM model to obtain solutions with special properties as wish, meaning that S-FEM offers a framework for design numerical models with desired properties. This novel concept of numerical model on-demand may drastically change the landscape of modeling and simulation. Future directions of research are also provided.

关键词: computational method     finite element method     smoothed finite element method     strain smoothing technique     smoothing domain     weakened weak form     solid mechanics     softening effect     upper bound solution    

Modeling nanostructured catalyst layer in PEMFC and catalyst utilization

Jiejing ZHANG, Pengzhen CAO, Li XU, Yuxin WANG

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 297-302 doi: 10.1007/s11705-011-1201-1

摘要: A lattice model of the nanoscaled catalyst layer structure in proton exchange membrane fuel cells (PEMFC) was established by Monte Carlo method. The model takes into account all the four components in a typical PEMFC catalyst layer: platinum (Pt), carbon, ionomer and pore. The elemental voxels in the lattice were set fine enough so that each average sized Pt particulate in Pt/C catalyst can be represented. Catalyst utilization in the modeled catalyst layer was calculated by counting up the number of facets of Pt voxels where “three phase contact” are met. The effects of some factors, including porosity, ionomer content, Pt/C particle size and Pt weight percentage in the Pt/C catalyst, on catalyst utilization were investigated and discussed.

关键词: catalyst layer     PEM fuel cell     lattice model     Monte Carlo method     catalyst utilization    

Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

《机械工程前沿(英文)》 2008年 第3卷 第1期   页码 28-36 doi: 10.1007/s11465-008-0007-4

摘要: This research focuses on the characteristics of how a ball-screw changes its temperature corresponding to the periodic change of the end-most heat source. Based on the theory of heat transfer, this paper supplies a numerical solution to the non-homogeneous equation of heat transfer through the group explicit (GE) finite difference approach. The temperature distribution for the ball-screw at different times and directions is shown. By simulating and modeling the temperature field and thermal deformation of the ball-screw under periodically varying heat sources, this paper describes the thermal dynamic characteristics of the ball-screw under such conditions. By testing the thermal dynamic characteristics of the ball-screw, the numerical solution is validated.

关键词: numerical solution     temperature corresponding     temperature distribution     end-most     ball-screw    

Analytical dynamic solution of a flexible cable-suspended manipulator

Mahdi BAMDAD

《机械工程前沿(英文)》 2013年 第8卷 第4期   页码 350-359 doi: 10.1007/s11465-013-0271-9

摘要:

Cable-suspended manipulators are used in large scale applications with, heavy in weight and long in span cables. It seems impractical to maintain cable assumptions of smaller robots for large scale manipulators. The interactions among the cables, platforms and actuators can fully evaluate the coupled dynamic analysis. The structural flexibility of the cables becomes more pronounced in large manipulators. In this paper, an analytic solution is provided to solve cable vibration. Also, a closed form solution can be adopted to improve the dynamic response to flexibility. The output is provided by the optimal torque generation subject to the actuator limitations in a mechatronic sense. Finally, the performance of the proposed algorithm is examined through simulations.

关键词: parallel robot     flexible cable     suspended robot     dynamic    

标题 作者 时间 类型 操作

ZnZr/HZSM-5 as efficient catalysts for alkylation of benzene with carbon dioxide

期刊论文

Investigation of phosphate adsorption from an aqueous solution using spent fluid catalytic cracking catalyst

Zhen Li, Zhaofu Qiu, Ji Yang, Benteng Ma, Shuguang Lu, Chuanhui Qin

期刊论文

Review of SO42-/MxOy solid superacid catalysts

Yanni WU, Shijun LIAO

期刊论文

Yue’s solution of classical elasticity in

Zhong-qi Quentin YUE

期刊论文

Preparation of ceria-zirconia solid solution with enhanced oxygen storage capacity and redox performance

Lijing MENG, Licheng LIU, Xuehong ZI, Hongxing DAI, Hong HE, Zhen ZHAO, Xinping WANG,

期刊论文

Sulfonic acid-functionalized mesoporous silica catalyst with different morphology for biodiesel production

期刊论文

Development of solid base catalyst X/Y/MgO/-AlO for optimization of preparation of biodiesel from L.seed

WANG Rui, YANG Song, YIN Shitao, SONG Baoan, BHADURY Pinaki S., XUE Wei, TAO Shuwei, JIA Zhaohui, LIU Da, GAO Liang

期刊论文

Precise regulation of acid pretreatment for red mud SCR catalyst: Targeting on optimizing the acidity

期刊论文

Methane partial oxidation over NiO-MgO/Ce

Piyawat PUE-ON, Vissanu MEEYOO, Thirasak RIRKSOMBOOON

期刊论文

A review of optimization modeling and solution methods in renewable energy systems

期刊论文

Formic acid dehydrogenation reaction on high-performance PdAu alloy nanoparticles prepared by the eco-friendly slow synthesis methodology

期刊论文

The smoothed finite element method (S-FEM): A framework for the design of numerical models for desired solutions

Gui-Rong Liu

期刊论文

Modeling nanostructured catalyst layer in PEMFC and catalyst utilization

Jiejing ZHANG, Pengzhen CAO, Li XU, Yuxin WANG

期刊论文

Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

期刊论文

Analytical dynamic solution of a flexible cable-suspended manipulator

Mahdi BAMDAD

期刊论文