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Numerical investigation of complex chemistry performing in Ptcatalyzed oxidative dehydrogenation of ethane fixed-bed reactors

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Chinese Journal of Chemical Engineering 2020年第3期28卷 793-807页

作者： Zhongfeng Geng Hao Deng Yonghui Li minhua zhang Key Laboratory for Green Chemical Technology of Ministry of Education.R&D Center for Petrochemical Technology Tianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072China

Ethylene is one of the most important basic chemicals in the modern chemical *** or catalytic cracking of hydrocarbons is the main industrial technologies nowadays,which suffer from equilibriumlimitation and rapid coke *** oxidative dehydrogenation of ethane(ODHE)is considered to be a promising alternative process since it overcomes equilibrium-limitations,avoids catalyst deactivation by coke formation,and decreases the number of side *** this study,particle-resolved 2 D CFD simulations of fixed-beds filled with eggshell catalysts coupled with micro-kinetics of Pt-catalyzed ODHE were performed to understand the effect of operation conditions and catalyst properties on ethylene *** catalyst bed was created by discrete element method(DEM)and the central longitudinal section of the reactor tube was defined as the 2 D simulation *** of the homogeneous and catalytic heterogeneous chemical reactions were described by detailed micro-kinetics within the particle-resolved CFD *** first,the established model of monolith reactors was verified by comparing the simulated results with experimental results reported in ***,the effects of operation conditions and catalyst concentration on the ethylene selectivity in randomly packed beds were *** specific variation of certain operation conditions including inlet flow rate,inlet temperature,pressure,inlet C2 H6/O2 ratio and N2 dilution ratio can effectively increase ethylene *** the reduction of ratio of catalytic active area to geometric area Fcat/georepresenting catalyst properties from 140 to 30 increases the selectivity from 42.2%to 59.3%.This research can provide reference for the industrialization of ODHE process in the future.

关键词： Ethane Ethylene Oxidative dehydrogenation Selectivity CFD Fixed-bed

Metal-organic framework loaded manganese oxides as efficient catalysts for low-temperature selective catalytic reduction of NO with NH3

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Frontiers of Chemical Science and Engineering 2017年第4期11卷 594-602页

作者： zhang, minhua Huang, Baojuan Jiang, Haoxi Chen, Yifei Tianjin Univ Key Lab Green Chem Technol Minist Educ R&D Ctr Petrochem Technol Tianjin 300072 Peoples R China Collaborat Innovat Ctr Chem Sci & Engn Tianjin 300072 Peoples R China

A mild in-situ deposition method was used to fabricate Mn-based catalysts on a UiO-66 carder for the selective catalytic reduction of NO by NH3 （NH3-SCR）. The catalyst with 8.5 wt-% MnOx loading had the highest catalytic activity for NH3-SCR with a wide temperature window （100-290 C） for 90% NO conversion. Char- acterization of the prepared MnOx/UiO-66 catalysts showed that the catalysts had the crystal structure and porosity of the UiO-66 carrier and that the manganese particles were well-distributed on the surface of the catalyst. X-ray photoelectron spectroscopy analysis showed that there are strong interactions between the MnOx and the Zr oxide secondary building units of the UiO-66 which has a positive effect on the catalytic activity. The 8.5 wt-% MnOx catalyst maintained excellent activity during a 24-h stability test and exhibited good resistance to SO2 poisoning.

关键词： metal-organic framework selective catalyticreduction manganese oxides deNOx SO2 resistance

Research progress in the SO2 resistance of the catalysts for selective catalytic reduction of NOx

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Chinese Journal of Chemical Engineering 2017年第12期25卷 1695-1705页

作者： minhua zhang Baojuan Huang Haoxi Jiang Yifei Chen Key Laboratory for Green Chemical Technology of Ministry of Education R&D Center for Petrochemical Technology Tianjin University Tianjin 300072 China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China

The selective catalytic reduction （SCR） of NOx with NH3 has been proven to be an efficient technology for NOx conversion to N2. However, the catalysts used for SCR usually suffer from the problem of sulfur poisoning which seriously limits their practical application. This review summarized sulfur poisoning mechanisms of various SCR deNG catalysts and strategies to reduce deactivation caused by SO2 such as doping metals, controlling the structures and morphologies of the catalysts, and selecting appropriate supports. The methods and procedures of catalysts preparation and the reaction conditions also have effect on SO2-resistance of the catalysts. Several novel catalyst systems that exhibited good SO2 resistance are also introduced. This paper could provide guidance for the development of highly efficient sulfur-tolerant deNOx catalysts.

关键词： Words Selective catalytic reduction (SCR)SO2 resistance catalyst NOx

Mechanistic understanding of Cu-based bimetallic catalysts

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Frontiers of Chemical Science and Engineering 2020年第5期14卷 689-748页

作者： You Han Yulian Wang Tengzhou Ma Wei Li Jinli zhang minhua zhang School of Chemical Enginering and Technology Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Membrane Science and Desalination Technology Tianjin UniversityTianjin 300072China School of Chemistry and Chemical Engineering Shihezi UniversityShihezi 832003China Key Laboratory for Green Chemical Technology of Ministry of Education Research and Development Center for Petrochemical TechnologyTianjin UniversityTianjin 300072China

Copper has received extensive attention in the field of catalysis due to its rich natural reserves,low cost,and superior catalytic ***,we reviewed two modification mechanisms of co-catalyst on the coordination environment change of Cu-based catalysts:(1)change the electronic orbitals and geometric structure of Cu without any catalytic functions;(2)act as an additional active site with a certain catalytic function,as well as their catalytic mechanism in major reactions,including the hydrogenation to alcohols,dehydrogenation of alcohols,water gas shift reaction,reduction of nitrogenous compounds,electrocatalysis and *** influencing mechanisms of different types of auxiliary metals on the structure-activity relationship of Cu-based catalysts in these reactions were especially summarized and *** mechanistic understanding can provide significant guidance for the design and controllable synthesis of novel Cu-based catalysts used in many industrial reactions.

关键词： copper bimetallic catalyst coordination modification mechanism catalytic application

Optimization of a synthetic medium for ethanol production by xylose-fermenting Zymomonas mobilis using response surface methodology

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Chinese Science Bulletin 2012年第28期57卷 3782-3789页

作者： DONG HuiNa ZHAO XueMing MA YuanYuan zhang minhua Tianjin University R&D Center for Petrochemical Technology Tianjin UniversityTianjin 300072China Department of Biochemical Engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China State Key Laboratory of Engines Tianjin UniversityTianjin 300072China Key Laboratory of Systems Bioengineering Ministry of EducationTianjin UniversityTianjin 300072China Edinburgh-Tianjin Joint Research Centre for Systems Biology and Synthetic Biology Tianjin UniversityTianjin 300072China

A synthetic medium for ethanol production by recombinant xylose-fermenting Zymomonas mobilis was optimized using Plackett-Burman(PB) design and response surface methodology(RSM).The effects of 19 medium components were investigated by PB *** of these components were determined to have significant effects on ethanol *** statistical model was constructed via central composite design(CCD) using five selected variables,including xylose,trisodium citrate,choline chloride,pyridoxine,and *** validity of the developed model was *** ethanol concentration in the optimized medium was 6.7% higher than in the RM *** optimized medium was then simplified to give the final synthetic medium(S2),in which the ethanol concentration was 20.7% higher than in the RM *** and trisodium citrate were the key medium components influencing ethanol production,while calcium pantothenate was the only growth factor required by recombinant *** production and growth response were directly proportional to the logarithm of the concentration of trisodium citrate in the range of 0.1-1.6 g/L.

关键词：合成培养基乙醇生产优化重组发酵单胞菌木糖发酵响应曲面法中心复合设计柠檬酸三钠

Dissipative Particle Dynamics Simulations of the Self-assembly Mechanisms of Fluorinated Ordered Mesoporous Carbon in the Aqueous Phase

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Transactions of Tianjin University 2019年第5期25卷 559-566页

作者： Na Sun minhua zhang Xiuqin Dong Lingtao Wang R&D Center of Petrochemical Technology Tianjin UniversityTianjin 300072China Key Laboratory for Green Chemical Technology of Ministry of Education Tianjin UniversityTianjin 300072China

To clarify the preparation mechanisms of uorinated ordered mesoporous carbon materials (FOMCs), the dissipative par- ticle dynamics method was used to simulate the self-assembly process of the amphiphilic triblock poly(ethylene oxide)- poly(propylene oxide)-poly(ethylene oxide) copolymer Pluronic F127 in the aqueous system. The self-assembly mechanisms in aqueous phase and the formation mechanisms of micropores and mesopores were investigated. It was found that the mesoporous structure of the FOMCs was formed by the hydrophobic segments of F127, while the pore wall was formed by both the hydrophilic segments and the carbon precursor in the system. The microporous structure on the pore wall was con- structed by the carbon source in the hydrophilic segments’ spaces after the template was removed. Our ndings could provide understanding and knowledge for the synthesis of mesoporous carbon by the self-assembly method on the mesoscopic scale.

关键词： Mesoporous carbon Dissipative particle dynamics Self-assembly Mesopore Micropore

Mechanisms of Transforming CH_x to CO on Ni(111) Surface by Density Functional Theory

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Transactions of Tianjin University 2019年第4期25卷 330-339页

作者： Yingzhe Yu Hao Lei Lingguang Wang minhua zhang Key Laboratory for Green Chemical Technology of Ministry of Education R&D Center for Petrochemical TechnologyTianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072China

To elucidate feasible routes of producing CO from CH 3 and unravel the eff ect of adsorbed O on CH x transformation, the reactivity of CH x ( x = 1-3) with and without the assistance of adsorbed atomic O on Ni(111) was explored using density functional theory calculations. The adsorption energies of CH x ( x = 0-3) were found to be signifi cantly reduced on an O-preadsorbed Ni(111) surface compared to a pure surface. Furthermore, O-assisted one-step dehydrogenation of CH x ( x = 1-3) features energy barriers and thus is diffi cult to proceed. In terms of energy, the direct dissociation of CH 3 is favorable, except for the last CH dehydrogenation, which is energy intensive. Interestingly, in O-assisted two-step CH transformation to CO via CHO intermediate, the barrier is dramatically lowered. The successive dehydrogenations of CH x O ( x = 1-3) were also found to be a route for CO formation. Finally, two possible pathways from CH 3 to CO are proposed:(a) CH 3 → CH 2 → CH → CHO → CO;(b) CH 3 → CH 3 O → CH 2 O → CHO → CO.

关键词： Density functional theory CH x transformation CO Ni(111)

CFD Simulation of the Two-Phase Flow in a Novel Cooking Tank for Ethanol Production

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Transactions of Tianjin University 2018年第3期24卷 212-223页

作者： Cheng Liu Yang Lu Yan Zhou Xuanwen Zhu minhua zhang Zhongfeng Geng Key Laboratory for Green Chemical Technology of Ministry of Education Tianjin University R&D Center for Petrochemical TechnologyTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072China

As a key piece of equipment in bioethanol production, cooking tank is usually used to ensure the uniformity of liquefaction. In this paper, we propose a novel type of cooking tank to ensure a type of starch slurry flow known as a quasi-plug flow in a large-scale process. In the analyses of flow field, we used computational fl uid dynamics(CFD). To simulate the liquid–solid two-phase flow, we chose a Euler–Euler model based on particle dynamics. We investigated the eff ects of several key structural parameters on the flow field. The results show that for a tank with 12,800 mm in height and 1000 mm in diameter, the optimized inlet tube angle and inlet tube diameter range from 0° to 45° and 0.125 to 0.15 D(diameter of cooking tank), respectively. We determined the optimum cone mouth diameter at the exit and its distance to the bottom to range from 0.18 to 0.30 D and 0.045 to 0.070 D, respectively. The analysis results suggest that the tank performs well when its aspect ratio ranges from 9.62 to 12.8. Our findings provide a theoretical basis for designing and optimizing the cooking tank.

关键词： Cooking tank Computational fluid dynamics Euler-Euler model Particle dynamics Structural optimization

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滚珠丝杠副传动效率的模型建立及试验研究

仪器仪表学报 2023年第2期44卷 175-183页

作者：张敏华祖莉徐子杰南京理工大学机械工程学院南京210094 数控机床功能部件共性技术工业和信息化部重点实验室张家港215600

传动效率是衡量滚珠丝杠副的传动性能的重要指标,目前传动效率的研究对接触面的摩擦润滑情况缺少深入分析,试验研究较少且多是针对某型号样件。为了得到更符合实际情况的传动效率模型并对传动效率影响因素进行分析,基于载荷分布理论,分... 详细信息

传动效率是衡量滚珠丝杠副的传动性能的重要指标,目前传动效率的研究对接触面的摩擦润滑情况缺少深入分析,试验研究较少且多是针对某型号样件。为了得到更符合实际情况的传动效率模型并对传动效率影响因素进行分析,基于载荷分布理论,分析考虑工艺误差的滚珠丝杠副承载运动情况,再结合弹流润滑理论得到滚珠丝杠副在不同工况下的摩擦系数变化规律,从而得到新的传动效率模型,再对传动效率影响因素进行计算和分析,最终设计试验验证传动效率模型并分析不同轴向负载、转速、预紧力、润滑粘度对传动效率的影响。试验结果表明新模型的计算值与试验值的相对误差最大为6.42%,验证了新模型的有效性与合理性。

关键词：滚珠丝杠副工艺误差弹流润滑传动效率模型影响因素试验研究