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Probing deactivation by coking in catalyst pellets for dry reforming of methane using a pore network model

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Chinese Journal of Chemical Engineering 2023年第3期55卷 293-303页

作者： Yu Wang Qunfeng Zhang Xinlei Liu Junqi Weng Guanghua Ye Xinggui Zhou State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

Dry reforming of methane(DRM) is an attractive technology for utilizing the greenhouse gases(CO_(2) and CH_(4)) to produce syngas. However, the catalyst pellets for DRM are heavily plagued by deactivation by coking, which prevents this technology from commercialization. In this work, a pore network model is developed to probe the catalyst deactivation by coking in a Ni/Al_(2)O_(3) catalyst pellet for DRM. The reaction conditions can significantly change the coking rate and then affect the catalyst deactivation. The catalyst lifetime is higher under lower temperature, pressure, and CH_(4)/CO_(2) molar ratio, but the maximum coke content in a catalyst pellet is independent of these reaction conditions. The catalyst pellet with larger pore diameter, narrower pore size distribution and higher pore connectivity is more robust against catalyst deactivation by coking, as the pores in this pellet are more difficult to be plugged or inaccessible.The maximum coke content is also higher for narrower pore size distribution and higher pore connectivity, as the number of inaccessible pores is lower. Besides, the catalyst pellet radius only slightly affects the coke content, although the diffusion limitation increases with the pellet radius. These results should serve to guide the rational design of robust DRM catalyst pellets against deactivation by coking.

关键词： Deactivation by coking Dry reforming of methane Pore network model Diffusion limitation Catalyst pellet

Understanding the effects of electrode meso-macropore structure and solvent polarity on electric double layer capacitors based on a continuum model

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Chinese Journal of Chemical Engineering 2022年第10期50卷 423-434页

作者： Haotian Lu Jinghong zhou Yueqiang Cao Tongxin Shang Guanghua Ye Quan-Hong Yang Xinggui Zhou State-Key Laboratory of Chemical Engineering East China University of Science of TechnologyShanghai 200237China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou 350207China Nanoyang Group State Key Laboratory of Chemical EngineeringSchool of Chemical Engineering and TechnologyTianjin UniversityTianjin 300350China

The structures of electrode meso-macropore and the solvent polarity are the crucial factors dominating the performance of the electric double layer capacitors(EDLCs),but their impacts are usually tangled and difficult to decouple and quantitate.Here the effects of electrode meso-macropore structure and solvent polarity on the specific capacitance of an EDLC are quantitatively investigated using a steady-state continuum model.The simulation results indicate the specific capacitances are significantly affected by the meso-macropore surface structure.The specific capacitances significantly decrease for both convex surface structures but obviously increase for both concave surface structures,with the increase of curvature radius from 1 to 20 nm.As for solvents,the polar solvent with high saturated dielectric permittivity improves the capacitance performance.Moreover,the electrode meso-macropore structure is of more concern compared with solvent polarity when aiming at enhancing the specific capacitance.These results provide fundamentals for the rational design of porous electrodes and polar electrolytes for EDLCs.

关键词： Electric doublelayercapacitors Numerical simulation Meso-macropore Electrolytes Saturated dielectricpermittivity

Au/TS-1 catalyst for propylene epoxidation with H_(2)and O_(2):Effect of surface property and morphology of TS-1 zeolite

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Nano Research 2023年第5期16卷 6278-6289页

作者： Jialun Xu Zhihua Zhang Daiyi Yu Wei Du Nan Song Xuezhi Duan Xinggui Zhou State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China

The catalytic performances over propylene epoxidation with H_(2)and O_(2)(HOPO process)are significantly affected by the properties(e.g.,surface properties,Ti coordination,morphology)of titanosilicate zeolite.Introducing urea into zeolite synthesis is a simple and convenient method to modify these properties of titanosilicate zeolite.Uncalcined pore-blocked titanium silicalite-1(TS-1,i.e.,TS-1-B)with the lower urea dosage possesses more defective structure and unsaturated coordinated Ti sites verified by 29Si nuclear magnetic resonance(NMR)and X-ray photoelectron spectroscopy(XPS)analysis,which results in a high initial activity and hydrogen efficiency;while the high surface acidity generated by these Ti species leads to a continuous decrease in the activity and the propylene oxide(PO)selectivity during the reaction.As the amount of urea gradually increases,the TS-1-B samples present the reduced surface defects and defective and unsaturated Ti species.Specially,TS-1-B-0.30U presents the weaker PO adsorption on PO-diffusion reflectance infrared Fourier transform spectra(DRIFTS),thus results in the high stable PO formation rate and selectivity over its Au catalyst.Furthermore,a flat-plate-like shape with a shorter thickness of 100 nm along the b-axis direction is observed on the urea-modified TS-1.Compared with the conventional ellipsoidal TS-1 with crystal sizes of 200 and 500 nm,the flat-plate-like TS-1-0.30U displays the less surface defects,unsaturated Ti species,the weaker Lewis acid,which is favorable for the desorption and intracrystalline diffusion of PO,thus reduces the occurrence of side reactions for the improved selectivity and stability.This work may provide a reference for developing titanium-containing materials with high activity and stability over HOPO reaction.

关键词： propylene epoxidation titanium silicalite-1(TS-1) surface properties Ti species morphological regulation diffusion

Enhanced recycling performance of bimetallic Ir-Re/SiO_(2) catalyst by amberlyst-15 for glycerol hydrogenolysis

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Chinese Journal of Chemical Engineering 2022年第5期35卷 171-181页

作者： Xin Ren Li Leng Yueqiang Cao Jing Zhang Xuezhi Duan Xueqing Gong Jinghong zhou Xinggui Zhou State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Key Laboratory for Advanced Materials Centre for Computational Chemistry and Research Institute of Industrial CatalysisEast China University of Science and TechnologyShanghai 200237China

Recycling performance of heterogeneous catalysts is of crucial importance especially for a batch reaction system.In this work,we demonstrate a strategy for enhancing recycling performance of Ir-Re/SiO_(2) catalyst synergized with amberlyst-15 in glycerol hydrogenolysis to produce 1,3-propanediol.Comprehensive characterization results reveal that the Re sites in the Ir-Re/SiO_(2) catalyst undergo irreversible segregation and oxidation.These hinder the formation of active ReAOH species and thus contribute to a complete and irreversible deactivation.However,the introduction of amberlyst-15 into the reactant mixture can restrain the oxidation process of Re sites and favor the formation of ReAOH species,and thus significantly enhance the catalytic recycling performance.The results demonstrated here could guide the development of excellent bimetallic catalysts with the desirable recycling performances for the reaction.

关键词： Glycerol hydrogenolysis Ir-Re/SiO_(2)catalyst Deactivation mechanism Recycling performance Amberlyst-15 promoter

Production of biomass-derived monomers through catalytic conversion of furfural and hydroxymethylfurfural

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Green Chemical Engineering 2021年第2期2卷 158-173页

作者： hirong Yang Jing Zhang Gang Qian Xuezhi Duan Xinggui Zhou State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai200237China

The synthesis of biomass-derived monomers has received great attention in recent years,motivated by the depletion of fossil fuels and environmental issues.Moreover,the intrinsic functionality within the biomass or biomass-derived chemicals has great potential to produce new types of monomers containing multiple acid or alcohol groups,thereby leading to materials with novel properties.Given their versatile functional groups and easy production from cellulose/hemicellulose,furfural and hydroxymethylfurfural were regarded as very important biomass-derived platform chemicals through which multiple monomers can be produced via heterogeneous catalysis.In the current review,recent development in heterogeneous catalysis for the production of 6 bio-based monomers,furfuryl alcohol,2,5-bis(hydroxymethyl)furan,2,5-bis-(hydroxymethyl)tetrahydrofuran,1,5-pentanediol,1,6-hexanediol,and 2,5-furandicarboxylic acid,from furfural and hydroxymethylfurfural is reviewed and summarized.The major challenge is how to efficiently and selectively convert specific functional group(s)in furfural and hydroxymethylfurfural during the production of these monomers.Additionally,catalyst stability issues need to be addressed due to necessity of using hot water as reaction medium and high tendency of carbonaceous deposit formation on catalyst surface.The current review mainly focuses on efforts of catalytic site design and modification,including selection of metal/support,use of synergy between metal and support,tuning metal size,use of inverse catalysts,adding catalytic promoters,constructing bimetallic sites,etc.,to realize efficient,selective and stable production of bio-based monomers from furfural and hydroxymethylfurfural.

关键词： Biomass-derived monomers Catalyst design Furfural Hydroxymethylfurfural Heterogeneous catalysis

Modeling of propane dehydrogenation combined with chemical looping combustion of hydrogen in a fixed bed reactor

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Chinese Journal of Chemical Engineering 2022年第7期35卷 165-173页

作者： Junru Liu Rui Hu Xinlei Liu Qunfeng Zhang Guanghua Ye Zhijun Sui Xinggui Zhou State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

A redox process combining propane dehydrogenation(PDH)with selective hydrogen combustion(SHC)is proposed,modeled,simulated,and optimized.In this process,PDH and SHC catalysts are physically mixed in a fixed-bed reactor,so that the two reactions proceed simultaneously.The redox process can be up to 177.0%higher in propylene yield than the conventional process where only PDH catalysts are packed in the reactor.The reason is twofold:firstly,SHC reaction consumes hydrogen and then shifts PDH reaction equilibrium towards propylene;secondly,SHC reaction provides much heat to drive the highly endothermic PDH reaction.Considering propylene yield,operating time,and other factors,the preferable operating conditions for the redox process are a feed temperature of 973 K,a feed pressure of 0.1 MPa,and a mole ratio of H_(2) to C_(3)H_(8) of 0.15,and the optimal mass fraction of PDH catalyst is 0.5.This work should provide some useful guidance for the development of redox processes for propane dehydrogenation.

关键词： Propane dehydrogenation Selective hydrogen combustion Simulation Optimization Redox process

Effects of particle shape and packing style on ethylene oxidation reaction using particle-resolved CFD simulation

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Particuology 2023年第11期82卷 87-97页

作者： Yao Shi Hao Chen Wenyao Chen Guanghua Ye Jin Qu Jinbing Li Xinggui Zhou Xuezhi Duan State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai200237China Yanshan Branch of Beijing Research Institute of Chemical Industry China Petroleum&Chemical Company(Sinopec Corp.)Beijing102500China

Gaining in-depth insights into the effects of particle shapes and packing style on ethylene oxidation reaction is of paramount industrial importance.In this work,reactor models of five packing structures with different particle shapes and three packing structures with different packing styles are established by employing software Blender and COMSOL Multiphysics to explore how the reaction-diffusion behaviors affect ethylene oxidation process.The reliabilities of rigid body dynamics model and particle-resolved reactor model are verified by comparing simulated and experimental pressure drops and ethylene conversions.In all the five packing structures with laminar flow conditions,the high bed porosity and low total particle surface area for the trilobe packing structure give rise to the lowest pressure drop of 27.8 Pa/m,while the internal voids cutting mode provides the excellent heat transfer capacity for the Raschig ring packing structure and the highest ethylene conversion and thereby the highest bed temperature rise of 25.1 K for the four-hole cylinder packing structure.Based on these analyses,changing the packing style to the bottom-up Raschig ring-four hole cylinder packing structure would be a good strategy for the effectively lowered reactor temperature rise by 4.8 K together with the slightly reduced ethylene conversion.

关键词： Ethylene oxidation Particle shape Packing style Heat transfer

Kinetics and mechanistic insights into the active sites of Au catalysts for selective propylene oxidation

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Nano Research 2023年第5期16卷 6220-6227页

作者： Qianhong Wang Zhihua Zhang Keng Sang Wenyao Chen Gang Qian Jing Zhang Xinggui Zhou Xuezhi Duan State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

Identification of the catalytically active sites emerges as the prerequisite for an atomic-level comprehensive understanding and further rational design of highly efficient catalysts.Here,we demonstrate a kinetics strategy to identify the active sites of Au catalyst for the disentanglement of geometric and electronic effects on the selective oxidation of propylene to acrolein.Both the Ti-containing titanium-silicalite-1(TS-1)and Ti-free silicalite-1(S-1)were employed as supports to immobilize Au catalysts,which were investigated by a combination of multiple characterization,kinetics analysis,crystal structure modelling.The Au(111)sites are identified as the main active site for acrolein formation,while their electronic effects are highly relevant to the presence or absence of Ti.Moreover,propylene epoxide(PO)formation mainly involves the co-participation of Au and Ti sites,the proximity between Au and Ti sites is found to have less influences on PO formation in a certain distance.In comparison,acrolein is very likely to generate over Au(111)sites via the hydrogen-assisted O_(2) activation to oxygenated species for its oxidizing propylene.The insights gained here could guide the design and preparation of Au catalysts for selective propylene oxidation.

关键词： propylene oxidation Au catalysts active site geometric and electronic effects Au-Ti proximity

碳催化反应:关于氧化脱氢反应的综述(英文)

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催化学报 2014年第6期35卷 824-841页

作者： De Chen Anders Holmen Zhijun Sui Xinggui Zhou Department of Chemical Engineering Norwegian University of Science and Technology N-7491Trondheim Norway State Key Laboratory of Chemical Engineering East China University of Science and Technology Shanghai 200237 China

Carbon mediated catalysis has gained an increasing attention in both areas of nanocatalysis and nanomaterials. The progress in carbon nanomaterials provides many new opportunities to manip-ulate the types and properties of active sites of catalysts through manipulating structures, function-alities and properties of carbon surfaces. The present review focuses on progresses in carbon medi-ated oxidative dehydrogenation reactions of ethylbenzene, propane, and butane. The state-of-the-art of the developments of carbon mediated catalysis is discussed in terms of fundamental studies on adsorption of oxygen and hydrocarbons, reaction mechanism as well as effects of carbon nano-material structures and surface functional groups on the catalytic performance. We highlight the importance and challenges in tuning of the electron density of carbon and oxygen on carbon surfac-es for improving selectivity in oxidative dehydrogenation reactions.

关键词：氧化脱氢反应碳纳米材料纳米催化介导综述材料结构反应机理碳氢化合物