田宇^1,2，高铭滨¹，徐庶亮¹，叶茂¹

（1. 中国科学院大连化学物理研究所，甲醇制烯烃国家工程实验室，辽宁大连116023；2. 中国科学院大学，北京100049）

引用格式:

田宇，高绪滨，徐庶亮，等。黏结剂对甲醇制烯烃中单票粒催化别内部反应过程的影响J.中国粉体技术，2024.30(1):66-78.

TIAN Y,CA0 M B,XU S L,et al.Effects of binden on intermal reaction process of single particle catalys inmetharol to alefin D.China Pomder Scienceand Technolog,2024,30(1):66-78.

DOI:10.13732/.ssn.1008-5548.2024.01.007

收稿日期:2023-06-21.修回日期:2023-11-19,上线日期:2023-12-12。

基金项目:国家自然科学基金项目，编号:22293021,22208337.

第一作者简介:田宇(1998一)，男，硕士生，研究方向为单颗粒传热。E-mail:tianyu@dicp.ac.cn。

通信作者筒介:叶茂(1973-),男，研究员，博士，国家高层次人才特殊支持计划领军人才，博士生导师，研究方向为工业过程开发、多相反应器与流动、多相催化与传递、人工智能及机器学习等。E-mail:maoye@dicp.ac.cn。

摘要:【目的】以甲醇制烯烃(methanol to olefins,MTO)为代表的非均相催化反应在现代化学工业中占据着重要的地位，研究MTO过程中单颗粒催化剂的反应、传质与传热过程，有助于系统理解催化反应机理、优化催化剂设计，实现工艺升级。【方法】建立单颗粒催化剂颗粒模型、反应动力学模型以及传质与传热模型；采用COMSOLMuitiphysics6.0软件模拟MTO反应过程，分别由二氧化硅、氧化铝和高岭土作为黏结剂，建立3种SAPO-34分子筛催化剂颗粒模拟模型:分析3种催化剂颗粒内甲醇扩散和温度传导过程，分析黏结剂对酸性位点、多甲基苯和多甲基萘的浓度分布的影响，将催化剂肤粒内部的传热、传质过程与化学反应进行糈合。【结果】甲醇分子向催化剂颗粒内部的扩散过栏中，在t100 s时甲醇浓度分布基本稳定，从颖粒边缘处向中部、枝心处甲醇浓度依次减小；以二氧化硅为黏结剂的顺粒在中心处、边缘处的热力学温度分别为656、627K,鞭粒内部的甲醇扩散速度最快；在MTO反应过程中，3种颗粒内，为热力学温度均为由中心向边绿处选戏:随着MTO反应时间的增加，3种住化剂题粒的酸性位点浓度平均值逐渐减小，多甲基苯、多甲基养的浓度平均值逐渐增大:以二氧化硅为黏结剂的粒边缘处的的酸性位点浓度降幅最大，然后依次是颗粒的中部和枝心处，颖粒内多甲基萘的分布更均匀。【结论】以二氧化硅为黏结剂的催化剂颗粒内部温度最高、温升录快，有效促进了MTO反应的进行，有利于颗粒内分子惨的充分利用和多甲基苯和多甲基萘的均匀分布。

关键词:甲醇制烯烃；黏结剂；单颗粒催化剂；反应动力学；传质；传热

Abstract

Objective Heterogeneous catalytic reactions, such as Methanol to olefins(MTO),play an important role in the modern chemical industry. The study of reaction kinetics, mass and heat transfer of single-particle catalyst in the MTO process is helpful to understanding catalytic reaction mechanism, optimizing catalyst design and realizing process upgrading.

Methods The particle model,reaction kinetics model and mass and heat transfer model of single-particle catalyst were established. COMSOL Multiphysics 6.0 software was used to simulate the MTO reaction process, and the SAPO-34 zeolite catalyst particle model was established with silica, alumina and kaolin as binders,respectively. The methanol diffusion and temperature conduction processes within the catalyst particles were analyzed. The influences of binders on the concentration distribution of acid sites,polymethylbenzene and polymethylnaphthalene were studied,and the heat and mass transfer in catalyst particles were coupled with the chemical reaction.

Resuits and Discussion The methanol quickly diffuses into the catalyst particles at the initial stage,and the methanol concentration decreases from the edge of the particle to the middle and core of the particle at 100seconds (s)due to the large concentration difference between inside and outside the catalyst particles,during the diffusion process of methanol molecules into the catalyst particles. The highest methanol concentration is foundinside the particles with silica as a binder,so the binder silica has the greatest influence on the diffusion of methanol in the catalyst particles.During the MTO reaction process,the thermodynamic temperature distribution inside the three kinds of particles decreases from the center to the edge. The reaction temperature inparticles with silica as the binder is the highest, and the thermodynamic temperature within the particles reaches the highest values at 100s, which are656K at the center and 627K at the edge of the particles, respectively. The usage of silica as the binder for catalyst particles is more conducive to promoting the reaction within the particles. With the increase of MTO reaction time, the average acidic sites concentration of the three catalyst particles gradually decreases, and the particles with silica as the binder have the fastest decreasing rate, and the acidic sites concentration at the edge of the catalyst particles decreases the most. The average polymethylbenzene concentration of the three catalyst particles increases gradually,with the lowest average polymethyl- benzene concentration in the particles used silica-based binder and the fastest polymethylbenzene concentration at the edge. The concentration of polymethylnaphthalene within the three catalyst particles increasesgradually,and the distribution of polymethy1- naphthalene within the particles is more uniform using silica as the binder.

Conclusion Conclusion The mass and heat transfer processes inside catalyst particles formed by three kinds of binders and the influence of their chemical reaction processes are studied by numerical simulation. It is found that the MT0 reaction in silica particles is more fully carried out, which exhibits more utilization efficiency of acid sites and more uniform carbon deposition distribution, compared with other particles.

Keywords:methanol to olefin; binder; single particle catalyst; reaction kinetics;mass transfer;heat transfer

参考文献( References):

[1]TIAN P, WEI Y X, YE M, et al, Methanol to olefins (MTO) : from fundamentals to commercialization[J]. ACS Catalysis2015，5(3):1922-1938.

[2]YE M, LI H, ZHA0 Y F, et al. MTO processes development; the key of mesoscale studies[J]. Advances in Chemical Engineering，2015,47:279-335.

[3]DAHL I M,KOLBOE S. On the reaction mechanism for hydrocarbon formation from methanol over SAPO-34; 2. isotopiclabeling studies of the co-reaction of propene and methanol[ J]. Journal of Catalysis, 1996, 161(1): 304-309.

[4]OLSBYE U,SVELLE S,BJORCEN M, et al. Conversion of methanol to hydrocarbons; how zeolite cavity and pore size controls pruduct selectivity[J]. Angewandte Chemic-Intemational Edition in English, 2012, 51(24): 5810-5831.

[5]SVELLE S,JOENSEN F,NERLOV J, et al. Conversion of methanol into hydrocarbons over zeolite H-ZSM-5: etheneformation is mechanistically separated from the formation of higher alkenes Jl. Journal of the American Chemical Society.2006，128(46): 14770-14771.

[6] WANC S, CHEN Y Y,WEl Z H,et al. Polymethylbenzene or alkene cycle theoretical study on their contribution to theprocess of methanol to olefins over H-ZSM-5 zeolitelJl. The Joural of Physical Chemistry C,2015, 119(51); 28482-28498.

[7]MARTfNEZ-ESPIN J S,DE WISPELAERE K,JANSSENS T V W,et al. Hydrogen transfer versus methylation; on the genesis of aromatics formation in the methano-to-hydrocarbons reaction over H-ZSM-5[J]. ACS Catalysis, 2017, 7(9).5773-5780.

[8]HAW J F,MARCUS D M.Well-defined ( supra)molecular structures in zeolite methanol-to-olefin catalysis[J]. Topics inCulalysis，2005，34(1/2/3/4):41-48.

[9]YARULINA 1, KAPTEJN F,CASCON J. The importance of heat efects in the methanol to hydrocarbons reaction over ZSM-5: on the role of mesoporosity on catalyst performance[ J]. Catalysis Science and Technology, 2016, 6( 14): 5320-5325

[10]SIMEONE M,SALEMME L, ALLOUIS C, et al. Temperature profile in a reverse flow reactor for catalytic partial oxidationof methane by fast IR imaging[J]. AICE Journal，2008，54(10): 2689-2698.

[11]KIMMERLE B,CRUNWALDT J-D, BAIKER A, et al Visualizing a catalyst at work during the ignition of the catalyticpartial oxidation of methane[J]. The Journal of Physical Chemistry C; Nanomaterials and Interfaces , 2009, 113(8):3037-3040.

[12]OIAN Q Y, VOCT C, MOKHTAR M, et al. Combined operando UV/Vis/IR spectroscopy reveals the role of methoxy andaromatic species during the methanol-to-olefins reaction over H-SAPO-34[J]. ChemCatChem, 2014,6( 12): 3396-3408.

[13]BORODINA E,SHARBINI HARUN KAMALUDDIN H，MEIRER F,el al, nuence he reaclin leperalure on ltnature of the active and deactivating species during methanol-o-olefins conversion over H-SAPO-34[J] ACS Catalysis.2017，7(8): 5268-5281.

[14]CAO M B, LI H, LIU W ], et al. maging spatiotemporal evolution of molecules and active sites in zeolite catalyst duringmethanol-to-olefins reaction[J]. Nature Communications，2020，11(1): 3641.

[15]CAO M B, LI H, YANC M,et al. Direct quantification of surlace barriers for mass transfer in nanoporous crystallinematerials[J]. Communications Chemistry，2019，2( 1):813-821.

[16]HENDRIKS F C,MEIRER F,KUBAREV A V,et al. Single-molecule fluorescence microscopy reveals local diffusioncoefficients in the pore network of an individual catalyst particle[ J]. Journal of the American Chemical Society, 2017.139(39): 13632-13635.

[17]BUURMANS IL C, RUIZ-MARTINEZ , KNOWLES W V, et al. Catalytic activity in individual cracking catalyst particlesimaged throughout diferent life stages by selective staining[J]. Nature Chemistry, 2011, 3(11): 862-867.

[18]COSTA P,SANDRIN D,SCAANO J C. Rea-time fluorescence imaging of a heterogeneously catalysed Suzuki-Miyaurareaction[J].Nature Catalysis，2020，3(5): 27-437.

[19]FU D L,ERIK MARIS J J,TANCIAKOVA K,et l. Unraveling channel structure-difusivity relationships in zeoliteZSM-5 at the single-molecule level[ J]. Angewandte Chemie International Edition, 2021,61(5): e202114388.

[20]QIAN Y,RUIZ-MARTINEZ J, MOKHTAR M,et al.Single-particle spectroscopy of alcohol-to-olefins over SAPO-34 atdifferent reaction stages: crystal accessibility and hydrocarbons reactivity[J]. ChemCatChem, 2014,6(3): 772-783.

[21]LI H, YE M, LIU Z M.A multi-region model for reaction-diffusion process within a porous catalyst pellet[J]. ChemicalEngineering Science，2016，147: 1-12.

[22]VANSPEYBROECK V,HEMELSOET K,DEWISPELAERE K,t al. Mechanistic studies on chabazite-type methano-to-olcfin catalysts; insights from timc-resolved UV/VIS microspectroscopy combincd with theoretical simulations[ J]. Chem-CatChem，2013，5(1):173-184.

[23]WHITINC C T,NIKOLOPOULOS N,NIKOLOPOULOS 1, et al Visualizing pore architecture and molecular transportboundaries in catalyst bodies with fluorescent nanoprobes[J]. Nature Chemistry,2018, 11(1): 23-31.

[24] YUAN X S, LI H,YE M,et al. Kinetic modeling of methanol to olefins process over SAPO-34 catalyst based on the dualcycle reaction mechanism[J]. AIChE Journal，2019，65(2):662-674.