TIAN Yu1，2,GA0 Mingbin1,XU Shuliang1,YE Mao1
(1.National Engineering Laboratory for Methanol to Olefins,Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023,China;2.University of Chinese Academy of Sciences, Beijing 100049,China)
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 under- standing 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 estab- lished. COMSOL Multiphysics6.0software 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 concentra- tion decreases from the edge of the particle to the middle and core of the particle at 100seconds (s)due to the large concentra- tion difference between inside and outside the catalyst particles,during the diffusion process of methanol molecules into the cata- lyst 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 MToreaction 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 val- ues 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
Get Citation: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.
Received:2023-06-21.Revised:2023-11-19,Online:2023-12-12。
Funding Project:国家自然科学基金项目，编号:22293021,22208337.
First Author:田宇(1998一)，男，硕士生，研究方向为单颗粒传热。E-mail:tianyu@dicp.ac.cn。
Corresponding Author: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。
DOI:10.13732/.ssn.1008-5548.2024.01.007
CLC No:0643.32;TB4 Type Code:A
Serial No:1008-5548(2024)01-0066-13
