Simulation of Fluidized Bed Reactor Using Computational Fluid Dynamics in the Process of Methanol Conversion to Light Olefins; Kinetic Modeling Study

Document Type : Research Paper

Authors

1 Department of Chemical Engineering, Faculty of Engineering, University of Qom, Iran

2 Department of Energy Engineering, Faculty of mechanical engineering, Qom University of Technology, Iran

Abstract

Over the past decade, catalytic methanol-to-olefin conversion has been among the most highly developed processes for light olefin production. In this study, computational fluid dynamics (CFD) and COMSOL software were used to investigate the process of methanol conversion to light olefins. The Eulerian-Eulerian model was used to solve continuous and scattered phase flows. A simplified kinetic model was used for methanol conversion to olefin, including a catalyst effect, coke deposition, and the finite element method used to solve the equations. MATLAB software was used to obtain the kinetic parameters of the methanol to olefin process using a kinetic model and a genetic algorithm. A comparison was made between the experimental results and the proposed model for the main products, which showed a good agreement. For ethylene, propylene, and butene, the mean relative error was 2.40%, 1.35%, and 3.11%, respectively. Following the model validation, various parameters such as solid-phase distribution in the bed, velocity vectors, particle size, bed pressure drop, and average mass fraction of the components are investigated on reactor performance. Examining the solid phase distribution in the bed at various input velocities and times revealed that the solid concentration in the whole bed is almost dilute in the Ergun drag model. The flow structure appears generally homogeneous. By studying the particle size effect on velocity vectors, it is found out that as particle diameter increased, the turbulence of flow vectors increased and the number of vortices forming in the bed increased. Furthermore, the average mass fraction of hydrocarbons achieved during reactor output increased. Moreover, the methanol conversion reached more than 90%.
 

Keywords


[1]. Sedighi M, Mohammadi M (2020) CO2 hydrogenation to light olefins over Cu-CeO2/SAPO-34 catalysts: Product distribution and optimization, Journal of CO2 Utilization, 35:  236-244. ##
[2]. Basilio E, Babadagli T (2020) Testing the injection of air with methane as a new approach to reduce the cost of cold heavy oil recovery: An experimental analysis to determine optimal application conditions, Fuel, 265:  116954. ##
[3]. Mazari S A, Hossain N, Basirun W J, Mubarak N M, Abro R, Sabzoi N, Shah A (2020) An overview of catalytic conversion of CO2 into fuels and chemicals using metal organic frameworks, Process Safety and Environmental Protection, 149:  67-92. ##
[4]. Hu D, Ordomsky V V, Khodakov A Y (2021) Major routes in the photocatalytic methane conversion into chemicals and fuels under mild conditions, Applied Catalysis B: Environmental, 119913. ##
[5]. ahmadpour S, Yaripour F, Khorasheh F (2018) Construction of HZSM-5 zeolite in medium containing fluoride ion and its performance in the conversion of methanol to propylene, Journal of Petroleum Research, 28: 17-28. ##
[6]. Shirazi L, Gangji E, Taheri z (2013) The effect of H-SAPO-34 template type on conversion of methanol to light olefins, Journal of Petroleum Research, 21: 44-53. ##
[7]. Sedighi M, Ghasemi M, Sadeqzadeh M, Hadi M (2016) Thorough study of the effect of metal-incorporated SAPO-34 molecular sieves on catalytic performances in MTO process, Powder Technology, 291: 131-139. ##
[8]. Kaeding W W, Butter S A (1975) Conversion of methanol and dimethyl ether, United States, US3911041A. ##
[9]. Sedighi M, Towfighi J (2015) Methanol conversion over SAPO-34 catalysts; Systematic study of temperature, space–time, and initial gel composition on product distribution and stability, Fuel, 153: 382-392. ##
[10]. Kaiser S W (1987) Production of light olefins, United States, US4677242A. ##
[11]. Marchi A, Froment G (1991) Catalytic conversion of methanol to light alkenes on SAPO molecular sieves, Applied Catalysis, 71: 139-152. ##
[12]. Inui T, Phatanasri S, Matsuda H (1990) Highly selective synthesis of ethene from methanol on a novel nickel–silicoaluminophosphate catalyst, Journal of the Chemical Society, Chemical Communications, 205-206. ##
[13]. Zhang C, Wang F, Lu B, Wang W, Liu M, Lu C (2020) Numerical exploration of hydrodynamic features in a methanol-to-olefins fluidized bed reactor with two parallel reaction zones, Powder Technology, 372:  336-350. ##
[14]. Xu T, Jiang X, Yang N, Zhu J (2015) CFD simulation of internal-loop airlift reactor using EMMS drag model, Particuology, 19:  124-132. ##
[15]. Zhang M, Chu K, Wei F, Yu A (2008) A CFD–DEM study of the cluster behavior in riser and downer reactors, Powder Technology, 184:  151-165. ##
[16]. Tsuji T, Yabumoto K, Tanaka T (2008) Spontaneous structures in three-dimensional bubbling gas-fluidized bed by parallel DEM–CFD coupling simulation, Powder Technology, 184: 132-140. ##
[17]. Chang J, Zhang K, Chen H, Yang Y, Zhang L (2013) CFD modelling of the hydrodynamics and kinetic reactions in a fluidised-bed MTO reactor, Chemical Engineering Research and Design, 91:  2355-2368. ##
[18]. Zhuang Y-Q, Chen X-M, Luo Z-H, Xiao J (2014) CFD–DEM modeling of gas–solid flow and catalytic MTO reaction in a fluidized bed reactor, Computers and Chemical Engineering, 60: 1-16. ##
[19]. Lu B, Zhang J, Luo H, Wang W, Li H, Ye M, Liu Z, Li J (2017) Numerical simulation of scale-up effects of methanol-to-olefins fluidized bed reactors, Chemical Engineering Science, 171: 244-255. ##
[20]. Soanuch C, Korkerd K, Phupanit J, Piemjaiswang R, Piumsomboon P, Chalermsinsuwan B (2021) Computational fluid dynamics simulation of methanol to olefins in stage circulating fluidized bed riser: Effect of reactor stage parameters on product yields, Korean Journal of Chemical Engineering, 38: 540-551. ##
[21]. Wen M, Ding J, Wang C, Li Y, Zhao G, Liu Y, Lu Y (2016) High-performance SS-fiber@ HZSM-5 core–shell catalyst for methanol-to-propylene: a kinetic and modeling study, Microporous and Mesoporous Materials, 221:  187-196. ##
[22]. Mohammadi M, Sedighi M (2013) Modification of Langmuir isotherm for the adsorption of asphaltene or resin onto calcite mineral surface: Comparison of linear and non-linear methods, Protection of Metals and Physical Chemistry of Surfaces, 49: 460-470. ##
[23]. Yang M, Fan D, Wei Y, Tian P, Liu Z (2019) Recent progress in methanol‐to‐olefins (MTO) catalysts, Advanced Materials, 31: 1902181. ##