f7dc9c6ab1f8c7a 8fcd9532671845f 8fcd9532671845f

شبیه‌سازی CFD هیدرودینامیک راکتور حبابی- دوغابی همزن‌دار تولید ترفتالیک اسید پتروشیمی شهید تندگویان

نوع مقاله: مقاله پژوهشی


دانشکده مهندسی شیمی، دانشگاه علم و صنعت ایران، تهران، ایران


در این مقاله اثر جهت همزن بر رفتار هیدرودینامیکی و نحوه هوادهی اسپارجرهای راکتور واحد ترفتالیک اسید پتروشیمی شهید تندگویان شبیه‌سازی گردیده است. شبیه‌سازی‌ها با رویکرد چندفازی اولرین-اولرین، مدل اغتشاش RNG k-ε به صورت ناپایا، سه بعدی و توسط نرم‌افزار Fluent 6.3.26 انجام گرفت. معادلات حاکم به روش حجم محدود برای تمام دامنه محاسباتی سیستم حل گردید و جهت شبیه‌سازی رفتار همزن در راکتور از مدل قاب چرخان استفاده شد. از آنجائی‌که هوای فشرده از پایین راکتور توسط چهار اسپارجر تزریق می‌شود، نتایج شبیه‌سازی نشان داد، همزن توربینی با جریان بالارونده سبب افزایش زمان ماند حباب‌ها و شدت اختلاط در بالای راکتور می‌شود. همچنین بیشتر انرژی این همزن صرف حرکت سیال شده و مقدار کمی از آن صرف اختلاط فازها می‌شود. برای همزن توربینی با جریان پایین رونده، جریان مایع، گاز خروجی از اسپارجرها را در خلاف جهت منحرف کرده و جریان گاز را به مرکز راکتور هدایت می‌کند.


عنوان مقاله [English]

A CFD Simulation of Agitated Slurry-bubble CTA Production Reactor of Shahid Tondgooyan Petrochemical Complex (STPC)

نویسندگان [English]

  • Sadegh Pahlevani
  • Seyyed Hasan Hashemabadi
  • Amir Heidari
Computational Fluid Dynamic Laboratory, Chemical Engineering Department, Iran University of Science and Technology, Tehran
چکیده [English]

this work, agitated slurry-bubble reactor was simulated with the aid of computational fluid dynamics techniques. The effects of impeller flow direction on hydrodynamic behavior and the aeration quality of reactor spargers (terephthalic acid CTA, production in Shahid Tondgooyan petrochemical complex) were investigated. To this aim, an Eulerian multiphase approach and RNG k-ε turbulence model were employed for large-scale CFD simulations. The results showed that up-flow impeller caused an increase in bubble residence time and mixing intensity in the higher zones of the reactor. Therefore, the length of the liquid path and the number of direction changes were greater in the case of up-flow impeller compared to down-flow one. As a result, the energy associated with the down-flow impeller (at the bottom of reactor) was much higher than the up-flow one; hence the turbulence intensity for the down-flow impeller was also relatively high. For down flow pattern, the outlet gas of spargers caused a reverse flow by the liquid flow and pushed the gas to the reactor center.

کلیدواژه‌ها [English]

  • Agitated Slurry Bubble Reactor
  • Computational Fluid Dynamics (CFD)
  • Pseudo Two-phase Approach
  • RNG k-ε Turbulence Model

[1]. Schallenberg J., En J. H. and Hempel D. C., “The important role of local dispersed phase hold-ups for the calculation of three-phase bubble columns”, Chemical Engineering Science 60, pp. 6027–6033, 2005.

[2]. Swart J. W. A. and Krishna R., “Simulation of the transient and steady state behavior of a bubble column slurry reactor for Fischer–Tropsch synthesis”, Chemical Engineering and Processing 41, pp. 35–47, 2002.

[3]. Nigam K. D. P. and Schumpe A., Three-phase sparged reactors, Gordon and Breach Science Publishers, 1996.

[4]. Murthy B. N., Ghadge R. S. and Joshi J. B., “CFD simulations of gas–liquid–solid stirred reactor: Prediction of critical impeller speed for solid suspension”, Chemical Engineering Science 62, pp. 7184-7195, 2007.

[5]. Panneerselvam R. and Savithri Surender S., G. D., “CFD simulation of hydrodynamics of gas-liquid-solid fluidised bed reactor”, Chemical Engineering Science 64, pp. 1119-1135, 2009.

[6]. Grevskott S., Sanns B. H., Dudukovic M. P., Hjarbo K. W. and Svendsen H. F., “Liquid circulation, bubble size distributions, and solids movement in two-and three-phase bubble columns”, Chemical Engineering Science 51, 1703–1713, 1996.

[7]. Mitra-Majumdar D., Farouk B. and Shah Y. T., “Hydrodynamic modeling of three-phase flows through a vertical column”, Chemical Engineering Science 52, pp. 4485–4497, 1997.

[8]. Jianping W. and Shonglin X., “Local hydrodynamics in a gas–liquid–solid three-phase bubble column reactor”, Chemical Engineering Journal 70, pp. 81–84, 1998.

[9]. Matonis D., Gidaspow D. and Bahary M., “CFD simulation of flow and turbulence in a slurry bubble column”, A.I.Ch.E. Journal 48, pp. 1413–1429, 2002.

[10]. Feng W., Wen J., Fan J., Yuan Q., Jia X. and SunY., “Local hydrodynamics of gas–liquid–nanoparticles three-phase fluidization”, Chemical Engineering Science 60, pp. 6887–6898, 2005.

[11]. Zhang X. and Ahmadi G., “Eulerian–Lagrangian simulations of liquid–gas–solid flows in three-phase slurry reactors”, Chemical Engineering Science 60, 5089–5104, 2005.

[12]. Ljungqvist M. and Rasmuson A., “Numerical simulation of the two phase flow in an axially stirred reactor”,Transactions of the Institution of emical Engineers 79,533, 2001.

[13]. Montante G., Micale G., Magelli F., and Brucato A., “Experiments and CFD predictions of solid particle distribution in a vessel agitated with four pitched blade turbines”, Transactions of the Institution of Chemical Engineers71, 1005–1010, 2001.

[14]. Khopkar A. R., Rammohan A. R., RanadeV. V. and Dudukovic M. P., “Gas–liquid flow generated by a Rushton turbine in stirred vessel: CARPT/CT measurement and CFD simulations”. Chemical Engineering Science 60, 2215, 2005.

[15]. Versteeg H. K. and Malalasekera, W., An introduction to computational fluid dynamics, The finite volume method, Longman Science & Technical, England -> 15, 1995

[16]. FLUENT 6.1, User’s Manual to FLUENT 6.1, Fluent Inc., Centrera Resource Park, 10 Cavendish Court, Lebanon, USA, 2005.

[17]. Spalart P. and Allmaras S., A one-equation turbulence model for aerodynamic flows, Technical Report AIAA 92-0439, American Institute of Aeronautics and Astronautics, 1992.

[18]. Aubin J., Le Sauze N., Bertrand J., Fletcher D. F. and Xuereb C., “PIV measurements of flow in an aerated tank stirred by a down-and an up-pumping axial flow impeller”, Experimental Thermal and Fluid Science 28, pp. 447–456, 2004.