Investigating the Effect of Flow Rate Changes on Flare Performance Using Computational Fluid Dynamics Modeling(CFD)

Document Type : Review

Authors

1 Department of Chemical Engineering, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran

2 null2 Department of Chemical Engineering, Faculty of Engineering, Arak University, Arak 38156-8-8349, Iran

Abstract

Computational Fluid Dynamics (CFD) is a good numerical tools to solve complicated equations like fluid flows, heat transfer and chemical reactions such as flares issue. In this study, the effect of a changes in the flow rate on flare performance of one of Iran's oil refineries in actual mass flowrate range of 4,000 pounds per hour was calculated using CFD modeling, with Ansys Fluent software 16.0. Also its geometry and mesh designing were carried out by Gambit software 2.4.6. To investigate the effect of changes in flow rate on the flame temperature, flame length, profile of the concentration of combustion species and the turbulent stream pattern in the flame The related calculations are 2D in terms of axis symmetry in which the turbulence was modeled by standard k-ε, Non Premixed Combustion models, Simple Algorithm based on basic pressure and steady state condition were applied and also neglected the effects of the wind. By aid of independant variables from mesh, for actual mass flow ranges, we chose 68700 cells. The simulation results showed that although by changing the mass flow rate, in the range of 4000 pounds per hour does not change the maximum flame temperature. But changes the altitude that happens in this temperature. The length of flame varied in following situation, real mass flow was 14.9 meter which by %10 changes in mass flow, the length displaced 0.66 meter. Therefore, the rate of k (turbulence kinetic energy), ε (loss kinetic energy) increased by increasing the mass flow rate. The distribution of hydrogen and methane constituents in the range of the flame is equal to 1% molar and, with increasing massflow rate both distribution widespread and range of distribution of water and carbon dioxide is 5 and 10%, respectively both Concentrations increased by increasing the mass flow rate.

Keywords

Main Subjects


[1] Raj Alphones, Kader Rasel, Vijaya Damodara, Daniel Chen, Helen Lou, & Peyton Richmond, “Better Plant Start up via Simulation”, Presentation in the Alche National meeting, San Fransisco, CA, November 12-17, 2006.
[2] Anderson, John David, and J. Wendt. Computational fluid dynamics. Vol. 206. New York: McGraw-Hill, 1995.
[4] Baukal C.E., J.R., Gershtein V.Y. and Li Xianming, “Computational Fluid Dynamics in Industerial Combustion”, CRC Press LLC, Boca Raton, FL, 2001.
]4[ صباغ، رضا، رهبر، نادر، «بررسی تاثیر شکل هندسی بر بیشینه دمای جداره ی نوک فلر و توزیع آلاینده‌های خروجی آن»، مجله مدل‌سازی در مهندسی، سال سیزدهم، شماره 40، بهار 1394.
[5] Singh, Kanwar Devesh, Preeti Gangadharan, Daniel H. Chen, Helen H. Lou, Xianchang Li, Peyton Richmond, "Computational fluid dynamics modeling of laboratory flames and an industrial flare", Journal of the Air & Waste Management Association 64, no. 11, 2014, pp: 1328-1340.
[6] Jatale, A., P. Smith, J. Thornock, and S. Smith, "A validation of flare combustion efficiency simulations". American Flame Research Committee, Salt Lake City, UT. 2012.
[7] Kanwar Devesh Singh, Tanaji Dabade, Hitesh Vaid, Preeti Gangadharan, Daniel Chen, Helen H. Lou, Xianchang Li, Kuyen Li, and Christopher B. Martin, “Computational Fluid Dynamics Modeling of Industrial Flares Operated in Stand-By Mode”, Industrial & Engineering Chemistry Research, October 2012.
[8] David. Castineira, and Thomas F. Edgar, “CFD for Simulation of Crosswind on the Efficiency of High Momentum Jet Turbulent Combustion Flames”, Journal of Enviromental Engineering © ASCE, July 2008, pp: 561.
[9] Johnson, M. R., and Kostiuk, L. W. “Efficiencies of lowmomentum jet diffusion flames in crosswinds Combust," Flame, 2000, Vol. 123, pp: 189–200.
[10] Kostiuk, Larry, Matthew Johnson, and Glen Thomas. "University of Alberta Flare Research Project: final report November 1996-September 2004. 2.", 2004.
[11] David Castiñeira, Thomas F. Edgar, Computational Fluid Dynamics for Simulation of Wind-Tunnel Experiments on Flare Combustion Systems, Energy Fuels, 2008, 22 (3), pp 1698–1706
[12] David. Castineira," Computational Fluid Dynamics for Simulation Model for Flare Analysis and Control" The University of Texas at Austin, 2006.