Abstract




 
   

IJE TRANSACTIONS C: Aspects Vol. 31, No. 9 (September 2018) 746-755    Article in Press

downloaded Downloaded: 0   viewed Viewed: 318

  TRANSIENT ENTROPY GENERATION ANALYSIS DURING WUSTITE PELLET REDUCTION TO SPONGE IRON
 
A. Zare Ghadi, M. S. Valipour and M. Biglari
 
( Received: July 28, 2017 – Accepted: January 23, 2018 )
 
 

Abstract    The present study carefully examined entropy generation during wustite pellet reduction to sponge iron. The finite volume method was used to solve the governing equations. The grain model was used to simulate the reaction rate. The reactant gases including carbon monoxide and hydrogen are converted to water and carbon dioxide after wustite reduction. Entropy is generated by heat transfer, mass transfer and chemical reactions. The entropy generated by these processes was discussed in the relevant sections. Based on the governing equations, the share of each process in the generation of entropy was calculated. The effects of gas ratio, porosity, and tortuosity and grain diameter of wustite pellet on entropy generation were investigated. According to the results, porosity and gas ratio were inversely proportional to the rate of entropy generation while tortuosity and grain diameter were directly proportional to entropy generation rate.

 

Keywords    Wustite Pellet, Entropy Generation, Mathematical Model, Grain Model

 

چکیده    در کار حاضر تولید آنتروپی در طول فرایند احیای گندله وستیتی به آهن اسفنجی مورد مطالعه قرار گرفته است. روش حجم محدود برای حل معادلات حاکم استفاده شده است. مدل دانه‏ای برای شبیه‏سازی نرخ واکنش مورد استفاده قرار گرفته است. پس از اتمام فرایند احیای وستیت گازهای احیا شامل مونوکسیدکربن و هیدروژن به آب و دی کسیدکربن تبدیل می‏شوند. آنتروپی از طریق انتقال حرارت، انتقال جرم و واکنش‏های شیمیایی تولید می‏شود. بر اساس معادلات حاکم، سهم هر فرایند در تولید آنتروپی محاسبه شده است. تاثیرات نسبت گاز، تورچیاسیتی و قطر دانه وستیتی بر روی تولید آنتروپی بررسی شده است. بر طبق نتایج، تخلخل و نسبت گاز رابطه عکس با نرخ تولید آنتروپی دارد در حالیکه تورچیاسیتی قطر دانه با نرخ تولید آنتروپی رابطه مستقیم دارد.

References    1. Valipour M. S. and Mokhtari M. H., \"Effect of Water Gas Shift Reaction on the Non-Isothermal Reduction of Wustite Porous Pellet Using Syngas\", International Journal ISSI, Vol. 8, No. 2, (2011), 9-15. 2. von Bogdandy L. and Engell, H. J., \"The reduction of iron ores\", Springer Verlag, (1971). 3. McKewan W. M., \"Influence movement during high pressure reaction of hematite by hydrogen\", Journal of Metals, Vol. 16, (1964), 781–802. 4. Turkdogan E. T. and Vinters J. V., \"Gaseous reduction of iron oxides: part I. Reduction of hematite in hydrogen, Metal Transaction\", Vol. 2, (1971), 3175–3188. 5. Usui T., Ohmi M. and Yamamura E., \"Analysis of rate of hydrogen reduction of porous wustite pellets basing on zone reaction models\", ISIJ International, Vol. 30, (1990), 347–355. 6. Valipour M. S. and Khoshandam B., \"Numerical modelling of non-isothermal reduction of porous wustite pellet with syngas\", Ironmaking Steelmaking, Vol. 36, No. 2, (2009), 91-96. 7. Szekely J., Evans J.W., Sohn H.Y., \"gas-solid reactions\", Academic Press, (1976). 8. Valipour M. S., Hashemi M. Y. M. and Saboohi Y., \"Mathematical modeling of the reaction in an iron ore pellet using a mixture of hydrogen, water vapor, carbon monoxide and carbon dioxide: an isothermal study\", Advance Powder Technology, Vol. 17, No. 3, (2006), 277-295. 9. Hirschfelder J.O., Curtiss C.F., Bird R.B., \"Molecular Theory of Gases and Liquids\", Wiley, (1954). 10. Bejan A., \"Advanced Engineering Thermodynamics\", Wiley, (1988). 11. Bejan A., \"Second law analysis in heat transfer\", Energy, Vol. 5, (1980), 721–732. 12. Bejan A., \"Entropy Generation through Heat and Fluid Flow\", Wiley, (1982). 13. Bejan A., \"The thermodynamic design of heat and mass transfer processes and devices, International Journal of Heat and Fluid Flow\", Vol. 8, (1987), 258–276. 14. San J.Y. , Worek W.M., Lavan Z., \"Entropy generation in convective heat transfer and isothermal convective mass transfer\", Transaction of the ASME, Journal of Heat Transfer, Vol. 109, (1987), 647–652. 15. Arpaci V.S., Selamet A., \"Entropy production in flames\", Combustion and Flame, Vol. 73, (1988), 251–259. 16. Dash S.K., Som S.K., \"Transport processes and associated irreversibilities in droplet combustion in a convective medium\", International Journal of Energy Research, Vol. 15, No. 7, (1991), 603–619. 17. Puri I.K., \"Second law analysis of convective droplet burning\", International Journal of Heat and Mass Transfer, Vol. 35, No. 10, (1992), 2571–2578. 18. Hiwase S., Datta A., Som S.K., \"Entropy balance and exergy analysis in the process of droplet combustion\", Journd of Physics D. Applied Physics, Vol. 3, (1998), 1601–1610. 19. Pope D.N., Raghavan V., Gogos G., \"Gas-phase entropy generation during transient methanol droplet combustion\", International Journal of Thermal Sciences 49, (2010), 1288-1302. 20. Shamsi, M., and SA Gandjalikhan Nassab. \"Ivestigation of entropy generation in 3-d laminar forced convection flow over a backward facing step with bleeding.\" International Journal of Engineering-Transactions A: Basics, Vol. 25, No. 4, (2012), 379. 21. Ziapour, B. M., and F. Rahimi. \"Numerical study of natural convection heat transfer in a horizontal wavy absorber solar collector based on the second law analysis.\" International Journal of Engineering-Transactions A: Basics, Vol. 29, No. 1, (2016): 109. 22. Versteeg H.K. and Malalasekera W., \"An Introduction to Computational Fluid Dynamics: The Finite Volume Method\", John Wiley & Sons, Inc., (1995). 23. Hara Y., Sakawa M. and Kondo S., \"Mathematical model of the shaft furnace for reduction of iron ore pellet\", Tetsu-to-Hagane, Vol. 62, (1976), 315-323. 24. Valipour M.S., \"Mathematical Modeling of a Non-Catalytic Gas-Solid Reaction: Hematite Pellet Reduction with Syngas\", Scientica Iranica, Vol. 16, No. 2, (2009), 108-124.  25. Ghadi, A.Z., Valipour, M.S. and Biglari, M.,. \"Mathematical modelling of wustite pellet reduction: grain model in comparison with USCM\". Ironmaking & Steelmaking, Vol. 43, No. 6, (2016), 418-425.





International Journal of Engineering
E-mail: office@ije.ir
Web Site: http://www.ije.ir