NUMERICAL ANALYSIS OF 330 MWth ÇAN POWER PLANT CIRCULATING FLUIDIZED BED BOILER BY COMPUTATIONAL PARTICLE FLUID DYNAMIC METHOD

Öz

CFBB (Circulating Fluidized Bed Boiler) systems that is foregoing as efficiency and enviromental combustion of the low quality lignites that have %88 in the Turkish lignites. In the present study, Çan TS numerical analysis were conducted by CPFD(Computational Particle Fluid Dynamics) method with it was reached that boundary conditions and geometrical knowledges of the Çan TS CFBB system by otomation and control room. Pressure, temperature, O₂, CO₂, H₂O and SO₂ mole fraction changing in the combustion chamber were investigated in the numerical analysis. In the study results, pressure, temperature, O₂, CO₂, H₂O and SO₂ mole fraction of the bottom of the furnace is relatively 108401 Pa, 1093 K, 0,01, 0,04, 0,077, 0,005 and pressure, temperature, O₂, CO₂, H₂O and SO₂ mole fraction of the exit of the furnace is relatively 103347 Pa, 1015 K, 0,081, 0,05, 0,049, 0,003. It is showed that very good compliance with numerical and practical results.Also, important emissions and particule hydrodynamic flow are modelled with combustion and pressure properties by improved mathematical model. It is showed that, mathematical model that is improved by CPFD method will have great benefits in modeling studies. As a result of the study,it is showed that optimizable of the small and large capacity(0,5-100 MW_th) of the CFBB systems with CPFD method using validated numerical model.

Anahtar Kelimeler

• Circulating fluidized bed boiler,Computational Particle Fluid dynamics,Combustion,Particle hydrodynamic flow,Numerical analysis

330 MWth ÇAN DOLAŞIMLI AKIŞKAN YATAKLI TERMİK SANTRAL KAZANININ HESAPLAMALI PARTİKÜL AKIŞKANLAR DİNAMİĞİ METODUYLA SAYISAL ANALİZİ

Öz

Son yıllarda Türkiye linyitlerinin %88’ini oluşturan düşük kaliteli linyitlerin temiz ve verimli bir şekilde yakılabilmesini sağlayan en önemli yakma teknolojisi olarak CFBB (Dolaşımlı Akışkan Yataklı Kazan) sistemleri öne çıkmaktadır. Bu çalışmada, çalışır durumda ve 330 MW_th kapasitesindeki ÇTS (Çan Termik Santrali) CFBB sistemine ait otomasyon odasından alınan sınır koşulları ve yanma odası geometrik parametreleri dikkate alınarak, CPFD (Hesaplamalı Partikül Akışkanlar Dinamiği) metodu yardımıyla sistemin sayısal analizi gerçekleştirilmiştir. Analizlerde, yanma odasındaki basınç, sıcaklık, O₂, CO₂, H₂O ve SO₂ mol oranlarındaki değişimler incelenmiştir. Elde edilen analiz sonuçlara göre,  ÇTS kazan tabanındaki basıncın 108401 Pa,   sıcaklığın 1093 K, mol oranları ise O₂ için  0,01,  CO₂ için 0,04, H₂Oiçin 0,077  ve SO₂ için 0,005 olduğu gözlemlenirken, kazan çıkışındaki ise sıcaklığın 1015 K, mol oranlarının O₂ için  0,08,  CO₂ için 0,05, H₂O için 0,049 ve  SO₂ için 0,003 olduğu görülmüştür. Sunulan çalışmada kapsamında,, pratik sonuçlarla oldukça uyumlu olduğu sayısal sonuçlar elde edilmiştir. Gerçekleştirilen matematiksel modellemede, yanma ve basınç özelliklerinin yanı sıra önemli emisyonlar ve partikül hidrodinamik akışı da modellenmiştir. Bu durum da CPFD metoduyla geliştirilen matematiksel modelin,akışın ve yanma prosesinin modellenmesinde çok büyük kolaylık oluşturduğunu göstermiştir. CPFD metoduyla doğrulanan sayısal model kullanılarak, 0,5-100 MW_th arasında değişen farklı kapasitede CFBB sistemlerinin tasarımları ve sınır koşullarının  optimize edilebileceği sonucuna ulaşılmıştır.

Anahtar Kelimeler

• Dolaşımlı akışkan yataklı kazan,Hesaplamalı partikül akışkanlar dinamiği,Yanma,Partikül hidrodinamik akışı,Sayısal analiz

Kaynakça

1. AB LCP Direktifi, 2001. The Large Combustion Plant Directive LCPD, 2001/80/EC, Erişim Tarihi: 28.07.2015. http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32001L0080.
2. Batchelor, G.K., 1988. A New Theory of the Instability of a Uniform Fluidized Bed. Journal of Fluid Mechanics, 193, 75–110.
3. Borgwardt, R.H., Bruce, K.R., Blake, J., 1987. An Investigation of Product-Layer Diffusivity for CaO Sulfation. Industrial and Engineering Chemistry Research, 26(10), 1993-1998.
4. Chen, J.,Yao, H., Zhang, L., 2012, A Study on the Calcination and Sulphation Behaviour of Limestone During Oxy-fuel Combustion. Fuel, 102, 386-395.
5. CPFD Barracuda User Guide, 2015.
6. Dennis, J.S.,Hayhurst, A.H., 1990. Mechanism of the Sulphation of Calcined Limestone Particles in Combustion Gases. ChemEngSci, 45, 1175–1187.
7. Ducarne, E.D., Dolignier, J.C., Marthy, E., Martin, G., Delfosse, L., 1998. Modelling of Gaseous Pollutants Emissions in Circulating Fluidized Bed Combustion of Municipal Refuse. Fuel 77, 1399-1410.
8. Duo, W., Dam-Johansen, K.,Ostergaard, K.,1992. Kinetics of the Gas Phase Reaction Between Nitric-Oxide, Ammonia and Oxygen. Canadian Journal of Chemical Engineering, 70(5), 1014-1020.

9. Farid, M.M., Jeong, H.J., Kim, K.H., Lee, J., Kim, D., Hwang, J., 2017. Towards a Hybrid Eulerian–Lagrangian CFD Modeling of Coal Gasification in a Circulating Fluidized Bed Reactor, Fuel, 152, 131–137.
10. Feng, Y.,Swenser-Smith, T., Witt, P.J., Doblin, C., Lim, S., Schwarz M.P., 2012. CFD Modeling of Gas-Solid Flow in an Internally Circulating Fluidized Bed. PowderTechnology, 219, 78-85.
11. Gan, J., Zhou, Z., Yu, A., 2016. Particle Scale Study of Heat Transfer in Packed and Fluidized Beds of Ellipsoidal Particles. Chemical Engineering Science, 144, 201–215.
12. Gasparini, F., Papa, I., Criner, K., Mary, S., Coal Oxy-Combustion in a CHP Plant Using the Circulating Fluidized Bed (CFB) BoilerTechnology, PowerGen Europe, 12-14 June 2012, Colon, Germany. http://www.fwc.com/getmedia/e3c64ca2-e558-4b77-ba3d e77306bbcea7/TP_CFB_12_09.pdf.aspx?ext=.pdf.
13. Gidaspow, D., 1994. Multiphase Flow and Fludization Continuum and Kinetic Theory Description. Academic Press, Boston.
14. Gungor, A., & Eskin, N. 2008. Two-dimensional Coal Combustion Modeling of CFB. International Journal of Thermal Sciences, 47(2), 157-174.
15. Gül, S., Özdoğan, Z.S., 2016. Ejector Type Solid Circulation System Analysis for Circulating Fluidized Beds. International Journal of Multiphase Flow, 84, 116–128.
16. Jiang Y.,Qiu G., Wang H., 2014. Modelling and Experimental Investigation of the Full-Loop Gas-Solid Flow in Circulating Fluidized Bed with Six Cyclone Separators. Chemical Engineering Science, 109, 85-97.
17. Johnsson, J.E., Dam-Johansen, K.,1991. Formation and Reduction of in a Fluidized Bed Combustor. 11th International Conference on Fluidized Bed Combustion, ASME, 1389-1396.
18. Karimipour, S., Pugsley, T., 2012. Application of the Particle in Cell Approach for the Simulation of Bubbling Fluidized Beds of Geldart a Particles. Powder Technology, 220, 63-69.
19. Kilpinen, P.,Kallio, S., Konttinen, J., &Barišić, V. 2002. Char-nitrogen Oxidation Under Fluidised Bed Combustion Conditions: Single Particle Studies. Fuel, 81(18), 2349-2362.
20. Kraft, S., Kimbauer, F., Hofbauer, H., 2017. CPFD Simulations of an Industrial-sized Dual Fluidized Bed Steam Gasification System of Biomass with 8 MW Fuel Input. Applied Energy, 190, 408.
21. Ku Shaari, Ku.Z., Awang, M., 2015. Engineering Applications of Computational Fluid Dynamics. VIII, 167, 108, Hardcover, ISBN: 978-3-319-02835-4.
22. Liu, H., Feng, B., Lu, J.D., 2005. Coal Property Effects on N2O and NOX Formation from Circulating Fluidized Bed Combustion of Coal, Chemical Engineering Communications, 192, (10–12), 1482–1489.
23. Özkan, M., 2010. Simulation of Circulating Fluidized Bed Combustors Firing Indigenous Lignite. Master Thesis, Orta Doğu Teknik Üniversitesi Fen Bilimleri Enstitüsü, 134s, Ankara.
24. Pandey, K.M., Kumar, R., 2011. Numerical Analysis of Coal Combustion in Circulating Fluidized Bed. International Journal of Chemical Engineering and Applications, 2(6), 390-394.
25. Smagorinsky, J., 1963. General Circulation Experiments with the Primitive Equations, part I: the Basic Experiment, Monthly Weather Review, 91, 99-164.
26. Weng, M.,Plackmeyer, J., 2011. Comparison Between Measurements and Numerical Simulation of Particle Flow and Combustion a the CFBC Plant. 10th International Conference on Circulating Fluidized Beds And Fluidization Technology (CFB-10), 3-5 Spring 2011, Duisburg. http://dc.engconfintl.org/cfb10/61/
27. Williams, F.A., 1985. Combustion Theory, Benjamin/Cummings, Menlo Park, California, 2nd Edition.
28. Yang, N.,Wang, W., Ge, W., Wang, L., &Li, J. 2004. Simulation of Heterogeneous Structure in a Circulating Fluidized-Bed Riser by Combining the Two-Fluid Model with the EMMS Approach. Industrial & Engineering Chemistry Research, 43(18), 5548-5561.
29. Yang, Wen-Cin, 2003. Handbook of Fluidization and Fluid-ParticleSystem. Marcel Dekker, The NewYork, (a) p267 and (b) p2 62.