CH4-CO2 Yakıt Karışımının Kombi Yanma Odasında Yanma ve Emisyon Karakteristikleri

Öz

Tarımsal, hayvansal ve atıklardan elde edilebilen biyogaz, ısıtma sistemlerinde doğal gazın yerini alabilir. Bu nedenle yanma özelliklerini incelemek değerli olacaktır. Bu çalışmada doğal gazla çalışan bir ısıtma sisteminde biyogazın yanma özellikleri araştırılmaktadır. Çeşitli CH4- CO2 biyogaz yakıt karışımları 13 ve 31 kW ısıl güç için deneysel ve sayısal olarak analiz edilmiştir. Çalışmanın deneysel kısmında yakıt karışımları kombide yakılarak sıcaklık ve NOX değerleri ölçülmüştür. Çalışmanın sayısal kısmında standart k-ε türbülans modeli ve Eddy Dissipation Concept kullanılmıştır. Sayısal model deneysel verilerle doğrulandı. Sayısal model ile farklı yakıt karışımları için farklı giriş hava sıcaklıklarının ve O2 konsantrasyonunun etkisi de incelenmiştir. Yakıt karışımındaki CO2 miktarı arttıkça alev sıcaklığının doğrusal olarak yaklaşık 1900 K'den 1775 K'ye düştüğü görülmüştür. Yanma ürünündeki NOx konsantrasyonunun yaklaşık 10 ppm'den 2 ppm'nin altına düştüğü görülmüştür. Ayrıca hava ön ısıtmanın ve oksitleyicideki O2 konsantrasyonu değişiminin alev sıcaklıklarını ve NOx değerini önemli ölçüde etkilediği sonucuna varılmıştır.

Anahtar Kelimeler

• Biyogaz
• Yanma
• Kombi
• HAD
• Emisyon

CH4-CO2 Fuel Mixture Combustion and Emission Characteristics in a Combi Boiler Combustor

Öz

Biogas can be obtained from agricultural, animal, and waste, replacing natural gas in heating systems. Because of that, studying its combustion characteristics will be valuable. This study investigates biogas combustion characteristics in a natural gas-powered heating system. Various CH4-CO2 biogas fuel mixtures were analyzed experimentally and numerically for a thermal power of 13 and 31 kW. In the experimental part of the study, the fuel mixtures were burned, and the temperature and the NOX were measured. The standard k-ε turbulence model and Eddy Dissipation Concept were used in the present study's numerical part. The model was validated with the measured data. The modeling results are in agreement with the measurements. Various fuel mixtures were then modeled to seek varying inlet temperature and O2 concentration effects on the combustion characteristics of the biogas fuel mixtures studied. It was concluded that as the amount of CO2 in the fuel mixture was increased the flame temperature decreased linearly from about 1900 K to 1775 K. NOx concentrations in the combustion product decreased from about 10 ppm to below 2 ppm. It was also concluded that air preheating and change in O2 concentration in the oxidizer affected the flame temperatures and NOx considerably.

Anahtar Kelimeler

• Biogas
• Combustion
• Domestic Boiler
• CFD
• Emission

Kaynakça

1. [1] Kecebas A. Gedik E. and Kayfeci M., “The effect of using geothermal energy and natural gas on air pollution arisen from using fossil fuels: Afyon example”, Makine Teknolojileri Elektronik Dergisi, 7(3), 23-30, (2010).
2. [2] Yagli H. and Koc Y., “Determination of Biogas Production Potential from Animal Manure: A Case Calculation for Adana Province”, Cukurova University Journal of the Faculty of Engineering and Architecture, 34(3), pp. 35-48, (2019).
3. [3] Bond T. and Templeton M.R., “History and future of domestic biogas plants in the developing World”, Energy for Sustainable Development, 15:347–354, (2011).
4. [4] Leonov E. and Trubaev P., “The Effect of Biogas Composition on the Characteristics of the Combustion Process”, Diyala Journal of Engineering Sciences, 15, 2, 1–9, (2022).
5. [5] Nonaka, H. O. B. and Pereira F. M., “Experimental and numerical study of CO2 content effects on the laminar burning velocity of biogas”, Fuel, vol. 182, Pages 382-390, (2016).
6. [6] Chan Y. L., Zhu M. M., Zhang Z. Z., Liu P. F., and Zhang D. K., “The Effect of CO2 Dilution on the Laminar Burning Velocity of Premixed Methane/Air Flames”, Energy Procedia, vol. 75, 3048-3053, (2015).
7. [7] Hinton, N. and Stone R., “Laminar Burning Velocity Measurements Of Methane and Carbon Dioxide Mixtures (Biogas) Over Wide Ranging Temperatures and Pressures”, Fuel, 116, 743–750, (2014).
8. [8] Ilbaş, M., Sahin M. and Karyeyen S., “A Numerical Study On Combustion Behaviours Of Hydrogen-Enriched Low Calorific Value Coal Gases”, Int. J. Renewable Energy Research, vol. 6, no.3, (2016).

9. [9] Ma, J., Qi C., Luo S. and Zuo Z., “Numerical Simulation of the Influence of CO2 on the Combustion Characteristics and NOX of Biogas”, Frontiers Energy Research, 9:811037, (2022).
10. [10] Cohé, C., Chauveau C., Gokalp I. and Kurtulus D. F., “CO2 Addition and Pressure Effects On Laminar and Turbulent Lean Premixed CH4 Air Flames”, Proceedings of the Combustion Institute, vol. 32, Issue 2, Pages 1803-1810, (2009).
11. [11] Anggono W., “Experimental and Numerical Investigation of Laminar Burning Velocities of Artificial Biogas Under Various Pressure and CO2 Concentration”, E3S Web of Conferences, 130, 01037, (2019).
12. [12] Lafay Y., Taupin B. and Martins G., “Experimental study of biogas combustion using a gas turbine configuration”, Exp Fluids, 43, 395–410, (2007).
13. [13] Greco A., Mira D. and Jiang X., “Effects of Fuel Composition on Biogas Combustion in Premixed Laminar Flames”, Energy Procedia vol. 105, 1058-1062, (2017).
14. [14] Ghenai C. and Janajreh I., “Combustion of Renewable Biogas Fuels”, Journal of Energy and Power Engineering, 9, 831-843, (2015).
15. [15] Zuo Z., Qi C., Ma J., Sun H., Luo S., Ren D., Zhang Y., Guo J., Cheng Z. and Li C., “Combustion Characteristics of Low Calorific Value Biogas and Reaction Path of NOx Based on Sensitivity Analysis”, Frontiers in Chemistry, 9:830329, (2022).
16. [16] Sahin M., “Investigation of combustion characteristics of biogases obtained from fermentation of organic wastes”, Omer Halisdemir University Journal of Engineering Sciences, Volume 9, Issue 1, 418-428, (2019).
17. [17] Amez I., Castells B., Llamas B., Bolonio D., García-Martínez M. J., Lorenzo J. L., García-Torrent J. and Ortega M., “Experimental Study of Biogas–Hydrogen Mixtures Combustion in Conventional Natural Gas Systems”, Applied Sciences, 11, 6513, (2021).
18. [18] Sahin M., “Combustion characteristics of various biogas flames under reduced oxygen concentration conditions”, Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 41:19, 2415-2427, (2019).
19. [19] Dong W., L. Xiang and J. Gao., “Effect of CO2 dilution on laminar burning velocities, combustion characteristics and NOx emissions of CH4/air mixtures”, Int J Coal Sci Technology, 10, 72, (2023).
20. [20] Devi S., Sahoo N. and Muthukumar, P., “Comparative performance evaluation of a porous radiant burner with a conventional burner: Biogas combustion”, Applied Thermal Engineering, Volume 218, 119338, ISSN 1359-4311, (2023).
21. [21] Cellek M. S., Demir U. and Coskun G., “Investigation effects of different calorific values and operating conditions on biogas flame: a CFD study”, Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 46:1, 8171-8189, (2024).
22. [22] Sahin M., “Analysis of biogas combustion characteristics in conventional burners”, PhD Thesis, Gazi University Institute of Science and Technology, Ankara, (2016).
23. [23] Anetor L., Osakue E. and Odetunde C., “Reduced mechanism approach of modeling premixed propane-air mixture using ANSYS Fluent”, Engineering Journal, vol. 16, Issue 1, (2012).
24. [24] Zandaryaa S. and Buekens A., “Control of Nitrogen Oxides”, Pollution Control Technologies, vol. II. (2014).
25. [25] FLUENT 6. Fluent incorporated. Vol. 2., LEI, (2002).
26. [26] Werle S., “Nitrogen oxides emission reduction using sewage sludge gasification gas reburning process” Ecological Chemistry and Engineering, S 22 (1), 83–94, (2015).
27. [27] Zhou L., Zhang X., Zhong L. and Yu J., “Effects of flame propagation velocity and turbulence intensity on end-gas auto-ignition in a spark ignition gasoline engine”, Energies, 13, 5039, (2020).
28. [28] Alabas H. A. and Ceper B. A., “Effect of oxygen enrichment on the combustion characteristic and pollutant emissions of kerosene-biogas mixtures on a mini jet engine combustion chamber”, Journal of the Energy Institute, 101420, ISSN 1743-9671, (2023).
29. [29] Cellek M. S., “Flameless combustion investigation of CH4/H2 in the laboratory-scaled furnace” International Journal of Hydrogen Energy, vol. 45, Issue 60, ISSN 0360-3199, (2020).