Sentez gazı-metan karışımlarının ön karışımsız türbülanslı yanmasının azot oksit emisyonlarına etkisi üzerine sayısal bir çalışma

Yıl 2024, Cilt: 14 Sayı: 4, 1098 - 1109, 15.12.2024

Suat Öztürk

https://doi.org/10.17714/gumusfenbil.1262009

Öz

Sunulan çalışmada, biyokütlenin gazlaştırılması ile üretilen sentez gaza farklı oranlarda metan eklenmesi ile elde edilen karışımların türbülanslı yanması sonunda azot oksitlerin emisyonlarındaki değişimler farklı şartlar altında sayısal olarak incelenmiştir. Simülasyonlar, ön karışımsız yakıt/hava karışımı jet alevleri için gerçekleştirilmiştir. Adyabatik olmayan alev sıcaklıkları ve emisyonlar ANSYS programı kullanılarak hesaplanmıştır. Alev sıcaklıkları ve yakıcı çıkışında azot oksitlerin salımlarının, hidrojen/karbon monoksit-metan karışımı içindeki metan miktarının artması ile azaldığı saptanmıştır. %50 metan eki, azot oksitlerin salımınını %58.9 düşürmektedir. Artan basıncın azot oksitlerin emisyonlarını artırdığı ve bu artışın metan oranının yükselmesi ile azaldığı belirlenmiştir. Azot oksitler, 7 bar basınçta %202.8 yükselmektedir. Tüm yakıt karışımları için, hem giriş havası hem de yakıcı duvar sıcaklıklarındaki artış alev sıcaklığını ve azot oksitlerin üretimini artırdığı tespit edilmiştir. Giriş sıcaklığının 100 K yükseltilmesi azot oksitlerin salımınını %14.4 artırmaktadır. Yakma havası içindeki nem oranının artmasının azot oksitlerin oluşumunu düşürdüğü ve yakma havası içinde karbon dioksit seyreltmesinin azot oksitlerin salınımlarını azalttığı belirlenmiştir. Karbon dioksit seyreltmesinde %5 artış, azot oksitlerin salımınını %63 düşürmektedir.

Anahtar Kelimeler

Azot oksitler, Ön karışımsız, Sentez gazı, Türbülans, Yanma

A numerical study on the effect of non-premixed turbulent combustion of synthesis gas-methane mixtures to nitrogen oxide emissions

Öz

In the presented study, changes in nitrogen oxides emissions at the end of turbulent combustion of mixtures obtained by methane addition at several ratios to synthesis gas produced by gasification of biomass are numerically investigated under different conditions. Simulations are performed for non-premixed fuel/air mixtured jet flames. Temperatures and emissions of non-adiabatic flames are calculated using ANSYS program. It is determined that flame temperatures and nitrogen oxides emissions at the outlet of the combustor decrease with increase of methane amount in hydrogen/carbon dioxide-methane mixture. 50% addition of methane reduces nitrogen oxides emissions 58.9%. It is specified that raising pressure increases nitrogen oxides emissions and this increment is reduced by ascending of methane ratio. Nitrogen oxides rises 202.8% at 7 bar pressure. It is detected that increment at temperatures of both inlet air and the wall of the combustor enhances flame temperature and nitrogen oxides production for all the fuel mixtures. Increase of 100 K at inlet temperature raises nitrogen oxides emission 14.4%. It is designated that increase of humidty ratio in burning air reduces nitrogen oxides formation and carbon dioxide dilution in the burning air decreases nitrogen oxides emissions. 5% increase at carbon dioxide dilution decreases nitrogen oxides emission 63%.

Anahtar Kelimeler

Combustion, Nitrogen oxides, Non-premixed, Synthesis gas, Turbulence

Kaynakça

• Asgari, N., & Padak, B. (2018). Effect of fuel composition on NOx formation in high-pressure syngas/air combustion. AIChE Journal, 64(8), 3134-3140. https://doi.org/10.1002/aic.16170
• Barbato, P. S., Landi, G., & Russo, G. (2013). Catalytic combustion of CH4-H2-CO mixtures at pressure up to 10 bar. Fuel Processing Technology, 107, 147-154. http://dx.doi.org/10.1016/j.fuproc.2012.08.024
• Canlı, E., Ateş, A., & Bilir, Ş. (2020). Derivation of dimensionless governing equations for axisymmetric ıncompressible turbulent flow heat transfer based on standard k-ϵ model. AKU J. Sci. Eng., 20, 1096-1111. https://doi.org/ 10.35414/akufemubid.821009
• Cardona, C., Amell, A., & Burbano, H. (2013). Laminar burning velocity of natural gas/syngas-air mixture. Dyna, 180, 136-143.
• Cheng, T. S., Chang, Y. C., Chao, Y. C., Chen, G. B, Li, Y. H., & Wu, C. Y. (2011). An experimental and numerical study on characteristics of laminar premixed H2/CO/CH4/air flames. International Journal of Hydrogen Energy, 36, 13207-13217. https://doi.org/10.1016/j.ijhydene.2011.07.077
• Chouaieb, S., Kriaa, W., Mhiri, H., & Bournot, P. (2016). Presumed pdf modeling of microjet assisted CH4-H2/Air turbulent flames. Energy Conversion and Management, 120, 412-421. http://dx.doi.org/10.1016/j.enconman.2016.05.003
• Chun, K. W., Chung, H. J., Chung, S. H., & Choi, J. H. (2011). A numerical study on extinction and NOx formation in nonpremixed flames with syngas fuel. Journal of Mechanical Science and Technology, 25(11), 2943-2949. https://doi.org/10.1007/s12206-011-0810-4
• Effiong, E. E., Orga, A. C., Ibe, E. C. & Ekeke, I. C. (2015). Model for the transient flow of natural gas through a pipelıne in two dimensional cylindrical coordinates-Part I. International Journal of Current Research, 7, 11, 22367-22370.
• Guo, H., Smallwood, G. J., Liu, F., Ju, Y., & Gülder, Ö., L. (2005). The effect of hydrogen addition on flammability limit and nox emission in ultra-lean counterflow CH4/air premixed flames. Proceedings of the Combustion Institute, 30, 303-311. https://doi.org/10.1016/j.proci.2004.08.177
• Hwang, J., Sohn, K., Bouvet, N., & Yoon, Y. (2013). NOx scaling of syngas H2/CO turbulent non-premixed jet flames. Combustion Science and Technology, 185(12), 1715-1734. https://doi.org/10.1080/00102202.2013.831847
• Liu, Y., Xue, Q., Zuo, H., Yang, F., Peng, X., & Wang, J. (2021). Effects of CO2 and N2 dilution on the combustion characteristics of H2/CO mixture in a turbulent partially premixed burner. ACS Omega, 6, 15651-15662. https://doi.org/10.1021/acsomega.1c00534
• Mohammadi, M. H. (2018). Numerical Analysis of fluid flow and heat transfer based on the cylindrical coordinate system. Fluid Mechanics, 4(1), 1-13. https://doi: 10.11648/j.fm.20180401.11
• Morovatiyan, M., Shahsavan, M., Baghirzade, M., & Mack, J. H. (2019). Effect of hydrogen and carbon monoxide addition to methane on laminar burning velocity. Proceedings of the ASME 2019 Internal Combustion Engine Division Fall Technical Conference (ICEF) (pp. 20-23), Chicago. https://doi.org/10.1115/ICEF2019-7169
• Murakami, Y., Nakamura, H., Tezuka, T., Asai, G., & Maruta, K. (2021). Reactivity of CO/H2/CH4/Air mixtures derived from ın-cylinder fuel reformation examined by a micro flow reactor with a controlled temperature profile. Combustion Science and Technology, 193(2), 266-279. https://doi.org/10.1080/00102202.2020.1847096
• Othman, N. F. & Boosroh, M. H. (2016). Effect of H2 and CO contents in syngas during combustion using micro gas turbine. International Conference on Advances in Renewable Energy and Technologies (ICARET) (pp. 1-5). https://doi.org/10.1088/1755-1315/32/1/012037
• Ozturk, S. 2021. CFD study for NOx formation in turbulent jet flames with syngas fuel. Global Conference on Engineering Research (Globcer) (pp. 2-5), Bandırma.
• Park, S., & Kim, Y. (2017). Effects of nitrogen dilution on the NOx formation characteristics of CH4/CO/H2 syngas counterflow non-premixed flames. International Journal of Hydrogen Energy, 42, 11945-11961. http://dx.doi.org/10.1016/j.ijhydene.2017.02.080
• Peng, S. F., Davidson, L., & Holmberg, S. (1996). The two-equation turbulence k-w model applied to recirculating ventilation flows. Chalmers University of Technology, 96, 13, 1-25. Tabet, F., Sarh, B., & Gökalp, I. (2009). Hydrogen–hydrocarbon turbulent non-premixed flame structure. International Journal of Hydrogen Energy, 34, 5040-5047. https://doi.org/10.1016/j.ijhydene.2008.12.083
• Tran, M. V., Scribano, G., Chong, C. T., Ng, J. H., & Ho, T. X. (2019). Numerical and experimental study of the ınfluence of CO2 dilution on burning characteristics of syngas/air flame. Journal of the Energy Institute, 92, 1379-1387. https://doi.org/10.1016/j.joei.2018.09.004
• Samiran, N. A., Ng, J. H., Jaafar, M. N. M., Valera-Medina, A., & Chong, C. T. (2016). H2-rich syngas strategy to reduce NOx and CO emissions and improve stability limits under premixed swirl combustion mode. International Journal of Hydrogen Energy, 41, 19243-19255. http://dx.doi.org/10.1016/j.ijhydene.2016.08.095
• Shih, H. Y., & Hsu, J. R. (2013). Dilution effects analysis of opposed-jet H2/CO syngas diffusion flames. Combustion Theory and Modelling, 17(3), 543-562. http://dx.doi.org/10.1080/13647830.2013.782069
• Stylianidis, N., Azimov, U., & Birkett, M. (2019). Investigation of the effect of hydrogen and methane on combustion of multicomponent syngas mixtures using a constructed reduced chemical kinetics mechanism. Energies, 12(2442), 1-23. https://doi.org/10.3390/en12122442
• Williams, T. C., Shaddix, C. R., & Schefer, R. W. (2007). Effect of syngas composition and CO2-diluted oxygen on performance of a premixed swirl-stabilized combustor. Combustion Science and Technology, 180(1), 64-88. https://doi.org/10.1080/00102200701487061
• Wu，H., & Zhang, W. (2008). Combustion characteristics of hydrogen-methane hybrid fuels in coflow jet diffusion flames. Proceedings of ASME Turbo Expo 2008: Power for Land, Sea and Air (GT2008) (pp. 9-13), Berlin.
• Zeldovich, Y. B. (1946). The oxidation of nitrogen in combustion and explosives. Acta Physicochimica USSR, 21, 577.
• Ziani, L., Chaker, A., Chetehouna, K., Malek, A., & Mahmaha, B. (2013). Numerical simulations of non-premixed turbulent combustion of CH4/H2 mixtures using the pdf approach. International Journal of Hydrogen Energy, 38, 8597-8603. http://dx.doi.org/10.1016/j.ijhydene.2012.11.104