Numerical and experimental study of natural gas preheating effects on the soot formation, flame luminosity and NO emission

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Abstract

In this paper, the effect of inlet gas temperature on the soot content, flame temperature and overall efficiency of a 120 kW boiler have been investigated. For modeling the impact of inlet gas temperature on combustion and soot production, a non-premixed turbulent model was employed. Besides, using the Reynolds turbulent stress model, stress terms in momentum equations were solved. Also, Moss-Brooks model and a beta probability density function (β-PDF) is used to describe the effect of turbulencies on soot formation. Moreover, experiments were conducted on a boiler which its inlet gas temperature is preheated with a Chrome-Nickel electric heater. The results demonstrate that the preheating of natural gas up to about 510 K has no considerable effect on the flame luminosity. Otherwise, preheating the inlet fuel up to 700 K increases the flame soot content up to 3 times resulting in a serious luminosity rise. This increase causes a reduction in flame temperature (150K) and NO emission. It is seen that the predicted results have good agreement with measurements.

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References

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Journal of Solid and Fluid Mechanics
Volume 7, Issue 1
March and April 2017
Pages 79-90

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