Using bi-reforming of methane in natural gas burners: A novel environmentally friendly method for enhancement of thermal properties of flame

Abstract

A novel interesting method based on bi-reforming of methane was proposed for improvement of flame thermal characteristics and radiation heat flux (RHF) in natural gas (NG) furnaces. In the proposed plan, bi-reforming was done by recirculation of the flue gas. The recirculated flue gas which dominantly including CO₂ and H₂O and inert gas N₂ mixed with a certain part of NG flow and the mixture passed through an array of nickel based catalysts placed inside a helical tube mounted in the furnace wall to bi-reforming process is done. Gasses mixture temperature of 800°C, p = 1 atm and the ratio of CH₄/(CO₂ + H₂O) = 0.8 were the proposed bi-reforming condition. The results indicated that in the proposed bi-reforming condition, significant portion of CH₄ and CO₂ converted to H₂ and CO. The CH₄ and CO₂ conversion were 98.47% and 81.18% while the yield of H₂ and CO as the target reaction products were 94.40% and 93.38%, respectively. Bi-reforming changed the NG flame from blue to a yellow luminous. Furthermore, since the methane adiabatic flame temperature at p = 1 atm is greater than that of for hydrogen, H₂ generated by bi-reforming combusted inside the combustion reaction zone and raises the flame temperature. Both enhance the flame temperature and luminosity raises RHF as much as 30%. Finally, although the bi-reforming slightly increases the NO_x emission, it decreases the total amount of flue gas emission to environment, which makes the method environmentally friendly.