Experimental study of flame stability enhancement on lean premixed combustion of a synthetic natural gas in Thailand

An experimental study was done of the intrinsic instability of flames and flame stability enhancement burning two types of Thai natural gas. They were studied using a McKenna flat burner and a ceramic porous burner. The effects of the equivalence ratio and firing rate using various combinations of fuels and burners on the flames were studied. Gas combustion using a McKenna flat burner revealed that the eastern natural gas had a more stable flame with a smaller cell size and a wider cellular flame flammability limit than the western natural gas. In contrast, the ceramic porous burner produced two distinct flame types depending on the equivalence ratio. These were a surface stabilized flame with strong thermal radiation emitted by the burner surface to the surroundings at relatively rich combustion, 0.9 <= Phi <= 1.0 and a conventional cellular free flame at relatively lean combustion 0.75 <= Phi <= 0.8, where the ceramic porous burner transforms the surface stabilized flame into conventional cellular flame structures. The ceramic porous burner can extend the flame stability limit of the western natural gas up to Phi = 0.75 with no flame flashback and flame blow-off. This can make a ceramic porous burner suitable for household cooking despite the lower fuel quality of western natural gas. (C) 2019 Elsevier Ltd. All rights reserved.