MILD OXY-COMBUSTION OF PROPANE IN A MESOSCALE TURBULENT BURNER

The present study investigates the characteristics of MILD combustion in a (20x20x5cm) laboratory-scale burner (Fig. 1a-b). The main pre-heated flow rate, composed by diluent and oxygen, and the fuel are fed inside the combustion chamber from one side. Diametrically opposed the feeding configuration is reproduced, thus realizing a spiral flow field inside the combustion chamber. The system is provided with a quartz window. The oxidation process of fuels/oxygen mixtures diluted in N2, CO2 (oxy-fuel processes) or steam can be studied varying external parameters of the system, namely inlet temperatures (up to 1400K), equivalence ratio (from fuel lean to reach mixtures), residence times and mixture dilution levels. Temperature measurements inside the chamber and gas sampling/analysis at the stack are realized. Rapid mixing between the injected fuel and hot oxidizer has been carefully explored for autoignition of the mixture to achieve volumetric combustion reactions. Distributed reactions can be achieved for a non-premixed configuration with sufficient entrainment of hot species present in the flame and their rapid turbulent mixing with the reactants. Preliminary tests, realized for C3H8/O2 mixtures diluted in N2, showed that for inlet temperatures higher than 900 K, MILD combustion condition is established. Fig. 1-c shows the in-furnace view for several operative conditions up to MILD combustion regime (Fig. 1-c-3) where propane oxidation process occurs in an invisible and homogeneous manner. Figure 1. Images showing the in-furnace appearance of propane combustion. 10.4405/profic2014.