Flameless combustion

Experimental and numerical study of the effect of water injection into the reaction zone of a flameless combustion furnace

The effect of water injection on the stability and emissions of a flameless combustion regime was evaluated. Flameless combustion operation was studied without self-regeneration, with self- regeneration, and with combustion air oxygen enrichment. For each case, increasing water flows were injected until the combustion regime was unstable. The evaluation criteria were temperature uniformity and pollutant emissions of species such as carbon monoxide and nitrogen oxide.

Flameless Combustion as an Alternative for Improving the Efficiency of Thermal Systems: State-of-the-Art Review

The increasing energy demand and polluting emissions have generated a growing number of studies into technologies that can be used to mitigate both problems worldwide. Among the alternatives for improving the efficiency of thermal processes, the flameless combustion regime has been presented as one of the most promising options because it enables high thermal performance by enhancing heat transfer and the combustion process, with the consequent reduction in polluting emissions.

Numerical Simulation of a Flameless Combustion Furnace with Mixtures of Methane and a Sub-Bituminous Pulverized Coal

A numerical study of flameless combustion with mixtures of methane and a sub-bituminous pulverized coal was carried out. The analyzed mixtures were 0%, 25%, 50%, 75%, and 100% pulverized coal (energy based). The numerical study was performed using the geometry of a laboratory-scale furnace, which was originally designed to obtain the flameless combustion regime burning natural gas.

Experimental evaluation of a 20 kW oxygen enhanced self-regenerative burner operated in flameless combustion mode

Results are presented on the effects of oxygen enrichment on the performance of a flameless combustion furnace equipped with a regenerative burner. Natural gas was used as fuel (∼97% CH4) and the oxygen concentration in the combustion air was varied from 21% to 35% (volumetric percent). The influence of oxygen enrichment on temperature and species profiles, pollutant emissions, thermal efficiency and regenerators effectiveness was quantified; measures were registered under steady state conditions for average wall temperatures of 880 °C.

Numerical calculation of the recirculation factor in flameless furnaces

 This paper performs calculations of the recirculation factor in simulations of a flameless combustion furnace with different percentages of oxygen in air (from 21% to 100% O2 ). Results are compared with Magnussen’s recirculation theory and show that when there are chemical reactions, the recirculation results are overpredicted. An alternative correlation to Magnussen’s theory is proposed, useful in calculating the recirculation factor in flameless furnaces.

Performance of a Flameless combustion furnace using biogas and natural gas

Flameless combustion technology has proved to be flexible regarding the utilization of conventional fuels. This flexibility is associated with the main characteristic of the combustion regime, which is the mixing of the reactants above the autoignition temperature of the fuel. Flameless combustion advantages when using conventional fuels are a proven fact. However, it is necessary to assess thermal equipments performance when utilizing bio-fuels, which usually are obtained from biomass gasification and the excreta of animals in bio-digesters.