Study on combustion characteristics of fully premixed water-cooled biogas burner

Abstract

Biogas is a renewable gas produced by the fermentation of biomass and is an environmentally friendly alternative to traditional fossil fuels. To overcome the problems of traditional biogas burner, such as unstable combustion, easy flameout and backfire, and low thermal intensity, a new water-cooled biogas burner based on fully premixed combustion technology was designed and developed. Then, numerical simulations and experimental investigations were conducted to explore the effects of CO2 content, excess air coefficient, heat load, and cooling water temperature on the combustion characteristics of the burner. The results revealed that the designed burner exhibited good adaptability to simulated biogas with methane concentrations ranging from 55 % to 80 %. Increasing CO2 content resulted in decreased combustion temperatures and reduced NOx and CO emissions concentration at the burner outlet. In addition, reducing the excess air coefficient enhanced the combustion heat intensity and reduced combustion heat loss. Nevertheless, excessively low excess air coefficients yielded elevated levels of NOx and CO in the flue gas. The results showed that the designed burner demonstrated stable operation at a minimum heat load of 35 %, exhibited a favorable load regulation ratio, and had low emissions. It is a promising solution for utilizing biogas as a clean and sustainable energy source.