Pressure Analysis of the Initial Process of Diffusion Combustion Surge in a 350 kW Gas Boiler
In order to meet the increasingly stringent requirements for nitrogen oxides (NOx) emissions from gas boilers, flue gas recirculation (FGR) technology is commonly used to achieve ultra-low NOx emissions. However, under some ultra-low NOx combustion conditions with FGR, a surge phenomenon occurs in the boiler, which causes a flameout in severe cases, and seriously affects the safe and stable operation of the boiler. In this study, the diffusion combustion surge of gas boiler with a rated power of 350 kW and equipped with FGR device was investigated. Pressure characteristic analysis results of the initial process of combustion surge showed that the high-frequency component of pressure is closely related to combustion stability and its change can provide reference for the occurrence of surge. Besides, the initial process of surge was analyzed by wavelet packet entropy method. Results indicated that the wavelet packet entropy of pressure signals could effectively reflect the stability of combustion in the furnace, and it could also be used to study the occurrence of surge.