Research and application of online monitoring of coal and biomass co-combustion and biomass combustion characteristics based on combustion flame

Compared with the contact and offline flame monitoring methods, the online flame monitoring method does not interfere with the measurement site and can reflect the combustion status of fuel in real time. It is of great significance to protect the safety of combustion equipment, improve the combustion efficiency and optimize. The main purpose of this review is to explain the online monitoring methods and applications of co-combustion of coal and biomass and pure biomass combustion flame. Three online monitoring methods, flame image processing, electrical signal analysis, and spectral analysis are summarized. Compared with the pulverized coal combustion flame, the differences in geometric, thermodynamic, and luminous characteristics of coal and biomass co-combustion flame are analyzed. Then the applications of these three methods in biomass combustion stability monitoring, temperature measurement, fuel identification, pollutant emission characteristics, and prediction are summarized. •This review article is carried out from a perspective that has not been written about before.•This paper summarizes the recent research progress.•This review article provides a comparative analysis of different monitoring methods.•This review article enriches the research and can bring some guidance and inspiration to the reader.•This review summarizes the online monitoring of alkaline pollutants from biomass combustion.