Low load performance of tangentially-fired boiler with annularly combined multiple airflows

A novel burner arrangement scheme with annularly combined multiple airflows (ACMA) was previously proposed for wall-tangentially fired boiler (WTFB), and its superiority over traditional WTFB had been proved. However, coal-fired boilers are often required to play the role of peak-shaving. To this, low load performances of ACMA boiler were investigated in this work to test whether ACMA can still work well under low boiler thermal load (BTL) conditions. Results show that ACMA boiler performance is still better than that of traditional WTFB under low BTL condition, with smaller airflow deflection, improved coal combustion behavior and alleviated thermal deviation on suspended heating surfaces. Besides, NOx emission characteristic of ACMA boiler under low BTL is more desirable. Furthermore, the location of non-service burners has significant effects on coal combustion and heat transfer processes under 440 MW load conditions, and closing the upper burner group is the optimal choice in terms of the comprehensive boiler performance. These findings deepen the understanding of ACMA boiler and provide theoretical and practical guidance in its application in power plants.