With the increase of the proportion of renewable energy generation

the importance of thermal power units in deep peak load regulation is increasingly prominent

and large-scale load change has become the normal operation. In order to study the deep varying load characteristics of circulating fluidized bed(CFB) unit

this paper takes the supercritical 350 MW CFB boiler of Hepo power plant as the research object

analyzes the variations of bed temperature

steam parameters and pollutant emissions at varying load. The results show that

the bed temperature is positively related to the load

and the bed temperature difference between the front and rear positions is relatively large. The bed temperature can be significantly adjusted by controlling the amount of slag discharged. With the load changing

the temperature of the superheated steam and the reheated steam is generally stable with small fluctuation. When the load is increased and decreased between 60% and 90% of the full load

the variation range of NOx mass concentration emission is 30～70 mg/m3 and 20～50 mg/m3

respectively

due to the reasonable bed temperature and secondary air rate. The original NOx formation at varying load in middle and low load range is significantly greater than that at medium and high load. When participating in deep peak load regulation

the load response speed is faster

the unit load increasing rate is 6 MW/min(1.71%/min)

and the load decreasing rate is 4 MW/min(1.14%/min). Generally

the supercritical 350 MW CFB boiler has the advantages of wide range for variable load

high stability at low load

and lower original NOx emissions.