As a zero-carbon fuel

biomass energy plays an important role in China's energy transition and “carbon neutrality” strategy. Experimental investigation was conducted on straw co-firing based on a supercritical 660 MW unit once through swing tangentially-fired boiler

and the effects of biomass mixing ratio on combustion characteristics

unburned carbon in fly ash

boiler efficiency and cement characteristics were studied. The results showed that

without adding new device

the biomass could be grinded well with the original F-layer pulverizing system and then sent to the burners at the top layer. At 600 MW and 500 MW

when the biomass mixing mass ratio was 11.8%～19.7%(quantity of 30

40

50 t/h)

normal ignition and stable combustion were observed in the furnace

and no advance ignition was detected. The temperature change of flue gas at outlet of the furnace did not exceed 30 ℃. The boiler efficiency maintained at 93.9%～94.1%

and the influence of biomass co-firing on NO_x and SO_2 can be ignored. After biomass co-firing

the 28-day strength activity index of the fly ash was higher than 75%

and other indicators like stability

water demand

specific surface area

stability and bending strength met the standards of building materials.