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Cofiring of coal slime in existing utility boilers is a promising approach to the disposal of coal slime. However, reports about cofiring coal slime with anthracite in the down-fired utility boiler are still few. This work presents a comprehensive study on the combustion characteristics, slagging potential, and NOx emissions of cofiring coal slime and anthracite through lab-scale experiments, numerical simulations, and full-scale industrial measurements in a 600MW down-fired utility boiler. The lab-scale experiments show combustion interactions between anthracite and coal slime, which have both a promotive effect on the ignition of anthracite and inhibitive effect on the combustion and burnout of anthracite. Especially, the inhibitive effect is greater than the promotive effect when the blending ratio of coal slime is above 5%. The addition of coal slime can effectively improve the ash fusion temperature of blended samples. In addition, simulations and full-scale industrial measurements of anthracite cofiring with coal slime are performed in a down-fired utility boiler. The results show that as the blending ratio of coal slime increases, the carbon content in fly ash increases and the boiler efficiency and NOx emissions decrease. A 5% ratio is validated to be a reasonable cofiring ratio of coal slime in the actual operation without no slagging phenomenon. These results provide more insights into the cofiring behavior of coal slime and anthracite and guide the application of blending coal slime in a down-fired boiler. [ABSTRACT FROM AUTHOR]

The combustion of a biomass with coal may be one of the most effective methods to improve energy utilisation efficiency. This study aims to investigate the combustion characteristics of distillers' grains with bituminous coal using a thermo‐gravimetric analyser. The results demonstrate that increasing the proportion of distillers' grains in coal results in a reduced ignition temperature (Ti) and burnout temperature (Tb), and activation energy (E) in the combustion stage. Therefore, the comprehensive combustion index (CCI) improves. In an O2/CO2 atmosphere, Ti increased by ∼15°C, while Tb did not change much. However, E and CCI declined relative to an O2/N2 atmosphere. Under the O2/CO2 atmosphere, with an increase in O2 concentration from 10 to 40%, Ti changed over a small range, but Tb declined from 745.8 to 641.4°C, while E and CCI improved. As the heating rate rose from 10 to 30°C/min, the values of Ti decreased (from 281.4 to 244.9°C), but the values of Tb increased significantly (from 662.8 to 745.8°C); the value of E reduced, and CCI also improved. This research could provide useful information as a practical reference for heat and power production. [ABSTRACT FROM AUTHOR]