Insights on the dual role of low-rank coal with high mineral catalysis index (LRC-HMCI) during blending coal for activated carbon production and low-temperature NH3-SCR of NO

Abstract

The mineral catalysis index (MCI), reflecting the activity of mineral composition in coal, could be used as a meaningful reference to indicate the coal’s application potential. To elucidate the role of low-rank coal with high MCI (LRC-HMCI) on the AC preparation and application, in this investigation, ACs are produced by steam activation after blending Fugu (F) coal, Yangchang (Y) coal and Xiangyuan (X) coal. The as-prepared ACs’ textural evolution and performance were investigated by a series of characterization and low-temperature NO removal tests. The results show that LRC-HMCI promotes the as-prepared AC’s weight loss and burn-off and lowers its yield. The LRC-HMCI could promote the generation of micropores and the transformation from micropores to mesopores/macropores. 6Y-1X-3F-AC’s total BET specific surface area and micropore specific surface area is up to 880 m2/g and 629 m2/g, and the total volume reaches 0.42 cm3/g. LRC-HMCI decreases the AC’s graphitization degree. Meanwhile, LRC-HMCI favors incrementing as-prepared AC’s COO, CO and π–π*. LRC-HMCI also enhances NO removal, and 7Y-1X-2F-AC shows the highest denitrification activity. 2 h’s NO removal rate reaches 45.5%, which is 77.1% higher than 25.7% of Y-AC. The enhanced denitrification is mainly due to the dual role of LRC-HMCI: LRC-HMCI optimizes micropore porosity and improves the surface chemistry properties of AC, which eventually promote the NO and NH3 adsorption; Minerals from LRC-HMCI, particularly Fe-, Ca-, Mg- containing components, could catalyze the NH3-SCR reaction, thus improves the NO removal. The results of this research could guide cost-effective and high-performance AC production through coal blending based on MCI.