Analysis of Fuel Properties for Fifty Kinds of Typical Alternative Fuels

With CO₂ generation and emissions requirements, the cement industry faces huge pressure for reducing carbon emissions. Choosing alternative fuels instead of coal is a promising approach. However, the fuel properties of the alternative fuels have not been comprehensively studied. In this work, the fifty typical alternative fuels were selected based on the compositions for different classifications, and the basic fuel properties including proximate analysis, ultimate analysis, and low calorific values were analyzed. Most fuels from plastics and clothes have relatively low moisture; the values of as-received basis moisture (M_ar) and air-dry basis moisture (M_ad) of the others are all lower than 30 wt%. However, the alternative fuels of plastic and cloth all have relatively high contents of air-dry basis volatile compounds (V_ad) (>60 wt%), and they all have low contents of air-dry basis fixed carbon (FC_ad) (commonly <20 wt%) and air-dry basis ash (A_ad) (<30 wt%). The air-dry basis carbon contents (C_ad) of plastics are higher than 40 wt%, while the C_ad values of biomass are lower than 50 wt%. As for air-dry basis hydrogen (H_ad), the contents are all lower than 14 wt% and relatively stable for different kinds of alternative fuels. As for air-dry basis nitrogen (N_ad), the contents are all lower than 9 wt%, and most of them are lower than 3 wt%. In addition, the contents of air-dry basis sulfur (S_ad) of different alternative fuels are also lower than 3 wt%, while plastics, biomass, and clothes are all lower than 1 wt%. Also, the low calorific values (Q_net,ar) for the alternative fuels of plastic are commonly high, and the values for biomass are commonly between 500 and 1500 kJ/kg, while Q_net,ar values for the alternative fuels of cloth and others vary. The fuel properties of the fifty typical alternative fuels can guide fuel selection and optimization when they are mixed for combustion with coals in cement decomposition furnaces.