Co-combustion characteristics, interaction and kinetic analysis of multiple coal and eucalyptus

Abstract

Co-combustion of coal and biomass can alleviate the energy crisis and reduce environmental pollution. In this paper, the combustion characteristics of coal (low-calorie Indonesian coal, Shaanxi coal and Datong coal was named LC, SC and TC respectively) with eucalyptus (EU) and their blends (LC, SC and TC blended with EU was named LE, SE and TE respectively) were studied by thermogravimetric analysis (TGA). The results showed that compared with the combustion of coal alone, the comprehensive combustion characteristic index (S) of LE, SE and TE increased by 6.35 %²/min² ℃⁻³, 0.82 %²/min² ℃⁻³ and 0.58 %²/min² ℃⁻³, respectively. With the addition of EU, there was the inhibiting effect of LE and TE, while the promoting effect of SE during the co-combustion. Fourier transform infrared spectrometer (FTIR) was used to analyze functional groups and the results indicated that the main characteristic peaks were CO₂, CO, H₂O, CO and C-H groups during the combustion of the sample. Furthermore, the kinetic parameters were calculated by the Coats-Redfern (C-R) method. The activation energy (E) of LE, SE and TE was 50.61 kJ/mol, 39.92 kJ/mol and 60.77 kJ/mol, respectively. The E of LE was 3.79 kJ/mol higher than that of LC, while the E of SE and TE was 7.27 kJ/mol and 9.49 kJ/mol lower than that of SC and TC, respectively. SC and TC were suitable for co-combustion with EU, especially SC. The results will provide theoretical guidance for the co-combustion of coal and biomass in thermal power plants.