Co-combustion kinetic analysis of biomass hydrochar and anthracite in blast furnace injection

In this paper, the physicochemical and co-combustion properties of hydrochar and anthracite were studied in detail. The results showed that the property of the hydrochar was equivalent to the low rank coal, and the C/H ratio reached 2.1, which was lower than the anthracite. The structural results revealed that compared with the hydrochar, the anthracite had higher graphitization degree due to its high coalification. From the co-combustion experiments, with the increase of hydrochar mixing ratio, the ignition temperature and burn-out temperature were decreased, and the combustibility can be improved. Kinetic analysis indicated that the random pore model had the best calculation effect, and results of activation energy decreased first and then increased. As the mixing ratio was 60%, the activation energy of mixed fuel was the lowest, indicating that 60% was the best ratio. The corresponding activation energy values of two mixtures were 45.84 KJ/mol and 55.05 KJ/mol, respectively. Thus, the addition of hydrochar can effectively improve the combustion efficiency of mixed fuel. Regarding the environmental benefit, the calculation result showed that the emission reduction were 143.2 kg/tHM and 145.7 kg/tHM, respectively, indicating that hydrochar was a green fuel for blast furnace injection.