Effect of Hot-Pressing Process on the Strength of Biomass Carbon-Containing Pellets

The hot-pressing biomass carbon-containing pellets uses clean resources with zero carbon emissions as raw materials, which is conducive to energy conservation and emission reduction, and reduces greenhouse gas carbon dioxide emissions. Corn stalk was used as raw material for pyrolysis treatment, and studies the effects of pyrolysis temperature and pyrolysis time on the recovery rate and fixed carbon through single-factor experiment. The preparation of new furnace burden hot-pressing biomass carbon-containing pellets was studied. The study investigates the effect of preparation factors on its compressive strength using the Taguchi method, further calculating the contribution of each factor to compressive strength, and obtaining the optimal preparation parameters for hot-pressing biomass carbon-containing pellets. The effect of the type and addition amount of binder on the compressive strength of hot-pressing biomass carbon-containing pellets was also studied. The experimental results show that the appropriate conditions for biomass pyrolysis are pyrolysis temperature of 400 °C, pyrolysis time of 60 min, with the recovery rate of 38.15%, and fixed carbon content of 56.73%, suitable for preparing hot-pressing biomass carbon-containing pellets. Among the four influencing factors of C/O ratio, hot-pressing temperature, hot-pressing pressure, and hot-pressing time, hot-pressing pressure has the greatest effect on compressive strength, with a contribution rate of 44.46%. The optimized preparation parameters for hot-pressing biomass carbon-containing pellets are the C/O ratio of 1.0, hot-pressing temperature of 450 °C, hot-pressing pressure of 40 MPa, and hot-pressing time of 3 min. The average compressive strength of the hot-pressing biomass carbon-containing pellets reached 1178.96N. By adding 5% organic binder, the compressive strength of the hot-pressing biomass carbon-containing pellets was increased to 2389N, meeting the requirements for blast furnace smelting.