Development of high temperature oxidation resistant iron-based heat storage materials for rapid carbonization and pulverization process of biomass

Utilization of the solid phase transformation heat of the iron-based alloy as well as its sensible heat was proposed as a Heat Storage Materials, HSM, for the rapid carbonization and pulverization process of biomass. Aluminizing of the HSM is a promising way to improve focused to improve its high temperature oxidation resistance. In this study, behavior of solid phase transformation and high temperature oxidation behavior, and wear and impact resistances of the oxide layer are examined for Fe-Mn-C alloy as a candidate of HSM. Latent heats and transformation temperatures were evaluated using a DSC. Mass change ratio of the samples were measured using a TG. Then, DSC measurements were carried out with the oxidized samples. Spherical segment samples were charged into lab-scale rotary kiln type furnace to evaluate wear and impact resistance of oxide layer formed during high temperature oxidation. Endo- and exo-thermic heats of Fe-2%Mn-0.7%C showed similar with Fe-0.77%C alloy. Endo- and exo-thermic temperatures deceased with increase in Mn concentration. Fe-Mn-C alloy did not show sufficient oxidation resistance at high temperature, whereas the aluminized sample showed a superior oxidation resistance due to the formation of continuous Al2O3 layer. Thinner Al2O3 layer is formed on the alloy sample by the aluminizing with lower Al concentration and shorter time and its latent heat become larger. The Al2O3 layer of the aluminized and oxidized samples were not peeled and significant weight change did not also occur after the experiment using the rotary kiln type furnace.