Rapid Carbonization Process Using Heat Storage Materials and Characterization of the Obtained Char

Abstract

Carbonization behavior of biomass in the rapid carbonization/pulverized process using heat storage materials was experimentally examined. Biomass samples were charged into a rotary kiln-type electric furnace with stainless balls. Obtained biomass chars were evaluated by means of gasification test in CO₂ atmosphere using a thermal gravimetry. The char was classified into two type, “fine” and “coarse”, by particle size.

“Coarse” char contracted with increasing holding temperature. Crashing of biomass char was observed at the holding temperatures over 600°C and fine char was formed. Melted structure was observed on the surface of “coarse” char indicating rapid heating. Yields of the total char are decreased with increasing holding temperature due to vaporization of volatile matters like tar. On the other hand, the yield of “fine” char is increased with increasing rotation speed when carbonization reaction sufficiently proceeded.

The char obtained by the present carbonization experiment at between 600 and 800°C for 10 min showed similar gasification property with CO₂ to that prepared by normal carbonization at 800°C for 1 h.

Concept of waste heat recovery and rapid carbonization process of biomass applying heat storage media.