Effects of temperature and heating rate on the characteristics of molded Bio-Char

Abstract

A slow pyrolysis of pinewood was investigated in this paper. Through the briquette process, the pinewood sawdust becomes molded biomass. The molded Bio-Char was produced from molded biomass with different pyrolysis factors, and the Bio-Char's heating value, char yield rates, and physicochemical and morphological properties were investigated. Molded Bio-Char's characteristics depended principally on pyrolysis factors. At low temperature (400 °C), the char yield rate was positively correlated to the heating rate. But at higher temperatures (500 to 700 °C), the char yield rates decreased as heating rates increased. As pyrolysis temperature increased from 400 to 700 °C, the following increased in molded Bio-Char: Fixed-Carbon content, percentage carbon, heating value, ash content, as well as surface areas. And its pore structure, graphite degree, and polymerization degree achieved a higher level. Compared with pulverized Bio-Char, the molded Bio-Char had a higher char yield rate, ash content, graphite degree, and structure ordering. The molded Bio-Char obtained from a low temperature (400 °C) and high heating rate (15 °C/min) can be used as a reducing agent, the molded Bio-Char from 600 °C is recommend as an activated carbon precursor, and the molded Bio-Chars from low temperature (400 °C) have a higher efficiency as fuel.