The aim of the Japanese cabinet council's 'Biomass Nippon Strategy' is to increase the utilization of biomass as one of the ways to reduce the dependence on fossil resources. However, there are various problems associated with the use biomass, one of which is the cost associated with the collection and transportation of biomass. Biomass has high moisture content and low bulk density. The biomass solidification technology developed by Ida et al. partly aims to solve the transportability problem. This study shows physical properties of high density and hardness of the new briquette produced from herby biomass. The relationship between apparent density and maximum compressive strength and an effect on the maximum compressive strength by black colorization are considered. Also, an attempt is made to explain the effect on properties of the briquette by hemi-cellulose and lignin in the region before semi-carbonized region. As a result, the relation between the apparent density and the compressive strength shows that maximum value exists as characteristics of the herby briquette. The maximum apparent density for all processing conditions is 1.38 g/cm3 at the initial moisture 0.10 kg/kg-wet - processing temperature 473 K. The maximum compressive strength for all processing conditions is 127 MPa at the initial moisture 0.05 kg/kg-wet - processing temperature 453 K. Furthermore, the effect of black colorization indicates that when the area of black colorization is increased for the surface of herby biomass briquette by increased in the processing temperature, the maximum compressive strength is decreased due to reduction in the adhesion of lignin. Consequently, high-density and high-hardness of the new briquette can be controlled by the initial moisture and the processing temperature.
