1. Introduction
Presently, biomass fuels are an increasingly
attractive primary energy source because of their
intrinsically renewable nature and potentially limited
generation of pollutants. Biomass usually
contains negligible sulfur and low concentrations
of nitrogen and heavy metals and is neutral with
respect to greenhouse gases. However, there are
issues in utilizing biomass as fuels, including the
low calorific value per unit volume and special
treatment required before utilization for economical
transport and storage. Moreover, controlling
the burning rate in the combustion equipment is
difficult since raw biomass fuel may be inhomogeneous
and have a remarkable burning rate. To
overcome these disadvantages, a newly developed
biomass-type fuel has been proposed, “Bio-coke
(BIC)” [1–4]. BIC, highly densified biomass