Densifi cation of agricultural residues may be used as fuel for the
generation of energy. Some of the methods available for compaction of
the residues are the piston press, screw press, roller press and palletizing
machines. Many researchers have tried the densifi cation mechanism
of different biomasses. It involves application of attractive forces
between solid particles, interfacial forces, capillary pressure, adhesive
and cohesive forces, mechanical interlocking behavior and formation
of solid bridges. Strength of the compactness depends upon material
characteristics and process variables like pressure, temperature and use
of binding materials. This article reviews the different biomass densifi cation
methods and its mechanism. A comparative study has been made
for different methods.