Development of the compaction machine for the production of new shapes of pressed biofuels

Abstract

Briquettes and especially pellets became the fuel of the 21st century. These are pressed biofuels made from the biomass which have the required heat, shape, size, density and mechanical properties. Today, these pressed biofuels are made in the form of a block, cylinder, n-angle octagonal, either without or with the holes. Several analyses confirm that neither a block, nor the cylinder is the optimal shape for the production of pressed biofuels, both in terms of the production, storage, automated transport in the combustion process and the optimum combustion process. For this reason, we began to analyse different shape, size, density and mechanical properties of briquettes and pellets. In the first part of this article, the biofuel is described from these points of view. The result of this analysis is the new optimized spheroid shape of the pressed biofuels. The goal of the second part of the article is the construction design of a new compacting machine for manufacturing of the optimized shape of the compacted piece. The task is demanding due to the fact that in comparison to the production of cylindrical or square-shaped compacted pieces, the manufacturing of ‘quasi-spherical’ compacted pieces is discontinuous. Furthermore, unlike the standard types of compaction presses which compact the material between the two cylinders, it is necessary to hold the compacted piece for certain time under high pressure and at the high temperature. In this way, the lignin contained in compacted raw material becomes plastic and no further binding material needs to be added. The kinematics of a new compactor was therefore divided into two stages- ‘the stage of compacting’ and ‘the stage of load bearing capacity. This article describes an innovative and patent protected principle of compactor construction. The prototype of a designed machine has already been produced in our department. The first test results of this machine production as described in the conclusion of the paper confirm that kinematics and compactor construction were both correct.