SECONDARY SOLID FUEL (CSS) WITH HIGH CALORIFIC VALUE FROM UNSEPARATED MUNICIPAL WASTE

The patented "Attritor Mill" system is constituted of a particular mill where the grinding is done by accelerated steel balls that hat grind the material by the impact force and friction. The micronization of the municipal wastes is carried out by a magnetic separation of ferrous materials, then the separation with eddy current for non-ferrous metals. The waste is loaded into a shredding system where is reduced in size to about 4-6 cm, and then in a crushing roller system and on a vibrating screen to eliminate cementitious fragments, glass and ceramic. The waste is micronized at extremely high speed and which allows the grinding action by shocks and frictions. The resulting product is constituted of very small size flakes with dimension of about 500 microns. The resulting product is extremely poor in metals, salts and halogens. The determination of calorific value, chlorine, mercury and other heavy metals was carried out at the CNR-IPCB institute whereas gasification experiments were carried out at the University "la Sapienza" department of mechanical and aerospace engineering. The classification of CSS has been carried out over a period of 12 months with an annual production of about 120 tons. A calorific value of 17 MJ/Kg has been obtained with chlorine, mercury and heavy metals content within the limits provided by the CSS classification, NCV3; Cl 2; Hg 1. The gasification of CSS produced a Syngas with the following composition: H2 (50%), CO(14%), CO2(24%), CH4(10%).