Experimental evaluation of waste tires utilization in cement kilns

The present work outlines the main results of a full-scale study conducted on the utilization of waste tires as auxiliary fuel in cement production. E xperimental tests were conducted for determining the influence of shredded tires on combustion conditions, emissions produced, and the characteristics of clinker obtained, for feeding ratios over 35% in terms of total heat in put. The addition of tire chips did not lead to any appreciable modificatio n in either the whole process or the quality of clinker produced; gaseous e missions were mostly unaffected, with significant improvements related to t he reductions obtained in nitrogen and sulfur oxides concentrations. Experi mental findings from tests conducted with tire chips exposed to kiln combus tion flue gases compare favorably with the typical burnout times derived fr om theoretical approaches. These experimental data and calculations to esti mate particle trajectories beyond the injection point, through proper theor etical analysis of the kinetic behavior, result in important indications fo r the shredding operation and for optimum injection modes.