Untitled in english

Author(s)

Jefferson Caponero

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Escola Politécnica (EP/BC)
• Defense date: 2002-12-11

Examining board members

Jorge Alberto Soares Tenório; Jose Deodoro Trani Capocchi; João Andrade de Carvalho Junior; Francisco Rolando Valenzuela Diaz; Carlos Alberto Mariotoni

• Advisor: Jorge Alberto Soares Tenório

Abstract

The tire is an expressive component of Municipal Solid Waste, manly when its occupied volume is considered. Its treatment by pyrolysis and/or by combustion stands for a list of advantages, such as: landfill releasing and a production of a high quality fuel. The exploitation of new natural resources is becoming more difficult each day, basically due to the environmental damages caused by this type of activity. This work presents a study on the thermal behavior of waste tires using thermal analysis, in order to optimize the combustion process of tires, having the goal of generate energy. Samples were investigated at atmospheres of nitrogen, argon, oxygen and mixtures of these gases at temperatures up to 1000°C, under heating rates between 1 to 50°C/min. Results showed that the behavior of each sample is related to both the atmosphere composition and the heating rate. Also, a laboratory investigation on the emissions from batch combustion of waste tire chips in fixed beds, to identify techniques and conditions that minimize toxic emissions, was performed. Tire derived fuel (TDF), in the form of waste tire chips, was burned in a two-stage combustor. Batches of tire chips were introduced to the primary furnace where gasification and oxidative pyrolysis took place. The gaseous effluent of this furnace was mixed with streams of additional air and, subsequently, it was channeled into a secondary furnace (afterburner) where further oxidation took place. In someruns, the gaseous effluent of the first furnace was filtered using a silicon carbide (SiC) honeycomb wall-flow filter working at the furnace temperature and than channeled into a secondary furnace (afterburner). The hot filtering section in between the two furnaces allows the retention and further oxidation of most of the particulate generate. In other runs, the atmosphere of the first furnace was changed in order to obtain a pyrolysis process followed by the combustion of the volatile matter. This change has shown similar results than the introduction of the ceramic filter. The arrangement of two furnaces in series allows for independent temperature control; varying the temperature in the primary furnace influences the type and the flux of pyrolyzates. The additional-air mixing section in between the two furnaces allows for mostly heterogeneous and fuel-lean combustion in the afterburner. Results showed that the operating temperature of the primary furnace, in the range of 500-1000°C, the existence of the afterburner, the presence of the ceramic filter and the composition of the furnace atmosphere had a marked influence on the emissions of pollutants. (AU)