Viabilidade de queima de casca de eucalipto em fornos de cimento

Abstract

Cement factories, have rotary kilns that use fuels, either fossil, coprocessed or renewable (biomass) and are capable of absorbing all the ash produced during the process, as well as allowing the raw material to be adapted to new fuels. Currently, cement companies already coprocess tires, liquid or paste fuels and signal and increasing demand for biomasses. The objective was to study the of this research is to study the viability of burning eucalyptus bark in cement kilns. Approximately 10 tonnes of eucalyptus bark (waste from a panel industry) were used. Eucalyptus bark was characterized by immediate analysis (ash content – ASTM D1102-84, volatile content – ASTM E872-82 and fixed carbon by difference), bulk density (DIN 14778), moisture (ASTM E871-2013.30), PCS by calorimetric pump (IK C200), thermogravimetric analysis (TGA/Perkin Elmer), scanning electron microscopy (SEM/HITACHI TM 3000) coupled to X-Ray spectroscopy by energy dispersion (EDS). The results by immediate analysis showed an ash content of 4.89%, volatiles of 78,46% and a fixed carbon of 16.65. The SEM/EDS analyzes indicated aluminum and silica with more than 30% suggesting material contamination. The moisture varied between 20 to 45% and density from 33 to 52 kg/m3 indicating a very heterogeneous material. The PCS of the eucalyptus bark was 4206 kcal/kg, a value considered attractive for the cement industries. The TGA showed a final decomposition temperature of 600 º C favoring a rapid burning in cement kilns, where the control temperature is close to 880 º C. As a result, the burning of the eucalyptus bark became viable in the cement kiln at 2.5t / h, allowing for 7% thermal replacement, preserving quality and the environment. The results also indicate the possibility of increasing the dosage of the eucalyptus bark, requiring a longer period of tests to ensure the required limit for the quality of the clinker.