Pyrolysis Kinetics of Coffee Residue and Tea Residue by Thermogravimetric Analysis
The pyrolysis of municipal wastes, namely coffee residue(CR) and tea residue(TR), were evaluated as potential feedstocks for energy production. Thechemical properties such as ash content, fixed carbon, volatile matter, moisture content and ultimate analysis were obtained, showing that CR and TR are not environmentally friendly sources of energy bearing trace amount of nitrogen matter due to the fact that the fuel-bound nitrogen will be partly converted to nitrogen oxide (NOx) during biomass combustion. The thermal degradation and the kinetic parameters (order of reaction, activation energy and pre-exponential factor)of CR and TR are studied by thermogravimetric data using by least-squares techniques. The heating rates used for the analyses were 5, 10 and 20 oC/min and the activation energy was depended on the heating rate vary from 67.4 to 68.2 KJ/mol for CR and 53.84 to 60.98 KJ/mol for TR. The activation energyof CR from this study is fairly close agreement with spent coffee grounds found in literature but the activation energy of TR which is based on this study alone due to a lack of results from other studies.
Keywords: unused wastes; biomass; coffee residue; tea residue; kinetic parameters