The Catalytic Impact of MnO Additive on the Selected Municipal Solid Waste Combustion Behavior Determined by Thermogravimetric Analysis

Abstract

The thermogravimetric (TG) and kinetic analysis have been performed to evaluate the catalytic impact of MnO additive on selected municipal solid waste (SMSW) combustion behavior. Nineteen kinds of the SMSW have been collected, cleaned, dried, and grounded to the size of less than 1 mm and then mixed with the same mass ratio. The addition of an additive to the SMSW was completed by virtue of blending the10 mg SMSW with 0.5 mg the MnO powder and then was ground thoroughly in the mortar to obtain the homogeneous mixture of SMSW/5%MnO. Subsequently, the sample was brought into the crucible uniformly. The sample combustion in the chamber was carried out under non-isothermal conditions at the controlled heating program of 10 and 30 oC/min, a temperature range of 25-1000 oC, and an air atmosphere flowrate of 100 ml/min. The sample mass loss during temperature and time escalation was recorded by a computer automatically to be a TG curve. The 1st derivative of the TG curve to the temperature or time represented the rate of sample mass loss and denoted as the derivative thermogravimetric (DTG) curve. In accordance with both TG and DTG curves, then the characteristic temperature parameters were determined. The Coats-Redfern method has been adopted to evaluate kinetic parameters in this study. To understand the catalytic effect of the MnO, the blending SMSW/5%MnO results were compared with the pure SMSW ones. The results indicated that the MnO additive has promoted the initial temperature decomposition toward the lower value and provoked the increasing mass loss rate. Moreover, the presence of MnO also decreased the activation energy in the main combustion region. The overall results revealed that the MnO additive has significantly impacted the dynamic of thermal decomposition during the combustion processes.