Thermogravimetric analysis of the thermal decomposition of MSW in N2, CO2 and CO2/N2 atmospheres

Abstract

The thermal decomposition of municipal solid waste (MSW) from Huizhou under N2, CO2 and CO2/N2 atmospheres was analyzed using a thermogravimetric instrument. The results revealed that the higher the heating rate, the more the residual mass and the higher the weight loss rates of the peaks. Under CO2 atmosphere, the volatile release from 160°C to 650°C, with a pronounced peak and a small shoulder in the DTG curve. The weight loss below 650°C changed with atmosphere indistinctively except in the 80%N2/20%CO2 atmosphere. Low CO2 concentration influenced the residual mass, while when CO2 concentration was over 60%, the residual mass almost remained the same (32.2%). Replacement of N2 by CO2 promoted the char gasification in high temperature range. In 100%N2 atmosphere, the peak above 650°C was only shaped by the degradation of minerals and the residues were char and ash. As the CO2 concentration increased, this peak shifted to a higher temperature range, and char gasification played the principal role. Above 650°C, the DTG curve showed two peaks in 80%N2/20%CO2 atmosphere obviously, whereas only an obvious peak in other atmospheres. The residues were almost ash in 100%CO2 atmosphere. The nth order reaction model of several independent fractions was applied to evaluate the kinetic parameters and it fitted the weight loss well.