TGA pyrolysis and gasification of combustible municipal solid waste

• Pyrolysis and gasification behaviors of 8 MSW are investigated and compared.
• The discrete DAEM is applied to analyze the kinetics of pyrolysis and gasification.
• At CO2 atmosphere, the Boudouard reaction between CO2 and char happens above 700 °C.
• The activation energy of Boudouard reaction of CO2 and carbon is around 327 kJ/mol.

It brings modeling, design and operation of thermochemical treatment systems a huge challenge for a large variety in municipal solid waste (MSW) composition and differences in thermal behavior of MSW components. The pyrolysis and gasification characteristics of 8 different combustible solid wastes, representing the most common components of MSW, were investigated using a thermogravimetric analyzer (TGA). Their decomposed characteristics in different atmospheres (N2 and CO2) was analyzed and compared, which identified as pyrolysis and gasification, respectively. The results showed that pyrolysis characteristics of 8 materials were similar to their gasification with the temperature less than 600 °C. The pyrolysis degradation of eight materials was slight above 600 °C, while the gasification degradation in the range of 700–900 °C was obvious because of the reaction between CO2 and char. The discrete distributed activation energy method (DAEM) was applied to analyze kinetics of pyrolysis and gasification. When pre-exponential factor was given as 2.2 × 1013(s−1), the activation energy of cellulose decomposed reaction was approximately 176 kJ/mol, while the activation energy of the reaction between CO2 and char was 327 kJ/mol.