Study on the pyrolysis and combustion characteristics of municipal solid waste in a fixed bed

Pyrolysis shows potential as a resource treatment technology for municipal solid waste (MSW). In this paper, pyrolysis and combustion characteristics of typical MSW in constant temperature were investigated by reacting in a fixed bed electric heating furnace. First, the pyrolysis gas compositions of typical waste fractions such as paper, fabrics, kitchen rubbish, branches, plastics and rubber were investigated as a function of time at 750 °C. The results show that for different MSW components, reaching the peak of pyrolysis gas content spends a different time. The H₂ content increases with the increase of pyrolysis time, which indicates that the dehydrogenation reaction is more intense at the high-temperature stage, and a certain amount of hydrogen is precipitated when the large molecules are decomposed into small molecules. However, as a polymer compound, the H₂ content of rubber increases at the beginning of pyrolysis, but with the increase of time, the H₂ content begins to fluctuate and there is no obvious pattern. Secondly, the MSW was combined into by these typical components according to a certain proportion, and then the relationship of flue gas with temperature and excess air coefficient was studied using this MSW as fuel. The results show that NOx content of flue gas with the increased temperature, the increase amplitude is bigger, while with the increase of excess air coefficient, the increased amplitude is smaller. The SO₂ content of flue gas has a positive correlation with temperature and a negative correlation with excess air coefficient. This indicates that the use of lower temperatures and higher excess air coefficients can help to reduce pollutant gas emissions.