An investigation on the pyrolysis of municipal solid waste

Rising energy consumption in countries such as India has led to increase interest in the conversion of solid waste into usable products such as fuels. Of the various processes that can be used to convert solid waste into fuels the pyrolysis process has been identified as having significant potential. In this study the pyrolysis (conversion) of three components of municipal solid waste: kitchen base vegetable waste, plastic waste and activated sludge was investigated. The thermal decomposition of the waste’s studied were evaluated over a temperature range of 673 – 1073 K and retention time varying from 60 – 180 min. The quantity of solid, liquid and gaseous products generated from pyrolysis experiments were determined in all tests. The gaseous products were analysed from hydrogen, methane, ethane, propane and carbon-di-oxide. Liquid products obtained were analysed using Gas Chromatography-Mass Spectroscopy for selected tests. The solid products obtained from selected test were analysed using Scanning Electron Microscopy and BET surface area analyser. Pyrolysis experiments were also performed in the presence of additives (silica gel/sand), these additives were mixed with the dry waste samples in the ration of 1 (silica gel/sand):9 (dry waste) prior to being subjected to pyrolysis. Also to understand the potential of the wastes studied as renewable sources of energy, a comprehensive energy analysis (based on net energy gain or loss) over the pyrolysis process was carried out. Pyrolysis studies conducted using various components of municipal solid waste showed that temperature and retention time had a significant influence on the amount and composition of the products generated. Increasing both temperature and residence time led to an increased amount of gaseous products. Research was also conducted on utilizing the char (one of the products generated from pyrolysis of kitchen based vegetable waste) as an adsorbent for the removal of dye compounds from aqueous solution. The char was converted to activated carbon through acid-base treatment prior to its application as an absorbent. <br><br>