Pyrolysis of domestic based feedstock at temperatures up to 300 °C

This article reports the state of the art of the characteristics of products derived from the pyrolysis of municipal solid waste. The by-products which arise at more elevated temperatures are discussed so that the outcomes of low temperature pyrolysis may be put into context. Our throwaway society is a globally growing issue, the continued discarding of valuable resources into landfill sites is highly undesirable due to many of these materials being non-biodegradable and some may produce toxic gases which are harmful to the environment if discarded in an uncontrolled way. Domestic and industrial sorting and transport of discarded resources result in an increase in carbon footprint as well as a high cost. Therefore, an alternative resource management method is required in order to achieve a more sustainable and less harmful method of managing these valuable resources in the future. Below 300 °C, the products of pyrolysis are generally expected largely to contain biochar, bio-oil and syngas. However, the phase distribution and chemical composition of the products is highly dependent on the feedstock used as well as the operating parameters of the process. Plant based feedstock produces more biochar while plastic based feedstock produces more bio-oil. The composition of products can be analysed using gas chromatography/mass spectrometry. Current applications of pyrolysis are focused on high temperatures due to the increased yields of gases and bio-oils, which are more valuable. Biochar, however, is becoming increasingly popular due to its various applications such as a filter material for water purification. Low temperature pyrolysis is an area where further research is required in order to produce economically viable processes.