Thermochemical processing of solid waste at high temperature and high pressure to produce high-value products and energy

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Canadians are among the greatest producers of municipal solid waste (MSW) in the World with 777 kg of MSW per capita disposed in 2008 (Statistics Canada [2008]). Only 25% of these MSW are recycled and approximately 3% are converted to heat and electricity in incinerators. Landfills are still used as the primary means for waste disposal, which represents an environmental concern due to leachate and landfill gas emissions, which only 80% can be captured in best cases. Non-residential waste production is also a concern as it accounted for two-thirds of total waste production in Canada. Furthermore, waste management is a global concern considering that the World’s MSW production rate is expected to grow from 1.3 billion tons/year in 2012 to 2.2 billion tonnes/year in 2025 and to 4.2 billion tons/year in 2050 (World Bank report [2012]). In a context of depleting reserves of conventional and easily processable resources as well as increasing stringent environmental regulations, Canadians would greatly benefit from a better utilization and valorization of waste. It would improve Canada’s environmental performance, offer new revenue streams for its industries and make its industries more competitive. To utilize and valorize waste, recycling is not always technically and economically possible due to cross-contamination and limitations of waste separation processes. Waste-to-energy (WTE) and waste-to-chemicals processes are promising avenues for waste utilization and valorization. Currently, incineration is the most widely used WTE technology, but it has a limited potential for waste valorization considering that it only generates heat and electricity, it has a low efficiency (13-24 %) and it produces pollutant emissions (SOx, NOx, UHCs, VOCs, dioxins, furans and PM). Pyrolysis and gasification are promising technologies to increase WTE process efficiencies and convert waste into high-value chemicals. Current research on waste gasification and pyrolysis is mostly performed at ambient pressure and temperatures in the range of 400°C-1000°C. Operating these processes at high pressure and high temperature (HP-HT) may offer some significant advantages: (1) reduction of the fixed capital costs due to the elimination of downstream equipment (compressors), (2) reduced reactor and piping dimensions due to increased reaction rates, (3) increased process efficiency, etc. However, there is a lack of experimental research at high pressure and high temperature (HP-HT) and it remains a relatively unexplored area of research. The present proposal is intended to generate novel knowledge on the pyrolysis, gasification, and combustion experiments of solid waste materials at high temperatures (400°C-1600°C) and high pressures (1-30 atm) (HT-HP).