Pretreatment of waste activated sludge (WAS) and the subsequent near-critical water gasification (NCWG) is a potential avenue to convert WAS into value added products. Part one of the research investigated thermal and thermochemical pretreatments. No difference was observed in the percentage of sludge liquefied beyond 10min between 200°C to 300°C. It was found that pretreated activated sludge supernatant (PASS) doubled the gas yield compared to untreated sludge when gasified. The order of effectiveness for sludge treatment was thermo-alkali > thermal > thermo-acid for hydrogen production in NCWG. Part two investigated NCWG parameters to identify optimal conditions. High gasification yields were obtained using a commercial catalyst (Raney nickel), with hydrogen content of 65-75% of the gas phase products. Thermo-alkali treated PASS was found to perform well at subcritical temperatures with 25% higher yields than thermally treated PASS. Increased catalyst loading had little additional effect on gas yields above 0.075g.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/31641 |
| Date | 04 January 2012 |
| Creators | Wood, Cody D. |
| Contributors | Farnood, Ramin |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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