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Pelletization and Thermo-Catalytic Reforming of Municipal Solid Waste
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- Author / Creator
- Martinez Castellanos, Benjamin M
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Meeting the objectives of the Paris Agreement requires society to reduce greenhouse gas (GHG) emissions levels in every sector. Waste management has a key role in achieving these objectives and is fundamental for sustainable growth. Some municipal solid waste (MSW) streams have the potential for waste-to-energy conversion, thereby increasing the waste diversion rate. Thermo-catalytic reforming (TCR) is a conversion method based on pyrolysis that allows the conversion of an organic feedstock into valuable products like bio-oil, biochar, and syngas. TCR requires a homogeneous feedstock that can be produced through pelletization. There is very little information available on utilization of different components of MSW streams for production of liquid fuel production using TCR. This research work is an effort to address this gap.
The first part of this study focuses on the size reduction and pelletization of fractions of the municipal solid waste, that is, digestate, source-separated organics (SSO), and refuse-derived fuel (RDF). The effect of particle size and moisture content in the grinding and pelletization was assessed at a laboratory scale. While the digestate could not be pelletized, SSO and RDF pellets were successfully produced. The highest pellet durability values were 98.2 % for RDF and 97.4 % for SSO. The specific energy consumption for grinding and pelletization was as low as 2281.15 KJ/kg for RDF and 489.49 KJ/kg for SSO. The RDF pellets showed a high heating value (HHV) of 21.5 MJ/kg and an ash content of 9.8 %. Seasonal variation was observed in the SSO pellets, with a lower HHV (13.9 MJ/kg) and higher ash content (34.7 %) during the spring/summer seasons and a higher HHV (19.5 MJ/kg) and lower ash content (13.51 %) during the winter season.
In the second part of this study, a 2 kg/h lab scale TCR unit was used to investigate the thermo-catalytic reforming of SSO pellets. Two pyrolysis reactor temperatures (400 °C and 500 °C) and three post-reformer temperatures (500 °C, 600 °C, and 650 °C) were used to study the effects of process temperature on product yields and characteristics. At higher process temperatures of 500 °C in the reactor and 650 °C in the reformer, the highest energy conversion efficiency of 92.37 % was achieved. These conditions also yielded a higher syngas production of 42.79 % with an HHV of 19.13 MJ/kg. Higher temperatures resulted in lower bio-oil yields of 2.11 % but improved quality, that is, the viscosity, oxygen content, and total acid number were reduced. Lower process temperatures resulted in a maximum bio-oil yield of 6.20 % with an HHV of 37.2 MJ/kg. The effect of temperature on bio-oil characteristics was also examined. Biochar had an HHV of 9.25 to 10.24 MJ/kg and a yield between 41.17 % and 46.25 %. The information developed in this research can help in understanding the potential pathways of utilization of MSW for liquid and gaseous fuel production. -
- Graduation date
- Fall 2023
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.