Thermal Conversion and Catalysis Implementation for Food Waste Valorization
Open Access
- Author:
- Capece, Sofia
- Area of Honors:
- Chemical Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Phillip E Savage, Thesis Supervisor
Themis Matsoukas, Thesis Honors Advisor - Keywords:
- Hydrothermal Liquefaction
Food Waste
Biofuels
Catalysts - Abstract:
- With tons of food waste ending up in landfills every year, it would be advantageous to determine a way to relegate some of this into a useful energy source such as a liquid fuel. Several sets of experiments are included in this study including catalyzed hydrothermal liquefaction (HTL) of simulated food waste, food waste biochar upgrading by either HTL or pyrolysis, and the HTL of combinations of food waste and polystyrene. The effects of different catalysts, including supported metals, metal oxides, and additives, on the HTL of simulated food waste (350°C, 40 minutes holding time, 10 wt.% reactor loading, and 50 wt.% catalyst loading with respect to the dry food weight loading) on biocrude oil yields and energy recoveries were measured. The highest biocrude oil yield achieved in this study was 49 wt.%, with metal oxide SiO2. La2O3 and CeO2 were also effective catalysts with oil yields of 45 and 43 wt.%, respectively. Energy recoveries for these aforementioned metal oxides along with Al2O3, were 83% and higher. The noncatalyzed HTL of food waste gave 67% energy recovery. Food waste biochar, either produced by hydrothermal carbonization (HTC) or pyrolysis was upgraded by HTL or pyrolysis to yield a liquid biocrude oil. While HTL on pyrolytic biochar gave the highest overall biocrude yields, the HTC biochar upgraded by HTL led to a biocrude oil with overall higher percent areas of fatty acids and hydrocarbons (as determined by GC-MS). Both fatty acids and hydrocarbons are desirable products for high-quality liquid fuels, but further analysis into the energy recovery of these products is required to assess their benefits. The HTL of simulated food waste and polystyrene (PS) in different ratios was performed at either 300 or 350°C for 30 minutes at 5 wt.% reactor loading. Synergistic interactions, which cause the experimental biocrude oil yield to be higher than the calculated yields from the biocrude yields from food waste and PS alone, were potentially seen at 25 wt.% PS/ 75 wt.% food waste at 350°C. Further experiments are required to assess the quality of the biocrude oil, and the contributions of the dissolution of PS in one of the extraction solvents, dichloromethane.