Master of Engineering Science
Chemical and Biochemical Engineering
The objective of this thesis is to investigate the effects of applied bed mixing and vapor phase residence time on the thermal cracking of agglomerating and non-agglomerating feedstock. Bitumen thermal cracking was investigated using a novel Mechanically Fluidized Reactor system and a pilot-scale Fluid Coking Reactor. Bed mixing and vapor residence time were studied to determine their impacts on agglomerate distributions, yields, and the quality of liquid product. Birchwood pyrolysis was investigated using a fluidized bed reactor to determine the impacts of particle-bed mixing on the pyrolysis of a non-agglomerating feedstock, to provide contrast to the agglomerating bitumen-coke system. It was observed that applied bed mixing destroyed agglomerates and dispersed the trapped reacting feedstock among smaller fragments, leading to reductions in coke yield and increased liquid production. Applied bed mixing resulted in lower viscosity, lower-molecular weight liquid product at short vapor phase residence times. Prolonged vapor phase residence times facilitated the cracking of vapors into non-condensable gas, while increasing the concentration of more refractory, higher-viscosity, higher-molecular weight components in the liquid product. In addition, it was determined that the use of a feeding system which disperses non-agglomerating biomass upon injection, in conjunction with a fluidized bed pyrolyzer, is an effective system and enhancing particle-feedstock mixing further provides no additional benefits for pyrolysis.
Stanlick, Clayton, "Effects of Mixing and Vapor Residence Time on the Thermal Cracking Performance of Fluidized Beds" (2014). Electronic Thesis and Dissertation Repository. 2435.