Date of Award
Master of Science
Theodore J. Heindel
The danger of climate change looms in the minds of researchers across the world. To combat this threat, many have focused efforts on the development of clean energy. In this study, the renewable resource that is investigated is biomass, specifically red oak. Energy can be extracted from biomass by fast pyrolysis, where the feedstock is rapidly heated within a reactor to approximately 500℃ in the absence of oxygen. This produces biochar, ash, and condensable gases that, once cooled, become a bio-oil. To optimize economic feasibility, the process must operate continuously. This presents a problem—the presence of ash as a fast pyrolysis product has been experimentally shown to decrease reaction yield over time. Therefore, the ash must be separated and removed, regenerating the associated heat carrier. For this study, this is accomplished by applying the concept of particle elutriation. Solid products from fast pyrolysis are loaded into a fluidized bed reactor, and ash elutriation is studied for temperatures ranging from 450℃ to 750℃ with varying sweep gas velocities. Elutriated solid particles are captured with a collection cyclone that is designed using the Barth model. Captured particles are quantified using Thermogravimetric Analysis (TGA) and Inductively Coupled Plasma (ICP) analysis, allowing one to determine mass composition and elemental concentrations. Results show that, in general, increasing sweep gas velocity improves the elutriation efficiency of ash particles. However, char elutriation was significant in all tested conditions, and likely impacted the ash collection efficiency of the cyclone. Results from ICP indicate that calcium and potassium are the most abundant metals in cyclone catch samples, and have much lower concentrations in sieved samples from the reactor bed following regeneration.
Erickson, Dane, "An examination of ash elutriation from a fluidized bed regenerator" (2018). Graduate Theses and Dissertations. 16349.