Date of Award
Doctor of Philosophy (PhD)
Michael D. Mann
To meet the metrics set forth by the Clean Power Plan, industry can use gasification or replacement of petroleum with biofuels. However, tars formed in gasification are difficult to remove, and biofuel-petroleum blends may have issues with fuel stability, corrosion, and miscibility.
Tar cracking was studied in both a laboratory-scale updraft gasifier, with a municipal solid waste feedstock, and tar cracking reactor system and in a bench-scale tar cracking reactor. The laboratory-scale system demonstrated that the optimal temperature was at least 800Â°C, that thermal cracking accounted for 85% of tar destruction, and that metal-based catalysts were the most promising. The bench-scale system, which used naphthalene as a model tar compound, demonstrated that a powder dolomite catalyst was most effective, that trona compared similarly to Plum Run dolomite, and that nahcolite was ineffective.
Hi-pour fuel oil, lo-pour fuel oil, crude jatropha oil, biocrude derived from animal renderings, biodiesel (refined biocrude), crude palm oil, and ultra-low sulfur diesel were blended at 75Â°F, 170Â°F, and 220Â°F. Flash points, pour points, and cloud points were determined for select oils and blends. 304 stainless steel, 316 stainless steel, brass, mild steel, and 410 stainless steel coupons were immersed in samples of each oil type and heated to 175Â°F to test for corrosive activity; these samples were examined every two weeks for fourteen weeks. Overall, blends containing biocrude and palm oil were
marginal to unacceptable due to the large proportion of waxes at ambient temperatures; all other fuel blends were acceptable for use in industry. Significant corrosion was observed on the brass in biocrude, brass in jatropha, brass in biodiesel, brass in palm, and brass in lo-pour fuel oil; the most significant corrosion was observed on the mild steel in biocrude. All samples had corrosion rates of < 1 mpy. Overall, the oils had the most effect on the brass samples.
Bjorgaard, Stacy Joan, "Characterization And Catalytic Cracking Of Tar Obtained In Coal / Biomass / Municipal Solid Waste Gasification: The Use Of Basic Mineral Catalysts And Miscibility, Properties, And Corrosivity Of Petroleum-Biofuel Oils And Blends For Application In Oil-Fired Power Stations" (2015). Theses and Dissertations. 1744.