Black Liquor Gasification Entrained Flow Gasifier Kristin Hecht

Black Liquor Gasification: Entrained Flow Gasifier Kristin Hecht, Undergraduate Student, Chemical Engineering, BYU Skigh Lewis, Undergraduate Student, Chemical Engineering, BYU Research Group Advisors: Prof. Larry Baxter, Chemical Engineering, BYU, Prof. Dale Tree, Mechanical Engineering, BYU Objectives: • Determine properties of black liquor and smelt under gasification conditions • Model high-temperature, entrained flow black liquor gasifiers • Understand suggest optimization strategies for liquor injectors in entrained flow gasifiers Thermal Conductivity Density 65 ºC Adapted from Adams Adapted from Zaman Adapted from Adams 38 ºC Black liquor density decreases linearly with temperature and increases linearly with solids content within thermodynamic phases. Thermodynamic transitions occur at 65% and 80% solids. A second order model is used to predict liquor density. Liquor Injectors Viscosity Mechanism for Sheet Breakup: Solids Content, % Adapted from Chemical Pulping Black liquor viscosity is strongly dependent on composition. For liquors above 50% solids, a second order power series describes viscosity well. Sponsored by DOE Office of Energy Efficiency and Renewable Energy • Waves grow in the sheet and localized thin spots occur • • Spots rupture due to air pockets or nonwettable particles Holes grow into perforations due to surface tension forces Holes combine and sheet become a network of strands Strands become unstable and break into droplets Density, viscosity, and thermal conductivity are strongly dependent on the solids concentration in the liquor and decrease with temperature. Good correlations for density and viscosity have been developed. These correlations are specific to certain liquors as well as pulping and cooking conditions. Smelt properties lend themselves less well to such predictions. References: Chemical Pulping. Johan Gullichsen and Carl-Johan Fogelholm, ed. Papermaking Science and Technology, Book 6 B. Adams, Terry, et. Al. Kraft Recovery Boilers. Zaman, Abbas A. , J. S. Deery, T. W. Mc. Nally & Arthur L. Fricke (1997). “Effects of Pulping Variables on Density of Slash Pine Kraft Black Liquors: Predictive Models. ” TAPPI Journal 80(9) 199 -207.