Investigations into the fate and behavior of selected inorganic compounds during biomass gasification

Two sets of gasification experiments were performed in an effort to understand the fate of biomass nutrients and the effects of feedstock potassium on carbon conversion during gasification. The purpose of this research was to develop a comprehensive understanding of the issues of sustainability and efficiency facing biomass gasification. The results of these studies are described in detail within this thesis. The first study evaluated the fate of biomass nutrients in an integrated system of biomass production and gasification. Eight plots of switchgrass were grown and harvested for use in this study. Four plots were fertilized with 65 kg ha -1 of nitrogen (N) and four plots were not fertilized. Three essential biomass nutrients N, phosphorus (P), and potassium (K) as well as carbon (C) were individually tracked through a fluidized bed gasifier and subsequent gas clean up equipment. Mass balances were performed on each element to determine the percentage of that element that was able to be accounted for and the percentage that was able to be recovered in a form suitable for use as a soil amendment. The percentage of C recovered in a form suitable for field sequestration was independent of fertilizer N input and represented 13±1% (mean±SD) of switchgrass C. Recovery of N in a form suitable for soil amendment was 55±7% of switchgrass N and was also independent of fertilizer N. The percentages of P and K recovered in forms suitable for soil amendment were both higher for the fertilized treatment of switchgrass than the unfertilized treatment. Recovery of P in a form suitable for soil amendment was 73±21% for the unfertilized treatment and 104±24% for the fertilized treatment. Likewise for K, recovery percentages for unfertilized and fertilized treatments were 61±9% and 71±9% respectively.