Compositional and Thermal Evaluation of Lignocellulosic and Poultry Litter Chars via High and Low Temperature Pyrolysis

• Published in: Bioenergy research 2013-03, Vol.6 (1), p.114
• Main Authors: Novak, J. M, Cantrell, K. B, Watts, D. W
• Format: Article
• Language: English
• Subjects: Agricultural biotechnology; Agricultural production; Agricultural wastes; Bagasse; Biodiesel fuels; Biofuels; Biomass; Biomass energy; Cellulose; Force and energy; Gases; High temperature; Lignocellulose; Litter; Low temperature; NMR; Nuclear magnetic resonance; Poultry; Poultry industry; Pyrolysis; Raw materials; Studies; Sugarcane; Temperature; Thermal energy; Thermal properties; Trace elements
• ISSN: 1939-1234; 1939-1242
• DOI: 10.1007/s12155-012-9228-9

Inorganic elements in biomass feedstocks can influence thermochemical reactions as well as the resultant char's elemental, compositional, and thermal characteristics. Chars were produced using slow pyrolysis under low ([less than or equal to]400°C) and high ([greater than or equal to]500°C) temperature regimes from sugarcane bagasse, peanut hulls, pecan shell, pine chips, poultry litter, and switchgrass. The chars and raw feedstocks were characterized for their elemental, structural, and thermal properties to ascertain the implications of feedstock selection and pyrolysis temperatures on these properties. Char mass yields from the six feedstocks ranged between 28% and 78% by weight while carbon yields ranged between 44% and 89%. In both instances, lower yields were obtained with increasing pyrolysis temperature. Higher pyrolysis temperatures ([greater than or equal to]500°C) resulted in more neutral to alkaline chars possessing greater ash contents and increased aromatic character with narrow O/C and H/C ratios. A significant exponential curve response (r.sup.2 = 0.87, P 30 MJ kg.sup.-1. The chars' HHV values inversely correlated to their total ash and Cl content. Lignocelluloses chars had better thermal characteristics and lower ash quality concerns implying suitable service in thermal energy production. In contrast, poultry litter char had greater ash contents, medium HHV values, and contained corrosive inorganic elements, which rendered it problematic as a feedstock for thermal energy generation.