Biomass is receiving significant attention as a renewable energy resource for fuels and chemicals. The technology for conversion of biomass to ‘bio-oils’ via pyrolysis is a promising approach that has reached an intermediate stage of development. The underlying challenges in pyrolysis chemistry are the complex cellular structure of woody biomass and the presence of inorganic species within biomass that act as natural catalysts, significantly affecting the yield of bio-oil as well as its product distribution [1,2,3]. Understanding the molecular-level role of these natural catalysts is important to the development of biomass reactors. This research work aims to investigate the effect of calcium and magnesium on primary and secondary pyrolysis of cellulose. We considered both the homogeneous catalytic role of reactive metal ions (Ca2+, Mg2+) and the heterogeneous catalytic role of solid oxide particles (CaO, MgO) in the condensed cellulose phase. Various concentrations of metal ions are doped into pure cellulose from their inorganic salts (Ca(NO3)2 and Mg(NO3)2) using ion-exchange, while the corresponding oxides (CaO and MgO) are incorporated with cellulose by dry-mixing. Additionally, levoglucosan (LGA) was impregnated with inorganic salts through incipient wetness impregnation to study how the major product (LGA) breaks down to form secondary products. Determining the role of natural inorganic catalysts in altering pyrolysis chemistry within the intermediated liquid will allow for optimization of transport-kinetic models used to scale up and optimize pyrolysis reactors and contribute to the development of biofuel production processes.
(1) Y. Sekiguchi, F. Shafizadeh, “The effect of inorganic additives on the formation, composition, and combustion of cellulosic char,” Journal of Applied Polymer Science 29 (1984) 1267-1286.
(2) K. Raveendran, A. Ganesh, K.C. Khilart, “Influence of mineral matter on biomass pyrolysis characteristics,” Fuel 74 (1995) 1812-1822.
(3) P.R. Patwardhan, J.A. Satrio, R.C. Brown, B.H. Shanks, “Influence of inorganic salts on the primary pyrolysis products of cellulose,” Bioresource Technology 101 (2010) 4646-4655.