Hydrothermal deoxy-liquefaction of biomass model compounds with formate salt as hydrogen donor.
Sai Teja Neeli and Hema Ramsurn
Russell School of Chemical Engineering, University of Tulsa, Tulsa, OK 74104
Biomass consists of three biopolymers: cellulose, hemicellulose and lignin, all intertwined in a complex structure. In order to depolymerize biomass, these three components have to be degraded. However, because they are structurally and chemically different, these components degrade at very different temperatures and conditions. Therefore, this project aims to investigate the effect of hydrothermally deoxy-liquefying biomass model compounds (cellulose, hemicellulose and lignin) separately using a hydrogen donor. Sub- and supercritical water is used as solvent to liquefy the biomass model compounds. Calcium formate is used as the hydrogen donor because it is an inexpensive and non-corrosive compound. According to thermogravimetric analysis (TGA), calcium formate decomposes in the range of 350-450 °C and therefore the hydrothermal liquefaction experiments are carried out within this range. Preliminary results using switchgrass have demonstrated that the heating value of the biocrude is enhanced by 16% with the addition of calcium formate and there is a corresponding increase in benzene compounds. In this work, we probe the mechanisms that lead to the chemical changes observed to understand the contributions of the individual components of biomass and their interactions with each other. The identification of the compounds in the biocrude obtained from each model compound will help in formulating deoxy-liquefaction mechanism(s).