The Utilization of Douglas-Fir Bark for the Production of Oxalic Acid and High Density Carbon Pellets

The production of oxalic acid by the catalytic oxidation of Douglas-fir (Psedotsuga menfiesii (Mirb) Franco) bark and subsequent pyrolysis of the residue to produce high density carbon pellets is discussed. Kinetic rate data are presented for oxalic acid production from Douglasfir bark. A maximum yield of 38 wt% oxalic acid has been obtained in 8 h at 80°C with 62.5 vol% HNO₃ and 0.5 mg V₂O₅/g of bark. Additional oxalic acid can be produced by the conversion of pyrolytic oils and tars (obtained during carbonization of the residue) to increase the total yield to 45 wt%. An economic analysis based on the current cost of oxalic acid indicates the viability of the proposed process.