Characteristics of palm bark pyrolysis experiment oriented by central composite rotatable design

The rotatable design was applied for directing pyrolysis experiment of palm bark with the variation of retention time and reaction temperature. Based on the regression equations, the optimal operating conditions were extrapolated at 13.2 min, 459 °C and 15.7 min, 475 °C. The gas product comprised mainly C1–C4 hydrocarbons with the content up to 58.2 wt% while the liquid product was a complex mixture composed of mostly oxygenated compounds. Owing to using the high pressure condition as in tubing reactor, the reaction characteristics were different from those at normal pressure, thus possibly resulting in the high selectivity for liquid product. The analysis result of solid residue after reaction showed that the oxygen content was decreased noticeably to 25.4 wt% as compared to that of raw biomass due to pyrolysis.