Removal Effect of Ash and Metallic Species by Washing from Empty Fruit Bunch Byproducts in Palm Mills on Pyrolytic Characteristics to Produce Bio-Crude Oil

The fast pyrolysis of biomass, empty fruit bunches from the palm mill industries, was conducted in a lab-scale bubbling fluidized bed reactor with a throughput of 1 kg/hr at temperatures ranging from 400 to 650 °C. For producing a higher yield of bio-crude oil with better homogeneity, washing methods were applied to the empty fruit bunch with water and nitric acid to remove ash and alkali and alkaline earth metallic species. After washing, the ash content decreased from 5.9 to 1.53 wt%, and over 80 wt% of alkali and alkaline earth metals, such as potassium, magnesium, calcium, and sodium, was removed. For considering economic feasibility and efficiency, the biomass treated with tap water for 1 day could be enough to produce oil with the highest yield of 48 wt% at 500 °C. The homogeneity of bio-crude oil produced by fast pyrolysis from the empty fruit bunches with nitric acid washing increased to 98%. The results of chemical compounds in oil could also confirm such quality improvement by less number and higher fraction of phenol compounds.