Influence of Chemical and Thermal Pre-Treatment on Pyrolysis Product Constituents of Palm Empty Fruit Bunches

Bio-oil derived from palm empty fruit bunches (PEFB) mainly consists of oxygenated compounds, which has led to poor quality bio-oil with low energy content.In order to enhance the quality of the bio-oil, PEFB need to undergo a pre-treatment process to eliminate high oxygen content and moisture content from this biomass.In this study, the effect of individual and sequential pre-treatments of demineralization and torrefaction on palm empty fruit bunch (PEFB) samples was investigated and the pyrolysis product yields of untreated and pre-treated PEFB were determined.Pyrolysis of untreated and pre-treated PEFB individually was carried out using a fabricated fixed bed reactor system in nitrogen gas at a flow rate of 150 mL min -1 , pyrolysis temperature of 490 C with heating rate of 85 C min -1 for 210 s.A significant reduction of alkali and alkaline earth metals (AAEMs) and low oxygen content was observed on pre-treated EFB through demineralization and torrefaction pre-treatment.Pyrolysis of demineralized and torrefied EFB (TDPEFB) contributes about 59% of bio-oil, 29% of bio char and 12% of bio gas.Gas chromatography mass spectroscopy (GC-MS) on the bio-oil of pre-treated PEFB samples indicates that the chemical properties were improved.The quality of bio-oil derived from TDPEFB was enriched with ethers, furans, ketone and aldehyde and ester group.Polyaromatic hydrocarbon (PAH) and long chain fatty acid groups were also present with less oxygenated compounds in the group of phenols being detected.There are three factors that contribute to the quality of pyrolysis product yield of pre-treated PEFB i.e., the amount of AAEMs present in the biomass sample, decomposition of lignocellulose, and alteration of chemical structure of the biomass.From the overall results, the sequential pre-treatment of PEFB prior to pyrolysis is found beneficial to produce good quality bio-oil in a high quantity.