INTRODUCTION
Back ground of study
Malaysia has tremendous biomass resources from agricultural sector such as oil palm, paddy, sugarcane and rubber trees [1, 2] Among them, biomass from oil palm plantation and mill has the main contribution, and this solid biomass is predicted to reach 85-110 million tons by 2020 [2] Nowadays, the biomass residues are utilized for steam and power generation at mills, fiber material, pellets and fertilizer [3, 4] However, a certain big portion of biomass residues is not fully utilized, raising waste treatment and environmental pollution issues [5, 6]
The lignocellulose biomass resource can be used not only as direct energy in combustion, but also as a more valuable fuel after conversion and upgrading process [7] Thermal conversion of biomass is one of the prominent technologies to produce bio-char, bio-oil and bio-gas [7] In comparison with torrefaction or gasification, pyrolysis is conducted at moderate temperature (400600 ºC) and in the absence of oxygen [8] The pyrolysis oil (bio-oil) product has significant advantages in storage, transport and ability to utilize as useful petrochemical and fuel [9] In Malaysia, pyrolysis oil can be produced from different biomass feedstock such as palm kernel shell (PKS) [10, 11], empty fruit bunch (EFB) [12, 13], rice husk [14, 15] and wood sawdust [16] Interestingly, BTG (the coordinator of the EMPYRO project) has already constructed a 2 t/h pyrolysis plan using EFB as the feedstock [17]
Bio-oil is considered a promising second-generation biofuel and has been used to generate heat and electricity, e.g in combustors or turbines or as a co-feed in heat and power production plants However, it is very difficult to directly utilize the pyrolysis
2 oil because of its higher water (1634 wt%) and oxygen contents (3257 wt%) than heavy fuel oil (0.1 wt% and