Fig. 1 shows that for particle size dp1 heated at 50°C/min, the amount of char left at the end of pyrolysis
process is 22.47% for EFB and 24.49% for OPT. Larger particle size decreases the amount of biomass
conversion whereby the final residue is 32.28 % and 25.35% for EFB and OPT respectively as shown in
Fig. 3. It is well agreed in the literature that larger particle sizes yields more residue because of poor heat
transfer to the inner biomass surfaces which leads to low average particles temperature [1,2]. Previous
study conducted by Sukiran et al. [3] shows that optimum bio-oil yield was obtained for particle size of
0.091-0.106 mm, and Ruengvilairat et al. [4] concluded that optimum EFB particle size is > 1.180 mm.
Larger particle size is favourable for char and gas production.