To produce palm kernel shell (PKS) biocrude oil, a bubbling fluidized bed pyrolyzer was used with different sample sizes and reaction temperatures. The PKS sample sizes used were 0.1 ~ 0.4 mm, 0.4 ~ 1.0 mm, and 1.0 ~ 2.0 mm and the reaction temperature were 465oC, 490oC, 530oC, 560oC, and 590oC. The yield of PKS biocrude oil increased with decreasing the sample size. The maximum yield of PKS biocrude oil was 47.31% at 560oC with a PKS sample size of 0.1 ~ 0.4 mm. In addition, the maximum energy yield of PKS biocrude oil was 45.05% at 560oC and size 0.1 ~ 0.4 mm. Among the characteristics of PKS biocrude oil, the high heating values are from 15.98 MJ/Kg to 20.29 MJ/Kg, the moisture content is from 20.14wt.% to 31.57wt.%, and the viscosity ranges from 0.0117 N s/m2 to 0.0408 N s/m2. In addition, proximate analyses and elemental analysis of PKS biocrude oil were conducted.
The optimum design and scale-up of a fast pyrolysis reactor require a fundamental understanding of its hydrodynamics characteristics. Extensive investigations have been carried out, both theoretically and experimentally, to understand the hydrodynamic characteristics of gas-solid two-phase flow in a pyrolysis reactor, such as velocity field, solids concentration, and pressure drop. Numerical simulation can provide a promising alternative for studying the hydrodynamics of gas-solid flows in the fast pyrolysis reactor. In this study, computational particle fluid dynamics (CPFD) was used to investigate the hydrodynamic characteristics of bubbling fluidized bed (BFB) and conical spouted bed (CSB) reactors. These characteristics were analyzed in terms of pressure drop, solid distribution, and solid circulation rate. The BFB reactor was found to have a lower efficiency than the CSB reactor. The pressure drop of the CSB reactor was 25% less than that of the BFB reactor. The solid circulation rate of the CSB reactor was 68% greater than that of the BFB reactor.