Effects of Temperature and Catalysts on the Yield of Bio-oil During the Pyrolysis of Spirulina platensis Residue

Spirulina platensis (SP) is an aquatic biomass potentially grown as an energy source in the future. Extracting algae oil from SP extraction will leave solid residue called Spirulina platensis residue (SPR). In this study, SPR was processed through pyrolysis process, both catalytic and non-catalytic. The use of the catalyst in the SPR pyrolysis process can affect pyrolysis product composition. This study focused on the effects of different catalysts on the yield of bio-oil obtained from pyrolysis process. Pyrolysis experiments were conducted at a temperature range of 300 – 600 ºC using three different catalysts: Ni oxide, Fe oxide, and silica-alumina. Catalytic pyrolysis was conducted at 550 oC in various amounts of 5-30% for each catalyst. The effect of temperature on SPR catalytic and non-catalytic pyrolysis was studied. The result shows that the optimum yield of non-catalytic pyrolysis was 27.34 wt.% at 550ºC. The yield of bio-oil with in catalytic pyrolysis indicates that the maximum pyrolysis oil was obtained using Fe oxide as catalyst with 30.00 wt.% bio-oil, followed with 23.37 wt.% using Ni oxide catalyst, and 18.41 wt.% using silica-alumina catalyst. The water phase yield for each catalyst was relatively different for every catalyst in various amount ranging from 5-30%. Char and gas yields were almost the same for each type of catalyst in all amount variations. The highest gas yield produced was using silica-alumina catalyst, followed by Fe oxide and Ni oxide catalyst. The SPR catalytic pyrolysis process improves the bio-oil yield with the increasing of the bio-oil yield 2.66 wt.% compared to the SPR non-catalytic pyrolysis.