Optimization studies on bio-oil yield using microwave-assisted pyrolysis of bio-sludge

In this study, bio-sludge from a vegetable oil refinery effluent treatment plant was taken. The Proximate, ultimate, and elemental analyses of bio-sludge were done. Microwave-assisted fast pyrolysis using Box-Behnken design response surface methodology was applied to investigate the optimum conditions to produce high bio-oil from bio-sludge using activated carbon as microwave absorbent. The bio-oil obtained at the optimal condition was characterized using Fourier Transform infrared (FT-IR) spectroscopy and gas chromatography-mass spectrometry (GC/MS). It was found that the optimum bio-oil yield of 37.40% was estimated at the microwave power of 560W, the particle size of 4mm, and the microwave absorbent quantity of 1g. The gross calorific value of 18.6MJ/kg and a viscosity of 3.2mPa Sat 40 degrees C were obtained for bio-oil.