(3e) In Situ Catalytic Fluid Bed Pyrolysis of Poplar Wood

Rising global economic, strategic and environmental concerns putting pressure on the use of more domestic and renewable energy options. On the other hand, the utilization nonfood lignocellulosic biomass is becoming more and more important as the negative effects of those already in the human and animal food chain as far as availability and costs are concerned. Pyrolysis is one of the thermochemical conversion method for producing solid, liquid and gas products in the utilization of biomass. Fast pyrolysis is particularly important for biooil production that can be further processed into fuels and chemicals. However, the direct substitution of biooils with petroleum derived fuels and chemicals derived via pyrolysis is not likely due to its complex, highly oxygenated nature and higher viscosity without applying any upgrading. The early bio oil upgrading research focused on the catalytic cracking of the biooils over an acid type fixed bed of catalyst resulting in quick catalyst deactivation due to coke formation. In this research the fractional catalytic pyrolysis of poplar wood chips (<1.0 mm) into bio oil was achieved by an efficient and one step in-situ catalytic process on bench scale. The pyrolysis product distributions and the bio oil composition were greatly altered by the method. An FCC catalyst was used as the fluidizing bed which facilitated fast pyrolysis and instantaneous selective cracking simultaneously of the biomass. The average product distribution was 27.3 ±1.2% for liquid, 20.6 ±1.4% for the char and 52.2 ± 0.2% for the gas based on dry and ash free basis of the feed. On the other hand, the liquid, char and gaseous product yields obtained from conventional fast pyrolysis of poplar chips by using sand as the fluidization medium were 43.6±2.0 %, 14.9±2.5% and 41.5±1.2% respectively. The oil yield calculations based on including pyrolysis water but excluding amount of moisture available in the feed. The gas (syngas) composition was screened using a gas chromatograph connected online for the determination of CO, CO₂ and C₂-C₆ range of parafins and olefins using a Hayesep-D column and a flame ionization dedector equipped with methanizer. The elemental composition, calorific value, viscosity, density and molecular weight distribution of the biooil were also determined. The ¹³C nmr data of the produced biooil revealed that the in-situ catalytic process is capable of producing a narrower range of chemicals vast majority of which were highly aromatic as compared to conventional fast pyrolysis biooil.