Pyrolysis and Gasification of Sugarcane Bagasse

Pyrolysis and Gasification of Sugarcane Bagasse

Yurancy Quinones, Akil Syed, Gautami Newalkar, Pradeep Agrawal, Carsten Sievers, and John Muzzy

School of Chemical & Biomolecular Engineering, Georgia Institute of Technology

Atlanta, Georgia 30332

     A major advantage of biomass gasification is that any type of biomass can be converted to syngas, making it attractive for unmerchantable wood, harvest residue, and waste from the forest and paper industry. Biomass gasification can be considered as two processes in series – biomass pyrolysis and char gasification. The goals of this research are to investigate the viability of using sugarcane bagasse as a renewable energy source by investigating the effect of temperature, pressure, and heating rate on char morphology in order to find optimum pyrolysis conditions for best char gasification reactivity.

     Chars were obtained through pyrolysis in a PEFR (Pressurized entrained flow reactor) at pressures ranging between 5-20 atm and at temperatures between 600-1000 ^oC. Chars were tested for reactivity in CO₂ using TGA (Thermogravimetic analysis) and analyzed using XRD (X-ray Diffraction) and SEM (Scanning Electron Microscopy) for char structure, and CO₂ and N₂physisorption for char surface area.

     An atmospheric pressure tubular quartz reactor was built to partially gasify the PEFR-generated chars and to examine the evolution of char morphology and surface area at various stages of conversion. The residual chars were tested again using the same techniques as described above. At both low and high pressures, increasing pyrolysis temperature leads to reduced char reactivity, however, the decrease is more pronounced at higher pressures. At both high and low pressures, increased temperature leads to the formation of less mesopores and macropores. SEM images of both low pressure low heating rate chars and high pressure high heating rate chars show that as pressure and heating rate are increased biomass swells and becomes more spherical unlike its low pressure and/or low heating rate fibrous counterpart. Furthermore, the XRD peak intensities at 2θ angles of 22° and 44° increased at higher pyrolysis temperatures, suggesting the formation of inactive graphitic carbon.