Conversion of Siam weeds and rice straws to energy products and valuable chemicals via pyrolysis

Increasing global warming has necessitated reduction in combustion of waste and encouraged their conversion into useful materials. Rice straw and Siam weed were valorised via pyrolysis in a laboratory-scaled modified slow pyrolysis reactor and products collected and characterised. The major product obtained was bio-char for both wastes with 12.3% and 27.8% viscous bio-oil recovered from the pyrolytic condensates of rice straw and Siam weed respectively. The resulting bio-oil is less acidic compared to most known pyrolytic oils. Separation of condensates reduced acidity and retarded ageing of bio-oils. The most abundant compound found in Siam weed viscous bio-oil from GC-MS analysis was phenol (16.93%) while it was pentadecyl-2-propyl ester sulphurous acid (30.37%) in rice straw. Bio-chars from these residues showed a higher heating value of ∼21 MJ/kg and pH values of ∼9.00.