Catalytic pyrolysis of perennial shrub, Euphorbia rigida in the water vapour atmosphere

In this study, the perennial shrub Euphorbia rigida, was used as biomass sample for catalytic pyrolysis using Co-Mo commercial catalyst (Criterion-534) in the water vapour atmosphere. Experimental studies were conducted in a well-swept fixed-bed Heinze reactor with a heating rate of 7 degrees C min(-1), a final pyrolysis temperature of 550 degrees C and a mean particle size of 0.55 mm. The catalyst was mixed with feedstock in different percentages. The catalyst ratio used were 0% (no catalyst) 5, 10, 20 and 25% (w/w) under saturated water vapour atmosphere with well-swept velocities of 0.0, 0.6, 1.3 and 2.7 cm/s to determine the effect of catalyst and water vapour on product yields and bio-oil composition. Yield of bio-oil did not increase much with more use in catalyst but yields of 42.6% was routinely obtained using catalyst ratio of 20% and water vapour flow rate of 1.3 cm/s. Without water vapour oil yield drop to 30.98%. Pyrolysis oils were examined by using IR and H-1 NMR spectroscopy. The liquid products were also fractionated by column chromatography. More polar fraction and less substituted aromatics and aliphatics were obtained when water vapour was used. The gas chromatographic analysis of n-pentane eluates was performed. According to the results obtained in this study, it is possible to produce petroleum-like liquid pyrolysis products by catalytic pyrolysis of E. rigida in the presence of water vapour. (c) 2005 Elsevier B.V. All rights reserved.