Assessment of the Effects of Hydrogen Pressure on Biomass Pyrolysis - a Study of Euphorbia-Rigida, Sunflower Oil, Industrial-Waste and Pure Cellulose

Abstract

To assess the effects of mass transfer and hydrogen pressure on the oil yield and quality from cellulosic biomass, fixed-bed pyrolysis (atmospheric pressure) and hydropyrolysis experiments at temperatures between 400 and 650 degrees C have been conducted on sunflower bagasse and pure cellulose. The Euphorbia Rigida was extracted with n-hexane and methanol to remove low molecular mass terpenoids and saccharides so as to elucidate the extent of oil formation and aromatisation from the cellulosic structure. In contrast to coals and oil shales, oil yields from the sunflower bagasse were found to be largely independent of particle size (<1.8 mm) and sweep gas velocity with ca 35-40% w/w oil (dry basis) being obtained at 450-500 degrees C. The use of high hydrogen pressures (> 50 bar) only gave rise to relatively small increases in oil yield but, expressed on a carbon basis, these increases are much greater due to the reduced the oxygen contents of the oils.