LIGNIN UPGRADING VIA THERMAL AND CATALYTIC PYROLYSIS – LIGNIN NATURE EFFECT

摘要

In this work thermal and catalytic lignin pyrolysis with a commercial ZSM-5 were studied aiming at the productionrnof fuels and high added value chemicals such as phenols. The lignin feedstocks were byproducts received byrnorganosolv treatment of various Greek agricultural residues. For comparison purposes pyrolysis of Kraft lignin is alsornpresented. Agricultural residues (cotton and corn stalks, wheat and barley straw) and a woody biomass (beechwood)rnwere treated with the Milox process that has been found to be an effective way of removing lignin from biomass andrnincreasing the fermentability of the remaining cellulose. Single stage Milox was carried out with Formic acid (FA),rnAcetic acid (AA) and their mixtures. Lignin pyrolysis took place in a bench scale fixed bed unit. The results showedrnthat in the case of the agricultural residues, the lignin received from corn stalks presented the highest oil yield, aroundrn15 wt.% on dry feedstock, while in all cases high CO_2 yield was noted. Wet oxidation lignin (WO) was alsornpyrolyzed and found to produce higher lignin oil with a lower oil O_2. WO lignin was pyrolyzed with the addition ofrnsolid acid catalysts and oil quality improved to the expense of the oil yield.