TY - JOUR
T1 - Hydrotreatment of pyrolytic lignins to aromatics and phenolics using heterogeneous catalysts
AU - Figueirêdo, M. B.
AU - Jotic, Z.
AU - Deuss, P. J.
AU - Venderbosch, R. H.
AU - Heeres, H. J.
PY - 2019/6/15
Y1 - 2019/6/15
N2 -
The pyrolysis of lignocellulosic biomass generates a liquid product, known as pyrolysis oil, that can be further processed into biofuels and value-added chemicals. During pyrolysis, cellulose and hemicelulose fractions are converted into a range of water-soluble sugar derivatives, for which several valorisation strategies exist. On the other hand, lignin is broken down into so-called pyrolytic lignin, a water-insoluble complex mixture of aromatic oligomers that requires different upgrading strategies than the sugar rich fraction. Here, we report an experimental study on the valorisation of pyrolytic lignin via catalytic hydrotreatment in the absence of an external solvent. A variety of carbon-supported noble-metal heterogeneous catalysts were tested (Ru/C, Pd/C, Pt/C and Rh/C), as well as conventional hydrotreatment catalysts (sulphided NiMo/Al
2
O
3
and CoMo/Al
2
O
3
) to obtain valuable low molecular weight aromatic and phenolic compounds. Overall, depolymerized liquids were obtained with organic yields of up to 63 wt%. Pd/C was shown to be the best catalyst, yielding 59 wt% of monomers based on the organic product (i.e. 33 wt% based on pyrolytic lignin intake). While noble metal catalysts favored higher monomer yields, though with some over-reduction of aromatic rings to saturated hydrocarbons, sulphided catalysts were more efficient in deoxygenation and aromatization reactions, but yielded less monomers. The hydrocracking efficiency was shown to be strongly dependent on the reaction temperature. Based on the experimental data, a global reaction network is proposed. The high monomer yields reveal the potential of catalytic hydrotreatment for the upgrading of pyrolytic lignin into valuable phenolics and aromatics.
AB -
The pyrolysis of lignocellulosic biomass generates a liquid product, known as pyrolysis oil, that can be further processed into biofuels and value-added chemicals. During pyrolysis, cellulose and hemicelulose fractions are converted into a range of water-soluble sugar derivatives, for which several valorisation strategies exist. On the other hand, lignin is broken down into so-called pyrolytic lignin, a water-insoluble complex mixture of aromatic oligomers that requires different upgrading strategies than the sugar rich fraction. Here, we report an experimental study on the valorisation of pyrolytic lignin via catalytic hydrotreatment in the absence of an external solvent. A variety of carbon-supported noble-metal heterogeneous catalysts were tested (Ru/C, Pd/C, Pt/C and Rh/C), as well as conventional hydrotreatment catalysts (sulphided NiMo/Al
2
O
3
and CoMo/Al
2
O
3
) to obtain valuable low molecular weight aromatic and phenolic compounds. Overall, depolymerized liquids were obtained with organic yields of up to 63 wt%. Pd/C was shown to be the best catalyst, yielding 59 wt% of monomers based on the organic product (i.e. 33 wt% based on pyrolytic lignin intake). While noble metal catalysts favored higher monomer yields, though with some over-reduction of aromatic rings to saturated hydrocarbons, sulphided catalysts were more efficient in deoxygenation and aromatization reactions, but yielded less monomers. The hydrocracking efficiency was shown to be strongly dependent on the reaction temperature. Based on the experimental data, a global reaction network is proposed. The high monomer yields reveal the potential of catalytic hydrotreatment for the upgrading of pyrolytic lignin into valuable phenolics and aromatics.
KW - Biobased chemicals
KW - Catalytic hydrotreatment
KW - Heterogeneous catalysts
KW - Pyrolytic lignin
KW - WATER-INSOLUBLE FRACTION
KW - SUPPORTED NIMO
KW - HYDRODEOXYGENATION
KW - OIL
KW - HYDROCRACKING
KW - CARBONYL
KW - FUELS
KW - COMO
UR - http://www.scopus.com/inward/record.url?scp=85062428417&partnerID=8YFLogxK
U2 - 10.1016/j.fuproc.2019.02.020
DO - 10.1016/j.fuproc.2019.02.020
M3 - Article
AN - SCOPUS:85062428417
SN - 0378-3820
VL - 189
SP - 28
EP - 38
JO - Fuel processing technology
JF - Fuel processing technology
ER -