TY - JOUR

T1 - Effect of Ceria Addition to Na2O-ZrO2 Catalytic Mixtures on Lignin Waste Ex-Situ Pyrolysis

AU - Yeardley, Adam

AU - Bagnato, Giuseppe

AU - Sanna, Aimaro

PY - 2021/2/5

Y1 - 2021/2/5

N2 - Waste lignin is a potential source of renewable fuels and other chemical precursors under catalytic pyrolysis. For this purpose, four mixed metal oxide catalytic mixtures (Cat) derived from Na 2CO 3, CeO 2 and ZrO 2 were synthesised in varying compositions and utilised in a fixed bed reactor for catalytic vapour upgrading of Etek lignin pyrolysis products at 600 °C. The catalytic mixtures were analysed and characterised using XRD analysis, whilst pyrolysis products were analysed for distribution of products using FTIR, GC-MS and EA. Substantial phenolic content (20 wt%) was obtained when using equimolar catalytic mixture A (Cat_A), however the majority of these phenols were guaiacol derivatives, suggesting the catalytic mixture employed did not favour deep demethoxylation. Despite this, addition of 40-50% ceria to NaZrO 2 resulted in a remarkable reduction of coke to 4 wt%, compared to ~9 wt% of NaZrO 2. CeO 2 content higher than 50% favoured the increase in conversion of the holo-cellulose fraction, enriching the bio-oil in aldehydes, ketones and cyclopentanones. Of the catalytic mixtures studied, equimolar metal oxides content (Cat_A) appears to showcase the optimal characteristics for phenolics production and coking reduction.

AB - Waste lignin is a potential source of renewable fuels and other chemical precursors under catalytic pyrolysis. For this purpose, four mixed metal oxide catalytic mixtures (Cat) derived from Na 2CO 3, CeO 2 and ZrO 2 were synthesised in varying compositions and utilised in a fixed bed reactor for catalytic vapour upgrading of Etek lignin pyrolysis products at 600 °C. The catalytic mixtures were analysed and characterised using XRD analysis, whilst pyrolysis products were analysed for distribution of products using FTIR, GC-MS and EA. Substantial phenolic content (20 wt%) was obtained when using equimolar catalytic mixture A (Cat_A), however the majority of these phenols were guaiacol derivatives, suggesting the catalytic mixture employed did not favour deep demethoxylation. Despite this, addition of 40-50% ceria to NaZrO 2 resulted in a remarkable reduction of coke to 4 wt%, compared to ~9 wt% of NaZrO 2. CeO 2 content higher than 50% favoured the increase in conversion of the holo-cellulose fraction, enriching the bio-oil in aldehydes, ketones and cyclopentanones. Of the catalytic mixtures studied, equimolar metal oxides content (Cat_A) appears to showcase the optimal characteristics for phenolics production and coking reduction.

KW - Bioethanol waste

KW - Catalysis

KW - Ceria

KW - Lignin

KW - Metal oxides

KW - Phenol

KW - Pyrolysis

KW - ZrO2

U2 - 10.3390/molecules26040827

DO - 10.3390/molecules26040827

M3 - Journal article

C2 - 33562554

VL - 26

JO - Molecules

JF - Molecules

SN - 1420-3049

IS - 4

M1 - 827

ER -