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[Display omitted] • A green and effective strategy for biomass valorization was proposed. • Citric acid (CA) washing promoted furfural production during the torrefaction step. • CA washing increased levoglucosan yield to 3.76 times for W250-FP compared to R250-FP. • Torrefaction reduced acetic acid yield by 65% for W250-FP compared to WRaw-FP. Converting agricultural waste biomass into value-added chemicals is attractive. However, a low selectivity for target chemicals hinders practical applications. This study presents a stepwise strategy to convert sugarcane trash (ST) into furfural and levoglucosan with high selectivity. The approach includes citric acid washing to reduce mineral content in ST, followed by torrefaction at different temperatures (210 °C, 250 °C and 290 °C) in a tube furnace and then fast pyrolysis at 500 °C in a micro-reactor. This study highlights the valorization potential of the torrefaction liquid, an often overlooked by-product from torrefaction, through significantly increasing furfural selectivity during the torrefaction of washed ST. Furthermore, the vapors from subsequent fast pyrolysis of washed-torrefied ST exhibited reduced acetic acid content compared to that of solely washed ST, which is advantageous for minimizing the acidity of the resulting bio-oil. Moreover, fast pyrolysis of ST, treated with washing and torrefaction at 250 °C, achieved a high levoglucosan yield while maintaining a high furfural yield obtained in the prior torrefaction step. The findings of this study provide valuable insights into future research and industrial applications in agricultural waste biomass utilization. [ABSTRACT FROM AUTHOR]

This study outlines the effect of citric acid leaching on the quality and stability of fast pyrolysis bio-oils from sugarcane bagasse (SCB) and sugarcane trash (SCT). The quality of bio-oil was probed by GC-MS analysis, elemental composition, higher heating value, water and solids content, pH, dynamic viscosity and stability (ageing). Pyrolysis was performed at 500 °C in a fully controlled, continuously operated plant with a biomass throughput of ca. 300 g.hr−1. While citric acid leaching causes a decrease of the average bio-oil yield with 5%, it does not lead to a bio-oil with improved fuel-related properties. However, the bio-oil composition became more advantageous in light of its biorefining. Indeed, citric acid leaching led to an increased levoglucosan concentration – a promising platform chemical – of 17% for SCB and of to 35% for SCT (based on relative abundance in GC-MS). In tandem, the concentration of carboxylic acids and phenols in the bio-oil decreased after citric acid leaching, which is beneficial for downstream purification of levoglucosan. Regarding the non-condensable gases, CO and CO 2 represented between 88% and 91% by weight of the total non-condensable gases produced in pyrolysis. Therefore, the results of this study demonstrate that optimized biomass demineralization pretreatment with citric acid could produce bio-oil at high yield and rich in high-value chemical compounds like levoglucosan. Biomass demineralization pretreatment however, does not result in bio-oil with improved quality for fuel purposes, nor does it necessarily lead to bio-oil having higher stability. • Mild pretreatment with CA is effective in ash removal in sugarcane residues. • CA pretreated feedstock has higher bio-oil yields on pretreated feedstock basis. • Fresh/aged trash derived bio-oils have lower viscosity than bagasse derived bio-oils. • CA pretreatment holds no major benefit for bio-oil composition in terms of fuel use. • Major increase in anhydrosugar content after mild CA pretreatment of sugarcane residues. [ABSTRACT FROM AUTHOR]