Study on characteristics of carbonyl compounds from pyrolysis of holocellulose catalyzed by coal gasification fine slag

LIU Yuan; CHEN Jialong; SUN Zhenjie; YANG Chen; GUO Feiqiang; WU Songtao; YOU Xiaodong; XIONG Mingjie; LI Zhenming

doi:10.13225/j.cnki.jccs.2025.0398

Abstract：The resource utilization of biomass and coal gasification fine slag(CGFS)is considered crucial for ensuring na-tional energy security,mitigating environmental pollution,and achieving China's"dual carbon"target.Pyrolysis,as the fundamental thermochemical conversion of biomass,enables the rapid transformation of biomass into bio-oil,biochar,and small-molecule gases within milliseconds,representing one of the most promising technologies for high-value biomass utilization.However,direct application of bio-oil is hindered by its complex composition and poor stability.The conver-sion pathways of biomass pyrolysis vapors are dynamically regulated through ex-situ catalytic fast pyrolysis technology,thereby enhancing carbonyl compound content in bio-oil.This carbonyl-enriched bio-oil serves as a critical platform inter-mediate for synthesizing gasoline/diesel and lubricants via aldol condensation and reductive etherification reactions.Nev-ertheless,existing catalysts are constrained by complex synthesis procedures and prohibitive costs.Thus,CGFS was in-novatively employed in biomass catalytic fast pyrolysis,and a novel strategy termed"holocellulose rapid pyrolysis coupled with CGFS-directed catalysis"was proposed for producing carbonyl-enriched bio-oil,achieving synergistic utiliz-ation of biomass and CGFS.Systematic investigations were conducted using corn stalk holocellulose as feedstock and CGFS as catalyst through ex-situ fast catalytic pyrolysis.The effects of pyrolysis temperature,catalytic temperature,and catalyst-to-feedstock mass ratios on product distribution and composition were comprehensively analyzed.Catalyst char-acterization was performed using XRD,SEM-EDS,and XPS,with additional evaluation of cycling stability and regenera-tion capacity.Key findings demonstrated that:Bio-oil and biochar yields were reduced with increasing pyrolysis temperat-ure,peaking at 49.8％bio-oil yield at 450 ℃.A progressive decrease in bio-oil yield from 40.1％to 32.2％was observed as the catalytic temperature was elevated from 400℃ to 550 ℃,while gas yield was enhanced from 36.8％to 45.4％.This thermal transition was accompanied by significant increases in H2+CH4,CO2,and CO yields,rising from 5.3,40.7,and 53.1 mL/g to 57.2,55.9,and 124.3 mL/g,respectively.Increasing mass ratios of catalyst to holocellulose from 0.5 to 2 re-duced bio-oil yield from 46.6％to 36.2％,while CO2 and CO yields rose from 36.4 and 46.3 mL/g to 51.7 and 59.9 mL/g.A marked enhancement in carbonyl compound content was achieved through catalyst loading optimization,with relative abundance increasing from 48.9％to 81.9％as the catalyst-to-feedstock ratio was elevated from 0 to 2.Concurrently,ketonic species exhibited similar amplification from 41.4％to 81.2％.The carbonyl fraction was predominantly composed of linear ketones(e.g.,1-hydroxy-2-propanone),cyclic ketones(e.g.,2-cyclopenten-1-one),and furan derivatives includ-ing furfural and 5-hydroxymethylfurfural.Notably,peak area ratio of 1-hydroxy-2-propanone was elevated from 1.41％to 48.98％as the catalyst-to-feedstock ratio was elevated from 0 to 0.5.The crystallographic phases of CGFS remained un-altered after use,while the surface O and C atomic ratio was reduced.The fresh CGFS exhibited an Fe2+content of 60.08％,and the value decreased after use.After five catalytic cycles,carbonyl content declined from 75.7％to 67.6％,primarily attributed to oxidation of surface metallic species.