Calcium-catalyzed pyrolysis of lignocellulosic biomass components

Abstract

The present study examines the effect of calcium pretreatment on pyrolysis of individual lignocellulosic compounds. Previous work has demonstrated that the incorporation of calcium compounds with the feedstock prior to pyrolysis has a significant effect on the oxygen content and stability of the resulting oil. The aim of this work was to further explore the chemistry of calcium-catalyzed pyrolysis. Bench-scale pyrolysis of biomass constituents, including lignin, cellulose and xylan is performed and compared to the oils produced from pyrolysis of the same components after calcium pretreatment. The resulting oils were analyzed by quantitative GC-MS and SEC. These analyses, together with data collected from previous work provide evidence which was used to develop proposed reaction pathways for pyrolysis of calcium-pretreatment biomass.

Renewably sourced phenolic resins from lignin bio‐oil

“…The identified phenol, substituted phenols, and catechols in the bio‐oil account for 21.7 wt % of the oil with the balance of the materials being unidentified higher molecular weight compounds. Studies on FAsP pyrolysis of whole wood suggest that these compounds are oligomers of the lignin constituents and polyaromatic hydrocarbons originated during pyrolysis, that are not sufficiently volatile for GC analysis due to their high molecular weight . Methoxy‐functionalized phenolics such as guaiacol, syringol, and their derivatives were not detected in these oils, which is consistent with previous results .…”

“…Further, the oxygen to carbon ratio (O/C) of the product as compared to lignin deceased from 0.19 to 0.17 reflecting the deoxygenation, while the hydrogen to carbon ratio (H/C) increased from 0.96 to 1.13, confirming that the calcium formate helped hydrogenate the products . Some batch to batch variability exists for the pyrolysis of lignin as some compounds are present at higher concentrations in one reactor run as compared to the other, but in general the two runs yielded similar concentrations of identifiable compounds (23.1 wt % for run B, Supporting Information Table S1) with compositions consistent with previous reports on the FAsP of lignin . Of these identified compounds, nearly 50% of the mass is phenol and the three methyl phenols (cresols).…”

“…Following a modified literature procedure, the commercial lignin Indulin AT (MeadWestvaco, >400 µm particle size) was mixed with calcium formate in a 1:1.4 weight ratio of lignin to calcium formate in 600 mL of water to make a slurry that was oven dried at 100 °C for 24 h. The resultant material was ground and sieved to a particle size of less than 425 µm. Pyrolysis was conducted in a laboratory scale fluidized bed reactor with 100 g of sand as the heat transfer medium.…”

“…has reported a modified pyrolysis approach for lignin, formate assisted fast pyrolysis (FAsP), which overcomes the above issues . Furthermore, the decomposition of the formate salt during FAsP provides an in situ reactive hydrogen source that contributes to significant deoxyhydrogenation and promotes formation of phenol and alkyl phenols by removing methoxy functionality from the resultant bio‐oil . Such phenolic products are a significant improvement over conventional pyrolysis of pure lignin that generates a variety of methoxy‐substituted aromatic compounds …”

Experimental and kinetic study of steam gasification of low-rank coal in molten blast furnace slag

“…9. By the research results of the Case et al [40], the intermediate products of the pyrolytic volatiles (C x H y O z ) were difference when molten BFS existed. Polycyclic aromatic hydrocarbon (PAH) and phenols were formed by C x H y O z cracking when the coal pyrolysis reaction happened in molten BFS.…”