Thermal decomposition of pyrolytic lignin under inert conditions at low temperatures

Interaction of Inherent Minerals with Carbon during Biomass Pyrolysis Weakens Biochar Carbon Sequestration Potential

“…37,39 Perhaps inherent minerals hindered the aromatization process via retaining more O-containing functional groups such as phenolic monomers or via hindering their release. 40 Stretching vibration of Si−O−Si groups (1041 and 800 cm −1 ) 37,41,42 were widespread in all the biochars, which seemed unaffected by demineralization, which is in accordance with the obvious diffraction peak of SiO 2 in the XRD curves (Figure S1). These results infer that inherent minerals perhaps have a negative effect on the formation of aromatic carbon.…”

“…Peaks at 1575 cm –1 , representing aromatic CC/CO, were higher in the demineralized biochars than in the original ones, especially in the cow manure biochar, which had the highest amount of minerals removal (Table ), ,, whereas this change was not obvious in sewage sludge biochar. A significant difference at peaks of 1405–1041 cm –1 was observed before and after the removal of inherent minerals, indicating that the absence of inherent minerals facilitated the disappearance of −CH 2 , C–O, and C–O–C. , Perhaps inherent minerals hindered the aromatization process via retaining more O-containing functional groups such as phenolic monomers or via hindering their release . Stretching vibration of Si–O–Si groups (1041 and 800 cm –1 ) ,, were widespread in all the biochars, which seemed unaffected by demineralization, which is in accordance with the obvious diffraction peak of SiO 2 in the XRD curves (Figure S1).…”

Coke Formation during Thermal Treatment of Bio-oil

“…This relates to the nature of bio-oil as bio-oil includes abundant organics containing oxygen. , The high oxygen content of bio-oil originates from the high oxygen abundance in biomass. The oxygen-containing organics in bio-oil have various functionalities such as ester groups, carbonyl groups, ether groups, carboxyl groups, phenolic functionalities, hydroxyl groups, etc. , The coexistence of the organics with this range of functionalities make bio-oil rather reactive toward polymerization/cracking, especially at elevated heating temperatures. ,,, Unfortunately, to upgrade bio-oil via reduction of the oxygen content (hydrotreatment) or the transformation of the reactive functionalities of bio-oil (esterification), bio-oil has to be heated to a certain temperature. Thus, the formation of coke is almost inevitable, imposing the substantial difficulty for the operation of the upgrading process, which also reduces the carbon efficiency from bio-oil to biofuels.…”

A Review on Biomass Gasification: Effect of Main Parameters on Char Generation and Reaction

“…Generally, the presence of tar has an adverse effect on the subsequent char gasification . The primary tar may take up to more than 20% of the volatiles from initial biomass pyrolysis and further go through a series of secondary reactions to condense as solid carbon on the surface of nascent char, which will cause pore blockage and cover the active carbon sites. − Besides, the extent of soot formation on char is greatly affected by the surface property (e.g., amorphous carbon structure and the abundance of AAEM species) of the char, as well as the condensation characteristics of bio-oil. − Tar cracking also generates some small fragments containing abundant active radicals over the char surface and in turn inhibits the access of gasifying reagents. This process can become more complex when involving catalytic interactions with char (including the carbon matrix and inorganics).…”