To promote biomass-derived tar and coke upgrading, biomass pyrolysis intensification was utilized by the co-pyrolysis of biomass and caking coal with suitable particle size. The intensification led to a 15% increase in light tar fraction in tar, indicating a transformation from heavy tar to light components (phenols, aliphatic hydrocarbons). Moreover, the resulting coke achieved high strength (M25 > 80%) that can meet the requirement for moving bed gasification. To further facilitate tar upgrading and alleviate secondary reactions of volatiles that result in more secondary-coke and less gas, calcium-based Ca@Cu catalysts were synthesized and then loaded along the predicted coke cracks to improve tar quality without compromising coke granularity and strength. The results indicated that the catalytic upgrading mitigated the formation of pyrolytic water and secondary-coke, and dramatically improved tar quality as the light tar fraction in tar increased by 15–30%. Specifically, the upgraded light tar contains more phenols, naphthalenes, and anthracenes but less acids, ketones, and furfurals. It was postulated that selective cleavage of oxygen-containing functional groups (mainly ether bonds) promoted tar reconstruction to release more light aromatics during the catalysis. The coke strength continued to increase by 3–6%, possibly due to mitigation of H2O formation as indicated by more oxygen-containing groups retained in the aromatics during the Ca@Cu catalysis. The current study provided a new strategy to simultaneously upgrade coke and tar during catalytic pyrolysis of biomass for efficient utilization of the biomass.
Dandan Luo,Lan Yi,Jialing Chen,Hao Luo,Yuncai Song,Yi Huang,Xiaoqin Wu,Wen-Ying Li
The upgrading of coal-based fuels by eliminating acidic phenols and basic N-heterocyclic compounds is key to generating clean fuels, yet their simultaneous elimination is still a formidable challenge. According to this research, a tetraethylammonium chloride/oxalic acid (TEAC/OA) deep eutectic solvent (DES) realizes high simultaneous extraction efficiencies (>97 %) and a synergistic promotion: m -cresol’s extraction efficiency is increased from 90.6 % to 97.5 % by the presence of quinoline. In order to reveal the origin of this high performance, the integration between multi-scale simulations and spectroscopic analysis was conducted. The findings reveal that the high performance is caused by a complex “division-of-labor” system, where the Cl – anion anchors m -cresol while the quinoline is sequestered by the TEA + and OA. This selective capture is thermodynamically boosted, with the target molecules showing greater calculated interplay energies than the oil matrix. A near two-order-of-magnitude reduction in the diffusion parameters of the target molecules upon extraction further confirms the merit of this molecular “caging”. This research shows an effective method to purify complicated fuel oils and set up a novel principle of synergistic design for next-generation extractive separation media.
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