JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2024
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IF 5.8
Ji Liu,Hao Fu,Bin Hu,Guan-zheng Zhou,Shou-gang Wei,Zhen-xi Zhang,Qiang Lu
Pyrolysis, a promising thermochemical conversion technique, can convert lignocellulosic biomass into various value-added products. Herein, the selective production of 1,4:3,6-dianhydro-α- d -glucopyranose (DGP) was achieved through fast pyrolysis of cellulose based on oxalic acid-assisted torrefaction (OAT) pretreatment. The mixture of cellulose and oxalic acid first underwent torrefaction, followed by fast pyrolysis to yield DGP. Simultaneously, the air atmosphere was considered to facilitate the formation of esterification intermediates, thereby promoting the formation of DGP. The effects of torrefaction temperature, oxalic acid amount, as well as pyrolysis temperature were carefully explored for DGP production. A yield of 9.6 wt% and a selectivity of 57.5 % for DGP were achieved from the micro-scale pyrolysis of cellulose under the optimized conditions. In lab-scale tests, the DGP yield reached 12.5 wt% from cellulose. The OAT-based pyrolysis was confirmed to be applicable to the waste cellulose-rich materials, with a DGP yield of 8.2 wt% from waste cotton and 6.0 wt% from spent paper in lab-scale experiments. Additionally, the OAT-based pyrolysis also showed the potential for poly-generation of DGP and formic acid at different stages.
研究领域:
能源与燃料化学
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生物质转化技术
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产品关联
DOI
高影响因子
FUEL
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2025
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IF 7.5
Binbin Chen,Hong Tian,Zhen Zhou,Yanni Xuan,Zhijie Wang,Siying Liu
A combined pretreatment of straw was carried out using acid washing and torrefaction methods. Metal-modified HZSM-5 core–shell molecular sieves were prepared by loading Zn (2, 4, and 6 wt%) and Ni (6, 8, and 10 wt%) on HZSM-5 molecular sieves and introducing MCM-41 core–shell structure. PY-GC/MS and a tubular furnace were employed to study the effects of pretreatment conditions and catalysts on the product composition distribution during wheat straw catalytic pyrolysis. XRD, SEM, BET, TPD and ICP were used to characterize the catalyst performance. It was found that the combined acid washing and torrefaction pretreatment reduced the oxygenated compounds in the bio-oil from straw catalytic pyrolysis and increased the bio-oil yield to 29.37 %. The incorporation of modified catalysts promoted the deoxygenation, zwitterionization and aromatization reactions during the straw-catalyzed pyrolysis. The monometallic loading of 4%Zn/HZ and 8%Ni/HZ catalyzed acid washing and torrefaction straw pyrolysis resulted in 54.2 % and 57.06 % yields of MAHs and 42.86 % and 38.58 % yields of BTX in bio-oil, respectively.Compared with the monometallic loading, 4%Zn8%Ni/HZ further optimized the bio-oil compositional distribution, with a MAHs yield of 64.76 %, a BTX yield of 54.69 %, and a deoxygenation performance of 81.34%.MCM-41-coated HZSM-5 produces a large mesoporous structure with channels with sufficient transport capacity, accelerating the cleavage of various types of oxygen-containing compounds in the bio-oil into smaller molecules for better conversion into aromatics. The 4%Zn8%Ni/H@M catalyst achieved a MAHs yield of 72.68 % and BTX yield of 63.43 % in the bio-oil during pyrolysis of acid-washed and torrefied wheat straw, with oxygen removal efficiency reaching 85.37 %. Therefore, the combination of feedstock pretreatment and metal-modified core–shell HZSM-5 molecular sieve could synergistically optimize both compositional distribution and production yield of bio-oil derived from biomass pyrolysis.
研究领域:
催化化学
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生物质能源
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材料科学
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环境工程
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绿色化学
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产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
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2022
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IF 6.47
Yunwu Zheng,Donghua Li,Jida Wang,Yifei Chen,Can Liu,Yi Lu,Xu Lin,Bohan Lv,Jirong Li,Zhifeng Zheng
To investigate the nitrogen migration and transformation mechanisms that produce high value-added N-containing chemicals, the NH 3 /N 2 torrefaction pretreatments of waste biomass for the production of renewable N-containing compounds were explored, and the effects of torrefaction temperature (200, 225, 250, 275, 300 °C) on fuel properties, structure, crystallinity , surface functional groups and thermal kinetics were evaluated by element analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), fourier infrared spectroscopy (FTIR) and thermogravimetric analysis (TG-DTG). The effects of subsequent catalytic ammonization pyrolysis upgrading of the torrefied biomass with Co/HZSM-5/HZSM-5 catalysts under an NH 3 /N 2 atmosphere on product yield and N-containing compound selectivity were also evaluated with GC/MS and UV-fluorescence spectrometry. Furthermore, nitrogen fixation and migration mechanisms were also proposed in depth. The results showed that NH 3 torrefaction was more effective in enhancing N fixation and retarding the release of N-containing volatiles in torrefied biochar (0.26%–9.43%) and reducing the oxygen content (43.18%–21.81%) via Maillard reactions compared with N 2 torrefaction. With increasing torrefaction severity, the N-containing compound content, higher heating values (HHV), deoxygenation ratio (DEO) and nitrogen-doping ratio (NDR) increased, which were much higher than those of conventional N 2 torrefaction. Higher temperatures promoted the evolution of graphitic-N and oxidized-N and reduced pyrrolic-N and pyridinic-N group formation in torrefied biochar. The maximum content of N-containing compounds of 88.71% was obtained at a torrefaction temperature of 275 °C under NH 3 pyrolysis coupled with the Co/HZSM-5 catalyst, and was achieved via substrate interaction with the -Co-O-Si- catalyst sites and Maillard reactions. Furthermore, the N 2 atmosphere combined with the HZSM-5 catalyst significantly promoted the conversion of HC compounds (∼56.97% at 225 °C during N 2 torrefaction), while the Co/HZSM-5 catalyst combined with the NH 3 atmosphere significantly improved N-containing compound formation. NH 3 pyrolysis facilitated the formation of pyrroles and pyrazines while reducing the formation of amides by deamination and dehydrogenation reactions. Cellulose was conducive to the transformation of pyrrole in NH 3 pyrolysis, while lignin was conducive to the formation of aniline. These results could offer strategies to regulate nitrogen functional groups to enhance N-containing chemicals.
研究领域:
能源与环境科学
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化学工程
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产品关联
DOI
高影响因子
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