Jiao Chen,Chao Liu,Shubin Wu,Jiajin Liang,Ming Lei
Black liquor is an attractive option for the generation of biofuel and fine chemical intermediates. In this work, kraft lignin was extracted from black liquor and its potential was evaluated in the production of high quality bio-oil via catalytic pyrolysis under two different reaction regimes (N2 and 10% H2 in N2). The 2D HSQC NMR result showed that the lignin obtained directly through acidic precipitation with CO2 mainly consisted of syringyl lignin units and cross-linked C–C bond substructures. The thermal decomposition of the sample mainly occurred at 200–500 °C and the char yield was 44.46% at 700 °C. The catalytic pyrolysis experiment indicated that the addition of catalysts (NiO, MoO2, and Co3O4) could inhibit char formation and enhance the properties of bio-oil by removing oxygenated compounds via releasing CO and CO2 under a N2 atmosphere. The addition of the catalysts could prompt lignin degradation and increase the yield of bio-oil in the presence of H2. The yield of bio-oil increased by 26.38% with Co3O4 catalytic pyrolysis under a H2/N2 atmosphere.
Qiang Lu,Xiao-ning Ye,Zhen-xi Zhang,Ze-xiang Wang,Min-shu Cui,Yong-ping Yang
Activated carbon (AC) prepared by physical activation with steam (named as AC-H 2 O) was employed for catalytic fast pyrolysis of bagasse in a hydrogen atmosphere to selectively produce 4-ethyl phenol (4-EP), a valuable phenolic compound. Lab-scale fast pyrolysis experiments were conducted to quantitatively determine the pyrolytic products and investigate several factors on the 4-EP production, including pyrolysis atmosphere, AC type, catalytic pyrolysis temperature, and AC-to-bagasse ratio. The results indicated that the AC-H 2 O (activated by H 2 O) catalyst exhibited much better performance on 4-EP production than other ACs prepared by different activation methods. Compared with the inert atmosphere, the presence of hydrogen atmosphere could significantly promote the 4-EP formation with the yield increase by over 36%. The maximal 4-EP yield of 3.55 wt% with the selectivity of 17.42% was obtained under AC-to-bagasse ratio of 1.5 at 330 °C. In addition, the gas product produced by the pyrolysis process could be recycled to provide a hydrogen atmosphere without an additional hydrogen supply.
Zhen-xi Zhang,Kai Li,Shan-wei Ma,Min-shu Cui,Qiang Lu,Yong-ping Yang
Phenol is an important phenolic compound widely used in chemical industry. Lignin in lignocellulosic biomass materials has been recognized as a renewable source for phenol production due to its aromatic nature. In the present study, phenol was selectively prepared from fast pyrolysis of biomass using a recyclable magnetic solid base catalyst (K 3 PO 4 /Fe 3 O 4 , MSB) in an atmosphere with low hydrogen content. The study focused on the influence of pyrolysis atmosphere, pyrolysis temperature, catalyst content, and biomass type on the product distribution, as well as the recycle performance of MSB in consecutive pyrolysis experiments. Results suggested that the synergistic effect of MSB catalyst and hydrogen atmosphere significantly improved the formation of phenol. In a hydrogen atmosphere at MSB to biomass ratio of 1, the maximal phenol yield of 4.3 wt% with the selectivity of 17.6% was obtained from poplar wood pyrolysis at 550°C. Pyrolysis experiments with different biomass materials suggested that the phenol formation was positively correlated with biomass lignin content. A three consecutive run experiment indicated that the MSB catalyst had excellent performance on recovery and recycle. In addition, possible synergistic mechanism between MSB and hydrogen atmosphere was proposed.
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