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In this study, iron was used to modify pyrolytic activated carbon (AC) to synthesize a bifunctional catalyst (Fe/AC). It was applied to the catalytic co-pyrolysis of lignin with polypropylene (PP) for the preparation of jet fuel range hydrocarbons. Relationships between iron loading, reaction temperature, catalyst/feedstock ratio, and lignin/PP ratio were investigated in connection to the yield, component distribution, carbon number distribution, and chain structure of pyrolysis products. The results indicated that the hydrocarbons with carbon numbers in the jet fuel range dominated the products obtained from the catalytic co-pyrolysis of lignin and polypropylene. Owing to the oxytropism of Fe3 + , the selectivity of oxygenated chemicals in pyrolysis oil decreased as the Fe loading rose. Consequently, the production of hydrocarbons in the jet fuel range was increased. Furthermore, the deoxygenation and alkylation reactions of phenols to high-carbon aromatics were facilitated by Fe3 +. The cyclization and dehydrogenation reactions were promoted with the reaction temperature increased, thus enhancing the selectivity of cyclic hydrocarbons (cycloalkanes and aromatics) in the jet fuel range. However, secondary reactions were boosted with the excessive temperature, reducing the yield of hydrocarbons and the percentage of high-carbon hydrocarbons in the jet fuel range. The reduction of the proportion of oxygenated compounds was facilitated by the use of catalysts. Thus, the selectivity of hydrocarbons in the jet fuel range was improved, but the yield of high-carbon hydrocarbons would be reduced. In addition, the cleavage of PP-derived chain hydrocarbons was promoted by the hydrogen abstraction reaction of lignin-derived oxygenates during co-pyrolysis. The hydrogen transfer reaction between hydrocarbons and phenols was enhanced, it was pushed for phenols to convert to aromatics. Thus, the yield of hydrocarbons in the range of jet fuel was improved. A new approach to the efficient application of lignin with PP might be offered by the current work. • Porosity and acidity of AC were altered by iron nitrate modification. • Co-pyrolysis products primarily hydrocarbons in the jet fuel range. • The selectivity of jet fuel range hydrocarbons was improved by AC modification. • Jet fuel range hydrocarbons were obtained with a carbon molar yield of 35.39%. [ABSTRACT FROM AUTHOR]

• MCM-41 catalyst is modified with different concentration of La. • Upgrading of pyrolysis vapor is performed in a vacuum system over above catalyst. • A higher hydrocarbons yield of 34.59% is obtained with La(5)/MCM-41. • Anti-coking performance of La(5)/MCM-41 for the coke is well. • It exhibited good potential for efficient preparation of high-valued bio-oil. By combining the large pore size of MCM-41 and the adjustable acid property of La, La/MCM-41 catalysts with La loading mass fractions of 1%, 5% and 10% were prepared and used in the catalytic upgrading of pyrolysis vapours from vacuum pyrolysis of rape straw to obtain high-value bio-oil. MCM-41 zeolite before and after the La loading was characterized in detail by TEM, Py-IR and TG. The characterization data showed that the amount of Brönsted and Lewis acid sites on the surface of La/MCM-41 increased. The highest hydrocarbon content (35%), and the highest higher heating value (34 MJ kg−1) were obtained at a La loading of 5% (La(5)/MCM-41). This may be closely related to the promotion of the reaction efficiency of the active sites with proper acid concentrations. Simultaneously, the coke content of the catalyst decreased further, and the selectivity for the high-value aromatic hydrocarbons increased. Considering the suitable concentration of La(5)/MCM-41 with strong acidity and stability, it is more appropriate for use in the upgrading of pyrolysis vapour for liquid fuel production. [ABSTRACT FROM AUTHOR]

A method of template removal by direct non-thermal plasma (DNTP) system for the synthesis of HZSM-5/MCM-41 meso-micropore composite catalyst was proposed for the production of aromatic hydrocarbons by catalytic pyrolysis of rape straw. It was revealed most of the template on the catalyst was removed by oxidizing substances such as ozone produced by DNTP. During DNTP treatment, the removal effect of the template was greatly affected by the oxygen flow rate. Also, the catalyst structure was bombarded by high-energy electrons obtained by DNTP treatment, and the physicochemical property of the synthetic composite catalysts was treated quite different from that obtained by calcination method. Under the treatment condition of 22 kV-2 L/min, the BET surface area was boosted significantly by 29.91% and the amount of acid sites was boosted by 37.71%, the yield of MAHs reached 10.57 wt%. Generally, not only the template can be effectively removed by DNTP treatment, but also the physicochemical property of meso-micropore composite catalyst can be improved, and thus promoted the catalytic performance for monocyclic aromatic hydrocarbons. Therefore, DNTP is an effective technology for removing template and the catalytic performance can be efficiently improved. • Template removal by DNTP system for synthesis of HZSM-5/MCM-41 catalyst. • Template was removed layer by layer from outside to inside. • Catalytic performance of catalyst was increased by DNTP treatment. • Removal effect of the template was greatly affected by oxygen flow rate. • Pore structure and BET surface area of catalyst were greatly affected by voltage. [ABSTRACT FROM AUTHOR]

• The concentration of active material of the DNTP reactor was controllable. • Carbon deposits will be removed and the catalyst perform better by DNTP reactor. • The pore size of regenerated catalysts increased due to electronic bombardment. • The regenerated catalyst at 22 kV performed best during catalytic pyrolysis. • High catalytic activity could be maintained after 15 cycles at 20 kV. A direct non-thermal plasma (DNTP) method was proposed to remove coke after catalytic pyrolysis of rape straw at atmospheric pressure and room temperature. Through the optical emission spectroscopy (OES) analysis, it was found that the active substances O 3 and O were generated inside the deactivated catalyst and reacted violently with the coke. After DNTP regeneration under different voltages of 20 kV, 22 kV, 24 kV, and 26 kV, the residual coke of each regenerated catalyst was almost completely removed, which were 2.65 %, 1.99 %, 1.29 %, and 0.30 %. Compared with fresh catalyst, the specific surface area of Cat-22 increased the most (34.09 %), and the total acid content increased by 24.11 %. The bio-oil obtained by Cat-22 had the highest monocyclic aromatic hydrocarbons content (46.93 %), which was 29.65 % higher than that of fresh catalyst. After fifteen cycles of catalysis-regeneration at 20 kV, it was found that the content of hydrocarbons of the bio-oil sample could be retained at 94.5 % of that in the original catalytic test. Through the DNTP technology based on the theoretical basis to realize the recycling of the catalyst, it will promote the development of biomass field in a more sustainable and cleaner way. [ABSTRACT FROM AUTHOR]

[Display omitted] • Catalytic fast pyrolysis of rape straw over composite catalysts was investigated. • HZSM-5@MCM-41 (H@M) was synthesized by external recrystallization method. • H@M with THR of 1 exhibited a highest yield of hydrocarbons of 11.43 wt.%. • H@M presented less formation of hydrogen-deficient or graphite-like coke. • Compared with HZSM-5, a lower pyrolysis temperature (500 °C) was demanded for H@M. In order to promote the production of hydrocarbons in the catalytic pyrolysis of rape straw, a core-shell catalyst fabricated by external recrystallization method was employed. The composite catalyst HZSM-5@MCM-41 was prepared by varying the mass ratio of template and HZSM-5 (THR), and the effect of zeolite acidity and mesoporosity on the production of hydrocarbons was analyzed. A final pyrolysis temperature of 500 °C was suitable to obtain high yield of hydrocarbons over composite catalysts. Compared with ZSM-5 with a favorable pyrolysis temperature of 550 °C, a lower pyrolysis temperature meant a more efficient process, which may be related closely to the good diffusion of large-sized pyrolysis vapors over HZSM-5@MCM-41 catalysts. In addition, the highest yield of monocyclic aromatic hydrocarbons obtained over HZSM-5@MCM-41 with THR of 1 was 11.43 wt.%, which was boosted by 2.5 times compared with HZSM-5. A proper THR was suitable to fabricate a core-shell catalyst with excellent crystallinity, acidity and mesoporosity, and resulting in a high yield of hydrocarbons. Furthermore, the core-shell catalyst presents less formation of graphite-like coke, which indicated the easier removal of coke. Therefore, the composite HZSM-5@MCM-41 catalysts were more appropriate for upgrading of pyrolysis vapors for hydrocarbons. [ABSTRACT FROM AUTHOR]

The main objective of the present work was applying a new method to regenerate the coked HZSM-5 zeolite on a laboratory scale. The non-thermal plasma injection (NTPI) technology, which can overcome the disadvantages of conventional regeneration methods, had been applied to regenerate HZSM-5 zeolite deactivated in the upgrading of biomass pyrolysis vapors. Experiments were carried out at different temperatures using self-designed setup to investigate the regeneration effect with O 2 as the discharge gas. The optimal regeneration temperature was around 250 °C and the regeneration process can be finished in a shorter time. Characterizations of the HZSM-5 zeolite before and after regeneration were profoundly performed by SEM, TG, BET method, Pyr-FT-IR and XRD. The coke can be removed completely and the activity of the coked HZSM-5 zeolite can be recovered quickly. The coke deposited on the HZSM-5 zeolite can be effectively decomposed into CO and CO 2 by reacting with the active substances which were generated through the discharge reactions of NTP generator. It is promising to apply this technology to the field of zeolite-based catalyst regeneration and realize its industrial applications in the near future. [ABSTRACT FROM AUTHOR]

Highlights: [•] A 2-in-1 process is proposed to directly catalyze the vacuum pyrolysis vapors. [•] Temperature, catalyst mass and Si/Al ratio affect the product yields significantly. [•] Oil phase yield is optimized by employing RSM and obtained at a higher value of 9.81%. [•] Oil phase has higher qualities with the HHV of 33.80MJ/kg and pH value of 5.15. [•] A large amount of aromatic hydrocarbons and light phenols are detected in oil phase. [ABSTRACT FROM AUTHOR]

Highlights: [•] Rape straw is a potential pyrolysis material for bio-oil preparation. [•] Effects on yield: heating rate>pyrolysis temperature>reactor pressure>holding time. [•] Heating rate and pyrolysis temperature have the interactive effects on bio-oil yield. [•] Polymerization contributes to the higher average molecular weight distribution. [•] Light aromatics are the dominant component contributing to the lower polydispersity. [Copyright &y& Elsevier]

Bio-aromatics preparation via in-situ catalytic pyrolysis of cellulose with lithium-ion battery ternary cathodes and ex-situ upgrading over Ru/HZSM-5 was studied. Three ternary cathodes with different ratios of Ni, Co, and Mn (NCM111, NCM532 and NCM811) were selected, and the effects of ternary cathodes and bifunctional Ru/HZSM-5 on the cellulose conversion were investigated from the perspectives of thermogravimetric kinetics and fixed-bed upgrading. The results indicated that cellulose pyrolyzed with cathodes reduced the solid residue content from 13.07% to 7.78%, 7.11%, and 6.63%, and decreased the weightlessness peak temperature from 358 ℃ to 348 ℃, 347 ℃, and 341 ℃; herein, the reaction order gradually elevated from 1.34 to 1.67 with the increased cathode Ni ratio, but the activation energy and pre-exponential factor obviously reduced. In-situ catalytic pyrolysis of ternary cathodes combined with ex-situ upgrading of Ru/HZSM-5 resulted in more cellulose-derived products being converted, increasing bio-oil yield from 22.47% to 25.08%, 24.75%, and 25.42%. Furfural was largely deoxygenated and dehydrated to become the precursor of aromatics, so NCM111, NCM532 and NCM811 usage increased the MAHs selectivity from 28.42% to 78.69%, 85.98%, and 87.27%, and high Ni ratio had higher deoxygenation capability and aromatic selectivity, simultaneously, it prone to creating material basis and spatiotemporal conditions for alkylation side reaction to increase C9 and above hydrocarbons. However, 1H NMR analysis confirmed that the main reaction of aromatization was still stronger than the side reaction even under high Ni ratio condition. Aromatics and coke production from acidic zeolite catalyzed reforming of oxygenates were competing reactions. In-situ catalysis of ternary cathodes produced more small molecule products to enter the inner pores of Ru/HZSM-5, forming more difficult to remove microporous coke, and the effect of increased Ni ratio was more obvious, but coke content reduced from 4.51% to 4.11%, 4.13%, and 3.05%, respectively. • Cellulose to aromatics was studied by in-situ catalytic pyrolysis and ex-situ upgrade. • Ternary cathode with high Ni ratio was beneficial for regulating kinetic parameters. • MAHs production was elevated, and high Ni cathode had higher aromatic selectivity. • Alkylation reaction under high Ni ratio increased C9 and above aromatic hydrocarbons. • Ternary cathodes contributed to more microporous coke, and high Ni ratio reduced coke. [ABSTRACT FROM AUTHOR]

Coke deposition in the catalytic fast pyrolysis of biomass includes active coke and inert coke, which promote or inhibit the formation of hydrocarbons. This study aims at the evolution of coke formation on various catalysts in the catalytic conversion of furan as an important intermediate from biomass fast pyrolysis. The functional groups on the surface of each catalyst at every moment were recorded by in situ diffuse reflectance Fourier transform infrared spectroscopy. The results indicated that the coke formation was closely related to the structure and acid property of the catalysts combined with catalytic tests in a fixed-bed reactor. Though dealumination only changed the acid distribution, it increased the hydrocarbon yield and introduced different chemical component of active coke. Because MCM-22 had a large internal space and small windows, its coke content should be quite large. However, the coke on MCM-22 did not show large molecules in this study because of the wide acid distribution, and similar active coke species with ZSM-5 were detected of polymethyl benzaldehyde. The coke content of HY was small because of large quantities of weak acid, although HY showed a significantly large internal space. The main components of active coke on HY and Hβ were diolefinic alcohols and polymethyl benzenes. The understanding of coke formation on various catalysts will provide guidelines for catalyst design, i.e., it is suggested that 3-dimensional structures such as MCM-22 with large supercages and small windows can be introduced into the original ZSM-5 system to form a core-shell catalyst to increase the hydrocarbon yields. [ABSTRACT FROM AUTHOR]