Abstract:Catalytic fast pyrolysis of pine sawdust was successfully carried out in VTT's 20 kg h −1 Process Development Unit using a spray dried HZSM-5 catalyst. Approximately 250 kg of partially deoxygenated pyrolysis oil was produced over a period of four days. The catalytically produced pyrolysis oil had an average moisture content of 8.3 wt%, and average carbon and oxygen contents of 72.0 and 21.5 wt% on a dry basis, respectively. Approximately 24% of the original biomass carbon was present in the pyrolysis oil, whe… Show more
“…Approximately 4 mg of the mixtures were then fast pyrolyzed in the pyroprobe reactor at 550 C for 60 s. Note that due to the small sample size that can be placed in CDS pyroprobe, high catalyst-to-reactant ratios (e.g., [10][11][12][13][14][15][16][17][18][19][20] are required to ensure effective conversion of biomass-and plastic-derived volatile intermediates (e.g., acids and aldehydes) to desired nal products (i.e., aromatic and olen hydrocarbons) within the zeolite framework. 44,45 The volatiles emitted via the fast heating were carried by helium through a heated transporting tube (300 C) to a gas chromatograph (Agilent 7890A GC). 44,45 The volatiles emitted via the fast heating were carried by helium through a heated transporting tube (300 C) to a gas chromatograph (Agilent 7890A GC).…”
A series of phosphorus (P) and phosphorus/nickel (P/Ni) modified ZSM-5 zeolites were prepared by impregnation of a conventional ZSM-5 zeolite with P and subsequent Ni. The conventional, P-, and P/Ni-modified ZSM-5 zeolites were then tested as the catalysts for petrochemical production from cofeed catalytic fast pyrolysis (CFP) of pine wood and low-density polyethylene (LDPE) mixtures. Results showed that the yield of valuable petrochemicals (olefins and aromatic hydrocarbons) from co-feed CFP increased from 42.9 C% for conventional ZSM-5 to 52.8-54.1 C% for P-and P/Ni-modified ZSM-5, while the yields of low-value alkanes and undesired char/coke decreased from 17.3 C% and 22.6 C% to 9.6-10.2 C% and 18.9-15.7 C%, respectively. ZSM-5 impregnation with P and P/Ni thus significantly improved the product distribution in co-feed CFP of biomass and LDPE. In addition, modification with P and P/Ni improved considerably the hydrothermal stability of zeolites to resist steam-induced catalyst deactivation that may occur in co-feed CFP. When the conventional ZSM-5 zeolite was pretreated with 100% steam at 550 C for 3-9 h, it produced 26.7-32.1% lower aromatic yields than untreated ZSM-5 in co-feed CFP. In contrast, steam pretreatment did not considerably affect the activity of P-and P/Ni-ZSM-5 zeolites for aromatic production. They maintained comparable aromatic yields in co-feed CFP when they had been steam pretreated for up to 9 h. These results indicate that ZSM-5 modification with P and P/Ni may provide a viable way to improve the catalyst's activity and life time for petrochemical production from co-feed CFP of biomass and plastics.
“…Approximately 4 mg of the mixtures were then fast pyrolyzed in the pyroprobe reactor at 550 C for 60 s. Note that due to the small sample size that can be placed in CDS pyroprobe, high catalyst-to-reactant ratios (e.g., [10][11][12][13][14][15][16][17][18][19][20] are required to ensure effective conversion of biomass-and plastic-derived volatile intermediates (e.g., acids and aldehydes) to desired nal products (i.e., aromatic and olen hydrocarbons) within the zeolite framework. 44,45 The volatiles emitted via the fast heating were carried by helium through a heated transporting tube (300 C) to a gas chromatograph (Agilent 7890A GC). 44,45 The volatiles emitted via the fast heating were carried by helium through a heated transporting tube (300 C) to a gas chromatograph (Agilent 7890A GC).…”
A series of phosphorus (P) and phosphorus/nickel (P/Ni) modified ZSM-5 zeolites were prepared by impregnation of a conventional ZSM-5 zeolite with P and subsequent Ni. The conventional, P-, and P/Ni-modified ZSM-5 zeolites were then tested as the catalysts for petrochemical production from cofeed catalytic fast pyrolysis (CFP) of pine wood and low-density polyethylene (LDPE) mixtures. Results showed that the yield of valuable petrochemicals (olefins and aromatic hydrocarbons) from co-feed CFP increased from 42.9 C% for conventional ZSM-5 to 52.8-54.1 C% for P-and P/Ni-modified ZSM-5, while the yields of low-value alkanes and undesired char/coke decreased from 17.3 C% and 22.6 C% to 9.6-10.2 C% and 18.9-15.7 C%, respectively. ZSM-5 impregnation with P and P/Ni thus significantly improved the product distribution in co-feed CFP of biomass and LDPE. In addition, modification with P and P/Ni improved considerably the hydrothermal stability of zeolites to resist steam-induced catalyst deactivation that may occur in co-feed CFP. When the conventional ZSM-5 zeolite was pretreated with 100% steam at 550 C for 3-9 h, it produced 26.7-32.1% lower aromatic yields than untreated ZSM-5 in co-feed CFP. In contrast, steam pretreatment did not considerably affect the activity of P-and P/Ni-ZSM-5 zeolites for aromatic production. They maintained comparable aromatic yields in co-feed CFP when they had been steam pretreated for up to 9 h. These results indicate that ZSM-5 modification with P and P/Ni may provide a viable way to improve the catalyst's activity and life time for petrochemical production from co-feed CFP of biomass and plastics.
“…Also, perhaps most significantly, zeolite catalysts can be irreversibly fouled by alkali and alkaline earth metals present in biomass feedstocks. This fouling leads to loss of acidity and activity of the catalyst (Mullen and Boateng, 2013;Paasikallio et al, 2014).…”
The present study examines the effect of calcium pretreatment on pyrolysis of individual lignocellulosic compounds. Previous work has demonstrated that the incorporation of calcium compounds with the feedstock prior to pyrolysis has a significant effect on the oxygen content and stability of the resulting oil. The aim of this work was to further explore the chemistry of calcium-catalyzed pyrolysis. Bench-scale pyrolysis of biomass constituents, including lignin, cellulose and xylan is performed and compared to the oils produced from pyrolysis of the same components after calcium pretreatment. The resulting oils were analyzed by quantitative GC-MS and SEC. These analyses, together with data collected from previous work provide evidence which was used to develop proposed reaction pathways for pyrolysis of calcium-pretreatment biomass.
“…Although CFB reactors are effective in dealing with coke, the inorganics present in the pyrolysis feedstock present an additional challenge that is yet to be addressed . It has been shown previously that biomass‐derived metals deposit on the catalyst during in situ CFP, and this deposition has been correlated with, for example, a decrease in catalyst acidity and the extent of bio‐oil deoxygenation . Various approaches to address this challenging issue are discussed in a recent review by Yildiz et al …”
Section: Introductionmentioning
confidence: 99%
“…Although the main product of interest from CFP is bio‐oil, increased water production because of acid‐catalyzed dehydration reactions results in the formation of a separate aqueous‐phase product. The water‐soluble organics in this aqueous fraction can represent a significant portion of the overall CFP product slate . The majority of these water‐soluble organic molecules fall into compound classes that can be converted into value‐added products using HZSM‐5 catalysts .…”
In situ catalytic fast pyrolysis can be used to produce partially upgraded bio‐oils. This process, however, suffers from rapid catalyst deactivation caused by coke formation, which necessitates the use of continuous catalyst regeneration. This can be achieved by using a circulating fluidized‐bed reactor. In such a reactor, one key operational variable is the catalyst‐to‐biomass (C/B) ratio, which influences the extent of the catalytic reactions that take place. In this study, woody biomass is pyrolyzed in a pilot‐scale circulating fluidized‐bed reactor system using a HZSM‐5 zeolite with varying C/B ratios. The C/B ratio influences the overall product distribution, the elemental distribution, and the characteristics of the liquid products. An increase of the C/B ratio enhances the conversion of pyrolysis vapors but this does not result in a continuous improvement in bio‐oil quality. The C/B ratio is, nevertheless, a factor that can be used to optimize the catalytic fast pyrolysis process.
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