Suppression of coke formation and enhancement of aromatic hydrocarbon production in catalytic fast pyrolysis of cellulose over different zeolites: effects of pore structure and acidity

RSC Advances ◽  
2015 ◽  
Vol 5 (80) ◽  
pp. 65408-65414 ◽  
Author(s):  
Pouya Sirous Rezaei ◽  
Hoda Shafaghat ◽  
Wan Mohd Ashri Wan Daud
Keyword(s):  
Catalytic Pyrolysis ◽  
Pore Space ◽  
Coke Formation ◽  
Fast Pyrolysis ◽  
Acid Sites ◽  
Low Density ◽  
Hydrocarbon Production ◽  
Biomass Feedstocks ◽  
Pyrolysis Of Biomass ◽  
Internal Pore

In catalytic pyrolysis of biomass feedstocks over zeolites, larger catalyst pores result in lower thermal coke. Besides, catalytic coke formation is suppressed by a small internal pore space or low density of acid sites.

scholarly journals Microwave-Assisted Catalytic Fast Pyrolysis of Biomass for Hydrocarbon Production with Physically Mixed MCM-41 and ZSM-5

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 685
Author(s):  
Zeyu Xue ◽  
Zhaoping Zhong ◽  
Bo Zhang
Keyword(s):  
Coke Formation ◽  
Fast Pyrolysis ◽  
Mass Ratio ◽  
Corn Straw ◽  
Hydrocarbon Production ◽  
Catalytic Fast Pyrolysis ◽  
Microwave Assisted ◽  
Hydrocarbon Formation ◽  
Pyrolysis Of Biomass ◽  
Mcm 41

To delve into the law of hydrocarbon production in microwave-assisted catalytic fast pyrolysis (MACFP) of corn straw, physical mixed Mesoporous Crystalline Material-41 (MCM-41) and Zeolite Socony Mobile-5 (ZSM-5) catalyst prototypes were exploited in this study. Besides, the effects exerted by temperature of reaction and MCM-41/ZSM-5 mass ratio were explored. As revealed from the results, carbon outputs of hydrocarbons rose initially as the temperature of MACFP rose and reached the maximal data at 550 °C; subsequently, it declined as reaction temperature rose. Moreover, the MCM-41/ZSM-5 mass ratio of 1:2 was second-to-none for hydrocarbon formation in the course of biomass MACFP. It was reported that adding MCM-41 can hinder coke formation on ZSM-5. Furthermore, MCM-41/ZSM-5 mixture exhibited more significant catalytic activity than ZSM-5/MCM-41 composite, demonstrating that hydrocarbon producing process can be stimulated by a simple physical MCM-41 and ZSM-5 catalysts mixture instead of synthesizing complex hierarchically-structured ZSM-5/MCM-41 composite.

Analysis of Precursors of Carbon Deposition in Hydrogen Preparation by Fast Pyrolysis of Bio-Oil via Catalytic Steam Reforming

2012 ◽  
Vol 512-515 ◽  
pp. 338-342 ◽  
Author(s):  
Ping Lan ◽  
Li Hong Lan ◽  
Tao Xie ◽  
An Ping Liao
Keyword(s):  
Steam Reforming ◽  
Molecular Sieve ◽  
Carbon Deposition ◽  
Catalyst Activity ◽  
Coke Formation ◽  
Fast Pyrolysis ◽  
Bio Oil ◽  
Aldehydes And Ketones ◽  
Pyrolysis Of Biomass ◽  
Catalytic Steam Reforming

In the preparation of hydrogen, the bio-oil from pyrolysis of biomass must be further upgraded (catalytic steam reforming)SO as to improve its quality．However the catalyst used in the steam reforming reaction is easy to lose its activity due to being coked' SO that it is important to study the coke formation and its efects on the catalyst activity in the steam reforming process．Fourier Transform Infrared Spectroscopy were used to analyze the precursor of coke on the catalyst Ni/MgO-La2O3-Al2O3 used in steam reforming reaction and the mechanism of coking Was also discussed based on it．The results indicate that precursors of coke deposited inside the pore of the molecular sieve are mainly paraffin, alcohols, aldehydes and ketones, and aromatic compounds.

scholarly journals Catalytic pyrolysis of hemicellulose to produce aromatic hydrocarbons

BioResources ◽  
2019 ◽  
Vol 14 (3) ◽  
pp. 5816-5831
Author(s):  
Yi Yang ◽  
Zhongyang Luo ◽  
Simin Li ◽  
Kongyu Lu ◽  
Wenbo Wang
Keyword(s):  
Gas Chromatography ◽  
Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbons ◽  
Catalytic Pyrolysis ◽  
Shape Selectivity ◽  
Acid Sites ◽  
Zeolite Catalysts ◽  
Hydrocarbon Production ◽  
Monocyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic

Catalytic fast pyrolysis of hemicellulose with zeolite catalysts is a promising method to produce aromatic hydrocarbons (Carlson et al. 2009). In this paper, the behavior of hemicellulose catalytic pyrolysis with HZSM-5 (with three different silica to alumina ratio, 23, 50, 80), HY, and Hβ was studied. Pyrolysis vapor was separated into non-condensable vapors and condensable fractions. The fractions were qualified and quantified by a gas chromatography / flame ionization detector (GC/FID) system and a gas chromatography / mass spectrometer (GC/MS) system, respectively. The influences of catalysts and pyrolysis parameters were studied. Among the catalysts, HZSM-5(23) provided the desired acidity and shape selectivity for aromatic hydrocarbon production. A higher catalyst to hemicellulose ratio (CHR) and higher heating rate resulted in a higher aromatic hydrocarbon yield. The most suitable pyrolysis temperature for hemicellulose with HZSM-5 was 650 °C. During catalytic pyrolysis, thermal decomposition products underwent deoxygenation reactions promoted by the acid sites on the zeolite. The C2-C4 deoxygenated products produced monocyclic aromatic hydrocarbons (MAH) by shape-selective catalysis reactions in zeolite pores. With higher temperatures and higher residence times, monocyclic aromatic hydrocarbons facilitated cyclization reactions with C2-C4 deoxygenated products, thereby forming polycyclic aromatic hydrocarbons (PAH).

Selective production of aromatic hydrocarbons from catalytic pyrolysis of biomass over Cu or Fe loaded mesoporous rod-like alumina

RSC Advances ◽  
2016 ◽  
Vol 6 (56) ◽  
pp. 50618-50629 ◽  
Author(s):  
Surachai Karnjanakom ◽  
Asep Bayu ◽  
Pairuzha Xiaoketi ◽  
Xiaogang Hao ◽  
Suwadee Kongparakul ◽  
...  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Catalytic Pyrolysis ◽  
Fast Pyrolysis ◽  
Bio Oil ◽  
Sunflower Stalks ◽  
Pyrolysis Of Biomass ◽  
Alumina Catalysts

The selective production of aromatic hydrocarbons from bio-oil derived from the fast pyrolysis of sunflower stalks over Cu or Fe-modified mesoporous rod-like alumina catalysts was investigated.

Aromatic hydrocarbon production by catalytic pyrolysis of palm kernel shell waste using a bifunctional Fe/HBeta catalyst: effect of lignin-derived phenolics on zeolite deactivation

2016 ◽  
Vol 18 (6) ◽  
pp. 1684-1693 ◽  
Author(s):  
Pouya Sirous Rezaei ◽  
Hoda Shafaghat ◽  
Wan Mohd Ashri Wan Daud
Keyword(s):  
Catalytic Pyrolysis ◽  
Lignin Content ◽  
Palm Kernel ◽  
Acid Sites ◽  
Hydrocarbon Production ◽  
Palm Kernel Shell ◽  
Shell Waste ◽  
Biomass Materials ◽  
Catalyst Effect ◽  
High Lignin Content

Lignin-derived phenolics are tightly bound with zeolite acid sites, and act as coke precursors. A bifunctional Fe/HBeta catalyst is efficient for upgrading of biomass materials with high lignin content.

An analytical microscopic study of metals in fluidized catalytic cracking catalyst

1986 ◽  
Vol 44 ◽  
pp. 854-855
Author(s):  
Clifford S. Rainey
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Acid Sites ◽  
Y Zeolite ◽  
Fcc Catalyst ◽  
Fluidized Catalytic Cracking ◽  
High Regeneration

The spatial distribution of V and Ni deposited within fluidized catalytic cracking (FCC) catalyst is studied because these metals contribute to catalyst deactivation. Y zeolite in FCC microspheres are high SiO2 aluminosilicates with molecular-sized channels that contain a mixture of lanthanoids. They must withstand high regeneration temperatures and retain acid sites needed for cracking of hydrocarbons, a process essential for efficient gasoline production. Zeolite in combination with V to form vanadates, or less diffusion in the channels due to coke formation, may deactivate catalyst. Other factors such as metal "skins", microsphere sintering, and attrition may also be involved. SEM of FCC fracture surfaces, AEM of Y zeolite, and electron microscopy of this work are developed to better understand and minimize catalyst deactivation.

scholarly journals Insight into Active Centers and Anti-Coke Behavior of Niobium-Containing SBA-15 for Glycerol Dehydration

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 488
Author(s):  
Katarzyna Stawicka ◽  
Maciej Trejda ◽  
Maria Ziolek
Keyword(s):  
Coke Formation ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Silica Matrix ◽  
High Concentration ◽  
Active Centers ◽  
Acidic Sites ◽  
Glycerol Dehydration ◽  
Adsorption Desorption ◽  
Insight Into

Niobium containing SBA-15 was prepared by two methods: impregnation with different amounts of ammonium niobate(V) oxalate (Nb-15/SBA-15 and Nb-25/SBA-15 containing 15 wt.% and 25 wt.% of Nb, respectively) and mixing of mesoporous silica with Nb2O5 followed by heating at 500 °C (Nb2O5/SBA-15). The use of these two procedures allowed obtaining materials with different textural/surface properties determined by N2 adsorption/desorption isotherms, XRD, UV-Vis, pyridine, and NO adsorption combined with FTIR spectroscopy. Nb2O5/SBA-15 contained exclusively crystalline Nb2O5 on the SBA-15 surface, whereas the materials prepared by impregnation had both metal oxide and niobium incorporated into the silica matrix. The niobium species localized in silica framework generated Brønsted (BAS) and Lewis (LAS) acid sites. The inclusion of niobium into SBA-15 skeleton was crucial for the achievement of high catalytic performance. The strongest BAS were on Nb-25/SBA-15, whereas the highest concentration of BAS and LAS was on Nb-15/SBA-15 surface. Nb2O5/SBA-15 material possessed only weak LAS and BAS. The presence of the strongest BAS (Nb-25/SBA-15) resulted in the highest dehydration activity, whereas a high concentration of BAS was unfavorable. Silylation of niobium catalysts prepared by impregnation reduced the number of acidic sites and significantly increased acrolein yield and selectivity (from ca. 43% selectivity for Nb-25/SBA-15 to ca. 61% for silylated sample). This was accompanied by a considerable decrease in coke formation (from 47% selectivity for Nb-25/SBA-15 to 27% for silylated material).

scholarly journals Influence of the Zeolite ZSM-5 on Catalytic Pyrolysis of Biomass via TG-FTIR

BioResources ◽  
2015 ◽  
Vol 10 (3) ◽  
Author(s):  
Ze Wang ◽  
Siwei Liu ◽  
Weigang Lin ◽  
Wenli Song
Keyword(s):  
Catalytic Pyrolysis ◽  
Pyrolysis Of Biomass
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