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Production of lighter hydrocarbons by steam-assisted catalytic cracking of heavy oil over silane treated Beta zeolite Umer Khalil, Oki Muraza, Hisaki Kondoh, Gaku Watanabe, Yuta Nakasaka, Adnan M. Al-Amer, and Takao Masuda Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.5b02525 • Publication Date (Web): 15 Jan 2016 Downloaded from http://pubs.acs.org on January 19, 2016
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Production of lighter hydrocarbons by steam-assisted catalytic cracking of heavy oil over silane treated Beta zeolite Umer Khalila, Oki Muraza*a, Hisaki Kondohb, Gaku Watanabeb, Yuta Nakasakab, Adnan AlAmera, Takao Masudab a
b
Center of Excellence in Nanotechnology & Chemical Engineering Department, King Fahd University of Petroleum and Minerals, Saudi Arabia.
Division of Chemical Process Engineering, Faculty of Engineering, Hokkaido University, N13 W8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan Email:
[email protected] Abstract The surface of Beta zeolite (SiO2/Al2O3=150) was modified using triphenyl silane in a liquid phase and a series of catalysts was applied in cracking of heavy oil in the presence of steam. Steam reduces the coke formation, but at the same time zeolite catalysts may be degraded in an aqueous environment at high temperature. This problem was overcome by using the surfacemodified zeolite catalyst. The silane treatment of zeolite surface not only reduced the coke amount but also stabilized the catalyst by increasing the hydrophobicity of the external surface of the zeolite. Moreover, atmospheric residue, which was used as a heavy oil feedstock, effectively decomposed into lighter hydrocarbon (gasoline, kerosene, and gas oil) over silane treated Beta zeolite. Different reaction times were evaluated for modified Beta zeolite in steam-assisted catalytic cracking of atmospheric residue. The yield of the lighter hydrocarbon (C7-C35) was increased significantly up to 50.4 mol% in the product stream over silane treated catalysts after 2 h reaction time, while the gasoline production was increased to 35.4 mol% as compared to 30.9 mol% over a parent Beta catalyst. This indicates an improvement on the stability of Beta catalysts after silane treatment. Keywords: Hydrophobic zeolites; heavy oil; silanes; Beta zeolite. 1 ACS Paragon Plus Environment
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1. Introduction In a world striving for an increased production of lighter fuels, it is important to find effective techniques for the upgrading of heavy oil. Among the many techniques, hydrous pyrolysis, also known as aquathermolysis has gained more attentions 1. Nowadays, different catalysts have extensively studied in aquathermolysis process and it was found that catalysts improved the process efficiency remarkably
2-4
. Recently, a performance of catalysts such as metal
nanoparticles and solid acid oxides have been studied in cracking reactions
3-9
. Metal oxide
catalysts, which are already used in the presence of steam showed the good conversion of heavy oil as steam favors the formation of the active sites on metal oxides
10, 11
. Zeolites have shown
promising results when employed for the cracking of n-hexane in the presence of steam 12. Steam reduces the amount of coke and increases the production of olefins. Heavy oil cracking in aqueous environment demands more stable zeolite catalysts as coke formation and dealumination are more severe in these conditions. Previously, phosphorus and lanthanum incorporated zeolites demonstrated improved stability in an aqueous environment at elevated temperature
13, 14
.
Extraction of aluminum (Al) from the zeolite framework improves hydrophobicity but also causes loss of active sites for cracking reaction. Previously, organosilane treatment of zeolites have been reported by different groups showing different results; for instance, Serrano et al studied in-situ organosilane treatment to obtain hierarchical ZSM-5
15
, while Zapata et al used organo silane compounds to fabricate
hydrophobic UY zeolite 16 and Tago et al controlled the activity of ZSM-5 by creating SiO2 units on the external zeolite surface 17. Organosilane treatment of the external surface of zeolites is an effective route to improving hydrophobicity. Silane groups, with larger kinetic diameter than the zeolite pore, attach to the external surface and prevent the attack of water molecules. 2 ACS Paragon Plus Environment
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Modification of zeolite Y with organosilane compounds of different chain lengths showed improved hydrophobicity in biofuel upgrading reactions
16
. Highly active zeolite catalysts for
cracking reactions also encounter coking problems. Hydrophibic silane treated zeolite catalysts may overcome problems associated with coking and degradation in the presence of steam. In this work, effects of silane treated Beta (BEA) zeolite on the steam-assisted cracking of atmospheric residue (AR) were investigated. Pore system and high acidity of BEA zeolite have numerous industrial applications in cracking isomerization and alkylation reactions. BEA zeolite, considered as a large port three-dimensional 12-ring framework structure with a pore opening of 0.67 nm, was modified using triphenyl silane through liquid phase deposition method. An increase in the production of lighter hydrocarbons was targeted using steam and modified BEA zeolite. Steam assisted cracking of heavy oil over hydrophobic zeolite decreases the coke formation and increase the stability, which may result in a higher yield of lighter hydrocarbon. Stability of modified and parent BEA zeolite catalysts was studied for different reaction times; after 2 h and 4 h. Degradation of zeolites in the aqueous environment was mitigated using silane modified zeolites. 2. Experimental 2.1 Silane treatment of zeolite catalyst High silica Beta (BEA) zeolite catalyst (SiO2/Al2O3=150, provided by Catalysis Society of Japan) was used as the starting material. As received BEA was first ion-exchanged, 20 g of 2 M ammonium nitrate (NH4 (NO3)) solution was used for each gram of zeolite. The mixture was heated under continuous stirring for 3 h. The final solution was centrifuged to recover zeolite from solution. Zeolite was washed with distilled water several times. The same procedure was
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repeated sequentially thrice. The NH4+-BEA zeolite was dried at 373 K for 12 h. Powder sample was first pelletized to get ca. 0.3 mm in diameter pellets and then calcined at 823 K for 3h in an air stream. Protonated BEA obtained after calcination was used as a BEA-parent catalyst in cracking reactions. For silane treatment, H-BEA in powder form was used. After silane treatment, zeolite sample was pelletized and used in cracking reaction. The H-BEA zeolite was modified in the liquid phase using adapted procedure previously proposed by Zapata et al 18. As a typical run 1 g of zeolite was dispersed in 20 ml of toluene and sonicated for 20 min at room temperature. Triphenyl silane (0.5 mmol/g zeolite) was added in zeolite/toluene mixture and stirred for 24 h at room temperature. Finally, zeolite was collected by filtration and washed several times with ethanol. Modified zeolite was then dried at 373 K overnight. The modified catalyst was used as BEA silane treated catalyst in steam-assisted heavy oil cracking reaction.
2.2 Characterization of catalysts Structure and phase purity of all BEA catalysts were confirmed by X-ray diffractometer (Ultima IV, Rigaku). Surface areas of catalysts were calculated by BET-method using N2 adsorption isotherms (Belsorp mini, BEL JAPAN). The acidity of catalysts was evaluated using the NH3TPD method. Typically, 1.0% NH3 (balance He) was used as carrier gas at the heating rate of 5 K min-1 and temperature range was 373-823 K. NH3 molecules were desorbed from acid sites of zeolite under complete adsorption equilibrium conditions (1.0% NH3-He atmosphere)
19
.
Thermogravimetric analysis (TGA) was used to measure the amount of coke for all samples.
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2.3 Steam assisted catalytic cracking of heavy oil Catalytic cracking of atmospheric residue (AR) in the presence of steam was carried out in fixedbed type reactor at 743 K and a pressure of 1 atm for 2 and 4 h. Fig. 1 shows the schematic setup of fixed-bed reactor used in this work. Heavy oil was diluted with toluene at 10 wt.% to reduce the viscosity. Nitrogen (5 mL/min), steam (5 mL/min) and feed mixture (2.9 mL/h) were fed to the reactor simultaneously. The W/F (weight of catalyst/feed flow rate) was 4 h, where W was the weight of catalyst (g), F was the feed flow rate (g.h-1). FH2O/F was 2 where FH2O was the flow rate of water (g.h-1). The water was pumped using a syringe pump and converted into superheated steam at 433 K. These reaction parameters were optimized previously to obtain the highest conversion. The liquid products were collected through a condenser and the gas products were tapped using a gas bag. The products were analyzed using a gas chromatography, which was equipped with a thermal conductivity detector (TCD; model GC-8A, Shimadzu, Ltd), a flame ionization detector (FID; model GC-12A, Shimadzu, Ltd), activated carbon and Porapak-Q columns, respectively. The liquid products were analyzed using high-performance liquid chromatograph (model: CTO-10A, Shimadzu, Ltd). The products with carbon number less than six (such as C4 and C5) were not listed in product analysis. The toluene, which was detected in the liquid product was also excluded from the calculation of the yield. The error in mass balance using liquid chromatoghraphy was kept minimum below 5% 10, 11, 20. Please insert Figure 1 here.
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3. Results and discussion 3.1 Effect of silane treatment on catalysts properties Liquid phase deposition of silane compound on BEA zeolite (SiO2/Al2O3 = 150) was adapted following a procedure reported earlier by Zapata et al
18
. Triphenyl silane as a reagent was
selected on the basis of its kinetic diameter, which should be larger than the pore size of BEA. Fig. 2 shows the XRD patterns of parent BEA and liquid phase silane treated BEA zeolites. No change in the purity of phase was observed while a very less change in crystallinity was noted as expected after the surface modification of zeolite. N2 adsorption isotherms in Fig. 3 show that the adsorption properties of both parent and silane treated catalysts are approximately same. Table 1 presents the change in detailed texture properties after modification, which again shows the increase in external surface area, attributes that organosilane compounds attached to the external surface of BEA catalysts and did not enter into the pore of BEA zeolite. These findings were important because the inner acidity of zeolite remained unaltered and available for cracking reactions. Fig. 4 shows the NH3-TPD profiles of parent and silane treated zeolites. A decrease in both weak and strong acid sites was observed. NH3 desorption peak at a temperature above 600 K associated with strong acid sites showed a decreasing trend after modification. Silane compounds attached to both weak and strong sites, which were located at the outer surface of Beta zeolite. A large number of acid sites increases the activity of the catalyst and provides more sites for cracking reaction. However, it was also found that the coke formation linearly increases with an activity of the catalyst. Hence, silane groups attached to the selective acid sites also controls coke formation 21, 22.
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Please insert Fig. 2 here. Please insert Fig. 3 here. Please insert Fig. 4 here.
3.2 Effect of surface modified catalyst on steam-assisted cracking of AR Surface modified BEA zeolite was applied in heavy oil cracking reaction for 2 h and 4 h reaction time. The products were classified according to their carbon number into six groups: gases, gasoline + kerosene (C7-C13), gas oil (C14-C20, C21-C35), and heavy oil (C36-C44, above C45). To investigate the effect of surface modification on the cracking of atmospheric residue oil, silane treated catalyst was evaluated for 2 h reaction time and liquid as well as gas product distribution was analyzed. Steam plays an important role in the cracking reactions over zeolite catalysts as it helps to decrease the amount of coke formation, but at the same time dealumination of the zeolite catalyst in the presence of steam is a major problem 12, 13, 23. Reducing the rate of dealumination using silane-treated zeolite tends to increase conversion of heavy feedstock into a lighter hydrocarbon. This assumption is verified in Fig. 5 which represents the increase in gasoline (C7C13) yield over silane treated BEA zeolite catalyst as compared to the parent BEA catalyst. Also, the yield of lighter hydrocarbon products (C7-C35) increased up to 50.3 mol%. These results indicate that silane treated BEA catalyst retained its activity after 2 h reaction time. Moreover, a decrease in coke formation over the silane treated BEA catalyst was also observed. It is worth mentioning that C35+ yield over modified catalyst was negligible as compared to the one for parent catalyst. Gas composition analysis after 2 h reaction time in Fig. 6 shows no hydrogen formed in both parent and modified BEA catalysts. While it was reported that considerable 7 ACS Paragon Plus Environment
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amount of hydrogen was produced over metal oxide catalysts, which indicates the formation of coke
5, 10, 11, 20
. Problems involving dealumination caused in the presence of steam and coke
formation were mitigated using silane-treated zeolite catalysts. Major constituents of the gases produced were alkenes and alkanes in the case of BEA-zeolite. Please insert Fig. 5 here. Please insert Fig. 6 here. Molecular weight distribution curves in Fig. 7 showed full agreement with above-mentioned results. Curves in Fig. 7 indicates the molecular weight distribution of hydrocarbons. Hence, the highest peak in the lower molecular weight region shows that liquid product contains higher percentage of low molecular weight hydrocarbons over silane treated catalysts. The higher amount of the lighter hydrocarbon over silane treated catalysts showed less coke formation. Fig. 8 shows the physical appearance of liquid product after reaction over parent and the modified BEA zeolite catalyst. The apparent color of liquid product has changed from dark yellow over BEA-parent to light yellow over BEA-Silane treated. Lighter liquid hydrocarbon (C7-C35) composition (mol%) was increased from 46.29 mol % to 50.44 mol%. This increase is not significant enough to affect the color of the liquid product. Moreover, the amount of gases produced were higher over BEA-silane treated catalyst.
Please insert Fig. 7 here. Please insert Fig. 8 here. 3.3 Effect of reaction time on the catalysts stability Stability of parent and silane treated BEA catalyst was measured after a prolonged reaction time for 4 h. Reaction test was repeated for 4 h over parent and silane treated catalyst and product distribution was carefully studied. Fig. 9 represents an increase in lighter component yield over
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silane treated BEA-zeolite catalyst. Gasoline (C7-C13) yield increased up to 34.1 mol% as compared to 27 mol% over parent BEA-zeolite. Relatively less amount of coke formed over silane treated BEA catalyst showed partial coverage of the external sites by silane compounds. Less amount of coke leads to the improved stability of catalyst and higher yield of lighter components. Gas composition analysis in Fig. 10, which is presented mol/g-AR of products, shows a higher amount of hydrogen gas produced over the parent BEA catalyst after 4 h reaction, which indicates that after longer reaction time, a significant amount of coke was deposited on the parent BEA catalyst while there was no hydrogen gas was formed over silane treated BEA catalyst, even after 4 h reaction time. Major gas constituents in the gas of silane treated zeolite were alkanes and alkenes. A high percentage of alkenes was obtained over silane treated zeolite. Fig. 11 represents the liquid product distribution according to their molecular weight. Large area under the graph of silane treated zeolite in the low molecular weight region showed a high percentage of lighter components. Please insert Fig. 9 here. Please insert Fig. 10 here. Please insert Fig. 11 here.
Change in the crystallinity of parent and modified catalysts was studied from XRD patterns. Fig. 12 (XRD patterns) shows that the BEA catalyst retained its crystallinity, even after 2 h reaction and phase purity was still intact. Despite no structural changes were observed after 2 h for parent BEA catalyst, some changes in phase purity were clearly observed after the 4h reaction. Impure phase was appeared after a longer reaction time in parent catalyst, which indicates changes in the 9 ACS Paragon Plus Environment
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structure of the zeolite. On the other hand, the silane treated BEA-catalyst exhibited stable structure even after 4 h. Silane compounds attached to the external surface of zeolite prevented the structure from the attack of water and made stable hydrophobic catalyst. The
27
Al NMR
spectra of BEA-silane treated catalyst after 4 h reaction time in Fig. 13 shows the only signal centered at about δ = 56 ppm corresponding to tetrahedral coordination of aluminum, while there is no extra framework aluminium (EFAL) at δ = 0 ppm, which suggests that no dealumination during the course of the reaction. In contrast, a peak is found at δ = 0 ppm in the case of spent BEA-parent catalyst, which suggests the formation of EFAL in the aqueous environment. Please insert Fig. 12 here. Please insert Fig. 13 here.
Conclusions It was found that surface modification of BEA zeolite using organosilane reagent (triphenyl silane) not only reduced the coke formation but also made zeolite hydrophobic and stable. Higher yield of lighter hydrocarbons was obtained over silane treated BEA zeolite as compared to parent zeolite. It was observed that after 4 h reaction time, the modified catalysts retained its structure and phase purity while the parent catalyst showed impure phase in the XRD patterns. These findings indicate that organosilane groups attached to the external surface of catalysts protect the surface from water attack (dealumination) and made the zeolite stable in the aqueous environment. This development allows larger applications of zeolite catalysts in the presence of
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steam at high temperature for the upgrading of water-containing feedstock such as heavy oil and biomass. Acknowledgement The authors would like to acknowledge the funding provided by Saudi Aramco for supporting this work through project contract number 6600011900 as part of the Oil Upgrading theme at King Fahd University of Petroleum and Minerals.
References 1. Hyne, J., Aquathermolysis: A Synopsis of Work on the Chemical Reaction Between Water (steam) and Heavy Oil Sands During Simulated Steam Stimulation. AOSTRA Library and Information Service: 1986. 2. Hyne, J.; Clark, P.; Clarke, R.; Koo, J.; Greidanus, J.; Tyrer, J.; Verona, D., Aquathermolysis of heavy oils. Revista Tecnica Intevep 1982, 2, (2), 87-94. 3. Desouky, S., Catalytic Aquathermolysis of Egyptian Heavy Crude Oil. 4. Dejhosseini, M.; Aida, T.; Watanabe, M.; Takami, S.; Hojo, D.; Aoki, N.; Arita, T.; Kishita, A.; Adschiri, T., Catalytic cracking reaction of heavy oil in the presence of cerium oxide nanoparticles in supercritical water. Energy & Fuels 2013, 27, (8), 4624-4631. 5. Li, W.; Zhu, J.-H.; Qi, J.-H., Application of nano-nickel catalyst in the viscosity reduction of Liaohe extra-heavy oil by aqua-thermolysis. Journal of Fuel Chemistry and Technology 2007, 35, (2), 176-180. 6. Maity, S.; Ancheyta, J.; Marroquín, G., Catalytic aquathermolysis used for viscosity reduction of heavy crude oils: A review. Energy & Fuels 2010, 24, (5), 2809-2816. 7. Fan, H.; Zhang, Y.; Lin, Y., The catalytic effects of minerals on aquathermolysis of heavy oils. Fuel 2004, 83, (14), 2035-2039. 8. Hamedi Shokrlu, Y.; Babadagli, T. In Effects of nano-sized metals on viscosity reduction of heavy oil/bitumen during thermal applications, Canadian Unconventional Resources and International Petroleum Conference, 2010; Society of Petroleum Engineers: 2010. 9. Muraza, O., Hydrous pyrolysis of heavy oil using solid acid minerals for viscosity reduction. Journal of Analytical and Applied Pyrolysis 2015. 10. Fumoto, E.; Matsumura, A.; Sato, S.; Takanohashi, T., Recovery of Lighter Fuels by Cracking Heavy Oil with Zirconia− Alumina− Iron Oxide Catalysts in a Steam Atmosphere†. Energy & Fuels 2009, 23, (3), 1338-1341. 11. Funai, S.; Fumoto, E.; Tago, T.; Masuda, T., Recovery of useful lighter fuels from petroleum residual oil by oxidative cracking with steam using iron oxide catalyst. Chemical Engineering Science 2010, 65, (1), 60-65. 12. Corma, A.; Mengual, J.; Miguel, P. J., Steam catalytic cracking of naphtha over ZSM-5 zeolite for production of propene and ethene: Micro and macroscopic implications of the presence of steam. Applied Catalysis A: General 2012, 417, 220-235. 11 ACS Paragon Plus Environment
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13. Caeiro, G.; Magnoux, P.; Lopes, J.; Ribeiro, F. R.; Menezes, S.; Costa, A.; Cerqueira, H., Stabilization effect of phosphorus on steamed H-MFI zeolites. Applied Catalysis A: General 2006, 314, (2), 160-171. 14. Bakare, I. A.; Muraza, O.; Taniguchi, T.; Tago, T.; Nasser, G.; Yamani, Z. H.; Masuda, T., Steamassisted catalytic cracking of n-hexane over La-Modified MTT zeolite for selective propylene production. Journal of Analytical and Applied Pyrolysis 2015. 15. Serrano, D.; García, R.; Vicente, G.; Linares, M.; Procházková, D.; Čejka, J., Acidic and catalytic properties of hierarchical zeolites and hybrid ordered mesoporous materials assembled from MFI protozeolitic units. Journal of Catalysis 2011, 279, (2), 366-380. 16. Zapata, P. A.; Faria, J.; Ruiz, M. P.; Jentoft, R. E.; Resasco, D. E., Hydrophobic zeolites for biofuel upgrading reactions at the liquid–liquid interface in water/oil emulsions. Journal of the American Chemical Society 2012, 134, (20), 8570-8578. 17. Tago, T.; Konno, H.; Nakasaka, Y.; Masuda, T., Size-controlled synthesis of nano-zeolites and their application to light olefin synthesis. Catalysis Surveys from Asia 2012, 16, (3), 148-163. 18. Zapata, P. A.; Huang, Y.; Gonzalez-Borja, M. A.; Resasco, D. E., Silylated hydrophobic zeolites with enhanced tolerance to hot liquid water. Journal of Catalysis 2013, 308, 82-97. 19. Konno, H.; Okamura, T.; Kawahara, T.; Nakasaka, Y.; Tago, T.; Masuda, T., Kinetics of n-hexane cracking over ZSM-5 zeolites–effect of crystal size on effectiveness factor and catalyst lifetime. Chemical Engineering Journal 2012, 207, 490-496. 20. Fumoto, E.; Tago, T.; Masuda, T., Production of lighter fuels by cracking petroleum residual oils with steam over zirconia-supporting iron oxide catalysts. Energy & fuels 2006, 20, (1), 1-6. 21. Paweewan, B.; Barrie, P. J.; Gladden, L. F., Coking and deactivation during n-hexane cracking in ultrastable zeolite Y. Applied Catalysis A: General 1999, 185, (2), 259-268. 22. Mori, N.; Nishiyama, S.; Tsuruya, S.; Masai, M., Deactivation of zeolites in n-hexane cracking. Applied catalysis 1991, 74, (1), 37-52. 23. Galadima, A.; Muraza, O., Biodiesel production from algae by using heterogeneous catalysts: A critical review. Energy 2014, 78, (0), 72-83.
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Flow meter
Tape heater Temp 433 K
N2
H2O Thermo Couple
Feed
Temp 743 K
Catalyst bed Electrical heater
Tape heater Temp 373 K
Gas bag Purge
ACS Paragon Plus Fig. 1.Experimental setup ofEnvironment fixed-bed flow reactor.
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(a) BEA-Silane treated
(b) BEA-Parent 5
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Fig. 2. XRD patterns of (a) BEA-Silane treated and (b) BEA-Parent. ACS Paragon Plus Environment
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400 BEA-Silane treated
Vm [cm3 (STP) /g]
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BEA-Parent 200
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Desorption from Strong acid sites
BEA-Silane treated 360
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510 560 Temperature [K]
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Fig. 4. NH3-TPD profiles of BEA-Parent and BEA-Silane treated zeolite catalysts. ACS Paragon Plus Environment
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Coke Carbon yield (mol %-C)
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Residue C14-C20
30.9 %
Gasoline and 35.4 % kerosene Gases
6.1%
7.3%
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Without catalyst
BEA-parent-2h
Gas
Gasoline + Kerosene
C14-C20
C21-C35
C36-C44
C45+
C30+
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Fig. 5. Carbon yields (mol%-C) after 2 h reaction ACS of AR with over BEA-parent and BEA-Silane treated catalysts. Paragon Plus steam Environment
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0.005
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0.003
Alkenes 0.002
0.001 Alkanes
0 BEA-Parent-2h CO2
CO
CH4
H2
BEA-Silane treated-2h alkane
alkene
others
Fig. 6. Gas composition (mol/g-AR) after 2 h reaction of AR with steam over BEA-parent and BEA-Silane treated catalysts. ACS Paragon Plus Environment
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(b) BEA-Liquid Silane treated Reaction time: 2h
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Coke Carbon Yield (Mol%-C)
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Energy & Fuels
Residue
C21-C35 C14-C20 27 % 34.1 %
Gases
6.1 %
Feed
Gasoline and kerosene
BEA-Parent-4h
BEA-Silane treated4h
gas
Gasoline + Kerosene
C14-C20
C21-C35
C36-C44
C45+
C30+
Coke
Fig. 9. Carbon yields (mol%-C) after 4 h reaction time over (a) BEA-parent and (b) BEA-Silane treated catalysts. ACS Paragon Plus Environment
Energy & Fuels
0.014
Gas Amount Mol/ g-AR
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
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0.012
Alkenes
0.01
Alkanes
0.008 H2
0.006 0.004 0.002
CH4 0 BEA-Parent-4h CO2
CO
CH4
H2
BEA-Silane treated-4h alkane
alkene
others
Fig. 10. Gas composition (mol/g-AR) after 4 h reaction of AR with steam over BEA-parent and BEA-Silane treated ACS Paragon Plus Environment catalysts.
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Energy & Fuels
BEA-Liquid silane treated-4h
BEA-Parent-4h Feed
100
1000 Molecular weight of liquid hydrocarbons
10000
Fig. 11. Molecular weight distribution of liquid product over BEA-Parent and BEA-Liquid silane treated catalysts after 4 h reaction time. ACS Paragon Plus Environment
Energy & Fuels
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
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(a) Spent BEA-Silane treated-4h
(b) Spent BEA-Parent-4h
(c) Spent BEA-Silane treated-2h
(d) Spent BEA-Parent-2h 5
10
15
20
25
30
35
40
45
Fig. 12. XRD patterns (after reaction) of ACS (a)Paragon SpentPlus BEA-Silane treated-4h, (b) Spent BEA-Parent-4h, Environment (c) Spent BEA-Silane treated-2h, and (d) Spent BEA-Parent-2h.
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Energy & Fuels
Tetrahedrally coordinated Al in the framework
Extra framework aluminum (a) Spent BEA-Parent-4h
(b) Spent BEA-Silane treated-4h -30
0
30
60
90
120
δ27Al (ppm)
Fig. 13. Solid-state 27Al MAS NMR spectrum of Spent BEA-Parent-4h and (b) Spent BEA-Silane treated-4h. ACS(a) Paragon Plus Environment .
Energy & Fuels
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Table 1. Textural properties of parent and silane treated BEA catalysts.
Samples
SBET [m2 g-1]
SEXT [m2 g-1]
Vmicro [cm3 g-1]
BEA-Parent
422
62
0.161
BEA-Silane Treated
415
114
0.165
SBET : surface area by BET method; SEXT and Vmicro : external surface area and micro pore volume by t-plot method.
ACS Paragon Plus Environment
