Coke on HZSM-5/SAPO-34 Catalyst for Ethanol to Propylene

2014 ◽  
Vol 962-965 ◽  
pp. 751-754 ◽  
Author(s):  
Wang Feng ◽  
Bai Ting ◽  
Duan Chao ◽  
Wen Ting Qu ◽  
Xi Ling Liu ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Fixed Bed Reactor ◽  
Coke Deposition ◽  
High Yield ◽  
Active Centers ◽  
Isothermal Adsorption ◽  
Initial Stage ◽  
Adsorption Desorption

The catalytic performance on HZSM-5/SAPO-34 catalyst in ethanol to propylene was tested in continuous-flow fixed-bed reactor. Coke on HZSM-5/SAPO-34 catalyst for ethanol to propylene was studied by O2-TPO, N2isothermal adsorption–desorption and NH3-TPD.The result showed that the strong and medium acid sites were the active centers of coke deposition; Coke mainly deposited in mesoporous and some coke blocked microporous orifice; In the initial stage of reaction, the high yield of propylene may be benefited from coke deposition, which adjusted the acidity and structure of HZSM-5/SAPO-34.

Coke on Zn/Hβ Catalyst in Ethanol to Propylene

2014 ◽  
Vol 962-965 ◽  
pp. 719-722
Author(s):  
Wen Ting Qu ◽  
Ting Bai ◽  
Feng Wang ◽  
Xi Ling Liu ◽  
Xin Zhang
Keyword(s):  
Physicochemical Properties ◽  
Continuous Flow ◽  
External Surface ◽  
Fixed Bed ◽  
Strong Acid ◽  
Acid Sites ◽  
Fixed Bed Reactor ◽  
Isothermal Adsorption ◽  
Strong Acid Sites ◽  
Adsorption Desorption

Coke on Zn/Hβ catalyst in ethanol to propylene was studied in continuous-flow fixed-bed reactor. The physicochemical properties of these fresh and used catalysts were characterized by NH3-TPD, N2 isothermal adsorption-desorption and TPO. These results showed that the medium and strong acid sites might be responsible for the production of coke and coke mainly deposited on external surface and microporous mouth. In addition, the coke might be consisted of soft coke and hard coke.

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).

STUDY ON NANO COPPER-BASED CATALYSTS FOR THE HYDROGENATION OF METHYL 3-HYDROXYPROPIONATE TO 1, 3-PROPANEDIOL

2009 ◽  
Vol 16 (03) ◽  
pp. 343-349 ◽  
Author(s):  
YUZHOU YING ◽  
KANKA FENG ◽  
ZHIGUO LV ◽  
ZHENMEI GUO ◽  
JINSHENG GAO
Keyword(s):  
Fixed Bed ◽  
Side Reaction ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Precipitation Method ◽  
Active Components ◽  
Analysis Technique ◽  
Co Precipitation ◽  
Nano Catalysts ◽  
Adsorption Desorption

Nano copper-based catalysts were prepared by co-precipitation method and the performance of catalytic hydrogenation for methyl 3-hydroxypropionate (MHP) to 1, 3-propanediol (1, 3-PDO) on the nano catalysts were studied under a high-pressure microcontinuum fixed-bed reactor. The effects of structure, texture, and composition of the catalysts on the catalytic performance were investigated by characterizing the catalysts with XRD, TG–DTG, SEM, and N 2 adsorption/desorption analysis technique. The results showed that addition of promoters enhanced the activity and selectivity of copper-based catalysts, which promoted the dispersion of the active components effectively and stabilized the active center of the catalysts. Especially, the copper-based catalyst of loaded P could restrain side-reaction effectively and improve selectivity obviously, the conversion of MHP and the selectivity of 1, 3-PDO could be 91.30% and reach 90.15%, respectively.

Effect of Steam Treatment on Catalytic Performance of La2O3-HZSM-5 for Methylation of Toluene with Methanol

2012 ◽  
Vol 629 ◽  
pp. 381-385 ◽  
Author(s):  
Jun Hui Li ◽  
Zhong Hua Hu ◽  
Ya Nan Wang ◽  
Hao Xiang ◽  
Zhi Rong Zhu
Keyword(s):  
High Selectivity ◽  
Fixed Bed ◽  
Shape Selectivity ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Fixed Bed Reactor ◽  
Steam Treatment ◽  
By Products ◽  
Poor Stability ◽  
Excellent Catalytic Performance

Methylation of toluene with methanol to synthesize p-Xylene was performed in a fixed-bed reactor. HZSM-5 zeolite as a catalyst was prepared by modification with La2O3. In addition, effect of steam treatment for La2O3-modified HZSM-5 on its catalytic performance was investigated as well. The properties of as-prepared catalysts were characterized by XRD, BET and NH3-TPD. The results indicate that modification with La2O3can narrow the size of HZSM-5 channel effectively. And more than 90% selectivity of p-Xylene is obtained over HZSM-5 with loading of 24% and 30% La2O3. However, above La2O3-modified HZSM-5 with high-selectivity exhibit a poor stability for time on-stream of the methylation reaction. Steam treatment of La2O3-modified HZSM-5 can improve its stability and shape selectivity, decreasing by-products. These effects can be attributed to distortion & narrowing of HZSM-5 channel and reduction of HZSM-5 strong Bronsted acid sites during steam treatment. As a result, the excellent catalytic performance is obtained over 24.0% La2O3-modified HZSM-5 by steam treatment at 773 K for 1.0 h, being 23% conversion of toluene, 93% selectivity of p-Xylene during time on-stream.

scholarly journals Effect of Catalyst Crystallinity on V-Based Selective Catalytic Reduction with Ammonia

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1452
Author(s):  
Min Seong Lee ◽  
Sun-I Kim ◽  
Myeung-jin Lee ◽  
Bora Ye ◽  
Taehyo Kim ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Fixed Bed Reactor ◽  
Scr Catalysts ◽  
Catalyst Systems ◽  
The One ◽  
No2 Formation

In this study, we synthesized V2O5-WO3/TiO2 catalysts with different crystallinities via one-sided and isotropic heating methods. We then investigated the effects of the catalysts’ crystallinity on their acidity, surface species, and catalytic performance through various analysis techniques and a fixed-bed reactor experiment. The isotropic heating method produced crystalline V2O5 and WO3, increasing the availability of both Brønsted and Lewis acid sites, while the one-sided method produced amorphous V2O5 and WO3. The crystalline structure of the two species significantly enhanced NO2 formation, causing more rapid selective catalytic reduction (SCR) reactions and greater catalyst reducibility for NOX decomposition. This improved NOX removal efficiency and N2 selectivity for a wider temperature range of 200 °C–450 °C. Additionally, the synthesized, crystalline catalysts exhibited good resistance to SO2, which is common in industrial flue gases. Through the results reported herein, this study may contribute to future studies on SCR catalysts and other catalyst systems.

scholarly journals Catalytic Performance of Phosphorus Incorporated HZSM-5 in Coupling Transformation of Methanol with 1-butene to Propylene

2021 ◽  
Vol 72 (3) ◽  
pp. 33-44
Author(s):  
Haifeng Tian ◽  
Yongyong Nan ◽  
Jinlong Lv ◽  
Fei Zha ◽  
Xiaohua Tang ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
N2 Adsorption ◽  
Facile Hydrothermal Method ◽  
Phosphorus Species ◽  
Coupling Transformation ◽  
Ft Ir ◽  
Adsorption Desorption

Directly incorporated phosphorus species into the framework of HZSM-5 zeolite (H[P, Al]-ZSM-5) was successfully synthesized by the facile hydrothermal method. It was characterized by employing XRD, ICP-OES, SEM, FT-IR, N2 adsorption-desorption, NH3-TPD, XPS and TG-DTA, respectively. The effects of the phosphorus species content, temperature, WHSV, and the molar ratio of methanol/1-butene in coupling transformation of methanol with 1-butene to propylene catalyzed by H[P, Al]-ZSM-5 in a fixed bed reactor were studied systematically. Tests have suggested the acid content and specific surface area of H[P, Al]-ZSM-5 are reduced. Under the condition of reaction temperature at 550�Z, molar ratio of methanol/1-butene to 1.0, reaction pressure at 0.1 MPa and WHSV= 3.53 h-1, the P-modified HZSM-5 zeolite (with the P2O5 molar composition of 0.4 )the selectivity and yield of propylene are 35.6% and 32.5%, respectively.

scholarly journals Activity Evaluation of CoMo Nanoparticles Supported on Meso-microporous Composites in Dibenzothiophene Hydrodesulphurization

2019 ◽  
Vol 15 (1) ◽  
pp. 112-118
Author(s):  
Nastaran Parsafard ◽  
Mohammad Hasan Peyrovi ◽  
Zahra Mohammadian ◽  
Niloofar Atashi
Keyword(s):  
Activation Energy ◽  
High Surface ◽  
High Surface Area ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Impregnation Method ◽  
Wet Impregnation ◽  
Ft Ir ◽  
Adsorption Desorption

CoMo-supported mesoporous catalysts were synthesized by 50 wt% of HZSM-5 and 50 wt% of FSM-16, KIT-6, and MCM-48. These catalysts were prepared by the wet-impregnation method and pre-sulfided with CS2. The catalytic performance was evaluated for HDS reaction of dibenzothiophene over a temperature range of 250-400 °C in a micro fixed-bed reactor under atmospheric pressure. The supported CoMo bimetallic catalysts were characterized by XRD, XRF, FT-IR, N2 adsorption-desorption, and SEM. The CoMo/KIT-6/HZSM-5 indicate higher activity than other catalysts at 400 °C for dibenzothiophene hydrodesulphurization. Also, the best selectivity to cyclohexylbenzene (CHB) is related to CoMo/FSM-16/HZSM-5. The activation energy was also calculated for all prepared catalysts for the conversions of less than 10%; according to which, the activation energy for CoMo/KIT-6/HZSM-5 is less than other catalysts (~21 kJ/mol) which can be related to the appropriate pore size and high surface area of the support. Copyright © 2020 BCREC Group. All rights reserved 

Effect of Shape and Modification over ZSM-5 Catalyst on Methanol to Gasoline

2014 ◽  
Vol 1008-1009 ◽  
pp. 295-299 ◽  
Author(s):  
Xiao Feng Gao ◽  
Chuan Min Ding ◽  
Wei Li Liu ◽  
Lin Feng Fan ◽  
Gang Song ◽  
...  
Keyword(s):  
Molecular Sieves ◽  
Coke Formation ◽  
Fixed Bed ◽  
Mesoporous Structure ◽  
Catalytic Performance ◽  
Carbon Accumulation ◽  
Fixed Bed Reactor ◽  
Coke Deposition ◽  
Methanol To Gasoline ◽  
Naoh Solution

Fixed bed reactor was used to explore the catalytic performance of ZSM-5 catalysts with the forms of flake and strip in methanol to gasoline (MTG) reaction. The catalyst samples were characterized by XRD, BET and SEM. The strip ZSM-5 catalyst was modified by 0.4 Molar NaOH solution, which was denoted by TZSM-5/AT. The results show that ZSM-5 molecular sieves could be effectively dispersed to prevent carbon accumulation when extruded with binder. So the coke deposition resistance capacity of strip ZSM-5 has significantly enhancement comparing with flake ZSM-5. Mesoporous structure in strip zeolites formed after NaOH treatment, which could prevent coke formation and further improve catalyst life. The conversion of methanol remains above 80% over 140 hours on alkali-modified strip ZSM-5 operating at atmospheric pressure, 380°C and weight hourly space velocities (WHSV) of 1.5 h-1.

scholarly journals Comparative Study of Different Acidic Surface Structures in Solid Catalysts Applied for the Isobutene Dimerization Reaction

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1235 ◽  
Author(s):  
José M. Fernández-Morales ◽  
Eva Castillejos ◽  
Esther Asedegbega-Nieto ◽  
Ana Belén Dongil ◽  
Inmaculada Rodríguez-Ramos ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Fixed Bed Reactor ◽  
Catalyst Stability ◽  
Molar Ratio ◽  
Solid Catalysts ◽  
Catalytic Materials ◽  
Materials Used

Dimerization of isobutene (IBE) to C8s olefins was evaluated over a range of solid acid catalysts of diverse nature, in a fixed bed reactor working in a continuous mode. All catalytic materials were studied in the title reaction performed between 50–250 °C, being the reaction feed a mixture of IBE/helium (4:1 molar ratio). In all materials, both conversion and selectivity increased with increasing reaction temperature and at 180 °C the best performance was recorded. Herein, we used thermogravimetry analysis (TGA) and temperature programmed desorption of adsorbed ammonia (NH3-TPD) for catalysts characterization. We place emphasis on the nature of acid sites that affect the catalytic performance. High selectivity to C8s was achieved with all catalysts. Nicely, the catalyst with higher loading of Brønsted sites displayed brilliant catalytic performance in the course of the reaction (high IBE conversion). However, optimum selectivity towards C8 compounds led to low catalyst stability, this being attributed to the combined effect between the nature of acidic sites and structural characteristics of the catalytic materials used. Therefore, this study would foment more research in the optimization of the activity and the selectivity for IBE dimerization reactions.

Conversion of Multicyclic Hydrocarbons to Mono-Aromatic Hydrocarbons Over CoMo/Zeolite Socony Mobil-5 Catalysts

2021 ◽  
Vol 21 (7) ◽  
pp. 3819-3823
Author(s):  
Huiji Ku ◽  
Seung Kyo Oh ◽  
Kyuri Kim ◽  
Young-Kwon Park ◽  
Jong-Ki Jeon
Keyword(s):  
Fixed Bed ◽  
Chemical Properties ◽  
Strong Acid ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Weak Acid ◽  
Fixed Bed Reactor ◽  
Nanoporous Structure ◽  
Bead Type ◽  
Catalytic Cracking Reaction

This study focuses on analyzing the effects of the SiO2/Al2O3 ratio of a support on the physico-chemical properties of bead-type CoMo/HZSM-5 catalysts and on the catalytic performance during the hydrocracking reaction of PFO. CoMo/HZSM-5 catalysts were prepared by an incipient wetness method. Subsequently, binder-added catalysts were molded into the bead type catalysts. The N2 adsorption-dersorption results clearly indicate that the nanoporous structure was well developed in the bead-type CoMo/HZSM-5 catalyst. The CoMo/HZSM-5(30) catalyst not only possessed the highest number of acid sites but also showed the highest ratio of strong acid to weak acid sites. Moreover, the Lewis acid/Brönsted acid site ratio is highest with the CoMo/HZSM-5(30) catalysts. A hydrocracking reaction of PFO over the bead-type CoMo/HZSM-5 catalysts was conducted at 400 °C and under 40 atm in a fixed-bed reactor. The bead-type CoMo/HZSM-5(30) catalyst showed the highest BTXE yield with a sum of BTXE outcome of 43.0% in the catalytic cracking reaction of PFO, which is attributed to the synergistic combination of suitable acidity and hierarchical porosity.

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