Modification of ZSM-5 Zeolite in order to Improve the Yield of Light Olefins during Cracking of Oil and Plant Materials

2018 ◽  
Vol 18 (4) ◽  
pp. 31-40
Author(s):  
V. P. Doronin ◽  
P. V. Lipin ◽  
O. V. Potapenko ◽  
V. V. Vysotsky ◽  
T. I. Gulyaeva ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Alkali Treatment ◽  
Total Yield ◽  
Acid Sites ◽  
Vacuum Gasoil ◽  
Light Olefins ◽  
Plant Oil ◽  
Plant Materials

The influence of modifying HZSM-5 zeolite as a component of a bizeolite catalyst in transformations of hydrotreated vacuum gasoil, plant oil, and a mixture of vacuum gasoil and plant oil was studied. The modification with phosphorus was established to decrease the specific surface area and meso- and macropore volumes in HZSM-5 zeolite; the higher phosphorus content, the lower main characteristics of the zeolite porous structure. A decrease in the total acidity of P/HZSM-5 and quantitative redistribution between weak and moderate acid sites also was observed. Testing of the zeolites in catalytic cracking revealed that the phosphorus modification favored an increase in the total yield of propane-propylene and butane-butylene fractions containing olefins in high proportions. Alkali treatment of HZSM-4 zeolite with a high silicate module resulted in a higher silicon extraction and in a considerable increase in the specific surface area of mesopores. In addition, strong acid sites of the zeolite were transformed to weaker ones and/or their exposure changed due to partial silicon removal.

scholarly journals Modification of natural clinoptilolite and ZSM-5 with different oxides and studying of the obtained products in lignin pyrolysis

2015 ◽  
Vol 80 (5) ◽  
pp. 717-729 ◽  
Author(s):  
Jelena Milovanovic ◽  
Ruth Stensrød ◽  
Elisabeth Myhrvold ◽  
Roman Tschentscher ◽  
Michael Stöcker ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Acid Sites ◽  
X Ray ◽  
Ion Exchange Reaction ◽  
Catalytic Experiment ◽  
Bet Method ◽  
Polycyclic Aromatic ◽  
Natural Clinoptilolite

In this work, different metal oxides (MO) supported on two types of zeolites: 1) natural clinoptilolite (NZ) and 2) synthetic zeolite, ZSM-5 were prepared and tested as catalysts in the fast pyrolysis of hardwood lignin. NZ was modified with the CaO and MgO by a simple two steps procedure consisting of an ion exchange reaction and a subsequent calcination at 773 K. The synthetic ZSM-5 was modified with several MO species (Ni, Cu, Ca, Mg) by a wet impregnation and calcination at 873 K. ?he prepared catalysts were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDS) and measurement of specific surface area (BET method). Acid sites were characterized and quantified by pyridine (py) absorption using Fourier transform infrared spectroscopy (FTIR). The catalysts exhibit catalytic activity depanding on modification, reaction temperature and of the MO contents. The highest yield of useful phenol in bio-oil was obtained with NiO/ZSM-5 (34.8 wt.%) which exhibits the highest specific surface area and the highest concetration of Br?nsted and Lewis acid sites. The studied catalysts did not increase significantly the content of polycyclic aromatic hydrocarbons (PAHs) and heavy compounds compared to non-catalytic experiment.

scholarly journals Effect of Acid Treatment on the Properties of Zeolite Catalyst for Straight-Run Gasoline Upgrading

2021 ◽  
Vol 1 (4) ◽  
pp. 1-1
Author(s):  
Ludmila Velichkina ◽  
◽  
Yakov Barbashin ◽  
Alexander Vosmerikov ◽  
◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Acid Treatment ◽  
Catalytic Properties ◽  
Fixed Bed ◽  
Acid Sites ◽  
Gasoline Fraction ◽  
Zeolite Catalysts ◽  
Acidic Properties

The objective of this research was to analyze the effect of different concentrations of nitric and hydrochloric acids on the structural, acidic, and catalytic properties of a post-synthetic treated ZSM-5 type zeolite at various temperatures. The properties of zeolite catalysts were determined using different methods, such as the Brunauer-Emmett-Teller (BET) method for specific surface area, temperature-programmed desorption (TPD) of ammonia method for acidic properties, and a flow-through unit with fixed bed catalyst (with upgrading straight-run gasoline fraction of oil) for catalytic activities of initial zeolite and acid-treated samples. The structural and acidic properties of both untreated and treated zeolites were investigated, and the effect of acid treatment on the catalytic properties of the samples in the course of upgrading the straight-run gasoline fraction of oil was determined. The post-synthetic treatment with aqueous nitric acid increased the specific surface area and volume of micropores of ZSM-5 zeolite, while the treatment with aqueous hydrochloric acid led to the formation of mesopores. Acid treatments of zeolite decreased the number of acid sites, mainly due to diminished concentration of low-temperature sites. The yield of liquid products in the conversion of straight-run gasoline fraction of oil, i.e., generation of high-octane gasolines with improved environmental features, was increased using acid-treated zeolites, which was due to the decrease in arene content.

scholarly journals Synthesis and Physico-Chemical Characterization of CeO2/ZrO2-SO42- Mixed Oxides

2017 ◽  
Vol 56 (2) ◽  
Author(s):  
Juan Manuel Hernández-Enríquez ◽  
Rebeca Silva-Rodrigo ◽  
Ricardo García-Alamilla ◽  
Luz Arcelia García-Serrano ◽  
Brent Edward Handy ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Synthesis Method ◽  
Chemical Characterization ◽  
Acid Sites ◽  
Oxide Content ◽  
Physico Chemical

Environmentally friendly solid-acid catalysts CeO<sub>2</sub>/ZrO<sub>2</sub>-SO<sub>4</sub><sup>2-</sup> were prepared by the sol gel method varying CeO<sub>2</sub> content (10, 20 and 30 wt%) and using sulfation <em>in situ</em>, maintaining the sulfate ions amount present in the materials at 20 wt%. ZrO<sub>2</sub> and ZrO<sub>2-</sub>SO<sub>4</sub><sup>2-</sup> were also prepared for comparison proposes using the same synthesis method. The materials were characterized by X-ray diffraction, nitrogen physisorption, potentiometric titration with <em>n</em>-butylamine, decomposition of 2-propanol and <em>n</em>-pentane isomerization. The specific surface area of ZrO<sub>2-</sub>SO<sub>4</sub><sup>2-</sup> was high (160 m<sup>2</sup>/g) compared with the unmodified ZrO<sub>2</sub> (80 m<sup>2</sup>/g), however this area decreased with increasing the CeO<sub>2</sub> content (37-100 m<sup>2</sup>/g). There was no significant effect of CeO<sub>2</sub> on the tetragonal structure of ZrO<sub>2-</sub>SO<sub>4</sub><sup>2-</sup>. The variation of acid sites amount runs parallel to the change of specific surface area. The acid sites amount decreased with increasing cerium oxide content. The decomposition of 2-propanol results fundamentally in the formation of dehydration products such as propylene and diisopropyl ether, both involving acid sites. In addition, a good performance during the <em>n</em>-pentane isomerization was observed for these materials. The selectivity towards isopentane reaches 84% when the Pt/CeO<sub>2</sub>/ZrO<sub>2-</sub>SO<sub>4</sub><sup>2-</sup> catalyst with the highest CeO<sub>2</sub> content was used.

Acid-based modified NiCo2O4 as high-performance supercapacitor electrode materials

2021 ◽  
pp. 2150200
Author(s):  
Wenbo Geng ◽  
Qing Wang ◽  
Jianfeng Dai ◽  
Haoran Gao
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrode Material ◽  
High Performance ◽  
Electrode Materials ◽  
Alkali Treatment ◽  
Treatment Method ◽  
Supercapacitor Electrode ◽  
Supercapacitor Electrode Materials

The performance of supercapacitor electrode materials was greatly affected by the specific surface area. The urchin-like NiCo2O4 was transformed into porous NiCo2O4 (AA-NiCo2O[Formula: see text] using the acid–alkali treatment method. The specific surface area of AA-NiCo2O4 was 165.0660 m2/g, which was about three times larger than that of NiCo2O4. The specific capacitance of the AA-NiCo2O4 was enhanced significantly (1700 F/g at 1 A/g), and AA-NiCo2O4 possesses good rate capacitance (1277 F/g at 10 A/g). This is mainly attributed to the larger specific surface area, fast and convenient electron–ion transport and redox reaction. Therefore, AA-NiCo2O4 is a promising high-performance supercapacitor electrode material.

SEM and BET Methods for Investigating the Structure and Morphology of Co - Ce Catalysts for Production of Light Olefins

2008 ◽  
Vol 61 (2) ◽  
pp. 144 ◽  
Author(s):  
Ali A. Mirzaei ◽  
Maryam Galavy ◽  
Vahid Eslamimanesh
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Catalytic Performance ◽  
Light Olefins ◽  
Molar Ratio ◽  
Surface Areas ◽  
Preparation Conditions ◽  
Bet Specific Surface Area ◽  
Before And After

Co–Ce catalysts prepared by the coprecipitation method were tested for production of light olefins. The effect of different preparation conditions including the [Co]/[Ce] molar ratio, aging time, calcination conditions, different supports, and loading of optimum support on the structure and catalytic performance of different catalysts were investigated. It was found that catalyst containing 80% Co/20% Ce/15% SiO2, which was aged for 2 h and calcined at 600°C for 6 h, is the optimum modified catalyst for the conversion of synthesis gas to light olefins. Characterization of both precursors and calcined catalysts (before and after the test) was carried out using scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) specific surface area measurements. The morphology of the catalysts was investigated by SEM and the surface areas of these catalysts were studied by BET. It was shown that all of the different preparation variables influenced the morphology and also the specific surface area of the catalyst precursors and calcined catalysts.

Characterization of Fluorinated Hβ Zeolite with NH4F

2010 ◽  
Vol 160-162 ◽  
pp. 524-528
Author(s):  
Zhen Tian ◽  
Nai Ci Bing
Keyword(s):  
Aqueous Solution ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Acid Sites ◽  
Total Acid ◽  
Hβ Zeolite ◽  
Surface Performance

Fluorination of the zeolite has been known as a useful method to modify its acidity and surface performance. In this paper, a set of zeolite Hβ were impregnated with aqueous solution of NH4F. The effects of NH4F impregnation on the structure and acidity of Hβ was investigated by XRD, BET measurements, NH3-TPD, and Py-IR. The change of specific surface area and pore volume of the fluorinated samples with NH4F can be attributed the reaction of NH4F with non-framework and framework aluminum. The fluorination increases the strength and changes the distribution of the acid sites; the fluorination also leads to the decrease of the total acid sites and the Brönsted acid sites due to the dealuminization of the samples and the substitution of the OH- by fluorine atoms.

scholarly journals Sol-gel preparation and properties of amorphous iron-containing aluminosilicate

2020 ◽  
Vol 64 (11) ◽  
pp. 102-107
Author(s):  
Lyubov V. Furda ◽  
◽  
Evgeniya A. Tarasenko ◽  
Sofya N. Dudina ◽  
Olga E. Lebedeva ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Sol Gel ◽  
Reference Sample ◽  
Acid Sites ◽  
Molar Ratio ◽  
Indicator Method ◽  
Gel Preparation

The objective of the present study includes a modification of synthetic aluminosilicate with iron cations and an estimation of the modificator influence at structure and properties of the aluminosilicate. The iron-containing aluminosilicate (Si/Al = 4.72) with an Al/Fe molar ratio of 5:1 was prepared by the sol-gel method at pH = 1-2. Amorphous aluminosilicate (Si/Al = 4.72), which was synthesized by analogous procedure, was applied as a reference sample. By scanning electron microscopy, it was found that the powders had particles of 1-20 micrometers in size. The results of low-temperature adsorption-thermal desorption of nitrogen showed that the modification with Fe3+ ions affected the specific surface area and porosity of the material under study. The iron-containing sample has a higher specific surface area and pore volume comparing to the initial aluminosilicate. The Hammett indicator method was used to evaluate the surface centers of the samples. It was found that the materials under study were characterized by the presence of active sites with pKax values in the range from - 4.4 to 12.8 with a pronounced maximum at pKax = 1.02. For an iron-containing sample, the concentration of acid sites significantly decreases at pKax = 1.02, while at pKax 0.80, 1.03, 2.10, 2.50, 4.10, 5.00, 8.00, and 12.80, an increase in the number of acid sites is observed. The values of the Hammett function are practically the same for the studied samples and characterizes them as materials of medium acidity. For iron-containing aluminosilicate, the larger number of active sites was noted, it amounted to 313.5 mmol/g.

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