Hydrothermal Modification Effect on the Catalyst for Etherification

2013 ◽  
Vol 805-806 ◽  
pp. 1368-1375
Author(s):  
Xi Ming Yan ◽  
Ming Ke ◽  
Zhao Zheng Song
Keyword(s):  
Active Component ◽  
Fixed Bed ◽  
Strong Acid ◽  
Weak Acid ◽  
Fixed Bed Reactor ◽  
Total Acid ◽  
Surface Areas ◽  
Hydrothermal Modification ◽  
Different Temperatures ◽  
Loading Amount

Etherification of isoamylene with methanol has been carried out over the γ-Al2O3/Hβ catalyst in a fixed bed reactor, catalysts were hydrothermal modified at different temperatures and time. The results show that the appropriate loading amount of active component Hβ is 20%; Hydrothermal modification is an effective way to improve the etherification activity, When γ-Al2O3/20%Hβ catalyst was hydrothermal modified at 573K for 3 hours, the isoamylene conversion is the highest, reach up to 51.95%, about 25% higher than the untreated one. From results of BET, XRD, and NH3-TPD characterization can be seen that hydrothermal modification does not change crystalline structure of the catalyst, but specific surface areas decrease together with pore volume and pore size increase, it also reduced the total acid volume of catalyst and improved the surface acid distribution of weak acid and strong acid.

scholarly journals Methanol Dehydration to Dimethyl Ether over Modified γ-Al2O3 with Acid, Base and Zeolite (NaA and NaX)

2020 ◽  
Vol 20 (2) ◽  
pp. 109
Author(s):  
Maria Ulfah ◽  
Hendra Suherman ◽  
Melia Laniwati ◽  
IGBN Makertihartha ◽  
Subagjo Subagjo
Keyword(s):  
Surface Acidity ◽  
Fixed Bed ◽  
Strong Acid ◽  
Acid Sites ◽  
Weak Acid ◽  
Fixed Bed Reactor ◽  
Methanol Dehydration ◽  
Zeolite Nax ◽  
Zeolite Naa ◽  
Strong Acid Sites

The effect of acids, bases, zeolite NaA and zeolite NaX impregnation to g-Al2O3 on the catalyst characteristics and activity against methanol dehydration reaction were investigated. The catalyst characteristics include N2 physisorption, X-ray diffraction (XRD), and temperature-programmed desorption of ammonia (NH3-TPD) in addition to catalytic dehydration of methanol performed in a micro fixed-bed reactor at 270°C and 1 atm. The results of XRD characterization showed no changes related to the modification of alumina over acids, bases, and zeolite NaA and zeolite NaX. Therefore, the modification did not have any effect on the crystalline structure of alumina. The textural and surface acidity of g-Al2O3 changed post addition of acids, bases, zeolite NaA and zeolite NaX. NH3-TPD analysis results demonstrated that synthesized g-Al2O3 has three types of acid sites: weak, medium, and strong; however, the weak acid sites were not observed on alumina catalysts modified phosphate, KOH, zeolite NaA, and zeolite NaX. Furthermore, the concentration of strong acid sites increased in the catalyst containing KOH. The catalytic test results showed that the untreated g-Al2O3 catalyst gave prominent activity in dehydration of methanol compared to the treated catalyst following the number and strength of acid sites. 

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.

Reaction Mechanism for CCl2F2 Catalytic Decomposition over MoO3/ZrO2

2013 ◽  
Vol 295-298 ◽  
pp. 326-330 ◽  
Author(s):  
Tian Cheng Liu ◽  
Yu Jiao Guo ◽  
Ping Ning ◽  
Ming Long Yuan
Keyword(s):  
Reaction Mechanism ◽  
Main Product ◽  
Solid Acid ◽  
Fixed Bed ◽  
Catalytic Decomposition ◽  
Strong Acid ◽  
Acid Sites ◽  
Fixed Bed Reactor ◽  
Surface Intermediate ◽  
Strong Acid Sites

Catalytic hydrolysis decomposition of dichlorodifluoromethane (CCl2F2) in the presence of water vapor and oxygen was studied over a series of solid acids using a fixed-bed reactor. Solid acid MoO3/ZrO2 displayed the highest activity, over which the conversion of CCl2F2 reached 100 % at 250 °C. CO2 was the main-product and the selectivity to CClF3 remained lower than 28.0 %. CO was not detected as by-product. The decomposition activity depended on the calcination temperature and the ZrO2 content. The activity of solid acid MoO3/ZrO2 correlates well with its specific surface area and the amount of medium-strong acid sites on the surface. To explain the reaction mechanism for CCl2F2 catalytic decomposition over MoO3/ZrO2, a surface intermediate, Osurface-CF2-Osurface is proposed.

On efficiency of vanadium-oxide promoter in cobalt Fischer – Tropsch catalysts

2021 ◽  
Vol 1 (1-2) ◽  
pp. 15
Author(s):  
Elham Yaghoobpour ◽  
Yahya Zamani ◽  
Saeed Zarrinpashne ◽  
Akbar Zamaniyan
Keyword(s):  
Vanadium Oxide ◽  
Active Sites ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Bet Surface Area ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Fischer Tropsch ◽  
Co Conversion ◽  
Loading Amount

Promoters and their loading amount have crucial roles in cobalt Fischer – Tropsch catalysts. In this regard, the effects of vanadium oxide (V2O5) as a proposed promoter for Co catalyst supported on TiO2 have been investigated. Three catalysts with 0, 1, and 3 wt.% of V2O5 promoter loading are prepared by the incipient wetness impregnation method, and characterized by the BET surface area analyzer, XRD, H2-TPR, and TEM techniques. The fixed-bed reactor was employed for their evaluations. It was found that the catalyst containing 1 wt.% V2O5 has the best performance among the evaluated catalysts, demonstrating remarkable selectivity: 92 % C5+ and 5.7 % CH4, together with preserving the amount of CO conversion compared to the unpromoted catalyst. Furthermore, it is reported that the excess addition of V2O5 promoter (> 1 wt.%) in the introduced catalyst leads to the detrimental effect on the CO conversion and C5+ selectivity, mainly owing to diminished active sites by V2O5 loading.

Effects of Alkali and Alkaline Earth Metals on NOx Reduction in Coke Combustion

2013 ◽  
Vol 634-638 ◽  
pp. 522-525 ◽  
Author(s):  
Yan Guang Chen ◽  
Hong Jing Han ◽  
Jia Lu ◽  
Dan Dan Li ◽  
Jin Lian Li ◽  
...  
Keyword(s):  
Alkaline Earth ◽  
Nox Reduction ◽  
Combustion Process ◽  
Fixed Bed ◽  
Alkaline Earth Metals ◽  
Reduction Ratio ◽  
Nox Emission ◽  
Fixed Bed Reactor ◽  
Impregnation Method ◽  
Loading Amount

A series of coke samples with loading alkali and alkaline earth metals were prepared by the impregnation method, the NOx emission were investigated in a silica fixed bed reactor in the combustion process of raw coke and coke modified by Na, K, Ca and Mg. The results show that Na, K, Ca and Mg play in-situ catalytic effects on the NOx reduction reactions. When the loading amount of Na2CO3 is 2.0%, the NOx reduction ratio was around 17.4%, when the loading of K2CO3 is 2.0%, the amount of NOx emission is reduced by 26.5%. When the loading of CaCl2 is 2.0%, the amount of NOx emission is reduced by 22.3%. When the loading of MgCl2 is 2.0%, the NOx reduction ratio is about 10.9%.

Experimental Study of the Reforming of Methane with Carbon Dioxide over Coal Char

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Yanbing Li ◽  
Rui Xiao ◽  
Baosheng Jin ◽  
Huiyan Zhang
Keyword(s):  
Carbon Dioxide ◽  
Flow Rate ◽  
Fixed Bed ◽  
Coke Oven ◽  
Fixed Bed Reactor ◽  
Internal Diameter ◽  
Generation System ◽  
Coke Oven Gas ◽  
Surface Areas ◽  
Conversion Of Methane

As one of the fundamental issues of the new poly-generation system on the basis of gasification gas and coke oven gas, carbon dioxide reforming of methane experiments have been performed over coal chars derived from different parent coals in a lab-scale fixed-bed reactor (internal diameter 12 mm, length 700 mm). The char derived from TongChuan coal exhibited higher activity than other samples employed under the same conditions. After the reforming reaction, the char samples were covered with different amounts of carbon deposition which resulted in the surface areas decrease. As the flow rate of feed gas increased from 200 ml/min to 600 ml/min over the Xuzhou char sample at 1050 degrees Celsius, the conversion of methane decreased from 52.7% to 17.5% and the H2 /CO dropped from 0.75 to 0.55. While maintaining the flow rate of CO2 at 20ml/min at 1050 degrees Celsius, the mole ratio of reactants CH4/CO2 was varied from 1 to 1.75 which led to the H2/CO ratio increase from 0.75 to 1.2.

Effect of Hydrothermal Conditions on Isomerization Activity of Pt/SO42--ZrO2

2010 ◽  
Vol 132 ◽  
pp. 183-191
Author(s):  
Juan Juan Zhang ◽  
Yue Qin Song ◽  
Xiao Long Zhou ◽  
Cheng Lie Li ◽  
Jin An Wang ◽  
...  
Keyword(s):  
Sulfur Content ◽  
Crystalline Structure ◽  
Fixed Bed ◽  
Strong Acid ◽  
Acid Sites ◽  
Zirconium Hydroxide ◽  
Fixed Bed Reactor ◽  
Isomerization Reaction ◽  
Hydrothermal Conditions ◽  
Hydrous Zirconia

Pt/SO42--ZrO2 catalysts (PSZ) were prepared by using a series of hydrous zirconia as support synthesized via a hydrothermal method. The catalytic performances of these catalysts were evaluated in the n-hexane isomerization in a fixed bed reactor. The crystalline structure, acidity, reduction properties, textural texture, and sulfur content were characterized by XRD, NH3-TPD, H2-TPR, N2 adsorption and thermal analysis. The experimental results indicated that the hydrothermal ageing of zirconium hydroxide led to great changes in the crystalline structure of hydrous zirconia support, sulfur content, and the acidity of PSZ. The abundant strong acid sites and high sulfur content were essential but insufficient to achieve a PSZ catalyst with high isomerization activity. Too weak or too strong interaction between sulfur species and zirconia in the catalysts was unfavorable to the isomerization reaction. The presence of considerable sulfate species interacting moderately with zirconia was crucial to high isomerization activity.

scholarly journals Effect of Preparation Method on ZrO2-Based Catalysts Performance for Isobutanol Synthesis from Syngas

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 752 ◽  
Author(s):  
Yingquan Wu ◽  
Li Tan ◽  
Tao Zhang ◽  
Hongjuan Xie ◽  
Guohui Yang ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Carbon Chain ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Chain Growth ◽  
Impregnation Method ◽  
Surface Areas ◽  
Co Precipitation ◽  
Diffuse Reflectance Infrared

Two types of amorphous ZrO2 (am-ZrO2) catalysts were prepared by different co-precipitation/reflux digestion methods (with ethylenediamine and ammonia as the precipitant respectively). Then, copper and potassium were introduced for modifying ZrO2 via an impregnation method to enhance the catalytic performance. The obtained catalysts were further characterized by means of Brunauer-Emmett-Teller surface areas (BET), X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR), and In situ diffuse reflectance infrared spectroscopy (in situ DRIFTS). CO hydrogenation experiments were performed in a fixed-bed reactor for isobutanol synthesis. Great differences were observed on the distribution of alcohols over the two types of ZrO2 catalysts, which were promoted with the same content of Cu and K. The selectivity of isobutanol on K-CuZrO2 (ammonia as precipitant, A-KCZ) was three times higher than that on K-CuZrO2 (ethylenediamine as precipitant, E-KCZ). The characterization results indicated that the A-KCZ catalyst supplied more active hydroxyls (isolated hydroxyls) for anchoring and dispersing Cu. More importantly, it was found that bicarbonate species were formed, which were ascribed as important C1 species for isobutanol formation on the A-KCZ catalyst surface. These C1 intermediates had relatively stronger adsorption strength than those adsorbed on the E-KCZ catalyst, indicating that the bicarbonate species on the A-KCZ catalyst had a longer residence time for further carbon chain growth. Therefore, the selectivity of isobutanol was greatly enhanced. These findings would extend the horizontal of direct alcohols synthesis from syngas.

Using Titania Photocatalysts to Degrade Toluene in a Combined Adsorption and Photocatalysis Process

2007 ◽  
Vol 10 (1) ◽  
Author(s):  
Linda Y. Zou ◽  
Yonggang Luo ◽  
Eric J. Hu
Keyword(s):  
Titanium Dioxide ◽  
Activated Carbon ◽  
Silicon Dioxide ◽  
Crystalline Phase ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Initial Concentration ◽  
Coated Glass ◽  
Surface Areas ◽  
Air Stream

AbstractThree types of titania supported materials including titanium dioxide and silicon dioxide composite, titania-coated activated carbon and titania-coated glass beads were prepared and used as photocatalysts to remove toluene from an air stream. Their surface areas were analysed. TEM image reveals titania-silica composites were nanostructured aggregates. XRD was used to determine their crystalline phase which was 100% anatase for the titania component. A fixed bed reactor was designed and built in the laboratory, the toluene with initial concentration of 300 ppm (1149 mg/m

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.

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