Lanthanum Modified Catalyst for Efficient Supply of Hydrogen through Dehydrogenation of Organic Chemical Hydrides

2011 ◽  
Vol 287-290 ◽  
pp. 2110-2115
Author(s):  
Gang Li Zhu ◽  
Tao Chen ◽  
Xue Dong Jiang ◽  
Hai Liang Zhang ◽  
Bo Lun Yang

Dehydrogenation process of organic chemical hydrides was improved by modifying the catalyst of nickel-activated carbon (Ni/AC) with lanthanum (La). The catalysts were prepared in impregnation method with different amounts of La and Ni. The textural properties and morphology of catalyst were analyzed by nitrogen adsorption and transmission electron microscope equipped with energy dispersive spectrometer respectively. The effects such as metal content and granule size on the dehydrogenation of cyclohexane were investigated in fixed bed reactor. The results show that the metallic active components can be well dispersed on the support, and the elements analysis indicates the metal species tend to assemble on the surface layer rather than being distributed equally in the whole catalyst. The La modified catalyst LaNi/AC exhibited superior catalytic performance to Ni/AC and the conversion was 45% for LaNi/AC catalyst at 673K, while only 34 % for Ni/AC under the same conditions.

Author(s):  
Radwa A. El-Salamony ◽  
Sara A. El-Sharaky ◽  
Seham A. Al-Temtamy ◽  
Ahmed M. Al-Sabagh ◽  
Hamada M. Killa

Abstract Recently, because of the increasing demand for natural gas and the reduction of greenhouse gases, interests have focused on producing synthetic natural gas (SNG), which is suggested as an important future energy carrier. Hydrogenation of CO2, the so-called methanation reaction, is a suitable technique for the fixation of CO2. Nickel supported on yttrium oxide and promoted with cobalt were prepared by the wet-impregnation method respectively and characterized using SBET, XRD, FTIR, XPS, TPR, and HRTEM/EDX. CO2 hydrogenation over the Ni/Y2O3 catalyst was examined and compared with Co–Ni/Y2O3 catalysts, Co% = 10 and 15 wt/wt. The catalytic test was conducted with the use of a fixed-bed reactor under atmospheric pressure. The catalytic performance temperature was 350 °C with a supply of H2:CO2 molar ratio of 4 and a total flow rate of 200 mL/min. The CH4 yield was reached 67%, and CO2 conversion extended 48.5% with CO traces over 10Co–Ni/Y2O3 catalyst. This encourages the direct methanation reaction mechanism. However, the reaction mechanism over Ni/Y2O3 catalyst shows different behaviors rather than that over bi-metal catalysts, whereas the steam reforming of methane reaction was arisen associated with methane consumption besides increase in H2 and CO formation; at the same temperature reaction.


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3347
Author(s):  
Arslan Mazhar ◽  
Asif Hussain Khoja ◽  
Abul Kalam Azad ◽  
Faisal Mushtaq ◽  
Salman Raza Naqvi ◽  
...  

Co/TiO2–MgAl2O4 was investigated in a fixed bed reactor for the dry reforming of methane (DRM) process. Co/TiO2–MgAl2O4 was prepared by modified co-precipitation, followed by the hydrothermal method. The active metal Co was loaded via the wetness impregnation method. The prepared catalyst was characterized by XRD, SEM, TGA, and FTIR. The performance of Co/TiO2–MgAl2O4 for the DRM process was investigated in a reactor with a temperature of 750 °C, a feed ratio (CO2/CH4) of 1, a catalyst loading of 0.5 g, and a feed flow rate of 20 mL min−1. The effect of support interaction with metal and the composite were studied for catalytic activity, the composite showing significantly improved results. Moreover, among the tested Co loadings, 5 wt% Co over the TiO2–MgAl2O4 composite shows the best catalytic performance. The 5%Co/TiO2–MgAl2O4 improved the CH4 and CO2 conversion by up to 70% and 80%, respectively, while the selectivity of H2 and CO improved to 43% and 46.5%, respectively. The achieved H2/CO ratio of 0.9 was due to the excess amount of CO produced because of the higher conversion rate of CO2 and the surface carbon reaction with oxygen species. Furthermore, in a time on stream (TOS) test, the catalyst exhibited 75 h of stability with significant catalytic activity. Catalyst potential lies in catalyst stability and performance results, thus encouraging the further investigation and use of the catalyst for the long-run DRM process.


2009 ◽  
Vol 16 (03) ◽  
pp. 343-349 ◽  
Author(s):  
YUZHOU YING ◽  
KANKA FENG ◽  
ZHIGUO LV ◽  
ZHENMEI GUO ◽  
JINSHENG GAO

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.


Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 752 ◽  
Author(s):  
Yingquan Wu ◽  
Li Tan ◽  
Tao Zhang ◽  
Hongjuan Xie ◽  
Guohui Yang ◽  
...  

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.


2019 ◽  
Vol 15 (1) ◽  
pp. 112-118
Author(s):  
Nastaran Parsafard ◽  
Mohammad Hasan Peyrovi ◽  
Zahra Mohammadian ◽  
Niloofar Atashi

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 


2018 ◽  
Vol 5 (8) ◽  
pp. 180587 ◽  
Author(s):  
Xiaotong Zhang ◽  
Ying Yan

Catalytic combustion of isopropanol in the structured fixed-bed reactor was investigated over Co–ZSM-5 zeolite membrane catalysts. Firstly, ZSM-5 zeolite membrane catalysts with different Si/Al ratios were coated onto the surface of stainless steel fibres via secondary growth method and wet lay-up paper-making method. Then, cobalt oxides were loaded onto the zeolite membranes by impregnation method. The performance of catalytic combustion of isopropanol was conducted over the prepared zeolite membrane catalysts, and the experimental results showed that the catalyst with infinite Si/Al ratio has the highest catalytic activity for the combustion with the lowest T 90 of isopropanol (285°C). Finally, the effects of bed structure, feed concentration, gas hourly space velocity and reaction temperature on the catalytic performance were investigated to analyse the kinetics of isopropanol over the catalyst with infinite Si/Al ratio in the structured fixed-bed reactor. The results showed that the longer residence time could cause higher reaction contact efficiency of isopropanol combustion. T 90 of isopropanol can be dramatically decreased by 105°C in the fixed-bed reactor packed with Co–ZSM-5 zeolite membrane catalysts, compared to the fixed-bed reactor packed with granular catalyst.


2012 ◽  
Vol 457-458 ◽  
pp. 261-264 ◽  
Author(s):  
Zhuo Li ◽  
Cheng Yang ◽  
Jian Qing Li ◽  
Jin Hu Wu

A CuZnAl-based hybrid material was prepared by co-precipitation impregnation method using the active components of methanol synthesis material and pseudo-boehmite as the precursors. The as-prepared material was evaluated for the direct synthesis of dimethyl ether (DME) from syngas in a pressurized continuous flow fixed-bed reactor system. It was revealed that the hybrid material showed high activity and selectivity after an induced period, i.e. the CO conversion and DME selectivity reached as high as 81% and 67%, respectively. Moreover, it was observed that there was only slight carbon which could be eliminated rather than graphite carbon deposited on the material after run for 150 h, indicating its good stability for the direct synthesis process .


2017 ◽  
Vol 23 (2) ◽  
pp. 259-267
Author(s):  
Davarani Hosseini ◽  
Hassan Hashemipour ◽  
Alireza Talebizadeh

In this research, a novel modified wet impregnation method has been successfully developed to synthesize 5% Ni/SiO2 nanocatalyst with high catalytic activity and stability for the partial oxidation of methane. Oleylamine was used as a capping agent in the impregnation solution to improve Ni dispersion and interaction with silica surfaces. The product was analyzed and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, N2 physisorption measurement and transmission electron microscopy (TEM) and temperature- -programmed H2 reduction (H2-TPR). Partial oxidation of methane over the modified catalyst was performed in a continues-flow fixed-bed reactor under atmospheric pressure at 700?C. The modified catalyst showed 91% CH4 conversion, 86% H2 yield and 95% CO selectivity, and these results almost remained constant within 5 h reaction on stream. The excellent catalytic performance of the catalyst was reasonably attributed to the small and uniform distribution of Ni nanoparticles on the support, and structural characterization confirmed this conclusion.


2020 ◽  
Vol 11 (4) ◽  
pp. 11592-11601

In this study, pretreatment conditions such as impregnation time and temperature and drying time and temperature for the production of the iron-cobalt-cerium catalyst with impregnation method as a first step for controlling the synthesis of a new type of three similar metal phase ratio were determined by the Taguchi method. A microtubular fixed bed reactor tested the catalysts' performance under constant conditions according to conversion. The activity and selectivity toward propylene and ethylene have been calculated. The catalyst, which impregnated at 90 °C for 4hr and dried at 120 °C for 24hr, had the best catalytic performance. According to previous studies, the catalyst calcined and the reactor test was performed in the constant and optimum condition such as calcinations in 600 °C for 6hr, reduction with H2 (flow = 30 mL.min-1) for 90 min and P~1atm and also the reaction terms was H2:CO = 1(flow H2 = 37.5 mL.min-1 and CO =37.5 mL.min-1) and p=1bar. Finally, The characterization was done by XRD, SEM, BET, and test on the precursor, optimized catalyst, and optimized catalyst after reactor tests, which all were showed the nanosized catalyst particles.


Author(s):  
Mohd Lukman Musa ◽  
Ramli Mat ◽  
Tuan Amran Tuan Abdullah

Bleaching earth is used to remove colour, phospholipids, oxidized products, metals and residual gums in the palm oil process refinery. Once adsorption process end, the spent bleaching earth (SBE) which contains approximately 20-40 wt. % of the adsorbed oil was usually disposed to landfills. The oil content in SBE was recovered by catalytic cracking using transition metal (Cu, Zn, Cr, and Ni) doped HZSM-5 zeolite in a batch reactor (pyrolysis zone) and fixed bed reactor (catalyst bed). The 5 wt. % of each metallic was introduced in HZSM-5 zeolite using incipient wetness impregnation method. The main objective of this study was to investigate the performance of modified HZSM-5 zeolite for cracking of residual oil in SBE. The physicochemical properties of the catalysts were characterized    using XRD, FTIR, Nitrogen adsorption, and TPD-NH3.  Liquid biofuel obtained from cracking was analyzed by GC-MS. The incorporation of metallic loaded on HZSM-5 zeolite has reduced the surface area of the catalyst that gives a significant impact to the catalytic behavior. The Ni/HZSM-5 zeolite exhibited the highest yields of alkenes as compared to others but slightly decreases the yield of alkanes whereas in contrast with the Cr/HZSM-5, the obtained alkanes were found higher than that of alkenes. In addition, the Cr/HZSM-5 and Ni/HZSM-5 favored the conversion of polycyclic aromatics to mono-aromatics, whereas parent HZSM-5 catalyst favored the formation of poly-aromatics. These results indicated that the metal loaded on HZSM-5 can promote the cracking of heavy fractions to lighter hydrocarbon thus can be used for cracking oil in SBE. Copyright © 2018 BCREC Group. All rights reservedReceived: 10th December 2017; Revised: 31st May 2018; Accepted: 10th June 2018How to Cite: Musa, M.L., Mat, R., Abdullah, T.A.T. (2018). Catalytic Conversion of Residual Palm Oil in Spent Bleaching Earth (SBE) By HZSM-5 Zeolite based-Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (3): 456-465 (doi:10.9767/bcrec.13.3.1929.456-465)Permalink/DOI: https://doi.org/10.9767/bcrec.13.3.1929.456-465 


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