scholarly journals CO2 Reforming of CH4 on Co-Containing Supported Catalysts

2016 ◽  
Vol 2 (1) ◽  
pp. 41 ◽  
Author(s):  
Sh.S. Itkulova ◽  
K.Z. Zhunusova ◽  
I.S. Chanycheva ◽  
G.D. Zakumbaeva
Keyword(s):  
Carbon Dioxide ◽  
Bimetallic Catalysts ◽  
Supported Catalysts ◽  
Coke Formation ◽  
Carbon Oxide ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Reaction Products ◽  
Co2 Reforming ◽  
Co2 Reforming Of Ch4

<p>Mono- and bimetallic cobalt-containing catalysts supported on alumina have been investigated in the reaction of interaction between carbon dioxide and methane at variation of experiment temperature and pressure. It was shown, that the bimetallic catalysts have a high activity in this reaction in compare with monometallic ones. The main reaction products are carbon oxide, hydrogen, water and oxygenates. The yield of latter reaches 30% at certain conditions (P &gt; 0.5 MPa, T &lt; 853K). The maximum conversion of both methane (100%) and carbon dioxide (94%) is reached at lower pressure (0.1MPa) and 1023 K. In these conditions the synthesis-gas is a main reaction product. One of the advantages of the bimetallic catalysts is their resistance to coke formation.</p>

scholarly journals Chemical Denitrification with Mg0 Particles in Column Systems

2020 ◽  
Vol 12 (7) ◽  
pp. 2984 ◽  
Author(s):  
Alessio Siciliano ◽  
Giulia Maria Curcio ◽  
Carlo Limonti
Keyword(s):  
Kinetic Constant ◽  
Operating Parameter ◽  
Process Efficiency ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Reaction Products ◽  
Metallic Elements ◽  
Reactive Material ◽  
Maximum Reaction Rate ◽  
Maximum Reaction

The removal of nitrate from aqueous environments through zero-valent metallic elements is an attractive technique that has gained increasing interest in recent years. In comparison to other metallic elements, zero-valent magnesium (ZVM) has numerous beneficial aspects. Nevertheless, the use of Mg0 particles for nitrate reduction in column systems has not been investigated yet. To overcome the lack of research, in the present study, a wide experimental activity was carried out to develop a chemical denitrification process through ZVM in batch column equipment. Several tests were executed to evaluate the effects of recirculation hydraulic velocity, pH, Mg0 amount, N-NO3− initial concentration and temperature on the process performance. The results show that the process efficiency is positively influenced by the recirculation velocity increase. In particular, the optimal condition was detected with a value of 1 m/min. The process pH was identified as the main operating parameter. At pH 3, abatements higher than 86.6% were reached for every initial nitrate concentration tested. In these conditions, nitrogen gas was detected as the main reaction product. The pH increase up to values of 5 and 7 caused a drastic denitrification decline with observed efficiencies below 26%. At pH 3, the ratio (RMN) between Mg0 and initial nitrate amount also plays a key role in the treatment performance. A characteristic value of about RMN = 0.333 gMg0/mgN-NO3− was found with which it is possible to reach the maximum reaction rate. Unexpectedly, the process was negatively affected by the increase in temperature from 20 to 40 °C. At 20 °C, the material showed satisfactory denitrification efficiencies in subsequent reuse cycles. With the optimal RMN ratio, removals up to 90% were detected by reusing the reactive material three times. By means of a kinetic analysis, a mathematical law able to describe the nitrate abatement curves was defined. Moreover, the relation between the observed kinetic constant and the operating parameters was recognized. Finally, the reaction pathways were proposed and the corrosion reaction products formed during the treatment were identified.

Coke formation during CO2 reforming of CH4 over alumina-supported nickel catalysts

2009 ◽  
Vol 364 (1-2) ◽  
pp. 150-155 ◽  
Author(s):  
A.S.A. Al–Fatish ◽  
A.A. Ibrahim ◽  
A.H. Fakeeha ◽  
M.A. Soliman ◽  
M.R.H. Siddiqui ◽  
...  
Keyword(s):  
Coke Formation ◽  
Nickel Catalysts ◽  
Co2 Reforming ◽  
Co2 Reforming Of Ch4 ◽  
Supported Nickel Catalysts

scholarly journals Characterization of Tribofilm from Sulfurized Mohwa Oil

2011 ◽  
Vol 2011 ◽  
pp. 1-12
Author(s):  
Arun Kumar Singh
Keyword(s):  
Surface Characterization ◽  
Iron Sulfide ◽  
Analysis Data ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Iron Sulfides ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
Load Carrying

The reaction products of sulfurized Mohwa oil with iron powder in hydrocarbon medium at 150°C for 8 h were studied to investigate the type of lubricant films formed during their application as antiwear and extreme pressure additives. The main reaction product was isolated on the basis of its solubility in mixed solvent. Surface characterization was carried out using ultraviolet-visible spectroscopy (UV), fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), X-ray diffraction spectroscopy (XRD), scanning electron microscope (SEM), and high frequency reciprocal rig (HFRR). An examination of their elemental analysis and instrumental analysis data reveals that there is reduction in the length of the alkyl chains and carbonyl ester groups with formation of inorganic iron sulfides. Polymerized product with a number of ketonic and aldehydic groups containing iron and sulfur in the polymeric films in the form of unsaturated cyclic rings was also formed. The films are organo-inorganic in nature, unlike the purely inorganic iron sulfide type. The load-carrying characteristic of this product is strongly influenced by the type of the film formed on the iron surfaces.

Ordered mesoporous CoO-NiO-Al2O3 bimetallic catalysts with dual confinement effects for CO2 reforming of CH4

2017 ◽  
Vol 281 ◽  
pp. 241-249 ◽  
Author(s):  
Xin Huang ◽  
Changchun Ji ◽  
Changzhen Wang ◽  
Fukui Xiao ◽  
Ning Zhao ◽  
...  
Keyword(s):  
Bimetallic Catalysts ◽  
Confinement Effects ◽  
Co2 Reforming ◽  
Co2 Reforming Of Ch4 ◽  
Ordered Mesoporous

scholarly journals The Effect of ZrO2 as Different Components of Ni-Based Catalysts for CO2 Reforming of Methane and Combined Steam and CO2 Reforming of Methane on Catalytic Performance with Coke Formation

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 984
Author(s):  
Wassachol Sumarasingha ◽  
Somsak Supasitmongkol ◽  
Monrudee Phongaksorn
Keyword(s):  
Oxygen Transfer ◽  
Supported Catalysts ◽  
Coke Formation ◽  
Ni Catalyst ◽  
Impregnation Method ◽  
Co2 Conversion ◽  
Spent Catalyst ◽  
Zro2 Content ◽  
Co2 Reforming ◽  
Co2 Reforming Of Methane

The role of ZrO2 as different components in Ni-based catalysts for CO2 reforming of methane (CRM) has been investigated. The 10 wt.% Ni supported catalysts were prepared with ZrO2 as a support using a co-impregnation method. As a promoter (1 wt.% ZrO2) and a coactive component (10 wt.% ZrO2), the catalysts with ZrO2 were synthesized using a co-impregnation method. To evaluate the effect of the interaction, the Ni catalyst with ZrO2 as a coactive component was prepared by a sequential impregnation method. The results revealed that the activity, the selectivity, and the anti-coking ability of the catalyst depend upon the ZrO2 content, the Ni-ZrO2 interaction, basicity, and oxygen mobility of each catalyst resulting in different Ni dispersion and oxygen transfer pathway from ZrO2 to Ni. According to the characterization and catalytic activation results, the Ni catalyst with low ZrO2 content (as a promoter) presented highest selectivity toward CO owning to the high number of weak and moderate basic sites that enhance the CO2 activation-dissociation. The lowest activity (CH4 conversion ≈ 40% and CO2 conversion ≈ 39%) with the relatively high quantity of total coke formation (the weight loss of the spent catalyst in TGA curve ≈ 22%) of the Ni catalyst with ZrO2 as a support is ascribed to the lowest Ni dispersion due to the poor Ni-ZrO2 interaction and less oxygen transfer from ZrO2 to the deposited carbon on the Ni surface. The effect of a poor Ni-ZrO2 interaction on the catalytic activity was deducted by decreasing ZrO2 content to 10 wt.% (as a coactive component) and 1 wt.% (as a promoter). Although Ni catalysts with 1 wt.% and 10 wt.% ZrO2 provided similar oxygen mobility, the lack of oxygen transfer to coke during CRM process on the Ni surface was still indicated by the growth of carbon filament when the catalyst was prepared by co-impregnation method. When the catalyst was prepared by a sequential impregnation, the intimate interaction of Ni and ZrO2 for oxygen transfer was successfully developed through a ZrO2-Al2O3 composite. The interaction in this catalyst enhanced the catalytic activity (CH4 conversion ≈ 54% and CO2 conversion ≈ 50%) and the oxygen transport for carbon oxidation (the weight loss of the spent catalyst in TGA curve ≈ 7%) for CRM process. The Ni supported catalysts with ZrO2 as a promoter prepared by co-impregnation and with ZrO2 as a coactive component prepared by a sequential impregnation were tested in combined steam and CO2 reforming of methane (CSCRM). The results revealed that the ZrO2 promoter provided a greater carbon resistance (coke = 1.213 mmol·g−1) with the subtraction of CH4 and CO2 activities (CH4 conversion ≈ 28% and CO2 conversion ≈ %) due to the loss of active sites to the H2O activation-dissociation. Thus, the H2O activation-dissociation was promoted more efficiently on the basic sites than on the vacancy sites in CSCRM.

Role of Energy Dissipation and Surface Mobility in Heterogeneous Catalysis by Metals

1998 ◽  
Vol 63 (11) ◽  
pp. 1851-1868 ◽  
Author(s):  
Zlatko Knor ◽  
Jan Plšek
Keyword(s):  
Energy Dissipation ◽  
Gas Phase ◽  
Bimetallic Catalysts ◽  
Supported Catalysts ◽  
Bound State ◽  
Reaction Products ◽  
Atomic Steps ◽  
Surface Mobility ◽  
Species Mobility

The fundamental role of excess energy dissipation and of surface species mobility, both in the preparation of model metallic catalysts (bimetallic catalysts, bimetallic oxide-supported catalysts), and in the activation of reactant molecules on the catalyst surfaces (single crystals, bimetallic and bimetallic oxide-supported catalysts) are discussed. A generalized model of surface interactions is proposed which satisfactorily explains the trapping of particles from the gas phase at the atomic steps and recovery of the trapping sites due to migration of the trapped species towards flat terraces. Higher probability of encounter of these species with other reactants on flat terraces and easier desorption of the reaction products from there in comparison with the bound state at the edges of atomic steps can be expected. Results of FIM and FEM studies of Pt, Dy-W, Pd-W and Pd-Mo systems are used to illustrate selected features of the proposed general model.

scholarly journals Nanosized Ni/SBA-15 Catalysts for CO2 Reforming of CH4

2019 ◽  
Vol 9 (9) ◽  
pp. 1926 ◽  
Author(s):  
Ahmed A. Ibrahim ◽  
Ashraf Amin ◽  
Ahmed S. Al-Fatesh ◽  
Nadavala Siva Kumar ◽  
Samsudeen Olajide Kasim ◽  
...  
Keyword(s):  
Bimetallic Catalysts ◽  
Catalytic Properties ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Dry Reforming ◽  
Fixed Bed Reactor ◽  
Co2 Reforming ◽  
Methane Dry Reforming ◽  
Remarkable Effect ◽  
Co2 Reforming Of Ch4

Ni, Co, and Co–Ni bimetallic catalysts supported over SBA-15 and over SBA-15 doped with Zn or Ce oxides were prepared and tested in a methane dry reforming reaction. The loading of the metals in the catalyst was 5 wt % for either mono or bimetallic catalysts. The prepared catalysts were tested in a continuous-flow fixed-bed reactor at 800 °C under atmospheric pressure. XRD, TPR, TPD, and SEM characterization techniques were employed to investigate the catalytic properties of fresh catalysts. SEM and TGA were used to study the catalytic properties of spent catalysts. A remarkable effect on the reduction properties and catalytic performance of catalysts was observed after adding Zn and Ce. Over an 8 h test, Ni/SBA-15 showed the best activity and stability. The conversion was 90% for CH4 and CO2. Co–Ni/SBA-15 and Co–Ni/Ce–SBA-15 have shown a reasonable activity and stability. Selectivity of the Ni/SBA-15 catalyst was higher than all other catalysts as indicated by the H2/CO ratio. Co/SBA-15 and Co–Ni/Zn–SBA-15 showed a low activity and selectivity. TPD–NH3 profiles indicated that doping SBA-15 with Ce and/or Zn increased the catalyst acidic sites. Ni/SBA-15 is an excellent potential catalyst for commercial methane dry reforming processes.

Determination of deoxynivalenol sulphonates in cereal samples: method development, validation and application

2014 ◽  
Vol 7 (3) ◽  
pp. 233-245 ◽  
Author(s):  
H.E. Schwartz-Zimmermann ◽  
M. Paulick ◽  
S. Dänicke ◽  
D. Schatzmayr ◽  
F. Berthiller
Keyword(s):  
Thermal Treatment ◽  
Moisture Content ◽  
Method Development ◽  
Matrix Effects ◽  
Main Reaction ◽  
Prolonged Storage ◽  
Main Reaction Product ◽  
Reagent Concentration ◽  
Reaction Products

The first short and simple RP-UHPLC-MS/MS based method for co-determination of the Fusarium mycotoxin deoxynivalenol (DON) and its reaction products upon treatment with sulphur reagents, the DON sulphonates (DONS) 1, 2 and 3, in cereals was developed and validated. Recoveries of extraction from maize, wheat and barley were between 88 and 107%. Matrix effects ranging between 93 and 234% in concentrated extracts and between 99 and 134% in diluted extracts were compensated by quantitation against matrix matched standards. Measurement of concentrated and diluted extracts enabled determination of DONS-1, -2, -3 and DON in cereals in a concentration range from 0.015 to 120 mg/kg. The method was then applied to investigate the influence of reagent concentration, type of sulphur reagent, moisture content, presence of propionic acid, storage time and thermal treatment in the presence of sodium metabisulphite (SBS) and monomethylamine (MMA) on DON reduction and DONS formation. DON reduction greater than 80% was obtained in several experiments and required storage at moisture contents between 25 and 30% (at reagent concentration of 0.5%) for less than one week, storage with 0.5% SBS at 14% moisture for 6 weeks or thermal treatment in the presence of SBS and MMA. The efficiency of sodium sulphite for DON reduction was systematically compared with that of SBS and found to be lower at 14% moisture content, but similar at 30% moisture. Under most storage conditions, DONS-3 was the main reaction product, followed by DONS-2. Prolonged storage for more than 6-8 weeks shifted the pattern of formed DON sulphonates towards DONS-2. Likewise, thermal treatment in the presence of SBS and MMA caused exclusive formation of DONS-1 and -2. Due to partial degradation of DONS-3 to DON under physiological conditions, predominant conversion of DON into DONS-1 and DONS-2 is desirable.

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