scholarly journals Enhanced Ni-Al-Based Catalysts and Influence of Aromatic Hydrocarbon for Autothermal Reforming of Diesel Surrogate Fuel

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 573 ◽  
Author(s):  
Dong Geon Ju ◽  
Seong Bin Jo ◽  
Dong Su Ha ◽  
Tae Young Kim ◽  
Suk Yong Jung ◽  
...  
Keyword(s):  
Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbons ◽  
Diesel Fuel ◽  
Carbon Deposition ◽  
Autothermal Reforming ◽  
Sulfur Poisoning ◽  
Impregnation Method ◽  
X Ray ◽  
Surrogate Fuel ◽  
Catalytic Performances

Aromatic hydrocarbons along with sulfur compounds in diesel fuel pose a significant threat to catalytic performances, due mainly to carbon deposition on the catalytic surface. In order to investigate the influence of an aromatic hydrocarbon on the autothermal reforming of diesel fuel, 1-methylnaphthalene (C11H10) was selected as an aromatic hydrocarbon. Two types of diesel surrogate fuel, i.e., DH (dodecane (C12H26) and hexadecane (C16H34) mixture) as well as DHM (DH fuel and C11H10 mixture) fuel, were prepared. A Rh-Al-based catalyst (R5A-I) was prepared using a conventional impregnation method. Various Ni-Al-based catalysts with Fe and Rh promoters were prepared via a polymer modified incipient method to improve the carbon coking resistance. These catalysts were tested under conditions of S/C = 1.17, O2/C = 0.24, 750 °C, and GHSV = 12,000 h-1 at DH or DHM fuel. R5A-I exhibited excellent catalytic performance in both DH and DHM fuels. However, carbon coking and sulfur poisoning resistance were observed in our previous study for the Ni-Al-based catalyst with the Fe promoter, which became deactivated with increasing reaction time at the DHM fuel. In the case of the Rh promoter addition to the Ni-Al-based catalysts, the catalytic performances decreased relatively slowly with increasing (from 1 wt.% (R1N50A) to 2 wt.% (R2N50A)) content of Rh2O3 at DHM fuel. The catalysts were analyzed via scanning electron microscopy combined with energy dispersive X-ray, X-ray diffraction, and X-ray photoelectron spectroscopy. Gas chromatography-mass spectrometry detected various types of hydrocarbons, e.g., ethylene (C2H4), with catalyst deactivation. The results revealed that, among the produced hydrocarbons, C2H4 played a major role in accelerating carbon deposition that blocks the reforming reaction. Therefore, Rh metal deserves consideration as a carbon coking inhibitor that prevents the negative effects of the C2H4 for autothermal reforming of diesel fuel in the presence of aromatic hydrocarbons.

Deactivation of Ni–Al-Based Catalysts for Autothermal Reforming of Diesel Surrogate Fuel in the Presence of an Aromatic Hydrocarbon

2020 ◽  
Vol 20 (11) ◽  
pp. 7018-7026
Author(s):  
Dong-Geon Ju ◽  
Seong-Bin Jo ◽  
Dong-Su Ha ◽  
Tae-Young Kim ◽  
Suk-Yong Jung ◽  
...  
Keyword(s):  
Aromatic Hydrocarbon ◽  
Diesel Fuel ◽  
Photoelectron Spectroscopy ◽  
Catalyst Deactivation ◽  
Catalytic Performance ◽  
Autothermal Reforming ◽  
Gas Chromatography Mass Spectrometry ◽  
X Ray ◽  
Bet Analysis ◽  
Surrogate Fuel

Diesel fuel can produce higher concentrations of H2 and CO gases than other types of hydrocarbon fuels via a reforming reaction for solid oxide fuel cells (SOFCs). However, in addition to sulfur compounds and aromatic hydrocarbons in diesel fuel are a major cause of catalyst deactivation. To elucidate the phenomenon of catalyst deactivation in the presence of an aromatic hydrocarbon, dodecane (C12H26) and hexadecane (C16H34) were blended with an aromatic hydrocarbon such as 1-methylnaphthalene (C11H10) to obtain a diesel surrogate fuel. The experiments were performed for autothermal reforming of the diesel surrogate fuel under conditions of S/C = 1.17, O2/C = 0.24, 750°C and GHSV= 12,000 h−1. Three Ni–Al-based catalysts with 10 wt% (N10A), 30 wt% (N30A) and 50 wt% (N50A) of NiO were prepared via the polymer modified incipient method. Whereas all of the Ni–Al-based catalysts were deactivated with increasing reaction time, the catalysts with greater Ni contents tended to maintain their catalytic performance for a longer time. Correlation between the catalytic performances and Ni content were analyzed by temperature-programmed reduction (TPR), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope with energy-dispersive X-ray spectroscopy (SEM-EDX), Brunauer-Emmett-Teller(BET) analysis, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Also, we concluded that ethylene (C2H4), which was detected by gas chromatography-mass spectrometry (GC-MS), was the fundamental cause of deactivation of the Ni–Al-based catalysts by accelerating the deposition of wire-type carbon on the catalytic surface.

Bestimmung von innermolekularen Torsionswinkeln aus Hyperfeinstruktur-Aufspaltungen und g-Faktoren

1965 ◽  
Vol 20 (9) ◽  
pp. 1117-1121 ◽  
Author(s):  
K. Möbius
Keyword(s):  
Electron Diffraction ◽  
Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbons ◽  
Small Amplitude ◽  
Membered Ring ◽  
Radical Ions ◽  
Hydrogen Atoms ◽  
Stereochemical Structure ◽  
X Ray ◽  
Phenyl Rings

The stereochemical structure of aromatic hydrocarbons in solution being overcrowded with hydrogen atoms is not known with certainty, because the conventional X-ray and electron diffraction methods are suitable only for samples in the crystalline and vapor phase. Using EPR spectroscopy for the aromatic hydrocarbon radicals biphenyl (—), phenanthrene (—) and pentaphenylcyclopentadienyl (PPCPD) innermolecular twist and bond angles could be determined by means of hfssplittings and g-factors. Stably solvated biphenyl radical ions are found to have twist angles of 38 ±2°; phenanthrene ions turn out to be planar but change their angles of hybridization at particular positions; in the PPCPD radical the phenyl rings oscillate with small amplitude around planes orthogonal to the five-membered ring.

Promotion Effects of La2O3 on Ni/Al2O3 Catalysts for CO2 Methanation

2015 ◽  
Vol 1118 ◽  
pp. 205-210 ◽  
Author(s):  
Wei Chang Chen ◽  
Wen Yang ◽  
Jian Dong Xing ◽  
Lei Liu ◽  
Hong Li Sun ◽  
...  
Keyword(s):  
Particle Size ◽  
Impregnation Method ◽  
Temperature Programmed Reduction ◽  
Active Components ◽  
X Ray ◽  
Induce Effect ◽  
Temperature Programmed ◽  
Ni Species ◽  
Adsorption Desorption ◽  
Catalytic Performances

Ni/Al2O3catalysts improved with different La contents were prepared by the conventional co-impregnation method and characterized by X-ray powder diffraction (XRD), N2adsorption-desorption, H2temperature-programmed reduction (H2-TPR). Catalytic performances for CO2methanation under condition (CO2/H2=4.1:1, 1 atm) were discussed in detail. XRD result demonstrated that the addition of La was in favor of decreasing the Ni particle size and increasing the dispersion of Ni species. The H2-TPR showed that La can change the proportion of various Ni species and increase the content of easily reducible Ni species. These results indicate that La species induce effect, resulting in smaller particle size and weaker interaction between active components and the support, higher dispersions, and reducibility of active phases, ultimately improving catalytic activity of CO2methanation.

scholarly journals The characterization of NiO-CoO/MgO catalyst for autothermal reforming of methane

2018 ◽  
Vol 4 (2) ◽  
pp. 191
Author(s):  
Tutuk Djoko Kusworo ◽  
A R Songip ◽  
N A. Saidina Amin
Keyword(s):  
Steam Reforming ◽  
Coke Formation ◽  
Autothermal Reforming ◽  
Impregnation Method ◽  
Carbon Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Tga Analysis

The characterization of NiO-CoO/MgO catalyst for autothermal reforming of methaneThe drawback of conventional reforming of methane such as partial oxidation and steam reforming was carbon formation. The research was developed a suitable catalyst for combination of partial and steam reforming of methane and called autothermal reforming to reduce the coke formation. The NiO-CoO/MgO catalysts were prepared by an impregnation method and characterized by Temperature Programmed Reduction (TPR), X-ray Diffraction (XRD) and Thermal Gravitymetry Analysis (TGA). The TPR and XRD results reveal that the catalyst characteristic is strongly influenced by the Co/Ni ratio. From TPR and TGA analysis, the sintering phenomena did not occur in the autothermal reforming of methane. The results reveal that Co/Ni ratios have a small effect in the catalytic activity for autothermal reforming. Nevertheless, the catalyst showed an optimum performance in this process when its Co/Ni ratio was 0.75. Keywords: Autothermal ReformingAbstrakMasalah yang terjadi pada proses konvensional reformasi metana seperti oksidasi parsial metana dan reformasi kukus adalah pembentukan karbon. Penelitian yang dilakukan adalah mengembangkan katalis yang sesuai untuk gabungan proses oksidasi parsial dan reformasi kukus atau yang disebut reformasi metana secara autothermal. Katalis NiO-CoO/MgO yang digunakan dibuat dengan metode impregnasi dan dilakukan pengujian dengan TPR, XRD dan TGA untuk mengetahui sifat-sifat dari katalis tersebut. Hasil TPR dan XRD menunjukkan bahwa karakteristik dari katalis sangat dipengaruhi oleh perbandingan CoiN i. Hasil pengamatan TPR dan TGA menunjukan bahwa sintering tidak terjadi di dalam proses reformasi metana secara autothermal. Hasil eksperimen juga menunjukan bahwa perbandingan Co/Ni hanya kecil pengaruhnya pada unjuk kerja katalis. Namun demikian katalis menunjukan unjuk kerja yang optimum pada perbandingan CoiN i = 0.75. Kata Kunci: Reformasi Autothermal

scholarly journals CATALYTIC PERFORMANCES OF Fe2O3/TS-1 CATALYST IN PHENOL HYDROXYLATION REACTION

2010 ◽  
Vol 10 (2) ◽  
pp. 149-155 ◽  
Author(s):  
Didik Prasetyoko ◽  
Cholifah Endah Royani ◽  
Hamzah Fansuri ◽  
Zainab Ramli ◽  
Hadi Nur
Keyword(s):  
Reaction Rate ◽  
Formation Rate ◽  
Nitrogen Adsorption ◽  
Industrial Applications ◽  
Phenol Hydroxylation ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydroxylation Reaction ◽  
Catalytic Performances

Hydroxylation reaction of phenol into diphenol, such as hydroquinone and catechol, has a great role in many industrial applications. Phenol hydroxylation reaction can be carried out using Titanium Silicalite-1 (TS-1) as catalyst and H2O2 as an oxidant. TS-1 catalyst shows high activity and selectivity for phenol hydroxylation reaction. However, its hydrophobic sites lead to slow H2O2 adsorption toward the active site of TS-1. Consequently, the reaction rate of phenol hydroxylation reaction is tends to be low. Addition of metal oxide Fe2O3 enhanced hydrophilicity of TS-1 catalyst. Liquid phase catalytic phenol hydroxylation using hydrogen peroxide as oxidant was carried out over iron (III) oxide-modified TS-1 catalyst (Fe2O3/TS-1), that were prepared by impregnation method using iron (III) nitrate as precursor and characterized by X-ray diffraction, infrared spectroscopy, nitrogen adsorption, pyridine adsorption, and hydrophilicity techniques. Catalysts 1Fe2O3/TS-1 showed maximum catalytic activity of hydroquinone product. In this research, the increase of hydroquinone formation rate is due to the higher hydrophilicity of Fe2O3/TS-1 catalysts compare to the parent catalyst, TS-1.   Keywords: Fe2O3/TS-1, hydrophilic site, phenol hydroxylation

Supported Ni catalyst made by electroless Ni-B plating for diesel autothermal reforming

2012 ◽  
Vol 1446 ◽  
Author(s):  
Zetao Xia ◽  
Liang Hong ◽  
Wei Wang ◽  
Zhaolin Liu
Keyword(s):  
Critical Role ◽  
Autothermal Reforming ◽  
Sulfur Poisoning ◽  
Nano Particles ◽  
Ni Catalyst ◽  
Impregnation Method ◽  
Catalytic Systems ◽  
Organic Precursor ◽  
Supported Ni Catalyst ◽  
Supported Ni

ABSTRACTCexGd1-xO2-δ (CGO)-supported Ni nano grains were prepared initially by electrolessly depositing Ni-B alloy nano particles onto an activated carbon (AC). The as-deposited Ni-B particles were then transferred from AC to CGO through the metallo-organic precursor approach. The resultant Ni/CGO catalysts displayed excellent catalytic activity and chemical stability against coking and sulfur poisoning in catalyzing autothermal reforming (ATR) of a surrogate diesel fuel, comprising dodecane, tetralin and a substituted thiophene. For comparison purpose, a Ni/CGO catalyst prepared by the conventional impregnation method was employed in the same ATR system. These two catalytic systems exhibited rather discrepant outcomes. It was found that the Ni(B)/CGO catalyst was capable of repressing selectivity of ethylene during the reforming process. In addition to this, CGO played a critical role in thermal cracking hydrocarbon chains and inhibiting sulfur poisoning.

1,1’-Biaceanthrylene and 2,2'-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Model Systems ◽  
Redox Potentials ◽  
Dimer Model ◽  
Optical And Electronic Properties ◽  
Polycyclic Aromatic

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>

1,1’-Biaceanthrylene and 2,2'-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Model Systems ◽  
Redox Potentials ◽  
Dimer Model ◽  
Optical And Electronic Properties ◽  
Polycyclic Aromatic

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>

Structural/Texture Evolution During Facile Substitution of Ni into ZSM-5 Nanostructure vs. its Impregnation Dispersion Used in Selective Transformation of Methanol to Ethylene and Propylene

2020 ◽  
Vol 23 ◽  
Author(s):  
Parisa Sadeghpour ◽  
Mohammad Haghighi ◽  
Mehrdad Esmaeili
Keyword(s):  
High Temperature ◽  
Physicochemical Properties ◽  
Active Sites ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Light Olefins ◽  
Isomorphous Substitution ◽  
Impregnation Method ◽  
Hydrothermal Temperature ◽  
X Ray

Aim and Objective: Effect of two different modification methods for introducing Ni into ZSM-5 framework was investigated under high temperature synthesis conditions. The nickel successfully introduced into the MFI structures at different crystallization conditions to enhance the physicochemical properties and catalytic performance. Materials and Methods: A series of impregnated Ni/ZSM-5 and isomorphous substituted NiZSM-5 nanostructure catalysts were prepared hydrothermally at different high temperatures and within short times. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray (EDX), Brunner, Emmett and Teller-Barrett, Joyner and Halenda (BET-BJH), Fourier transform infrared (FTIR) and Temperature-programmed desorption of ammonia (TPDNH3) were applied to investigate the physicochemical properties. Results: Although all the catalysts showed pure silica MFI–type nanosheets and coffin-like morphology, using the isomorphous substitution for Ni incorporation into the ZSM-5 framework led to the formation of materials with lower crystallinity, higher pore volume and stronger acidity compared to using impregnation method. Moreover, it was found that raising the hydrothermal temperature increased the crystallinity and enhanced more uniform incorporation of Ni atoms in the crystalline structure of catalysts. TPD-NH3 analysis demonstrated that high crystallization temperature and short crystallization time of NiZSM-5(350-0.5) resulted in fewer weak acid sites and medium acid strength. The MTO catalytic performance was tested in a fixed bed reactor at 460ºC and GHSV=10500 cm3 /gcat.h. A slightly different reaction pathway was proposed for the production of light olefins over impregnated Ni/ZSM-5 catalysts based on the role of NiO species. The enhanced methanol conversion for isomorphous substituted NiZSM-5 catalysts could be related to the most accessible active sites located inside the pores. Conclusion: The impregnated Ni/ZSM-5 catalyst prepared at low hydrothermal temperature showed the best catalytic performance, while the isomorphous substituted NiZSM-5 prepared at high temperature was found to be the active molecular sieve regarding the stability performance.

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