Studying the efficiency of the diesel fuel isodewaxing process on a zeolite-containing nickel–molybdenum catalyst

A GIP-14 diesel fuel isodewaxing catalyst based on a mixture of zeolites with different pore structures and entrance sizes and transition metals Ni and Mo as hydrogenating components is developed. Its stability during operation is studied. It is shown that the cold filter plugging point (CFPP) of the diesel fuel reaches values below–38°C at its yield of 92–93 wt %, temperatures of 305–310°C, and a feedstock hourly space velocity (FHSV) of 3 h^?1. A pilot diesel fuel sample is tested according to GOST (Russian State Standard) R 55475–2013. Comparative tests of domestic and foreign catalysts show that the developed GIP-14 catalyst conforms to international standards and allows the production of diesel fuel with required cold flow properties under milder conditions (300°C against 320–325°C for the foreign catalyst) at a higher FHSV (3 h^?1 against 2 h^?1). The production of GIP-14 catalyst is planned to be launched in 2017.     

Anion-modified zirconia: effect of metal promotion and hydrogen reduction on hydroisomerization of n-hexadecane and Fischer–Tropsch waxes

The effect of metal promoters on the activity and selectivity of tungstated zirconia (8 wt.% W) for n-hexadecane isomerization in a trickle bed continuous reactor is studied by using different metals (Pt, Ni, and Pd) and, in one case, by varying metal loading. Platinum is found to be the best promoter. The effect of hydrogen reduction is investigated using platinum-promoted tungstated zirconia catalysts (Pt/WO₃/ZrO₂, 0.5 wt.% Pt and 6.5 wt.% W). Pretreatment at temperatures between 300 and 400°C for 3 h in hydrogen is found to be slightly beneficial for achieving high yields of isohexadecane. A platinum promoted sulfated zirconia (Pt/SO₄/ZrO₂) is compared with a Pt/WO₃/ZrO₂ catalyst for the hydroisomerization of n-hexadecane in the same reactor at the same n-hexadecane conversion. The former is a good cracking catalyst and the latter is suitable for use as a hydroisomerization catalyst. In a 27-ml microautoclave reactor, studies of the hydroisomerization and hydrocracking of two Fischer–Tropsch (F–T) wax samples are carried out. Severe cracking can be effectively suppressed using a Pt/WO₃/ZrO₂ catalyst so as to obtain branched isomers in the diesel fuel or lube-base oil range.     

Hydrocracking of vegetable oil on boron-containing catalysts: Effect of the nature and content of a hydrogenation component

Catalysts based on metals (Pt, Pd) and metal oxides (NiO, Co₃O₄, MoO₃, WO₃), supported on the surface of borate-containing aluminum oxide (B₂O₃–Al₂O₃), in the hydrocracking of sunflower oil at a temperature of 400°C, a pressure 4.0 MPa and a mass hourly space velocity MHSV 5.0 h^–1 are compared. H₂ TPR and IR spectroscopy of adsorbed CO and ESDR show that the hydrogenation catalyst components are Pt⁰ and Pd⁰, a mixture of Ni²⁺ + Ni⁰, Co²⁺ + Co⁰, or a mixture of the highest and partially reduced oxides of Mo and W. It is established that catalysts containing Pt, Pd, NiO and Co₃O₄, ensure complete oil hydrodeoxygenation. The main oxygen removal reactions in Ptand Pd-systems are decarboxylation and hydrodecarbonylation. For catalysts with NiO and Co₃O₄, characteristic reactions are reduction and methanation. The highest yield of the diesel fraction was obtained on Pt/B₂O₃-Al₂O₃ catalysts with metal contents of 0.3–1.0 wt %. Along with n-alkanes, the diesel fractions obtained on these catalysts include cycloalkanes and iso-alkanes (up to around 40 wt %) and aromatic hydrocarbons present in trace amounts. Hydrocracking on the Pt system at 400°C for 20 h with MHSV of 1.0 h^–1 produces a diesel fraction with a yield of at least 82.0 wt % and the content of iso-alkanes at least 76.1 wt %.     

Formic acid oxidation by carbon-supported palladium catalysts in direct formic acid fuel cell

The oxidation of formic acid by the palladium catalysts supported on carbon with high surface area was investigated. Pd/C catalysts were prepared by using the impregnation method. 30 wt% and 50 wt% Pd/C catalysts had a high BET surface area of 123.7 m²/g and 89.9 m²/g, respectively. The fuel cell performance was investigated by changing various parameters such as anode catalyst types, oxidation gases and operating temperature. Pd/C anode catalysts had a significant effect on the direct formic acid fuel cell (DFAFC) performance. DFAFC with Pd/C anode catalyst showed high open circuit potential (OCP) of about 0.84 V and high power density at room temperature. The fuel cell with 50 wt% Pd/C anode catalyst using air as an oxidant showed the maximum power density of 99 mW/cm². On the other hand, a fuel cell with 50 wt% Pd/C anode catalyst using oxygen as an oxidant showed a maximum power density of 163 mW/cm² and the maximum current density of 590 mA/cm² at 60 °C.     

Investigation the Effect of Oxygenic Compounds on the Isomerization of Bioparaffins Over Pt/SAPO-11

The production of gas oil blending components which a new application of the Pt/SAPO-11 is introduced, while the effect of oxygenic compounds on the isomerization of paraffin mixtures is highlighted. The experiments were carried out on 0.5% Pt/SAPO-11 catalyst at 300?C380 °C, 30?C80 bar, liquid hourly space velocity = 0.75?C2.0 h^?1 and H₂/hydrocarbon ratio = 400 Nm³/m³, while 0.25?C5.0% oleic acid was added to the feedstock. At the favourable operational parameters the isoparaffins concentration of the products (cetane number: 78?C86, cold filter plugging point: between ?19 and ?10 °C) reached 65?C72%, if the oleic acid content of the feedstock was lower than 0.5%. These isomer contents were significantly decreased by increasing the oleic acid content of the feedstock.     

Plasma-assisted ammonia decomposition over Fe–Ni alloy catalysts for CO x-Free hydrogen

On-site ammonia (NH₃) decomposition is considered as a potential path to supply CO _x-free hydrogen for fuel cell vehicles. In this article, monometallic catalysts (Fe, Co, Ni, and Mo) and bimetallic catalysts (Fe–Co, Mo–Co, Fe–Ni, and Mo–Ni) were prepared and tested in plasma-catalytic NH₃ decomposition, where 6Fe–4Ni catalyst exhibited the highest activity and synergistic capability with plasma. At 500°C, NH₃ were completely decomposed (>99.9% NH₃ conversion); the rate of H₂ production and the energy consumption of H₂ production reached 0.96 mol g⁻¹ h⁻¹ and 0.050 kW h (mol g⁻¹)⁻¹, respectively. The 200 h continuous operation results indicate an excellent durability of 6Fe–4Ni catalyst. The catalysts characterization and plasma diagnosis results indicate that NH₃ was pre-activated by plasma into excited-state species (NH₃, ˙NH₂, and ˙NH), and the 6Fe–4Ni catalyst exhibited the highest capability to adsorb excited NH₃, ˙NH₂, and ˙NH species, which could be the main reason why 6Fe–4Ni catalyst exhibited the highest activity. © 2018 American Institute of Chemical Engineers AIChE J, 65: 691–701, 2019     

Novel catalyst-support interaction for direct formic acid fuel cell anodes: Pd electrodeposition on surface-modified graphite felt

The electrodeposition of Pd on graphite felt (GF, thickness ~3 mm in uncompressed state) was studied and the resulting catalyst was compared with Pt-Ru/GF for the electro-oxidation of formic acid. A micellar solution composed of the non-ionic surfactant Triton X-102 and an aqueous phase containing PdCl₂ were utilized for the galvanostatic electrodeposition of Pd nanoparticles. The presence of the surfactant during electrodeposition coupled with pretreatment of the GF surface by a Shipley-type method (PdCl₂ + SnCl₂ solution) creating nucleation sites had a major impact on the Pd catalyst morphology and penetration throughout the electrode thickness, affecting, therefore, the electrocatalytic activity toward formic acid oxidation. It was found that large (~1,000 nm) Pd particles with smooth surface favored the indirect CO_ad pathway, while Pd nanoparticles (diameter <40 nm) with rough surface, formed with surfactant and pretreatment, were much more active leading to the direct non-CO_ad pathway. Due to pretreatment the GF surface has been modified and the effective catalytic system could be described as Pd/SnO₂–Pd(PdO)/GF with possible electronic interaction between support and catalyst. In direct formic acid fuel cell (DFAFC) experiments at 333 K and 1 M HCOOH, the peak power density using the Pd/GF anode reached 852 W m^?2 (57 g m^?2 Pd) compared to 392 W m^?2 (40 g m^?2 Pd) with a commercial Pd catalyst-coated membrane (CCM). The long-term stability of Pd-based anodes was poor and inferior to Pt–Ru (4:1 at. ratio) prepared and tested under identical conditions.     

Screening of PdM and PtM catalysts in a multi-anode direct formic acid fuel cell

Direct formic acid fuel cells (DFAFC) currently employ either Pt-based or Pd-based anode catalysts for oxidation of formic acid. However, improvements are needed in either the activity of Pt-based catalysts or the stability of Pd-based catalysts. In this study, a number of carbon-supported Pt-based and Pd-based catalysts, were prepared by co-depositing PdM (M = Bi, Mo, or V) on Vulcan^® XC-72 carbon black, or depositing another metal (Pb or Sn) on a Pt/C catalyst. These catalysts were systematically evaluated and compared with commercial Pd/C, PtRu/C, and Pt/C catalysts in a multi-anode DFAFC. The PtPb/C and PtSn/C catalysts were found to show significantly higher activities than the commercial Pt/C catalyst, while the PdBi/C provided higher stability than the commercial Pd/C catalyst.     

Hydrocracking of Vacuum Gasoil on NiMoW/AAS-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> Trimetallic Catalysts: Effect of the W : Mo Ratio

The effect of the W: (W + Mo) atomic ratio in NiMoW trimetallic catalysts on their catalytic and physicochemical properties is studied. The catalysts are prepared by impregnating a carrier containing amorphous aluminosilicate (AAS) and aluminium oxide with an aqueous solution containing Ni, Mo, W compounds, and citric acid. They are studied via XRF, TEM, NH₃ TPD, and low-temperature nitrogen adsorption and are tested in the hydrocracking of vacuum gasoil (VGO). The average length of a sulfide active component layer shrinks as the amount of Mo increases and the amount of W in the catalyst is reduced. XPS data indicate that the degree of sulfidation of tungsten in NiMoW trimetallic catalysts is lower than in NiW catalyst. Testing of the catalysts in hydrocracking of a straight-line VGO at 390–420°C, 16 MPa, a feedstock hourly space velocity (FHSV) of 0.71 h^?1, and a H₂: VGO ratio of 1200 L/L shows the activities of hydrodesulfurization, hydrodenitrogenation, hydrogenation, and hydrocracking grow along with the W: (W + Mo) ratio. When the process pressure is high and the amount of sulfur in the NiW feedstock is low, the catalysts have higher activity in the target reactions of VGO hydrocracking than NiMo catalyst.     

Evaluation of the Performance of Carbon Supported Pt–Ru–Ni–P as Anode Catalyst for Methanol Electrooxidation

This research is aimed to improve the activity and stability of ternary alloy Pt–Ru–Ni/C catalyst. A novel anodic catalyst for direct methanol fuel cell (DMFC), carbon supported Pt–Ru–Ni–P nanoparticles, has been prepared by chemical reduction method by using NaH₂PO₂ as a reducing agent. One glassy carbon disc working electrode is used to test the catalytic performances of the homemade catalysts by cyclic voltammetric (CV), chronoamperometric (CA) and amperometric i–t measurements in a solution of 0.5 mol L^–1 H₂SO₄ and 0.5 mol L^–1 CH₃OH. The compositions, particle sizes and morphology of home‐made catalysts are evaluated by means of energy dispersive analysis of X‐ray (EDAX), X‐ray diffraction (XRD) and transmission electron micrographs (TEM), respectively. TEM images show that Pt–Ru–Ni–P nanoparticles have an even size distribution with an average diameter of less than 2 nm. The results of CV, CA and i–t curves indicate that the Pt–Ru–Ni–P/C catalyst shows significantly higher activity and stability for methanol electrooxidation due to the presence of non‐metal phosphorus in comparison to Pt–Ru–Ni/C one. All experimental results indicate that the addition of non‐metallic phosphorus into the Pt–Ru–Ni/C catalyst has definite value of research and practical application for enhancing the performance of DMFC.     

Hydrogen production on Ni–Pd–Ce/γ-Al2O3 catalyst by partial oxidation and steam reforming of hydrocarbons for potential application in fuel cells

A series of catalysts of nickel–palladium–cerium supported upon alumina have been investigated in order to obtain a suitable catalyst that could be used in the process of producing hydrogen for the potential application in fuel cell by partial oxidation and steam reforming (POSR) of mixtures of hydrocarbons. Investigated results showed that little addition of cerium into Ni–Pd catalyst could definitely improve its stability of hydrogen production from mixtures of hydrocarbons by POSR method. The experimental results also showed that the optimum compositions of Ni–Pd–Ce catalyst were the molar ratio of Ni to Pd as 1:0.09 and containing of Ce 0.5 wt%, shortened as Ni–Pd–Ce-0.5 catalyst. XRD results for the typical catalysts showed that it mainly displayed the γ-Al₂O₃ and Ni peaks. SEM and TG results for the fresh and used Ni–Pd–Ce-0.5 catalysts, lasted for 540 h, did not show much difference on their surface patterns and TG curves, respectively. This indicated this catalyst would be a practical catalyst to produce hydrogen from liquid fuel by POSR method for potential application in fuel cells.     

Palladium-Based Catalysts with Improved Sulphur Tolerance for Diesel-Engine Exhaust Systems

Palladium-based catalysts have been developed for the diesel exhaust system with an emphasis on their sulphur tolerance during the simultaneous oxidation of CO and HC. Promising materials include Au–Pd–Pt, Co–Pd–Pt and Ni–Pd–Pt supported on Al₂O₃ or TiO₂ and Pd–Pt/MoO₃–Al₂O₃ with the Al₂O₃ support modified with MoO₃ monolayer.     

Effects of iron-tetrasulfophthalocyanine on the catalytic activities of Pt/C,PtRu/C,and Pd/C catalysts in a multi-anode direct formic acid fuel cell

This paper reports a systematic study of the effects of a promoter, iron-tetrasulfophthalocyanine (FeTSPc), on the catalytic activities of carbon supported Pt, PtRu, and Pd catalysts (Pt/C, PtRu/C, and Pd/C) for formic acid oxidation. A multi-anode direct formic acid fuel cell (DFAFC) was used to compare the effects on each catalyst of adding FeTSPc to the fuel stream. The FeTSPc significantly enhanced the activity of the Pt/C catalyst, but had little effect on the PtRu/C catalyst. The activity of the Pd/C catalyst was inhibited by the FeTSPc. A FeTSPc modified Pt/C was also evaluated in a conventional 5 cm² DFAFC.     

Hydrogen Production with a Microchannel Reactor by Tri-Reforming; Reaction System Comparison and Catalyst Development

In this work, Pt based mono and bimetallic catalysts were tested under conditions of tri-reforming (TR). All the catalysts contained 25% of CeO₂ and a metal loading of 2.5 or 5.0% (wt%). The bimetallic catalysts contained 2.5% Pt and 2.5% of Me, where Me?=?Ni, Co, Mo, Pd, Fe, Re, Y, Cu or Zn. For all the experiments, a synthetic biogas which consisted of 60% CH₄ and 40% CO₂ (vol.) was mixed with water, S/C?=?1.0, and oxygen, O₂/CH₄?=?0.25, and fed to a fixed bed reactor (FBR) system or a microreactor. The 2.5Pt catalyst was used in order to compare the performance of each reaction system. The tests were performed at reaction temperatures between 700 and 800?°C, and at volume hourly space velocities (VHSV) between 100 L_N/(h g_cat) and 200 L_N/(h g_cat) for the FBR system and between 1000 L_N/(h g_cat) and 2000 L_N/(h g_cat) for the microreactor, at atmospheric pressure. Then, all catalysts were deposited into microchannel reactors and tested at a constant VHSV of 2000 L_N/(h g_cat) and reaction temperatures between 700 and 800?°C. Catalysts under investigation were characterized applying the following techniques: inductively coupled plasma optical emission spectroscopy (ICP-OES), N₂ Physisorption, Temperature Programmed Reduction (TPR), CO chemisorption, Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The microreactor was identified as the most efficient and promising reaction system, and the 2.5(Pt–Pd) catalyst as the bimetallic formulation with the highest activity. Therefore its activity and stability was compared with the reference 5.0Pt catalyst at 700?°C and VHSV of 2000 L_N/(h g_cat) for more than 100 h. Although slightly lower activity was measured operating with the 2.5(Pt–Pd) catalyst, a significant reduction of the Pt content compared to the reference 5.0Pt catalyst was achieved through the incorporation of Pd.     

Increased generation of electricity in a microbial fuel cell using <Emphasis Type="Italic">Geobacter sulfurreducens</Emphasis>

The microbial fuel cell (MFC) has attracted research attention as a biotechnology capable of converting hydrocarbon into electricity production by using metal reducing bacteria as a biocatalyst. Electricity generation using a microbial fuel cell (MFC) was investigated with acetate as the fuel and Geobacter sulfurreducens as the biocatalyst on the anode electrode. Stable current production of 0.20–0.24 mA was obtained at 30–32 °C. The maximum power density of 418–470 mW/m², obtained at an external resistor of 1,000 Ω, was increased over 2-fold (from 418 to 866 mW/m²) as the Pt loading on the cathode electrode was increased from 0.5 to 3.0 mg Pt/cm². The optimal batch mode temperature was between 30 and 32 °C with a maximum power density of 418–470 mW/m². The optimal temperature and Pt loading for MFC were determined in this study. Our results demonstrate that the cathode reaction related through the Pt loading on the cathode electrode is a bottleneck for the MFC’s performance.     

Computer Modeling System of the Industrial Diesel Fuel Catalytic Dewaxing Process

An unsteady mathematical model and a computer modeling system of the diesel fuel catalytic dewaxing process (mild hydrocracking) were developed. The modeling system allows for calculating the optimal technological mode to produce low‐freezing diesel fuel with the required cold filter plugging point taking into account the feedstock composition and catalyst activity. The modeling system consists of the main blocks: database, knowledge base, unsteady mathematical model of the diesel fuel catalytic dewaxing process, and application program package. Using the developed computer modeling system, the influence of the feedstock composition and flow rate as well as of the catalyst activity on the cold filter plugging point and the yield of diesel fuel is demonstrated.     

Particle Size Effect on CH4 Oxidation Over Noble Metals: Comparison of Pt and Pd Catalysts

Intrinsic catalytic activities (TOF values) in CH₄ complete oxidation under lean conditions were estimated as a function of Pt and Pd particle sizes (d_m) for two series of Pt/Al₂O₃ and Pd/Al₂O₃ catalysts. Comparison of TOF ~ f(d_m) relationships revealed significant difference between Pt and Pd catalysts. For Pt catalyst TOF showed tendency to increase by 2–3 times with increasing particle size from 1 to ca 3 nm and remained constant, when Pt particles became larger than 3 nm. On the other hand, for Pd catalyst TOF increased almost linearly when particle size grew from 1 to 20 nm. These different tendencies were attributed to the different mechanisms of CH₄ oxidation over Pt and Pd catalysts: Langmuir–Hinshelwood and Mars-Van Krevelen respectively.     

Effect of Nickel Addition on Ceria‐Supported Platinum Catalysts for Medium‐Temperature Shift Reaction in Fuel Processors

Medium‐temperature shift reaction (MTS, 280–340 °C) has received much attention for use in fuel processors. In this study, bifunctional Pt‐Ni/CeO₂ catalysts were prepared by different Pt (0.1–0.5 %) and Ni (5–20 %) loadings, and investigated for MTS reaction. X‐ray diffraction, N₂ adsorption and temperature‐programmed reduction tests were used to characterize the prepared samples. The results showed that Pt‐Ni bimetallic catalysts have higher CO conversion in comparison to Pt/CeO₂ monometallic catalyst. Furthermore, the sequential synthesis method of Pt and Ni impregnation was preferred to the simultaneous one, which is due to the better Pt dispersion on catalytic surface. Steam to carbon ratio variations study showed the maximum CO conversion to be in the range of 4.5.     

Conversion of methane on catalysts obtained via self-propagating high-temperature synthesis

Monolith metalloceramic catalysts for the selective oxidation of methane are prepared via self-propagating high-temperature synthesis (SHS) from NiO, ZrO₂, MgO, Al, Ni and other powders. Catalytic tests of monolith samples are performed in a flow reactor at 800°C using a methane-air mixture (methane, 29.6 vol %). SHS catalysts are shown to attain the level of platinum and platinum/rhodium catalysts through the yield of syngas (CO + H₂) and to surpass them in the case of Ni 52.9 ZrO₂ 9.5 composition. The latter is used as a catalyst to develop a pilot autothermal syngas generator with a capacity of 30 m³/h. Syngas is generated via carbon dioxide methane conversion (CDMC) on SHS platinum-modified Ni₃Al powder catalysts. The samples are tested in a flow fixed-bed reactor at a catalyst volume of 1 cm³, a grain size of 600–1000 μm, temperatures of 600–900°C, and a volumetric flow rate of 100 cm³/min (CH₄ : CO₂ : He = 20 : 20 : 60 vol %). The catalysts developed for converting natural gas into syngas are shown to be highly active and stable in a high-temperature redox medium. This work is the first step in the synthesis of dimethyl ether, which could compete successfully with diesel fuel.     

NiCoFe/C cathode electrocatalysts for direct ethanol fuel cells

A direct ethanol fuel cell (DEFC), which is less prone to ethanol crossover, is reported. The cell consists of PtRu/C catalyst as the anode, Nafion^® 117 membrane, and Ni–Co–Fe (NCF) composite catalyst as the cathode. The NCF catalyst was synthesized by mixing Ni, Co, and Fe complexes into a polymer matrix (melamine-formaldehyde resins), followed by heating the mixture at 800 °C under inert atmosphere. TEM and EDX experiments suggest that the NCF catalyst has alloy structures of Ni, Co and Fe. The catalytic activity of the NCF catalyst for the oxygen reduction reaction (ORR) was compared with that of commercially available Pt/C (CAP) catalyst at different ethanol concentrations. The decrease in open circuit voltage (V_oc) of the DEFC equipped with the NCF catalysts was less than that of CAP catalyst at higher ethanol concentrations. The NCF catalyst was less prone to ethanol oxidation at cathode even when ethanol crossover occurred through the Nafion^®117 film, which prevents voltage drop at the cathode. However, the CAP catalyst did oxidize ethanol at the cathode and caused a decrease in voltage at higher ethanol concentrations.