Advanced Materials Research Vols. 750-752

Abstract: Based on the preparation of zinc acetate/activated carbon catalyst in the fluidized bed reactor, the Eulerian multiphase model in Fluent was used to numerically simulate the gas-liquid-solid flow and the gas-solid-solid flow hydrodynamic characteristics in fluidized beds. The instantaneous phase volume fraction and the flow hydrodynamic characteristics of the three phases were analyzed, and in view of the zinc acetate/activated carbon catalyst with bad uniformity prepared by present method, a new mode of operation with dynamic rules was proposed. The simulation results show that activated carbon particles with different density can realize layer inversion using this mode of operation, and the uniformity of zinc acetate/activated carbon catalyst will be effectively improved.

Abstract: Two new Ce(III) coordination polymers formulated as Ce(bpdc)(Hbpdc)(DMF)2 (1) and [Ce2(bpdc)3(DMF)2(H2O)4]·2DMF (2) (H2bpdc = 2,2'-bipyridine-4,4'-dicarboxylic acid, DMF = N,N-Dimethyl formamide) have been synthesized under solvothermal condition and characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in monoclinic, space group C2/c with a = 2.2520(2), b = 1.17787(12), c = 1.16128(11) nm, α = 90, β = 95.5600(10), γ = 90°, V = 3.0658(5) nm3, Z = 4, Mr = 771.70, Dc = 1.672×10-9 g/cm3. Compound 2 crystallizes in triclinic, space group Pwith a = 1.00610(10), b = 1.17219(11), c = 1.36891(14) nm, α = 66.9340(10), β = 87.182(2), γ = 76.2570(10) °, V = 1.4411(2) nm3, Z = 1, Mr = 1371.25, Dc = 1.580×10-9 g/cm3. Both compounds exhibit 3D Ce(III)–organic frameworks. Furthermore, thermal stability and luminescent properties were also investigated. CCDC:(1)913670, (2)909563.

Abstract: Coking characteristics of China RP-3 under high temperature (above 650°C) and long-duration (20 minutes) conditions, especially the effects of temperature, pressure, and inner diameter of cooling channels on coking amount were experimentally investigated. Temperature of kerosene in experiments varied from 650°C to 730°C, pressure varied from 1.8MPa to 3.5MPa, and the mass flow rate was approximately 120g/min. Results showed that temperature has a significant influence on coking amount. Even a small increment of temperature induces remarkable coke formation. However, pressure and inner diameter of the tube has a relatively little effect on it. The coking amount increases as pressure and inner diameter increase, but the increasing rate is decreasing. It is considered that inner diameter mainly affects residence time. When residence time increases to some extent, coking amount begins to grow slowly even stop increasing. This is resulted from two reasons. Firstly, the cracking conversion percentage reaches an upper limit when residence time is adequately long; secondly, coke gradually covers the inner wall of the tube, leading to isolation of kerosene from the metal surface to form coking.

Abstract: The paper presents a bespoke mathematical model that simulates the electrochemical, thermal and fluid-dynamic interactions in a solid oxide fuel cell. This model is created for the purpose of evaluating and optimising a novel SOFC architecture. The proprietary fuel cell design consists of cathode supported cross-flow monolithic flow channels of hexagonal honeycomb section. The monolithic cells are constructed from porous cathodic material, with porous anodic and dense electrolytic material deposited inside specific hexagons such that any anodic cell is surrounded by six cathodic cells. Current collection is achieved by bus-plating on the monolith perpendicular to the direction of flow, and using thin interconnects attached to a corner of an anodic cell. The mathematical model considers a single side of the hexagon to simulate electrochemical interactions combined with heat and mass transfer. The finite difference technique is applied to predict numerically from a given current value voltage potential, temperature, fuel and oxidant compositions and partial pressures at the electrolyte/electrode interfaces. The model can be treated as a small segment of any geometry, thus can be, with added complexities of non-uniformity in surface thickness, extended to other shapes, and therefore used as an aid at the design stage to choose the values of geometric variables such as electrode and electrolyte thickness, etc.

Abstract: Many combustion processes seriously pollute the environment because of producing nitrogen oxides emission, which abstracts wide attention from researchers. How to reduce nitrogen oxides emission is important to protect the environment. At the present work, a reduction mechanism based on a detailed chemical reaction kinetics mechanism, Gri_Mech3.0 was adopted to analyze nitrogen oxides formation in a CH₄/air laminar premixed and turbulent diffusion flames, a two dimensional turbulent diffusion flame was simulated with the EDC model. Parameters were obtained, including flame temperature, burning velocity and mass fraction of nitrogen oxides. The results of laminar premixed flame show that nitrogen oxides emission mainly comes from the thermal and prompt NO mechanisms. A large amount of free radicals O, H and OH produced by combustion processes provide reactants for the reactions of nitrogen oxides formation. Mole fraction of nitrogen oxides increases with the increasing of both flame temperature and chemical equivalence ratios. By contrast, there is a lower mass fraction of nitrogen oxides formation for the fuel-lean flame.

Abstract: MgAl-NO₃ LDHs were prepared by hydrothermal method. The as-prepared samples were characterized by SEM, XRD and FT-IR. The adsorption performance of MgAl-NO₃ LDHs to methyl orange (MO) was studied. The effects of Mg/Al molar ratio on the adsorption performance of MgAl-NO₃ LDHs were investigated. The results showed that the highest adsorption capacity of 499.98mg/g was obtained when the Mg/Al molar ratio was at 2.5:1.

Abstract: The effect of different promoters and the content of promoters on the hydrorefining catalyst for hydrocracking process were studied. The results showed that specific promoter can effectively change the properties of carriers, which resulted in the catalysts have large surface area, high activity,and suitable acidity. When the content of promoter was three percent, the catalyst had the best performance. The evaluation results revealed the reaction temperature of developped catalyst was lower 6°C than that of the reference catalyst on the condition of obtaining the same products.

Abstract: The Silicon-chrome-green Pigment is synthesized with solid reaction process, and is tested by XRD. Influence of mineralizer on color and mechanism of action are discussed. The variety and content of mineralizer which suit the Silicon-chrome-green Pigment are determined.

Abstract: Four new arylamine-acetylene bridged tetrahedral iron and cobalt carbonyl clusters, [Co₂(CO)₄(μ-CO)₂₍η², μ-TMSCCPh)₂N 1, [Fe₂(CO)₆(μ-CO)(η², μ-TMSCCPh)NH(PhCC TMS)] 2, [(Co₂(CO)₆(η², μ-TMSCCPh))₃ 3 and [(Fe₂(CO)₆(μ-CO)(η², μ-TMSCCPh))₂N(Ph CCTMS)] 4, were obtained by reactions of Co₂(CO)₈ and Fe₃(CO)₁₂ with the bis [4-((trimethylsilyl) ethynyl) phenyamine and tris [4-((trimethylsilyl) ethynyl) phenyamine compounds in suitable solvent, respectively. All clusters are confirmed by C/H elemental analysis, MS, ¹HNMR and FT-IR spectroscopy. Furthermore, the electrochemical and optical properties of some clusters were also determined by cyclic voltammogram (CV) analysis and UV-Vis spectra.

Abstract: The super-fine aluminum hydroxide was prepared by crystal seed precipitation from sodium aluminate solutions in this study. The influence of NaOH concentration, [NaO/[Al (OH)₃] molar ratio, precipitation temperature, and precipitation time on the particle size of super-fine aluminum hydroxide was investigated. The results show that the optimum conditions were: NaOH concentration be 180 g/L, [NaO/[Al (OH)₃] molar ratio be 1.15, precipitation temperature be 40°C, and precipitation time be 26 h.