Advanced Materials Research Vols. 236-238

Abstract: The deactivation behavior of industrial hydrodemetallization catalysts was investigated in the presented work. The main objective of the study is to contribute to a better understanding of the nature of the coke and metal deposition on the used catalysts by applying chemical analysis and various advanced analytical techniques, such as X-ray diffraction analysis (XRD), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), and solid-state carbon-13 nuclear magnetic resonance spectroscopy (¹³C NMR). The results are discussed scientifically based on the physico–chemical properties of origin and used catalysts.

Abstract: The object of this paper is to study the effects of nanofluid on NH₃/H₂O bubble absorption performance under adiabatic and non-adiabatic conditions. Mono nano Ag with the concentration of 0.02wt% was used as the enhancement medium, and the absorption performance experiments under the heat insulation and water cooling for absorption test section were respectively conducted and contrastively analyzed. The results showed that the absorption rate with mono nano Ag in bubble absorption process is higher than that without any nanoparticles; in adiabatic case, when the initial temperature of NH₃/H₂O solution is gradually increased within 6～18°C, the absorption rate decreases correspondingly, and so does the effective absorption ratio; in non-adiabatic case, with the cooling water temperature rising within 10～25°C, the absorption rate decreases but the effective absorption ratio increases. Therefore, it is concluded that the heat transfer enhancement of nanofluid can promote the NH₃/H₂O bubble absorption performance to a certain degree, and the enhancement of the absorption is not completely dependent on heat transfer.

Abstract: High performance trend of plastics has become a hot spot of current research. Select bisphenol A dianhydride and bisphenol A diamine with excellent water resistance as the reactant monomers to obtain anhydride-terminated polyimide with very high molecular weight by two-step polymerization, graft the active radicals of acyl caprolactam using the activity of anhydride and obtain PI modified nylon resin by polymerization. It is proved that the reaction in each above step is successful through infrared analysis. Through microscopic analysis, the molecules of polyimide does not enter crystallization phase of nylon resin, but forms compact lamellar crystals existing in nylon matrix.

Abstract: In this paper, a new type lithium hexafluorophosphate (LiPF₆) complex was prepared with a new method using phosphorus pentachlorine (PCl₅), lithium fluoride (LiF) and 1,2-dimethoxyethane (C₄H₁₀O₂). The structure of the complex was carefully characterized by FTIR, TG-DTG, ¹H NMR and ³¹P NMR. FTIR results indicate that the synthesized complex is consisted of LiPF₆ and C₄H₁₀O₂. Chemical analysis shows that the content of LiPF₆ in the complex is about 45%, which could infer that the mole ratio of LiPF₆ and LiPF₆(C₄H₁₀O₂)₂ in the complex is 1:2. The results of ¹H NMR and ³¹P NMR further confirm the composition of the complex and determine the structure. The molecular formula of the LiPF₆ complex is LiPF₆(C₄H₁₀O₂)₂. Thermal analysis shows that the strong decomposition peaks of the complex appear at 75°C and 175°C. LiPF₆(C₄H₁₀O₂)₂ may be used in the electrolyte of the lithium ion battery which 1,2-dimethoxyethane is permitted or broke down into LiPF₆ after further preparation.

Abstract: In order to study the influence of gas supply modes on CO₂ hydrate formation characteristics, a specific water spray gas hydrate formation apparatus was designed. The gas consumption and temperature variation in the process of CO₂ hydrate formation under continuous and oscillating gas supply modes were researched. The experimental results showed that hydrate formation rate in the oscillating gas supply mode was greater than in the continuous gas supply mode, which indicates mass transfer driving force caused by disturbance in oscillating gas supply mode is larger than that of continuous gas supply mode. Additionally, under the same initial pressures and the same gas supplying mode, the lower the initial temperature, the larger the heat transfer drive force, and the faster the hydrate formation rate.

Abstract: An Indonesia natural asphalt was ultrasonically extracted with acetone and carbon disulfide to afford acetone-soluble fraction (F₁), carbon disulfide-soluble fraction (F₂) and residue (i.e., carbon disulfide-insoluble fraction, R₂). F1 was analyzed with GC/MS and all the fractions were analyzed with FTIR. The results show that F1 is rich in hetero atomic compounds (HACs), 2-methyl alkanes (2-MAs) and phthalic acid esters (PAEs). The 2-MAs are a class of important biomarkers, in which the main peak carbons are C24 and C18. According to the proximate analyse, there is a sharply high content of ash (42.62%), which could be responsible for the increase in the yields of R2 in the natural asphalt. By FTIR analysis, the nitrogen- and oxygen-containing compounds, branched alkanes and esters (or lactones, etc.) are important components for the Indonesia natural asphalt.

Abstract: Four natural asphalts (NAs) from Buton Rock, Indonesia, which were abbreviated as BRA-A, BRA-B, BRA-C and BAR-D, were continuously extracted by solvents, subdivided into four fractions and analyzed with Fourier transform infrared (FTIR) spectrometry. The transmission and reflection FTIR techniques were used to distinguish among different samples and fractions and to examine information concerning their structure, composition and structural changes upon fractional extract. Upon FTIR analysis, the methyl, methylene, oxhydryl and carboxyl groups are the major composition of these NAs. Some strong bonds at the zones of 2922-2856 cm-1, 1707-1606 cm-1 , 1453-1373 cm-1 , 1030 cm-1 and 872-748 cm-1 are assigned to >CH2 & -CH3 & –OH in carboxlic acid, ester & benzene ring, >C=O & -C-CH3, –CH2OH, -(CH2)n- & substituted benzene, etc. Much more care should be taken to investigate both N-containing functional groups and mineral multiphase compositions probably present in BRA-B, C and D.

Abstract: A distributed parameter method has been established for a ground-source heat pump in this paper, with this model, the working process of this heat pump system was simulated. The results agree well with experimental data and show that heat-capacity and COP increase when the cooling water flow rate in the tube-in-tube heat exchanger increases; heat-capacity decreases when the temperature of inlet water of the tube-in-tube heat exchanger rises; COP, between 3.8 and 4.5, is higher than that of conventional air-source heat pumps.

Abstract: The characteristic groups of polymer were analyzed by the IR spectrometrer. The crystallinity of different style wax crystal and the fluid improver additive(FIA) were measured by the X-ray diffraction analysis. The results showed crystallinity of wax crystal was close correlation with the polymer fluid improver and the change of wax crystal dispersibilty will be caused by the difference of crystallinity which make change of pour point depressing behaviour of the crude oil. At the same time found when crystallinity of the wax crystal was match with the additive the wax crystal dispersibilty and pour point depressing and viscosity depressing will change well that was proved by fluid behaviour improving at low temperature of crude oil system.

Abstract: Five types of active carbon’s adsorption isotherm of nitrogen at 77K were measured, and their adsorption characteristic were analysed. The results show AC1, AC2 and AC3 have a lot of micropores for they have high nitrogen adsorbance in low pressure at 77K. The HK model was employed to analysis the pore size distribution of the adsorbance. AC1 has most developed microspore structure, its surface area reached 1706㎡/g, and its pore size mainly concentrated at 4.6 angstroms. Then the five adsorbents’ adsorption isotherm on methane, oxygen and nitrogen at 298K, 308K and 318K were measured. Methane’s adsorption capacity on active carbon is much higher than nitrogen and oxygen, and the adsorbance of nitrogen and oxygen have little difference, so the coal mine methane could be regarded as the binary of methane and nitrogen on methane separation by adsorption method. AC1 has the highest methane adsorbance and equilibrium selectivity factor of methane to nitrogen. Then the adsorption heat was studied, the results show that the isosteric heat of methane on AC1 decreased from 20.6kJ/mol to 19.55kJ/mol when the adsorbance of methane increases from 0.4 mol/kg to 1.2mol/kg, and methane’s adsorption heat is higher than nitrogen.