Applied Mechanics and Materials Vols. 448-453

Abstract: With the expansion of application fields of the high purity hydrogen (hydrogen content>99.9999%), its preparation methods, in particular recovery from multi-component mixture,have attracted wide attentions. This paper describes the principle of hydrogen separation and purification process based on metal hydride, and some key issues involved in it, such as the alternatives of raw gas, the processing of hydride materials, the design of metal hydride reactor are discussed according to the literature reports. Finally, the current problems encountered in hydride based gas separation are presented, and future trends are also predicted.

Abstract: The mechanism of CH₄-CO₂ free radical reforming was investigated by DFT and B3LYP methods. The gained results have indicated that the main dehydrogenation of CHx were lost hydroxide atom step by step.The form process of carboxyl was very easy. The decomposition of the carboxyl or the compound included carboxyl were direct decomposition into carbon monoxide at low temperature. The intermediate as ·COOH and CH₃COO·were also easy to take place the decomposited into carbon monoxide or CH₃O.The hydroxide radical also could combine CH₃·,CH₂·,CH· into sterols. The decomposition of CH_xO(x≠3) is easy and through direct dehydrogenation. The decomposition of methanol were three channels and it can creat H₂, C₂H₆, H₂O.

Abstract: PVP/[Y(NO₃)₃+Al (NO₃)₃] composite nanobelts were fabricated via electrospinning combined with sol-gel process and novel structure of Y₃Al₅O₁₂ (denoted as YAG for short) nanobelts have been obtained after calcination of the relevant composite nanobelts. The structural properties were characterized by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). XRD analysis indicated that the composite nanobelts were amorphous, and YAG nanobelts were cubic in structure with space group I_a3d. FTIR analysis manifested that pure YAG nanobelts were formed at 900oC. SEM analysis and histograms revealed that the width of the composite nanobelts and YAG nanobelts were 3.5 μm and 2.4 μm, and the thickness were 240 nm and 112 nm, respectively, under the 95% confidence level. The formation mechanism of YAG nanobelts was discussed in detail.

Abstract: As a mature tertiary oil recovery technology, polymer flooding has been widely used in domestic oilfields, especially in Daqing oilfield, its polymer flooding production has reached more than 25% of total output. Therefore, there are important theoretical significance and application value to do further research of polymer flooding mechanism and use to guide the production. In order to understand the mechanism of polymer flooding, polymer flooding oil film based on the decrease of residual oil range is the biggest, established the dynamics model of polymer solution displacement of rock wall oil film under the condition of tensile and shear flow. In addition, this paper discussed the effect of the oil film thickness, tensile index, dimensionless tensile coefficient as well as the power-law coefficient on oil film start, and pointed out macroeconomic conditions which is the oil film start required.

Abstract: This paper studies the chemical composition of biodiesel, cold flow properties, and the influence of chemical composition on cold filter plugging point (CFPP) by using GC-MS and CFPP tester according to the theories of crystallization. Using the method of multivariate linear regression to analyze the correlation between chemical composition and CFPP, the prediction model of CFPP which has a very significant linear correlation and is based on chemical composition is built. The study shows that biodiesel is mainly fatty acid methyl ester (FAME) that is composed of 14-24 even number carbon atoms (C_14:0~C_24:0 , C_16:1~C_22:1, C_18:2~C_20:2 and C_18:3). The CFPP increases linearly with the increase of the content of SFAME and the longer the carbon chains are, the greater the increase will be; the CFPP decreases linearly with the increase of the content of UFAME. Among the 120 kinds of biodiesel we studied, the CFPP of Chinese tallow methyl ester (CTME) is the lowest (-14 °C) and the CFPP of peanut methyl ester (PNME) is the highest (13 °C).

Abstract: Dimethyldichlorosilane hydrolysis devices are now faced with problems of incomplete reaction and emulsion between the mixture of siloxane and the hydrochloric acid. This paper adopted ideas of falling film and designed a inclined plate to avoid the problems. CFD software was used to simulate the water-oil falling film on the plate.The simulation results show that using a inclined plate within the reactor can expand the contact area between water and oil effectively. The hydrolysis reaction is completed and there is no emulsified phenomenon happening by using the plate.

Abstract: The technology was used for handling aging oil by demulsifier thermal chemical deposition and horizontal scrow centrifuge. Under certain temperature, The heavy aging oil, mixed with a certain Demulsifier for demulsification, is loaded into the packaging three-phase Horizontal Screw Centrifuge for oil, water and soil separation, the water content of processed oil dropped to 10% below which meet oil remix and fuel oil requirement. The influence of liquid level adjusting board, the handling capacity, processing temperature and operating parameters of centrifuges are all discussed as well.

Abstract: With the high temperature gas chromatography, wax compositions and different n-alkanes content of typical well 7-1 in Hainan block of Liaohe Oil Field is analysed completely, obtained average carbon numbers of oil wax. And under its cloud point temperature separately,original oil and additive crude oil are separated by the centrifuge. From the centrifugate and the gel wax components analysis, the LHPPH-2 pour point depressant used in Hainan block and wax components of 7-1 well have a good adaptability, show an excellent effect.

Abstract: A compact autothermal reformer suitable for liquid fuel for instance methanol et al. was developed. The fuel reformer was combined with polymer electrolyte membrane fuel cells (PEM FC) and a system test of the process chain was successfully performed. The fuel processor consists of a fuel evaporating step, two-stage reformer and a two-stage reactor of water gas shift (WGS, one for high temperature water gas shift and the other for low temperature water gas shifter) and a four-stage preferential oxidation (PROX) reactor and some internal heat exchanger in order to achieve optimized heat integration. The fuel processor is designed to provide enough hydrogen for 75kWel fuel cells. After the initial step of methanol ATR, CO WGS and CO PROX steps are used for 'clean-up' CO. The exhaust gas from FC anode feedback to the fuel processor to vaporizes the feedstock of methanol and water by a catalytic combusting-evaporator. The hydrogen source system can produce hydrogen 70.5 m3/hr and its specific gravity power and specific volume power reach 255W/kg and 450W/L respectively. During three hours coupling experiment, the fuel processing system and the fuel cells all has been running smoothly. The volume concentration of H2 and CO in product gas (dry basis) was kept in 53% and 20ppm respectively, completely meeting the requirements of PEM fuel cells. The conversion efficiency of the hydrogen producing system based on LHV of fuel and hydrogen can exceed 95.85%. The fuel cells stacks put up strong resistance to CO and its maximum electronic load to the fuel cells reaches 75.5kW. It indicates that it is feasible technically for supplying hydrogen for Proton Exchange Membrane Fuel Cells by catalytic reforming of hydrogen-rich liquid fuel on-board or on-site.

Abstract: Using numerical simulation method, under the adiabatic condition, this paper simulates the of the upstream gas liquid two phase flow in main tube of hydraulic diameter 1 mm T tube. Superficial gas velocity within 0.01~30m/s and fluid velocity within 0.01~5m/s, under simulated by two kinds of gas volume fraction, air-water flow diagram and the flow pattern transition boundary have been got from the simulation. By comparing the simulation results, it shows that under the same environment, small channel volume fraction of gas has important influence on convection type transition boundaries.