In order to explore the microscopic mechanism of wax deposition on the pipe wall of high temperature and high?pressure condensate gas wells, this paper uses molecular dynamics simulation technology by the Materials Studio to build condensate oil system with methane, pentane, nonane,n?dodecane, cyclobutane, cyclopentane, benzene and toluene,and the wax component model was built with n?octadecane, and simulate with wax content, asphaltene and scale as variables. The results show that with the increase of wax and asphaltene mass fraction, the wall wax deposition behavior can be intensified, but when the asphalt mass fraction reaches 2.0%,the wall wax deposition behavior can be inhibited.The more kinds of heteroatoms in asphaltene,the more obvious the promotion effect.When there is scale on the pipe wall, sulfate scale has a great influence on wax deposition.The understanding of microscopic mechanism provides a scientific basis for the treatment of wax deposition on the pipe wall.
Iridium (III) complexes have broad application prospects in luminescence detection of analyte due to advantages of large Stokes shift, high quantum yields, long luminescence lifetimes, flexible and adjustable emission spectra, and excellent optical and thermal stability. The novel iridium(III) complex Ir(ppyTPA)3 was prepared by introducing triphenylamine substituent on 2?phenylpyridine, and the structure, luminescence and electrochemical properties of Ir(ppyTPA)3 were characterized in detail. Then, the luminescence properties of Ir(ppyTPA)3 were used to detect five common nitroaromatics and the detection mechanism was studied. The results show that Ir(ppyTPA)3 has the highest detection efficiency to 3?nitrobenzoic acid with the detection efficiency constant KSV of 19.78 L/mmol. And the detection limit is as low as 2.89×10-3 mol/L. Spectral analysis and density functional theory calculations show that the detection mechanism of Ir(ppyTPA)3 for the five nitroarenes was the charge transfer mechanism.
Guaiacol (GUA) is extensively used as the model compound in catalytic studies of lignin, a most abundant renewable aromatic resource in nature. However, GUA is not easy to obtain good activity and selectivity in the hydrodeoxygenation reaction due to its complex structure with various reaction possibilities. So far, researchers have done great efforts to develop efficient catalysts and reaction processes for breakthroughs. This paper reviewed the research progress of transition metal catalysts and noble metal catalysts for hydrodeoxygenation of GUA, and discussed the reaction pathways and the factors which may affect the catalytic behavior, particularly focusing on their catalytic conversions of GUA to phenol or cyclohexanol through CAR-O bond cleavages and aromatic ring saturation. A prospect regarding the future research directions on the catalyst improvement and reaction process optimization were also presented.
The wet gas gathering pipelines will produce natural gas hydrate with the condition of high pressure and low temperature, which may cause blockage of pipelines or failure of key control equipment. Adding alcohols Thermodynamic?Inhibitor(THI) is one of the feasible proposals to prevent hydrate formation. If the amount of THI is poured excessive, the costs of procurement, transportation, storage and water treatment will increase in large quantities. Therefore, it is significant to determine the minimum dosage of THI based on a reasonable safety margin. Calculation of THI injection dosage based on empirical formula method and phase equilibrium software, without considering the effect of flow. In this paper, a method coupling of phase equilibrium and flow was used to optimize the injection dosage of THI. Based on the OLGA component tracking model, the temperature, pressure and THI concentration along the line are tracked, and then the THI dosage was predicted more accurately. Taking the gas gathering pipeline of land and submarine as an example, different calculation methods were compared. The results show that the new method can reduce the THI consumption by more than 10%.
The hydrogenation catalysts with Mo and Ni as active centers were modified with macroporous nano?alumina as carrier and iron as auxiliary agent, and Fe?Mo?Ni and Fe?Ni catalysts were prepared by secondary nano?self?assembly method respectively. The experimental results show that the iron modified catalysts MNF?70C and NF?70C have bimodal pore structure, the larger most probable pore diameter is 50.0 nm and 40.0 nm respectively, and the smaller most probable pore diameter is 5.5 nm. It can be seen that under the action of complexing agent and promoter Fe, Fe, Mo and Ni in MNF?70C catalyst form a large number of nano self?assemblies in the form of metal bonds on the inner and outer surfaces of macroporous alumina, which are more evenly dispersed and have more pores suitable for hydrogenation reaction. The pore size distribution of MNF?70C and NF?70C catalysts in the range of 6.0~60.0 nm reached 78.05% and 72.80% respectively. It shows that the addition of structural assistant iron improves the dispersion of active metals, so as to effectively improve the pore size distribution of the catalyst. The characterization analysis of CO adsorption, H2?TPR TEM and XPS further shows that the Fe modified catalyst has linear adsorption for CO, its reduction temperature is low, and it has been evenly dispersed in the form of nanoparticles, with more catalytic active centers, indicating that this kind of catalyst has better hydrogenation catalytic activity. Because Fe is cheap, the addition of additives can improve the quality of the oil after hydrogenation or reduce the amount of catalyst active metal, so as to reduce the cost of synthetic catalyst, which is suitable for the development of heavy oil hydrogenation catalyst for industrial application.