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Xu W.-W.,National Engineering Research Center for Distillation Technology | Xu W.-W.,Tianjin University | Li Y.-H.,National Engineering Research Center for Distillation Technology | Li Y.-H.,Tianjin University | Li Y.-H.,Key Laboratory for Green Chemical Technology of State Education Ministry
Xiandai Huagong/Modern Chemical Industry | Year: 2014

A new method for updating the quality of heavy oil in supercritical/near-critical water is mainly focused on in this article. The changes of properties including the C/H ratio, viscosity, saturated hydrocarbons content, aromatic hydrocarbon, and so forth, are described. Meanwhile, upgrading of heavy oil in supercritical/near-critical water is a green and economical technology when it is compared with traditional way, for example upgrading the oil's quality by water-thermal cracking or using the supercritical inert gas. In addition, the effects of carbon dioxide, hydrogen, and acid-base components on upgrading heavy oil in supercritical water are investigated. The merits and drawbacks of different ways for upgrading heavy oil are compared through the analysis of products. The differences are discussed by analyzing the role of various substances on the progress of upgrading heavy oil. At last, the hydrogen donors are summarized comprehensively, and their effects on upgrading heavy oil in supercritical water are also investigated. Source


Shi R.-H.,Tianjin University | Shi R.-H.,National Engineering Research Center for Distillation Technology | Li Y.-H.,Tianjin University | Li Y.-H.,Key Laboratory for Green Chemical Technology of State Education Ministry | And 3 more authors.
Xiandai Huagong/Modern Chemical Industry | Year: 2014

Nickel based catalyst 7.5% Ni/(κ+θ+α)-Al2O3 is studied by presulfidation treatment. The influences of sulfides, sulfidity, presulfidation temperature and concentration of sulfide on catalytic performance in selective hydrogenation of isoprene are studied, which aims to improve the mono-olefins selectivity with minimal loss of hydrogenation activity. The selectivity of mono-olefins can be greatly improved (from 0 to 93%) in the optimum conditions. By the discussion of poisoning mechanism with CS2, it is found that CS2 can easily deactivate the catalyst at low temperature. The metal sulfide formation and CS2 physical adsorption on the catalyst surface lead to catalyst deactivation. Source


Li X.,Tianjin University | Chen C.,Tianjin University | Chen Y.,Tianjin University | Chen Y.,Key Laboratory for Green Chemical Technology of State Education Ministry | And 3 more authors.
Energy and Fuels | Year: 2015

The methane hydrate formation kinetics in water-in-oil (w/o) emulsion was measured using the pressure-volume-temperature (PVT) method during isochoric, isothermal processes at an initial pressure of 6.80 MPa in an agitated reactor. The effects of agitation rates (n) of 300-1100 rpm, average water droplet diameters (dÌ...) at 30% water cut, and temperatures (T) of 269.15-277.15 K on the induction time and hydrate formation rate were systematically studied. The experimental results show that the induction time of hydrate formation initially decreased as the agitation rate increased and then increased when higher agitation rates were used. The results did not reveal any influence of the average diameter of the water droplets on induction time. Increasing the temperature increased the induction time. The rate of hydrate formation increased as the agitation rate increased and the average diameter and temperature decreased. The total methane hydrate formation was affected by the average diameter and temperature, and the hydrate formation rate was enhanced in w/o compared with many other methods. A mathematical model of hydrate formation kinetics in w/o was established based on crystal growth theory and the mass transfer of methane. The effects of the amounts of hydrate in a w/o system on the mass-transfer coefficient of the oil/water interface were considered by introducing an empirical equation. The parameters of the model were determined by correlating the experimental data with the model data. The agreement between the experimental data and the calculated results of the model was satisfactory. © 2015 American Chemical Society. Source


Chen Y.-N.,Tianjin University | Chen Y.-N.,Key Laboratory for Green Chemical Technology of State Education Ministry | Li Y.-H.,Tianjin University | Li Y.-H.,Key Laboratory for Green Chemical Technology of State Education Ministry | And 7 more authors.
Xiandai Huagong/Modern Chemical Industry | Year: 2014

A series of experiments are made to study the effect of impeller speed on hydrate formation. In experimental process, the temperature is set at 273.35 K. The initial pressure is about 6.80 MPa. The results show that the initial formation pressure of each experiment is almost the same, but the induction time of each experiment is different from others. As the impeller speed increases, both the absorption rate of methane and growth rate of hydrate increase apparently. But they increase little when the impeller speed reaches particular extent. Source


Wang X.,Key Laboratory for Green Chemical Technology of State Education Ministry | Li Y.,Key Laboratory for Green Chemical Technology of State Education Ministry | Li Y.,National Engineering Research Center for Distillation Technology
Fluid Phase Equilibria | Year: 2014

Isobaric vapor-liquid equilibrium (VLE) data of 2-ethylthiophene and n-octane binary system were measured at 101.33. kPa with a modified Rose-Williams still. Gas chromatography was used to analyze compositions of the samples from the vapor-liquid equilibrium system. The VLE measurement passed the thermodynamic consistency test proposed by Herington and no azeotropic behavior was found. The experimental data were correlated by Wilson, the non-random two-liquid (NRTL) and universal quasi-chemical activity coefficient (UNIQUAC) models, respectively. The corresponding parameters for the three models were obtained. Results showed that the Wilson model gave better predictions than NRTL and UNIQUAC models. © 2014 Elsevier B.V. Source

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