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Tianjin, China

Zhang X.,Tianjin University | Jian C.,Tianjin Univtech Co.
Journal of Chemical and Engineering Data | Year: 2012

The solubility and liquid-liquid equilibrium (LLE) data were measured for the ternary system methanol + acrylonitrile + water at 288.15 K, 298.15 K, and 313.15 K and atmospheric pressure. The quality of the experimental tie-line data has been checked by Hand and Othmer-Tobias correlations. The nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) models were applied to correlate the experimental data, and the interaction parameters for both models were regressed with an overall root-mean-square deviation (rmsd) less than 0.32 %. Selectivity values of water for methanol at the studied temperatures are within the range 1.5 < S < 26.5. The effect of temperature on the miscibility gap and the selectivity of water for methanol is minor. © 2011 American Chemical Society. Source

Wang Y.,Tianjin University | Du S.,Tianjin University | Zhu H.,Tianjin Univtech Co. | Ma H.,Tianjin University | Zuo S.,Tianjin University
Advanced Materials Research | Year: 2012

A 3D two-phase flow computational fluid dynamics (CFD) model containing gas mal-distribution is developed in the Eulerian framework to predict the hydraulics of a dividing wall sieve tray. Variable and position dependent gas superficial velocity is used in the calculation. Using water-air system, simulations of flow patterns and hydraulics of a commercial-scale 1.2m diameter sieve tray are carried out using this model to testify its precision. Then, the same simulations of a dividing wall sieve tray with equal diameter are carried out. The results show that there are two backflow regions on a dividing wall tray, one is in the segmental area, and the other is in the region nearby junction of dividing wall and outlet weir. In the segmental area of trays with equal diameter, the area of backflow region of dividing wall trays is basically equal to that of conventional trays. © (2012) Trans Tech Publications. Source

Wang Y.,Tianjin University | Zuo S.,Tianjin University | Zhu H.,Tianjin Univtech Co.
Advanced Materials Research | Year: 2013

Cyclic voltammograms were carried out to track the process of phenol electro-oxidation on GCE, understand the course and further guide the use in dealing with waste water. The effect of supporting electrolyte, phenol concentration, and scan rate were all tested. The results show that phenol oxidation contains several steps, and the first step is a mass transport process, while the following steps are not. What's more, alkaline solution facilitates the first step, but the produced polymer can foul GCE and hinder the oxidation reaction in turn. © (2013) Trans Tech Publications, Switzerland. Source

Zhang X.,Tianjin University | Zhang S.,Tianjin University | Jian C.,Tianjin Univtech Co.
Chemical Engineering Research and Design | Year: 2011

Methylal is an important raw material and an excellent solvent in industry. The conventional methods for the synthesis of methylal have drawbacks such as corrosion to the equipments, catalyst isolation, high molar ratio of methanol to formaldehyde and high cost of equipments. To overcome these drawbacks, the synthesis of methylal was investigated in a pilot scale catalytic distillation column using Sulzer BX and the structured catalytic packing Katapak-SP 12 in the present study. The reaction was catalyzed by polystyrene based macroporous cation exchange resin (D72) which was filled in the catalystic layers of the structured packings. The effects of operating parameters such as reflux ratio, total feed rate, molar ratio of methanol to formaldehyde, catalyst weight, aqueous formaldehyde concentration were studied experimentally. The appropriate operating parameters obtained in the present study include: reflux ratio is 5; total feed rate is 3.10. kg/h; molar ratio of methanol to formaldehyde is 2.5, catalyst weight is 0.51. kg, aqueous formaldehyde concentration is 35.3%. Under the above operating conditions the average conversion of formaldehyde is 99.6% while the average methylal purity is 92.1%. In order to achieve higher purity of methylal at the top of the column, two different configurations: feeding aqueous formaldehyde and feeding water at mid-way of rectifying section, was tried in the experiments. The experimental results show that the former configuration surpasses the latter, under which the average conversion of formaldehyde is 99.8% and the average methylal purity is 99.1%. © 2010 The Institution of Chemical Engineers. Source

Jia P.-F.,Tianjin Univtech Co. | Tang H.-D.,Tianjin Univtech Co. | Wang J.-H.,Tianjin Univtech Co. | Zeng A.-W.,Tianjin University
Huaxue Gongcheng/Chemical Engineering (China) | Year: 2013

The cyclohexanone was used as raw material in the industrial production technology of o-phenylphenol (OPP). The cyclohexanone was polycondensed in the presence of acid catalysts. In this reaction, water was removed by entrainer. The mixture of 2-(1-cyclohexenyl) cyclohexanone and 2-cyclohexyl alkylidene cyclohexanone was obtained through this reaction. The products were purified by high-efficiency distillation techniques, and the non-fully reacted cyclohexanone was recycled in the distillation process. After the purification, the dimers entered into the fixed-bed reactor with hydrogen as carrier gas, and the catalytic dehydrogenation reaction was carried out. The reaction products underwent the unit operations like high-efficiency distillation, recrystallization, drying and slicing. The mass fraction of finished product OPP can eventually achieve more than 99.5%. Source

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