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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.


Zhang X.,Tianjin University | Zuo J.,Tianjin University | Jian C.,Tianjin Univtech Co.
Journal of Chemical and Engineering Data | Year: 2010

Isobaric vapor-liquid equilibrium (VLE) data were measured for the binary systems ethyl methyl carbonate (EMC) + methanol, + ethanol, + dimethyl carbonate (DMC), and + diethyl carbonate (DEC) at 101.3 kPa using a vapor-liquid equilibrium still. The thermodynamic consistency of the experimental data was verified by Herington(1)method. The experimental VLE data were correlated with the Wilson, NRTL, and UNIQUAC activity coefficient models. The results show that the calculated values of vapor phase mole fraction and boiling temperature by the Wilson, NRTL, and UNIQUAC models agree well with the experimental data. Futhermore, azeotropic behavior was observed for the binary system of ethanol + EMC. © 2010 American Chemical Society.


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.


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.


Wang Y.,Tianjin University | Ma H.,Tianjin University | Zhu H.,Tianjin Univtech Co. | Tang W.,Sinopec
Advanced Materials Research | Year: 2012

As a combination of divided wall column (DWC) and reactive-distillation column, the reactive divided wall distillation column is a highly complex technology that reaction and separation can occur simultaneously, which can reduce the energy consumption and decrease the costs of captial and operation. This new process was simulated with PRO II software and mini plant experiments were implemented. In addition, we investigated the influences of reflux ratio, liquid distribution ratio and molar ratio of ester in water on the conversion rate of methyl acetate and the purity of the product respectively. It could be seen that the trend from experiments was suitable with simulation results. © (2012) Trans Tech Publications.


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.


Lu H.,Nankai University | Wang J.,Nankai University | Bu S.,Langfang Dayuan Chemical Co. | Zhang M.,Tianjin Univtech Co. | Zhang J.,Tianjin Univtech Co.
Advanced Materials Research | Year: 2011

The aim of the present work was to study the effect of properties of ion exchange membrane on separation performance of electrodeionization (EDI) process for removal of nickel ions from dilute heavy metal solutions. It was shown that the properties of ion exchange membrane had a significant effect on removal of nickel ions. With feed water containing nickel ions at the concentration of 55mg·L-1, the nickel ions concentration of dilute stream was lower than 0.5mg·L-1 and the nickel rejection was greater than 99% when using EDI membranes, while that was in the range of 2.48-3.55mg·L-1 with conventional heterogeneous ion exchange membranes. With optimum ion exchange material and operating conditions, EDI would be a very interesting and innovative technology for the treatment of dilute heavy metal solutions. © (2011) Trans Tech Publications.


Zhao R.-W.,Tianjin Univtech Co. | Cheng J.,Tianjin Univtech Co. | Tian G.-L.,Tianjin Univtech Co.
Huaxue Gongcheng/Chemical Engineering (China) | Year: 2013

In order to simplify the fluid mechanics calculation of two-stage trough liquid distributor in large-scale packing tower and further increase its operating uniformity and flexibility, a new design method named unequal liquid level method was put forward after equal liquid level method, which is widely known. Setting that the holes diameter of stage I trough was twice of the stage II trough and the orifice flow coefficients were equal, the mass balance of stage II trough was done by using the hydraulic formula for the liquid rate through small holes. It shows that the number of holes on stage I trough is proportional to that of stage II when the ratio of liquid levels in stage I trough and stage II trough is a specific value. Then the number, complement number and diameters of holes on stage I trough can be got through the number of holes on each stage II trough. The equal liquid level method for trough liquid distributor design is applied for many years and the unequal liquid level method is being developed and applied.


The invention discloses a dual-flow-baffle compound gasoline fractionator of ethylene unit, a quench oil circulation section is provided with micro baffles which are arranged in parallel in the vertical direction at intervals, a vertex angle of the micro baffle ranges from 90 to 139 degrees, symmetrical bevel edges at two sides of the vertex angle of the micro baffle are provided with symmetrical vertical hems, a medium oil circulation section is provided with dual-flow trays which are arranged in the vertical direction and have meshes with the diameter ranging from 18 to 24mm, a diesel oil separation section is provided with dual-flow trays which are arranged in the vertical direction and have meshes with the diameter ranging from 13 to 24mm, and a gasoline separation section is provided with dual-flow trays which are arranged in the vertical direction and have meshes with the diameter ranging from 13 to 18mm. The gasoline fractionator overcomes the frequent problem of polymer plugging in current plate-type fractionator, and has the prominent advantages of strong impact vibration resistance, reduced pressure of entire tower, high ethylene yield, outstanding energy-saving effect and being capable of ensuring long-term stable operation of this tower.


Patent
Tianjin Univtech Co. | Date: 2013-02-06

The invention discloses a space truss support device in a large-scale tower, the large-scale tower is provided with a foundation beam therein, pillars are distributed on the surface of the foundation beam at intervals, both layering and horizontal support of X-direction cross beams and Y-direction cross beams are realized between the pillars and between the pillars on the periphery and a tower body, and the X-direction cross beams and the Y-direction cross beams of all layers horizontally support functional members inside the tower respectively. The device consisting of the foundation beam, the pillars, the X-direction cross beams and the Y-direction cross beams has the characteristics of large intensity, good rigidness and small flexibility, in particular, the multi-pillar structure of the device achieves the division of the existing large-span long cross beam into small-span short cross beams, thus high levelness of tower tray can be guaranteed. With strong resistance to the impact of high-speed variable gas load, the device can effectively avoid the vibration accident caused by the impact, and in particular, a baffle in the structure is a segmental short baffle so as to avoid resonant vibration owing to the impact and guarantee long-term stable operation of the tower. The invention has the prominent advantages of reducing the manufacturing and installation difficulty as well as the investment of tower support device.

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