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Qi J.-L.,Tianjin University | Gao Y.-J.,Tianjin Academy of Environmental science | Gao Y.-J.,Tianjin United Environmental Engineering Design Company Ltd | Chen R.-R.,Tianjin University
Chemical Papers | Year: 2016

As a novel process intensification technology, microwave-assisted continuous reaction distillation (MRD) was proposed for the esterification reaction and separation of ethyl acetate (EtOAc). The effects of reflux ratio, mole ratio of acetic acid (HOAc) to ethanol (EtOH), reboiler duty, microwave power on EtOH conversions, EtOAc purity and mass ratio of distillate to feed (D/F) were explored. In comparison with conventional heating, the experimental results revealed that the EtOAc purity in the distillate under microwave conditions (MC) was improved. Computer simulations for conventional and MRD systems were performed using the Aspen Plus non-equilibrium stage model to substantiate the experimental results. The model predictions are in good agreement with the experimental data, revealing the accuracy and reliability of the non-equilibrium model. This new MRD process can be an effective and productive method of ester production. © 2016 Institute of Chemistry, Slovak Academy of Sciences.


Ding H.,Tianjin University | Li J.,Tianjin University | Gao Y.,Tianjin Academy of Environmental science | Gao Y.,Tianjin United Environmental Engineering Design Company Ltd | And 5 more authors.
Powder Technology | Year: 2015

In order to reduce the release of hazardous waste silicon sludge (WSS) into the environment, we report a novel method to transform the WSS into silica nanoparticles and simultaneously to separate abrasive silicon carbide (SiC) particles. Alkali dissolution and acid precipitation processes were utilized to prepare silica nanoparticles effectively. The alkali dissolution process was carried out by sodium hydroxide to produce sodium silicate solution, from which SiC was separated by filtration. Afterward, the silica nanoparticles were prepared by acid precipitation method using hydrochloric acid. Box-Behnken design (BBD) was used to optimize the process variables affecting the dissolution efficiency, namely, mass ratio of NaOH and WSS, reaction temperature, and reaction time, and to determine the optimum conditions for the reaction process. Ultraviolet-visible spectrophotometer was used to measure the silica concentration in the solution. Characterized by XRD, FTIR, TEM, and BET surface area analysis, the silica with average pore size (10.52nm), high specific surface area (430.9m2/g) was obtained, and the particle size was about 20-45 nm. © 2015 Elsevier B.V.


Xu D.,Tianjin Academy of Environmental Science | Xu D.,Tianjin United Environmental Engineering Design Company Ltd | You Y.,Tianjin United Environmental Engineering Design Company Ltd | Li Y.,Chinese Research Academy of Environmental Sciences | Shi Y.,Tianjin United Environmental Engineering Design Company Ltd
Chinese Journal of Environmental Engineering | Year: 2015

Based on the technique of single phase particle image velocimetry (PIV), the PIV used to test gas-liquid two-phase flow field was studied. The information in different flowing phases was firstly masked, identified, extracted and calculated by using digital masking techniques, and the corresponding software was designed. Then, the two-phase flow field measurement in an ozone exposure reactor was investigated with the improved PIV method. The results showed that the axial velocity distribution of liquid phase is the dominant factor which decided hydraulic characteristics in the reactor; intake air flow rate directly affected the velocity distributions of the two-phase in the reactor. The axial velocity and lateral velocity of the two phases both increased with increasing intake air flow rate, meanwhile, the flow structure and its distribution of the reactor changed greatly. ©, 2015, Science Press. All right reserved.


Xu D.,Tianjin Academy of Environmental Science | Xu D.,Tianjin United Environmental Engineering Design Company Ltd | Bao H.,Chongqing Three Gorges University | Bao H.,Tsinghua University | Shi Y.,Tianjin United Environmental Engineering Design Company Ltd
Chinese Journal of Environmental Engineering | Year: 2015

The membrane deposits formation and growth model based on fractal theory were developed, it can dynamically describe the fouling process on outer surface of membrane. Using this model to change the boundary conditions and initial particle production chance, the process of membrane deposits formation and growth was simulated under different conditions. The micro-PIV technology was applied in membrane fouling observed experiment. Using Quantum dot fluorescent tracer, it was realized that membrane deposits morphology and its surrounding flow field were simultaneously observed and analyzed. The results of fractal dimensions were pretty much to be expected. It indicated that the relevant model of membrane deposits formation and growth were well exemplified in practice. The relevant model was used to simulate the impact of flow flied and suspended solids concentration on the dynamical variation of membrane deposits formation. ©, 2015, Science Press. All right reserved.


Ye W.,Tianjin University | Gao Y.,Tianjin Academy of Environmental science | Gao Y.,Tianjin United Environmental Engineering Design Company Ltd | Ding H.,Tianjin University | And 4 more authors.
Fuel | Year: 2016

In the present study, the kinetics of transesterification of palm oil was explored under conventional heating and microwave irradiation, using CaO as heterogeneous catalyst. The optimal experimental conditions were, microwave power of 150 W, alcohol to oil molar ratio of 9:1, catalyst of 5%, stirring speed of 450 r/min and reaction time of 60 min. By establishing kinetic models, the total reaction orders of transesterification under the two heating methods were figured out. The total reaction order under conventional heating was 1, while 3 under microwave irradiation, which indicated that microwave irradiation could increase the overall reaction order and accelerate the conversion rate for biomass to biodiesel. © 2016 Elsevier Ltd. All rights reserved.


Gao Y.,Tianjin Academy of Environmental science | Gao Y.,Tianjin United Environmental Engineering Design Company Ltd | Li X.,Tianjin University | Ding H.,Tianjin University
Waste Management | Year: 2015

A layer model was established to elucidate the mechanism of zinc removal from the metallic mixture of waste printed circuit boards by vacuum distillation. The removal process was optimized by response surface methodology, and the optimum operating conditions were the chamber pressure of 0.1 Pa, heating temperature of 923 K, heating time of 60.0 min, particle size of 70 mesh (0.212 mm) and initial mass of 5.25 g. Evaporation efficiency of zinc, the response variable, was 99.79%, which indicates that the zinc can be efficiently removed. Based on the experimental results, a mathematical model, which bears on layer structure, evaporation, mass transfer and condensation, interprets the mechanism of the variable effects. Especially, in order to reveal blocking effect on the zinc removal, the Blake-Kozeny-Burke-Plummer equation was introduced into the mass transfer process. The layer model can be applied to a wider range of metal removal by vacuum distillation. © 2015 Elsevier Ltd.


Yang Y.H.,Tianjin Polytechnic University | Bao J.L.,Tianjin Environmental Protection Bureau | Wen J.,Tianjin Academy of Environmental science | Li R.,Tianjin Academy of Environmental science | And 3 more authors.
Advanced Materials Research | Year: 2014

As the atmospheric environment pollution becoming more and more serious, analyzing and improving the atmospheric environmental quality is an important work. According to the atmosphere environment quality monitoring data of Tianjin, by adopting the combination of principal component analysis and linear regression method, this paper analyzes the influencing factors of major air pollutants (SO2, NO2 and PM10) on atmospheric environmental quality. © (2014) Trans Tech Publications, Switzerland.


Peng J.,Tianjin University | Pan J.,Tianjin United Environmental Engineering Design Co. | Xu J.,Tianjin University | Zhang W.-J.,Tianjin University
Huaxue Gongcheng/Chemical Engineering (China) | Year: 2011

Liquid-liquid extraction, phase separation with salt, azeotropic distillation were investigated for the separation of ternary heterogeneous azeotropic mixture of 2-ethoxy-ethanol, 4-methyl-2-pentanone and water (EC+MIBK+H2O). The result shows that the results of liquid-liquid extraction were not effective; phase separation with K2CO3 as isolates has good result but a large number of salt recovery make this method too difficult to be industrialized; azeotropic distillation with methyl isobutyl ketone as entrainer can get EC with mass fraction of 99.4% and MIBK with mass fraction of 99.2%, and has perfect future for industrialization.


Peng J.,Tianjin University | Pan J.,Tianjin United Environmental Engineering Design Co. | Xu J.,Tianjin University | Zhang W.-J.,Tianjin University
Huaxue Gongcheng/Chemical Engineering (China) | Year: 2011

The ternary heterogeneous azeotropic mixture of 2-ethoxy-ethanol, 4-methyl-2-pentanone and water was theoretically studied by the residue curve maps (RCM), the residue curve, the distillation boundary and the liquid-liquid equilibrium curve. Through process design, simulating and experimental validation, the separation process was set up. Five steps that were used to get 4-methyl-2-pentanone with mass fraction of 99.24%, 2-ethoxy-ethanol with mass fraction of 99.17%, and water with mass fraction of 98.52% were designed, including azeotropic distillation, phase condensed, partial reflux of oil phase, recovery of heavy components, recovery of light components. The experimental results are highly coinciding with the simulation results, which can ensure good industrial prospects of the separation process.


Ding H.,Tianjin University | Gao Y.,Tianjin Academy of Environmental science | Gao Y.,Tianjin United Environmental Engineering Design Company Ltd | Li J.,Tianjin University | And 4 more authors.
Journal of Chemical and Engineering Data | Year: 2016

The vapor-liquid equilibrium (VLE) data for the binary system isopropyl alcohol + dimethyl sulfoxide (DMSO), isopropyl acetate + DMSO, and ternary system isopropyl alcohol + isopropyl acetate + DMSO were measured with a VLE modified Othmer still at 101.3 kPa. The experimental data were proved to be thermodynamically consistent when the point-to-point consistency test of Van Ness test was applied. The binary experimental data were correlated with the nonrandom two-liquid (NRTL), Wilson, and universal quasichemical (UNIQUAC) activity coefficient models. Then, the ternary VLE data were predicted with the obtained binary interaction parameters. The results indicate that the values of equilibrium temperature and vapor mole fraction calculated by the NRTL, Wilson, and UNIQUAC models are in good agreement with the experimental data. When the mole ratio of the binary azeotrope to DMSO was 1:1.5, the binary azeotrope of isopropyl alcohol and isopropyl acetate was eliminated. Therefore, DMSO is a potential extractive agent to separate the azeotrope by extractive distillation. © 2016 American Chemical Society.

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