Wang Z.,Tianjin University |
He S.,Tianjin Municipal Engineering Design and Research Institute |
Li J.,Tianjin Municipal Engineering Design and Research Institute |
Song G.,China Tianchen Engineering Corporation
Advanced Materials Research | Year: 2012
Trilateral Flash Cycle (TFC) is particularly suitable for recovering energy from low-grade heat source. This paper presented a new mathematical model for calculating the performance of a twin screw expander integrated into a TFC working with organic components. The geometric parameters related to the rotation angle of male rotor e.g. groove volume, suction and discharge port area, leakage area etc were used in the model. The combination effects of internal leakage through five paths, oil injection, gas-oil heat transfer and refrigerant property were taken into account. The sensitivity of single parameter was also analyzed. To verify the model and the calculated p-φ indicator diagram, experimental recording of the diagram of twin screw expander was performed. The results of theoretical calculation were in good agreement with the experimental data, which indicated that the model in the present paper could be used as a powerful tool for performance prediction and product development.
Wang J.,Tianjin Polytechnic University |
Xu J.,China Tianchen Engineering Corporation |
Meng X.,Tianjin University |
Huang Y.,Tianjin University
Materials Research Bulletin | Year: 2014
Nanolamellar Fe3O4 (magnetite) (NLM) was synthesized by template method. The repeat periodicity of the 2-dimensional nanolamellar structure was 3.72 nm. NLM exhibited a superparamagnetic characteristic with the saturated magnetization 34.8 emu/g. The results showed NLM possessed properties of novel microwave absorption in the frequency range 1-18 GHz. An obvious multiple-reflection loss phenomenon was observed with the increase of matching thickness. For example, 8 reflection loss peaks could be found on the reflection loss curve of NLM/paraffin composite with 50 wt.% NLM at the thickness of 28.0 mm. Compared with NLM/paraffin composite with 75 wt.% NLM, the microwave absorption property of the composite with 50 wt.% NLM was confirmed to be inferior in the 1-10 mm thickness range but superior in the 10-30 mm thickness range. The lowest reflectivity was -46.6 dB obtained from NLM/paraffin composite with 75 wt.% NLM at 7.0 mm thickness. The NLM is a promising microwave absorber. © 2013 Elsevier Ltd. All rights reserved.
Qi J.,Tianjin University |
Lv W.,Tianjin University |
Lv W.,China TianChen Engineering Corporation |
Zhang G.,Tianjin University |
And 3 more authors.
Nanoscale | Year: 2013
We have successfully developed a unique graphene-based smart catalytic system which consists of the graphene supported Au-Pt bimetallic nanocatalyst with a well-defined core-shell structure and a dextran-based temperature-responsive polymer. The unique catalytic system possesses excellent catalytic performances and the catalytic activities could be readily switched on or off at different temperature windows. © 2013 The Royal Society of Chemistry.
Zhang H.,China Tianchen Engineering Corporation |
Song H.,Northeast Forestry University
Industrial and Engineering Chemistry Research | Year: 2012
Adsorptive denitrogenation of model fuel and commercial diesel containing organic nitrogen compounds was studied over three typical mesoporous molecular sieves (Ti-HMS, HMS, and MCM-41) in a fixed-bed adsorption system at ambient pressure. The adsorbents were characterized by X-ray diffraction, UV-visible spectroscopy, transmission electron microscopy, N2 physical adsorption-desorption, and temperature-programmed NH3 desorption techniques. The adsorption capacities for various compounds (pyridine, quinoline, pyrrole, and indole) were examined and compared on the basis of the breakthrough curves, which provided insight into the adsorption behaviors over the different adsorbents. It is shown that the breakthrough time is shortened at increased temperature and liquid hourly space velocity (LHSV). The adsorption performance of HMS and Ti-HMS depends dominantly on the acid-base interaction. In addition, the polarity of the adsorbate is another factor that influences the adsorption capacity. The introduction of Ti improves the acidity of Ti-HMS, which thus exhibits a higher adsorption capacity than HMS, as confirmed by UV-visible spectroscopy and temperature-programmed NH3 desorption. The adsorption performance of nonacidic MCM-41 depends principally on the molecular weight of the adsorbate. For commercial diesel, the adsorption competition between sulfur and nitrogen compounds influences the adsorption of total nitrogen. © 2012 American Chemical Society.
Lu K.,Hebei University of Technology |
Li R.,Hebei University of Technology |
Wu Z.,Hebei University of Technology |
Hou K.,Hebei University of Technology |
And 2 more authors.
Separation and Purification Technology | Year: 2013
A novel and structurally simple foam separation column with the cross internal was developed for investigating the effect of the column wall on the drainage of rising foam, using sodium dodecyl sulfate (SDS) as a foam agent. The cross internal enhances significantly wall effect due to an increase of wall contact area in the foam phase. Furthermore, the performances of foam separation column with the cross internal were assessed using crystal violet (CV) as the model system and SDS as the collector. The insertion of the cross internal significantly decreased the liquid holdup of the foam out of the column and increased the bubble size. The results showed that an increase in wall contact area in the foam phase could enhance the drainage of rising foam due to the higher drainage velocity between the bubbles and the column wall than that between the adjacent bubbles. Under the suitable operations conditions, the enrichment ratio of CV was 16.5 by using the column with the cross internal and it was nearly four times higher than the column without the cross internal. The better performances indicated that an increase of wall contact area in the foam phase is a simple and effective method to enhance foam drainage and improve enrichment of foam separation. © 2013 Elsevier B.V. All rights reserved.
Chen S.-H.,China Tianchen Engineering Corporation
Xiandai Huagong/Modern Chemical Industry | Year: 2013
The principle, process flow and technology features of two kinds of nitrogen producing processes of PSA and cryogenic separation, are introduced. The technology features, investment, land area, etc., are compared comprehensively. The application principle of two kinds of technology is pointed out in the end.
Sun H.-J.,Zhengzhou University |
Wang H.-X.,Zhengzhou University |
Jiang H.-B.,Zhengzhou University |
Li S.-H.,Zhengzhou University |
And 4 more authors.
Applied Catalysis A: General | Year: 2013
A series of Ru-Zn catalysts with different Zn contents were prepared by co-precipitation. The catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES)-Ar+ sputter, transmission electron micrographs (TEM)-energy dispersion scanning (EDS) and temperature-programmed reduction (TPR). The performances of the catalysts for benzene selective hydrogenation to cyclohexene were investigated in the presence of 0.6 mol/L of ZnSO4. The results showed that the Ru and Zn in Ru-Zn catalyst were in metallic Ru and ZnO respectively and the ZnO was rich on the surface. The ZnO alone could not improve the selectivity to cyclohexene of Ru-Zn catalyst. However, the ZnO on the surface could react with ZnSO4 to form a (Zn(OH) 2)3(ZnSO4)(H2O)5 salt. The (Zn(OH)2)3(ZnSO4)(H2O) 5 salt chemisorbed played a key role in improving the selectivity to cyclohexene of Ru-Zn catalysts. After Ru-Zn(8.6%) catalyst was pretreated 22 h in ZnSO4 solution at 140 °C and 5 MPa H2, a cyclohexene selectivity of 81.4% at a benzene conversion of 54.0% was achieved at 10 min and a maximum cyclohexene yield of 58.9% was reached. Moreover, the activity was stable above 50% and the cyclohexene selectivity and yield were steadily above 76% and 40% on this catalyst in the first six recycles, respectively. © 2012 Elsevier B.V.
Sun Q.,China University of Petroleum - Beijing |
Chen G.,China TianChen Engineering Corporation |
Guo X.,China University of Petroleum - Beijing |
Liu A.,China University of Petroleum - Beijing
Fluid Phase Equilibria | Year: 2014
Hydrate separation technology has been widely applied to the separation of various gas mixtures with its own unique advantages over the past several decades. However, so far the relevant studies seem to be elementary and exploratory, and most of the separation processes are batch-type and not appropriate of practical uses. To promote the development of hydrate separation technology and to realize its industrial application early, we systematically investigated the continuous separation of CH4-N2, CH4-H2 and CO2-N2 gases respectively by hydrate method using 6mol% tetrahydrofuran (THF) solution as the liquid medium in this work. The results demonstrate that the continuous process of sequential hydrate formation and dissociation can be achieved in the presence of THF under appropriate temperatures and pressures, and the gas mixtures can be separated to some extent after liquid absorption and hydration reaction. The continuous separation process in this work provides an achievable approach for the application of hydrate separation method. © 2013 Elsevier B.V.
Xue Z.-Y.,China Tianchen Engineering Co.
Xiandai Huagong/Modern Chemical Industry | Year: 2014
The present situation of soil pollution and its special characteristics in China is introduced. The soil remediation technologies in U. S and Europe are enumerated and compared. For China, the soil remediation is only in the beginning and without any ripe experience up to know. Therefore, only a few of typical demonstrations for soil remediation are introduced. These illustrative examples will be spread after obtaining the successful experiences. In the end, some suggestions for soil remediation are proposed.
Wang L.,Southern Illinois University Carbondale |
Williams J.I.,Southern Illinois University Carbondale |
Lin T.,Southern Illinois University Carbondale |
Lin T.,China Tianchen Engineering Corporation |
Zhong C.-J.,Binghamton University State University of New York
Catalysis Today | Year: 2011
Reduction of O2 in the presence of model PtVFe nanocatalysts was studied using the PBE functional with a plane wave basis set. The model catalysts consisted of trimers and a 0.6-nm particle. The results show that among three molecular chemisorption configurations, i.e. Pauling, Griffith, and Yeager configurations, the O2 bond is weakened the most in the Yeager configuration, then the Griffth configuration, and then the Pauling configuration. A new molecular chemisorption configuration, i.e. 5-atom ring configuration, was also identified. With the O-O distance up to 1.4 , a linear correlation was found between the O2 stretching frequency and the O2 bond distance regardless of the metal or adsorption site. However, the charge transfer and the adsorption energy are highly dependent on the metal and adsorption site. The alloyed clusters are most effective in transferring electrons to O2 species and weakening O2 bond especially when the O atoms are attached to non-Pt atoms. Our results suggest that the superior catalytic activity of PtVFe nanoparticles in the oxygen reduction is due to the effectiveness in charge transfer and the presence of direct (spontaneous) dissociation pathway. © 2011 Elsevier B.V. All rights reserved.