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Zhang X.-B.,Zhejiang University | Chen J.-Y.,Zhejiang University | Yao L.,Hangzhou Hangyang Co. | Huang Y.-H.,Shanghai JiaoTong University | And 2 more authors.
Journal of Zhejiang University: Science A | Year: 2014

With the rapid growth in demand for industrial gas in steel and chemical industries, there has been significant emphasis placed on the development of China's large-scale air separation technology. Currently, the maximum capacity of a single unit has been able to attain 120 000 Nm3/h (oxygen), and the specific power consumption of 0.38 kWh/m3. This paper reviews the current state-of-the-art for large-scale cryogenic air separation systems being deployed in China. A brief introduction to the history and establishment of the large-scale cryogenic air separation industry is presented. Taking the present mainstream large-scale air separation unit operating at 60 000 Nm3/h (oxygen) as an example, the technological parameters and features of the involved key equipment, including a molecular sieve adsorber, air compressor unit, plate-fin heat exchanger, turbo-expander and distillation column are described in detail. The developing 80 000-120 000 Nm3/h air separation processes and equipment are also introduced. A summary of the existing problems and future developments of these systems in China are discussed. © Zhejiang University and Springer-Verlag Berlin Heidelberg 2014. Source


Liu J.,Zhejiang University | Zhang S.,Zhejiang University | Zhou Z.,Hangzhou Hangyang Co.
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2015

The effect of fluid flow and heat transfer caused by fins in plate-fin heat exchanger is investigated, and then a new kind of fins, called shark gill fin, is proposed. The main functions of this kind of fins include enlarging fluid turbulence effect, changing flow direction in the same layer of fins, promoting fluid flow among channels, decreasing fluid temperature difference in the same cross-section and finally promoting heat exchange efficiency. The temperature, velocity, pressure and turbulence field under twelve conditions are analyzed by changing cocking-up structure and opening size in shark gill fin and finally, the distribution of fluid flow, temperature, dynamic pressure and turbulent intensity under steady state conditions are achieved. It can be concluded that when the opening size is 1 mm, the fluid velocity difference can reach by 47.38%, the temperature difference can reach by 0.7 ℃/m, the turbulent intensity difference can reach by 0.816%. When cocking-up structure is 10°, the fluid turbulent intensity can reach by 3.162%, the temperature difference can reach by 1 ℃/m. The results demonstrate that, in view of fluid flow, the effect of opening size is more important than cocking-up degree while, in view of temperature field, the opening size is less important than the cocking-up degree, besides, the cocking-up degree has less effect on fluid velocity and dynamic pressure. ©, 2015, Journal of Mechanical Engineering. All right reserved. Source


Deng H.,Zhejiang University of Technology | Zhang S.,Zhejiang University of Technology | Zheng Y.,Hangzhou Hangyang Co.
Paiguan Jixie Gongcheng Xuebao/Journal of Drainage and Irrigation Machinery Engineering | Year: 2012

To establish a basic theory system and design method for a new type of annular U-diaphragm in hydraulic diaphragm pumps, the relation between U-diaphragm deflection and deformation quantity was analyzed by using the nonlinear analysis function in finite element software Ansys. A thin, hollow, double shell U-diaphragm finite element model with geometry and material nonlinear character was established for the annular U-diaphragm used in the prototype of hydraulic diaphragm pump. The deflection of the U-diaphragm model was analyzed under different compression and stretch displacements when the displacements of the supported end were fixed, the displacements of the free supported end were prescribed and the pressure loads were applied on both sides of the U-diaphragm. The computed displacements of deflection were fitted by using differential evolution method where the correct fitting curves were determined by controlling mean square error and correlation coefficient and so on. The U-diaphragm movement was clarified and an empirical relation for the deflection was obtained, eventually a theoretical formula for camber working volume was given. All the results above will provide a theoretical basis for working mechanism and design optimization of an annular U-diaphragm. Source


Shi P.,Zhejiang University | Wang Q.,Hangzhou Hangyang Co. | Xu Y.,Zhejiang University | Luo W.,Zhejiang University
Materials Letters | Year: 2011

Corrosion behavior of copper bulk with grain size of 48 nm prepared by inert gas condensation and in situ warm compress (IGCWC) technique was investigated in 0.3 wt.% ammonia solution. The nanocrystalline (NC) Cu sample displayed an active-passive-transpassive behavior with the formation of duplex passive films but without stable passive regions in potentiodynamic polarization process. NC Cu exhibited slightly inferior corrosion resistance when compared with coarse-grained (CG) Cu. It could be explained by both the higher grain boundary density that could accelerate corrosion reactions and the loose passive film formed on the surface of NC Cu that couldn't provide effective protection. © 2010 Elsevier B.V. All rights reserved. Source


Luo W.,Zhejiang University | Xu Y.,Zhejiang University | Wang Q.,Hangzhou Hangyang Co. | Shi P.,Zhejiang University | Yan M.,Zhejiang University
Corrosion Science | Year: 2010

Effect of grain size on corrosion of bulk nanocrystalline copper was investigated using potentiodynamic polarization measurements in 0.1. M NaOH solution. Bulk nanocrystalline copper was prepared by inert gas condensation and in situ warm compress (IGCWC) method. The grain sizes of all bulk nanocrystalline samples were determined to be 48, 68 and 92. nm using X-ray diffraction (XRD). Results showed that bulk coppers displayed an active-passive-transpassive behaviour with duplex passive films. From polycrystalline to nanocrystalline, grain size variation showed little effect on the overall corrosion resistance of copper samples. © 2010 Elsevier Ltd. Source

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