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Peng Z.,Jiangsu Frontier Electrical Technology Co. | Zhong L.,Nanjing University of Science and Technology | Li H.,Nanjing University of Science and Technology | Zhang S.,Nanjing University of Science and Technology | Zhong Q.,Nanjing University of Science and Technology
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

In view of the limitations of low-temperature catalysts about MnOx/TiO2, based on the theory of superoxide free radical in the field of photocatalysis, this study proposed a new way for N-doped catalyst by nonmetal materials. N-doped MnOx/TiO2 catalyst with good activity under low temperature was prepared by sol-gel method for titania support, followed by impregnation for MnOx loading. N doping, Mn loading and calcination temperature of the N-doped catalyst were optimized and the results were analyzed by XRD. Based on these results, the effects of O2 concentration, [NH3]/[NO] and GHSV were investigated. The experimental results show that when the reacting mixture contains 5% O2, [NH3]/[NO]=1.2 and GHSV=28000 h-1, the NO conversion of the N-doped MnOx/TiO2 catalyst with 1% N doping and 5% Mn loading is about 90% over 180°C. © 2013 Chinese Society for Electrical Engineering.

Wei Y.,Henan Polytechnic University | He Q.,Qingdao Technological University | Sun Y.,Hohai University | Sun Y.,Henan Polytechnic University | Ji C.,Jiangsu Frontier Electrical Technology Co.
Mathematical Problems in Engineering | Year: 2013

Voltage source converter (VSC) based high-voltage direct-current (HVDC) system is a new transmission technique, which has the most promising applications in the fields of power systems and power electronics. Considering the importance of power flow analysis of the VSC-HVDC system for its utilization and exploitation, the improved power flow algorithms for VSC-HVDC system based on third-order and sixth-order Newton-type method are presented. The steady power model of VSC-HVDC system is introduced firstly. Then the derivation solving formats of multivariable matrix for third-order and sixth-order Newton-type power flow method of VSC-HVDC system are given. The formats have the feature of third-order and sixth-order convergence based on Newton method. Further, based on the automatic differentiation technology and third-order Newton method, a new improved algorithm is given, which will help in improving the program development, computation efficiency, maintainability, and flexibility of the power flow. Simulations of AC/DC power systems in two-terminal, multi-terminal, and multi-infeed DC with VSC-HVDC are carried out for the modified IEEE bus systems, which show the effectiveness and practicality of the presented algorithms for VSC-HVDC system. © 2013 Yanfang Wei et al.

Wang H.,Jiangsu Frontier Electrical Technology Co. | Jiang Y.,Nanjing University of Aeronautics and Astronautics
Mathematical Problems in Engineering | Year: 2013

Complex system performance reliability prediction is one of the means to understand complex systems reliability level, make maintenance decision, and guarantee the safety of operation. By the use of complex system condition monitoring information and condition monitoring information based on support vector machine, the paper aims to provide an evaluation of the degradation of complex system performance. With degradation assessment results as input variables, the prediction model of reliability is established in Winer random process. Taking the aircraft engine as an example, the effectiveness of the proposed method is verified in the paper. © 2013 Hongxing Wang and Yu Jiang.

Xu H.,Jiangsu Frontier Electrical Technology Co.
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2011

The mechanism of Oxygenated Treatment (OT)-induced exfoliation of duplex scale in steam path can be interpreted with Ecocide Hypothesis, of which the core ideas are: the inner iron/chromium-mixed oxide layer in the duplex scale reacts with high-temperature steam to form gaseous Croxyhydroxides, which subsequently lead to obvious rise of cation conductivity. Cavities form at the interface of duplex scale due to reactive evaporation of Cr from the scale, and with the growth of cavity, the bond strength at interface drops gradually, thus the catastrophic exfoliation of duplex scale will inevitably happen. Ecocide Hypothesis may not only explain the mechanism of OT-induced exfoliation of duplex scale in steam path, but also help to predict the risk of OT. Greater risk will be created with the elongation of time duration from boiler commissioning to OT, with the rise of oxygen content in steam and with the improvement of steam parameters. To avoid the risk of exfoliation, OT should be synchronously scheduled in commissioning.

Hong A.X.,Jiangsu Frontier Electrical Technology Co.
ICOPE 2015 - International Conference on Power Engineering | Year: 2015

Based on Ecocide hypothesis, the theories about the exfoliation of duplex scale in steam path had been elaborated. The causes which induced exfoliation of duplex scale could be divided into two types: internal and external factors. The former was the number and scale of voids existed in the inner and outer layer interface nearby, and the latter was the total stress response of scale. Furthermore, the internal and external causes by which the voids mentioned above might be affected were respectively chromium content of steel and steam conditions. In superheated steam, oxygen content bears pronounced correlation with chromate content. Superheated steam cation conductivity could serve as the characteristic index of the chromia evaporation of scale under the impact of oxygen in steam. The inner layer would continue to increase in thickness after exfoliation of outer layer, but hard to flake off then. In this case, supercritical units that had suffered thorough exfoliation would be relatively safe, without a worry about spalling for a long period of time. © 2015 The Japan Society of Mechanical Engineers.

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