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Zhou L.,China Agricultural University | Xu H.,Zhejiang Zhongshui Hydropower Equipment Co. | Cui T.,China National Water Resources and Electrical Power Materials and Equipment Co. | Wang Z.,Tsinghua University
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2011

The rehabilitation projects have a huge market in China. In these projects, the flow rates of the turbines are always increased to increase the output. Since the buried parts and the rotational speed keep unchanged, the increase of flow rate will raise hydraulic loss in the whole flow path, thus may decrease the efficiency. In this paper, the hydraulic losses in spiral casing, stay vanes and guide vanes and their effects on the output and efficiency are analyzed. A method is proposed to evaluate the flow rate and guide vane opening for the refurbished turbines. As an example, the hydraulic losses in buried parts of a real case are calculated through flow simulations and the efficiency of the refurbished turbine is evaluated based on these results. Modification of the guide vane profile is suggested for higher efficiency with less flow rate increase. © Copyright.


Zheng S.-Z.,China National Water Resources and Electrical Power Materials and Equipment Corporation | Yin J.-P.,China National Water Resources and Electrical Power Materials and Equipment Corporation | Xiong Y.-Q.,Nanjing Southeast University | Xie H.-Y.,Nanjing Southeast University | Shi Z.-F.,Nanjing Southeast University
Ranshao Kexue Yu Jishu/Journal of Combustion Science and Technology | Year: 2011

Mass transfer of NO x in the liquid phase was analysed. Using three different absorbents made of urea and ammonium, wet denitrification was investigated in sprinkling absorption reactors filled with steel pall rings. A series of experiments were carried out to study operation parameters, such as gas velocity, ratio of liquid to gas, absorbent concentration, gas temperature, absorbent temperature, additive concentration, NO x concentration and SO 2 existence. The experimental results indicated that urea solution was more efficient in NO x removal than ammonium ion solution. At the same time, gas velocity, ratio of liquid and gas, system temperature, additive concentration and NO x concentration had great effects on the removal efficiency of NO x from flue gas. When 2000 × 10 -6 SO 2 was added, the efficiency of denitrification was improved by 5%, which showed that there existed a mutual promotion effect of SO 2 and NO x in the same system.


Yan Z.G.,China Agricultural University | Cui T.,China National Water Resources and Electrical Power Materials and Equipment Co. | Zhou L.J.,China Agricultural University | Zhi F.L.,China Agricultural University | Wang Z.W.,Tsinghua University
IOP Conference Series: Earth and Environmental Science | Year: 2012

Hydroelectric generator unit is a complex mechanical system which is composed of hydraulic turbine and electric generator. Rotary system is supported by the bearing bracket and the reinforced concrete structures, and vibration problem can't be avoided in the process of operating. Many large-scale hydroelectric units have been damaged because of the vibration problem in recent years. As the increase of the hydraulic turbine unit capacity and water head, the safe operation of hydraulic turbine has become a focus research in many countries. The operating characteristics of the hydraulic turbine have obvious differences at different working conditions. Based on the combination of field measurement and theoretical calculation, this paper shows a deep research on the safe operation of a large-scale Francis turbine unit. Firstly, the measurements of vibration, swing, pressure fluctuation and noise were carried out at 4 different heads. And also the relationships between vibrations and pressure fluctuations at different heads and working conditions were analysed deeply. Then the scientific prediction of safe operation for the unit at high head were done based on the CFD numerical calculation. Finally, this paper shows the division of the operating zone for the hydroelectric unit. According to the experimental results (vibrations, swings, pressure fluctuations and noise) as well as the theoretical results, the operating zone of the unit has been divided into three sections: prohibited operating zone, transition operating zone and safe operating zone. After this research was applied in the hydropower station, the security and economic efficiency of unit increased greatly, and enormous economic benefits and social benefits have been obtained. © Published under licence by IOP Publishing Ltd.


Xie H.,Nanjing Southeast University | Xiong Y.,Nanjing Southeast University | Zheng S.,China National Water Resources and Electrical Power Materials and Equipment Corporation | Shi Z.,Nanjing Southeast University | Zhang J.,Nanjing Southeast University
Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University | Year: 2011

The ammonia/urea solution wet desulfurization and denitrification technology has low denitration efficiency in industrial application. In this study, the performance of simultaneous removal of SO 2 and NO x by the aqueous urea/ammonium ion/additive solution in a bubbling reactor was investigated, and the ions concentration and pH values of the solution after absorption was analyzed. The results show that the oxidation of NO by O 2 in the gas phase is the dominant mechanism of NO x removal by the aqueous urea/ammonium ion solution. The additive has no catalytic effect on NO absorption without the presence of O 2, and the presence of SO 2 promotes the NO absorption. The experimental results indicate that the reaction mechanism and the effect concerning NO removal by various additives are different. The alkanolamines additive has buffer and catalytic effects, and the mixing alkanolamines additive works better. However, the SO 2 absorption is in competition with the NO removal in the aqueous urea solution with KMnO 4. Under the experimental condition, the NO removal efficiency is lowest in the ammonia/water solution, and highest in the urea solution. The urea could prevent the nitrous acid from decomposing into NO, and the pH of the absorption solution decreases obviously while adding ammonium bicarbonate, which is unfavourable to NO x removal.


Xiao Y.X.,Tsinghua University | Cui T.,China National Water Resources and Electrical Power Materials and Equipment Co. | Wang Z.W.,Tsinghua University | Yan Z.G.,Tsinghua University
IOP Conference Series: Earth and Environmental Science | Year: 2012

Different from the reaction turbines, the hydraulic performance of the Pelton turbine is dynamic due to the unsteady free surface flow in the rotating buckets in time and space. This paper aims to present the results of investigations conducted on the free surface flow in a Pelton turbine rotating buckets. The unsteady numerical simulations were performed with the CFX code by using the Realizable k-ε turbulence model coupling the two-phase flow volume of fluid method. The unsteady free surface flow patterns and torque varying with the bucket rotating were analysed. The predicted relative performance at five operating conditions was compared with the field test results. The study was also conducted the interactions between the bucket rear and the water jet. © Published under licence by IOP Publishing Ltd.


Wang J.-X.,North China Electrical Power University | Wu Z.-Q.,China National Water Resources and Electrical Power Materials and Equipment Co. | Han Z.-H.,North China Electrical Power University | Liu X.-Z.,Handan College | Qian J.-B.,North China Electrical Power University
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2012

Taking the actual reaction process of fossil fuel as an object of study, a calculation formula of chemical exergy was derived for fuels containing a number of elements, such as C, H, O, N, S, etc., based on actual combustion process models and high heating values. With the formula, chemical exergy of some domestic coals was calculated and compared with that of overseas calculation results based on models for pure substance. Results show that the calculated values of chemical exergy obtained by the newly derived formula based on high heating values agree well with that of other researchers.


Wu Z.-Q.,North China Electrical Power University | Wu Z.-Q.,China National Water Resources and Electrical Power Materials and Equipment Co. | Zhou S.-X.,North China Electrical Power University | An L.-S.,North China Electrical Power University
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2011

To meet the strategy demand of energy structural adjustment and configuration optimization, and based on the second law of thermodynamics, influence of fuel quality on the second law efficiency by thermodynamics was analyzed, while fuel exergy of typical energy resources analyzed and evaluated. Results show that the higher the fuel quality (exergy) is, the less the fuel will be consumed for power generation. Standard coal coefficients of different fuels based on the second law of thermodynamics are presented, which may serve as a theoretical foundation for adjustment and configuration optimization of energy structure.


Wu Z.,North China Electrical Power University | Wu Z.,China National Water Resources and Electrical Power Materials and Equipment Co. | Zhou S.-X.,North China Electrical Power University | An L.-S.,North China Electrical Power University | Shi H.-L.,North China Electrical Power University
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2010

Based on previous studies, factors influencing the decision-making process of energy saving and emission reduction are analyzed at three levels, while three typical production patterns of energy-consuming products simultaneously discussed, with focus on statistics method and analysis model of their specific fuel consumption. Moreover, an evaluation on various methods of energy saving and emission reduction is made on the basis of specific fuel consumption of relevant end products. This may serve as a reference for scientifically building evaluation systems of energy saving and emission reduction.


Liu M.-H.,North China Electrical Power University | Wu Z.-Q.,North China Electrical Power University | Wu Z.-Q.,China National Water Resources and Electrical Power Materials and Equipment Co. | Han Z.-H.,North China Electrical Power University
Hydraulic Engineering - Proceedings of the 2012 SREE Conference on Hydraulic Engineering, CHE 2012 and 2nd SREE Workshop on Environment and Safety Engineering, WESE 2012 | Year: 2013

Based on the hypothesis that the average sulfur content rate of energy used in the same area remains unchanged or change can be ignored in the short term, the SO2 emission factor in each industrial sector and the average sulfur content rate of coal used in each province in China are calculated by the regression of the statistical data of sulfur-containing energy usage and SO2 emission, and a correction method for calculating the SO 2 emission factor in each province is put forward. Finally, the SO2 emission factor of each industrial sector in Beijing is calculated by the correction method and the accuracy of the SO2 emission factor modified is verified with the energy statistical data in each sector in Beijing. © 2013 Taylor & Francis Group.


Zhou S.-X.,North China Electrical Power University | Jiang Y.-Y.,North China Electrical Power University | Wu Z.-Q.,North China Electrical Power University | Wu Z.-Q.,China National Water Resources and Electrical Power Materials and Equipment Co. | And 3 more authors.
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2012

Based on the theory of unit consumption analysis and taking the heat loads of various boiler heat surfaces as different heat products, a complete unit consumption analysis model has been set up by studying following three irreversible thermodynamic processes and their additional unit consumption of fuel, such as from the fuel exergy to heat exergy in gas at theoretical combustion temperature, then to heat exergy in gas at actually exothermic temperature, and finally to heat exergy in heat products. The model has been applied to the unit consumption analysis for an ultra supercritical boiler on the basis of thermal calculation. Results show that among all the heat exchangers, the heat exergy obtained by working medium from boiler economizer is the least, and its exergy efficiency is accordingly the lowest, which proves boiler economizer to be most uneconomic, indicating that the boiler economizer actually restricts the improvement of generating efficiency of fossil fuel-fired power units.

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