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    Research & Analysis
  • Research & Analysis
    Research and Application of Upgrading Technology for Ansaldo AE94.3A EVO2+ Gas Turbine
    Wu Wei
    2024, 38(3): 133-137. https://doi.org/10.19806/j.cnki.fdsb.2024.03.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The main technical optimization principles of the Ansaldo AE94.3A EVO2+ gas turbine-generator set was introduced. A comparative technical analysis was conducted to explain the energy-saving and economic benefits of the unit, while the localization application of the AE94.3A EVO2+ gas turbine-generator set and accessories was discussed. Results show that, the energy saving, emission reduction, and economic benefits improvement of the AE94.3A EVO2+ gas turbine-generator set are remarkable. Due to some of the gas turbine components are domestically designed and manufactured, and the maintenance of the gas turbine has also achieved full independence, the overall cost of the entire units over the whole life cycle is significantly reduced.
  • Research & Analysis
    Influence of Rear Heating Surface Tarnishing on Flue Resistance of Waste Heat Boiler in a Gas-Steam Combined Cycle Unit
    Zhang Wei, Yu Zhefeng, Shi Zifu, Tao Zhentao, Li Hongmei, Huang Yue, Yan Fengping, Zhou Yonggang
    2024, 38(3): 138-143,156. https://doi.org/10.19806/j.cnki.fdsb.2024.03.002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For a gas-steam combined cycle unit with long-term shutdown and standby, the flow resistance of flue gas was increased by the tarnishing of rear heating surface finned tube with outer helical fins in the waste heat boiler, which further leaded to the abnormal start-up of the gas turbine. Researches were conducted on the influence of the surface tarnishing status of finned tube on the flow resistance characteristics through on-site data monitoring, numerical simulation, and experiment in a small test bench. Results show that, the flow resistances of No.5 and No.6 models in the waste heat boiler rear flue increase significantly. The main reason of the increase of flow resistance is not the rust accumulation in leeward side of the finned tube, but the increase of rust thickness in both sides. After the rust removal, the flow resistance characteristics can be improved with the thinner fins and the enlarged cross-sectional area, and which are better than those of new finned tubes.
  • Research & Analysis
    Performance Analysis of Typical F-class Gas-Steam Combined Cycle Units Under Variable Inlet Gas Heating Conditions
    Xia Xuemao
    2024, 38(3): 144-149,156. https://doi.org/10.19806/j.cnki.fdsb.2024.03.003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking two typical F-class gas-steam combined cycle units of GE 9FA and Mitsubishi M701F as the research objects, a thermal model of gas-steam combined cycle with inlet gas heating design was established, and a simulation calculation for the thermal performance of unit was carried out. A univariate analysis was conducted on the effects of the environmental temperature, heating temperature rise, and unit load on the unit performance, while a comparative analysis was conducted on the improvement of inlet gas heating efficiencies of two types of units under different unit loads. After which, the optimal intake parameters under different unit loads were given. Results show that, under the same inlet gas heating condition, the efficiency improvement of 9FA unit is higher than that of M701F unit, and the unit combined cycle efficiency increases with the increase of heating temperature rise. Under the same heating temperature rise condition, the optimal environmental temperature for inlet gas of 9FA unit is higher than that of M701F unit. Research results have important reference significance for the application of inlet gas heating technology in F-class gas-steam combined cycle units.
  • Research & Analysis
    Collaborative Optimization of Velocity Field and Concentration Field of Coal-fired Unit Denitrification System
    Wang Jingang, Zeng Liangliang, Yang Xiaoming, Li Jianning
    2024, 38(3): 150-156. https://doi.org/10.19806/j.cnki.fdsb.2024.03.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    There were problems such as reduced unit efficiency, blocked air preheater and excessive ammonia escape during deep peak regulation in the ultra-clean emission process of a 300 MW thermal power generating unit. The cold and hot state mapping test was carried to evaluate and diagnose the inlet flow field and the NOx concentration in outlet section of the selective catalytic reduction (SCR) denitrification system, and the application scheme for the efficient operation of the system was proposed. Computational fluid dynamics (CFD) software was used for numerical simulation, and the solution was demonstrated by cold state physical model. The results of engineering practice application show that, the collaborative optimization can achieve a good flue gas flow distribution and maintain a low pressure drop in the denitrification system. The velocity relative standard deviation of the catalyst inlet in the first layer is reduced to 10.79%, the total pressure drop of the denitrification system is less than 600 Pa, and the net coal consumption is reduced by 0.3 g/(kW·h), which has better energy saving and emission reduction benefits.
  • Research & Analysis
    Analysis on the Influence of the Gap Between Grid Plate and Component of Air Preheater on Exhaust Gas Temperature in a 330 MW Boiler
    Liu Chaocheng, Huang Xuefei
    2024, 38(3): 157-160. https://doi.org/10.19806/j.cnki.fdsb.2024.03.005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to analyze the influence of the gap between the rotary air preheater grid plate and the heat exchange component on the exhaust gas temperature, for a 330 MW power station boiler rotary air preheater, two models of equal resistance and equal flow velocity were established to calculate the exhaust gas temperature with different gaps between the grid plate and the component, while the exhaust gas temperatures of the air preheater with different gap values were obtained. Results showed that, when the gap value is less than 6 mm, the influence on exhaust gas temperature is slight, and when the gap is more than 12 mm, the influence on exhaust gas temperature is greater. Through a comparison between calculation results and actual operation parameters, the maximum relative deviation of exhaust gas temperature is 2.73%, which verifies the accuracy of the proposed calculation methods.
  • Research & Analysis
    Analysis and Solution of Shaft Gland Steam Supply Failure of HTR-PM Steam Turbine
    Ye Lin, Yao Yao, Ma Xiqiang, Huang Peng, Wang Lei, Zhao Jingkai, Cui Peng
    2024, 38(3): 161-164,171. https://doi.org/10.19806/j.cnki.fdsb.2024.03.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The steam turbine shaft gland system of high temperature gas cooled reactor demonstration project (HTR-PM) was introduced. The causes of shaft gland steam supply failure were analyzed, and three solutions were put forward: residual steam of steam generator and pipe supply shaft gland, auxiliary electric boiler to shaft gland steam supply pipe transformation, high temperature air supply shaft gland. The three solutions were compared, while their advantages and disadvantages in cost, reliability and operation limitation were analyzed. Results show that above three solutions are feasible. The research results provide a reference for solving the problem of shaft gland steam supply failure of HTR-PM steam turbine.
    • Material Technology
  • Material Technology
    Failure Cases Analysis of Non-critical Pressure Metal Components in Generator Sets
    Wu Dongzhan, Gu Shuchao, Wang Jiahe
    2024, 38(3): 165-171. https://doi.org/10.19806/j.cnki.fdsb.2024.03.007
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In addressing six failure cases involving non-critical pressure metal components in coal-fired generating units and gas-steam combined cycle units of power system, the failure cases were analyzed through a combination of macroscopic observation, material analysis, microstructure analysis, and mechanical property analysis with the service environment of the units. Results show that, the failure locations of components are often found at stress concentrations with abrupt sectional changes, and the main causes for failure are identified as external environmental corrosion and fatigue damage. Misuse of material or inadequate control of production process leads to poor microstructure quality and a decrease in overall macroscopic mechanical properties and accelerates component failure. As non-critical pressure components of the shaft, auxiliary bolts or other equipment in generator sets are not given adequate technical supervision and management attention, leading to significant issues such as the misuse of materials or inferior material quality.
  • Material Technology
    Failure Analysis on TP310HCbN Steel Tube of Boiler High Temperature Reheater with Long Term Service
    Song Yu, Liao Yonghao, Yu Xin, Nie Haijun, Yang Lin
    2024, 38(3): 172-176. https://doi.org/10.19806/j.cnki.fdsb.2024.03.008
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For a boiler high temperature reheater with long term service after 46 000 hours in a 660 MW ultra-supercritical unit, researches were conducted on the microstructure and mechanical properties of the leaked TP310HCbN steel tube by means of metallography test, scanning electron microscopy, tensile property test and impact property test. Results show that, the aging grade of the leaked TP310HCbN steel tube microstructure after long term service at high temperature is 3-4, and the tube material presents a serious embrittlement property with a large mount of carbide precipitating at the grain boundary, which result in the insufficient toughness of the tube material. A large number of micro-cracks are formed on the surface of outer tube by impacting, after which, the tube cracks gradually expand and eventually lead to leakage with the increase of service time.
  • Material Technology
    Analysis and Optimization on Cracking Failure of Header Fillet Weld in an Ultra-supercritical Boiler
    Dong Peng, Li Haiyang, Lai Weilong, Zhou Yanxing, Li Linhao, Li Jinwei, Yang Hao, Luo Guanrui
    2024, 38(3): 177-181,193. https://doi.org/10.19806/j.cnki.fdsb.2024.03.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of the cracking failure of the fillet weld at extended side wall outlet header in an ultra-supercritical boiler of a power plant, comprehensive analyses were conducted on the cracking failure reasons of the fillet weld from the aspects of material chemical composition, microstructure, hardness tests and service condition, while optimization measures were synthetically proposed based on welding process, heat treatment process and weld form. Results show that, the header material is 12Cr1MoVG, and the chemical composition, microstructure and hardness of the leaked header fillet weld all can meet the requirements of standards. The complex additive effects of welding residual stress and service stress result in the cracking failure. The service time can be prolonged by adopting the optimization measure of reducing the concentrated stress in fillet weld. This can provide an important reference for the daily supervision and quality control of similar boiler tubes in power plants.
    • Fault Diagnosis
  • Fault Diagnosis
    Fault Diagnosis of Rotor Winding In-ter-turn Short Circuit in Turbine Generator Based on MSET
    Huang Yangsen
    2024, 38(3): 182-188,193. https://doi.org/10.19806/j.cnki.fdsb.2024.03.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to solve the rotor winding in-ter-turn short circuit in a turbine generator, an online diagnosis method based on multivariate state estimation technique (MSET) was proposed. The state matrix was built by using sliding window and Euclidean distance. The exciting current and reactive power calculation models were constructed based on MSET. According to the average value of the relative deviation or residual value between the operating value and the calculated value of the generator, an online diagnosis method for rotor winding in-ter-turn short circuit fault was constructed, and the operation data of a steam turbine generator was used for verification. Results show that, the proposed online diagnosis method is feasible, which meets the requirements of rotor winding in-ter-turn short circuit fault diagnosis, and reduces the probability of fault misjudgment.
  • Fault Diagnosis
    Diagnosis of Tower Foundation Loosening Fault in WTGS Based on Simple Sound Localization Method
    Wang Zishun
    2024, 38(3): 189-193. https://doi.org/10.19806/j.cnki.fdsb.2024.03.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking a wind turbine generator set (WTGS) with abnormal noise as the research object, vibration pulse signals generated during operation were obtained through using a dual-channel vibration detection instrument, and analyses were conducted according to the sequence of signal transmission based on simple sound localization method. A comparison between the vibration frequency of abnormal noise and the oscillation frequency of tower was carried out, and the source of abnormal vibration was investigated by vibration tests. Through comprehensive analysis and test for vibration, it is finally confirmed that the exact vibration source with abnormal noise is at the tower bottom of WTGS. The fault has been found successfully with simple sound localization method, and this can provide a practical and feasible technical way for the design optimization and operation stability improvement of WTGS.
    • Operation & Retrofit
  • Operation & Retrofit
    Analysis and Treatment on the Large Amplitude Vibration of No.3 Bearing in a Turbine Generator
    Song Chengcai, Wang Changwei
    2024, 38(3): 194-198. https://doi.org/10.19806/j.cnki.fdsb.2024.03.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For the No.3 bearing with large amplitude vibration in a 25 MW turbine generator, the problem of abnormal vibration was not be solved after maintaining in several times, which resulted in the shutdown of the turbo-generator set. Through analyses on the operation parameter, vibration spectrum, bearing structure and maintenance process of the turbine generator, it is confirmed that the main reason of large amplitude vibration is the change of centering, which is caused by the friction between the sinking generator rotor and the shaft seal and oil shield with the loosening of support system due to the false connection of the supporting bracket at bearing bottom. By means of optimizing the centering adjustment process for rotor and adjusting the assembling clearance for bearing, the vibration amplitude of No.3 bearing is reduced significantly, which can guarantee the safety and stability of the unit operation. The reasonable maintaining and assembling method for rotor is vitally important for the reliable operation of turbine generator.