Power Equipment

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  • 2019 Volume 33 Issue 6
    Published: 15 November 2019
      
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  • CFD Simulation Study of a Multi-line Flue Gas Velocity Measurement Method
    Qian Conghao, Feng Xuan, Zhu Xiaoliang
    2019, 33(6): 375-380.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To analyze the flue gas flow field in a horizontal flue duct under different conditions, a method was proposed for arrangement of sampling points in the flue duct to measure the gas velocity, while a model of chimney-flue flow field was established for coal-fired power plants, with which, CFD simulations were conducted. Results show that it is available to use the proposed multi-line method to measure the flue gas velocity, since there are straight line areas, where the flue gas velocity can represent the actual velocity of flue gas in the duct.
  • Stress Analysis and Fatigue Life Prediction for Constant Spring Hangers of Main Steam Piping
    Wei Hongming, Fan Peipei, Wei Jiang, Xue Kangkang, Song Zhanbing, Li Gen
    2019, 33(6): 381-385.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To study the effects of axial displacement and deflection angle on the stress of constant spring hangers, a model was established for the hangers of main steam piping using finite element method, and the fatigue life of these hangers was predicted in the areas with stress concentration. Results show that the stress concentration easily occurs in following areas or parts, such as the bolt at bottom of pipe clamp, the bolt for annular handle, the hanger rod and the contact area between main steam piping and piping clamp, etc. The fatigue life of the bolt for annular handle is greatly influenced by the axial displacement, while that of the material in the contact area between steam piping and piping clamp is greatly influenced by the deflection angle.
  • Retrofit Analysis of a Cogeneration Turbine Based on Exergy Analysis
    Shao Feng, Tan Rui, Cai Pei
    2019, 33(6): 386-388.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the theory of exergy analysis, a calculation model of exergy loss was derived and then used in economic analysis for retrofit of a cogeneration turbine. Results show that the method of exergy analysis makes up for the deficiency of the first law method of thermodynamics, which can accurately determine the volume, distribution and influence factors of exergy loss for relevant systems and facilities, pointing out the possibility of improvement for thermal processes or cycles.
  • Formula Derivation and Verification for Thermal Performance Index of Steam Turbines
    Lü Haizhen, Ding Lixin
    2019, 33(6): 389-392,398.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To determine the thermal performance index of steam turbines, formulas were derived for following thermal performance indexes, such as the ideal ratio internal power, ideal cycle efficiency, ideal cycle average heat absorption temperature, ideal cycle average heat release temperature and internal efficiency of steam turbines, etc. Taking the 660 MW steam turbine unit as an object of study, the thermal performance indexes of three principled thermal systems were calculated to prove the correctness of above formulas through data consistency verification. Three sets of data of design results were interpreted and discussed. Results show that the formulas derived could be used for calculation of actual complex reheat and regenerative cycles.
  • Study on Transient State Characteristics of a Deaerator for 1000 MW Units
    Chen Bingbing
    2019, 33(6): 393-398.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To prevent the feed pump cavitation during load rejection of a unit under sliding operation of its deaerator, an optimized design was conducted on the low-pressure feed water deaerating system and the deaerator arrangement, while the transient state characteristics of the deaerator was studied in detail. Based on theoretical analysis of the transient calculation model for the deaerator of a 1 000 MW ultra supercritical unit, the effects of following factors on the feed pump cavitation were analyzed, such as the selection of the deaerator operating condition for transient calculation, the tank volume of the deaerator, the diameter and length of the low-pressure feed water pipe, etc., which may serve as a reference for safe operation of the feed pump, optimal arrangement of the deaerator and energy saving of the power plant.
  • Study on Simultaneous Denitrification and Mercury Oxidation by Low-temperature Catalytic PPS Filter Materials
    Wu Linhu, Liu Meng, Li Yinsheng
    2019, 33(6): 399-403.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The polyphenylene sulfide (PPS) filter material was firstly modified by sodium dodecyl sulfate (SDS) to activate the surface of the PPS, which was then treated using impregnation-low temperature calcination (IC) method, coating (CO) method and in-situ (IS) method for simultaneous denitrification and mercury oxidation, while the influences of load capacity and reaction temperature on the simultaneous NO reduction and Hg0 oxidation of the catalysts were investigated in a fixed bed system. Results show that IS-N/PPS exhibits a superior denitrification and mercury oxidation performance under φ(O2)=5%, w(NO)=500×10-6, w(NH3)=500×10-6, and filtration rate=1.0 m/min. Both the NO and Hg0 conversion by catalytic PPS material increase first and then decrease with the rise of load capacity and reaction temperature, and the denitrification and mercury oxidation efficiency by IS-N/PPS could achieve their highest values at the same time, i.e. 89% and 94.5%, respectively, at the mole ratio of active component of 0.9 and the reaction temperature of 170℃.
  • Research on Operation Mode of a Slurry Circulating Pump for Energy Conservation of the 600 MW Unit
    Yu Guo, Liu Xiangmin, Shen Mingke
    2019, 33(6): 404-408,414.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To reduce the power consumption of slurry circulating pumps in the desulfurization system of a 600 MW thermal power unit after ultra-low emission retrofit for improvement of the unit economy, the operation mode of above pumps was optimized according to actually required slurry volume based on analysis of the operation data. Results show that compared with conventional operation ways, the energy saving mode helps to reduce the annual power consumption by 3.465 million kW·h, saving 1.559 3 million RMB of power cost each year.
  • Characteristic Loci Design for CCS of Thermal Power Units Based on Step-decreasing Beetle Antennae Search Algorithm
    Liu Qian, Yang Xiangdong, Lü Jianhong, Ge Hao
    2019, 33(6): 409-414.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    By combining the characteristic loci(CL)method with the step-decreasing beetle antennae search (SDBAS) algorithm, a coordinated control system (CCS) was design for subcritical thermal power units, in which, the form and necessary parameters of the controller were determined by CL method to ensure the stability of the CCS, while optimal controller parameters were obtained by combining the SDBAS algorithm to improve the control performance. Simulation results and engineering applications prove the combined method to be able to meet relevant engineering requirements.
  • Analysis on the Coordinated Control System of a 350 MW Supercritical CFB Boiler Unit
    Duan Bao, Fan Long, Hui Shien
    2019, 33(6): 415-421.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To overcome the control difficulties caused by slow combustion response and high thermal inertial of the coordinated control system in a 350 MW supercritical circulating fluidized bed (CFB) boiler unit, the main control feedforward amount of boiler was reasonably set up, the coal and water flow were precisely coupled and the responsiveness of steam turbine regulating valve was adequately excavated, thus to successfully achieve the purpose of coordinated load variation at 4.5 MW/min. Meanwhile, following suggestions were proposed for the control system, such as to determine the reference coal flow based on coal quality correction, determine the reference water flow based on coal-enthalpy loop analysis, propose the key coupling points for the main control circuit, and to perform logical optimization to handle the overtemperature and overpressure problems occurring in the supercritical CFB boiler unit, which may serve as a reference for the coordinated control system of similar units.
  • Design and Tracking Effect Analysis of a Mobile Traceable Photovoltaic Power System
    Zhang Xixin, Yang Fan, Liu Deli, Yin Qian, Song Pengfei, Tian Wentao
    2019, 33(6): 422-426.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A portable open-closed-loop low-cost dual-axis solar tracking system was designed for real-time monitoring on the operation conditions of relevant photovoltaic facilities, which was subsequently simulated and analyzed to study the performance of the system under different operation modes. Results show that the photovoltaic power generation could be significantly improved by 18%~27% in dual-axis tracking mode at different latitudes, and the error of the tracking system designed is within an acceptable range.
  • Research and Application of the Deep Peak Regulation Technology in a 300 MW Unit
    Tao Li, Yang Yu, Chen Guowei, Cheng Yingguan, Song Wenlei, Guo Fucai, He Xiang
    2019, 33(6): 427-431.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To optimize the operation parameters and control logics of a 300 MW subcritical boiler, operation tests were performed under 30% boiler rated load (BRL) condition after the following measures were taken, such as reducing the in-furnace gas temperature to avoid overheating of the reheat steam at high loads, improving the reheat steam temperature by enhancing the combustion in the furnace at low loads, balancing the flow of primary air and adjusting the baffle opening of secondary air, modifying the control logics for partial thermal configuration on combustion side and optimizing the protection parameters, etc. Results show that, with 2 coal mills in operation, the boiler can operate safely and steadily under 30% BRL condition, when better economic and environmental indicators could be obtained simultaneously.
  • Effectiveness Analysis on Upgrading of a GE 9F.03 Gas Turbine Using Advanced Gas Path
    Cheng Xun, Huang Weidong
    2019, 33(6): 432-437.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the retrofit on rotary and stationary blades of a 9F.03 gas turbine for cost reduction and efficiency improvement, during which, following measures were taken, such as upgrading the original hot path components into advanced kinds, adopting new materials able to withstand higher gas temperatures, and using better cooling, sealing and clearance control system, etc., so as to improve the gas turbine efficiency and output, and to promote the energy utilization. After the retrofit, the overall efficiency of the gas turbine has been significantly improved, the component life and maintenance interval have been extended, while the maintenance cost has been further reduced.
  • Study on Structure Retrofit for High-temperature Heating Surfaces of Utility Boilers
    Tian Tian, Yang Jing, Cheng Jianhua, Wang Pu
    2019, 33(6): 438-441.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To eliminate the potential overheating dangers caused by excessive heating of superheater tubes and no room for adjustment of reheater baffle due to variation of coal quality in a utility boiler, a retrofit scheme was proposed by optimizing the structure of relevant heating surfaces and reducing the surface of the low-temperature reheater considering the factor of future coal quality changes. Retrofit results show that the mass flow rate of superheater desuperheating water could be reduced by 30~40 t/h, while the opening of reheater baffle could be kept at 30%~45%, indicating that the adjustment margin has been recovered in a certain degree for the superheater desuperheating water regulating valve and the reheater flue gas baffle, showing expected effectiveness.
  • Study on the Technology for Improvement of Primary Air Temperature during Lignite Co-firing
    Chen Chaosong, Xiong Xianwei, Li Jianning
    2019, 33(6): 442-445.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To further increase the proportion of lignite co-firing in a power plant boiler and to reduce the cost of power generation, the temperature of primary air has been increased by adding steam heaters and guide plates in the primary air duct, where the steam extracted from the third stage of steam turbine is taken as the heating source. Application results show that the temperature of primary air could be increased by more than 30 K, resulting in increased proportion of lignite co-firing by 19% for the boiler.
  • Application of Flue Gas Waste Heat Recovery Technology in a 1 000 MW Coal-fired Boiler
    Wang Limin, Zhao Xianli, Li Yanwei
    2019, 33(6): 446-449.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To meet the design requirements of energy saving, emission reduction, high efficiency and wide load reduction of power supply coal consumption for 2×1 000 MW units, from the point of view of improving the thermal energy grade of the waste heat in boiler flue gas, and under the premise ensuring a safe operation of the boiler air pre-heater, a method was proposed by combining the low-temperature condensate water with the low-temperature economizer to improve the thermal energy grade. Operation practice shows obvious energy saving effectiveness.