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    Research & Analysis
  • Research & Analysis
    Analysis and Application on Energy Efficiency of Gas and Steam Combined Cycle Unit
    Zhu Yadi, Cai Can, Hao Jiangang, Xie Daxing, Xu Tingting
    2022, 36(5): 297-303. https://doi.org/10.19806/j.cnki.fdsb.2022.05.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking a typical domestic gas and steam combined cycle unit as the research object, a five-level system for energy efficiency indicators was established. Based on the simulation calculation model by Thermoflow software, analyses were conducted on the characteristics of the unit under different conditions, and the reference values and heat consumption deviation factors of main energy efficiency indicators within full load conditions were calculated. After which, the effects of indicators on the unit economy were compared and analyzed. Calculation results show that the unit economy is significantly influenced by the main steam pressure, the turbine back pressure, and the compressor efficiency.
  • Research & Analysis
    Influence of Hot Flue Gas Evaporation from Desulfurization Wastewater Bypass on Flue Gas Composition
    Cai Chenjian, Liu Fengjun, Chen Heng, Zhan Lingxiao, Gu Liyan, Yang Linjun
    2022, 36(5): 304-309. https://doi.org/10.19806/j.cnki.fdsb.2022.05.002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the experimental platform of desulfurization wastewater evaporation by bypass hot flue gas via rotary spray, the influence of process engineering on composition of the flue gas was investigated. The mass balance model was established for the dry device in 330 MW unit, and the dust concentration, HCl concentration, SO2 concentration and moisture content before and after dry tower were calculated. The contrastive analysis has also been performed based on the calculation and test results, to further verify the rationality of mass balance model.
  • Research & Analysis
    Optimization of Heating Unit Based on Advanced Exergy Analysis Method
    Wang Wenhuan, Li Qiubai, Wang Jiongming, Tan Rui, Huang Qilong, Dai Xiaoye, Shi Lin
    2022, 36(5): 310-315. https://doi.org/10.19806/j.cnki.fdsb.2022.05.003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Analyses were conducted on a 300 MW heating unit through the traditional exergy analysis method and the advanced exergy analysis method, respectively, and following parameters of each component were calculated, such as exergy loss, exergy efficiency, exergy loss ratio, internal source exergy loss, external source exergy loss, avoidable exergy loss, etc. The avoidable internal source exergy loss rates of all components were compared, while the distribution of exergy loss within the component was researched. Results show that, by adopting the advanced exergy analysis method, the components of the heating unit for improvement are in order as follows:steam turbine, low-pressure heater, boiler, condenser. With the advanced exergy analysis method, it is helpful to design the improvement scheme based on the specific component, and reduce the exergy loss of the system.
  • Research & Analysis
    Control System Simulation and Valve Flow Analysis of Laval Type Gaseous Fuel Regulating Valve
    Liu Tingting, Zhang Yicen, Yu Haibin, Dai Yiping
    2022, 36(5): 316-321. https://doi.org/10.19806/j.cnki.fdsb.2022.05.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The composition and principle of the control system of gas turbine fuel valve set were introduced, the control system model with good dynamic response below 1 Hz was established, and the hydraulic control system of the fuel valve set was simulated, then the flow characteristics of Laval type regulating valve was analyzed by FLUENT software, in order to lay the theoretical foundation for the design of hydraulic servo valve control Laval type valve.
  • Research & Analysis
    Characteristic Analysis and Fault Simulation of WFGD System in Thermal Power Plant
    Zhang Jinhang, Qiao Zongliang, Si Fengqi, Ma Huan, Wang Yong, Chen Rongze
    2022, 36(5): 322-327. https://doi.org/10.19806/j.cnki.fdsb.2022.05.005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To study the fault characteristics of the wet flue gas desulfurization (WFGD) system, taking the desulfurization tower in a thermal power plant as a research object, two models were established for the flow, heat transfer and component diffusion of the flue gas, and the movement, mass transfer and chemical reaction of the slurry liquid drop, respectively. Meanwhile, the above two models were coupled through user-defined function (UDF). Analyses and simulations were conducted on the faults of the local blockage of the spray pipe and the lower pH condition of the liquid drop in the desulfurization tower. Results show that, when the first layer of the spray pipe is partially blocked, the SO2 mass fraction in the blocked area has a slight increase compared with the normal condition. The higher the height is, the weaker the influence of the local blockage on the increase of the SO2 mass fraction would gradually be. When the pH of the liquid drop decreases from 5.5 to 4.5, the decreasing rate of the desulfurization efficiency gradually increases with the decrease of the pH of the liquid drop.
  • Research & Analysis
    Analysis of Wet Steam Two-phase Flow in Cyclone Separator
    Zhang Meifeng, Chang Chongxi, Na Hongwei, Ma Xiqiang, Yan Lingbo
    2022, 36(5): 328-332. https://doi.org/10.19806/j.cnki.fdsb.2022.05.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In the separation principle of the cyclone separator, the discrete phase numerical model was established. The droplets track in the separator was simulated by FLUENT software, and the separation efficiency was also compared. The results show that the small size droplets has excellent tracing ability, will be discharged from the exhaust port, and has low separation efficiency. The critical size droplets will be dumped to the wall and separated in the centrifugal force. Due to the complexity of the flow, the secondary flow is easy to occur. The separation efficiency will be improved by reasonably designing the cyclone separator structure.
    • New Energy
  • New Energy
    Multi-objective Optimization of Photo-thermal and Photovoltaic Utilization Coupling CCHP Based on NSGA-Ⅱ
    Zhao Dandan, Jiang Daijun, Xu Jinzhao, Wang Dengwen, Wang Jun
    2022, 36(5): 333-338. https://doi.org/10.19806/j.cnki.fdsb.2022.05.007
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A system was proposed with the photo-thermal and photovoltaic utilization coupling combined cooling, heating and power system (CCHP), and the coupling system was optimized through taking following three factors as the optimization objectives based on fast and elitist multi-objective genetic algorithm (NSGA-Ⅱ), such as the annual cost saving rate, the primary energy saving rate, and the carbon dioxide reduction rate. Simulation results show that, when the primary energy saving rate of the coupling system is increased from 8.84% to 35.81%, the annual cost saving rate is decreased from 15.31% to -59.77%. By selecting the scheme with the multi-objective optimization, the system can achieve economic benefits while ensuring the energy advantages.
    • Environmental Technology
  • Environmental Technology
    Distribution and Migration Characteristics of Ca2+, Mg2+ and Si4+ in Desulfurization System of Thermal Power Plant
    Sun Lijuan, Yang Maolin, Du Yinggang, Xue Nianjie, Qin Zhi
    2022, 36(5): 339-344. https://doi.org/10.19806/j.cnki.fdsb.2022.05.008
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to maintain the long-term and stable operation of the desulfurization system, it is necessary to monitor fresh slurry, primary absorption tower slurry and secondary absorption tower slurry to study distribution and migration characteristics of Ca2+, Mg2+ and Si4+. Results show that after the reaction of SO2 and limestone slurry, Ca2+ and Mg2+ in limestone migrated to gypsum solid and MgSO4 solution, respectively, while Si4+ did not migrate. The desulfurization wastewater was used to prepare limestone slurry, compared with fresh slurry, the Mg2+ in the primary and secondary absorption tower slurry were enriched by 10.68 and 3.59 times, respectively. The moisture content and CaSO3·1/2H2O content of gypsum were mainly affected by the operating conditions of the equipment, while the CaSO4·2H2O and CaCO3 content of gypsum were directly affected by the quality of the absorption tower slurry. Controlling the quality of fresh slurry strictly can optimize the operation of desulfurization system from the source. To build new waste water concentration device is an effective way to improve the quality of the absorption tower slurry.
    • Nuclear Technology
  • Nuclear Technology
    Research on Steam Turbine Selection of Secondary Recirculating Nuclear Power Unit Based on Cold-end Optimization
    Zhou Guangsha, Jin Tao, Qu Xiaoming
    2022, 36(5): 345-349. https://doi.org/10.19806/j.cnki.fdsb.2022.05.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the selection of steam turbines in nuclear power units with the secondary recirculating cooling system, based on the optimal vacuum theory and the minimum annual total cost method, combined with the characteristics of the secondary recirculating cooling system, the influencing factors of the steam turbine selection were analyzed, and the schemes were proposed and compared. Results show that, with considering the cold-end optimization, the actual operation of the steam turbine can be more reasonably matched for the selected steam turbine type. This may serve as a reference for the selection of steam turbines in similar nuclear power units.
    • Design & Manufacture
  • Design & Manufacture
    Discussion on Design Optimization of Thermal Performance of Steam Turbines in Ultra Supercritical Units
    Shen Chun, Shao Gangbei
    2022, 36(5): 350-354. https://doi.org/10.19806/j.cnki.fdsb.2022.05.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the third generation flow passage technology, a new generation flow passage technology for the ultra supercritical units was researched. After which, combined with the double reheat technology, corresponding parameters were selected for the research and analysis. Results show that, the thermal performance of the unit would be improved by adopting the new generation flow passage technology and the double reheat technology, and the steam turbine efficiency can be increased by 0.51.0 percentage points.
  • Design & Manufacture
    Manufacturing Process Analysis of Circumferential Seam Between Water Chamber Head and Tube Bundle Assembly of Steam Generators
    Long Huisong
    2022, 36(5): 355-357. https://doi.org/10.19806/j.cnki.fdsb.2022.05.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The manufacturing of circumferential seam between water chamber head and tube bundle assembly of steam generators includes important processes such as assembly, welding, heat treatment and nondestructive testing. Their design and manufacturing process requirements are complex and the implementation of production organization is difficult. The processes in circumferential seam manufacturing are introduced in detail, and the key points of work control are summarized to provide reference for equipment manufacturing in subsequent projects.
    • Operation & Retrofit
  • Operation & Retrofit
    Structural Resonance Analysis and Treatment of Variable-frequency Condensate Pump
    Xu Hui, Wen Xingyuan, Xia Yalei, Wu Yajun, Ji Dongmei
    2022, 36(5): 358-362. https://doi.org/10.19806/j.cnki.fdsb.2022.05.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In view of the structural resonance failure of a 2B variable-frequency condensate pump, the causes of such failures have been analyzed from the perspective of electro-mechanical coupling. It has been pointed that the harmonics of the lower integer order generated by the frequency converter make the drive motor produce a pulsating torque close to the natural frequency of the shaft system and the casing, thus triggering the resonance of the condensate pump structure. The site adopts a fine dynamic balancing scheme to decrease the vibration amplitude from 445 μm to 41 μm, and finally effectively solves the vibration fault.
  • Operation & Retrofit
    Retrofit on the Booster Pump Shell of Steam Turbine-driven Feedwater Pump in a Domestic 600 MW Unit
    He Yongtao, Wang Zhaoli
    2022, 36(5): 363-366. https://doi.org/10.19806/j.cnki.fdsb.2022.05.013
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem that the leakage occurred frequently in the middle plane of the booster pump of the steam turbine-driven feedwater pump in a power plant during operation, analyses and discussions were conducted on the structure and material of the booster pump, and corresponding measures were carried out for the booster pump. Results show that after retrofitting, the booster pump can operate in a good condition and without leakage, while the performance of the booster pump is improved. This may serve as a reference for power plants with similar booster pumps.
  • Operation & Retrofit
    Cause Analysis and Treatment on Operation Damage of Seal Line Between Disc and Seat for a Horizontal Main Steam Valve
    Wei Yingqiang, Yan Yi
    2022, 36(5): 367-370. https://doi.org/10.19806/j.cnki.fdsb.2022.05.014
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The seal line between valve disc and valve seat for the horizontal main steam of a steam turbine unit was damaged during operation. According to the characteristics of damage, the causes of the damage were analyzed. Combined with the structural characteristics of different types of main steam valves, the treatment measures to solve the problem were put forward.