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  • Research & Analysis
    Design Optimization on the Heat Transfer System of a Simplified Supercritical CO2 Power Cycle
    Zheng Shuxing, Chen Yaping, Wu Jiafeng, Zhu Zilong, Fang Fang
    2020, 34(6): 371-378. https://doi.org/10.19806/j.cnki.fdsb.2020.06.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Optimization was conducted on the preliminary design of a heat exchanger system with simplified supercritical CO2 power cycle targeting high-efficiency power generation and CO2 capture. Taking the HX1-1 heat exchanger between the turbine exhaust gas and the circulating CO2 gas in the heat recovery system of a 100 MW power unit as an example, the effects of the shell inner diameter, tube outer diameter and inclination angle on the heat transfer coefficient and shell-side pressure drop were discussed. Moreover, the relationship between the turbine back pressure and cycle efficiency was given, which may serve as a reference for structural optimization of the heat exchanger system to improve the cycle efficiency and economy.
  • Research & Analysis
    Performance Investigation on a Parallel Kalina Cycle for Power and Refrigeration Cogeneration
    Fang Fang, Chen Yaping, Wu Jiafeng, Zhang Shaobo
    2020, 34(6): 379-385,391. https://doi.org/10.19806/j.cnki.fdsb.2020.06.002
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    The performance of a new parallel type Kalina cycle with adjustable power/cold ratio was simulated and analyzed in the period of ice making. The heat exchange surface in the first regenerator was increased to introduce the dilute solution from the second regenerator to participate in the heating of the basic solution. The effects of the following factors on the cycle performance were analyzed, such as the working medium concentration, split fraction, pinch temperature difference at boiler bubble point and the superheat degree. Results show that the cycle split fraction gradually increases with the rise of pinch temperature difference at boiler bubble point. When the pinch temperature difference is increased from 20 K to 60 K, the range of minimum split fraction of cycle can be extended from 0.5181.000 to 0.3831.000, while the maximum refrigeration output of cycle is increased from 315.4 kW to 489.7 kW, but the power recovery efficiency is somewhat reduced.
  • Research & Analysis
    Control Optimization of an Integrated Intelligent Energy System Based on Big Data Analysis
    Guo Rong, Zhang Qiang, Chen Jiaying, Chen Rongze
    2020, 34(6): 386-391. https://doi.org/10.19806/j.cnki.fdsb.2020.06.003
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    To obtain optimum operation of an integrated intelligent energy system, a relationship model was established for the cooling load, system energy consumption, controllable variables of system equipment and uncontrollable variables of the environment, based on which, the reliability of the model was calculated, while the optimal control strategy was solved with the minimum energy consumption of the system as the optimization object. Results show that the energy consumption has been obviously reduced after optimization of the system is taken, indicating that the energy saving effectiveness has been achieved.
  • Research & Analysis
    Comparative Analysis on Two Energy Saving Calculation Methods for the Low-temperature Flue Gas Waste Heat Utilization System of a 1 000 MW Unit
    Ding Yanfeng
    2020, 34(6): 392-395. https://doi.org/10.19806/j.cnki.fdsb.2020.06.004
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    For the low-temperature waste heat utilization system of a 1 000 MW unit, the energy-saving benefits were calculated using equivalent enthalpy drop method and Thermoflex software method, respectively, including an introduction to the specific calculation processes, and a comparative analysis on the advantages, disadvantages and available conditions of the two methods. It is recommended using the equivalent enthalpy drop method in the preliminary design of a project, and adopting the Thermoflex software method in the post evaluation of the project.
  • Research & Analysis
    Effects of BFPT Efficiency Improvement on Heat Rate of the Main Steam Turbine in a 600 MW Unit
    Duan Jiang, Li Ming
    2020, 34(6): 396-398. https://doi.org/10.19806/j.cnki.fdsb.2020.06.005
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    The energy level efficiency method was used to analyze the energy loss in the thermal system of a 600 MW subcritical steam turbine under turbine heat acceptance (THA) condition, during which, the energy efficiency and energy loss of each thermal system were obtained. The accuracy and ease of use of the energy level efficiency method were verified, while the influence of the efficiency improvement of the boiler feed pump turbine (BFPT) on the heat rate of the 600 MW subcritical steam turbine was further analyzed.
    • Material Technology
  • Material Technology
    Comparative Study of High-temperature Fracture Toughness for Nozzle-Safe End Welding Joints
    Yang Chengdong, Liu Meng, Zhang Maolong, Ru Xiangkun, Tang Weibao
    2020, 34(6): 399-403. https://doi.org/10.19806/j.cnki.fdsb.2020.06.006
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    A comparative study was conducted on the high-temperature (330 ℃) fracture toughness of two different types of nozzle-safe end welding joints between SA508 and 316L with and without nickel-based alloy buttering. Results show that the high-temperature J-R resistance curve and fracture toughness of weld metal lie between SA508 and 316L. The high-temperature J-R resistance curve and fracture toughness of interface cracks are the lowest, and the resistance to ductile fracture initiation and propagation is the lowest at the interface. The high-temperature J-R resistance curve and fracture toughness of the metal in fusion zone, heat affected zone and weld centre area of nozzle-safe end welding joints with nickel-based alloy buttering are slightly higher than that without buttering. The high-temperature J-R resistance curve and fracture toughness of the joint without buttering can reach the levels with nickel-based alloy buttering.
    • Environmental Technology
  • Environmental Technology
    Experimental Study on Coal-Biomass Co-combustion of a CFB Boiler
    Chen Tuo, Li Debo, Zeng Tinghua, Zhou Jielian, Feng Yongxin, Liao Hongkai, Zhang Weitian
    2020, 34(6): 404-408. https://doi.org/10.19806/j.cnki.fdsb.2020.06.007
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    Taking the 50 MW circulating fluidized bed (CFB) boiler that burns coal and biomass mixtures as an object of study, the effects of biomass blending ratio on the following parameters were investigated, such as the boiler efficiency, the NOx emission concentration and the SO2 emission concentration, etc. Results show that at the unit load of 60 MW, the boiler efficiency would be 79.27%, 77.43%, 81.49% and 84.02% accordingly, when the mass fraction of biomass is 0%, 15%, 30% and 45%, respectively; at the unit load of 50 MW, the boiler efficiency would be 79.80%, 81.59%, 82.82% and 84.33% accordingly, when the mass fraction of biomass is 0%, 15%, 30% and 45%, respectively. The application of coal-biomass co-combustion technology helps to reduce the NOx generation and desulfurizing agent consumption, when the dust emission could simultaneously meet the requirement of environmental protection.
  • Environmental Technology
    Study on Ultra-low Emission Retrofit of a 9E Gas Turbine with DLN 1.0 Combustion System
    Hong Yaguang
    2020, 34(6): 409-412,430. https://doi.org/10.19806/j.cnki.fdsb.2020.06.008
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    To reduce the NOx emission of a 9E gas turbine with DLN 1.0 combustion system, a study was conducted on the two main retrofit schemes, i.e. the DLN 1.0+ scheme and the selective catalytic reduction (SCR) denitration system scheme, to which, the key technologies were explained while a comparative analysis was performed. Results show that both the schemes could satisfy the standard requirement of NOx emission. The scheme of DLN 1.0+ keeps consistency with the original system in technology, but both the initial investment cost and the late maintenance cost are high, which limit the localization of the gas turbine technology. For the scheme of adding a new SCR denitration system, the equipment of SCR denitration system would cause a series of issues in equipment running and management, but it has low requirement in technology and low cost of investment.
    • New Energy
  • New Energy
    Research on Integrated Operation of Pumped Storage Power Station and Coal Power Unit
    Chen Weizhong
    2020, 34(6): 413-416. https://doi.org/10.19806/j.cnki.fdsb.2020.06.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the features of a pumped storage power station. Based on economic analysis, an integrated operation scheme was proposed, which takes the coal power unit and pumped storage power station as the same dispatching objective. Results show that the scheme can help to improve the efficiency and economy of energy utilization, which is in line with the direction of digital power grid development.
    • Operation & Retrofit
  • Operation & Retrofit
    Theoretical Analysis and Experimental Verification on the New NCB Heating Technology of a 135 MW Unit
    Liu Shuai, Xia Ming, Zheng Lijun, Yu Cong, Liu Guobi, Wang Xiaolong, Zeng Jun, Wang Long
    2020, 34(6): 417-421. https://doi.org/10.19806/j.cnki.fdsb.2020.06.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the operation flexibility and heating capacity of thermoelectric units, a 135 MW unit was retrofitted by new extraction condensing back-pressure (NCB) heating technology, during which, the potential hazards were theoretically analyzed, such as the windage overheating, the water erosion of blades and the flutter fracture after cutting the steam input of low-pressure cylinder, etc., and subsequently corresponding countermeasures were proposed. Retrofit results prove the new NCB heating technology to be applicable to domestic thermoelectric units.
  • Operation & Retrofit
    Failure Analysis of the Air Preheater Regenerative Plate in a 600 MW Unit
    Chen Xiaoqiang, Gong Kun, Peng Yuexi, Zhang Lin, Lei Jiankang, Zhao Lingling
    2020, 34(6): 422-426. https://doi.org/10.19806/j.cnki.fdsb.2020.06.011
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    To solve the problems of serious ash blocking and corrosion existing in the air preheater of a 600 MW unit, an analysis was conducted on the causes leading to the failure of the air preheater regenerative plate, while experimental tests were carried out. Results show that the material quality of the regenerative plate at hot end of the air preheater is good, where the wear and corrosion are serious; the material quality of the regenerative plate in middle section and at cold end is poor, where serious accumulation and corrosion of ammonium bisulfate ash exist.
  • Operation & Retrofit
    Failure Analysis of Water Wall Tubes in a 600 MW Supercritical Unit
    Wu Yue
    2020, 34(6): 427-430. https://doi.org/10.19806/j.cnki.fdsb.2020.06.012
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    The macroscopic examination, metallographic examination and hardness test were performed to analyze the leakage reasons of water wall tubes in a 600 MW supercritical unit. Results show that the failure was found to be caused by the penetrating cracks generated at the fusion line of the weld during long-term services under the combined action of welding residual stress and thermal stress due to too large welding heat input and structural stress existing at the corner of side wall.
  • Operation & Retrofit
    Research on the Bearing Bush Oil Leakage Failure in a 330 MW Turbo-Generator Set
    Bai Hongsen
    2020, 34(6): 431-433,438. https://doi.org/10.19806/j.cnki.fdsb.2020.06.013
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of severe oil leakage existing in the bearing bush of a turbo-generator set, an analysis was conducted, and subsequently the problem was found to be caused by that the negative pressure of the main engine lubricating oil system cannot be established normally, after which, the following countermeasures were proposed and taken, such as plugging the leakage point in the lubricating oil system, replacing the inlet filter element and outlet valve of the exhaust fan, and adjusting the gap of the bearing bush, so as to establish normal negative pressure for the main engine lubricating oil system.
  • Operation & Retrofit
    Heating Retrofit of 330 MW Coal-fired Units by Adding a Back-pressure Turbo-Generator Set
    Xu Xiao, Tang Lei, Zhou Chuanwen, Yang Rui
    2020, 34(6): 434-438. https://doi.org/10.19806/j.cnki.fdsb.2020.06.014
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For the power plant originally taking its high-temperature reheat steam as the outgoing heating source, a retrofit was carried out on the heating system of its two 330 MW subcritical coal-fired units by adding a back-pressure turbo-generator set, after which, an analysis was conducted. Results show that the technology helps to realize the step utilization of steam energy and reduce the power consumption of the units, thus improving the economic benefits of the power plant. This may serve as a reference for the retrofit of similar heating units.
  • Operation & Retrofit
    Analysis and Disposal on Field Balancing of Large Steam Turbine Units
    Chen Jincheng
    2020, 34(6): 439-441. https://doi.org/10.19806/j.cnki.fdsb.2020.06.015
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The mechanism of vibration caused by unbalanced mass was theoretically analyzed. Combined with an unbalanced mass case of a 600 MW turbo-generator rotor, an approximate calculation method was proposed and applied. Results show that compared with traditional vector equilibrium way, this method requires only once unit shutdown to add balancing weight to improve the dynamic balance of the rotor, effectively reducing the frequency of unit shutdowns.
  • Operation & Retrofit
    Application Analysis of Three Types of Steam-driven ID Fan Technologies
    Xue Hai, Yang Wenzheng
    2020, 34(6): 442-445. https://doi.org/10.19806/j.cnki.fdsb.2020.06.016
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For three main types of domestic steam-driven ID fan technologies, analysis and comparison were conducted on the equipment layout, technical features and the economy, while problems existing in upgrading and operation of the steam-driven ID fans were summarized. Results show that the back-pressure steam-electric dual driven scheme is the simplest in system configuration, requires less area of site, has best system reliability and highest annual net income, but requires higher investment. The static payback period of investment is slightly different for the three schemes.