Archive

  • Select all
    |
    Boiler Technology
  • Boiler Technology
    Experimental Study on Coal Lateral Dispersion Coefficients of a 600 MW Supercritical Circulating Fluidized Bed Boiler
    YAN Jin, LU Xiaofeng, ZHENG Xiong, XUE Rui, CUI Xiaobo, LEI Xiujian
    2021, 41(7): 525-532. https://doi.org/10.19805/j.cnkij.cspe.2021.07.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking the distribution characteristics of flue gas components as the criterion, thermal field tests on the characteristics of secondary air (SA) penetration and coal particle lateral dispersion were conducted on the first 600 MW supercritical circulating fluidized bed (CFB) boiler in the world. Combined with 2D dispersion model, the mass concentration distribution of coal particles in the cross-section was predicted. Results show that the penetration depth of SA on the outer side wall is 3-4 m and the lateral dispersion is weaker. The lateral dispersion coefficient of coal particles is about 0.24 m2/s. When the coal is injected into the furnace for 15 s, the uniformity of coal particle distribution in the bed can be significantly improved.
  • Boiler Technology
    Combustion Optimization for Reducing CO Emission in an Opposed Swirl Firing Boiler
    HE Xiang, MA Dafu, JIN Jing
    2021, 41(7): 533-541. https://doi.org/10.19805/j.cnkij.cspe.2021.07.002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the phenomenon of high CO mass concentration at the inlet of air preheater and near the side wall in a 660 MW opposed swirl firing boiler, an analysis was conducted combined with on-site survey and performance test data, in addition, an experiment of combustion optimization was carried out. On the basis of static combustion adjustment, the functional relationship between the opening of layer-operated secondary air damper on C layer and unit load was established, and the opening of the damper under the original logic was corrected according to unit load. Results show that reasons for high CO mass concentration at the inlet of the air preheater and near the side wall are low fineness of pulverized coal, unreasonable local adjustment of the burners and separated over fire air (SOFA), and excessive opening of layer-operated secondary air damper on C layer. Moreover, under the condition of high unit load, CO mass concentration at the inlet of the air preheater can be reduced to less than 300 mg/m3 while that near the side wall can be decreased from above 58 000 mg/m3 to less than 12 000 mg/m3. After logic optimization, CO emission of the unit in dynamic process is reduced, which shows that the effect of combustion optimization is obvious.
    • Steam Turbine and Gas Turbine
  • Steam Turbine and Gas Turbine
    New Progress and Development Direction of Steam Turbines in China
    SHI Jinyuan, YANG Hong, ZHANG Hongtao, FANG yu, LI Jun, WANG Baolai
    2021, 41(7): 542-550. https://doi.org/10.19805/j.cnkij.cspe.2021.07.003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The new development for steam turbines in China between 2010 and 2019 with remarkable achievements and next development direction were reviewed from the perspective of the development of steam turbines. The foreign progress of 700 ℃ thermal power steam turbines and 1 700 MW grade nuclear power steam turbines were briefly described. The technology development characteristics and new progress for the thermal power steam turbines, nuclear power steam turbines and industrial steam turbines in China were summarized. Then the future development directions of steam turbines were put forward, including steam turbines with a power generation efficiency of more than 50%, 1 900-2 200 MW nuclear power steam turbines as well as full speed 1 450-1 550 mm and half speed 2 000-2 300 mm long blades. Results show that new achievements of China's high parameter 660-1 240 MW thermal power steam turbines, 1 000-1 755 MW nuclear power steam turbines, industrial driving and generation steam turbines, steam parameter and power of large capacity steam turbines as well as long blade of the final stages have achieved in the pastdecade. And the productivity for independent design, local manufacture and batch production of the thermal power steam turbines, nuclear power steam turbines and industrial steam turbines are basically formed in China.
    • Environmental Protection Technology and Equipment
  • Environmental Protection Technology and Equipment
    NOx Prediction Model Based on Artificial Fish Swarm-Radial Basis Function Neural Network
    JIN Xiuzhang, YU Jing, LIU Yue
    2021, 41(7): 551-557. https://doi.org/10.19805/j.cnkij.cspe.2021.07.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem that NOx concentration at the inlet of SCR system for coal-fired power plant was delayed and difficult to measure, a prediction model based on artificial fish swarm algorithm (AFSA) optimized radial basis function neural network (RBFNN) was proposed. The input variables of the model were determined by mutual information while the delay time was estimated by K-nearest neighbor mutual information. Moreover, a prediction model of the auxiliary variables and dominant variables of phase space reconstruction was established by using RBFNN with strong generalization ability, and the optimal parameter combination of RBFNN was determined by AFSA, which can overcome the influence of unknown input rules and random parameter. Finally, the AFSA-RBFNN prediction model was compared with RBFNN and PSO-RBFNN prediction models. Results show that the root mean square error, the average absolute percentage error and the running time of the AFSA-RBFNN prediction model are minimum, indicating that its generalization ability and prediction accuracy are obviously better than those of other models, and the model can solve the problems of local convergence and long running time of the particle swarm optimization algorithm.
  • Environmental Protection Technology and Equipment
    Economic Analysis of the Carbon-Based Catalytic Heat Source Regeneration Scheme for Coal-Fired Power Stations
    CHENG Wenyu, LIU Mengning, XING Deshan, XU Yun, XU Haojie
    2021, 41(7): 558-564. https://doi.org/10.19805/j.cnkij.cspe.2021.07.005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking a 350 MW supercritical unit as an example, the scheme of extracting reheat steam as the regeneration heat source of carbon-based catalyst was proposed, and the high temperature steam after heat exchange was preferentially substituted for deaerator extraction (scheme 1) or feedwater pump turbine extraction (scheme 2) for economic analysis. Results show that at 100% THA load, the absolute internal efficiency of the steam turbines of the two schemes is reduced by 2.5% and 1.8%, and the standard coal consumption for power supply is increased by 16.6 g/(kW·h) and 11.9 g/(kW·h) respectively; at 75% THA load, the absolute internal efficiency of the steam turbine decreases 4% and 2.5%, the standard coal consumption for power supply increased by 13.4 g/(kW·h) and 17 g/(kW·h) respectively. According to the characteristics of the unit, a unit with a large proportion of high-load operation can choose scheme 2, and a unit with a large proportion of low-load operation can choose scheme 1.
  • Environmental Protection Technology and Equipment
    Simulation and Optimization of Carbon Dioxide Capture Process for Flue Gas in Power Plants Based on Vapor Compression and Split Flow
    GUO Liheng, DING Yudong, LIAO Qiang, ZHU Xun, WANG Hong
    2021, 41(7): 565-571. https://doi.org/10.19805/j.cnkij.cspe.2021.07.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Two carbon dioxide capture processes based on the vapor compression and split flow processes were established by Aspen Plus software, and the effects of rich solvent split fraction, vapor compressor outlet pressure and split rich solvent inlet position on system energy consumption were simulated. Results show that there is an optimal relationship between rich solvent split fraction and outlet pressure of vapor compression, so as to achieve the maximum heat recovery from stripper vapor. The reboiler load per unit CO2 capture capacity can be reduced to 2.231 GJ/t and 2.078 GJ/t respectively by the two steam compression and split flow processes. Compared with traditional CO2 capture process, the total energy consumption of steam compression split flow process 1 and steam compression split flow process 2 could be reduced by 21.0%-21.6% and 13.0%-17.7% respectively. Considering the total energy consumption of the carbon capture and compression system, the process 1 which directly exchanges heat with the rich solvent after the top steam compression has better energy saving effect.
    • New Energy
  • New Energy
    Research on Noise Reduction Mechanism of a Coupled Bionic Airfoil
    XIE Ming, YANG Ailing, CHEN Eryun, ZHANG Wenqing
    2021, 41(7): 572-580. https://doi.org/10.19805/j.cnkij.cspe.2021.07.007
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the NACA0018 airfoil, the WSR airfoil was formed by coupling wavy leading edge, serrated trailing edge and ridged surface. The flow field and noise characteristics of WSR airfoil at different Reynolds numbers and angles of attack were studied by large eddy simulation and FW-H method.Results show that at low angle of attack and low Reynolds number, the WSR airfoil can reduce the instability noise by 5 dB. At high angle of attack, the serrated trailing edge structure would intensify flow mixing at trailing edge, change wake vortex structure, reduce vorticity at trailing edge of airfoil, and finally noise would be reduced by 8 dB.
  • New Energy
    Influence of Different Suction Strategies on Dynamic Stall Characteristics of Wind Turbine Airfoil
    CHEN Weisheng, SUN Xiaojing
    2021, 41(7): 581-587. https://doi.org/10.19805/j.cnkij.cspe.2021.07.008
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking NACA0012 airfoil as an object of research, the influence of leading edge suction on stall characteristics of airfoil at high Reynolds number was simulated using Transition SST turbulence model and Simple algorithm, and four different suction strategies were designed, so as to analyze the effects of different suction strategies on airfoil dynamic stall, and compare the energy consumption required of the four. Results show that at the same momentum coefficient, suppression of dynamic stall vortices by suction control is better than that of jet control. Compared with jet control, average lift coefficient of the airfoil can be increased by more than 13%, while the average drag coefficient can be reduced by 80%. The equivalent lift to drag ratio of the airfoil reaches maximum when the strategy of Sin function with the opening downward is adopted.
  • New Energy
    Influence of Slotted Wing with Variable Curvature on Aerodynamic Performance of Vertical Axis Wind Turbine
    ZHANG Qiang, MIAO Weipao, LI Chun, ZHANG Wanfu
    2021, 41(7): 588-595. https://doi.org/10.19805/j.cnkij.cspe.2021.07.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Slotted wings with different curvature were constructed by changing the ratio of long axis and short axis of the elliptic, so as to study the influence of different opening widths of the gap and curvature on power factors and starting characteristics of vertical axis wind turbine. Results show that at low tip to speed ratio and high angle of attack, the fluid reattaches to suction surface owing to the airfoil with the slotted wing, which delays the flow separation and reduces the torque fluctuation, furthermore, the torque coefficient is significantly improved. Compared with the original airfoil, the optimal tip to speed ratio of the airfoil with the slotted wing is relatively lower, and operating environment of the wind turbine is more stable.
    • Material Research
  • Material Research
    Oxidation Behavior of GH750 and Haynes 282 in Steam at 750 ℃
    NI Yifan, YANG Changshun, WANG Miaomiao
    2021, 41(7): 596-601. https://doi.org/10.19805/j.cnkij.cspe.2021.07.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Oxidation behaviors of GH750 and Haynes 282 in steam at 750 ℃ were investigated. Oxidation kinetics of two alloys was obtained by weight gain method, the morphology and element distribution of the oxides were analyzed by scanning electron microscope and energy dispersive spectroscopy, and the phase of oxides on alloy surface was analyzed by X-ray diffraction. Results show that oxidation kinetics of the two alloys obeys the parabolic law approximately, moreover, the steam oxidation resistance of GH750 is superior to that of Haynes 282. Oxides formed on the surfacee of GH750 and Haynes 282 are mainly composed of Cr2O3 and a small amount of (Ni,Co)Cr2O4 and TiO2. An internal oxidation zone mainly composed of Al2O3 and TiO2 exists at oxide/substrate interface, and an obvious chromium depletion region appears in the substrate near the interface.
  • Material Research
    Corrosion Behavior of Heat-resistant Materials in Supercritical Carbon Dioxide Environment
    GUI Yong, LIANG Zhiyuan, GUO Tingshan, WANG Mengyao, ZHAO Qinxin, WANG Shuo
    2021, 41(7): 602-608. https://doi.org/10.19805/j.cnkij.cspe.2021.07.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Five typical heat-resistant materials T91, VM12, Super 304H, Inconel 617 and Sanicro 25 were selected as the experimental materials, and the supercritical carbon dioxide corrosion tests were conducted at 600 ℃ and 15 MPa. Analytical balance was used to obtain the weight gain changes of heat-resistant materials. Raman spectrometer, X-ray diffractometer and glow discharge spectrometer were employed to characterize the phase and composition of corrosion products on the surface of heat-resistant materials. Electron microscope was used to observe the surface and cross-section morphology.Finally, the corrosion behavior of heat-resistant materials was analyzed. Results show that T91 and VM12 obey the parabolic corrosion kinetic law, while Super 304H, Inconel 617 and Sanicro 25 have no obvious weight gain and no obvious law.The weight gain is inversely proportional to the Cr content of heat-resistant materials.The heat-resistant materials undergo oxidation and carburization reactions in a high-temperature supercritical carbon dioxide environment.T91 and VM12 have no Cr-poor phenomenon, while Super 304H, Sanicro 25 and Inconel 617 have obvious Cr-poor areas, and the thickness of Cr-poor areas from small to large is Inconel 617
    • Hydroturbine Technology
  • Hydroturbine Technology
    Chaos Analysis on Acoustic Emission Signals of Francis Turbine Under Cavitation
    LIU Zhong, JIANG Ying, ZOU Shuyun, CHEN Ying, LIU Zhen, LI Zhipeng
    2021, 41(7): 609-616. https://doi.org/10.19805/j.cnkij.cspe.2021.07.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In view of the strong nonlinearity and nonstationarity of acoustic emission signal from hydraulic turbine under cavitation, a chaotic analysis method of acoustic emission signals was established, and the chaotic characteristics and the change law of acoustic emission signals from Francis turbine under cavitation were studied. A series of cavitation tests on a model Francis turbine were conducted, and the acoustic emission signals of typical measuring points under different cavitation conditions were collected. The correlation dimension (DC) and the Largest Lyapunov Exponent(LLE) of the reconstructed signal were calculated. Variation laws of these two chaotic characteristic parameters under cavitation state of hydraulic turbine were analyzed, and the corresponding relationship between the chaotic characteristic parameters of hydraulic turbine cavitation acoustic emission signal and the cavitation state was clarified. Results show that DC and LLE can describe the cavitation state qualitatively and the cavitation degree quantitatively. Also, the influence of unit speed on two chaotic characteristics is greater than that of guide vane open degree.