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    Research & Analysis
  • Research & Analysis
    Analysis on the Influence of Depth Waste Heat Utilization on Boiler
    Wu Huadong, Shen Yingqiang, Duan Lihong, Wang Xinhua, Wang Tao
    2021, 35(5): 301-304,308. https://doi.org/10.19806/j.cnki.fdsb.2021.05.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on different waste heat capacities and different efficiency boundaries, the effect of depth waste heat utilization technology on boiler design parameters was discussed, and a comparison and analysis was conducted on the power supply coal consumption. Results show that the reference temperature should be defined when calculating the boiler efficiency. Heating high-pressure feed water is more effective and efficient than heating low-pressure condensate in reducing the heat consumption of steam turbine. From the perspective of boiler design, it is recommended that the waste heat capacity should not be greater than 30 MW. For the unit with low-moisture bituminous coal adopting depth waste heat utilization technology, the improvement of economy is very limited.
  • Research & Analysis
    Experimental Research on Ignition Characteristics of Pulverized Coal in Swirl Burner of Opposed Boiler
    Guo Qiushi, Chen Anhe, Wang Lulu, Zhang Da, Ren Fuhu, Wang Huan
    2021, 35(5): 305-308. https://doi.org/10.19806/j.cnki.fdsb.2021.05.002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at a typical 600 MW subcritical front and rear wall opposed-fired boiler, the influence of pulverized coal concentration, primary air speed and load on the ignition characteristics of pulverized coal was systematically studied on the basis of field tests. The results show that the Hongran coal used in the test is easy to catch fire and easy to burn out. As the pulverized coal concentration increases, the ignition distances of the D-layer and E-layer burners are shortened, which is more conducive to the ignition and combustion of pulverized coal. When the wind speed becomes lower once, the ignition distance is shortened. As the air speed increases, the ignition distance first becomes larger, and then becomes gentle. Keeping the pulverized coal concentration and primary wind speed unchanged, as the boiler load increases, the ignition distance shows an obvious downward trend.
  • Research & Analysis
    Analysis on the Coupling Strength of a 600 MW Class Turbo-Generator Unit
    Li Wangfan, Xu Jiamin
    2021, 35(5): 309-312,318. https://doi.org/10.19806/j.cnki.fdsb.2021.05.003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A finite element model of the coupling between the low-pressure rotor and the generator rotor for a 600 MW class unit was established. The stress distribution on the coupling was analyzed under rated condition and typical electrical failures. The dangerous positions were determined and the strength checking was carried out. Results show that under rated condition, the torque is mainly transmitted by the static friction force between the end faces of the coupling, and the shear stress of the bolt is small; under typical electrical failures, the torque transmission depends to a large extent on the squeezing of the bolt hole on the end face of the coupling and the bolt screw, and the shear stress of the bolt is large; under different unit states, the dangerous position has a change, so the structure of the stress concentration parts could be optimized reasonably to ensure the safety of the coupling.
  • Research & Analysis
    Design and Research of Intelligent Fouling Detection System for Ultra Supercritical Unit
    Li Hongtao, He Xiunian, Zhao Xueming
    2021, 35(5): 313-318. https://doi.org/10.19806/j.cnki.fdsb.2021.05.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problems of ash fouling and slagging in large scale coal-fired units, an intelligent fouling detection system is designed by measuring heat flux density of water wall with heat flow meter, and analyzing ash deposition and slagging condition on heating surface and air preheater. The system is expected to be able to purge fouling smartly as well as report the operating condition of radiant heating surface with the heat flow distribution of those surfaces which can improve safety and economy of units.
  • Research & Analysis
    Study on Arrangement of Flue Gas Velocity Measuring Points Based on Self-modeling Theory
    Dong Honglin, Zhu Xiaoliang
    2021, 35(5): 319-324. https://doi.org/10.19806/j.cnki.fdsb.2021.05.005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The flow conditions and characteristics of the flue gas in the tail flue with a 90°bend, which was installed between the desulfurizer and the chimney inlet, were investigated. Based on the theory of self-mode region of viscous fluid and the mean value theorem, the regions in the tail flue that represent the enterance velocity of flue gas at different inlet velocity were analyzed. By the comparation of secondary flow lines between different sections from the chimney inlet, the section with uniform distribution of flow lines, no secondary flow and appropriate distance from the chimney inlet was located. Furthermore, the optimal arrangement of measuring points was determined by the analyses and comparations of isovelocities distribution on this section. Results show that the number of measuring points arrangement for the large tail flue with a 90°bend is greatly reduced by the utilization of the measuring points arrangement proposed and the measuring accuracy is improved.
  • Research & Analysis
    Research on the Prevention and Control of Ash Deposit in the Annular Air Box of 1 000 MW Power Plant Boilers
    Qiu Lichun, Hu Qing, Zhang Haidan, Li Yanmeng, Zhang Guangxue
    2021, 35(5): 325-328. https://doi.org/10.19806/j.cnki.fdsb.2021.05.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A solution to preventing the ash deposit in annular air boxes was proposed for the 1 000 MW ultra-supercritical wall opposed firing boilers. The purging air pipe was set horizontally through the secondary air box with the hot primary air used as the gas source and the holes opened at certain intervals. Combined with the flow field theoretical calculation of the purging air, the hot state on-line continuous cleaning of the ash deposit in the annular air box was achieved, which effectively solved the ash deposit problem and unchanged the combustion and plant electricity. The research can save the manual cleaning cost and improve the unit operation safety.
  • Research & Analysis
    Flow Field Optimization for a Flue Gas Duct at Induced Fan Outlet of a 600 MW Unit
    Hu Shanmiao, Wei Hongqi, Sha Yuanchao, Wang Chao
    2021, 35(5): 329-333. https://doi.org/10.19806/j.cnki.fdsb.2021.05.007
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Numerical simulations were conducted on the flow field of a flue gas duct at the induced fan outlet in a 600 MW unit, and optimization retrofits were carried out by adding guide plates and setting up chamfers. Following parameters were used to analyze and evaluate the the flow field of the duct, such as the velocity, the turbulent kinetic energy and the coefficient of velocity deviation, after which, the reliability of simulation results were validated through experiments. Results show that after the optimization, the local high speed region and the low speed vortex region are significantly reduced, the turbulence kinetic energy is greatly reduced, and the flow uniformity is effectively improved. The coefficient of velocity deviation of the cross section is decreased from 49.8% to 14.9%, while the overall flue resistance of the duct is decreased by 255 Pa. This presents a good effect of the optimization.
    • New Energy
  • New Energy
    Thermophysical Properties of Solar Salt and Its Application in Solar Thermal Power Generation
    Wang Jinliang, Wu Huadong
    2021, 35(5): 334-338. https://doi.org/10.19806/j.cnki.fdsb.2021.05.008
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Thermophysical properties of solar salt were introduced, and different correlations of convection heat transfer for molten salt tube were compared. Meanwhile, researches were conducted on following problem existing in solar thermal power generation with molten salt, such as degradation, corrosion and oxynitride (NOx) emission, etc. Results show that Gnielinski correlation and Dittus-Boelter correlation are not suitable for the application of molten salt in solar thermal power generation, and the temperature of metal material in molten salt should be controlled.
    • Design & Manufacture
  • Design & Manufacture
    The Main Production Points of the Horizontal Split Large Plate Girder for Tower Boiler
    Xie Na
    2021, 35(5): 339-343. https://doi.org/10.19806/j.cnki.fdsb.2021.05.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Large horizontal split plate girder for a large thermal power boiler is super-long, super-wide and super-heavy, and its manufacturing difficulties are the narrow tolerance range of arch camber, synchronous arching of upper and lower plate girder, and concentricity of holes in the horizontal split surface. The manufacturing process of large plate girder is discussed, the corresponding measures are taken in the aspects of material preparation, blanking, drilling, assembly, welding, stiffener assembly, turning over and other aspects which ensure the quality and safety of the large plate girder.
    • Material Technology
  • Material Technology
    Comparative Study on Steam Oxidation Resistance of Shot Peened and Non-shot Peened S30432 Steel
    Ge Lingfeng, Feng Pufeng, Lü Xiangdong, Sui Xin, Shao Lei, Liu Hanghang, Zhang Xinglong
    2021, 35(5): 344-348. https://doi.org/10.19806/j.cnki.fdsb.2021.05.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The supercritical steam oxidation behavior of the shot peened and non-shot peened S30432 steel at the condition of 635℃ and 25 MPa was studied. After oxidation for 3 000 h, the morphology, microstructure and element distribution of the surface and the cross-section of the oxide film were determined, and the structure and phases of the oxide film were characterized. The results show that both shot peened and non-shot peened S30432 steel follow the law of power exponent oxidation and the steam oxidation resistance of shot peened S30432 steel is significantly better than that of non-shot peened S30432 steel. Shot peening can facilitate the formation of dense chromium-rich oxide layer. The oxide film formed on the surface of shot peened S30432 steel is (Fe, Cr, Ni)3O4 and a small amount of Fe2O3 and Fe3O4, while the outer layer of the oxide film of non-shot peened S30432 steel is Fe2O3 and Fe3O4, and the inner layer of oxide film is mainly (Fe, Cr, Ni) 3O4.
  • Material Technology
    Fracture Failure Analysis of High Pressure Governing Valve Bolt in a Steam Turbine
    Gao Beibei, Chen Tuo, Li Debo
    2021, 35(5): 349-352. https://doi.org/10.19806/j.cnki.fdsb.2021.05.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of the fracture failure of a high pressure governing valve bolt made by 20Cr1Mo1VNbTiB in a 600 MW unit steam turbine, the fracture reason of the bolt was analyzed through macroscopic analysis, chemical composition analysis, metallographic analysis, fracture analysis and hardness test. Results show that the fracture of the bolt is caused by the combined action of following factors, such as the stress concentration at the root of threaded teeth resulted from machining defects, the worse plasticity of the bolt due to the improper control of chemical elements in smelting process, and the ageing of material during long time operation under high temperature and high pressure.
    • Automatic Control
  • Automatic Control
    Ash Fouling On-line Monitoring for Heating Surface in Pulverized Coal Furnace Based on SPCA Model
    Song Guian, Geng Chamin, Ren Shaojun, Si Fengqi
    2021, 35(5): 353-358. https://doi.org/10.19806/j.cnki.fdsb.2021.05.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A sparse principal component analysis (SPCA)model with elastic net constraint was proposed, based on which, an on-line monitoring method was established for the ash fouling on the boiler heating surface. Taking the operation data of a power plant as the research object, a comparison and analysis was conducted on the statistical indicators, and the ash fouling distribution of each heating surface was obtained through contribution graph. Results show that the ash fouling condition of the heat surface can be well monitored with the on-line monitoring method, and SPCA model is more accurate than traditional principal component analysis (PCA) model in locating the ash fouling of the heating surface.
    • Operation & Retrofit
  • Operation & Retrofit
    Analysis and Application on Flue Gas Duct Resistance Reduction for Stall of the Induced Draft Fan
    Wang Shaomin, Li Deyong, Yan Shu, Shi Shaoping, Mu Yanfei
    2021, 35(5): 359-364. https://doi.org/10.19806/j.cnki.fdsb.2021.05.013
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To slove the problem that the induced draft fan of a 550 MW unit in a coal-fired power plant stalled after the ultra-low emission retrofit, the tests of pressure drop characteristics were carried out for the flue gas exhaust system, and the prediction model of pressure drop was established. After which, the ducts of the desulfurization system were optimized through numerical simulation. Results show that the stall of the induced draft fan is caused by the increase of the actual operation resistance of the desulfurization system relative to the design value. Meanwhile, compared with the the theoretical stall line, the actual operation stall line shifts to the lower right direction. With the optimization of the ducts of the desulfurization system, the stall of the induced draft fan can be solved.
  • Operation & Retrofit
    Optimization and Adjustment Experiment on a 62 000 m3/h Atmospheric CFB Gasifier
    Gong Shishang, Chen Lu, Chen Jiaquan, Zheng Yong, Zhang Zhili, Shen Baofu
    2021, 35(5): 365-369. https://doi.org/10.19806/j.cnki.fdsb.2021.05.014
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking a 62 000 m3/h circulating fluidized bed (CFB) gasifier as the research example, based on the stable operation of the gasifier without coking, the effects of following influence factors on the constituents of coal gas, the heating value of coal gas and the carbon content of slag were studied, such as the size distribution of raw coal particles, the temperature of the lower part in furnace, the ratio of air to coal, the ratio of steam to coal and the oxygen flow rate, after which, a comprehensive adjustment was carried out. Results show that by adjusting each of the influence factors, both of the heating value of coal gas and the contents of effective constituents can be improved to a certain extent, and the carbon content of slag can be reduced significantly. By adjusting all influence factors at the same time, under 75% and 100% rated load, the heating value of coal gas can be increased to 6 504-6 603 kJ/m3, and the carbon mass fraction of slag can be reduced to 13.45%-16.27%. The adjustment presents a good effect, which may serve as a reference for the economic operation adjustment of similar gasifiers.
  • Operation & Retrofit
    Comparison of Flue Gas Waste Heat Utilization Schemes for 1 000 MW Units
    Zhang Jian, Zhen Hui, Xiang Baixiang, Li Yan, Huang Jun, Wang Peng, Wang Dapeng
    2021, 35(5): 370-374. https://doi.org/10.19806/j.cnki.fdsb.2021.05.015
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to make full use of the waste heat of exhaust gas, the inlet feed water of No.0 high-pressure heater, drain water of No.0 high-pressure heater, condensate water or refrigerant water of the original system were used as coolant to reduce hot primary air temperature. The results show that the phase-change heat transfer of drain water has the highest cost performance. On the basis of reducing primary air temperature, two utilization modes of primary economizer with primary air heater and whether the low-pressure heater exchanges heat without primary air heater were compared. The results show that the cost can be greatly reduced by the installation of primary air heat ex-changer and primary air heater at 0 m of boiler, and the maximum coal saving is expected to be 2.2 g/(kW·h).