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  • Research & Analysis
    Study on Physicochemical Properties of Mn-Ce-Fe-Co-Ox Catalyst for Simultaneous Removal of NOx and Mercury at Low Temperatures
    Wu Shang, Guo Zhigang, Li Yinsheng, Wu Linhu
    2020, 34(4): 223-228. https://doi.org/10.19806/j.cnki.fdsb.2020.04.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With the Mn-Ce-Fe-Co-Ox catalyst prepared by in-situ generation method, researches were conducted on the catalytic performance in simultaneous removal of NOx and mercury in a fixed bed system under the atmosphere of simulated selective catalytic reduction (SCR) flue gas, of which the physicochemical properties were analyzed through various characterization technologies. Results show that the Mn-Ce-Fe-Co-Ox catalyst presents outstanding performance in simultaneous removal of NOx and mercury at low temperatures, and the removal efficiency for NOx and mercury can reach 83.7% and 91.5% simultaneously at 170℃. Dense and disordered active filamentous structures cover the surface of the oxides, which improve the specific surface area and pore structure of the catalyst. Four groups of H2 reduction peaks appear in the H2 temperature-programmed reduction (TPR) experiment at 161.8488.3℃, indicating good reduction capability of the catalyst at low temperatures. The decomposition weight loss ratio is lower than 6.56% at 300600℃, exhibiting high resistance of the catalyst to elevated temperatures.
  • Research & Analysis
    Energy and Exergy Analyses of a 135 t/h CFB Boiler
    Song Guohui, Wang Hongmei, Zhu Liang, Zhang Siwen, Cui Xiaobo
    2020, 34(4): 229-234. https://doi.org/10.19806/j.cnki.fdsb.2020.04.002
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    To analyze the effects of the conditions with and without high-pressure heaters on the energy efficiency and exergy efficiency of a 135 t/h circulating fluidized bed (CFB) boiler, a study was conducted on the boiler body and boiler system through energy and exergy analyses. Results show that the energy efficiency and exergy efficiency of the boiler system depend on those of the boiler body. Under the same steam flow, the condition with high-pressure heaters is beneficial to the energy efficiencies of the boiler body and system, but is against their exergy efficiencies. The proposed calculation model of boiler's exergy losses could serve as a reference for further researches.
  • Research & Analysis
    Numerical Simulation of an Adjustable Pulverized Coal Distributor
    Xin Li, Shi Hongfei, Lü Weizhi
    2020, 34(4): 235-240. https://doi.org/10.19806/j.cnki.fdsb.2020.04.003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Numerical simulations were conducted on the internal flow field of a coal mill and an adjustable pulverized coal distributor with FLUENT software to study the flow characteristics of gas-solid two-phase flow in the pulverized coal distributor, and to verify the distribution effect. Results show that after installing the pulverized coal distributor, graded collection of coal powder can be achieved by using shutter rings and adding a thick-light phase regulating valve, which can effectively improve the distribution uniformity of the pulverized coal. For differently sized particles, efficient redistribution can be realized via the pulverized coal distributor, and with the increase of particle diameter, the distribution effect becomes better and the backflow of coal powder is limited.
  • Research & Analysis
    Analysis of High Steam Temperature Deviation at Inlet of a Low-temperature Reheater in Russia-made Supercritical Unit
    Liu Honghai, Zhang Lei
    2020, 34(4): 241-244. https://doi.org/10.19806/j.cnki.fdsb.2020.04.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the phenomenon of large deviation of inlet steam temperature existing in the low-temperature reheater system of a 500 MW Russia-made unit, the causes leading to the problem of large steam temperature deviation were researched, through analysis on the arrangement and operation parameters of the low temperature reheater system, combined with field test and simulation calculation, by studying the effects of flue gas temperature and steam flow on the inlet steam temperature. Corresponding countermeasures were proposed on the basis of above analyses.
    • Nuclear Technology
  • Nuclear Technology
    Study on Model Selection of Seismic Qualification Test System for the 3rd Generation Passive Nuclear Power Plant
    Shang Heng, Ge Lei
    2020, 34(4): 245-247. https://doi.org/10.19806/j.cnki.fdsb.2020.04.005
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    An analysis was conducted on the requirement of seismic qualification test according to the seismic response spectrum on different floors in the 3rd generation passive nuclear power plant, while the equipment need to be qualified by seismic test were classified in terms of major parameters, such as mass and dimension, etc, by simultaneously considering the features of the seismic simulation test facilities. The scheme for model selection of seismic simulation system was finally recommended for the 3rd generation passive nuclear power plant.
    • Material Technology
  • Material Technology
    Investigation on Elements Segregation and Microstructure Evolution during Weld Solidification of Nickel-based Superalloy Inconel 740H
    Zhao Shuangqun, Li Qiang, Fu Rui, Wang Yanfeng
    2020, 34(4): 248-252. https://doi.org/10.19806/j.cnki.fdsb.2020.04.006
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    The solidification process and microstructure evolution of the weld metal in the GH750 superheater tube joints welded with Nickel-based welding wire Inconel 740H were investigated by means of scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and thermodynamic calculation. Results show that obvious segregation exists in the weld metal during solidification process when Inconel 740H welding wire is used. Titanium and Niobium are the major segregation elements, and the segregation generally happens in the interdendritic region. The analysis results of element segregation agree well with those of thermodynamic calculation. After being aged for 3 000 h at 760℃and 800℃, few γ' phases precipitate on the dendritic trunk while more γ' phases precipitate in the interdendritic region of solidified Inconel 740H, where a small quantity of η phases are observed.
    • Environmental Technology
  • Environmental Technology
    Study on Factors Influencing the Design of Rated Load Range for the Waste Heat Boiler in a Waste Incineration Power Plant
    Xie Jun
    2020, 34(4): 253-256,261. https://doi.org/10.19806/j.cnki.fdsb.2020.04.007
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the principle of radiant heat transfer and convective heat transfer, taking a mechanical grate furnace and the supporting waste heat boiler as the research objects, characteristic diagrams were drawn for the superheater with different parameters through thermodynamic calculations. Meanwhile, the effects of main steam parameters and the grate furnace on the design load of the waste heat boiler were analyzed, thus to obtain the design load range for the waste heat boiler under different conditions of waste heat values, treatment scales and steam parameters.
  • Environmental Technology
    Study on Application of CCHP Systems with Low Concentration Gas
    Chen Jing, He Yong, Deng Mian, Zhu Kai
    2020, 34(4): 257-261. https://doi.org/10.19806/j.cnki.fdsb.2020.04.008
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    According to the energy demand of a coal mine in different periods, based on the cascade utilization of energy, the characteristics of a combined cooling, heating and power (CCHP) system with low concentration gas was introduced, in which, the power generation system is of the two-stage kind. Operation results show that when the pure gas reaches its rated volume flow (36 m3/min), the power generation of both the back-pressure steam turbine and condensing steam turbine can achieve their rated values, indicating expected effect of the CCHP system. In the period of power generation, the system can also provide steam to meet heating requirement of coal mines, proving the system to have remarkable energy saving effect, which therefore has a good application prospect.
    • Design & Manufacture
  • Design & Manufacture
    Design Optimization of the MGGH Flue System for 600 MW Coal-fired Units
    Wu Hao, Wei Hongqi, Zhou Shuai, Zhao Chuanhui
    2020, 34(4): 262-267,278. https://doi.org/10.19806/j.cnki.fdsb.2020.04.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The flow field in the media gas-gas heater (MGGH) flue system of a 600 MW coal-fired power plant was simulated using FLUENT software, where a guide plate was subsequently added to optimize the flow fields at the inlet of both the desulfurization tower and MGGH as well as in relevant flue ducts, following which the effects of the newly-added guide plate on above flow fields were analyzed. Results show that the pressure drop in the flue gas cooler and reheater is in good agreement with the experimental data. Via the guide plate, the velocity unevenness could be controlled within ±0.2 at the inlet of the desulfurization tower, flue gas reheater and flue gas cooler, and the deviation coefficient of inlet velocity is kept to be lower than 10%. The reasonable design of guide plate can effectively eliminate the eddy and flow field separation caused by elbow and variable sections, and can make the flue gas flow into the MGGH and desulfurization tower more evenly.
    • Operation & Retrofit
  • Operation & Retrofit
    Field Test Research on the Near-wall Reduction Atmosphere in a Tangentially Fired Boiler
    Jiang Yu, Li Debo, Zhou Jielian, Chen Tuo, Feng Yongxin, Zhong Jun, Su Zhanqing
    2020, 34(4): 268-273. https://doi.org/10.19806/j.cnki.fdsb.2020.04.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The near-wall volume fractions of H2S, CO, NO and O2 in the main burner area of a 320 MW tangentially fired boiler were measured at 60% and 100% boiler load, while the variation law of the near-wall reduction atmosphere was analyzed by adjusting the working conditions. Results show that high volume fraction of CO is detected near water wall in the furnace at different boiler loads and in different air distribution modes, indicating that strong reduction atmosphere exists in that area, which is the main cause of high-temperature corrosion. In the process of operation, it is suggested increasing the boiler operation oxygen, controlling the sulfur content in the coal by properly blending with other kinds of fuel, so as to prevent the water wall from high-temperature corrosion resulted from being exposed in reduction atmospheres for a long time.
  • Operation & Retrofit
    Key Strategies for Self Combustion Turning of the 9E Gas Turbine DLN1.0 System
    Hong Yaguang, Yao Weimin, Yin Chunhong
    2020, 34(4): 274-278. https://doi.org/10.19806/j.cnki.fdsb.2020.04.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction was presented to the structure and combustion mode of DLN 1.0 combustion chambers equipped in 9E gas turbines. The key strategies of combustion tuning with step-by-step explanation were presented according to the self tuning experience of a power plant, emphatically explaining the method to determine the optimum fuel ratio to achieve stable combustion and low pollutant emission simultaneously. This may serve as a reference for localization of combustion tuning technologies.
  • Operation & Retrofit
    Retrofit Research for the Flow Passage of a 300 MW Subcritical Steam Turbine Unit
    Xu Xing
    2020, 34(4): 279-282. https://doi.org/10.19806/j.cnki.fdsb.2020.04.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the flow passage retrofit status of domestic subcritical steam turbine units. Based on the performance of a 300 MW subcritical steam turbine unit, the following two retrofit schemes were compared and analyzed from the aspects of technical route and performance index, i.e. the overall flow passage retrofit scheme and the partial flow passage retrofit scheme, for which, corresponding suggestions were proposed. Results show that the overall flow passage retrofit scheme is more economical, which is more adaptable to future developments. This may serve as a reference for the implementation of flow passage retrofit schemes for subcritical steam turbine units.
  • Operation & Retrofit
    Influence of Abnormal Coal Feeder Operation on the Safety of a Power Unit and the Corresponding Solutions
    Wang Jinsong
    2020, 34(4): 283-285,291. https://doi.org/10.19806/j.cnki.fdsb.2020.04.013
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In view of the unstable working condition of a power unit resulted from abnormal operation of the coal feeder, an analysis was conducted, after which, the problem was found to be caused by that the centralized control room is not able to accurately collect the status signals of the coal feeder, and the metering system is out of correctness. The problem was finally solved by adding an external function patch and simulating the factual coal checkout, which may serve as a reference for power units with similar problems.
  • Operation & Retrofit
    Combustion Optimization Analysis for Reducing CO Volume Fraction in a 660 MW Ultra-supercritical Swirl Opposed Boiler
    Huang Guohui
    2020, 34(4): 286-291. https://doi.org/10.19806/j.cnki.fdsb.2020.04.014
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Combustion adjustments were conducted for a 660 MW ultra-supercritical swirl opposed boiler to solve the problem of high-temperature corrosion caused by high CO volume fraction in the flue gas and near the water wall, and to improve the unit economy subsequently. By optimizing the pulverized coal properties of C mill, and adjusting the openings of the overfire air damper, the secondary air damper inside C mill and the secondary air damper outside C mill, etc., the secondary wind speed of C mill was reduced, the ignition of pulverized coal was optimized while the burnout rate was improved. After combustion optimization, the CO volume fraction at the inlet of air preheater has been reduced by 90%, and the CO volume fraction near the wall drops accordingly. The average boiler efficiency in the verification test is 93.26%, 1.02 percentage points higher than the pre-repair test, and 0.57 percentage points higher than the post-repair test.
  • Operation & Retrofit
    Combustion Adjustment for Reducing the Thermal Deviation in a 600 MW Supercritical Swirl Opposed Boiler
    Zhong Wei
    2020, 34(4): 292-296. https://doi.org/10.19806/j.cnki.fdsb.2020.04.015
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of large thermal deviation between the left and right side of a 600 MW boiler unit, an analysis was conducted on the operation data and test data, after which, combustion adjustments were carried out. Results show that the problem is caused by the higher flow rate of secondary air on the right side, leading to elevated flame center and higher heat absorption on the right side. At the same time, larger amount of flue gas on the right side leads to the higher heat absorption on the convective heating surface in the steam water system, resulting in higher deviation of the first and second desuperheating water flow between the left and right side.