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    Power] Equipment and System
  • Power] Equipment and System
    Research on System Correction of Performance Test for Double-reheat Steam Turbine
    ZHAO Wen, YANG Yu, LIU Wei, HAN Huai-yuan
    2023, 43(1): 1-6. https://doi.org/10.19805/j.cnki.jcspe.2023.01.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Calculation methods of extraction steam pressure and enthalpy in system correction of performance test for typical thermal system configured double-reheat steam turbines were researched and corresponding system correction methods were proposed.Design and performance test data of 660 MW and 1 000 MW double-reheat steam turbines were analyzed and the calculation methods were verified to be feasible. Characteristics of turbine cylinder efficiency interception method were compared with stage efficiency interception method.Resultsshow that it is better to adopt turbine cylinder efficiency interception based on test expansion line method under performance test system correction.
  • Power] Equipment and System
    Thermodynamic Design and Numerical Simulation of a Radial-flow Turbine for Ammonia-Water Mixture
    CHENG Zi-yang, WANG Jian-yong, XIAO Bo, CAO Yue, WU Chuang, WANG Jiang-feng
    2023, 43(1): 7-13. https://doi.org/10.19805/j.cnki.jcspe.2023.01.002
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    To better understand the ammonia-water mixed working fluid turbine and improve the circulatory system and overall performance of the Kalina system, a one-dimensional thermodynamic design of the turbine was conduced. The BladeGen, TurboGrid and ANSYS CFX software were used for three-dimensional model numerical simulations. One-and three-dimensional methods were compared with the case in the reference, then the results of one-dimensional thermodynamic calculation and three-dimensional model numerical simulation of the turbine were compared.Resultsshow that the performance of the radial-flow ammonia-water mixture turbine can be accurately estimated using the thermal design model, which could greatly reduce the calculation cost. The parameters of the turbine obtained by one-dimensional thermodynamic calculation and three-dimensional model simulation are basically the same, and the isentropic efficiencies of the two methods are 84.67% and 88.75% respectively. In the flow path, the fluid flow presents smoothly and uniformly working while in absence of any vortex.
    • New Energy Resources and Energy Storage
  • New Energy Resources and Energy Storage
    Numerical Simulation on Reducing Atmosphere for a 1000 MW Ultra-supercritical Double Tangential Circular Mixed Coal Combustion Boiler
    REN De-jun, CHEN Gang, ZHANG Yin, WANG Xin, XU Jun, JIANG Long, XIANG Jun
    2023, 43(1): 14-23. https://doi.org/10.19805/j.cnki.jcspe.2023.01.003
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    The combustion process in the furnace of a 1 000 MW ultra-supercritical double tangential circular mixed coal combustion boiler was simulated. The effects of the outlet oxygen volume fraction of the furnace on the velocity field, temperature field, CO and H2S volume fraction field were comprehensively investigated by comparing calculation results with field tests.Resultsshow that when the outlet oxygen volume fraction increases, the degree of airflow deflection is weakened, the possibility of high temperature gas corrosion of the water wall is reduced, the pulverized coal combustion in the main combustion zone is more sufficient, and the temperature is higher. The higher oxygen volume fraction will inhibit the reducing atmosphere in the furnace. There is a strong correlation between the reductive gases of CO and H2S, and the volume fractions of CO and H2S both decrease with the increase of the outlet oxygen volume fraction, which is related to the enhancement of oxidizing atmosphere and the weakening of the reduction effect of CO on SO2. Under the condition of full load, the outlet oxygen volume fraction increases from 2.2% to 2.7%, which can inhibit the generation of CO and H2S to a certain extent. When the outlet oxygen volume fraction increases to more than 3.0%, the inhibition is more significant. In order to reduce the risk of high-temperature corrosion of the boiler and take into account NOx emissions, the oxygen outlet content of the furnace should not be lower than 3.0% during actual operation.
  • New Energy Resources and Energy Storage
    Study on the Uniformity of Circulating Loop in a 660MW Supercritical CFB Boiler Based on CPFD Method
    CHEN Hong-wei, HEI Cheng-hao, WANG Jun-wu, SONG Yang-fan, ZHAO Jun-hua, JIA Jian-dong, WANG Xi-guang
    2023, 43(1): 24-33. https://doi.org/10.19805/j.cnki.jcspe.2023.01.004
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    The computational particle-fluid dynamics(CPFD) method was used to simulate the furnace, cyclone separators and lower diplegs of a 660 MW supercritical circulating fluidized bed(CFB) boiler, and the effects of the boiler load, cyclone separator outlet pressure, primary and secondary air distributions, and non-uniform secondary air on the solid flow rate of each circulating loop were analyzed.Resultsshow that the average deviation between the simulated pressure values and the boiler operation data is 9.6% in the stability analysis, and the average relative deviation between the average solid flow rate of the circulating loops and the designed material flow is 9.49%. The solid flow rate of the intermediate circulating loop is higher, and the non-corresponding arrangement of the return inlets and the cyclone separators has little influence on the total solid flow rate of the left and right half boilers. The higher outlet pressure of the cyclone separator has a greater effect on the distribution of the solid flow rate in different circulating loops, but the effect becomes smaller when the outlet pressure is lower. The relative range of the solid flow rate of the cyclone separator under the air distribution ratio of 50∶50 with the best uniformity is 5.97%. When the air volume fraction of the secondary air in the middle of the furnace is reduced to 24%, the relative range will be reduced to 8.45%.
    • Digitalization and Intelligentization
  • Digitalization and Intelligentization
    Improved Linear Active Disturbance Rejection Controller Design and Its Application
    ZHANG Yong, WANG You, XUE Ya-li, LI Zheng
    2023, 43(1): 34-40,55. https://doi.org/10.19805/j.cnki.jcspe.2023.01.005
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    The conventional 1st-order linear active disturbance rejection controller performs slow closed-loop response in large inertia processes at thermal power units. To solve this problem, an improved design method of linear active disturbance rejection control was proposed. Based on the estimation of model information, a compensation structure was applied to fit an extended state observer which observed a similar proportion object and by using the lumped disturbance compensation, the dynamics of the closed-loop system behaved equivalent to the expected open-loop response, and it also showed the capability to reduce disturbance and system uncertanty. Through analysis, the physical definition of each parameter of the controller and its tuning strategy were determined. The control effect and robustness of proposed method were verified using simulation. The proposed method was configured and tested on the water level control of high pressure heater and the superheated steam temperature control of the 1st-stage attemperator of superheater of double-reheat coal-fired power plant.Results show that the improved active disturbance rejection controller can improve the control performance of the system, and the proposed method is conveniently to be implemented and set, which shows positive engineering application potential.
  • Digitalization and Intelligentization
    Rotor Fault Transferable Diagnosis Method for ResNet-LSTM Parallel Networks
    XIANG Ling, ZHANG Xing-yu, HU Ai-jun, BING Han-kun, YANG Xin
    2023, 43(1): 41-47. https://doi.org/10.19805/j.cnki.jcspe.2023.01.006
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    In order to improve the rotor fault identification accuracy under small samples, a rotor fault transferable diagnosis method based on residual network(ResNet) and long short-term memory network(LSTM) was proposed. Firstly, the convolutional layer and pooling layer were used as pre-feature extractors to acquire shallow features of signals. Then the ResNet module was used to extract the spatial features of rotor signals, and the LSTM module was used to extract the temporal features of rotor signals. Finally, the time and space features extracted were fused, and the rotor fault diagnosis was achieved by transferring learning between different working conditions.Resultsshow that this method can improve the performance of fault classification while effectively identify rotor faults, and the diagnosis results are better than the existing intelligent fault transferable diagnosis methods.
    • Green Energy and Low-carbon Technology
  • Green Energy and Low-carbon Technology
    Study on the Emission Characteristics of Sludge Combustion Particulate Matter and the Mechanism of Hg Condensation and Deposition on Its Surface
    ZHANG Liu, JIA Li, WANG Yan-lin, WANG Bi-ru, QIAO Xiao-lei, JIN Yan, XIANG Jun
    2023, 43(1): 48-55. https://doi.org/10.19805/j.cnki.jcspe.2023.01.007
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    Considering that sludge was used as low calorific value fuel in practical application,the combustion and kinetics characteristics of three types of sludge (raw sludge, pickled sludge and devolatilised sludge)were analysed using a thermogravimetric analyser. And then the emission characteristics of particulate matter produced from sludge combustion were studied,the components of particulate matter (PM) and the condensation and deposition mechanisms of Hg on its surface were analysed using SEM-EDS. Results show that the main components of submicron particulate matter (PM1) produced by sewage sludge (SS) combustion are K, Cl, P, S and Fe,while the main components of super-micron particulate matter (PM1~10) are Si, Al, Fe and Ca. Acid washing treatment reduces the emission of sub-micron particulate matter, while devolatilization treatment reduces the emission of super-micron particulate matter. For SS sample, Hg exhibits a dp0 and dp-1 relationship in the free molecular region, which respectively corresponding to the homogeneous nucleation and diffusion mechanisms; the dp-1 relationship occurs in the continuous media region, which corresponding to the surface reaction control mechanism. For SS-A sample, Hg exhibits a dp-2 relationship in the continuous media region, which is controlled by the diffusion mechanism.
    • Integrated Energy System
  • Integrated Energy System
    Performance Analysis of a Heat-Power Synergy System Integrated with Steam Ejectors Under the Full Working Condition
    LIU Rong-tang, WANG Yu, FAN Pei-pei, LIU Ming
    2023, 43(1): 56-64. https://doi.org/10.19805/j.cnki.jcspe.2023.01.008
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    To realize the heat-power decoupling and deep peak regulation of cogeneration units, a heat-power synergy system integrated with steam ejectors was proposed, and the analysis model of the system under the full working condition was established. Taking a 330 MW cogeneration unit as a reference unit, the heat-power synergy system integrated with steam ejectors was used to be the ejector synergy unit, then the operational flexibility and economic characteristic of the two units were compared.Resultsshow that when the heating load is 795 GJ/h, the electric load rate adjustment range of the cogeneration unit and ejector synergy unit is 45.99%-81.75% and 15.78%-100% respectively, which indicates the ejector synergy unit has higher operational flexibility and outstanding deep peak regulation capability. The overall economic advantage of the ejector synergy unit in the peak-valley cycle is significant at specific working conditions. Moreover, since high ejection rate will produce high boiler load rate during the peak power period, and considering the high ratio value of peak and valley power prices, the ejector synergy unit shows more overall economic advantages. The converted generation income of the ejector synergy unit will firstly increase and then decrease with the increase of heating load.
    • Topic of Carbon Peak and Carbon Neutrality
  • Topic of Carbon Peak and Carbon Neutrality
    Study on Thermal Performance of Solar-assisted Gas Fired Decarburization Power Generation System with Oxygen-enriched Combustion
    JIANG Jin-tao, YE Xue-min, KONG Meng-di, SONG Rui-zhe, LI Chun-xi
    2023, 43(1): 65-73. https://doi.org/10.19805/j.cnki.jcspe.2023.01.009
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    Three schemes were proposed including a gas fired decarburization power generation system with oxygen-enriched combustion(scheme 1), an oxygen-enriched combustion gas fired decarburization power generation system integrated with waste heat recovery technology(scheme 2), and a solar-assisted gas fired decarburization power generation system with oxygen-enriched combustion(scheme 3). By studying the thermal economic indicators and economy of the three, scheme 3 is the optimal carbon capture approach, and the hourly thermal performance of which was further studied.Resultsshow that both scheme 2 and scheme 3 can improve the unit's thermal performance on the premise of increasing the cost of unit construction. Compared with scheme 2, scheme 3 can generate 91 047.06 MW more power per year and save fuel cost by 30.03 million yuan. In addition, with the increase of ambient temperature and solar direct normal irradiance, the power output of gas turbine generation in scheme 3 decreases, whereas the net power generation and net efficiency of the integrated system increase significantly.
  • Topic of Carbon Peak and Carbon Neutrality
    Research on State Prediction Method of Primary Air Fan Based on Improved LSSVM
    WANG Di, LI Zhi, WANG Yong, DENG Zhi-cheng, SUN Meng, FANG Chao, DING Gang, XIAO Bo-le
    2023, 43(1): 74-82. https://doi.org/10.19805/j.cnki.jcspe.2023.01.010
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    To meet the goal of "carbon peaking and carbon neutrality", focusing on the characteristics of complex working conditions and multivariable strong coupling of primary air fan, a primary air fan state prediction model based on least squares support vector machine(LSSVM) using improved longicorn whisker search algorithm(IBAS) optimization was proposed. Firstly, the original feature system was built in multiple dimensions according to the concept of "system + component", then the Pearson correlation coefficient was used to reduce the dimension of all dimensions' data. After that, IBAS was used to optimize the super parameters in LSSVM model, thus a complete primary air fan state prediction model was established. Finally, the measured data of primary air fan in a domestic power plant were used for example analysis.Resultsshow that the proposed method has specific advantages in accuracy and convergence speed, and the mean absolute percentage error is 2.53%, which is lower than other conventional models. The proposed method can meet the practical engineering needs of fan state prediction.
  • Topic of Carbon Peak and Carbon Neutrality
    Effect of Blade Trailing Edge Deflection on Performance of a Lift-type Vertical Axis Hydraulic Turbine
    LI Kai-di, ZHOU Dong-hai, SUN Xiao-jing
    2023, 43(1): 83-91,101. https://doi.org/10.19805/j.cnki.jcspe.2023.01.011
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    To improve the energy extraction efficiency of the traditional lift-type vertical axis hydraulic turbine(VAHT), the blade with a deformable trailing edge was utilized. The two-dimensional unsteady state numerical simulation was conducted to study the hydrodynamic performance of the VAHT using combined overset mesh and dynamic mesh in the CFD method. Two control strategies of deformable trailing edge, namely, constant trailing edge deflection to pressure surface(OSO) and continuous trailing edge deflection at constant angular speed(CD), were proposed. The perspective effects of the deflection length and deflection angle on the hydrodynamic performance of the VAHT were analyzed.Resultsshow that at a low leaf tip speed ratio, the strategy of OSO performs more effective. When the leaf tip speed ratio is 1.00, the combination of the deflection angle of 15° and the deflection length of 0.1 times chord length has achieved the best effect on the hydrodynamic performance of the turbine. Average energy extraction efficiency can be improved up to approximately 17.1%. However, the CD strategy effectively improves the average energy extraction efficiency at high and medium leaf tip speed ratios. Average energy extraction efficiency can be improved up to about 15.39%. In practice, these two control strategies could be combined and applied smartly, which will allow the VAHT to maintain a superior performance for energy harvesting under a wide range of operating conditions and achieve further engineering application value and potential.
  • Topic of Carbon Peak and Carbon Neutrality
    Research on Primary Frequency Regulation Control Strategy of High-penetration Offshore Floating Wind Farm
    SONG Zi-qiu, YU Zhao-guo, HU Yang, LIU Ji-zhen
    2023, 43(1): 92-101. https://doi.org/10.19805/j.cnki.jcspe.2023.01.012
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    To mitigate the intensification of frequency fluctuations in the power system caused by the grid connection of high-penetration floating wind farms, a primary frequency regulation model for a hybrid power system was established and the scheme of a coordinated primary frequency regulation control strategy according to its battery energy storage was produced. Numerical simulation was carried out for a region with 1 000 MW load reference, where installed a hundred of 5 MW floating wind turbines, and each turbine was equipped with a 1 500 kW×60 s battery energy storage system. The frequency response of the hybrid power system under the rotor kinetic energy joint overspeed load shedding(primary frequency regulation strategy) and the battery energy storage participation in the primary frequency regulation strategy was analyzed and compared.Resultsshow that under load step change and random change scenarios, the battery energy storage participation in primary frequency regulation will reduce power system frequency deviation and steady-state error, speed up frequency regulation response, and balance the output power of floating wind turbines, which can effectively improve the stability and economy of wind turbine operation, and further improve the frequency regulation performance of the power system.
  • Topic of Carbon Peak and Carbon Neutrality
    Optimization Analysis of CO2 Liquefaction Purification Process Based on Oxygen Enriched Combustion
    JIANG Rong, GAN Shuang, LI Xiao-shan, NI Hong-wei, LAI Yong-jie, LI Liang
    2023, 43(1): 102-108. https://doi.org/10.19805/j.cnki.jcspe.2023.01.013
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    Based on the S/N/Hg integrated flue gas compression purification process, the CO2 flue gas liquefaction purification process of typical oxygen enriched combustion was analyzed and a new process was proposed. By constructing the CO2 liquefaction purification system model, the flow of related substances and energy of the new process under various operating conditions was simulated, and the process parameters were optimized based on the exergy analysis.Resultsshow that when CO2 volume fraction in the purified flue gas is 76.6% and the pressure is 3 MPa, 99.99% CO2 liquid product can be obtained, and the CO2 recovery rate can reach 90%, the minimum energy consumption of the compression liquefaction purification system is 158(kW·h)/t.
  • Topic of Carbon Peak and Carbon Neutrality
    Modeling and Analysis of SOFC-GT System Based on Ammonia Decomposition
    MA Zhuang, QIN Jiang, LI Cheng-jie, WANG Cong, WANG Zi-xuan
    2023, 43(1): 109-116. https://doi.org/10.19805/j.cnki.jcspe.2023.01.014
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    In order to achieve the goal of low carbon emission in the cogeneration system, a fuel cell gas turbine hybrid power system with ammonia as the working fluid was proposed. By establishing a model of hybrid power system, the performance analysis and exergy analysis of the system were carried out, and the efficiency of the system was compared with that of a hybrid system with LNG as fuel.Resultsshow that the efficiency of the system can reach 72% within the optional range of fuel utilization and air excess coefficient, and the system has high exergy efficiency at the design point. The exergy loss mainly occurs at the fuel cell and air heat exchanger. And the efficiency of this system is higher than that of the LNG-fueled hybrid system at the same fuel flow rate.