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    Power Equipment and System
  • Power Equipment and System
    Thermodynamic Performance Study on Coal-fired Power Plant Integrated with Molten Salt Thermal Energy Storage System
    YANG Haisheng, WU Ruitao, LI Lujiang, TANG Guangtong, MIAO Lin, LIU Ming
    2025, 45(5): 645-653. https://doi.org/10.19805/j.cnki.jcspe.2025.240141
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To enhance the energy efficiency of the thermal energy storage system using superheated steam to heat molten salt, a coal-fired unit system configuration integrating the three-tank molten salt thermal energy storage system was proposed. The flexibility improvement potential of coal-fired power plant and the thermodynamic performance of the integrated system were analyzed under typical charging and discharging conditions. Results show that under the condition of 30% THA for the charging process, the maximum output power of coal-fired power plant can be reduced by 81.60 MW, accounting for 12.36% of the rated load, due to the limitation of the minimum steam flow rate through the low-pressure turbine. Under the condition of 50% THA for the discharging process, the maximum output power of coal-fired power plant can be increased to 52.45 MW, accounting for 7.95% of the rated load. The equivalent round-trip efficiency of the integrated system is influenced by the discharging condition. The maximum equivalent round-trip efficiency is 75.35% at the discharging condition of 50% THA, while the minimum equivalent round-trip efficiency is achieved at 59.43% at the discharging condition of 100% THA.
  • Power Equipment and System
    Experimental Study on Effects of Near-wall Streamwise Vortex on the Film Cooling Performance of Multi-row Fan-shaped Holes
    WANG Jianan, CUI Xiaofeng, LIN Chixiang, DAI Ren
    2025, 45(5): 654-661. https://doi.org/10.19805/j.cnki.jcspe.2025.240177
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    A vortex generator was installed on a flat film experimental platform to generate streamwise vortices, and the effect of secondary flow in the blade end region on the film cooling effect of multi-row fan-shaped holes was studied. The adiabatic film cooling efficiencies of four row film holes were experimentally measured, and the influence of the film cooling efficiency of each row of holes was analyzed based on the Sellers formula. Results show that the air film coverage distorts along the motion path of the vortex due to the influence of the vortex direction, leading to a decrease in the cooling effect of the air film and the formation of hot spots at the core of the second row of vortices. The influence degree of vortices is related to the air film blowing ratio, and near wall vortices mainly reduce the air film cooling effect of the first two rows of holes. The cooling efficiency of the first row of holes significantly decreases, while the decrease value of the second row of holes is decreasing and the impact on the rear row of holes is gradually weakened. The air film after the third row of holes is basically not affected.
  • Power Equipment and System
    Simulation and Implementation of Performance and Decoupling Control for Centrifugal Compressors
    YANG Mingcheng, HAO Ning, LIU Chuanliang, ZHAO Feng, ZHANG Tianbo, LIU Jia
    2025, 45(5): 662-674. https://doi.org/10.19805/j.cnki.jcspe.2025.240086
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To meet the basic requirements of performance regulation for centrifugal compressors, the coupling effect between performance regulation and anti-surge control under different operation conditions of the compressor were deeply analyzed. A control strategy for decoupling the performance controller was proposed based on conditions such as the compressor's working point and load increase/decrease. Additionally, by adopting the quasi-nonlinear modeling method, the compressor system and control models were developed, which could be solved in real time on a unified platform. Model solving was conducted via a multidisciplinary simulation platform, yielding the compressor's dynamic characteristics under variable conditions and verifying the control effects of the performance control and decoupling strategy. Results show that the proposed method achieves performance control, realizing the design concept of prioritizing anti-surge valve closure during load increase and rotational speed reduction during load decrease, ensuring stable unit operation when the compressor runs under variable loads.
    • New Energy Resources and Energy Storage
  • New Energy Resources and Energy Storage
    Operating Characteristics of Axial Flow Compressors and Cycle Systems for Different Capacities of sCO2
    WANG Tianze, XU Jinliang, ZHENG Haonan
    2025, 45(5): 675-684. https://doi.org/10.19805/j.cnki.jcspe.2025.240117
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A compressor performance prediction model was proposed for certain sCO2 coal-fired cycle unit, and the compressor, turbine and boiler models were coupled with the cycle system. Results show that the characteristic sizes and capacity of the compressor follow the 0.5 power law. As the capacity and rated speed increase, the isentropic efficiency improves accordingly. Power consumption is reduced and efficiency is increased when the inlet parameters approach the critical point. When the inlet conditions are fixed, the isentropic efficiency shows a parabolic trend of first increasing and then decreasing with the rise of outlet pressure, with the peak corresponding to the optimal pressure ratio. When the shaft speed of the cycle unit is constant, the thermal efficiency shows a parabolic distribution with the increase of capacity, with the peak appearing at the 300 MW capacity point. If the shaft speed is optimized in coordination with the capacity, the thermal efficiency curve remains parabolic, but the peak shifts to the 600 MW capacity point, due to the weighing effects of turbine efficiency improvement and boiler pressure drop increase.
  • New Energy Resources and Energy Storage
    Experimental and Numerical Simulation Study on a Beam-down Concentrating Molten Salt Receiver
    XIE Wentao, GU Xinzhuang, DAI Yanjun, XU Da, LIN Meng, YU Bo, SONG Shixiong
    2025, 45(5): 685-692. https://doi.org/10.19805/j.cnki.jcspe.2025.240162
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    A T-shaped molten salt receiver was designed and modelled. A 3D numerical model of the reciver was established, coupling the boundary conditions of the beam-down concentrated solar radiation with molten salt flow, heat transfer, and solar energy absorption. The energy loss mechanisms of the receiver were revealed and the impacts of the molten salt's extinction coefficient, flow distribution, and filter mesh location on the internal temperature distribution of the receiver were analyzed via this approach. Results show that the outlet molten salt temperature reaches 560-570 ℃. The main energy losses are re-radiation loss, convection loss and optical reflection loss. The receiver with smaller extinction coefficient exhibits higher internal temperatures compared with receivers with larger extinction coefficient and shallow filter mesh, as the substantial heat absorbed by deep-layer molten salt cannot be rapidly discharged, leading to a heat accumulation inside the receiver.
  • New Energy Resources and Energy Storage
    Advances in Composite Phase Change Materials for Photothermal/Electrothermal Conversion and Storage
    XU Ao, LIAO Juan, LI Chuanchang
    2025, 45(5): 693-705. https://doi.org/10.19805/j.cnki.jcspe.2025.240152
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Phase change materials (PCM) are effective materials for thermal energy storage with a wide range of application prospects. However, their inherent low thermal and electrical conductivity greatly hinder their practical application in the field of thermal energy storage. By compositing PCM with different energy conversion materials, efficient mutual conversion among various forms of energy and thermal energy has been achieved. The composite PCM plays a key role in solar photothermal/electrothermal conversion and storage. In the field of photothermal conversion, the compositing of high thermal conductivity photothermal conversion materials with PCM has optimized the thermal conductivity and effectively enhanced the heat storage capacity, photothermal conversion efficiency, and solar energy utilization efficiency. In the field of electrothermal conversion, the preparation of electrothermal composite phase change materials by introducing high electrical conductivity supporting materials has not only improved the electrothermal conversion efficiency but also enriched the utilization methods of electrical energy. A detailed review of the latest research progress on photothermal and electrothermal conversion materials was provided, and the materials were classified. Aiming to offer new insights for the advancement of energy storage technology, the advantages and disadvantages of various types of materials were analyzed, the mechanisms for improving thermal energy conversion efficiency were revealed, and future development directions and challenges were prospected.
    • Digitalization and Intelligentization
  • Digitalization and Intelligentization
    Power Control Method for Floating Offshore Wind Turbines Based on Wave Interval Estimation and Prediction
    XU Yuhan, WU Zelong, SONG Ziqiu, WEI Le, FANG Fang
    2025, 45(5): 706-713. https://doi.org/10.19805/j.cnki.jcspe.2025.240741
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    Wave is a main contributor to the power fluctuations in floating offshore wind turbines (FOWTs), and therefore challenges the large-scale grid integration of FOWTs. To reduce the impact of waves on wind turbine power, a power control method for floating turbines based on wave interval estimation and prediction was proposed. Focusing on the rated power tracking control of the FOWT above the rated wind speed, a FOWT model with input time delay under large inertia and a wave disturbance model were established, a wave predictor based on wave interval estimation was designed, and then a composite time-delay control strategy was developed combining wave compensation and integral sliding mode control. The operation of a semi-submersible FOWT under the present control strategy was simulated using a FAST-Matlab/Simulink co-simulation environment and compared to the system response under traditional PI control. Results show that the proposed power control strategy can effectively compensate for the impact of wave disturbances on FOWTs, significantly reduce power output fluctuations, and provide a reference for the design of control systems for floating wind turbines.
  • Digitalization and Intelligentization
    Research on Early Fault Diagnosis Method of Rolling Bearing Based on RTH-FMD and 1.5-dimensional Spectrum
    TANG Guiji, ZHANG Long, XUE Gui, XU Zhenli, ZENG Pengfei, WANG Xiaolong
    2025, 45(5): 714-723. https://doi.org/10.19805/j.cnki.jcspe.2025.240113
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem of early fault diagnosis of rolling bearings, a fault diagnosis method of red-tailed hawk (RTH) algorithm optimization with feature mode decomposition (FMD) and 1.5-dimensional spectrum was studied. Firstly, through theoretical analysis, pulse energy factor index (PEFI) was designed and used as fitness function. Secondly, RTH algorithm combining with FMD was used to search the key parameters of the optimal decomposition in parallel. Then, the optimal signal component after decomposition was selected by PEFI, and the envelope demodulation was performed. Finally, the 1.5-dimensional spectrum of envelope signal was calculated, and the characteristic frequency information of bearing fault extracted was analyzed in the spectrum diagram to realize the accurate diagnosis of early weak bearing fault. The results of simulated fault experiments and engineering case analysis show that the proposed method can solve the problem of parameter self-adaptation, greatly reducing the impact of noise and other interfering components on diagnosis. It possesses good robustness and can effectively extract weak feature information from early bearing fault signals. It has important practical engineering reference value.
  • Digitalization and Intelligentization
    Research on Fault Warning of Coal Mill Based on Feature Selection and Multivariate Regression Prediction with BiLSTM
    LUO Yun, LI Zhanguo, FU Longxia, WANG Daoyi, ZHANG Xinzhong, LI Yaohua, CHENG Liang, JIANG Xia
    2025, 45(5): 724-732. https://doi.org/10.19805/j.cnki.jcspe.2025.240145
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To address the difficulty of fault diagnosis in thermal power equipment with multi-parameter coupling and gradual changes, a fault early warning method based on least absolute shrinkage and selection operator (LASSO) regression feature selection and bidirectional long-short term memory (BiLSTM) multivariate regression prediction was proposed. Taking a coal mill in a 1 000 MW power unit as the research subject, feature parameters such as mill current, outlet pressure, and inlet-outlet differential pressure were selected to represent blockage faults. LASSO regression was employed to select the feature variables, and a multivariate regression prediction model was established based on the BiLSTM algorithm. According to the variation mechanism of the feature parameters during mill blockage and the predicted values of the model, a mill blockage fault index was constructed. Finally, the warning threshold was determined using the kernel density estimation method, enabling mill blockage fault warnings. Actual data analysis shows that when the coal mill is operating normally, the average relative error of the BiLSTM multivariate regression prediction model is 1.13%. Compared with the traditional error back-propagation (BP) neural network and support vector regression (SVR) model, it has higher accuracy and the ability to predict the trend of parameter change. When the coal mill is operating abnormally, this method can detect operational abnormalities earlier than the multivariate state estimation technique (MSET) algorithm model, enabling early fault warning under variable operating conditions of the coal mill.
  • Digitalization and Intelligentization
    Research on Price Prediction of Electricity Market Based on Long-Short Term Memory Network
    SHAO Yunshu, ZHANG Lin, ZHOU Naikang, CHEN Xiaoli, WANG Fei
    2025, 45(5): 733-737. https://doi.org/10.19805/j.cnki.jcspe.2025.250019
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Considering the impact of multi-factor coupling in the power market on power price forecasting, a power market price forecasting model based on long-short term memory (LSTM) neural network was established. The historical new energy output, power transmission, power load and other factors affecting the power supply and demand relationship were set as the boundary factors of LSTM learning parameters, and data preprocessing was carried out. The model parameters of LSTM neural network, including the number of layers, iteration times and learning rate, were optimized to generate a training model for electricity price forecasting, which was then used to forecast the electricity price curves for trading days. The correctness of the proposed method was verified through example simulation, a prediction scenario for electricity trading in a spot market province was constructed, and the evaluation indicators of power price forecasting accuracy were introduced. The results indicate that this method provides a reference for research on day-ahead clearing price prediction and offers market participants in the electricity market effective bidding strategies to achieve substantial marketing revenue.
    • Green Energy and Low-carbon Technology
  • Green Energy and Low-carbon Technology
    Simulation Study on CO2 Capture System of Calcium Cycle Flue Gas of a 1 000 MW Coal-fired Power Generation Unit
    WANG Changqing, TAN Yuyao, XU Ruichang, ZHOU Zijian, LIU Wenqiang, HU Yong, XU Minghou
    2025, 45(5): 738-746. https://doi.org/10.19805/j.cnki.jcspe.2025.240368
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    Based on Aspen Plus software, a carbon capture system model of high-temperature Ca-based adsorbent was established, and simulation study was carried out for CO2 capture process of flue gas in a 1 000 MW coal-fired unit. Aiming at the problems of high energy consumption and pollutants emission in energy supply of oxygen-enriched coal combustion in calciner, external electric heating energy supply was proposed to provide heat for calciner. The changes in key performance parameters after flue gas entering the carbon capture system were investigated in detail. On this basis, the conservation of energy and mass, as well as the effects of different operating parameters on system performance were analyzed. Results show that after the carbon capture system is added in the 1 000 MW coal-fired generating unit, the thermal efficiency of electricity generation will decrease by 26.11%. When the temperature of the carbonization furnace is maintained at 645 ℃, CO2 capture efficiency will be 92.13%. CaCO3 will be decomposed more thoroughly when the calcination furnace temperature is set at 900 ℃. The increase of temperature in carbonation furnace will reduce energy consumption of calcination and improve thermal efficiency of power generation, while the increase of calcination temperature will increase energy consumption and reduce thermal efficiency of power generation. The increase in calcium-carbon molar ratio leads to the increase of solid circulation in the calcium-based carbon capture system, while average carbon conversion of calcium-based adsorbents shows negative correlation.
  • Green Energy and Low-carbon Technology
    Study on Synergistic Generation Law of NOx and CO2 in Biomass Gas-coupled Gas Heating Furnace
    ZHONG Buyi, YAN Zhenrong, ZHU Shuixing, YANG Yinwu, TENG Lan, LIAO Feilong
    2025, 45(5): 747-754. https://doi.org/10.19805/j.cnki.jcspe.2025.240081
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    Taking a certain gas-fired heater as the research object, synergistic rules of NOx and CO2 production under different proportions of biomass gas co-firing were studied. Results show that compared with pure gas combustion, co-firing biomass gas can reduce furnace flame center, peak temperature of furnace flue gas and outlet flue gas temperature of the convection chamber. When the co-firing ratio is 10%, the volume fraction of carbon decreases by 25.3%, and the volume fraction of NOx at the outlet is reduced by 67.1%. When the co-firing ratio exceeds 10%, the outlet NOx production decreases slowly. When the co-firing ratio is 5%-10%, the CO2 and NOx production shows a positive synergistic trend, while when the co-firing ratio is within the range of 15% to 30%, the generation amounts of CO2 and NOx show a negative synergistic trend. Therefore, to synergistically reduce the generation amounts of CO2 and NOx, the optimal co-firing ratio is 10%. At this ratio, the furnace outlet volume fraction of CO2 is the lowest(2.30%), and the volume fraction of NOx emissions is 49.8×10-6.
  • Green Energy and Low-carbon Technology
    Ammonia-based Flue Gas Decarbonization for NH4HCO3 Production System Based on a Combination of Photovoltaic Power Generation and Green Hydrogen and Green Ammonia Production
    WANG Sen, WANG Siyao, YUAN Xin, LI Tianxin, PAN Peiyuan
    2025, 45(5): 755-764. https://doi.org/10.19805/j.cnki.jcspe.2025.230770
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problems of the high energy consumption of CO2 regeneration and the superior difficulty of CO2 utilization in the flue gas decarbonization system with traditional monoethanolamine (MEA) method, a novel ammonia decarbonization system for producing NH4HCO3 was proposed based on the water photovoltaic electrolysis for hydrogen production and Haber-Bosch ammonia synthesis process.This system utilized photovoltaic electrolysis of water to produce green hydrogen, which was further synthesized with N2 to produce green ammonia (NH3). The NH3, in solution form, reacted with CO2 in flue gas in an absorption tower to generate NH4HCO3. Simultaneously, the rich liquor (containing NH4HCO3) was cooled and separated to produce NH4HCO3, achieving the co-production of electricity, heat, and NH4HCO3 with low carbon emissions, and avoiding the challenges associated with large-scale storage and utilization of CO2. Based on a 300 MW coal-fired unit, a simulation model of the system was established in Aspen Plus V11 software. Calculation and analysis results indicate that the system can remove 1.546 8 million tonnes of CO2 annually from flue gas (with a decarbonization rate of 85%), and produce 2.792 million tonnes of NH4HCO3, 1.034 2 million tonnes of by-product O2, and 4.731 4 million tonnes of hot water annually. It requires the configuration of a photovoltaic power unit with an installed capacity of 2 594 MW and an ammonia production system with an annual output of 620 500 tonnes. The equivalent cost of carbon dioxide removal is 233.96 yuan per tonne.
  • Green Energy and Low-carbon Technology
    Migration and Transformation Characteristics of Mercury During Desulfurization Wastewater Evaporation
    SUN Zongkang, CHEN Heng, GU Liyan, ZHAN Lingxiao, YANG Linjun
    2025, 45(5): 765-770. https://doi.org/10.19805/j.cnki.jcspe.2025.240055
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    In response to the issue of mercury re-release associated with the bypass flue gas evaporation technology for desulfurization wastewater, the distribution and release mechanism of mercury in the evaporation process of desulfurization wastewater were investigated, and the effects of flue gas temperature and wastewater components (Cl-, SO32-) were examined. Results show that 94.1% of mercury in the wastewater can be released into the gas phase under typical working conditions, and the release process can be divided into three stages: gaseous Hg0 is the main source of mercury release during the initial evaporation process; subsequently, due to the hydrolysis of chloride, a chlorine-oxidizing atmosphere is generated, which induces the uniform oxidation of Hg0; and at the end of the wastewater evaporation, a small amount of Hg is released in the pyrolysis of HgS and HgO. In addition, the higher the evaporation temperature of the wastewater, the worse the stability of mercury. The concentrations of SO32- and Cl-in the wastewater have a large influence on the release proportional of gaseous Hg0 and Hg2+.
  • Green Energy and Low-carbon Technology
    Occurrence Mode and Thermal Stability of Mercury in Middlings
    GAO Libing, REN Bingru, GUO Shaoqing, LI Hongyan
    2025, 45(5): 771-776. https://doi.org/10.19805/j.cnki.jcspe.2025.240061
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    The occurrence modes of mercury in middlings from different origins were studied by using sequential chemical extraction, and the thermal stability of various occurrence forms was investigated by combining temperature programmed decomposition-atomic fluorescence spectrometry (TPD-AFS) technique. Results show that mercury in middlings mainly exists in the forms of exchangeable Hg, carbonate and oxide surface bound Hg, organic bound Hg, sulfide bound Hg, silicate bound Hg and residual Hg. In middlings, the dominant form of mercury is the sulfide bound Hg, accounting for 60.67%-62.93% of the total mercury content, there are two release peaks, mainly released at 150-400 ℃, and less at 400-600 ℃. The content of residual Hg accounts for 14.63% to 25.31%, mainly released within the temperature range of 150-300 ℃. The content of organic bound Hg accounts for 3.98% to 7.99%, mainly released within the temperature range of 400-600 ℃. The content of silicate bound state Hg ranges from 2.18% to 3.34%, and it is released after 600 ℃. The content in the exchangeable state Hg ranges from 1.01% to 3.20%, and it shows no obvious release during pyrolysis. The content in the surface bound state Hg of carbonate and oxide is the least, ranging from 0.46% to 1.33%, and it is mainly released within the temperature range of 180-340 ℃.
    • Integrated Energy System
  • Integrated Energy System
    Multidisciplinary Multi-E Evaluation Analysis Method for CHP System
    CHEN Jianhong, ZHANG Kaiji, CHEN Qingle, YANG Shuai, FANG Wei
    2025, 45(5): 777-784. https://doi.org/10.19805/j.cnki.jcspe.2025.240072
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the operation mechanism of combined heat and power (CHP) system, focus product concept was introduced by combining multidisciplinary concerns with heat and power products generated by the system, and the focus products were aligned with E modules. By leveraging the relationship between product quality analysis and output evaluation, a comprehensive multi-E evaluation system was constructed, and a holistic multi-E analytical theoretical system was objectively established. Using the concepts of universal set and subset from set theory, evaluation indicators were treated as elements of a set, therefore the process of E module determination was transformed into the filtration process from the universal set to its subsets. Taking a typical CHP system as the example, combined with the multi-E theoretical system, the subset filtration processes of CHP system under various optimization objectives were analyzed. Results show that the constructed multi-E evaluation analysis method can provide valuable reference for similar research.
  • Integrated Energy System
    Wide Load Flexible Control Strategy of Supercritical Combined Heat and Power Unit Based on Deep Reinforcement Learning and Data-driven Approach
    ZHU Keyan, ZHANG Guangming, WANG Qinghua, WANG Wei, NIU Yuguang, LIU Jizhen
    2025, 45(5): 785-795. https://doi.org/10.19805/j.cnki.jcspe.2025.240114
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    To meet the demand for flexible regulation performance of traditional thermal power units, a data-driven nonlinear environmental modeling method for supercritical combined heat and power (S-CHP) and a reinforcement learning control method based on double-delay deep deterministic strategy gradient (TD3) were proposed. Firstly, a data-driven nonlinear model environment was established based on the deep learning algorithm of multi-layer perceptron (MLP) and the dynamic characteristics of the S-CHP unit. Furthermore, based on deep reinforcement learning algorithms, an actor critic strategy value network and S-CHP specific state values and reward functions were designed to conform the dynamic characteristics of the S-CHP unit. A flexible control strategy of TD3 was proposed to achieve the control objectives of rapid response, ensuring heating supply and stable operation. Results show that compared with single-layer networks, the MLP model reduces the root mean square error by 51.7% at the rated power of 52%-93%. Compared with the traditional coordinated control method, the TD3 control strategy has better tracking effect and higher response rate.
  • Integrated Energy System
    Research on Condition Matching and Economic Efficiency Diagnosis Method for Thermal Power Unit Based on Just-in-time Learning
    LIU Wei, REN Shaojun, SI Fengqi
    2025, 45(5): 796-804. https://doi.org/10.19805/j.cnki.jcspe.2025.240170
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    Most existing data-driven energy optimization and energy-saving diagnostic methods were based on offline global models for analysis. Complex and variable states of the units during actual operation could degrade the performance of these models. Regarding this issue, a method for economic efficiency diagnosis of the unit was proposed based on just-in-time learning (JITL) and condition matching. This method involved preprocessing historical operational data of the unit, selecting boundary parameters and relevant parameters related to the target parameter. The conditions were divided into different cells under various boundaries through grid partitioning and the samples with optimal performance were selected as the benchmark condition sample set, and the target condition database was established. Condition matching was conducted based on this database. If the matching was successful, the optimal performance value under the corresponding boundary was selected as the parameter benchmark. Otherwise, a JITL approach was employed, which extracted similar condition samples through similarity measurement, and established a local online model to output the predicted value as the benchmark for performance evaluation and control adjustment. Results show that benchmark values of plant electricity consumption rate for different operating conditions and optimization strategies for desulfurization electricity consumption rate can be obtained based on the proposed method, providing reliable guidance for unit operation optimization.