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    Power Equipment and System
  • Power Equipment and System
    Simulation Study on Dynamic Characteristics of Water-cooled Wall of a 660 MW Supercritical Once-through Boiler
    WANG Chao, WANG Yankai, CHEN Xiangru, SUN Xingye, LIU Kairui, WANG Limin, CHE Defu
    2024, 44(7): 1001-1009. https://doi.org/10.19805/j.cnki.jcspe.2024.230297
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    In order to study the dynamic characteristics of boiler water-cooled wall, the water-cooled wall was divided into different modules, and the thermal deviation in height direction and circumferential direction was considered. The dynamic simulation model of the water-cooled wall of a 660 MW supercritical boiler was established. The wall temperature distribution of different walls in the water-cooled wall under the change of heat load was studied. When the different boundary conditions underwent step change, the response characteristics of the water-cooled wall were compared. The hydrodynamic and wall-temperature characteristics of the boiler water-cooled wall under load-variation conditions were studied. Results show that the change of the heat load of the rear wall only affects the wall temperature of the rear water-cooled wall and the slag tube. When the heat load of the rear wall rises to 1.5 times of the boiler maximum continuous rating (BMCR), the overtemperature phenomenon occurs at the slag tube. When the heat load, inlet feedwater flow rate and temperature undergo step change by -10%, the steam temperature at the separator outlet is changed by -7.97 K, +11.57 K and -19.97 K, respectively. The change of inlet feedwater temperature has the greatest influence on the steam temperature. Under the load lifting condition, the steam temperature first rises and then decreases. Under the load decreasing condition, the steam temperature first decreases and then rises.
  • Power Equipment and System
    Study on Dynamics of Fe Sedimentation in Transcritical Region of Supercritical Units
    XIAO Zhuonan, BIAN Bo, YANG Jie, LI Ke
    2024, 44(7): 1010-1018. https://doi.org/10.19805/j.cnki.jcspe.2024.230303
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    In order to obtain the dynamics of the deposition distribution of Fe particles in the transcritical region in the heating surface of the boiler of the supercritical unit, a two-dimensional model of the horizontal circular tube was established. The distribution of particle deposition was studied by changing the inlet temperature, inlet flow rate, wall heating power, particle force and particle diameter. Results show that particle size is the main factor affecting the kinetic process of particle deposition. For particles with a particle size greater than 1.0 μm, the forces that inhibit particle deposition are Saffman lift force, thermophoresis force and Brownian force. While the particle size is less than 1.0 μm, the forces that inhibit the particle deposition are thermophoresis force, Saffman lift force and Brownian force in descending order. When the particle size is 2.0 μm, it has the best deposition effect in the transcritical region, and with the increase of inlet flow velocity, the peak concentration of particle deposition gradually decreases, and the deposition position moves to the outlet of the pipe. With the increase of wall heating power, the total amount of 8.0 μm particles deposited won't change much.
  • Power Equipment and System
    Numerical Study of Combustion Characteristics of Low-calorific Value Gas Cyclone Burner
    QIAN Yejian, GONG Haoqi, MENG Shun, ZHANG Yu, GE Xinbin, LIU Bo
    2024, 44(7): 1019-1025. https://doi.org/10.19805/j.cnki.jcspe.2024.230294
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    In order to solve the problems of large output, low calorific value, difficult ignition and poor flame stability of low calorific value gas, a low-calorific value gas burner was designed based on the idea of staged combustion. A stable flame with rich combustion was formed in the center of the gas burner, and a swirl combustion flame was generated at the periphery, and a stable combustion flaring was designed at the outlet of the burner to achieve stable combustion of a single burner with low calorific value. The numerical calculation method was used to establish the calculation model of the burner. The effects of preheating temperature on the combustion characteristics and pollutant emission characteristics of low-calorific value gas burners were studied. And the velocity field, temperature field and NO emission during air preheating and low calorific value gas preheating were analyzed. Results show that with the increase of preheating temperature, the maximum reflux velocity increases, and the volume fraction of NO at the furnace outlet increases gradually. The effect of gas preheating with low calorific value on combustion is stronger than that of air preheating.
  • Power Equipment and System
    Process Simulation of In-situ Coal Gasification Chemical Looping Combustion Power Generation System
    WANG Xiaoyu, ZHAO Haibo
    2024, 44(7): 1026-1032. https://doi.org/10.19805/j.cnki.jcspe.2024.230346
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    A 600 MW in-situ coal gasification chemical looping combustion (iG-CLC) power generation system using Fe2O3/FeO as oxygen carrier was constructed by Aspen Plus software. Based on the simulation results of the system, the energy, exergy and exergy cost were analyzed respectively. Results show that the net thermal efficiency of iG-CLC power generation system is 35.38%. The component with the maximum internal exergy loss in the system is the air reactor, which accounts for 28.39% of the total exergy loss of iG-CLC subsystem components. Total internal exergy loss of the water vapor system is relatively small in the entire system, and is only 14% of the chemical looping combustion subsystem. The maximum unit exergy cost is 3.88 for air preheater in the iG-CLC power generation system, while the unit exergy costs of reheater, economizer and superheater are also larger.
  • Power Equipment and System
    Dynamic Simulation and Experimental Study of a Dual-rotor Inter-shaft Bearing System
    XIANG Ling, CHEN Kaile, LI Linchun, BING Hankun, HU Aijun
    2024, 44(7): 1033-1041. https://doi.org/10.19805/j.cnki.jcspe.2024.230310
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    In terms of the complex dynamic characteristics and mass imbalance phenomenon of a dual-rotor system, a dynamic model of the internal and external dual-rotor system was established. Its vibration characteristics were analyzed through axis trajectory diagram, time-domain diagram, spectrum diagram, Poincaré cross-section diagram and bifurcation diagram, and a dual-rotor experimental platform was built to conduct the acceleration and imbalance experiments and verify the correctness of theoretical research and computer simulation. Results show that during the acceleration process of the dual-rotor, there will be two sudden increases in amplitude, and the two main resonances are caused by the internal and external rotor speeds reaching the natural frequency of the system respectively. The dual-rotor system exhibits different vibration characteristics at different speeds. Increasing the imbalance of the internal rotor not only affects the vibration response of the internal rotor system, but also affects the vibration response of the external rotor system, and the impact on the former is more significant.
  • Power Equipment and System
    Optimization on Main Steam Pressure of a Steam Turbine Under Low Loads Based on IGWO-SVM
    WU Ruikang, LIU Di, ZHENG Jianping, TONG Jialin, YE Xuemin
    2024, 44(7): 1042-1050. https://doi.org/10.19805/j.cnki.jcspe.2024.230345
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    To improve the operating efficiency of steam turbine under low loads, it is necessary to optimize the main steam pressure. A heat rate prediction model was established by support vector machine (SVM) algorithm based on actual operating data of a unit. The improved grey wolf optimization (IGWO) algorithm was used to optimize the hyperparameters of the SVM model. The IGWO algorithm was used to optimize the feasible pressure range under low loads, and the optimized steam turbine sliding pressure curve was obtained and verified by a practical example. Results show that, the heat rate prediction model optimized using the IGWO algorithm can accurately predict the heat rate under low loads. After optimization, the heat rate of the unit is decreased under low loads, especially when the load is 223.83 MW, the heat rate is decreased by 505.96 kJ/(kW·h), presenting the largest reduction. The optimization scheme proposed can effectively improve the thermal economy of steam turbine under low loads.
    • New Energy Resources and Energy Storage
  • New Energy Resources and Energy Storage
    Intelligent Equivalent Modelling and Yaw Optimization Control of a Wind Farm Considering Wake Effects
    CAI Wei, HU Yang, LIU Jizhen
    2024, 44(7): 1051-1059. https://doi.org/10.19805/j.cnki.jcspe.2024.230370
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    The interference of wake in a large-scale wind farm decreases its overall power output. It is therefore necessary to establish an equivalent model of the wind farm and optimize its wake distribution to increase the overall power. The authors presented a novel yaw optimization framework for wind farms, including a radial basis function neural network algorithm improved by parameter supervised learning and regularization techniques, and an intelligent equivalent model for the power conversion of the wind farm targeting multi-degree-of-freedom yaw control. An optimization problem maximizing the power output of the wind farm with the yaw angles as decision variables was defined based on the present model. An enhanced elitist multiple population genetic algorithm was proposed and used to solve the optimization problem, and the optimum yaw angles of each wind turbines minimizing the wake interference were obtained. Numerical simulations were carried out to validate the equivalent models using an actual wind farm layout and realistic wind conditions. The results show good accordance between the present intelligent equivalent model and the actual characteristics of the wind farm. Under specific wind conditions, yaw optimization control leads to a power increase of 718.79 kW for the wind farm. For continuous wind conditions, the proposed optimization control method shows significant improvement under different wind conditions, resulting in an average power increase of 1 208 kW for the wind farm. The superiority of the proposed novel yaw optimization framework in enhancing the overall power output of wind farms has been validated.
  • New Energy Resources and Energy Storage
    Study on Dynamic Response of Wind Turbine Scour Effect Under Extreme Sea Conditions
    SHI Haodong, YAN Yangtian, YUE Minnan, LI Chun, NIU Kailun
    2024, 44(7): 1060-1067. https://doi.org/10.19805/j.cnki.jcspe.2024.230293
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    A shell element model considering soil-structure coupling effect was established to analyze the dynamic response of offshore wind turbine scour effect under different sea conditions based on finite element method. Results show that the peak displacement of the tower top and the top of the pile foundation increase under normal and extreme sea conditions when large scour occurs, and the peak displacement of the top of the pile foundation increases more. With the increase of scour depth, the horizontal displacement of the tower increases first and then decreases. The horizontal displacement of the pile foundation continues to increase with the increase of scour depth. The maximum acceleration position of the pile foundation occurs at the top of the pile foundation for different scour depths, and the maximum stress value of the tower occurs at the bottom of the tower. Compared with conventional sea conditions, the wind turbine in extreme sea conditions has been in unstable state after startup. The maximum acceleration is located in the middle and upper part of the pile foundation and continues to increase with the increase of scour depth. The peak stress of the pile foundation is transferred from the top of the pile foundation to the middle part.
  • New Energy Resources and Energy Storage
    Research on Load Reduction Characteristics and Mechanism Analysis Based on Synergy Between Pitch and Flap
    BAI Dongxiao, WANG Bing, LI Yinsheng, WANG Wancheng
    2024, 44(7): 1068-1074. https://doi.org/10.19805/j.cnki.jcspe.2024.230343
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    The effects of trailing flap length, deflection angle and angle of attack on the load reduction characteristics of airfoil were studied, and the influence mechanism was analyzed. Results show that the cooperative control of the pitch and the trailing flap can effectively realize the load reduction in the swing direction. The larger the length of the trailing flap, the smaller the trailing edge deflection angle. The farther away from the critical value of the angle of attack, the better the load reduction performance. The increase of the deflection angle will lead to the forward movement of the critical angle of attack. The tail edge control is preferred under the positive deflection angle and the large angle of attack, and the pitch control is preferred in other cases. The load reduction characteristics are closely related to the fluid distribution of the airfoil and wing slots, and the smaller the pressure difference, the better the load reduction performance.
  • New Energy Resources and Energy Storage
    Optimal Configuration of Solar Coupled Ground Source Heat Pump System Based on PSO-MSVR
    CHENG Junyan, LI Peng, ZHU Zishang, CUI Yu, ZHAO Wensheng
    2024, 44(7): 1075-1083. https://doi.org/10.19805/j.cnki.jcspe.2024.230323
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    Taking office building in Shenyang region as an example, a solar coupled ground source heat pump system (SGSHPS) model with different operation modes was established based on TRNSYS platform to optimize the configuration of SGSHPS. The soil temperature imbalance ratios and total energy consumption of the system after operation for 30 years in different modes were compared and analyzed. Using the parallel transition season thermal storage mode as the research object, different sets of solar collector systems and buried tube heat exchanger combination methods were simulated. Under the premise of stable system operation, the configuration of the solar collector area and the number of buried tube heat exchanger boreholes were optimized for minimum dynamic annual cost value. PSO-MSVR algorithm was introduced. PSO algorithm was used to generate the MSVR model parameters, as well as to find the optimal values. Results show that compared with the configuration method determined by the traditional heat balance method, the system energy consumption after operation for 30 years reduces by 379 522 kW for the optimized configuration method, which means energy saving of 11.2%. The annual cost reduces by 61 863 yuan, while the soil temperature only increases by 0.73 K. For different solar collector and buried tube heat exchanger costs, the annual costs after optimization reduce by different degrees compared with before optimization, and the soil temperature has not been greatly shifted.
  • New Energy Resources and Energy Storage
    Numerical Simulation Study on Collaborative Disposal of Agricultural and Forestry Wastes by Fluidized Bed Boilers
    LIN Guoqiang, YAN Deya, ZHANG Tao, LIU Deyu, CHENG Zhenyu, LI Huiyanchen, WANG Pengqian, WANG Chang'an
    2024, 44(7): 1084-1092. https://doi.org/10.19805/j.cnki.jcspe.2024.230332
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    Numerical simulation of agricultural and forestry waste blended firing in a 75 t/h circulating fluidized bed boiler was conducted. The correctness and reliability of the simulation model were verified by the experimental data through comparison. The effects of blending conditions and boiler operating parameters on combustion characteristics in the furnace, pollutant emission and furnace wear were analyzed thoroughly. The results show that the combustion characteristics are improved by low blending ratio of the agricultural-forestry waste and high primary air ratio. While high blending ratio of the agricultural-forestry waste will reduce pollutant emission.
  • New Energy Resources and Energy Storage
    Optimization of Pt-based Bimetallic Structured Catalysts for Hydrogen Production from Methane and Methanol Dual Fuel Reforming
    ZHAO Yanchun, REN Yanlun, WANG Kun, LU Xiaolin, ZHANG Li, LAN Jian
    2024, 44(7): 1093-1100. https://doi.org/10.19805/j.cnki.jcspe.2024.230309
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    Using FeCrAl with honeycomb structure as the substrate, Pt-Rh(Cu)/Ce0.75Zr0.25O2/Al2O3 bimetallic structured catalyst was prepared, the morphology and hydrogen production performance of the catalyst were analyzed. The experimental device was built to evaluate the hydrogen production performance of the catalyst. Results show that the surface morphology of the prepared Pt-Rh/Ce0.75Zr0.25O2/Al2O3/FeCrAl is uniform, without obvious color difference and plugging holes. There are numerous surface pores on the catalyst surface, showing a cobweb porous form, which is easy to realize catalyst loading. Thus, the catalyst has higher gas adsorption and reaction space. When the molar ratio of Pt to Cu is 1∶15, the highest activity in the fresh state of the prepared Pt-based catalysts can be obtained, which has a conversion rate of more than 75% for methanol and methane steam reforming reaction, and the hydrogen concentration is high. Compared with Pt-Cu catalyst, Pt-Rh catalyst has higher stability and lower agglomeration of active components. The prepared bimetallic catalyst can be applied to both methane and methanol dual fuels, and has good hydrogen selectivity.
  • New Energy Resources and Energy Storage
    Economic Configuration of Flywheel Collaborative Battery Hybrid Energy Storage System for Smoothing Wind Power Fluctuations
    TENG Wei, XU Qingxiang, WANG Yajun, QIN Run, WU Xin, LIU Yibing
    2024, 44(7): 1101-1108. https://doi.org/10.19805/j.cnki.jcspe.2024.230324
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    In response to the fluctuation of active power in wind farms, a power smoothing algorithm based on wavelet packet decomposition was adopted to obtain low-frequency signal components that meet grid connection requirements and high-frequency hybrid energy storage system reference power. Low pass filtering, frequency division and signal smoothing denoising methods were used to obtain reference signals for flywheel energy storage and battery energy storage. Simultaneously, considering the impact of discharge depth and cycle count on the lifespan of the battery energy storage system, a hybrid energy storage system's full life cycle economy model was constructed within the planned years. The optimal configuration of the hybrid energy storage capacity was obtained through multi-tracker optimization algorithm (MTOA). Finally, based on actual power data from the wind farm, simulation analysis was conducted to verify the effectiveness and economic of hybrid energy storage system (HESS) in power smoothing. Results show that HESS can not only ensure that the active power fluctuation of the wind farm meets the grid connection requirements, but also fully utilize the characteristics of different energy storage forms to reduce the operating costs of the system.
    • Digitalization and Intelligentization
  • Digitalization and Intelligentization
    Power Regulation Strategy of Wind-Solar-Hydrogen Coupling System Based on Parameter Adaptive Stochastic Model Predictive Control
    HUANG Yu, ZHOU Xinpeng, GUO Haode, WANG Dongfeng, XIE Jiale
    2024, 44(7): 1109-1117. https://doi.org/10.19805/j.cnki.jcspe.2024.230124
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    A parameter adaptive stochastic model prediction control(PASMPC) power regulation strategy was proposed based on scenario analysis method, aiming at the impact of uncertainty on the power balance of the wind-solar-hydrogen coupling system on both the source and load sides. A linear discrete state-space model was established to describe its dynamic characteristics, based on the energy supply architecture of the wind-solar-hydrogen coupling system. Then, the scenario analysis method was used to describe the uncertainty of the system as input for the PASMPC.Under the framework of the designed PASMPC, the goal of extending the life cycle of the system equipment was taken into consideration for optimization. To compensate for the defects of fixed time domain prediction and control time domain instochastic model prediction control during optimization process, a parameter adaptive method was proposed to obtain better optimization control effect. Results show that the PASMPC strategy improves the system power balance by 6.25 percentage compared with the stochastic model prediction control. Compared with the conventional model predictive control, the high-power operation of the system-controllable equipment is reduced by 60%, which verifies that the proposed strategy can effectively solve the uncertainty on both sides of the source and load of the wind-solar-hydrogen coupling system.
    • Green Energy and Low-carbon Technology
  • Green Energy and Low-carbon Technology
    Dynamic Prediction for SO2 Concentration in SD-WFGD System Based on Mechanism-Data Combined Model
    LI Ruilian, ZENG Deliang, ZHANG Guangming, XIE Yan, ZHU Yansong, ZHU Hongcheng
    2024, 44(7): 1118-1128. https://doi.org/10.19805/j.cnki.jcspe.2024.230355
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    In order to achieve the economic operation and ensure that the SO2 emission concentration of desulfurization system meets environmental requirements in a coal-fired unit, a combined dynamic prediction model was established for SO2 concentration at the outlet of the single-tower double-cycle wet fuel gas desulfurization (SD-WFGD) system. Firstly, the chemical reaction process of absorbing SO2 was analyzed, and the SO2 concentration mechanism models at the outlet of the absorption tower and absorber feed tank (AFT tower) were established respectively. Secondly, the historical data and mechanism deviation data were decomposed using variational mode decomposition (VMD) method, and the decomposed arrays with different frequencies were reconstructed. After which, models with different modal components were trained and obtained based on least square support vector machine (LSSVM) algorithm, while a data compensation model was established based on adaptive weight allocation strategy by the weighted stacking of LSSVM models with different modal components. Finally, a combined dynamic prediction model for SO2 concentration in the SD-WFGD system was obtained through the superposition of the outputs of dynamic compensation model and mechanism model. Results show that after the decomposition of historical data into different modes by VMD algorithm, the prediction accuracy of data model can be improved effectively with the reconstruction of data in different modes. Meanwhile, the model prediction ability can be improved with the combination of mechanism model and data model.
  • Green Energy and Low-carbon Technology
    Study of Release Characteristics of Arsenic and Distribution Pattern of Arsenic Species in Ash During Low-load Combustion of High-arsenic Anthracite Coal
    YUAN Xiao, XING Jiaying, WANG Zhen, WANG Chunbo
    2024, 44(7): 1129-1136. https://doi.org/10.19805/j.cnki.jcspe.2024.230349
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    Employing high-arsenic anthracite and employing a tubular furnace, the release of arsenic and the variation of arsenic speciation in ash under low-load coal combustion conditions was investigated. Results show that within the temperature range of 800-900 ℃, the release rate of arsenic from coal exhibits a significant peak with increasing temperature, while the proportion of As3+ in ash shows an upward trend. And the proportion of weak adsorbed arsenic in ash gradually increases within 800-900 ℃, which reaches its peak at 900 ℃. Within the range of 1 000-1 200 ℃, weak adsorbed arsenic in ash undergoes oxidation and decomposition, leading to an increase in the proportion of arsenate, prompting the transition of As3+ to As5+, and consequently, the proportion of As3+ decreases gradually. The increase of the volume fraction for O2 facilitates the oxidation process of As3+ in ash. Furthermore, with the extension of coal particle residence time in the furnace, the release rate of arsenic from coal synchronously varies with the proportion of As3+ in ash.
  • Green Energy and Low-carbon Technology
    Comparison of the Thermo-economic Analysis of Different Decarbonisation Mode for Coal-fired Power Plants Operating Under Wide Load Operation
    MA Yunteng, XU Cheng, LI Lincong, XIN Tuantuan
    2024, 44(7): 1137-1143. https://doi.org/10.19805/j.cnki.jcspe.2024.230331
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    Three different decarbonization operational modes for coal-fired power plant under various power outputs and CO2 capture rate constraints were proposed. A thermo-economic analysis was conducted on a typical 600 MW coal-fired power plant under these three decarbonization modes, so as to obtain the optimal decarbonization strategy for the power plant in varying scenarios of electricity prices, coal prices, and carbon taxes. Results show that constant power mode minimizes energy consumption penalties for the power plant, yet it fails to meet stringent CO2 capture requirements across all operating conditions. For the reduced power mode and constant power mode, when the grid electricity price falls below 0.371 yuan/(kW·h) or the coal price is below 682.45 yuan/t, the reduced power mode offers greater additional economic benefits. When electricity prices range is 0.371-0.407 yuan/(kW·h) or coal prices is between 682.45 and 758.94 yuan/t, the appropriate operating mode should be selected based on the unit's load. If the electricity price is higher than 0.407 yuan/(kW·h) or the coal price is below 682.45 yuan/t, and the unit load is below 93%, the constant power mode yields higher returns.
  • Green Energy and Low-carbon Technology
    Life-cycle Carbon Footprint Assessment and Techno-Economic Analysis of Hydrogen Production and Blending Integrated System
    QU Xiuyuan, YU Qianyue, ZHENG Na, WANG Hongjian, SUN Li
    2024, 44(7): 1144-1152. https://doi.org/10.19805/j.cnki.jcspe.2024.230305
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    By developing a simulation model of hydrogen production and blending integrated system, the life cycle inventory of multi-energy flow and material flow data was established to quantitatively evaluate technical economy and carbon reduction potential of the integrated system. Based on models of levelized cost and net present value of hydrogen-doped natural gas, influences of important technical parameters including energy efficiency and current density, and economic factors including wind power prices and raw material costs, on the economic evaluation index were analyzed. The tech-economic feasibility of the integrated system was evaluated. Furthermore, a whole life cycle carbon footprint evaluation model was employed to assess the carbon reduction potential. The study shows that the prices of raw materials and electricity are the primary factors influencing the levelized cost. A decrease of 0.10 yuan/(kW·h) in wind power transaction price can result in a reduction of 149 yuan/t in the levelized cost. The proposed new reconstruction and expansion project with an annual output of 15 700 t of green hydrogen and 502 800 t of natural gas yields a net carbon emission of 27 816 t, while the total CO2 emission from natural gas amounts to 1 334 175 t per year, considering its calorific value as hydrogen. The project is feasible in economic technology and environmental friendliness.