In order to study the effect of molten salt thermal storage schemes on peak shaving capacity and economy of double reheat condensing units, by taking a 660 MW double reheat condensing unit as an example, seven bypass thermal storage schemes are designed by combing thermal storage with bypass system, considering different thermal storage sources. Through simulation, the changes in indicators of different schemes, such as the minimum power generation load rate, thermal storage load reduction number, compensation for increased peak shaving capacity and coal consumption costs, are studied in the heat storage initial range from 30%THA to 50%THA. The results show that, the minimum power generation load rate of the schemes with multiple parallel heat storage sources are lower than that of the schemes using a single heat source. Scheme VII with three parallel heat storage sources can reduce the minimum power generation load rate to below 18% under different initial heat storage conditions. However, in the Scheme I with superheated steam heat storage, the load reduction number of heat storage exceeds 2.00, and the load reduction capacity per unit of heat storage power is the largest. As the load rate of the initial heat storage condition decreases, there is a maximum compensation for the annual increase in peak shaving capacity, and the compensation for multiple thermal storage heat source schemes is greater than that for a single heat source scheme. The annual increase in coal consumption cost of the scheme including low-pressure bypass heat storage is much higher than other schemes, but it will decrease with the initial working condition of heat storage.

A novel type of integrated chemical chain hydrogen production CO₂ zero emission solid oxide fuel cell/gas turbine/organic Rankine cycle hybrid power system is proposed, which achieves efficient power generation while efficiently separating and capturing CO₂. The system uses methane as fuel and generates hydrogen gas through chemical chain reactions to enter the fuel cell, avoiding carbon accumulation inside the cell. The anode outlet circuit of the cell is connected to the chemical chain, and the gas from the fuel reactor outlet and the cathode outlet of the cell enters the gas turbine to do work. The exhaust waste heat is recovered and utilized by the organic Rankine cycle system, further improving the system efficiency. A complete system model was established and thermodynamic performance analysis was conducted on the system, obtaining the variation laws of system performance with fuel flow rate, fuel utilization rate, battery working temperature, and system working pressure. The results showed that the comprehensive energy utilization efficiency of the system could reach over 74.10%, the electrical efficiency could reach over 62.42%, and the exergy efficiency could reach 57.73%. Sensitivity analysis showed that the system performance reached its optimum when the system working pressure reached 7×10⁵ Pa.

Large-scale hydrogen production technology from renewable energy such as solar power and wind power has become an important pathway for the consumption of renewable energy and the achievement of “dual carbon” goals. The policies and strategic layout of hydrogen energy at home and abroad are introduced, and the advantages and technical bottlenecks of water electrolysis technologies are analyzed. Moreover, the classification, coordination control optimization and energy management of large-scale renewable energy hydrogen production systems are sorted out. In view of the current development status of hydrogen energy in China, a brief analysis of the current installed capacity and the cost is performed, providing a reference for the construction of green hydrogen production system and the clean substitution of terminal energy in China.

With the grid-connection of renewable energy systems, more coal-fired units are required to participate in deep-peak-shaving and quickly respond to the automatic generation control command. Therefore, the controllers of coal-fired units should not only have satisfactory dynamic performance but also have strong robustness. However, the tuning of proportional-integral (PI) controllers which are widely applied to coal-fire units usually takes the dynamic performance into account and robustness in the application of PI controller parameter tuning is lack. Thus, the maximum-sensitivity-constrained desired dynamic equation (DDE) PI is proposed to obtain good dynamic performance and strong robustness. Simulations and field tests on the hot primary air system of the coal pulverizer indicate that, the proposed control method has better disturbance rejection performance and stronger robustness, which can effectively handle with uncertainties caused by the wide load variation of the unit.

In the context of building a new type of power system with new energy as the main body, it is required that thermal power units undertake more peak shaving tasks, and coupling heat storage tanks is one of the effective ways for units to improve the peak shaving capability. In order to solve the operation scheduling problem of heat storage tanks and units in the context of peak shaving auxiliary service market, thermal system simulation is conducted on combined heat and power (CHP) units to obtain coal consumption and operational safety zones that reflect the actual operating conditions of the units. After that, an optimization model for the CHP system coupled with heat storage tank is established. Aiming to maximize the net profit of the system, this article intelligently optimizes the hourly operation scheduling of a certain CHP and heat storage tank. The results show that, the heat storage process of the thermal storage tank occurs during the electricity price period, and the heat release process varies depending on the heating load. During the high cold period with high heat load, heat is only released during the electricity price valley period, while during the early and late stages with low heat load, heat is released during the valley and peak periods. The net income of the system decreases with the increase of heating load. Running the entire heating season with the optimized scheduling in this article can increase revenue by 21.13 million yuan per year, with a static investment payback period of 5.22 years.

In the context of “carbon peak” and “carbon neutrality”, using renewable electricity to electrolyze water to produce hydrogen and synthesize ammonia can not only consume renewable energy and solve the problem of hydrogen storage and transportation, but also promote the green transformation of the conventional ammonia synthesis process. To investigate the effect of different hydrogen production schemes on technical and economic performance of the synthetic ammonia system, the system thermal and economic performance of three hydrogen production schemes, including proton exchange membrane electrolyzer hydrogen production, proton exchange membrane electrolyzer and alkaline water electrolyzer hydrogen production in a 1:1 ratio, and alkaline water electrolyzer hydrogen production, are compared and analyzed. The hot and cold integration of the synthetic ammonia system with coordinated hydrogen production by proton exchange membrane electrolyzer and alkaline water electrolyzer is analyzed by combining pinch analysis with mathematical programming. The results show that, the system exergy efficiencies of the above three hydrogen production schemes are 60.3%, 56.1% and 52.5%, respectively, and the carbon emissions of ammonia also increase due to the increase in net power consumption of the system. Benefiting from alkaline water electrolyzer’s mature hydrogen production process, the alkaline water electrolyzer hydrogen production scheme has the shortest investment payback period of 6.4 years, while the proton exchange membrane electrolyzer hydrogen production scheme has the longest investment payback period of 12.8 years. The thermal integration analysis of the synthetic ammonia system for the coordinated hydrogen production of proton exchange membrane electrolyzer and alkaline water electrolyzer shows that the low-temperature waste heat below 100 ℃ in the system is released to the environment via cold utilities. In addition, increasing the operating temperature of the electrolyzer is beneficial to improving thermal performance of the system, while lowering electricity price and increasing the annual operating hours of the system will help to improve the economic performance of the system.

The early faults of sliding bearings are highly concealed. To accurately predict their vibration amplitude, a deep learning model incorporating a YOLOv8-optimized CBAM attention mechanism is proposed. The CBAM module is embedded between the Backbone and Neck to enhance the model’s focus on critical vibration features. Additionally, an improved complete intersection over union loss function is employed to enhance object detection accuracy. Considering the nonlinear and non-stationary characteristics of vibration data, the empirical mode decomposition (EMD) method is integrated into the model to improve the accuracy of vibration state prediction. The experimental results show that, on the 600 MW steam turbine operation dataset, this method improves the detection accuracy by 2.85 percentage points and 8.50 percentage points compared with that of the conventional YOLOv8 and YOLOv7, respectively. Moreover, the root mean square error (RMSE) is reduces, and the mean absolute error (MAE) decreases. Furthermore, in high-noise environments, the model’s error fluctuation reduces by 30% compared with that of the conventional methods, demonstrating stronger generalization ability and stability.

Ammonia-coal co-firing is one of the important ways to achieve carbon reduction of coal-fired thermal power units, but the research on high proportion ammonia co-firing is rare. In order to further explore the feasibility of high-proportion ammonia co-firing, the mechanism model of ammonia-coal co-firing is established, and the ammonia-coal co-firing and pure ammonia combustion process of 4 MW boiler is simulated by using computational fluid dynamics (CFD) method. The error between CFD calculation results and experimental data is less than 3%. The experimental results show that, when ammonia is co-fired with coal, the flame temperature decreases by about 30 ℃ and the carbon dioxide volume fraction decreases by about 20% for every 20% increase in the co-firing ratio. When the ammonia co-firing ratio is increased from 0 to 40%, the NO volume fraction at the furnace outlet increases by about 77.33%, and the carbon content in fly ash increases from 4.65% to 6.16%; when it is increased from 0 to 60%, the NO volume fraction increases by about 136.44%. When excess air ratio of ammonia-coal co-firing is 1.15, the fuel burnout and nitrogen oxide generation are optimized. The two-stage input of ammonia fuel can reduce the NO volume fraction at the furnace outlet by 31.07% compared with the ungraded input. Compared with the combustion flame of coal combustion and ammonia-coal co-firing, the flame temperature of pure ammonia combustion is lower, the ignition distance is longer and the tangent circle diameter is larger. When pure ammonia is fired, the NO mass concentration at the furnace outlet is 475 mg/m³, and the escaping ammonia concentration is close to 0.

Focusing on the photo-thermochemical water splitting hydrogen production technology, where photoreaction and thermal reaction are carried out sequentially, the CeO₂ synthesized by sol-gel method and its metal-doped catalysts were taken as the research objects to carry out experimental tests, through which the effects of photoreaction in generating oxygen vacancies and thermal reaction in hydrogen production were investigated. During the photoreaction, CeO₂ catalysts doped with three elements (Fe, Cu, Zn) at three different ratios (5%, 10%, 15%) were used. The metal-doped catalysts were characterized by several methods, such as X-ray diffraction (XRD), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR), photoluminescence (PL), ultraviolet visible diffuse reflectance spectroscopy (UV-Vis DRS), inductively coupled plasma (ICP), and BET specific surface area testing method. The results indicate that, the 10% Cu-doped CeO₂ catalyst exhibits the best photothermal hydrogen production performance. This is attributed to the smallest size of Cu nanoparticles, which results in the smallest bandgap width for the Cu-doped CeO₂ catalyst. Consequently, it can absorb higher energy photons, enhancing the light absorption capacity, and improving the separation and recombination rates of photogenerated charge carriers. This facilitates the formation of photogenerated oxygen vacancies, thereby enhances the hydrogen production capability during the thermal reaction process.

To solve the problem of severe ash accumulation and slagging on heating surface of boilers caused by a large proportion of blended economic coal, based on the close relationship between the ash fouling layer and the flue gas flow field parameters, the concept of cross-sectional “ash fouling characteristic field” is proposed, and a new intelligent soot blowing control system for boilers is developed, which includes functions such as characteristic field detection and generation, and benchmark field prediction. By comparing the difference in “drop value” and “concentration” between the benchmark feature field and the current feature field, the system can timely and accurately determine the appropriate blowing time, achieving “intelligent perception and on-demand blowing”. The new system solves the problem of lack of measurement points and low accuracy in existing model calculation methods, overcomes the disadvantage of high equipment cost in furnace observation methods, and uses on-site full section data collectors combined with intelligent prediction models for ash pollution characteristic fields to achieve low-cost and high-precision detection of ash and slag accumulation, effectively solving the problems of over blowing and under blowing. The actual application effect of the power plant shows that, after the new system was put into use for 3 months, the monthly blowing frequency decreased by 19.6%, and the monthly blowing steam consumption decreased by 229.0 tons, which is equivalent to a direct economic benefit of 284 000 yuan per year. In addition, the system also brings multiple indirect benefits, such as avoiding sudden coking that causes the unit to stop, extending the service life of the heating surface, and avoiding delayed soot blowing that leads to a decrease in boiler efficiency. The relevant control optimization experience can be used as a reference for similar units in the future.