Facing the frequency security problem caused by large-scale integrations of fluctuating new energy, the participation of thermal power units coupled with flywheel energy storage in frequency regulation can effectively improve the active power support capability of the power grid from the generation side, which is an effective guarantee for the frequency security of the power grid. According to the output control strategy and capacity configuration of flywheel energy storage systems, this paper proposed a combined method of flywheel control strategy and capacity configuration for primary frequency regulation to optimize the thermal power unit operations. Firstly, a coordinated frequency regulation control strategy of flywheel energy storage considering the real-time power output of thermal power units is designed. An economic evaluation model considering the primary frequency regulation benefit of power plants is proposed, and a refined particle swarm optimization algorithm is utilized to tackle the problem. Finally, the actual data of a 315 MW unit in a power plant from the northern part of China are simulated and verified. The result shows that the proposed integrated configuration strategy can effectively improve the frequency modulation effect of the power grid while taking the cost of energy storage investments into account. The research results are of great significance for promoting engineering applications of flywheel energy storage participating in frequency regulation services.

In order to solve the problems of user account management and security protection in current group information system, this paper proposes a three-in-one AAA system of account, authentication and audit based on zero-trust architecture. Firstly, it describes the function of user management, authentication authorization, user audit and other modules of the AAA system. Secondly, in view of the conventional network boundary protection problem, the authentication authorization method based on zero trust architecture is applied to identify the business scenario, thus to ensure the reliability of the business system environment. Lastly, it illustrates the logic of the AAA subsystem and group-level system development platform configuration. The proposed AAA system can effectively improve the business security of group-level enterprise information system, compensate for the security issues of user login account under zero-trust environment, and further improve the security protection ability of network equipment, application equipment, system and application management in group-level enterprise.

The coupling of thermal units with flywheel energy storage system can effectively improve the frequency regulation performance of AGC, solve the problems of long response time, slow climbing rate and low regulation accuracy of thermal units when tracking AGC commands, and obtain the auxiliary revenue of frequency regulation. This paper proposes a flywheel energy storage system control strategy for engineering practice, taking into account the requirements of the "two rules" of the Northwest Power Grid on AGC climbing performance, to improve the performance index of the combined system participating in AGC frequency regulation while preserving flywheel power. The results show that the proposed strategy improves the performance of the combined thermal power units and storage systems in AGC, and the economic efficiency of the power plant is significantly improved.

Flue gas recirculation (FGR) is an important technical mean to improve the safety of circulating fluidized bed (CFB) boiler and reduce the generation of NO_x under low-load operation. In the present work, the relationships between temperature distribution of the boiler, NO_x, CO mass concentration and O₂ volume fraction of the flue gas at furnace outlet, the combustible matter content of fly ash and bottom slag and the flow rate of FGR under the load of 20%, 30% and 40% BMCR (boiler maximum continuous rating) were studied using one-dimensional chamber CFB combustion quasi-static model at a supercritical 350 MW CFB boiler. The results show that both the bed temperature and furnace exit flue gas temperature decrease with the increase of FGR flow rate, which the former decreases less than the latter. The temperature difference between the upper and lower furnace gradually decreases with the increase of FGR flow rate, which is more significantly affected by FGR flow rate at lower loads. The NO_x mass concentration of flue gas at the furnace exit shows a trend of decreasing first and then increasing with the increase of FGR flow rate, and the existence of the optimal FGR flow rate can make the unit operation economically and environmentally friendly. In addition, with the increase of the FGR flow rate, the CO mass concentration at the furnace outlet, combustible matter content of fly ash and bottom slag shows an increasing trend. The FGR significantly reduces the primary air oxygen volume fraction while ensuring that the fluidized air flow rate in the dense phase area is always higher than the protection value, which ensures the operation safety of the boiler under low load furtherly.

Oxidation reduction potential (ORP) analysis method has been gradually used in the field of limestone-gypsum wet desulfurization slurry oxidation control, but there is a lack of corresponding theoretical research. In this paper, firstly, the standard electrode potentials of each pair in the slurry oxidation process, E^θ(O₂(αq))/H₂O and E^θ(S(Ⅵ)/S(Ⅳ)), were obtained based on density functional theory and acid dissociation equilibrium calculation; and the standard electromotive force of each reaction was calculated. Then, based on the main reaction of slurry oxidation, 2HSO₃^–+O₂→2H⁺+2SO₄^2–, the theoretical calculation model of the electromotive force of the reaction system was established by the Nernst equation. It was found that the measured ORP of the electromotive force of the reaction system was quite different from that by theoretical calculation, which meant the Nernst equation was not suitable for the slurry oxidation system. Finally, a good multivariate linear fitting relationship between the measured ORP, pH, ln(c(Ca²⁺)), ln(c(HSO₃^–)) and ln(c(O₂)) was established by the stepwise regression. The results indicated that the process of slurry oxidation was not only related to the single indicator of ORP, but also controlled by pH, calcium ion and dissolved oxygen concentration. When ORP is used as the oxidation control indicator of wet desulfurization slurry, the influence of pH, calcium ion and dissolved oxygen concentration should be taken into account at the same time.

It is known that the interdiffusion at the aluminide coating/matrix interface during the long time exposure at high temperature would change the microstructure of the matrix and deteriorate the mechanical properties of the matrix. To analyze the high temperature strength of aluminide coating on T92 steel for ultra-supercritical unit, aluminide coating is prepared on the inner wall of T92 steel boiler tube by low temperature powder embedding method, and the tensile test was carried out at room temperature to 625 ℃ and the durability test was carried out at 625 ℃ environment. The effect of aluminide coating on the tensile properties and durability life of T92 matrix are studied by combining scanning electron microscope (SEM), optical microscope (OM) and X-ray diffraction analysis(XRD). The results show that the aluminide coating prepared on the inner wall of T92 boiler tube by low temperature powder embedding aluminizing, which is metallurgically combined with the matrix, has a double-layer structure, and each layer is continuous and uniform. The total thickness of the prepared aluminide coating is about 30.4 μm. The coating has columnar crystal structure and the surface is cracked in the room temperature is increased to 625 ℃. During the creep rupture process at 625 ℃ environment, FeAl coating have many cracks, but the crack depth is shallow and very few cracks extend to the matrix. The coating peels off locally large strains under the high stress state. It can be concluded that even deforms of the aluminide coating occurred during the long-time creep process, it can still has good metallurgical bonding with T92 matrix.

In order to well evaluate the availability of electrochemical method using to detect the creep damage of martensitic heat resistant steel, a set of T92 internal pressure creep test samples with different creep damage degrees were selected. The microstructure evolution in the process of creep, especially the Laves phase precipitation behavior, was systematically characterized and analyzed; meanwhile, electrochemical response of Laves phase in alkaline were also investigated in detail. According to the scanning electron microscopy(SEM), transmission electron microscopy(TEM) and electron probe X-ray micro-analyzer(EPMA) results, the Laves phase in T92 precipitated and grew rapidly during the internal pressure creep process. Its particle size and area percentage gradually increased, clustered and with element segregated and redistributed. According to potentiodynamic polarization curve in NaOH solution, Laves phase can selectively dissolve in strong alkali solution. When the concentration of NaOH reaches 8 mol/L, the current peak and corresponding electric value of selective dissolution of Laves phase are well correlated with the internal pressure creep time. In conclusion, the potentiodynamic polarization curve of T92 in strongly alkaline solution can effectively reflect the content of Laves phase, varying in consistent with its electric quantity; and can further associate with creep life damage. It is promising to be used as a nondestructive testing technology for the creep life assessment of pipelines in the field.

Energy conservation and emission reduction work have attracted global attention. Accelerating lowcarbon transformation work has also reached a consensus in the shipping industry. Among them, hydrogen energy ships have good development prospects. In the face of the problem that hydrogen energy ships have no stable hydrogen source, it is urgent to find a stable hydrogen source for hydrogen energy ships. This paper introduces the development status of hydrogen production from offshore wind power and hydrogen energy ships, breaks the traditional concept of hydrogen energy, puts forward the system architecture of hydrogen production and hydrogenation on offshore platforms, and uses offshore wind power to directly prepare hydrogen, which provides a new idea for solving the hydrogen source problem of hydrogen energy ships and realizing the consumption of offshore wind power. Through the discussion and economic analysis of the integrated development of offshore wind power and marine ranching hydrogen energy ships, it is found that the integrated development of offshore wind power and marine ranching hydrogen energy ships is economically feasible, will contribute to carbon emission reduction work, and has good development prospects. This paper can serve as a reference for the comprehensive development of offshore wind power and hydrogen ships and put forward the prospect of building offshore hydrogen energy passage in coastal areas.

The flow channel structure at the cathode side is one of the main factors affecting the performance of proton exchange membrane fuel cells. The flow channel at the cathode side needs to discharge liquid water out of the fuel cell in time and make oxygen flow to the cathode catalytic layer as much as possible. Thus, the phenomenon of cathode flooding and concentration polarization is avoided. An innovative 3D cathode side channel, sugar gourd type channel, is designed. The sugar gourd type channel is formed by adding arc-shaped side trapezoidal block based on the traditional straight flow channel. The simulation results show that, compared with the traditional straight flow channel, the current density in the high current density region is increased by about 8%. And because of the special structure of the sugar gourd type channel, the air flow advances to the outlet in the form of pulse decline, and the heat and mass transfer are significantly enhanced. In addition, the influence of arc-shaped side trapezoidal height on overall performance is further explored.

The process of conventional hydrometallurgical recovery of lithium batteries not only consumes corrosive acid and long-time reaction, but also produces secondary wastes. In this paper, microwave-assisted deep eutectic solvent (DES) is used to leach and recover valuable metals from cathode material LiCoO₂ (LCO). The leaching and recovery process is not only green and low-pollution, but also owns a fast reaction rate, good solubility stability of the valuable metal and high purity of the recovered product. Meanwhile, FT-IR, XRD, ICP-MS, SEM and electrochemical analysis methods are used to explore the mechanism of microwave-assisted DES leaching of valuable metals from LCO. The effects of experimental factors on the extraction efficiency of valuable metals are obtained by orthogonal test method. The degree of influence is DES>temperature>liquid-solid ratio>time. Afterwards, according to the results of orthogonal experiments, the single-factor experiments are successively adopted to explore the optimal experimental conditions for microwave-assisted leaching of valuable metals, 99.86%of Li and 99.05% of Co can be extracted under the condition of choline chlorine-oxalic acid (ChCl-OA), 180 ℃, 10 min and liquid/solid ratio (L/S) of 60 mL/g. At this time, Co exists in the leaching solution as formic acid cobalt. Finally, a green and efficient strategy for extraction of valuable metals from spent LiBs (LCO) through microwave-assisted DES is proposed, which provides an important reference method for recovery of valuable metals from spent lithium-ion batteries.