Coupled with the energy storage system can improve the peak shaving capacity of the thermal power unit. To improve the thermoelectric decoupling ability of the combined heat and power unit, a coupled thermal power plant combined heat and power unit with liquid carbon dioxide energy storage system is proposed. The system utilizes the condensate to recover the compression heat of the carbon dioxide during the charge process, and supplies heat to the users together with the heating extraction steam. Besides, the heating extraction steam is employed to preheat the carbon dioxide of the expander inlet during the discharge process. Based on the established thermodynamic models, the thermal performance analysis of the coupled system was carried out with the thermal efficiency, exergy efficiency, and electricity storage efficiency as assessment criteria. The sensitivity analysis results indicate that increasing both the expander inlet temperature and the discharge pressure can obtain a higher system exergy efficiency and electricity storage efficiency; increasing the charge pressure results in a higher system thermal efficiency, while the exergy efficiency first increases and then decreases. The parameter optimization of the corresponding CO₂ energy storage system was carried out under the design parameters. Results show that when the charge pressure is 10.5 MPa and the discharge pressure is 18.0 MPa, the coupled system achieves the optimal efficiency of 64.92%.

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.

In order to study the thermodynamic characteristics of oil-free scroll expander in detail, leakage and thermodynamic model are established based on the first law of thermodynamics and the equation of energy and mass balance. Through the established leakage model, different working condition parameters are further changed to study the changing trend of the leakage in the scroll expander. Under the comprehensive consideration of the influence of heat transfer and leakage on the thermodynamic model, the Euler method is used to solve the established thermodynamic model, pressure, temperature and mass variation of the working medium with the orbiting angle of the main shaft during one operation cycle of the scroll expander are obtained and analyzed. Finally, an experiment platform is set up to test and verify the established thermodynamic model of the scroll expander, which can provide a certain reference for the performance analysis of the scroll expander.

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.

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.

There is a common mismatch between heating supply and demand parameters for industrial heating retrofits of pure condensing thermal power units, and the benefits of thermal power plants can be improved by adopting a reasonable matching scheme of supply and demand parameter. Aiming at the phenomenon of energy mismatch caused by the excessively high extraction parameters of the unit in the industrial heating scene, considering that it is suitable for high-parameter industrial heating, this paper proposes a scheme of using the centripetal turbines for cascade utilization of extraction steam. Taking the industrial heating transformation of a domestic 330 MW cogeneration unit as an example, the thermal system model was constructed to comprehensively evaluate the performance indicators changes of the system from three aspects: thermal performance, exergy environment and economic performance. We also comprehensively compared the effect of upgrading the direct heat reduction and pressure reduction method to the radial turbine power generation steam energy cascade utilization scheme. The calculation results show that under the same heating parameters, compared with the traditional method of temperature reduction and pressure reduction, the comprehensive benefits of the industrial heating steam energy cascade utilization scheme based on centripetal turbine power generation is significant. The specific performance is that under rated conditions, the gross coal consumption rate for power generation can be reduced by 0.89 g/(kW·h), the extraction exergy efficiency can reach 97.66%, and the direct economic benefit is relatively increased by 1.04%, and the carbon transaction cost relative reduction of 0.34%. In addition, the relative advantages of all aspects performance of the system will expand with the increase of the amount of steam extracted by the system for industrial heating.

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.

With the gradual increase in the proportion of new energy in the energy system, increasing the difficulty of AGC frequency regulation of thermal power units, energy storage systems combined with thermal power units AGC frequency regulation technology in China's power industry is developing rapidly. In this paper, the joint frequency modulation system of thermal power unit and energy storage system is studied for the problem of not considering the characteristics of unit variable load process and the lack of relevant evaluation system. Firstly, the thermal unit coal consumption, lifetime, environmental friendliness and energy storage lifetime models are established and uniformly transformed into cost terms during the thermal unit variable load process, thus constituting the corresponding evaluation system. Secondly, the system day-ahead operation optimization model is established, and the system load allocation strategy is further refined by considering the optimization results. Finally, the method proposed in this paper is verified by a case study. The results show that the optimal allocation strategy of joint frequency modulation load of thermal power unit and energy storage proposed in this paper can achieve the purpose of energy storage state management; and through the optimal selection of unit variable load rate and the coordinated response with the energy storage system, the process of unit load change is alleviated the problems of excessive environmental protection and rapid loss of lifespan.

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 view of the current lack of dynamic modeling and analysis of steam modeling in the integrated energy system of industrial parks, the numerical method needs to balance between accuracy and computational efficiency. Based on the basic equation of steam flow, this paper establishes a mathematical model of the hydrothermal process of steam flow. Hydrothermal model is carried out by using a mixture of analytical and numerical methods, and the thermal model is solved by finite difference method for simulation. Compared with the simulation data of commercial simulation software, the solution error of this method is about 0.43%, and the influence of different solution conditions on the thermal process is explored. It was found that an increase in spatial step size would increase the volatility of the temperature curve. As the inner diameter of the pipeline increases, the temperature transfer slows down and the response speed of the model decreases; The initial pressure does not have a significant impact on the solving process and accuracy of the model.