Three-dimensional computational fluid dynamics simulations are performed for a 650 ℃ grade 1 000 MW ultra-supercritical swirl-opposed firing boiler with low NO_x combustion in the furnace. The flow and combustion characteristics in the furnace and the NO_x concentration in the flue gas are investigated under various conditions of overfire air. It is shown that setting a staggered overfire air and injecting the lower OFA with the angle 15°downward into the furnace is helpful to reduce NO_x concentration and improve the burnout rate. A lower overfire air ratio results in a higher temperature in the region of the combustor and a shorter distance between the high-temperature region and the heating surface. As the overfire air ratio increases, the NO_x concentration of the flue gas at the exit of the furnace first decreases and then increases, and the optimal overfire air ratio is around 33.9%.

The dynamic model of resistive type molten salt heater was established by Dymola software, and the transient characteristics and internal temperature field of resistive type molten salt heater under electrical load and molten salt flow disturbance and different arrangement modes were studied on the basis of verifying the effectiveness of the model. The results show that the influence of large disturbance of electric load and molten salt flow on the dynamic characteristics of resistance type molten salt heater tends to be the same, and reaches its limit condition at 110 s and 105 s respectively. However, the occurrence of the limit condition can be greatly delayed when the two disturbances are coordinated. Multiple electric heaters arranged in series or in parallel can slow down the change of molten salt temperature, but increase the system cost. The research conclusion can provide reference for the design, control and debugging of resistance molten salt heater.

An effective disposal method of municipal sewage sludge is burning sewage sludge together with coals in coal-fired circulating fluidized bed (CFB) boilers. At an appropriate weight ratio of sewage sludge in fuel blend, the co-combustion of sewage sludge and coals will not cause significant adverse effects on power plant production, and make use of the calorific value of sewage sludge. This study summarizes the progress of research and application in CFB boilers co-firing coal and sewage sludge, involving the emissions and controls of pollutants during the co-combustion of sewage sludge and coals, the weight ratio of sewage sludge in fuel blend under the reliable boiler operation, and sludge drying. The operational problems associated with the co-combustion of wet sludge and coals are analyzed. The applications of coal-water slurry suspension combustion technology and oxygen-enriched combustion technology in the disposal and utilization of sewage sludge are presented. The study points out that the drying and incineration of sewage sludge combined with advanced flue gas purification technology is one of the mature processes for the application of coal-fired CFB boilers in sewage sludge incineration, which can avoid the environmental impact of odours generated during the storage, drying and transportation of sewage sludge, and provide effective controls of a variety of pollutants. The conclusions of investigation and analysis can provide a reference and basis for the design and safe operation of CFB boilers co-firing coal and sewage sludge.

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.

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.

The optimal scheduling of energy systems is important in ensuring the balance of energy supply and demand. Quantitative comparative studies of the development status, hot spots and trends in this field at home and abroad for more than 30 years, the research of energy systems optimal scheduling was analyzed in the CNKI and WoS databases from 1990—2022 by CiteSpace software. The results show that this field is in the conventional scientific stage but the literature has a high growth rate, the domestic literature growth rate is faster than the international and the inter-institutional exchange is close; the foreign hotspots are optimization algorithms, uncertainty and stability control for microgrids, dynamic scheduling with energy storage for integrated energy system (IES), as well as reinforcement learning and game theory for scheduling technique; the domestic hotspot trends are algorithms, dynamic optimization/bilayer optimization/time-sharing tariffs, multi-intelligent bodies, demand side management and deep learning for microgrids, as well as uncertainty, energy hubs, electricity to gas, integrated demand response, data driven, carbon trading, carbon capture and reinforcement learning for IES. The results show heuristic algorithms and deep learning techniques are expected to achieve a paradigm shift in future large-scale energy systems.

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.

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.