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.

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.

Through the analysis of the principle of the existing methods for determination the water content in oil and the components of gear oil, as well as monitoring needs of water content in gear oil, it is found that the existing methods can not accurately and quickly detect the water content in gear oil. the new gear oil and running gear oil for wind power was selected as experiment object, through study of selection of test conditions and the accuracy of the results, it is found a method that can accurately and quickly detect the water content in the gear oil. This method is a combination of the Karl Fischer coulometry water analyzer and the heating furnace. With compressed nitrogen or air as the carrier gas, after the carrier gas is dried through the molecular sieve, it cross the sealed test bottle containing 1g oil sample and 1mL n-heptane by the sleeve air needle, Heat the bottle at 150 ℃, and transfer the water in the oil sample to enter the Karl Fischer water analyzer for detection.

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.

In the study, a computational fluid dynamics (CFD) model based on a 600 MW tangentially coal-fired boiler was established. According to orthogonal conditions (L₁₆(4⁵)), the heat flux distributions of the water-cooled wall under 100% BMCR, 75% THA, 50% THA and 35% BMCR loads were obtained. In addition, the factors also included: primary to secondary air rate, degree of air-staging, swing angles of burners and SOFA nozzles. Then, the spiral water-cooled wall temperature distributions under various conditions were calculated through coupling the heat absorption, temperature calculation and hydrodynamic characteristics of the water-cooled wall. Due to the discontinuity of orthogonal condition, the machine learning was used for predicting the spiral water-cooled wall temperature distribution within the range of parameters covered by orthogonal conditions. The results showed that a wall temperature peak up to 730 K would appear in the area among burner system. The heat transfer deterioration was easy to occur when the flame center height in furnace coincided with the phase change height of the working fluid during the boiler load adjusting process. The goodness of fit R² of the ensemble learning on the training set and the test set of the wall temperature data had reached 0.99, which could be used to predict the wall temperature of the boiler under wide load. At the same time, the machine learning established the mapping relationship between the wall temperature distribution and the operating parameters of the boiler. In the future study, the wall temperature safety of the water wall can be guaranteed by reasonably adjusting and optimizing the operating parameters through the optimization algorithm.

A novel hybrid design that combines solid waste plasma gasification, gas turbine, absorption heat pump, and coal-fired combined heat and power plant has been proposed. In the integrated scheme, medical waste is sent to the plasma gasifier and converted to syngas, which is conveyed into the gas turbine system after the necessary treatment. In terms of waste heat utilization of syngas and flue gas, some are used by the absorption heat pump for heating, and the rest are used to heat the feedwater of the coal-fired combined heat and power plant directly. Based on a typical coal-fired combined heat and power plant, the benefits of this system are examined in terms of both thermodynamics and economics. Once the heat supply and the net electricity from coal remain the same, the net power generated by the waste in the hybrid design is 7.47 MW, while the net waste-to-energy efficiency reaches 47.96%. In just 5.23 years, the initial investment in the proposed system is recouped, and in its 25-year lifetime, the system achieves a net present value of 50 362.94 thousand CNY.

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.

In view of the research situation of backpressure extraction steam turbine technology for ultrasupercritical power generation units, the off-design condition calculation model and exergy analysis model of the unit was established, and the influences of steam mass flow, temperature, pressure, steam turbine back pressure and the BEST heat extraction stage on the thermal performance of the unit were analyzed. The exergy efficiency of unit increased first and then decreased with main steam flow rate, reaching the maximum value (52.42%) when main steam flow rate was 750 kg/s. Exergy efficiency of unit increased with the increase of main steam temperature and pressure but decreased with the increase of turbine back pressure. The thermal performance of unit was more affected by back pressure at low load. In addition, the BEST series has a significant effect on the thermal performance of the unit, and the BEST match degree with the system design scheme is achieved when the series is 4, and the thermal performance is optimal. The calculation method and BEST series selection scheme can provide reference for the scheme design and operation optimization of ultra-supercritical units.