The power industry is the core of the energy system as well as a major carbon emitter. The zero-carbon development of it is the key to the process of carbon neutralization in China. From the perspective of carbon emission, energy resource endowment, industry status, existing problems and development trend, the general situation, low-carbon development path and effect of the electric power industry in the United States, Germany, France and Britain in the European Union was analyzed. Several enlightenments combined with the current situation of the electric power industry in China were summarized, hoping to provide reference for the low carbon development of Chinese electric power industry.

The failure of boiler tubes in thermal power units will cause non shutdown of units and greater economic losses. Deposits in boiler tubes are an important reason for their failure, and reducing deposits in boiler tubes is of great significance to the safe and stable operation of units. It is found that the formation of deposits is related to many factors, such as overheating of furnace tubes, high heat load, poor water vapor quality, water vapor phase transition, working medium disturbance and pipe surface defects. Combined with the flexibility of units, deep peak shaving operation, environmental protection reform and other conditions, the formation mechanism and influencing factors of various types of deposits are analyzed with actual accident case pictures. The effects of overheating, salt concentration and corrosion under scale caused by deposits in furnace tubes are further discussed. The countermeasures for feedwater quality, boiler shutdown protection, unit startup steam purification, unit peak shaving, boiler tube replacement, boiler transformation and maintenance are proposed, which can effectively reduce the generation of boiler heating surface deposits and reduce the risk of boiler tube failure.

Building a new power system focusing on new energy resources puts forward higher requirements for deep peak shaving of coal power unit. Through the requirement analysis of power grid and the comparison of various energy storage technologies, taking the system characteristics analysis of coal power unit as the starting point, a system and a operation mode were given which were based on molten salt thermal storage to assist deep peak shaving of coal power unit. Through theoretical analysis, the calculation methods of the main parameters of subsystems including the heating, heat storage and heat exchange of the molten salt system have been put forward.Taking a 660 MW coal-fired unit as an example, based on the analysis of the thermal boundary and peak shaving demand, the power and connection mode of the electric heating module of the molten salt system are calculated using the calculation method proposed in this article. The types of molten salt and the inlet and outlet parameters of the heat exchange system are selected. The capacity, salt consumption and tank volume of molten salt heat storage are determined. All the results provide reliable data support for accurate accounting of project investment and land occupation. This system and calculation method can provide reference for the preliminary design of similar projects.

To effectively alleviate the high-temperature corrosion of the water-cooled walls on both sides of the opposed wall combustion of a 660 MW unit's boiler and the erosion caused by coal particle impingement, a solution was proposed to deflect the swirl burners near the side walls by 3.5° towards the center of the furnace. This solution was based on an understanding of the causes and mechanisms of high-temperature corrosion and considering the on-site equipment conditions. Numerical simulations were conducted to analyze the combustion in the boiler before and after the burner deflection. A comparative analysis was performed on the changes in temperature distribution, velocity field, concentration field, and particle trajectories resulting from the burner angle deflection. The proposed solution was also implemented in practical engineering. The results of the numerical simulations and engineering application demonstrated that after deflecting the burner angles, the airflow inside the furnace concentrated towards the center, resulting in a reduction of coal particle impingement near the side walls and mitigating erosion. Additionally, the temperature near the side walls decreased, leading to a decrease in reducing atmosphere and a reduced risk of high-temperature corrosion. The combustion efficiency of the boiler remained unaffected. The findings of this study can serve as a reference for preventing and managing high-temperature corrosion and water-cooled wall erosion in boilers of similar types.

Under the background of carbon peak and carbon neutralization, the importance of thermal power generation in northwest China has been further increased. Due to the high proportion of high alkali coal in this area, serious slagging and contamination come out easily in the process of burning high alkali coal in boiler. It's of vital importance to solve the problem of safe burning of high alkali coal ensuring the safety of electric power in China. The present situation of high-alkali coal combustion technology at home and abroad is introduced in this paper. With more than ten years' research, the high-alkali coal combustion technology in China has been improved remarkably, and the related achievements have been popularized and applied in the electric power industry. The blending ratio of high alkali coal in boiler has been increased from less than 60% to more than 90%, though the full burning of high alkali coal has not been realized yet. This paper introduces different technical routes to realize full burning of high alkali coal and analyzes the equipment parameters and operation of typical boilers burning high alkali coal. Generally speaking, pulverized coal boiler, fluidized bed boiler and liquid slag boiler have their own advantages and disadvantages in the adaptability to high alkali coal, with technical bottlenecks to be further studied and broken through. In order to ultimately solve the high alkali coal combustion problem, more new technologies need to be introduced.

Ammonia is a kind of zero-carbon fuel with mature technology and low storage and transportation cost. Partial replacement of coal with ammonia can become an effective way to reduce carbon at the front end of coal-fired units under the dual carbon target. Ammonia fuel is studied as an alternative fuel. The fuel characteristics of ammonia and its blended fuel with typical bituminous coal are studied by using one-dimensional flame furnace and ignition furnace. The ignition performance changes of ammonia/coal blended fuel, the enhanced combustion and pollutant control technology of different proportions of ammonia blended fuel are studied and analyzed in detail. It is found that the pre-blended combustion of ammonia/coal is not conducive to NO_x control. Through fuel grading, combustion excess air coefficient or oxygen control, and air staged combustion, lower NO_x generation concentration and better combustion effect can be achieved during ammonia blending. The operation control suggestions of 25%ammonia mixed with typical bituminous coal are obtained.

The analysis of heat and mass transfer process has important guiding significance for the performance improvement of heat and mass transfer equipment. Through the analysis of the thermal resistance in the boundary layer, the author explores the development of the convective thermal resistance and thermal conduction thermal resistance in the laminar flow of the pipeline in the boundary layer, and establishes a mechanism model (R-P model) that conforms to the macroscopic characterization. The thermal resistance distribution law under the condition of Re and Pr, explored the internal mechanism of laminar flow enhanced heat transfer in the tube, and guided the optimal design of the flow-around structure. The results show that the heat conduction is absolutely dominant in the inlet stage, and the proportion of convection gradually increases after the full development. The mechanism of Re and Pr affecting heat transfer is different. When Re increases, the heat transfer must be strengthened. When Pr increases, it only increases the proportion of convection, and in the range of (Pr<1.8), thermal resistance always plays a major role. At the same time, it was found that adding a turbulent flow structure to the laminar flow in the pipeline would reduce the heat transfer effect.

The carbon content of fly ash in boilers is one of the important indicators of combustion efficiency. This study employs machine learning models to accurately predict the carbon content of fly ash. Firstly, random forest is employed to adjust the frequency of fly ash carbon content data to once per minute, aligning it with the input features to address the issue of imbalanced data collection frequency. Then, a recursive feature elimination method based on random forest is used to extract nine important features out of the original 30 features, reducing feature correlation and improving model accuracy. Subsequently, six machine learning models (linear regression, decision tree, K-nearest neighbors (KNN), random forest, Catboost and XGBoost) are compared for prediction. The results indicate that decision tree, KNN, random forest and XGBoost models perform well, MSE of which on the test are 0.010, 0.009, 0.006 and 0.006, respectively, while linear regression exhibits the poorest performance. The prediction models remain robust under low, medium, and high boiler loads.

Large proportion burning high-alkali coal will cause serious contamination to the heating surface of the boiler, and threat the device security and stable production of the power plant. The article compared flue gas temperature changes of three types of boilers burning Xinjiang Naomaohu high-alkali coal, XRD phase analysis and chemical composition analysis of ash slag was also performed. Analysis results indicate the composition of the ash block developed by short-term bonding is close to that of coal ash, and the texture is loose, and the heating surfaces can be kept clean by soot blowing optimization. The shell-like slag formed by long-term contamination is rich in SO₃ and Na₂O, the degree of sintering is high, and the texture is hard, controlling the flue gas temperature of the heating surface inlet can effectively reduce the fouling and slagging of the tube panel. The flue gas temperature at the convection heating surface inlet with tube panel gaps of about 50 mm should be controlled below 800 ℃, when the gaps are above 200 mm, the flue gas temperature should be controlled below 1 000 ℃. The results of the research can be used as a reference for the same type of boiler burning high-alkali coal.

In order to solve the safety and economic issues of mixed combustion of multiple fuels such as gas, lignite, and coal slurry in power plant boilers, an evaluation method for the blending of multiple fuels was proposed. Firstly the constraints on the moisture, volatile matter, calorific value, and sulfur content of the fuel entering the furnace under different loads are established, based on the fuel characteristics and various requirements for safe operation of the unit, and then the minimum comprehensive power supply cost and the optimal blending scheme for multiple fuels under different loads are determined through blending experiments. The experiments were conducted on a 300 MW power plant boiler, and the results showed that, on the premise of meeting the constraints of the incoming fuel, the fuel cost for power plants can be decreased by increasing the proportion of economic coal blending based on the principle of minimizing comprehensive power supply costs. This study will provide important reference for the study of multi fuel blending in power plant boilers.