According to GB/T10184—2015, the calculation model of blast furnace gas boiler efficiency is constructed, and the calculation method of blast furnace gas boiler efficiency is analyzed. The results show that the calculation methods of gas moisture content and low-level calorific value are different due to the difference of gas benchmarks.Three methods for solving the excess air coefficient, actual flue gas volume and CO₂ content in the flue gas are proposed for blast furnace gas boilers, and a correction method for exhaust gas temperature of blast furnace gas boilers with gas heaters is proposed;The calculation of some formulas in the GB/T10184—2015 needs to be further discussed, and appropriate modifications can be made.

Geothermal power generation, as one of the main ways to develop and utilize geothermal resources, is of great significance to promote the low-carbon and clean energy structure and the realization of the “dual carbon”. Firstly, the development history of geothermal resources in the world is analyzed. Then, main geothermal power generation technologies such as dry steam power generation, flash steam power generation, binary cycle power generation and wellhead power generation technology are overviewed. On this basis, the hot dry rock power generation, thermovoltaic power generation, supercritical CO₂ cycle power generation, combined power generation technology and multi-energy eomplementary power generation technologies such as geothermal-solar, geothermal-wind, geothermal-biomass, and geothermal-ocean energy, are elaborated in detail. Finally, combining with the current situation and existing problems of geothermal power generation in China, some suggestions for the development of geothermal power generation are put forward, to provide reference for the future development of geothermal power generation.

To address the demand for low-carbon transition in coal-fired power plants, ammonia, as a zero-carbon fuel and efficient hydrogen storage carrier, provides a novel pathway for carbon reduction in the thermal power industry. The key technologies and research advances in green ammonia synthesis, storage, transportation, and ammonia-coal co-firing are systematically reviewed from the perspective of the “production-storage-transportation-utilization” whole industry chain, and the economic feasibility is also evaluated. The study reveals that, the second-generation low-temperature and low-pressure synthesis technology (Fe/Ru catalysts) exhibits the greatest industrial potential for green ammonia production, but requires breakthroughs in enhancing catalytic activity and dynamic matching technologies for renewable energy-based hydrogen-ammonia synthesis systems. It is urgent to develop 100 000-ton-level cryogenic storage tanks and long-distance liquid ammonia pipelines, and establish a “West-to-East Ammonia Transmission” network to support large-scale applications. Ammonia-coal co-firing can achieve NO_x emissions comparable to pure coal combustion by optimizing ammonia injection positions (post-injection in low-oxygen zones), air staging (equivalence ratio of 1.1~1.3 in primary zone), and ammonia blending ratios, alongside designing low-NO_x co-firing burners. However, the weakened radiative heat transfer and enhanced convective heat transfer post-co-firing necessitate compatibility adjustments in boiler steam-water systems. When the cost of renewable electricity decreases to 0.10 yuan/(kW·h) with carbon price exceeding 370 yuan/t, or by utilizing curtailed wind/solar power (with near-zero electricity costs), green ammonia is more competitive than coal. In the future, it is necessary to promote the implementation of technology through green ammonia cost reduction, carbon price mechanism and policy support. This study provides comprehensive technical references and economic optimization strategies for scaling up green ammonia co-firing in coal-fired power plants.

When multiple units are used for combined heating, the distribution of thermoelectric loads among the units significantly affects overall energy consumption. For a thermal power plant where Unit 1 and Unit 3 adopt a dual-mode coupled heat-supply method with zero output of the low-pressure cylinder and steam extraction, and Unit 2 and Unit 4 adopt a triple-mode coupled heat-supply method with high back-pressure, heat pump, and steam extraction, an off-design condition model was established using EBSILON software. The thermoelectric characteristics and energy consumption characteristics were analyzed by adjusting parameters such as main steam flow, zero output steam volume of the low-pressure cylinder, heat supply power of the heat pump, and high-back-pressure heat-supply flow rate. The operational boundaries of electrical and thermal loads and the relationship between coal consumption and thermoelectric load were fitted using the least squares method. Under the fixed boundary conditions for the entire plant’s heating load and power supply load, the optimization of thermoelectric load distribution was achieved using particle swarm optimization. The results indicate that large-capacity high back pressure heat pump units should provide heat load, and small-capacity high back pressure heat pump units should provide electric load. After optimization, the total coal consumption of the whole plant was reduced by 0.6~10.0 t/h, resulting in a degree of optimization of 0.3%~3.9%.

With the transformation of the power system to low-carbon, the proportion of new energy installed capacity is increasing year by year, renewable energy power generation has the characteristics of intermittent, the main power generation period and peak power consumption period are misaligned, there is an imbalance between supply and demand, and the demand for flexibility in power balance is intensified, and long-term energy storage power stations have become a magic weapon to solve the problem. According to the development of long-term energy storage technology, the technical characteristics, advantages and current bottlenecks of pumped storage, compressed air, lithium-ion batteries, flow batteries, molten salt heat storage, and hydrogen energy are analyzed, and the typical application projects of the above energy storage technologies are analyzed. Then, the typical scenario applications of energy storage are analyzed from different sides of the power supply side, the power grid side and the user side, and the application comparison of seven energy storage technologies in multiple scenarios such as energy transfer, auxiliary services, black start, and smooth new energy output is expounded. The technical parameters, battery selection, system wiring, energy management and other issues of chemical energy storage demonstration project, heat storage demonstration project and mechanical energy storage demonstration project were summarized and analyzed, and finally the future energy storage power station technology was prospected.

With the rapid development of energy storage industry and the continuous increase in the installed capacity of energy storage power stations, safety accidents in electrochemical energy-storage power stations have become increasingly frequent, and safety issues have gradually become a key factor restricting the large-scale development of the industry. Therefore, the current policies and standards related to safety risk assessment of electrochemical energy storage power stations at home and abroad are systematically reviewed at first. Then, by analyzing typical safety incidents of electrochemical energy storage power stations, the safety risk points of such power stations are summarized. Based on this, the research progress of the theory and evaluation methods of safety risk assessment of electrochemical energy storage power stations is summarized, from the aspects of battery body, power station working environment, external stimulation and human factors. Finally, the safety development of energy storage power stations in the future is discussed from improving the safety evaluation policies and standards of energy storage power stations, enhancing the construction of the safety assessment system for energy storage power stations, improving the safety and operation management system of energy storage power stations, and strengthening the cultivation of professionals in the energy storage field. It is hoped that this will provide some references for subsequent related researches.

Ammonium bicarbonate is a potential denitrification reducing agent that can efficiently produce ammonia gas through direct solid pyrolysis. The pyrolysis reaction of ammonium bicarbonate solid is numerically simulated, a pyrolysis ammonia production system suitable for coal-fired power plants is designed, and the economic feasibility of the ammonium bicarbonate pyrolysis ammonia production process is analyzed. The simulation results show that, the pyrolysis process of ammonium bicarbonate favors the atmosphere pressure and the conversion rate of pyrolysis rapidly increases when the reaction temperature is above 110 ℃. The pyrolysis system of ammonium bicarbonate for a 660 MW unit has been designed and calculated. An external heating pyrolysis reactor is adopted to realize the utilization of waste heat and stable solid feeding. Steam or flue gas from the coal-fired power plant is used as the heat source for pyrolysis. At 110 ℃, a conversion rate of 95% can be reached within 10 minutes for ammonium bicarbonate feed. Compared with the urea hydrolysis process, the equipment cost, land occupation and operating cost of the ammonium bicarbonate solid pyrolysis process all significantly reduce, showing good prospects for promotion and application.

With the increasing penetration rate of renewable energy in China’s power system in the future, the stability of the system will face more severe challenges. Long-term energy storage technology plays an important role in balancing grid demand, improving grid stability, promoting the consumption of renewable energy, and promoting green and low-carbon development in the power system. Long-term energy storage has a wide range of application scenarios on the power supply side, grid side, and load side of the system, which is of great significance for the development of China’s new power system. Firstly, the characteristics and development trends of the current new power system are introduced, and the supporting role of long-term energy storage technology in the new power system is analyzed. Then, the technical principles and routes of five long-term energy storage technologies, such as the compressed air energy storage, lithium-ion battery energy storage, liquid flow battery energy storage, molten salt energy storage, and hydrogen energy storage, are summarized. The advantages and disadvantages of various long-term energy storage technologies are also analyzed. Finally, the future application prospects of long-term energy storage technology in the new power system are discussed.

Carnot battery (CB) is an energy storage technology with the advantages of high energy storage density and low investment cost. The single-stage heat pump of basic Carnot battery have a low coefficient of performance (COP) under high energy storage density conditions, resulting in a phenomenon of high quality but low utilization of heat. In order to solve this problem, a CB using cascaded heat pump (CHP) and supercritical organic Rankine cycle (ORC) is proposed. Through modeling and analysis, the optimal combination of CHP-CB working fluids is obtained, and the effects of waste heat source temperature, high and low temperature heat storage tank temperature, CHP intermediate temperature on system COP, energy conversion efficiency, energy storage density (E_D) and system exergy loss are discussed. The results show that under high energy density conditions, the COP of the CHP-CB is about 23.5% and 26.9% higher than that of the basic CB when the temperature of the low-temperature storage tank is 50 ℃ and 32 ℃, respeetively. When the temperature of the low-temperature storage tank is 30 ℃, the energy conversion efficiency of the CHP-CB can reach 63.11%. The E_D can reach 13.9 kW·h/m³ when the temperature difference between the high- and low-temperature storage tank is 93 ℃, and cascade heating for the heat storage working fluid can be realized.

Phosphate ester fire-resistant fluids, serving as hydraulic working medium for the speed regulation system of steam turbines, play a crucial role in the normal operation of steam turbines. Currently, imported products dominate the phosphate ester fire-resistant fluids market for the speed regulation system of steam turbines in domestic power generation units. To break the power industry’s high dependence on imported fire-resistant fluids, it is imperative to develop domestic phosphate ester fire-resistant fluids through independent research and application. Through performance evaluation of various domestic tri-aryl phosphate esters, tri-(dimethylphenyl) phosphate was identified as the optimal choice for domestic fire-resistant fluid development. Via oxidation and adsorption refining processes, the stability of the domestic tri-(dimethylphenyl) phosphate was significantly enhanced, resulting in the successful development of high-performance phosphate ester fire-resistant base oil. After the research on various additives, an optimized additive formulation was established, ultimately producing high-performance phosphate ester fire-resistant fluid that meets the new fluid requirements specified in Guide for Operation and Maintenance of Phosphate Ester Fire-resistant Fluid Used in Power Plant (DL/T 571—2014). Static and dynamic simulated aging tests demonstrated that the domestic phosphate ester fire-resistant fluid exhibits superior anti-aging performance compared to the commercially available alternatives. Following one year of industrial demonstration in power generation units, the fluid maintained new-oil quality standards throughout the application period, with the turbine governing system operating normally.