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.

To achieve efficient coupling between coal-fired power plants (CFPP) and compressed air energy storage (CAES), a system that couples the flue-gas side of CFPP with CAES is proposed. During the energy release phase of this coupled system, the flue gas from CFPP is used to heat the high-pressure air before it enters the expander. This avoids introducing additional heat sources, which would increase costs, or extracting steam from the turbine side to heat the high-pressure air, which would affect the output of the thermal power unit. Subsequently, to reduce the effect of extracted flue gas on the operation of a single thermal power unit, a CAES coupled system sharing the flue gas of two thermal power units is established. Based on the above thermodynamic models of the systems, modeling is carried out using EBSILON software and performance analysis is conducted. Then, an optimal economic operation strategy for the plant-level coupled system is proposed. The results show that, at full load, compared with the steam-coupling scheme, the flue-gas-coupling scheme reduces the standard coal consumption rate by 2.15 g/(kW·h), increases the heat consumption rate by 37.06 kJ/(kW·h), raises the energy utilization coefficient by 0.33 percentage point, and decreases the auxiliary power rate by 0.20 percentage point. The overall electrical efficiency, round-trip efficiency, and CAES operating efficiency of the flue-gas-side coupling are all higher than those of the steam-side coupling. After the economic optimization of the plant-level coupled system, the net revenues of four typical days increase by 143 700, 157 600, 188 100 and 208 700 yuan, respectively.

The dynamic models of steam generation system and power generation system are developed to study the dynamic characteristics of power-to-heat molten salt heat storage and power generation system, and the reliability of the models is validated. The dynamic characteristics of the system are analyzed for the disturbance of molten salt work temperature, flowrate and steam valve opening. Moreover, the performance of the system in the load reduction transient process is investigated in the 100%THA~50%THA load interval. The results show that, the main steam temperature and reheat steam temperature respond quickly to the molten salt temperature disturbance, and their response is obviously faster than that of the unit load and main steam pressure. The molten salt flowrate disturbance has a significant effect on the unit load and main steam pressure, and the unit load increases by 12.44% and the main steam pressure increases by 1.18 MPa with 15% increase in molten salt flowrate. The main steam valve opening controls the main steam pressure and load fluctuation. With the addition of the control system, the maximum load reduction rate of the unit in the 100%THA~50%THA load interval is 14%Pe/min with the limiting condition of temperature deviation.

In order to effectively improve the energy efficiency and operational flexibility of solar power generation, an integrated system coupling solar photovoltaic, solar thermal and compressed air energy storage is proposed. During the day, the compressed air energy storage system will store the photovoltaic abandoned power, and transfer the compression heat to the photothermal power station. At night, the compressed air energy storage system releases air and uses water supply of the photothermal power station to heat up, thereby increasing the power generation load of the unit. Based on the system simulation, the coupling scheme is analyzed thermodynamically and economically. The overall generation efficiency of the coupled system is 41.24%, while the overall exergy efficiency is 66.79%. The round-trip efficiency of the compressed air energy storage system is 72.14%, while the exergy efficiency of the compressed air system is 84.30%, both of which have increased significantly. The peaking depth of the coupled system is 7.02% in the daytime and 19.69% in the evening. In addition, the dynamic recovery cycle of the coupling scheme is 3.10 years, and the net present value is 41.350 6 million yuan.

As an emerging large-scale electricity storage technology, the Carnot battery has the advantages of low cost, large capacity, and being free from geographical limitations. Aiming at the current situation that the low discharge cycle efficiency restrains further improvement of round-trip efficiency of the Carnot battery, combined with the heat demand of the thermally integrated Carnot battery and the relatively high discharge efficiency of the Kalina cycle, a heat pumped-Kalina cycle Carnot battery system driven by extraction steam of a coal-fired power station is proposed. A thermodynamic model of the Carnot battery system is established, and the influences of thermal energy storage temperature, temperature difference in thermal energy storage, and ammonia mass fraction on thermodynamic performance of the Carnot battery are mainly studied. The results show that, with different temperature differences of thermal energy storage and at different temperatures, the round-trip efficiency can reach 44.8%~108.0%. With the increase of the ammonia mass fraction, the round-trip efficiency will be significantly improved. However, when the ammonia mass fraction exceeds 90%, the efficiency will drop sharply, and the Kalina cycle is close to a one-component cycle. Therefore, when designing a Carnot battery based on the Kalina cycle, the ammonia mass fraction should be controlled within 80%~90%.

Improving the flexibility of coal-fired power units is the key to achieving a green and low-carbon power system. Molten salt energy storage technology, as a sensible heat energy storage technology, can provide frequency regulation, peak regulation, and industrial heating decoupling support for power generation units. Combining with the engineering application of a coal-fired power unit coupled with molten salt energy storage, the thermal performance of heat storage, heat release and energy cycling are systematically analyzed, and performance evaluation indicators are proposed. The results show that, the molten salt thermal storage system significantly enhances the flexible operation capability of the unit, achieves decoupling between industrial steam supply and deep commissioning peak of the unit, and improves the frequency regulation performance by 150%. The thermal efficiency of the thermal storage system is maintained at around 92%. This study provides a reference for the application of flexibility renovation projects for coal-fired power plants based on molten salt thermal storage technology.

Constructing a large-scale virtual power plant (L-VPP) based on coal-fired units is a vital strategy for achieving “dual-carbon” goals by enabling renewable energy integration and supporting the transition of coal-fired power generation. A dynamic simulation model of the L-VPP and a source-storage frequency regulation control system model are established, which include a 350 MW coal-fired unit, a 100 MW photovoltaic unit, a 90 MW·h battery energy storage system, and internal loads. The frequency response characteristics of the L-VPP are analyzed for various control systems and at different load ramp rates of the coal-fired unit. The results reveal that, the load ramp rate of the coal-fired unit is a critical constraint on frequency response capability when storage capacity is limited. The complementary frequency response characteristics between the source and storage are obtained, leading to a coordinated control strategy that incorporates auxiliary power commands and cyclic determination mechanisms. Simulations demonstrate that the proposed strategy lowers the frequency nadir by 0.06 Hz and shortens the steady-state recovery time by 18.6%. Furthermore, to achieve a steady-state error within the frequency dead band, the load ramp rate of the coal-fired unit is increased from below 3.50 MW/min to 7.00 MW/min. This strategy offers technical guidance for the safe and efficient operation of large-scale virtual power plants.

Co-firing biomass in coal-fired plants is considered as one of the important technologies for achieving carbon emission reduction. Based on the 660MW ultra-supercritical lignite coal fired plant in Inner Mongolia, this study conducted the first domestic experiment on co-firing cow manure. Cow manure is a typical herbaceous biomass. the first domestic large scale coal-cow manure co-combustion experiment in a 660 MW ultra supercritical lignite-fired power unit in Inner Mongolia was carried out. The ability of coal mill to grind biomass and coal mixed fuels was investigated, and the effect of mixing compacted cow manure on the milling performance was analyzed. Moreover, the effects of co-firing compacted cow manure on the combustion characteristics, unburned carbon content in fly ash, boiler efficiency, and pollutant emissions at different loads were studied. The results indicate that, without the addition of new devices, the change in coal mill current before and after co-firing 15% and 20% compacted cow manure with single coal mill changed slightly. With co-firing 15% compacted cow manure and the coal fineness R₂₀₀ increasing from 8.3% to 12.4%, the R₉₀ increased from 35.8% to 40.0%. With co-firing 20% compacted cow manure and the coal fineness R₂₀₀ increasing from 8.3% to 14.4%, the R₉₀ increased from 35.8% to 54.4%. The pressure difference between the coal mill inlet and outlet varied significantly and was closely related to the coal feed rate. With the furnace compacted cow manure co-firing ratio of 2.9% (15% co-firing with coal mill B) and 6.4% (20% co-firing with coal mill B), the changes of exhaust temperature before and after co-firing were both between 1.0~2.5 ℃. With the furnace compacted cow manure co-firing ratio of 7.1% (16.0% co-firing with coal mills B and D) and 8.7% (15% co-firing with coal mills B, C, and D), the exhaust temperature before and after co-firing increased by 3.3 ℃ and 3.6 ℃ at 450 MW and 550 MW, respectively, which was significant. At 250 MW, 450 MW, and 550 MW loads, the change of CO mass concentration was less than 5 mg/m³, and the decrease in boiler thermal efficiency before and after co-firing remained 0.06~0.28 percentage points. Co-firing compacted cow manure can reduce NO_x and SO₂ emissions. When the mixing ratio of compacted cow manure on two and three coal mills was 15% and 20%, the annual CO₂ emission reduction would be 140 312, 210 467, 160 356 and 240 534 tons, respectively.

A comparative test was conducted on operating oil samples from wind turbine gear oil and a fresh oil sample, revealing that the Fe³⁺ content was the most rapidly deteriorating indicator. The SG-PEI adsorbent was prepared by loading polyethyleneimine (PEI) onto a silica gel material (SG) through impregnation modification, and its characteristics were evaluated. The adsorption isotherms and kinetics of Fe³⁺ on SG-PEI were thoroughly investigated. The results indicated that, the adsorption isotherm of Fe³⁺ on SG-PEI conforms to Langmuir model. The saturated adsorption capacity of SG-PEI for Fe³⁺ was 28.71 mg/g, representing a 39.2% improvement compared to SG (20.63 mg/g). The adsorption process of Fe³⁺ on SG-PEI adhered to the pseudo-second-order kinetic model, with adsorption process occurring as a spontaneous exothermic reaction. Under optimal conditions of an adsorption temperature of 60 ℃, an adsorption time of 120 min, and an oil-adsorbent ratio of 100:3, the removal rate of Fe³⁺ from wind turbine gear oil by SG-PEI reached 96.23%, which is 29.43 times higher than that of the 801 adsorbent (3.27%) and 185.06 times higher than that of Al₂O₃ (0.52%). The SG-PEI has a good prospect for applications due to its high adsorption capacity and selectivity for Fe³⁺.

It is crucial to improve the dynamic performance of the yaw system of wind turbines in multiple operating scenarios. Therefore, a predictive control strategy for wind turbine yaw system model based on reinforcement learning is proposed, which achieves multi-objective parameter dynamic optimization through the dual-delay depth deterministic policy gradient (TD3) algorithm. Firstly, a multi-step model predictive controller for the yaw system (YMPC) is established to address the conflicting control objectives of power loss rate and yaw actuator utilization rate. Secondly, based on the optimization objectives and wind conditions of the yaw system, a dual-delay depth deterministic strategy gradient (TD3) intelligent agent is designed to determine the input state, action, and reward mechanism of the YMPC. The TD3 intelligent agent is then used to tune the weight coefficients and control step size of the YMPC. Finally, the effectiveness of this method was validated using typical daily data from wind farms in northern China. The results indicate that the proposed strategy significantly improves the overall performance of the yaw system compared with the YMPC with fixed control parameters.

In light of the intricate nature of surface defects in wind turbine blades, conventional convolutional neural networks face problems such as threshold screening and non-maximum suppression processes, which increase computational complexity and are not conducive to model deployment. A novel defect detection model that integrates real-time-detection transformer (RT-DETR) with YOLOv5 algorithm is proposed. Firstly, the backbone network of YOLOv5 is redesigned based on RepVGG and FasterNet to reduce the computational complexity of the model. Recognizing the presence of small-sized targets within the detection tasks, an efficient channel attention (ECA) mechanism is integrated into the neck network’s feature fusion component, thereby augmenting the expressiveness of the output features. Finally, the detection head of original network is reconstructed with the Decoder from RT-DETR, minimizing the effect of non-maximum suppression on the model’s performance. The experimental results show that, the average detection accuracy and accuracy of YOLO-RT are 87.2% and 92.7%, respectively, on a self-constructed dataset of wind turbine blade surface defects, reflecting improvements of 4.4 and 8.0 percentage points over the original YOLOv5 model. The detection rate reaches 118.3 frames per second, surpassing that of alternative detection models. The enhancements introduced in this algorithm significantly improve both detection accuracy and speed, making it highly suitable for practical applications in detecting surface defects on wind turbine blades.

A resin-based solid amine adsorbent was prepared based on in-situ synthesis technology. The effects of air humidity (30%~90%), adsorption temperature (30~90 ℃) and adsorption time on the adsorption performance of CO₂ were investigated. Moreover, the adsorption kinetic characteristics of the adsorbents at different air humidities were studied. The results showed that, the maximum CO₂ adsorption capacity of the resin-based solid amine adsorbents in the air reached 2.38 mmol/g, and the air humidity and adsorption temperature had significant effects on the adsorption rate. The optimal adsorption efficiency was obtained when the air humidity was higher than 50% and the adsorption temperature was 25~50 ℃. The adsorbent exhibits very good cycle stability due to its excellent high temperature resistance.

For a supercritical carbon dioxide (S-CO₂) recompression Brayton (RB) system with two-stage compression and intercooling process, two system models with different layouts are constructed. The effects of key parameters such as low-pressure stage pressure ratio and split ratio on the system performance are explored. The results indicate that, the minimum and optimum splitting ratios exist for the RB cycle, the two-stage compression cycle of the main compressor (TCIP-RB), and the two-stage compression cycle of the recompressor (RTCIP-RB) under the design conditions. Moreover, the thermal efficiency of the TCIP-RB cycle is higher than that of the other two cycles within a certain range of split ratios. When the above three systems adopt the optimal split ratios, the maximum efficiency of the TCIP-RB cycle is 50.95%, which surpasses that of the RB and RTCIP-RB cycle by 3.20% and 3.98%, respectively. At different low-pressure stage pressure ratios, TCIP-RB and RTCIP-RB cycles have an optimal split ratio to maximize the thermal efficiency of the system, and the maximum thermal efficiency decreases with the increase of the low-pressure stage pressure ratio.

Based on the application of micro-channel printed circuit heat exchangers in fields such as thermoelectric power generation and aerospace, a high-efficiency, low-resistance, and easy-to-manufacture transverse slotted channel is proposed using the theory of boundary layer re-development, and the heat transfer is enhanced. Numerical simulations are employed to study the flow and heat transfer characteristics of both straight and slotted channels. The mechanisms of heat transfer enhancement and flow resistance reduction in the transverse slotted channel are investigated. The results show that the entrance effect can significantly enhance heat transfer with a minimal increase in flow resistance. The transverse slotted channel creates multiple entrance effects in the slotted regions by inducing flow separation, which leads to periodic boundary layer redevelopment, thereby greatly enhancing local convective heat transfer. Additionally, due to the relatively small velocity gradient in the slotted regions, local resistance is effectively reduced. As a result, the proposed transverse slotted channel improves the heat transfer capability of the channel by 2.24%~2.59%, reduces the resistance by 6.66%~7.91%, and increases the overall heat transfer performance by 9.87%~11.02%.

Computational fluid dynamics-chemical reactor network (CFD-CRN) simulation is a suitable method for predicting NO_x emissions from gas turbines. A universal CRN automatic partitioning/solving program was developed and then applied and verified on a natural gas micro-mixing combustor. Through analysis of flow and combustion characteristics in the micro-mixing combustor based on CFD simulation, CRN partitioning criteria are established: firstly, the air and fuel zones are extracted, then major zones along the axial direction are divided, and further the zones are subdivided radially/circumferentially according to fuel-staging locations. The results indicate that, the CRN automatic partitioning/solving program enhances generality by using an XML standardized information interface and is suitable for complex combustor structures. The relative error between the predicted and experimental NO_x emissions under different operating conditions of the micro-mixing combustor is less than 11%, and the influence of CFD grid number on the NO_x prediction by CRN is relatively small. The effect of fuel distribution ratio on NO_x emissions from micro-mixing combustor is analyzed, and a suitable adjustment range is given. The proposed CRN automatic partitioning/solving algorithm has potential applications in predicting NO_x emissions from gas turbines.

An analytical model for a combined heat and power (CHP) system driven by deep geothermal energy based on heat pipes was developed. The dynamic heat extraction characteristics of the heat pipes are obtained through numerical calculations based on the heat pipe-geothermal rock layer model. By analyzing the thermodynamic and thermo-economic performance of the direct expansion CHP system, the effects of heat pipe structure (heat pipe diameter, length, and insulation layer length), operating time, and geothermal temperature gradient on the performance of the system are investigated. The results show that, lower steam condensation temperature of the heat pipes leads to greater heat extraction, which helps shorten the investment recovery of the system. However, reducing the condensation temperature also decreases thermal efficiency of the CHP system. Moreover, there exists an optimal steam condensation temperature that minimizes the system’s levelized cost of electricity (LCOE). The heat extraction rate from the heat pipes declines rapidly in the first five years, and then gradually stabilizes. To maintain stable heat extraction over long term (30 years) and avoid interference between adjacent heat pipes, the center distance between any two heat pipes should be kept above 80 meters. The economic performance of the CHP system is closely related to the structural parameters of the heat pipes. At an optimal steam condensation temperature, increasing the heat pipe diameter and length, and selecting target zones with higher geothermal gradients can effectively reduce both the investment payback period and the LCOE.

Low-temperature adsorption technology for coal-fired flue gas pollutants can synergistically remove various pollutants and achieve near-zero emission. Focusing on the key equipment of this technology, flue gas spray cooling tower, ANSYS Fluent software is used to simulate the inside of the tower, and the impacts of various parameters are analyzed. The results indicate that, increasing the spray height effectively extends the contact time between flue gas and cooling water, thus significantly enhances heat exchange. Reducing the temperature of the cooling water strengthens the tower’s cooling capacity. Additionally, moderately reducing the inlet flue gas velocity increases its residence time in the tower, promoting more thorough heat exchange. Reducing the droplet diameter of the cooling water enhances the heat transfer efficiency by increasing the contact area. Enlarging the spray angle extends the residence time of cooling water within the tower and lengthens the contact duration with flue gas, boosting heat exchange. Increasing the cooling water flow rate expands the heat exchange area, further improving the heat transfer performance. The addition of packing material improves the heat exchange capacity of the tower while conserving cooling water. Comprehensively optimizing these parameters can substantially reduce the temperature of cooled flue gas, providing theoretical support for the design, manufacturing, and optimization of spray cooling towers in the low-temperature adsorption technology for coal-fired flue gas pollutants.

The formation and emission of SO₃ in coal-fired flue gas pose serious threats to both the safe and economical operation of power plants and the atmospheric environment. To solve this problem, the SO₃ removal performance of sodium-based, calcium-based and magnesium-based absorbents is investigated, and the performance variations of Na₂CO₃, Ca(OH)₂ and CaO under different operating conditions are studied. The results indicate that, under the coexistence of SO₂ and SO₃, the absorbers would react with SO₃ in the flue gas preferentially, and the effectiveness of SO₃ removal by various absorbents ranked from highest to lowest is as follows: Na₂CO₃>NaHCO₃>Mg(OH)₂>MgO>Ca(OH)₂>CaO. Under certain experimental conditions, the SO₃ removal efficiencies of all the absorbents could reach higher than 80% when the chemical equivalent ratio of absorbent to SO₂ reached 2:1. Pre-calcination treatment for the absorbents enhanced their pore structures, facilitating SO₃ diffusion into the absorbent and improving the SO₃ absorption efficiency. Increasing reaction temperature, chemical equivalent ratio, and initial SO₃ mass concentration can promote the SO₃ removal. Additionally, a moderate increase in H₂O volume fraction aided SO₃ removal. When the absorbent is significantly excessive, external diffusion is the main controlling step affecting the chemical reaction rate, while the type of absorbent has a relatively minor impact on it.

Effective monitoring of chloride ion indicators in precision treated effluent plays a crucial role in ensuring the quality of the effluent, adjusting operational processes, and extending operating cycles. According to the theory of ion exchange equilibrium, the operating characteristics, effluent quality, and resin regeneration requirements of hydrogen type and ammonium type operation modes for precision treatment were analyzed and compared. Through laboratory simulation experiments and tracking experiments of the operating cycle of a precision treated mixed bed in a certain power plant, the migration characteristics of chloride ions in the effluent of precision treatment were mainly studied. The results show that, the requirement for regeneration degree of resin in the hydrogen stage is low, and the main focus of this stage is desalination, which is not prone to chlorine leakage. As the pH value of the effluent increases during the conversion stage, the requirement for resin regeneration also increases. When the condensate contains chloride ions, chloride ion displacement is prone to occur. During ammonium type operation, the mixed bed no longer focuses on desalination, and the mass concentration of chloride ions in the effluent is equivalent to that in the condensate. Therefore, effective monitoring of chloride ions is necessary for ensuring the quality of effluent water, especially during ammonium type operation. At the same time, using chloride ions as one of the monitoring indicators can not only ensure the quality of effluent water effectively, but also guide the adjustment of precision treatment operation process, and significantly extend the precision treatment operation cycle while ensuring the safe operation of the unit.

To solve the problems of slagging and burner burnout caused by lean coal boilers which convert to firing Shenhua bituminous coal, a 600 MW supercritical opposed firing boiler was taken as the research object. Through thermal calculation and numerical simulation analysis, a feasibility study for the combustion system retrofit scheme was carried out with emphasis. The results show that, by adopting differentiated heat load design, inclined installation of side wall burners into the furnace, and multiple dimensions of wall mounted wind, the heat load in the burner area reduced from 1.71 MW/m² to 1.44 MW/m², and the flue gas temperature at the furnace outlet decreased from 1 058 ℃ to 1 010 ℃. The performance test results after the retrofit show that at rated load, the unburnt carbon content of coal ash decreased from 6.06% to 1.42%, the boiler efficiency increased from 92.76% to 94.03%, and the NOx emissions at the furnace outlet reduced by 50%~60% at various loads. The boiler can operate safely and efficiently for a long period. The proposed transformation technology scheme has guiding significance for the optimization and retrofit of combustion systems of similar units under the condition of converting low volatile coal to bituminous coal.