Superheated steam temperature is crucial for safety and economy of coal-fired power units. However, the large inertia and strong uncertainty of superheated steam temperature system make it difficult to control. To solve these difficulties, a cascade control structure based on modified active disturbance rejection control is proposed. The inner loop uses a conventional PI controller and the outer loop uses a modified active disturbance rejection controller. An engineering tuning method for modified active disturbance rejection control is provided, and a response curve to optimize the compensation time constant is designed to address the difficulty of obtaining the compensation time constant. Finally, the advantages of the proposed control strategy in tracking and disturbance rejection performance under large-scale variable loads are verified through comparative simulations and practical engineering applications. The operational data of engineering applications shows that the proposed method can ensure smaller maximum positive and negative deviations, average absolute deviation, and deviation standard deviation, which has significant advantages and potential for engineering applications.

With the rapid global industrialization and urbanization, ensuring continuous water supply and comprehensive water quality management has become a major challenge. Power plant cooling water consumption is significant, and to achieve zero discharge, many plants have adopted desalination measures to increase concentration ratios and enable water reuse. However, existing treatment technologies face high energy consumption, system complexity, and secondary pollution issues. To solve these problems, the application of electrochemical coupling pilot-scale equipment in cooling water treatment is experimentally studied, and the effects of electrochemical coupling pilot-scale equipment on scale removal, corrosion prevention and wastewater resource utilization are analyzed. The results show that, the equipment removes hardness and alkalinity significantly, and reduces conductivity and chloride ion content efficiently. Under conditions with voltage of 3.2 V and current of 240 A, the hardness removal rate reached the highest (5.15% and 55.77%, respectively), and under conditions with current of 250 A and voltage of 3.2 V, the alkalinity removal rate reached the highest (36.96% and 91.41%, respectively). The electrochemical coupling technology offers clear economic advantages compared with the conventional methods, providing an efficient, eco-friendly, and cost-effective solution for cooling water treatment with broad application prospects.

The growing share of renewable energy leads to increased load volatility and uncertainty in power system, necessitating greater flexibility in cogeneration systems. The utilization of molten salt thermal storage equipment can enhance the performance of cogeneration systems. Against the main-pipeline cogeneration system consisting of four boilers and two steam turbines which is integrated with a coupled molten salt thermal storage equipment, the EBSILON simulation software is used to establish mechanism model for power supply and heating. The influence of molten salt heat storage equipment on combined heat and power system performance is analyzed, and the optimization scheduling methods for coupled systems are also investigated. The results show that, the coupling of molten salt thermal storage equipment in cogeneration systems can increase the system’s peak shaving capacity, expand the system’s operating range, and broaden the unit’s operating area. After estimation, the amount of coal saved in one day can be about 4.16 tons, the carbon emissions can be reduced by about 8.25 tons, and the pollutant emissions can be decreased by about 1.76 kg. The molten salt thermal storage equipment has improved the system’s economy and environmental friendliness.

In order to build a large capacity flexible power supply and solve the dilemma of balancing winter peak shaving and heating for coal-fired units, six new “solar thermal storage” integrated power generation systems are proposed based on conventional thermal power plants (CFPP), utilizing solar energy and molten salt thermal storage to balance winter heating. The system is modeled using EBSLION software, and a comparative analysis is conducted on thermal performance and peak shaving performance of each scheme from the perspectives of thermal storage load and electricity load. The use of a “steam extraction + electric heating” thermal storage scheme significantly improves the peak shaving capability of thermal power units. Among the various schemes, Scheme W1 exhibits the maximum peak shaving depth of 92.71%, Scheme W6 shows a minimum comprehensive coal consumption of only 178.15 g/(kW·h), with a daily saving of 182 tons of standard coal. In addition, Scheme W2 achieves the highest cycle thermal efficiency of 55.2%. The use of the “light coal” storage scheme fully enhances the backup capacity of the supercritical carbon dioxide (S-CO₂) system, and the “extraction steam storage heat” drives the “small turbine” to assist the S-CO₂ system in heating, achieving the dual goal of peak shaving heating in winter. This type of system not only expands the peak shaving capacity of coal-fired units, ensuring heating for people’s livelihoods, but also fully utilizes solar energy resources, reduces coal consumption per kilowatt hour, and enhances the reserve capacity and power generation hours of S-CO₂ systems, providing theoretical and engineering guidance for the construction of high-capacity flexible regulation power sources.

In reheat and recompression cycle system, the high-pressure carbon dioxide fluid has high temperature at outlet of the high-temperature reheater, resulting in insufficient heat absorption of the working fluid entering the heat source heater. To solve this problem, the model of a supercritical carbon dioxide (S-CO₂) cycle photovoltaic coal complementary power generation system is established using Aspen Plus software. On the basis of the reheat-recompression cycle system, a novel dual-channel S-CO₂ cycle solar hybrid coal-fired power system is proposed. Moreover, the performance of the above two systems is analyzed and compared by applying the exergy analysis method. The results indicate that, the exergy efficiency of the new system can reach 40.578%, which is 3.494 percentage points higher than that of the reheat-recompression cycle system, and the exergy efficiency of the S-CO₂ cycle subsystem increases by 11.853 percentage points. The improvement of the exergy efficiency of the novel system can be attributed to the new path layout, which brings the third stage turbine to do work through full utilization of regenerative heat from the high temperature regenerator and reduces exergy losses from the main compressor and high temperature regenerator. Additionally, the contribution of solar energy in the new system is greater, resulting in an increase in output exergy from 9.846% to 10.059%.

In response to the current problems of high volatility in wind and photovoltaic power generation and difficulties in consumption in typical areas, a new hybrid energy system optimization scheduling method for promoting wind and solar consumption through geothermal power generation is proposed by incorporating reliable and rapidly climbing geothermal power generation into the hybrid energy system. Taking into account both operational costs and risks, and constrained by physical characteristics of the power units, a multi-objective optimization dispatch model for the new hybrid energy system is established. A rolling repair strategy is introduced to correct the initial values of the population, and the model is solved based on the adaptive trade-off model and the non-dominated sorting genetic algorithm II. This algorithm is more suitable for solving high-dimensional, complex constraint problems compared with the conventional algorithms and offers a faster convergence rate. Through a comparative analysis of two scenarios during typical winter days in a specific region of Tibet, geothermal power is found to enhance the absorption rates of wind and solar energy by 8.0% and 7.9%, respectively. Simultaneously, the system’s operating costs decreases by 2.5%, and risk indices decreases by 7.1%. These findings underscore the role of geothermal power in promoting the integration of wind and solar energy and improving the overall reliability of the power system. The research provides valuable theoretical support for decision-making and scheduling in hybrid energy systems.

Conventional energy storage systems have high investment costs, long payback periods, and cannot be applied on a large scale in park level systems. In response to this issue, an integrated energy system in the park is established firstly, which includes hybrid virtual energy storage such as electric vehicles, air conditioning, and heating network pipelines. Moreover, the operating mechanism of the system is also analyzed. Relevant models for system and virtual energy storage are constructed. Secondly, based on correction indicators such as peak valley difference and external grid interaction scale, a hybrid virtual energy storage incentive mechanism considering dynamic time of use prices is proposed. Then, under the carbon cycle mechanism of waste incineration cogeneration flue-gas treatment-P2G, a low-carbon operation optimization model for the integrated energy system in the park is constructed with the goal of maximizing profits. Finally, a case study is performed on an integrated energy system in a certain region, and the results show that, operation optimization considering hybrid virtual energy storage can reduce external grid interaction costs. A hybrid virtual energy storage incentive mechanism considering dynamic time-sharing prices can improve the enthusiasm of virtual energy storage entities to respond to system scheduling. Considering the carbon cycle mechanism of waste incineration cogeneration flue-gas treatment-P2G can increase net revenue.

An axial tangentially swirl low nitrogen burner is designed based on flue gas internal circulation and staged combustion, and the effects of the burner’s load, fuel staging, and recycled high-temperature flue gas on combustion and NO_x emission characteristics are studied through industrial experiments and numerical simulations. The results indicate that, the loads and fuel staging ratios have a synergistic effect on NO_x generation. Under medium and low load conditions, the NO_x emissions increase monotonically with the secondary fuel ratio, large amount of NO_x generates in the secondary flame zone. At full load, there exists an optimal primary to secondary fuel ratio (88:12), which minimizes the NO_x emissions. When the secondary fuel ratio falls below 12%, the primary flame zone becomes dominant in NO_x production. The length of the primary fuel mixing pipe can alter the fuel and air mixing process, thereby affecting NO_x generation. When the relative length of primary fuel mixing pipe is shortened to 0.74, the main combustion zone moves upstream in the furnace, and the main flame is anchored in the middle of the furnace, resulting in a more uniform temperature distribution at the rear of the furnace. The NO_x emission mass concentration decreases by 10%~20% across all loads, all below 30 mg/m³ (with O₂ volume fraction of 3.5%, the NO_x is calculated as NO₂).

To ensure the continuously stable operation of adiabatic isothermal-compressed air energy storage system, an adiabatic-isothermal compressed air energy storage method coupled with buffer tank is proposed. The dynamic thermodynamic model of the buffer tank coupled system is established, and the experimental platform is set up to verify the model. Besides, the variation mechanism of air temperature and pressure in the buffer tank is revealed, and the influence of design parameters of buffer tank on system performance is explored. The results show that, the adiabatic-isothermal compressed air energy storage system with buffer tank exhibits favorable isotherm, and the highest temperature difference at 30 K during the cycle. The adiabatic efficiency of the compressor unit of the coupled buffer tank system increased by 8 percentage points, and the exergy loss of the compressor unit decreased. Sensitivity analysis shows that the change of energy storage power has little effect on thermodynamic parameters of the air storage room, and the volume of the buffer tank decreases with the increase of energy storage power. Moreover, the change of energy storage scale has little influence on thermodynamic parameters of the air storage room, and the change trend of air temperature shows a periodic fluctuation. When the system energy storage scale increases, the volume of buffer tank will increase with the energy storage scale. The study provides a novel scheme for the continuous, stable and efficient operation of adiabatic-isothermal compressed air energy storage system.

Organic Rankine cycle (ORC) power systems can convert low-temperature (<150 ℃) thermal energy into mechanical energy to generate electricity. To improve the performance of small-scale ORC power systems, an ORC test-rig was built, which has a scroll expander directly connected to the generator. With a 24 kW variable-temperature heat source and the work fluid R245fa, the effects of the variations of load resistance (50~200 Ω) and the heat source temperatures (75~95 ℃) on the performance of the ORC test-rig were explored. The results indicate that, both the output shaft work and the thermal efficiency initially increase and then decrease with rising the load resistance. An optimal load resistance exists to maximize either the output shaft work or thermal efficiency, and this value varies with the heat source temperature. When the heat source temperature is 95 ℃, the output shaft work and thermal efficiency both reach the maximum at 100 Ω load resistance value, which is 722 W and 2.30%. When the heat source temperature is 75 ℃, the output shaft work reaches the maximum at 200 Ω load resistance, which is 532 W, but the thermal efficiency reaches the maximum at 150 Ω load resistance, which is 1.7%. The variation of the resistive load or the heat source temperature can change the scroll expander rotation speed and thus affect system flow rate. Therefore, the simultaneous changes of the resistance load and the heat source temperature have a synergistic effect on the system performance. The results highlight the importance of matching the resistance load and the heat source temperature. The experimental data also provide a direction for optimizing the ORC power systems.