To investigate the potential of carbon emission monitoring technology in optimizing thermal power unit operations beyond the “double control” of emissions in thermal power enterprises, an F-class gas-steam combined cycle unit where a CO₂ monitoring system is installed at the tail chimney is selected to be discussed. Research is conducted using online fuel monitoring data from the front pressure regulating station and flue gas monitoring data from the rear chimney environmental protection measurement point. The results reveal that, in the high-load section, the flue gas monitoring carbon emission rate is consistently higher than the fuel monitoring rate, although both curves exhibit similar trends, indicating comparable yet offsetting data. For units operating at medium loads, atmospheric conditions are crucial. Elevated temperatures may increase heat loss, while reduced air pressure can minimize compressor energy consumption, thereby decreasing the unit’s instantaneous carbon emission intensity. Among various parameters, adjusting the turbine expansion ratio, compressor pressure ratio, and steam fuel power ratio could be effective strategies to minimize carbon emissions without altering the unit load.

The microwave attenuation method is one of the common methods for online measurement of carbon content in fly ash in recent years. However, due to the differences in sampling locations and sampling devices of the fly ash, there is a large uncertainty in particle size of the fly ash, which results in a large error in the measurement of carbon content in fly ash. The existing carbon content fitting models are all based on the relationship between the attenuation of the characteristic frequency signal by fly ash and the carbon content of fly ash, which has problems such as large error and poor adaptability. In order to solve these problems, this paper proposes to use the time-domain main peak attenuation of the signal instead of the attenuation of the signal at the eigenfrequency as a method for online fitting of the carbon content in fly ash. To correct the error caused by the uncertainty of fly ash particle size, the effects of fly ash with different particle size ranges on the measurement of ash level and fly ash carbon content are compared on the basis of the study on ash level and carbon content measurement. The results show that, the peak attenuation of the signal in the time domain is used to calculate the carbon content, and the results are in good agreement with the actual values. For the same mass of ash samples in the waveguide, the particle size of the fly ash does not have any significant effect on the measurement accuracy of the ash level. When the microwave method is applied to measure the carbon content in the fly ash in the waveguide, for the same mass of ash samples, the attenuation of the fly ash on the microwave signal inside the waveguide decreases gradually with the particle size of the fly ash. Thus, the measured value of carbon content increases as the particle size of the fly ash decreases.

ZnFe₂O₄ oxygen carrier (OC) doped with different additives (Sr, Ce, La and Al) was prepared by sol-gel method to investigate the influence of different additives on performance of the ZnFe₂O₄ oxygen carrier. Chemical looping hydrogen generation (CLHG) experiments were carried out in a fixed bed reactor. It was found that the performance of ZnFe₂O₄ was greatly improved by doping different metals, and the hydrogen production of per unit mass OC from high to low is La>Sr>Al>Ce. The physicochemical properties of different amount of La-doped ZnFe₂O₄ were further analyzed by combining X-ray diffraction, H₂-temperature-programmed reduction, Brunauer-Em-mett-Teller method and other characterization methods. The data indicated that the ZnFe₂O₄ modified by La with 12% mass fraction has the highest reaction activity. La dropping can increase the specific surface area of the OC, reduce the reduction temperature, increase the migration rate of lattice oxygen, promote the formation of oxygen vacancies, and is beneficial to the increase in hydrogen production in the chemical looping process.

In order to explore the film cooling potential of crater holes, numerical simulations are performed to investigate the film cooling characteristics of equal-section crater hole, concentric elliptical crater hole, and two types of rounded corner crater holes proposed on the basis of these two types of crater holes. Cooling efficiency curves are analyzed for four types of crater holes at blowing ratios of 0.5, 1.0 and 1.5. The results show that, the crater spreading width of crater holes and crater film holes with rounded corners increases, which is beneficial to spreading coverage of the cooling film. After the crater holes are rounded at three blowing ratios, the Coanda effect strengthenes the ability of the cooling jet to adhere to the wall, and the film cooling efficiency in the near-hole region improves significantly. As the blowing ratio increases, the area-averaged film cooling efficiency after the rounded corner treatment increases by 76%, 139% and 155%, respectively, for the equal-section crater hole. The area-averaged film cooling efficiency improves by 18%, 27%, and 29%, respectively, for the concentric-elliptical crater hole with rounded corner compared with that of the concentric-elliptical crater hole.

Solar power plants can be complementary to other new energy power generation stations, and can also undertake the task of peak modulation and frequency modulation of power grid, which have attracted more and more attentions. In this paper, the dynamic simulation model of thermal storage system and power generation system is built and verified by Apros software. The coordinated control system of solar power plant considering the influence of heat storage is designed, and the maximum variable load rate of the solar power plant in different load intervals is studied. The results show that the proposed coordinated control strategy has a good control effect. Compared with the control without heat storage control, the deviation of main steam pressure with heat storage control reduces from 0.17 MPa to 0.07 MPa. Under the set limit conditions, the maximum load rise rate of 100%THA~75%THA load interval is 11.57%/min, and the maximum load reduction rate is 8.94%/min. The results can provide reference for peak shaving and frequency modulation operation of photothermal power plants.

Transformer insulating oil will gradually deteriorate during the operation of power equipment, resulting in a significant reduction in the electrical, physical and chemical properties of transformer oil. In this paper, the adsorption phase reaction technology is used to solidify hydrophilic SiO₂ nanoparticles on microcrystalline cellulose (MCC), to prepare modified cellulose dust collector materials with high adsorption performance, to purify and treat dirty transformer oil by combining with electrostatic adsorption technology. For the SiO₂ modified cellulose dust collector material, it can be concluded through the oil purification effect test that, the best preparation condition is dissolution and drying for 12 h, and adding 6 g ethyl orthosilicate (TEOS) as a silicon source. Then, the modified cellulose dust collector material prepared above conditions is placed in the electrostatic oil purification reactor. After synergistically purified by the two methods, the transformer oil’s main operational indicators such as moisture reduces from 32.0 mg/L (the initial value) to 23.5 mg/L or less, and other key indexes including medium loss factor, acid value and volume resistivity have reached the national standard of operational oil. It shows that the electrostatic technology combined with modified cellulose adsorbent material can effectively adsorb the impurity particles in the oil.

In order to solve the problem of low accuracy of wind power prediction caused by wind speed uncertainty and volatility, this paper proposes a VMD-ISSA-GRU combination model based on variational mode decomposition (VMD), improved sparrow search algorithm (ISSA) and gated recurrent neural network (GRU). Firstly, the center frequency method is used to determine the number of modal components after VMD decomposition, which can effectively avoid over-decomposition or insufficient decomposition. Then, chaotic mapping, nonlinear decreasing weights and a mutation strategy are introduced to improve the sparrow search algorithm to optimize the gated recurrent neural network, and then an ISSA-GRU prediction model is established for each decomposed subsequence. Finally, the predicted value of each subseries is superimposed and the final predicted value is obtained. The experimental results show that, the mean absolute error, mean absolute percentage error and root mean square error of the VMD-ISSA-GRU model are 1.211 8, 1.890 0 and 1.591 6 MW, respectively. Compared with the conventional GRU, long short-term memory (LSTM) neural network, Bi-directional LSTM (BiLSTM) neural network model and other combination models, the prediction accuracy has been significantly improved, which can solve the problem of low prediction accuracy of wind power.

Due to the characteristics of the medium transported by medium speed coal mill and the limitations of the inlet pipeline and space, the testing method under cold pure air conditions cannot guarantee the timeliness of the calibration test for the inlet air volume. Under hot conditions, the outlet pipeline of the coal mill was selected as test object for its stable flow field. The dynamic pressure and pulverized coal distribution characteristics of each powder pipe were tested by the equal cross-section grid method. The flow velocity of the air-powder mixture was obtained by the cyclic iterative method. Finally, the inlet air volume of the coal mill was compared and calibrated by the difference between the measured air-powder mixture flow rate, the coal quantity and the design sealing air volume. The practical results show that, on the basis of the same measured original data, the inlet flow rate obtained by the method above is closer to the real value, the accuracy can be improved by about 15 percentage points compared with the calculation results with cold conditions method. This method is simple to test and practical, which can effectively improve the timeliness and accuracy of the inlet air volume calibration results of medium-speed coal mill under hot conditions, and at the same time, it also has a certain guiding role in test of the flow rate of powder-containing gas in similar industrial environments.

To solve the problems of fouling, slagging, and high-temperature corrosion in an ultra supercritical 1 000 MW unit boiler fueled by Zhundong coal, engineering verification test of nano-high-entropy ceramic coating in separated over fire air (SOFA) area of the boiler rear water wall was carried out, based on the coal characteristics, slagging condition and corrosion type of the boiler. Several methods such as macrographic check, scanning electron microscope (SEM), X-ray diffraction (XRD), Raman spectrum, friction coefficient and surface energy test were applied to observe the change of nano-high-entropy ceramic coating before and after experiments, thus to reveal the possible slag resistance and corrosion resistance mechanisms of nano-high-entropy ceramic coating. The results show that, the coating remained intact after 11 months’ boiler operation, with no obvious slagging and corrosion pits on the surface and no significantly thinning of the pipe wall. Nano-high-entropy ceramic coating can better solve the problems of fouling, slagging and high-temperature corrosion on the boiler water wall, which provides a guarantee for safe operation of the boiler fueled by Zhundong coal.

It is difficult to control NO_x emissions during full load operation of a 660 MW supercritical circulating fluidized bed (CFB) boiler in a certain power plant, and its instantaneous value is prone to exceed the ultra-low emission limit. In addition, the selective non-catalytic reduction (SNCR) system has a high ammonia consumption and severe ammonia escape issues. To solve these problems, on-site experiments on NO_x original emissions, SNCR denitrification efficiency, CO mass concentration and bottom slag combustibles were conducted, and optimization experiments on secondary air volume layout were also performed. It was found that, the original NO_x emissions of the CFB boiler were relatively low, with a maximum of 120 mg/m³ (standard condition) during full load operation and a NO_x mass concentration below 50 mg/m³ during medium and low loads. However, there was a significant deviation in NO_x mass concentration between the front and rear ends of the furnace, and the NO_x in flue gas was mainly generated in front of the furnace. The reason why NO_x emissions are difficult to control is due to the low denitrification efficiency of SNCR and uneven coal feeding in the furnace. The SNCR denitrification efficiency at inlet of the 6 separators was all below 50%, among which the denitrification efficiency of four separators B, C, E, and F was below 40%. Furthermore, according to the distribution of parameters in the furnace depth direction, such as the bed temperature, the content of combustible materials in bottom slag, and the variation of CO mass concentration, it can be determined that the uniformity of coal feeding in the furnace also had a significant effect on the control of NO_x emissions at full load. Currently, the power plant cannot achieve uniform coal feeding without renovation, but the original NO_x generation can be reduced by adjusting the secondary air volume ratio in the depth direction of the furnace, with a reduction of up to 9.77%.