To improve the load response rate of coal-fired units, a dynamic process model was established for a 600 MW supercritical coal-fired unit through using the Modelon component library in Dymola software, while the influence of replacing steam extraction for feedwater heating by high-temperature molten salt on the dynamic characteristics of key parameters in the coal-fired unit was researched. Research results show that, compared with replacing the high-pressure heaters, the method of replacing the low-pressure heaters has a less influence on the unit parameters of main steam, reheat steam, feedwater, and the response performance of unit load decreases with the decrease of unit load. When replacing the high-pressure heaters by high-temperature molten, following effects were obtained, such as the longer load response time, the higher load variation, and the lower average rate of load change, while the reverse effects were obtained when replacing the low-pressure heaters by high-temperature molten salt. Additionally, the thermal-to-electric conversion efficiency with the high-pressure heaters replaced by molten salt is higher than that with the low-pressure heaters replaced by molten salt.

The technology of feed water pump directly driven by steam turbine main shaft is a new drive technology for feed water pump, and at present there is no mature operating experience about it in China. A series of simulation tests of a 350 MW direct air cooling unit adopting this technology under off-design conditions had been conducted. Results show that, for unit equipped with one 100% capacity main pump and one 50% capacity stand by pump, the technology can fully meet the needs of the feed water flow under the working conditions of rapid change of unit back pressure, load change and feed water pump fault.

By taking the section of the turbine from the main stop valve to the first extraction point as an equivalent steam distribution stage, characteristic curves for the stage under various total valve position commands were established, so as to realize the calculation of turbine steam distribution characteristics with the total valve position command information under off-design condition. It has been verified the simplified simulation calculation using the equivalent steam distribution stage closely aligns with the comprehensive simulation calculation of the steam distribution. The method computationally convenient, matches the actual characteristics of the experimental unit, and satisfies the requirements for engineering application.

Brush seal has a good effect on sealing, therefore, it has been widely used in the field of heavy gas turbine. Experimental studies were carried out for the leakage characteristics of brush seal in gas turbines, the sealing effects of brush seal under different clearance conditions were compared and analyzed. Results show that, under a certain experimental condition, the flow coefficient of brush seal, decreases slightly with the increase of pressure ratio, decreases slightly with the increase of rotor speed, and decreases with the decrease of seal clearance. Moreover, when the seal clearance is less than the critical seal clearance, the sealing effect of brush seal is better than that of labyrinth seal. Experimental results can serve as a meaningful reference for the design and application of brush seal in gas turbines.

To optimize the flue gas flow field of a vertical waste heat boiler, a numerical simulation was conducted on the flue gas flow field with the standard κ-ε double-equation turbulence model based on ANSYS software, while the influence of the bottom plate arrangement type of inlet flue gas duct on flow field was researched. After which, the velocity distribution of the outlet end face of inlet flue gas duct with different bottom plate arrangement types was obtained, and quantitative analyses were carried out for simulation results through using the velocity uniformity index. Results show that, the flow field uniformity of the bottom plate arrangement with 45° inclination angle is superior to that with 0° and 23° inclination angle. Simulation results can serve as a reference for the bottom plate arrangement of inlet flue gas duct in vertical waste heat boilers.

According to the actual situation of a mountain photovoltaic power station, the fixed support type was optimized. Under the premise of meeting the requirements of the design specification, the amount of steel used in the photovoltaic module support is effectively controlled, which has better economic benefits. At the same time, analyses were conducted according to the distribution characteristics of slope, so as to ensure the adaptability of the module under different mountain slopes. The results have an important reference significance for the optimal design of mountain photovoltaic power stations, the improvement of construction progress and the reduction of construction costs.

By means of macroscopic inspection, geometrical dimension measurement, chemical composition analysis, mechanical property testing and metallographic structure analysis, analyses were conducted on the bulge deformation reason of the water wall tube panel of a 350 MW supercritical boiler in a power plant. Results show that, the bugle deformation problem is related to the local thermal recalibration process during the field installation of water wall. The size deviation of tube panel with bulge deformation is small, while the hardness of bulge tube is lower than that in the heat affected zone of bare tube and flat steel. Besides, there is no abnormal metallographic structure in the sampled tube with bugle deformation. Moreover, the strength in bugle deformation position is slightly higher than that in normal position, and the bugle deformation position is not yet a weak link during the use of tube material. There is no significant effect on the normal use of tube panel with bugle deformation caused by thermal recalibration.

With a well corrosion resistance to seawater, high density polyethylene (HDPE) has been gradually applied in service water system or some equipment cooling water system with nuclear safety class 3 piping system requirements in pressurized water reactor nuclear power plants. In order to effectively improve the quality of HDPE piping fusion-jointing procedure, according to ASME BPVC standards, analyses were conducted on the material properties, fusion-jointing procedure qualification and practice of HDPE piping system with nuclear safety class 3. The quality of HDPE piping fusion-jointing procedure can be significantly improved through appropriately controlling following parameters, such as the fusion-jointing pressure during formation and cooling down, the end face pressure during continual heating, the requested pressurization and heating time of end face, and the shortest requested time of continual heating.

Based on a case of the welding and plugging of steam generator heat transfer tube of a pressurized water reactor in a nuclear power plant, in accordance with the 2021 edition of ASME BPVC, analyses were conducted from the aspects of plugging head material, welding material, welding procedure qualification, and plugging procedure techniques, so as to ensure the effectiveness of the tube welding and plugging procedure. Through using a qualified tube plugging procedure, the damaged heat transfer tube of steam generator in the nuclear power plant was plugged. There is no leakage occurring in steam generator after plugging during normal operation, which demonstrates the successful effectiveness of the tube plugging. The results provide technical references for the welding and plugging procedure of steam generator heat transfer tube after damage in domestic nuclear power plants.

Based on an introduction on corresponding criterions for the regulation accuracy assessment of automatic generation control (AGC) of Jiangsu province power grid, the AGC regulation accuracy assessment was researched for a 660 MW ultra supercritical double reheat unit, and analyses were conducted on the reason of AGC regulation accuracy assessment of the unit. After which, following measures were proposed for the optimization of AGC regulation accuracy assessment, such as adjusting the main steam pressure with heat-supply load, and improving the unit load changing rate with AGC. Through taking above measures, the effect of the unit load tracking the AGC instruction is good, while the AGC regulation accuracy is improved significantly. This can significantly improve the economy of unit operation and the stability of power gird.

In two 1 000 MW coal-fired coupled sludge generator sets of a thermal power plant, the plate and pole line of the electrostatic precipitator were covered by ash deposition, which was seriously corroded and the service life was shortened. The corrosion mechanism and causes were analyzed by detecting the ash deposition and corrosion products on the plate and pole line, combined with the sludge blending and equipment operation investigation. Results show that, after the unit is mixed with sludge, serious ash deposition and wear of denitration catalyst lead to high ammonia escap erate. Strong acidic salts such as ammonium bisulfate and ammonium sulphate generated by ammonia escape are viscous deposition on the surface of the plate and pole line, which absorbs moisture and then deliquescent, forming a strong acidic electrochemical corrosion environment and causing serious corrosion of metals. The alkali metal and chlorine content of the coal into the furnace are high, and the granular chlorate is deposited on the plate and pole line with the viscous ash, which aggravates electrochemical corrosion.

To solve the problem that the power consumption rate of the condensate pump in an ultra-supercritical 600 MW unit is higher than that in similar units, analyses were conducted on the reason of the high pressure loss of flushing water pipeline for mechanical seal in the booster pump, and combined with theoretical calculation, following measures were proposed, such as changing the internal component of control valve for mechanical seal flushing water, removing the second stage impeller of the condensate pump, and optimizing the control logic of the frequency conversion of the condensate pump. Practical results show that, without increasing the complexity of this system, the outlet pressure of the condensate pump decreases by 0.24-0.54 MPa, the electric current of the condensate pump decreases by 10-21 A, and the power consumption rate of the condensate pump decreases from 0.2% to 0.15%.

Water hammer poses a serious threat to the safe and stable operation of power plant. The mechanism of water hammer was analyzed. According to the typical water hammer phenomenon of a gas turbine power plant, the causes of water hammer in several operating equipment and systems were described. The occurrence of water hammer is reduced or avoided by operation technology optimization and equipment management.