Chemical absorption method is an effective way to capture CO₂ from flue gas of coal burning. Compared with conventional organic amine absorbents, two-phase absorbent can significantly reduce the regenerative energy consumption and the capture cost. A new type of two-phase sorbent is developed, which uses the physical solvent diethylene glycol dimethyl ether as split-phase agent, ethanolamine and hydroxyethyl ethylenediamine as the main agent, and its absorption regeneration performance, viscosity, water phase proportion and phase separation interval is tested. Moreover, nuclear magnetic resonance (NMR) spectroscopy is carried out for the two phases in the sorbent to determine the composition and phase splitting mechanism. The organic amine composition in the formulation is optimized, and the results show that, the absorption and regeneration performance of the optimized absorbent is better than that of the conventional 5 mol/L ethanolamine absorbent. The cyclic absorption capacity can reach 2.086 mol/kg, more than 99% of CO₂ is enriched in water phase, and the flow of the absorbent entering into the regenerator can be reduced by about 40%. The viscosity of the water-rich phase is lower than 10 mPa∙s, the theoretical regeneration energy consumption is 2.688 GJ/t (calculated in CO₂), indicating the new two-phase sorbent has a good industrial application prospect.

The implementation of carbon pricing policy will have an important impact on the low-carbon transformation of power industry. This paper constructs a power dynamic stochastic general equilibrium (DSGE) model with carbon pricing policy, and systematically investigates the different impacts of carbon trading and carbon tax on emission reduction of the power industry under the goal of carbon emission peak and carbon neutrality. The results show that, the overall impact of carbon trading policy is greater than that of carbon tax policy, and the impact of carbon trading policy on emission reduction is achieved by inhibiting thermal power output under the carbon peak scenario, while it is achieved by encouraging green power output under the carbon neutral scenario. Different mechanism designs of carbon pricing policies, such as carbon trading and carbon tax, will have different impacts on emission reduction in the power industry under the dual carbon target. In the carbon trading policy, especially in the carbon peak scenario, there is a certain upper limit to achieve emission reduction through the market mechanism, and when the upper limit is exceeded, a "back-forcing" mechanism will be formed. In the carbon tax policy, the rebate mechanism will achieve the goal of emission reduction and the expansion of the rebate proportion will strengthen the impact on electricity emission reduction. Based on the above conclusions, relevant policy recommendations are put forward.

Based on the elastic beam theory, a theoretical calculation model for the axial force of the in-service tie rod under transverse loading conditions and the three-dimensional finite element model of the prestressed beam are established. The axial force measurement method of the tie rod of the in-service support hanger is studied, and the influence of different length-to-diameter ratios and transverse loads on the deflection of the midpoint for the tie rod are discussed. The results show that the theoretical prediction results are in good agreement with the finite element calculation results. In terms of engineering applications, an optimal scheme for the length-diameter ratio of the fixed support section of the tie rod is given based on the transverse load tolerance and deflection tolerance value. This method can be used to quickly measure axial load of tie rod when it is not uninstalled.

The internal flow and temperature rise characteristics in the last stage of steam turbine low pressure cylinder under low flow rate condition is quite complex, which makes thermal power peak load regulation and cut-off transformation more challenging. By taking the low pressure cylinder of a steam turbine in a power plant as the research object, a five-stage cascade single-channel calculation model of the low pressure cylinder was established, and the working performance, flow structure and temperature rise characteristics of the low-pressure cylinder under different working conditions were numerically investigated. The research shows that, when the flow rate of the low-pressure cylinder decreases to 3.84% of the design condition, the low-pressure cylinder outputs no positive power. When the flow rate is quite low, the low pressure cylinder enters the windage condition, and the flow structures such as the hub endwall separation area, the vane separation area, the casing torus vortex, and the last stage bucket vortex appear in the last stage cascade, by concomitant of obvious windage heating effect at the tip position of rotor-stator clearance area of last stage cascade under low flow rate condition. When the flow rate decreases to 2.23% of the design condition, the average surface temperatures of the last stage vane and blade increase by 219.6 K and 243.7 K, respectively. The working performance and internal flow structure significantly change under windage condition. The temperature rise in the last stage cascade deteriorates the working environment of the blades, which needs to be taken into consideration when the steam turbine works under low flow rate condition.

In order to effectively deal with the complex electricity and coal market, strengthening the smart fuel management has become an important part of thermal power plant management. Aiming at solving the problems that the coal yard of a coal-fired power station occupies small area, the types of incoming coal are complex, and the coal-fired coal stacking is chaotic, by extracting the coal quality information of historical incoming coal, K-means and DBSCAN clustering algorithms are used to analyze the low-level coal. The calorific value, volatile matter and sulfur content are clustered and analyzed, and the two clustering algorithms are compared from the perspective of silhouette coefficient, cluster stability and sample division fineness, and finally K-means with better clustering effect is selected as the calculation method for coal quality division. The K-means algorithm divides the selected historical coal quality information data set into four categories, the contour coefficient is 0.587, and the coal quality components in each category are similar. The incoming coal frequency and the incoming coal weight ratio under different cluster labels are counted, and the coal yard is divided into corresponding proportions. The incoming coal of the same classification is stacked in each partition, and on this basis, the incoming coal in the digital coal yard platform is designed. Coal stacking guidance and information storage process are of great significance to improving the utilization of storage yard space and the efficiency of coal yard management.

To study the effect of decarbonization on thermal power units, a simulation model is established to analyze the performance changes of the conventional scheme of carbon capture retrofitting in thermal power units. Moreover, a zero-output scheme of a low-pressure turbine is further proposed to improve the flexibility of the units. The conventional method uses the exhaust steam of the intermediate-pressure cylinder as the reboiler heat source, and the zero-output scheme of the low-pressure cylinder cuts off the low-pressure cylinder inlet steam. On one hand, the two methods are analyzed separately by taking a 300 MW coal-fired power unit as an example. On the other hand, the effects of the two schemes on thermal power units of the whole province is predicted by taking a province in northwest China as a research object. The results show that, the unit output range under the conventional scheme is reduced from 87~300 MW to 147~217 MW, and the power supply efficiency under rated operating conditions decreases from 37.32% to 27.02%. The minimum unit load ratio increases to about 70%. The unit load range ise widened to 47~217 MW when the zero output scheme of the low-pressure cylinder is adopted, which is 2.44 times of that of the conventional scheme. For the discussed northwestern province, the thermal power output range is reduced from 1 103~3 940 MW to 1 875~2 793 MW under the conventional scheme, and the output range is widened to 550~2 793 MW under the low-pressure cylinder zero output scheme.

Measuring the investment value and investment timing accurately is crucial for coal-fired power plants' carbon capture utilization and storage (CCUS) investment. Different from the existing studies on the CCUS decision making only considering the integration mode, this study establishes the decision-making model of the CCUS investment of coal-fired power plants under the integration mode and joint venture mode from the perspective of coal-fired power plants. The decision-making model is established based on the theory of real options, considering the uncertainties of carbon price and the decreasing CCUS investment cost, and the displayed solutions of the option value and investment timing of CCUS investment in coal-fired power plants under different modes are obtained by solving the model. Based on this model, the impact of different policy incentives such as additional power quota, electricity price subsidy, investment subsidy, and carbon price volatility on CCUS investment decisions are further analyzed through numerical examples. On this basis, some policy suggestions are provided finally.

In recent years, the scale of wind power is growing rapidly, its economic analysis and cost modeling methods are also constantly improving. In order to summarize the existing methods and clarify the follow-up research ideas, the four stages of the whole life cycle of the wind power project are first explained. Then, the cost composition and modeling method of the whole life cycle of wind power projects are introduced, and the differences between onshore and offshore wind farms in this part are compared, and the relationship between life cycle and investment cost is discussed based on the above contents. In order to introduce the benefits of cost investment, the basic economic evaluation indexes and applicability of wind power projects are compared. On this basis, the future development trend is analyzed according to the existing problems, and some suggestions are put forward for the economic evaluation of wind power in different regions and environments. It is hoped that the work of this paper can provide reference for wind power cost modeling and economic evaluation under the new development trend.

Aiming at solving the problems of large number of wind turbine faults, complex fault knowledge relationship, large difference of knowledge expression and low efficiency of knowledge reasoning, a framework of acquisition, expression and reasoning of wind turbine fault knowledge is proposed. Firstly, through the failure mode and effect analysis method based on the fault tree analysis method, the expert knowledge of wind turbine trouble shooting and maintenance is comprehensively obtained and sorted out. Then, with the help of ontology theory, unstructured expert knowledge is expressed structurally to form a knowledge map and displayed visually. Combined with self-defined rules of ontology and causal reasoning model, the query and reasoning of fault causes are realized, which improves the efficiency of knowledge query and reasoning. Finally, the practicability of this method is illustrated by a specific unit fault case. The results of this study can provide a direction for the intelligent development of wind farm's operation and maintenance.

The wake effect of wind farm is the main factor affecting the performance of wind turbines in the downstream wind farm. The wake effect, load characteristics and fatigue damage of wind turbines in front, middle and rear of an offshore wind farm were quantitatively assessed by FAST.Farm, which is the latest opensource multi-physical field coupling simulation software tool of National Renewable Energy Laboratory (NREL). The results show that, the wind speed decreases and the turbulence intensity increases in turn in the wind farm along the flow direction. The fatigue damage of front-row, middle-row and back-row wind turbines increases with the inflow wind speed. Especially, under the condition of high inflow wind speed, the fatigue damage of the middle-row wind turbines at the blade root and the tower base increases exponentially, and the increase range is obviously higher than that of the front and back row wind turbine. It suggests that the structural strength of wind turbines in the central area should be improved to some extent in wind power pre-development and post-operation and maintenance work.