In the context of Europe's vision of achieving carbon neutrality by 2050, carbon capture, utilization and storage (CCUS) technology, as an important means to achieve carbon emission reduction goals, has embraced a major development opportunity. This paper summarizes the development status of CCUS in Europe, including the financial incentive policies, carbon tax and policies, laws and regulations, and technology innovation policy for the development of CCUS technology in Europe, and the challenges in the process of developing CCUS technology in Europe, including the implementation of public funds, the comprehensive development of CCUS policies, and clear definition of responsibilities for CCUS projects. It points out that up to now, the development of CCUS technology in Europe is relatively mature. Relevant laws and regulations, financial incentives, tax support policies, and technology innovation policies have come into effect. Bioenergy with carbon capture and storage (BECCS) and direct air capture with carbon storage (DACCS) are important means to achieve negative emissions in the future. CO₂ industrial clusters and the development of transportation network can greatly reduce the transportation cost of CO₂, create profits at scale, and thus promote the application of CCUS. In 2020, China made the pledge to achieve carbon peaking by 2030 and achieve carbon neutrality by 2060. Combining the development status and relevant policies of European CCUS with basic national conditions of China, it puts forward the urgent need for current development of CCUS technology in China, and the problems that need to be solved.

Under the policy of peak shaving and carbon trading, cogeneration units face a more complex background. In order to obtain the carbon emission characteristics, income distribution and carbon trading economy of the traditional extraction condensing cogeneration unit under all operating conditions, and provide a reference for the unit to deal with carbon market fluctuations when participating in carbon trading. Using EBSILON simulation software combined with python program, the carbon emission distribution and income composition of the unit under all operating conditions are obtained. The research results show that the carbon emission kilowatt hour is inversely proportional to the load. Taking 325 MW and 150 MW as examples, the carbon emission intensity of power supply increases from 903.54 g/(kW·h) to 1 015.28 g/(kW·h), and the total carbon emission is proportional to the load; The highest proportion of peak shaving income can reach 55%; The highest proportion of carbon trading income can reach 8%, and the peak shaving income accounts for a large proportion in the low load, while the carbon trading income accounts for a large proportion in the high load. Comparing the change of carbon price from 40 yuan/t to 90 yuan/t and the change of power supply carbon emission standard from 0.9 times to 1.3 times, it is found that the change of power supply carbon emission standard has a greater impact on the proportion of carbon trading income. The formulation of power supply carbon emission standard should be combined with the unit emission level. Too high or too low will affect the enthusiasm of cogeneration power plants to participate in carbon trading.

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.

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.

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.

Against the difficulty of optimal scheduling of integrated energy systems under the operating conditions of multiple energy complementary mechanisms, a multi-objective optimal scheduling study is carried out considering the reduction of system operation and maintenance costs, carbon dioxide emission and renewable energy abandonment. A mathematical model is established for all the equipments in the electric-gas-heat-cold energy system. The constraint conditions that can simulate the long-term operation scheduling of the integrated energy system are established to solve the modeling difficulties of energy storage equipment in the long-term operation simulation, and the comprehensive energy system is optimized by using low-carbon economic operation index. The results of the minimum operation cost scheduling and the minimum carbon emission scheduling are compared. Moreover, the influence of carbon price and operation and maintenance cost increase on scheduling results is simulated. The simulation results show that, using only the minimum operation and maintenance cost or the lowest carbon emission as the scheduling index will lead to high carbon emission or high operation and maintenance cost, and the low-carbon economic scheduling considering the consumption of renewable energy and carbon emission reduction index can reduce the low-carbon economic operation cost of the whole system.

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 order to clarify the dynamic characteristics of bed temperature of biomass circulating fluidized bed (CFB) boiler, so as to establish a CFB combustion control system which is more suitable for biomass, a dynamic bed temperature model is established by analyzing the biomass combustion process and combustion mechanism. On the basis of the theory of instant burning carbon combustion, the correlation degree of temperature field in the furnace is calculated and analyzed. The results show that, the calculated bed temperature can be controlled basically stable near the filtering value of the actual bed temperature, and the variation trend of the bed temperature is similar to that of the actual filter bed temperature, which verifies the adaptability and effectiveness of the model. The temperature correlation difference of the upper and lower parts of the biomass CFB boiler is related to the oxygen content and the temperature of the furnace. The temperature difference of the left and right sides is greatly affected by the flue gas flow. In the upper part of the furnace, the material concentration and the uneven heating surface arrangement are also important reasons affecting the temperature characteristics.

A mathematical model of subcritical organic Rankine cycle (ORC) system is established for the flue gas waste heat of 120~150 ℃. Firstly, the thermal performance and economic performance of the system are analyzed at different heat source temperatures by taking R245fa as an example. Then, a multi-objective optimization study is conducted for six pure working fluids based on NSGA-Ⅱ algorithm. At last, working fluid selection and performance analysis of the ORC system with various heat source temperatures are carried out by TOPSIS method and gray correlation analysis. The results show that, in the temperature range of this study, the increase of superheat degree and evaporator pinch point temperature difference is not conducive to improve the system performance. The optimal working fluids are varied at different heat source temperatures, when the heat source temperature is 120 ℃, R601 has the best thermal performance, R245fa has the best economic performance and R1233zd has the best overall performance. The increase of heat source temperature is beneficial to improve the economic performance of the system. The optimal evaporation temperature of each working fluid increases with the heat source temperature. The gray correlation analysis indicates that the comprehensive performance of all six working fluids improves with the heat source temperature.

By riser two-phase flow model and thermodynamic model, exergy analysis for the thermosyphon-based trilateral cycle (TTLC) proposed in the previous work by the authors is carried out to investigate the exergy performance of the system and the relevant influencing factors. The results show that, the system exergy efficiency varies in the range of 15%~30% with the increasing inlet temperature of heat source, which always helps to enhance the exergy efficiency. As the inlet temperature of cooling source decreases, the exergy efficiency changes from 23%to 27% with an optimum value. An optimization opportunity exists for the temperature difference of heater at the hot side, for example, a setting value of 4 ℃ seems to be a better choice. The riser exergy loss rate is a key factor to determine the system efficiency, especially under the condition where the temperature difference of the cycle is relatively larger. Decreasing temperature pinch point of the heater helps to decrease the internal and external exergy loss rates of the heater, but will lead to more exergy destructions in other processes. However, it exerts positive effects on system efficiency on the whole.

Incoloy 800H is used for high temperature section of heat transfer tubes of the first high temperature gas-cooled reactor nuclear power unit in China, of which the highest design temperature is 675 ℃. The steam oxidation properties of the Incoloy 800H at the design temperature are investigated. The structure of oxide scale of the Incoloy 800H is characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy (EDS). The results show that, the oxidation kinetic curve of the 800H alloy in steam at 675 ℃ is close to the cubic law, namely the cubic of the weight gain is nearly proportional to the oxidation time. The oxide scale has a double-layer structure. The outer layer is mainly composed of Fe₃O₄, Fe₂O₃ and a small amount of Ni, and the inner layer is Cr₂O₃ nanocrystalline with a small amount of Ni, Al₂O₃ and TiO₂ particles distributed in it. Some internal oxide particles of Cr₂O₃, Al₂O₃ and TiO₂ are distributed in the matrix metal adjacent to the oxide layer.

Combined heat and power (CHP) units are affected by the output fluctuation of large-scale operating conditions, resulting in poor overall control quality of power generation load-extraction steam flow-throttle pressure in the turbine-boiler coordinated control system. To solve this problem, a multi-condition adaptive control method based on multi-agent deep deterministic policy gradient (MA-DDPG) is proposed. Firstly, according to the nonlinear dynamic mechanism of the unit, multiple operating condition sub-models considering the changes of state parameters are established, and the optimal operating condition sub-model is obtained by the integral function switching mechanism. For the multi-loop complex control requirements of the coordinated control system, a multi-agent synchronous operation mechanism is proposed, and the reward function is designed with the coordinated control objectives of rapid response, stable heating and safe operation. Finally, by training the agent to interact with the environment, the multi-loop gains are continuously adjusted online to achieve multi-condition adaptive control. Simulation results show that, compared with the conventional control method, the proposed method can effectively improve the load response rate under wide range operating conditions, and ensure the stability of heating.

Control of main steam temperature (MST) is becoming more and more challenging because of unknown disturbances caused by frequent and extensive load changes and strict control requirements for the efficiency and safety. To this end, considering the sluggish responses to the disturbances caused by high order dynamics, an anti-disturbance control scheme with stair-like dynamic matrix control (SDMC) algorithm as the core is proposed to solve fundamentally the control problem of large delay, big inertia and multiple disturbances in MST. This study aims to provide technical support for the clean and efficient use of coal and the large-scale consumption of renewable energy sources in China. A simulation example shows that the proposed improved equivalent input disturbance observer (IEIDO) can realize real-time estimation and compensation of disturbances, while SDMC can not only ensure the rapidity and stability of the steam temperature control system, but also achieve disturbance suppression according to the introduction of measured disturbance feed-forward compensation technology. Therefore, the proposed scheme can guarantee the safety, stability, economy and flexibility of the unit operation, which has a promising application future in power industry.

Using ceramic membrane to recover moisture from gas is a feasible way that not only can realize the recycling of resources, but also can alleviate environmental pollution. By taking double-row ceramic membrane module as the research object, the heat and mass transfer of water vapor transport was theoretically analyzed, the physical model was established, and numerical simulation was carried out according to the boundary parameters under actual conditions. Then, a pilot test platform was built on a coal-fired unit to carry out the experimental research on the purified flue gas after wet desulfurization. The results show that, the amount of recovered water decreased linearly from 29.45 kg/h to 18.13 kg/h by increasing the cooling water temperature from 25 ℃ to 36 ℃. With the growing of flue gas flowrate, the recovered water gradually increased, but the growth rate gradually decreased. The deviations of the recovery water amount between the calculated results and the experimental data were less than 7%.

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.

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.

To realize stable combustion and refined combustion adjustment of boilers and to gain an in-depth understanding of the jet characteristics of direct flow pulverized coal burners, by taking the pulverized coal burner with surrounding air and its horizontal branch of the secondary air of a quadrangular tangentially pulverized coal boiler as research objects, the effects of throttle column height, secondary air door opening, and wind baffle angle on airflow characteristics are analyzed by numerical simulation under thermal condition. The calculation results show that, for the pulverized coal burner with a small nozzle area of the surrounding air and a thicker horizontal branch of secondary air, adding a throttle column at the position of a secondary air door can effectively improve the uniformity of velocity distribution of the nozzle area of the surrounding air. The opening degree of the secondary air door poses no noticeable effect on the airflow velocity distribution near the nozzle area of the surrounding air, and adding a wind baffle at the burner nozzle can improve the rigidity of primary air and the protection of surrounding air to primary air.

In order to reduce the air and pulverized coal distribution deviation of pulverized coal system, optimize the boiler combustion condition and expand the application range of pulverized coal distributor, a new pulverized coal distributor needs to be developed. By means of test bench model test, a new type pulverized coal distributor is developed. The structural design of the distributor model is completed, and the key performance of the distribution is studied, such as the effects of the pulverized coal distributor's coal amount damper resistance characteristics, the air and pulverized coal distribution and regulating characteristics, and resistance regulation on the distribution characteristics, as well as the effect of system air speed on the distribution characteristics. The results of model test and engineering application show that, the new pulverized coal distributor can effectively control the air volume deviation of the pulverized coal delivery pipeline within ±5% and pulverized coal deviation within ±10%. After the engineering transformation and leveling test of the new pulverized coal distributor for No.3 boiler of a power plant, the thermal load deviation of furnace can be effectively reduced, and the deviation of the two metal wall temperature points, which can reach 150 ℃ before transformation, can be controlled within 15 ℃, which greatly improves the safety and reliability of the boiler operation. The development and engineering application of the new pulverized coal distributor have certain guidance and reference significance for reducing the distribution deviation of pulverized coal in pulverized coal system and solving the series of problems such as partial burning, over temperature and corrosion in boiler operation.