With the launch and promotion of national carbon trading market, accurate carbon emission data of emission control enterprises is crucial for the government to formulate policies and build carbon trading mechanisms. The current official carbon emission accounting method in China, the emission factor method, is simple and easy to use, but is highly influenced by human factors and can easily lead to quality issues with carbon data. Therefore, a rapid analysis method for coal quality indicators suitable for coal-fired power plants in the carbon market is developed based on laser induced breakdown spectroscopy (LIBS) technology. Combined with partial least squares regression (PLSR), a predictive model for carbon content and heat generation of coal elements is established. The results show that, the average absolute error (AAE) of the prediction set for the established dry based high calorific value and carbon content model is 1.10 MJ/kg and 2.72%, respectively, which can achieve fast and high-frequency detection of daily coal samples in power plants. In the application research of carbon accounting, examples show that, compared with the conventional daily measurement method, the relative deviation of monthly carbon emissions accounting obtained by the LIBS rapid detection method for daily measurement is only 0.40%, which is more accurate than that obtained by the monthly reduced coal sample detection method. In the application research of carbon verification, based on the results of the element carbon content measurement method, the average relative error (ARE) of the carbon emissions calculated using the LIBS rapid detection method has a reduction of 6.73~18.99 percentage points compared with that using the complete default value method. The LIBS rapid detection method has a testing accuracy that is close to conventional laboratory results, which can be applied to carbon verification and coal quality data verification, and be developed into a fast and low-cost practical technology to assist carbon accounting.

Carbon capture, utilization and storage (CCUS) is a key technology to mitigate the impact of CO₂ emissions on the environment, and CO₂ geological storage and utilization is an important part of CCUS. This paper analyzes the global development trend of CO₂ geological storage and utilization technology, reviews the current development situation in China from the aspects of policy system construction, project implementation and research results, interprets the research frontiers in this field through literature analysis, and prospects the development of CO₂ geological storage and utilization. Current research focuses on the CO₂ geological storage and utilization in depleted oil and gas reservoirs, induced seismic mechanism and monitoring, leakage monitoring and environmental assessment, CO₂ geological storage and energy resources cooperative development and utilization, and rapid mineralization storage. In the future, research in this field should focus on the complex multi-field and multi-phase study in CO₂ geological storage and utilization, building a whole-process intelligent CO₂ geological storage and utilization system, and exploring diversified CCUS industry development models.

Chemical absorption using amine solution takes the dominant position for post combustion CO₂ capture of coal-fired power plants, the regeneration of amine is thermally driven, consuming large amount of steam extracted from turbine units, which results in severe power generation efficiency penalty and higher power generation cost. This limitation restricts its large-scale application in terms of both single-unit capacity and project quantity. Optimizing the heat application method in the system is an important approach to address the aforementioned issues. Focusing on the thermal energy integration utilization between the carbon capture subsystem and the power plant system, discussions and investigations are performed from the perspectives of thermal integration optimization theory and engineering energy system optimization. In terms of thermal integration optimization theory, the principles, usage methods, application results and the limitations of the exergy analysis and the pinch point analysis method in coal-fired carbon capture systems are discussed, and the suggested research interests are proposed. In the aspect of engineering energy system optimization, the beneficial effects of steam extraction parameters optimization, superheated steam utilization methods, condensate waste heat utilization methods, carbon capture and compression waste heat utilization methods, and various auxiliary machine application methods are analyzed, as well as the feasibility and economic problem of the mentioned methods during implementations. The research can provide references and ideas for further reducing system energy consumption of carbon capture of coal-fired power plants.

Direct air carbon capture (DAC) technology has been booming in the past decade, and now it has gradually developed from laboratory toward commercial device. Because the adsorption DAC is more promising than absorption DAC, some companies have launched DAC demonstration projects based on adsorption. However, there is relatively little introduction to these companies and projects based on adsorption DAC in current research, and a comprehensive study has not yet been formed. In view of the above reasons, some representative companies owning adsorption DAC technologies and their projects are investigated through existing literatures and their corporate websites, and the key contents are focused. In addition, the device types of these enterprises are divided into centralized devices and integrated devices according to the arrangement of equipment, and the characteristics of these two types of devices are introduced. By summarizing the characteristics of DAC enterprises and technologies, it is found that most enterprises are committed to reducing operation and investment costs, so the possible cost reduction methods in the future industrialization process are put forward and the effects are analyzed.

In the oxygen combustion CO₂ cycle, heat integration of the air separation unit (ASU) is commonly used to improve the matching of the heat recovery process. However, the ASU heat integration increases the heat recovery load, and the relatively low load ramp rate of the ASU affects the overall performance of the system. To eliminate the need for ASU heat integration and further enhance cycle efficiency, a method involving split adiabatic compression is proposed to balance the thermal capacities of the hot and cold streams. A power generation system model based on the gasification oxygen combustion CO₂ cycle is developed in Aspen, and the thermodynamic performance of the system, as well as the effect of ASU heat integration, are analyzed. A recompression system is also introduced for comparison. The results show that, the conventional system with integrated ASU heat has a net efficiency of 43.39%. Compared with a system without heat integration, the power consumption of the ASU increases by 19.9 MW, while 180.8 MW of heat integration is provided, resulting in a 1.64 percentage points increase in net efficiency. Considering limitations in heat recovery, the optimal split mass flow rate for the recompression system is 258.2 kg/s. Compared with the ASU heat integration, the recompression system reduces the heat recovery load by 59.8 MW, and the average heat exchanger temperature difference is further reduced by 3.1 ℃, improving the net efficiency to 43.52%. The study reveals the mechanism by which heat integration affects the efficiency of the oxygen combustion CO₂ cycle and proposes an optimization to decouple the power cycle from the ASU heat integration through the recompression process, providing theoretical guidance for the parameter design of the recompression system.

Post-combustion carbon capture is the underpinning technology and necessary choice for low-carbon power generation, yet its integration into natural gas combined cycle (NGCC) power plants will significantly reduce the plants’ power generation efficiency. In order to reduce the efficiency penalty of the power plants integrated with decarbonization system and improve the energy utilization efficiency of the integrated system, a novel post-combustion carbon capture process that comprehensively recovers the waste heat and liquefied natural gas cold energy is innovatively proposed. Firstly, the key operating parameters of the conventional carbon capture process, including stripper pressure and lean solvent loading, are optimized with sensitivity analysis. On this basis, design and evaluation of novel process is performed. In the novel process, a back-pressure turbine is utilized to recover the pressure energy of the extracted low-pressure steam and assist the lean vapor compression as well as recover the inter-cooling heat of CO₂ compression to heat the reflux condensate of the stripper, which reduces the minimum regeneration energy consumption by 17.3% (to 3.35 GJ) at the flash pressure drop of 90 kPa. Furthermore, the extracted low-pressure steam is reduced from 68.40 kg/s to 48.95 kg/s by recovering the superheat of steam extraction. Aiming at solving the problems of high energy consumption of the conventional CO₂ compression process and the waste of cold energy in the liquefied natural gas regasification process, a novel CO₂ two-stage compression and intermediate liquefication process is proposed, reducing compression work by 34.5%, and the cooling load and the number of equipment were significantly decreased. Exergy analysis results show that the exergy efficiencies of the novel carbon capture process and CO₂ compression process increase from 23.12% and 62.19% to 29.48% and 65.96%, respectively. The simulation results show that, the net power output of the plant integrated with the novel carbon capture process increases from 341.93 MW to 358.75 MW, resulting in a significant energy saving by increasing the net power output efficiency from 48.85% to 51.25% and decreasing the efficiency penalty from 13.77% to 9.53%.

When thermal power units employ amine-based carbon capture, electro-carbon coupling exists. To enhance the load flexibility tracking performance of decarbonized units, a variable-load control strategy based on electric-carbon coordination is proposed. Using existing data, an electric-carbon coordinated control system model for drum boiler thermal power units was established through system identification. The response time scales of reboiler load to power generation load and carbon capture rate were analyzed. Based on this, a dual-control loop for power generation load was designed, incorporating both decarbonization steam extraction and fuel quantity regulation. Furthermore, to address the effect of long time scales on carbon capture rate, the transient quantities of reboiler load variation throughout the process were reconstructed, and a flexible power generation load control method based on electric-carbon synergy was proposed. Simulation tests on a 300 MW unit demonstrated that, compared with the conventional coordinated control strategies, the proposed strategy ensures performance metrics for thermal load and carbon capture rate while improving both the load variation control rate and AGC performance metrics by an average of 100% or more.

To address the issue of imbalanced fault samples in training machine learning models for gas turbine gas path faults, a data augmentation method based on Time-Series GenerativeAdversarial Networks (TimeGAN) is proposed. First, transient operational data from actual gas turbine gas path faults are cleaned, standardized, processed through feature engineering, and reduced using PCA to preserve critical fault features. Next, a TimeGAN model comprising embedding, generation, discrimination, and reconstruction modules is constructed, and Bayesian optimization is performed using the Optuna hyperparameter optimization tool to determine the optimal hyperparameters. Finally, the quality of the generated data is comprehensively evaluated through prediction metrics, classification metrics (based on a posterior RNN discriminator), and visualization metrics (PCA and t-SNE). The results demonstrate that data generated by TimeGAN achieve a mean absolute error of 4.47% in prediction tasks, exhibiting high similarity to real data in terms of statistical features and latent 2 representation space, making it difficult for the discriminator to distinguish between the two. Visualization analysis furtherconfirms thatthe clustering patternsanddistribution trendsof thegenerated dataclosely resemble thoseoftherealdata.

In the context of “carbon peak” and “carbon neutrality”, using renewable electricity to electrolyze water to produce hydrogen and synthesize ammonia can not only consume renewable energy and solve the problem of hydrogen storage and transportation, but also promote the green transformation of the conventional ammonia synthesis process. To investigate the effect of different hydrogen production schemes on technical and economic performance of the synthetic ammonia system, the system thermal and economic performance of three hydrogen production schemes, including proton exchange membrane electrolyzer hydrogen production, proton exchange membrane electrolyzer and alkaline water electrolyzer hydrogen production in a 1:1 ratio, and alkaline water electrolyzer hydrogen production, are compared and analyzed. The hot and cold integration of the synthetic ammonia system with coordinated hydrogen production by proton exchange membrane electrolyzer and alkaline water electrolyzer is analyzed by combining pinch analysis with mathematical programming. The results show that, the system exergy efficiencies of the above three hydrogen production schemes are 60.3%, 56.1% and 52.5%, respectively, and the carbon emissions of ammonia also increase due to the increase in net power consumption of the system. Benefiting from alkaline water electrolyzer’s mature hydrogen production process, the alkaline water electrolyzer hydrogen production scheme has the shortest investment payback period of 6.4 years, while the proton exchange membrane electrolyzer hydrogen production scheme has the longest investment payback period of 12.8 years. The thermal integration analysis of the synthetic ammonia system for the coordinated hydrogen production of proton exchange membrane electrolyzer and alkaline water electrolyzer shows that the low-temperature waste heat below 100 ℃ in the system is released to the environment via cold utilities. In addition, increasing the operating temperature of the electrolyzer is beneficial to improving thermal performance of the system, while lowering electricity price and increasing the annual operating hours of the system will help to improve the economic performance of the system.

The combustion characteristics of coal-fired power plant boilers co-firing ammonia and its impact on the boilers are reviewed, aiming to provide theoretical and practical basis for large-scale application of ammonia as an alternative fuel to coal. By systematically reviewing existing literatures, the study examines the fundamental characteristics of ammonia combustion, flame propagation, flame morphology, and their effects on heat transfer, heat surface safety, boiler efficiency, and exergy efficiency of coal-fired boilers. The study also explores combustion enhancement methods such as oxygen-enriched combustion, preheated combustion, and hydrogen-assisted combustion. The results indicate that, co-firing ammonia can mitigate issues like ash deposition, slagging, wear, and high-temperature corrosion on heating surfaces, but it increases the acid dew point of flue gas, potentially exacerbating low-temperature corrosion. Co-firing ammonia increases the irreversibility of the combustion process, leading to higher furnace losses, although oxygen-enriched combustion can mitigate these losses. While there is substantial research on ammonia co-firing with small molecule gaseous fuels, there is limited study on its co-firing with large molecule solid hydrocarbons like coal. The effect of ammonia blending combustion on boiler heat transfer, heating surface safety, and boiler efficiency is significant. The decrease in flame temperature, reduction in flue gas soots, and changes in flue gas composition can affect heat transfer efficiency and heating surface conditions. Attention should be paid to low-temperature corrosion and unburned ammonia emissions. Ammonia blending combustion is an effective low-carbon combustion technology, but its application in large utility boilers still faces many challenges. It requires further in-depth research on combustion mechanisms and practical application effects to optimize combustion equipment and improve system efficiency.