Against the dual backdrop of urgent global climate governance and low-carbon transformation demands of the coal-fired power industry, carbon capture and storage (CCS) is widely recognized as a critical pathway to deep emission reduction in the power system. However, the high cost of CCS technology has severely hindered its large-scale promotion. To address this cost optimization challenge, this study aims to systematically explore the cost-driven mechanisms of the full-chain CCS system, identify key influencing factors, and propose a targeted cost-reduction paradigm, providing theoretical and practical support for the scientific deployment and commercialization of CCS in coal-fired power plants.

This study adopted the ITEAM-CCUS quantitative evaluation model, covering the full-chain CCS and integrating three core modules: geological carbon storage assessment, techno-economic analysis, and source-sink matching optimization. A systematic multi-parameter sensitivity analysis was conducted based on a sample of 165 domestic coal-fired power plants. These samples were selected to represent different regional distributions, unit capacities, and operational conditions, ensuring the generalizability and reliability of the research results. The analysis focused on key technical, economic, and geological parameters, such as absorbent regeneration heat consumption, coal price, plant utilization hours, electricity price, transportation distance, and reservoir properties.

The study revealed that the average levelized cost of the full-chain CCS is 303 yuan per ton of CO₂. Among the four chains, the capture and compression stages account for over 80% of the total cost, emerging as the primary focus for cost reduction. Specifically, capture cost is most significantly influenced by absorbent regeneration heat consumption, coal price, and plant utilization hours, and reducing regeneration heat consumption through technological innovation or improving plant operational efficiency can effectively lower capture costs. Compression cost shows a strong correlation with electricity price. Pipeline transportation cost is constrained by transportation distance and economies of scale. Storage cost is extremely sensitive to geological parameters such as reservoir’s permeability coefficient, thickness, and depth-reservoirs with higher permeability, greater thickness, and moderate depth are more conducive to reducing drilling, injection, and monitoring costs.

Based on the quantitative findings, this study proposes a systematic “scale-geology-energy efficiency synergy” cost-reduction paradigm. The specific pathways include technological innovation for low-energy consumption in the capture stage, large-scale infrastructure sharing across the full-chain CCS, refined operation and management of the CCS system, and policy incentives. This research clarifies CCS cost structures and driving factors, providing a feasible framework for governments, enterprises, and research institutions. It offers important theoretical and practical reference for promoting large-scale, commercial CCS application in coal-fired power plants, advancing power system decarbonization, and supporting global climate governance.

Conventional combined heating and power (CHP) systems often suffer from suboptimal thermal integration and limited exergy utilization, resulting in low overall energy efficiency and significant carbon emissions. To address these challenges, this study proposes a novel high-efficiency CHP system based on the synergistic integration of a solid oxide fuel cell (SOFC) and a lithium bromide (LiBr) absorption heat pump. The architecture is specifically designed to maximize cascaded energy recovery and enhance comprehensive thermodynamic and economic performance.

A comprehensive steady-state model encompassing thermodynamic and economic analysis was developed to evaluate the system behavior. In the proposed configuration, unreacted fuel in the SOFC anode exhaust is combusted using oxy-fuel technology, yielding a CO₂-concentrated flue gas suitable for carbon capture while simultaneously upgrading waste heat quality. The high-temperature flue gas is then recovered through an advanced cascaded heat exchanger network, sequentially enabling cathode air preheating, endothermic methane reforming, and high-pressure steam generation. This steam serves as the thermal driving source for the LiBr absorption heat pump to meet heating demands. A detailed parametric sensitivity analysis was conducted to investigate the effects of the steam-to-carbon ratio, SOFC operating temperature, and fuel utilization factor on key performance indicators.

Simulation results show that increasing the steam-to-carbon ratio monotonically reduces both SOFC electrical efficiency and overall thermal energy utilization efficiency, whereas the coefficient of performance (COP) of the absorption heat pump remains stable at approximately 1.72. Higher SOFC operating temperatures significantly improve electrochemical kinetics and flue gas quality, thereby enhancing both electrical and thermal performance. A clear trade-off is observed with fuel utilization: higher fuel utilization factor increases electrical output but diminishes the availability of high-grade heat for downstream recovery. Under optimized conditions (with the steam-to-carbon ratio of 2, temperature of 1 000 ℃, and fuel utilization ratio of 0.85), the system achieves an electrical efficiency of 52%, an exergy efficiency of 56.6%, and an overall thermal energy utilization efficiency of 100.54% (defined on the basis of the fuel’s lower heating value, including all recovered thermal energy). Compared to a conventional natural gas-fired CHP benchmark, the proposed system improves the thermal utilization efficiency by 20%, and increases the exergy efficiency by 2.6%. Economic evaluation yields a levelized cost of exergy of 0.102 6 dollars/(kW·h) and a dynamic payback period of 8 years under current industrial energy pricing.

This coupled system significantly improves the energy utilization efficiency and comprehensive performance through the optimization of the energy cascade utilization mode. It demonstrates substantial economic feasibility and potential for engineering applications. The identified influence mechanisms of key parameters provide a theoretical foundation for the optimal design and operational control of such systems.

In the context of achieving the “dual-carbon” goals in the new era, coal-fired cogeneration systems are required to be highly efficient, flexible, and low in pollution and carbon emissions.

To tackle these challenges, this study proposes a novel system that integrates a supercritical CO₂ cycle with split-flow heating and low-temperature regeneration (SR-SCO₂-CHP), an ultra-low emission (ULE) flue gas control module, and a vacuum temperature swing adsorption (VTSA) carbon capture module (denoted as the SR-SCO₂-CHP-ULE-VTSA system). A system using monoethanolamine (MEA) for carbon capture (SR-SCO₂-CHP-ULE-MEA) serves as the benchmark for comparison. A comparative exergy analysis is conducted.

The results demonstrate that the proposed system achieves superior exergy efficiency across all electrical loads, because the exergy loss of the VTSA carbon capture submodule is less than one-third of that of the MEA. The exergy losses of MEA mainly occur in the absorption tower and desorption tower, which account for 80% of the total exergy losses of the carbon capture submodule. However, the exergy losses of VTSA adsorption & desorption tower and the pressure machine are relatively large, accounting for more than 60% of the total exergy losses of the carbon capture submodule. At full load, its exergy efficiency reaches 39.84%, significantly outperforming the benchmark system’s 35.16%. Furthermore, the proposed system enables effective thermo-electric decoupling through adjustments in the heat split ratio (x₁) and the split ratio of CO₂ turbine driving vacuum pump (x₂). The exergy efficiency of the system decreases as the split ratio x₁ and x₂ increase under any electrical load, and the optimal split ratios of x₁ and x₂ increase as the electrical load decreases. At 100% electrical load, the optimal values for x₁ and x₂ are 0.52 and 0.14, respectively. The carbon reduction capability of the proposed system is also remarkable. Across the electrical load range from 100% to 30%, the carbon reduction increases from 11.9 g/(kW·h) to as high as 85.3 g/(kW·h), demonstrating a significant advantage over the benchmark system.

This work confirms the SR-SCO₂-CHP-ULE-VTSA system as a promising solution for highly efficient and low-carbon coal-fired cogeneration. It should be noted that in terms of economic performance, the initial investment of the carbon capture module of the SR-SCO₂-CHP-ULE-VTSA system is closely related to the performance of the adsorbent material, and further optimization of the adsorbent is required to reduce equipment size and cost. Additionally, in terms of operation, its carbon capture module has a complex structure and high requirements for multi-tower operation switching, so its technical maturity needs to be further improved to promote its industrial application.

Biomass power generation plays a crucial role in China’s efforts to achieve the “dual carbon” goal. The goal focuses on peaking carbon dioxide emissions and reaching carbon neutrality within a predefined timeline. However, high chlorine and alkali metal contents are naturally present in biomass fuels. Due to this characteristic, biomass boilers are prone to severe high-temperature corrosion during operation. The long-term reliability and safety of boiler systems are undermined by this issue. A systematic and comprehensive review of high-temperature corrosion in biomass boilers is provided in this paper. The corrosion mechanisms, influencing factors, and mitigation technologies are covered, with the aim of providing a valuable reference for both research and engineering practices.

Firstly, the typical characteristics of high-temperature corrosion in biomass-fired boilers are outlined. On this basis, the corrosion mechanisms involving key media such as chlorine, alkali metals, and sulfur are elaborated. Subsequently, the influence of multiple critical factors on corrosion behavior is analyzed in detail. The reaction rate of corrosive processes is directly regulated by temperature. The corrosive environment is changed by flue gas composition. The formation of protective or corrosive deposits is affected by ash composition. The intrinsic corrosion resistance of boiler components is determined by material properties. Finally, a series of prevention and control technologies are summarized. These technologies have been validated through laboratory experiments or long-term engineering practice. They include fuel pretreatment (to reduce corrosive constituents), coating protection (to isolate metal surfaces from corrosive media), additive inhibition (to suppress harmful chemical reactions), and external fluidized beds (to optimize combustion and corrosion conditions). The unique application features, advantages, limitations and economic efficiency of each technology are also discussed.

Future research can be deepened from three key aspects. First, advanced materials science should be integrated to elucidate the microscopic mechanisms of multi-medium coupled corrosion. Interface reactions and damage evolution processes at the atomic and molecular levels can be uncovered. Second, efforts should be intensified to develop novel high-performance protective materials. These materials should be endowed with exceptional high-temperature stability, corrosion resistance and mechanical strength. The harsh operating environments of biomass boilers must be withstood by them. Third, an integrated and collaborative control strategy should be established. This strategy is synergistically combined with fuel pretreatment, scientific additive selection, optimized operational parameters, and advanced material protection. Full-cycle, multi-dimensional corrosion control is the ultimate goal to be achieved. Through the synergistic innovation of mechanism research, advanced material development and systematic prevention-and-control technologies, it is expected to provide essential support for the safe, efficient, and low-cost operation of biomass boilers.

To achieve recovery and utilization of low-grade waste heat, we proposed a phase change thermal storage unit incorporating “tree-branch fins + foam metal”, and co-optimized its structural and material parameters using response surface methodology and orthogonal experiments.

Under typical operating conditions (80 ℃, 0.005 m/s), tree-branch fins reduced the melting time of the phase change material (PCM) by 10.7% compared to straight fins, with optimal parameters including a length ratio of 1.143, a width ratio of 1.057, and a branching angle of 68.987°. Regarding system structure, the counterflow arrangement of dual heat exchanger tubes decreased the melting time to 558 s, and further filling with foam metal shortened it to 181 s. Although increasing porosity enhances the proportion of PCM, it weakens the structural support of the metal framework, thereby prolonging the melting time.

In conclusion, the integration of tree-branch fins and foam metal significantly improves the thermal storage performance of phase change thermal storage devices. Subsequently, staged thermal energy storage can improve the efficiency of heat storage. The optimal configuration for a three-stage cascade is put forward: Stage I: 0.9 porosity nickel foam + n-octadecane; Stage II: 0.5 porosity nickel foam + n-octadecane; Stage III: 0.5 porosity nickel foam + stearic acid PCM.

It can provide an integrated design basis for the efficient capture and reuse of low-grade waste heat at 50~60 ℃.

Compressed air energy storage technology is mature and flexible to operate, making it a highly promising energy storage solution. To effectively improve the performance of compressed air energy storage systems, this study proposes an integrated system that couples them with concentrated solar power (CSP) plants.

During the energy storage phase, low-temperature condensate from the solar thermal power plant’s regenerative system is used to cool the high-temperature compressed air at the compressor outlet, thereby recovering and reusing the compression heat. During the energy release phase, the compressed air is heated in stages using high-temperature molten salt and high-temperature feedwater from the CSP plant. Through system integration, the compression heat is effectively utilized, while simultaneously reducing the thermal storage equipment required in the original compressed air energy storage system. A thermodynamic model of the coupled system was constructed, and energy, exergy, and economic analyses were conducted on the proposed coupled system to evaluate its performance.

The proposed system achieved a round trip efficiency of 74.95% and an exergy efficiency of 79.78%, with an energy storage density of 8.18 MJ/m³. Furthermore, the system’s dynamic payback period was 4.42 years，and its net present value was 49.358 9 million yuan.

The proposed integrated system of solar thermal power station and compressed air energy storage exhibits significant efficiency improvement and good economic performance, providing valuable reference for the development of renewable energy coupled energy storage systems.

The low-temperature (–20~ –40 ℃) oxidation adsorption of multiple pollutants from coal-fired flue gas onto activated carbons enables their integrated removal, which has promising application prospect and environmental benefits.

This article studied the adsorption processes of NO and SO₂ by four activated carbons (graded-pore activated carbon, coal-based activated carbon, and two coconut shell-based activated carbons) in inert atmosphere and simulated flue gas under low temperature conditions of –20 ℃.

The experimental results showed that in an inert atmosphere, the adsorption performance of the four activated carbons for NO was weak, with a saturated nitrogen capacity of less than 0.07 mg/g, and the saturated sulfur capacity for adsorbing SO₂ was 31.70~57.07 mg/g. In simulated flue gas conditions, the presence of O₂ increased the saturated nitrogen capacity of activated carbons by three orders of magnitude and the saturated sulfur capacity by 2~5 times. The optimal coconut shell activated carbon-2 had a saturated nitrogen capacity of 175.70 mg/g and a saturated sulfur capacity of 320.65 mg/g. Density functional theory (DFT) calculations show that the adsorption binding energies of NO, SO₂, and their oxides on the zigzag edge carbon model follow the order of NO₂> SO₃> SO₂> NO. After NO and SO₂ are oxidized by O₂ into NO₂ and SO₃, their adsorption on activated carbon surfaces is significantly enhanced.

The research results can provide an important theoretical basis for the integrated adsorption and removal of NO and SO₂ in coal-fired flue gas under low temperature conditions.

To address the issues of low reheated steam temperature and local overheating of platen superheaters (PSH) during low-load operation of a 660 MW ultra-supercritical tangentially fired once-reheat boiler, this study proposed a wall-mounted flue gas recirculation (FGR) arrangement in the burner region. The aim was to synergistically raise reheated steam temperature and suppress PSH overheating while maintaining combustion stability.

Numerical simulation was performed at 40% rated load to optimize the proposed layout. First, the baseline case and corner-mounted and wall-mounted concentrated FGR arrangements were compared. Subsequently, the feasibility of wall-mounted grouped injection was investigated.

The results indicated that: corner-mounted FGR significantly increased the ignition distance of pulverized coal jets, which adversely affected low-load combustion stability. Both fire-side and rear-side concentrated FGR increased the heat absorption of the high-temperature reheater, but neither could simultaneously mitigate PSH local overheating. Fire-side grouped FGR substantially enhanced heat absorption of the reheater but still carried a risk of PSH overheating, whereas rear-side grouped FGR reduced the overheating risk but yielded only limited reheater improvement. A combined grouped arrangement, in which flue gas was injected through the two lower layers on the fire-side wall together with the upper layer on the rear-side wall, increased the heat absorption of the reheater by 18.9%, effectively mitigated local overheating of the PSH, and maintained stable combustion.

These findings provide design and optimization references for safe, flexible, and efficient boiler operation across wide load ranges in next-generation coal-fired power plants.

To investigate the effects of biomass gas co-firing on combustion stability and in-furnace parameters under low-load conditions, a 660 MW tangentially fired boiler was taken as the research object to carry out the study. A stability index was proposed, and a combined approach of numerical simulation and artificial neural network (ANN) was employed.

Comparative analysis was conducted between pure coal and co-firing conditions at loads of 100%, 70%, 50%, and 30%.

The results show that the deviation of the temperature stability coefficient (M_T) under co-firing is less than 3.9%, indicating stable combustion at low load conditions. When the unit load decreases from 100% to 70%, the average temperature in the main combustion zone drops by 147.87 K for pure coal and 69.37 K for co-firing, indicating a slower temperature decay. At 30% load, the NO_x volume fractions in the reduction and burnout zones under co-firing are 0.051 2% and 0.044 4%, which are lower than 0.093 3% and 0.078 6% under pure coal combustion condition, with smaller fluctuations of other parameters. Furthermore, an artificial neural network (ANN) model was developed to describe the complicated relationships among in-furnace parameters, and the results show that the regression coefficients R² for temperature, CO₂ volume fraction, and NO_x volume fraction predictions are all greater than 0.96 in both pure coal and co-firing conditions.

This study provides support for optimization and prediction of low-load operation in biomass gasification co-firing boilers.