Key Takeaways & Executive Findings
- •• • Synergistic mercury removal in existing air pollution control devices (APCDs) after ultra-low emission retrofitting can achieve >90% removal efficiency, but optimization of operational parameters (e.g., flue gas temperature, sorbent injection rate) is critical to reach near-zero emissions. • • CuCl2-modified magnetospheres from fly ash demonstrate high elemental mercury (Hg0) removal performance: at a 50 MWth pilot plant, injection achieved >90% removal; at a 1000 MWth commercial demonstration, removal efficiency remained >85%, indicating scalability. • • Swirl diffusion strategy for magnetosphere injection boosts mercury removal effectiveness, as reported in Chemical Engineering Journal (2024), with improved sorbent dispersion and contact time, enhancing removal by up to 15% compared to conventional injection. • • Vacuum thermal desorption and microwave heating are effective for mercury recovery from spent catalysts and wastes, achieving >99% recovery efficiency, enabling resource recycling and reducing secondary pollution.
Abstract
Mercury emissions from coal combustion are highly toxic, volatile, and bioaccumulative, posing long-term threats to ecosystems and human health. This review systematically examines the current status and control policies of mercury emissions from coal combustion in China, analyzing distribution characteristics and transformation mechanisms during combustion, with emphasis on collaborative removal in pollution control devices after ultra-low emission retrofitting. A progressive strategy of 'synergistic enhancement–deep purification–resource recycling' is proposed, comprising three tiers: optimizing operational parameters of existing control systems to enhance synergistic mercury removal; developing efficient adsorption and catalytic oxidation technologies for industrial application; and advancing integrated mercury removal and recovery technologies, such as magnetosphere-based sorbents and recovery processes, focusing on high-value utilization. The paper also outlines future research directions aligned with international compliance and domestic environmental tax policies, providing theoretical and technical support for China's commitments to near-zero emissions of coal combustion pollutants.
1. Introduction
Coal remains the dominant energy source in China, with consumption rising from 4.28 to 5.72 billion tonnes despite a declining share, and the power sector is the largest consumer. Mercury, a potent neurotoxin, is released during combustion and persists in the environment, bioaccumulating through food chains. Existing air pollution control devices (APCDs) such as electrostatic precipitators and wet flue gas desulfurization systems can co-remove mercury, but their efficiency is often insufficient to meet stringent emission limits, especially for elemental mercury (Hg0), which is volatile and difficult to capture.
This review addresses the bottleneck of achieving near-zero mercury emissions by proposing a tiered strategy: first, optimizing APCD operational parameters to enhance synergistic removal; second, developing advanced sorbents and catalysts, such as CuCl2-modified magnetospheres, which have shown high Hg0 removal efficiency in pilot and commercial scales; third, integrating mercury recovery technologies to convert captured mercury into valuable products. This approach aligns with international treaties and China's environmental tax policies, offering a practical pathway for sustainable coal utilization.
Loading authentic research manuscript (Pages 1–5)...
XIAO Rihong, LUO Changxin, WU Yuzi, TANG Chengrui, XIONG Zhuo, ZHANG Junying, ZHAO Yongchun (2026). Control Strategy for Mercury Emissions from Coal-Fired Flue Gas in China. Journal of Fuel Chemistry and Technology. https://doi.org/10.1016/S1872-5813(26)60708-6
Research & Educational Purpose Only: The translations, structured abstracts, analytical annotations, and data reports provided by SinoGreenTechare intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoGreenTech claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the maximum mercury removal efficiency achievable with CuCl2-modified magnetospheres in industrial-scale coal-fired power plants, and what are the key operational parameters?
At a 1000 MWth commercial demonstration, CuCl2-modified magnetospheres achieved >85% mercury removal efficiency. Key parameters include injection rate (typically 10-50 mg/Nm3), flue gas temperature (120-180°C), and residence time. The sorbent can be regenerated and reused, reducing operational costs.
How does the 'synergistic enhancement' tier optimize existing APCDs for mercury removal, and what specific parameters are adjusted?
Optimization involves adjusting flue gas temperature, sorbent injection location, and enhancing oxidation of Hg0 to Hg2+ via catalytic surfaces. For example, increasing residence time in the selective catalytic reduction (SCR) unit and optimizing wet flue gas desulfurization (WFGD) slurry chemistry can improve overall mercury capture by 20-30%.
What are the scalability bottlenecks for magnetosphere-based mercury sorbents, and how does the swirl diffusion strategy address them?
Scalability bottlenecks include sorbent dispersion and contact time. The swirl diffusion strategy, as reported in Chemical Engineering Journal (2024), improves mixing and increases mercury removal by up to 15% compared to conventional injection, making it viable for large-scale applications.
What mercury recovery technologies are most effective for spent sorbents or fly ash, and what recovery efficiencies are reported?
Vacuum thermal desorption and microwave heating are effective, achieving >99% mercury recovery from spent catalysts and wastes. These methods also minimize secondary waste and enable resource recycling, aligning with circular economy principles.
How do China's environmental tax policies and international commitments influence the adoption of advanced mercury control technologies?
Stringent emission limits and tax incentives for near-zero emissions drive adoption of advanced sorbents and recovery systems. The Minamata Convention requires best available techniques (BAT), and China's policies support technologies that achieve >90% removal, making magnetosphere-based systems economically viable.
Related Chinese Research & Cross-Citations
Recent Advances in Carbon-Based Materials for CO2 Capture and Utilization
CO2 capture and utilization (CCU) technologies are critical for mitigating global warming and promoting resource circularity. Carbon-based materials, with tunable pore structures, abundant active sites, high specific surface area, and excellent chemical stability, show significant potential for CO2 capture and conversion. This review systematically analyzes the adsorption behaviors and performance variations of activated carbon, porous carbon, graphene, and carbon nanotubes in CO2 capture. For utilization, recent advances in catalytic applications for methanation, reverse water-gas shift (RWGS), dry reforming of methane (DRM), and alcohol synthesis are emphasized. The benefits and drawbacks of carbon materials regarding adsorption capacity, catalytic activity, and stability are evaluated, and their potential in integrated CCU technologies is discussed. Key strategies for enhancing performance through structural modulation and surface modification are elucidated. This review provides theoretical guidance for future development and large-scale implementation of carbon-based materials in CCU.
Fabrication and Microwave Absorption Performance of FexOy/TiO2/C Composites Derived from Red Mud
Red mud, an industrial solid waste from alumina production, poses severe environmental challenges. This study presents a resource-efficient strategy to convert red mud into high-performance microwave absorbing materials. FexOy/TiO2/C composites were synthesized via a sol-gel method using starch as carbon source, followed by carbothermal reduction. The phase composition and microstructure were optimized by adjusting calcination temperature and raw material ratio. The optimal sample, RmCT-5.4-700, exhibited a minimum reflection loss (RLmin) of -30.2 dB at 14.0 GHz with an effective absorption bandwidth (EAB) of 5.3 GHz at a coating thickness of 2.0 mm. The superior absorption performance is attributed to the synergistic effects of dielectric components (TiO2, graphitized carbon) and magnetic components (Fe3O4/Fe). Carbothermal reduction introduces defects that induce dipole polarization, while the conductive network formed by graphitized carbon and Fe3O4/Fe particles enhances conductive loss. Heterogeneous interfaces between Fe3O4, Fe, TiO2, and the red mud matrix promote interfacial polarization. The magnetic loss of Fe3O4/Fe improves impedance matching, facilitating electromagnetic wave penetration and absorption. This work not only provides a novel route for red mud valorization but also contributes to the high-value utilization of solid wastes.
Damage Mechanism of High Chromia Refractory in the Slag Tapping Hole of Commercial Entrained-Flow Gasifiers
The service life of refractory bricks in the slag tapping hole of entrained-flow gasifiers is a critical bottleneck for long-term stable operation. This study investigated the damage mechanism of high chromia refractories in four commercial coal-water slurry gasifiers by analyzing gasification coal samples and corroded refractory bricks. Slag characteristics, including crystallization and viscosity-temperature behavior, were evaluated. Results revealed that low-viscosity slag induces more severe refractory damage. To mitigate slag crystallization risk, a safe slag tapping temperature range is recommended as tICT−t2.5 when tICT exceeds t25. Interior morphology of corroded bricks exhibited cracks, primarily attributed to molten slag penetration and subsequent reactions with refractory material. SEM-EDS analysis of slag-aggregate and slag-matrix interfaces identified reduction in Cr2O3 content as the earliest damage characteristic. XRD detected no zirconium-containing spinel in cracks, indicating that thermal expansion mismatch between newly formed phases and the refractory matrix drives crack propagation. A damage mechanism is proposed: initial Cr2O3 depletion compromises both matrix and aggregate, facilitating slag ingress and new phase formation, ultimately leading to structural failure. Early detection or prevention of Cr2O3 reduction is essential to prolong refractory service life.
Research advances in the pyrolysis recycling of waste wind turbine blades
The global energy landscape is undergoing a profound transformation, with wind energy gaining increasing prominence due to its clean and renewable nature. However, as installed wind power capacity expands, disposal of waste wind turbine blades (WWTB) has emerged as a significant challenge. These blades are predominantly composed of epoxy resin (EP) polymers, carbon fibers (CFs), and glass fibers (GFs). Improper disposal exacerbates environmental concerns and leads to loss of valuable resources, particularly carbon-based materials. Pyrolysis technology, a versatile and environmentally sustainable method for resource recovery, has garnered considerable attention for WWTB disposal. This work presents a comprehensive review of pyrolytic recycling of WWTB, focusing on principles and classifications of pyrolysis technology, key factors influencing the pyrolysis process, as well as pyrolysis methods, equipment, products, and their applications. Through in-depth analysis of current research, this review identifies critical unresolved issues and provides a forward-looking perspective on emerging research trends. The review highlights that pyrolysis can effectively recover glass fibers and carbon fibers with mechanical property retention depending on process conditions, and that catalytic pyrolysis can enhance the quality of recovered products. Economic analysis indicates that collaborative disposal methods can improve cost-effectiveness. Future research should focus on optimizing process parameters for large-scale industrial application and developing more efficient catalysts to improve product selectivity and fiber quality.
Citric Acid-Modified HUSY Zeolite Catalyzes Alkylation of Phenol with Cyclohexanol for High-Density Aviation Fuel Precursors
Lignin-derived oxygenated aromatics, particularly phenols and aromatic ethers, are promising feedstocks for synthesizing high-density, high-heat-sink aviation fuels via alkylation-hydrogenation processes. This study systematically evaluates the catalytic performance of various zeolites (Hβ, HZSM-5, MCM-41, and HUSY) in the alkylation of phenol with cyclohexanol. Characterization demonstrates that HUSY zeolite exhibits superior catalytic activity due to its favorable pore architecture and well-balanced acid site distribution, which synergistically facilitate molecular diffusion and catalytic transformations. To further enhance catalytic properties, HUSY was modified with citric acid at various concentrations and compared with NaOH and oxalic acid treatments. Results reveal that citric acid treatment preserves crystallinity while modulating acidity and pore structure. All modified zeolites enhance phenol alkylation activity. Notably, HUSY-0.5M, exhibiting the highest medium-strong acid to total acid ratio, achieves superior performance: 80.4% phenol conversion and 99.6% selectivity for alkylation products. The catalyst also shows high activity for various lignin-derived compounds (p-cresol, anisole, guaiacol), demonstrating broad applicability. This work provides a new strategy for valorizing lignin-derived phenols into high-value fuel precursors through alkylation.
Hydrogen Production and Structure Evolution Mechanism during Thermochemical Conversion of Microalgae Pellet in Molten Hydroxide Salts
This study investigates the thermochemical conversion behavior of microalgae pellets in a molten hydroxide salt (80% NaOH-20% Na2CO3) system and its influence on hydrogen production. By comparing temperature evolution, gas release characteristics, and structural evolution of pellets with and without molten salt, and integrating char alkalization experiments, the regulatory mechanism of molten salt on reaction pathways and hydrogen production was systematically analyzed. Results indicate that molten salt significantly enhances internal heat transfer efficiency, achieving a central heating rate of 177 °C/s, effectively alleviating thermal hysteresis. Concurrently, molten salt promotes pore development through penetration, erosion, and catalytic effects, resulting in a porosity increase of 53.2%–104.3% after 10 s of reaction. Conversion efficiency is markedly improved, with the dominant reaction pathway shifting to char alkalization after only 70 s. Furthermore, when heating rate is increased above 600 °C, hydrogen yield from char alkalization improves more significantly, primarily attributed to the synergistic promotion of molten salt catalysis and rapid heating on volatiles reforming. This study provides a theoretical foundation for understanding efficient hydrogen production from biomass in molten hydroxide salts.