Key Takeaways & Executive Findings
- •• • Blends mixing mode in CP-CRM increased tar yield by 35.29% relative to CP-N2, demonstrating a significant enhancement in liquid product yield for integrated coal-biomass pyrolysis. • • Blends mode yielded higher light oil content and lower pitch content in tar compared to layered modes (NMH/ELM and ELM/NMH), indicating improved tar quality with reduced heavy components. • • Phenols content in tar increased by 19.52% (Blends) and 33.27% (NMH/ELM) under CP-CRM versus CP-N2, showing that mixing mode and CRM atmosphere can selectively enhance valuable phenolic compounds. • • Free radical concentration in tar was lower under CP-CRM than CP-N2, suggesting that CRM-derived radicals effectively stabilize pyrolysis radicals, suppressing secondary reactions and improving process efficiency.
Abstract
The influence of mixing modes on the integrated process of co-pyrolysis of Naomaohu coal (NMH) and elm (ELM) with CO2 reforming of methane (CP-CRM) was investigated over Ni-based catalysts prepared by ball milling. Three mixing modes—NMH/ELM, ELM/NMH, and Blends—were examined and compared with co-pyrolysis under N2 (CP-N2). Results show that product distribution was significantly affected by mixing mode. The Blends mode achieved the highest tar yield, increasing by 35.29% compared with CP-N2. Light oil content in tar was higher, while pitch content was lower for Blends relative to layered modes. Phenols content in tar from Blends was 19.52% higher than CP-N2, and free radical concentration in tar was higher, attributed to enhanced heat and mass transfer between particles by mechanical mixing, promoting complete pyrolysis and efficient utilization of hydrogen-rich free radicals (·H, ·CHx) to suppress secondary cracking and polymerization. In contrast, NMH/ELM mode in CP-CRM improved phenols content by 33.27% over CP-N2. Free radical concentration in tar during CP-CRM was lower than in CP-N2, indicating timely stabilization of pyrolysis radicals by reforming-generated radicals. These findings provide guidance for regulating tar yield and composition in co-pyrolysis processes.
1. Introduction
Low-rank coal pyrolysis, while promising for Xinjiang's abundant reserves, suffers from low tar yield and heavy tar components due to low H/C ratio. Co-pyrolysis with biomass introduces hydrogen-rich radicals to stabilize coal-derived radicals, but biomass's high oxygen content reduces effective hydrogen transfer. Coupling with CO2 reforming of methane (CRM) offers an external source of hydrogen-rich radicals, yet the influence of physical mixing modes on this integrated process remains underexplored.
This study systematically compares three mixing configurations—layered NMH/ELM, layered ELM/NMH, and mechanical blending—under CP-CRM and CP-N2 atmospheres. By quantifying tar yield, composition, and free radical concentration, it identifies mechanical blending as optimal for enhancing heat and mass transfer, thereby maximizing tar yield and quality. These findings provide actionable insights for reactor design and process optimization in integrated coal-biomass pyrolysis with CRM.
Loading authentic research manuscript (Pages 1–5)...
LUO Jie, ZHANG Shuhao, ZHONG Mei, DAI Zhenghua, LIU Yang, JIN Lijun (2026). Effect of Mixing Modes on Integrated Process of Co-pyrolysis of Coal and Biomass with CO2 Reforming of Methane to Improve Tar Yield. Journal of Fuel Chemistry and Technology. https://doi.org/10.1016/S1872-5813(26)60648-2
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 optimal mixing mode for maximizing tar yield in the integrated CP-CRM process, and what is the quantitative improvement over conventional co-pyrolysis?
The Blends mode (mechanical mixing) achieved the highest tar yield, increasing by 35.29% compared with CP-N2. This improvement is attributed to enhanced heat and mass transfer between coal and biomass particles, promoting more complete pyrolysis and efficient radical interactions.
How does the mixing mode affect tar composition, particularly light oil and pitch fractions, under CP-CRM conditions?
Blends mode produced higher light oil content and lower pitch content compared to layered modes (NMH/ELM and ELM/NMH). This indicates that mechanical mixing favors the formation of lighter, more valuable fractions while suppressing heavy polymerization products.
What is the impact of CP-CRM on phenols content in tar compared to CP-N2, and which mixing mode yields the highest phenols enhancement?
Under CP-CRM, phenols content increased by 33.27% for NMH/ELM mode and 19.52% for Blends mode relative to CP-N2. The NMH/ELM mode showed the highest enhancement, suggesting that the spatial arrangement of coal and biomass layers influences phenol formation pathways.
How does the free radical concentration in tar vary between CP-CRM and CP-N2, and what does this indicate about reaction mechanisms?
Free radical concentration in tar was lower under CP-CRM than CP-N2, indicating that radicals generated during CRM (e.g., ·H, ·CHx) effectively stabilize pyrolysis-derived radicals, reducing their concentration in the final tar. This stabilization suppresses secondary cracking and polymerization, improving tar yield and quality.
What are the practical implications of these findings for scaling up the integrated co-pyrolysis and CRM process?
The results suggest that mechanical blending of coal and biomass is a simple yet effective method to enhance tar yield and quality in integrated CP-CRM processes. This can inform reactor design and operational strategies, potentially improving economic viability by increasing valuable liquid product yields.
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.