Effects of Na and Na/CO2 Synergism on Gas/Tar Production During Rapid Coal Pyrolysis
Source abstract
Abstract
Coal pyrolysis and gasification are among the key technologies for the clean and efficient utilization of coal. This work examined the individual and synergistic effects of Na and CO2 on gas/tar generation during rapid coal pyrolysis using a fixed-bed reactor integrated with gas chromatography–mass spectrometry (GC-MS) and a flue gas analyzer. Key findings reveal that Na, CO2, and Na/CO2 synergism increased total gas volume by 671 vol.%, 772 vol.%, and 667 vol.%, respectively, while reducing tar yields by 4.14%, 3.12%, and 7.15%. Light oil yields reached 27.18%, 27.93%, and 40.35% under corresponding conditions. Crucially, Na significantly enhanced CO and CH4 release (dose-dependent), with low-concentration Na (1–3%) promoting light-component condensation versus high-concentration Na (5%) facilitating heavy-component cracking. Na/CO2 synergism intensified heavy-component fragmentation (efficacy increasing with Na loading), while low-concentration Na (1–3%) substantially boosted CO yield, highlighting its potential for selective syngas modulation. This work plays a pivotal role in advancing the low-emission, high-efficiency utilization of coal energy, aligning with global carbon reduction strategies.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Thermochemical Biomass Conversion Processes · Iron and Steelmaking Processes · Coal Combustion and Slurry Processing
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Xinjiang Xinye State-Owned Property Management (Group) Co., Ltd., Urumqi 830026, China
State Key Laboratory of Chemistry and Utilization of Carbon-Based Energy Resource, Xinjiang University, Urumqi 830017, China
Xinjiang Key Laboratory of Coal Clean Conversion & Chemical Engineering, College of Chemical Engineering, Xinjiang University, Urumqi 830017, China
Funding
Major Science and Technology Projects of Xinjiang Uygur Autonomous Region · National Natural Science Foundation of China · Special Project of State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources · Tianshan Innovation Team Plan of Xinjiang Uygur Autonomous Region
References (36)
Show source-provided references
1. Effect of metal elements in coal ash on NO release characteristics during oxy-fuel combustion at high temperature10.1016/j.joei.2020.11.005 ↗
2. Influence Mechanism of Water-Soluble Sodium on Zhundong Coal Pyrolysis10.1021/acsomega.1c07311 ↗
3. Liang, D., Xie, Q., Wei, Z., Wan, C., Li, G., and Cao, J. (2019). Transformation of alkali and alkaline earth metals in Zhundong coal during pyrolysis in an entrained flow bed reactor. J. Anal. Appl. Pyrolysis, 142.10.1016/j.jaap.2019.104661 ↗
4. Dynamic behavior of sodium release from pulverized coal combustion by phase-selective laser-induced breakdown spectroscopy10.1016/j.proci.2014.07.016 ↗
5. Liu, N., Huang, H., Feng, J., Li, R., Huang, X., and Wu, Y. (2025). Effects of alkali and alkaline earth metals in biomass on co-pyrolysis characteristics and product distribution of coal and biomass. Fuel, 389.10.1016/j.fuel.2025.134551 ↗
6. Effects of alkali and alkaline earth metals on the formation of light aromatic hydrocarbons during coal pyrolysis10.1016/j.jaap.2016.10.001 ↗
7. Influence of Structural Properties of Al2O3; on Alkali Metal Adsorption and Catalytic Tar Cracking Performance during High-Temperature Co-Pyrolysis of Coal and Biomass
8. Kong, L., Bai, J., and Li, W. (2021). Viscosity-temperature property of coal ash slag at the condition of entrained flow gasification: A review. Fuel Process. Technol., 215.10.1016/j.fuproc.2021.106751 ↗
9. He, Q., Xu, J., Jiang, X., Wang, C., Jiang, M., Wei, Y., Jiang, L., Xu, K., Wang, Y., and Su, S. (2023). Effects of AAEMs on the char heterogeneous structure evolution during Zhundong coal pyrolysis: Insights from micro-Raman spectroscopy. Fuel, 347.10.1016/j.fuel.2023.128378 ↗
10. Investigation on the effects of different forms of sodium, chlorine and sulphur and various pretreatment methods on the deposition characteristics of Na species during pyrolysis of a Na-rich coal10.1016/j.fuel.2018.07.130 ↗
11. Catalytic effect of sodium components on the microstructure and steam gasification of demineralized Shengli lignite char10.1016/j.ijhydene.2017.01.077 ↗
12. Zhao, Y., Xing, C., Shao, C., Chen, G., Sun, S., Chen, G., Zhang, L., Pei, J., Qiu, P., and Guo, S. (2020). Impacts of intrinsic alkali and alkaline earth metals on chemical structure of low-rank coal char: Semi-quantitative results based on FT-IR structure parameters. Fuel, 278.10.1016/j.fuel.2020.118229 ↗
13. Hydrogen and syngas production from catalytic steam gasification of char derived from ion-exchangeable Na- and Ca-loaded coal10.1016/j.ijhydene.2018.04.055 ↗
14. Microwave-assisted metal-catalyzed pyrolysis of low-rank coal: Promising option towards obtaining high-quality products10.1016/j.joei.2020.01.022 ↗
15. Li, Y.N. (2022). Study on Na/Ca-Catalyzed Coal Pyrolysis Characteristics and Tar Product Regulation. [Master’s Thesis, Shenyang Aerospace University].
16. Analysis of coal tar derived from pyrolysis at different atmospheres10.1016/j.fuel.2010.06.041 ↗
17. Strategic use of CO2 for co-pyrolysis of swine manure and coal for energy recovery and waste disposal10.1016/j.jcou.2017.09.018 ↗
18. Strategic CO2 utilization for shifting carbon distribution from pyrolytic oil to syngas in pyrolysis of food waste10.1016/j.jcou.2017.05.017 ↗
19. Tar formation during coal pyrolysis under N2 and CO2 atmospheres at elevated pressures10.1016/j.jaap.2016.01.009 ↗
20. Effects of CO2 on gas evolution and char structure formation during lump coal pyrolysis at elevated pressures10.1016/j.jaap.2013.08.003 ↗
21. Separation and Composition Analysis of GC/MS Analyzable and Unanalyzable Parts from Coal Tar10.1021/acs.energyfuels.8b01054 ↗
22. (2008). Proximate Analysis of Coal (Standard No. GB/T212-2008).
23. Microwave-assisted gasification of rice straw pyrolytic biochar promoted by alkali and alkaline earth metals10.1016/j.jaap.2015.02.001 ↗
24. Liu, M., Li, X., Wang, X., Bai, J., Kong, L., Bai, Z., Li, J., Li, H., Xing, L., and Li, W. (2022). Insights into the effect of particle size on coal char particle gasification by thermogravimetric analyzer and high temperature stage microscope. Fuel, 313.10.1016/j.fuel.2021.123010 ↗
25. Effect of volatile reactions on the yield and quality of tar from pyrolysis of Shenhua bituminous coal10.1016/j.jaap.2019.04.009 ↗
26. Relation between char structures and formation of volatiles during the pyrolysis of Shenfu coal: Further understanding on the effects of mobile phase and fixed phase10.1016/j.fuproc.2018.07.022 ↗
27. Wu, D., Dong, H., Luan, J., Du, Q., Gao, J., Feng, D., Zhang, Y., Zhao, Z., and Li, D. (2023). Reaction Molecular Dynamics Study on the Mechanism of Alkali Metal Sodium at the Initial Stage of Naphthalene Pyrolysis Evolution. Energies, 16.10.3390/en16176186 ↗
28. Detailed Investigation on Sodium (Na) Species Release and Transformation Mechanism during Pyrolysis and Char Gasification of High-Na Zhundong Coal10.1021/acs.energyfuels.7b00410 ↗
29. Roles of Ion-Exchangeable Sodium in the Conversion Process of Tar to Soot during Rapid Pyrolysis of Two Brown Coals in a Drop-Tube Reactor10.1021/acsomega.9b03441 ↗
30. Lu, Q., Guo, R., Zhang, H., Wang, J.-P., Lu, T., Li, G.-Y., and Liang, Y.-H. (2022). To stimulate, and to inhibit: A theoretical understanding of the sodium-catalytic mechanism of coke gasification. Chem. Eng. J., 435.10.1016/j.cej.2022.135091 ↗
31. Zhao, Z., Jin, J., Du, Q., Li, D., Gao, J., Dong, H., Zhang, Y., Wu, D., and Yang, X. (2025). The synergistic influence mechanism of the alkali metal sodium and CO2 on coal rapid pyrolysis soot: Experiments and DFT calculations. Fuel, 382.10.1016/j.fuel.2024.133294 ↗
32. Pyshyev, S., Korchak, B., Miroshnichenko, D., Lebedev, V., Yasinska, A., and Lypko, Y. (2025). Obtaining New Materials from Liquid Pyrolysis Products of Used Tires for Waste Valorization. Sustainability, 17.10.3390/su17093919 ↗
33. Effect of Coal Interaction on Coke Strength10.2355/tetsutohagane1955.87.5_238 ↗
34. Effect of Na on the condensation reaction of naphthalene molecules during coal pyrolysis10.1016/j.joei.2021.06.018 ↗
35. Xu, M., Wang, R., Fu, H., Shi, Y., and Ling, L. (2024). Harmonizing the cyano-group and Na to enhance selective photocatalytic O2 activation on carbon nitride for refractory pollutant degradation. Proc. Natl. Acad. Sci. USA, 121.10.1073/pnas.2318787121 ↗
36. Yao, R., Wei, J., Ge, Q., Xu, J., Han, Y., Ma, Q., Xu, H., and Sun, J. (2021). Monometallic iron catalysts with synergistic Na and S for higher alcohols synthesis via CO2 hydrogenation. Appl. Catal. B, 298.10.1016/j.apcatb.2021.120556 ↗