Experimental Study on Two-Stage Modification, Combustion and NOx Emission Characteristics of Pulverized Coal in a Purification-Combustion Reaction System

  • SU Kun ,
  • OUYANG Ziqu ,
  • WANG Hongshuai ,
  • HU Yujie ,
  • DING Hongliang ,
  • ZHANG Jinyang ,
  • ZHU Shujun
Expand
  • 1. Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
    2. School of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
    3. School of Energy and Power Engineering, Jiangsu University, Zhenjiang 212013, China

Online published: 2025-07-04

Supported by

CAS Project for Young Scientists in Basic Research (YSBR-028), Youth Innovation Promotion Association (CAS2019148), and the Strategic Priority Research Program (XDA29010200) are gratefully acknowledged.

Copyright

Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2025

Abstract

To achieve deep NOx control, we investigated a purification-combustion system consisting of devolatilizer, swirl burner and down-fired combustor, and explored the influences of primary and secondary air ratios (λp and λ2) on two-stage modification, combustion and NOx emission of pulverized coal in a 30 kW purification-combustion experimental bench. In devolatilizer and swirl burner, the temperature in different positions increases with λp and λ2 rising. Moreover, the location of main burning zone in swirl burner could be changed by increasing λp rather than λ2. CO and H2 are the main burnable components in modified gases, and their concentrations decrease with λp and λ2 increasing. By contrast, the CH4 concentration is extremely low. Purification system composed of devolatilizer and swirl burner outperformed single-stage devolatilizer in increasing specific surface area, pore volume, pore diameter and fuel conversion rate of pulverized coal as well as improving its carbon microcrystalline structure, and these indexes of modified char are better and better with λp and λ2 increasing properly in this system. In down-fired combustor, as λp and λ2 increase, the temperature changes slightly in reduction region, while it decreases in complete combustion region only at lower λ2. Properly rising λp and λ2 will reduce the NOx emission with high efficiency of above 99.00%, but the emission reduction driven by λ2 is limited.

Cite this article

SU Kun , OUYANG Ziqu , WANG Hongshuai , HU Yujie , DING Hongliang , ZHANG Jinyang , ZHU Shujun . Experimental Study on Two-Stage Modification, Combustion and NOx Emission Characteristics of Pulverized Coal in a Purification-Combustion Reaction System[J]. Journal of Thermal Science, 2025 , 34(4) : 1483 -1496 . DOI: 10.1007/s11630-025-2108-3

References

[1] Tang X., Jin Y., Mclellan B., Wang J., Li S., China’s coal consumption declining—Impermanent or permanent. Resources Conservation and Recycling, 2018, 129: 307–313. 
[2] Tabar M., Anvari M., Lohmann G., Heinemann D., Wachter M., Milan P., Kolmogorov spectrum of renewable wind and solar power fluctuations. European Physical Journal-Special Topics, 2014, 223: 2637–2644.
[3] You C., Xu X., Coal combustion and its pollution control in China. Energy, 2010, 35: 4467–4472. 
[4] Yang Y., Zhang F., Yang S., Investigation and research on the treatment of air pollution by heating boiler of Beijing University of Chemical Technology. 6th International Conference on Advances in Energy Resources and Environment Engineering, 2021, 647: 012213. 
[5] Wang Z., Zhang J., Zhao Y., Zheng C., Relationship between nitrogenous species in coals and volatile nitrogen-containing yields during pyrolysis. Asia-Pacific Journal of Chemical Engineering, 2012, 7: 124–130. 
[6] Wang Y., Zhou Y., Bai N., Han J., Experimental investigation of the characteristics of NOx emissions with multiple deep air-staged combustion of lean coal. Fuel, 2020, 280: 118416. 
[7] Yang J., Sun R., Sun S., Zhao N., Hao N., Chen H., Experimental study on NOx reduction from staging combustion of high volatile pulverized coals. Part 2. Fuel staging. Fuel Processing Technology, 2015, 138: 445–454. 
[8] Yoshiie R., Hikosaka N., Nunome Y., Ueki Y., Naruse I., Effects of flue gas re-circulation and nitrogen contents in coal on NOx emissions under oxy-fuel coal combustion. Fuel Processing Technology, 2015, 136: 106–111. 
[9] Zhou W., Moyeda D., Payne R., Berg M., Application of numerical simulation and full scale testing for modeling low NOx burner emissions. Combustion Theory and Modelling, 2009, 13: 1053–1070. 
[10] Ouyang Z., Zhu J., Lyu Q., Experimental study on preheating and combustion characteristics of pulverized anthracite coal. Fuel, 2013, 113: 122–127. 
[11] Zhang X., Chen Z., Hou J., Liu Z., Zeng L., Li Z., Evaluation of wide-range coal combustion performance of a novel down-fired combustion technology based on gas-solid two-phase flow characteristics. Energy, 2022, 248: 123662. 
[12] Liu W., Ouyang Z., Cao X., Na Y., Liu D., Zhu S., Effects of secondary air velocity on NO emission with coal preheating technology. Fuel, 2019, 256: 115898. 
[13] Su K., Ouyang Z., Wang H., Zhang J., Ding H., Wang W., Research on purification, combustion and NOx emission characteristics of pulverized coal preheated by a novel self-sustained purifying burner. Fuel, 2024, 366: 131436. 
[14] Saxena S., Jotshi C., Fluidized-bed incineration of waste materials. Progress in Energy & Combustion Science, 1994, 20: 281–324. 
[15] Zhu T., Tang C., Ning X., Wang L., Deng L., Che D., Experimental study on NOx emission characteristics of Zhundong coal in cyclone furnace. Fuel, 2022, 311: 122536. 
[16] Lang T., Jensen A., Jensen P., Retention of organic elements during solid fuel pyrolysis with emphasis on the peculiar behavior of nitrogen. Energy & Fuels, 2005, 19: 1631–1643. 
[17] Wang P., Wang C., Wang C., Yuan M., Zhang J., Du Y., Investigation on co-gasification characteristics of semi-coke and bituminous coal in a CO2 atmosphere at high temperatures. Energy & Fuels, 2020, 34(12): 16132–16146. 
[18] Chen J., Chen G., Zhang A., Deng H., Wen X., Wang F., Numerical simulation of the effect of CH4/CO concentration on combustion characteristics of low calorific value syngas. ACS OMEGA, 2021, 6: 5754–5763.
[19] Thong C., Dally B., Birzer C., Kalt P., Hassan E., An experimental study on the near flow field of a round jet affected by upstream multi-lateral side-jet. Experimental Thermal and Fluid Science, 2017, 82: 198–211. 
[20] Xu T., Pisupati S., Bhattacharya S., Comparison of entrained flow CO2 gasification behaviour of three low-rank coals——Victorian brown coal, Beulah lignite, and Inner Mongolia lignite. Fuel, 2019, 249: 206–218. 
[21] Chen D., Bu C., Wang X., Zhang J., Kabayashi N., Piao G., Gasification and combustion kinetics of a high-ash-fusion-temperature coal using thermogravimetric analysis. Journal of Thermal Analysis and Calorimetry, 2020, 143: 3209–3220. 
[22] Wang Z., Chen Y., Qi Y., Wang R., Wang L., Jiang J., Experimental study of pore structure and fractal characteristics of pulverized intact coal and tectonic coal by low temperature nitrogen adsorption. Powder Technology, 2019, 350: 15–25. 
[23] Lee D., Bae J., Park S., Lee Y., Hong J., Choi Y., The pore structure variation of coal char during pyrolysis and its relationship with char combustion reactivity. Industrial & Engineering Chemistry Research, 2012, 51(42): 13580–13588. 
[24] Jiang X., Zheng C., Yan C., Liu D., Qiu J., Li J., Physical structure and combustion properties of super fine pulverized coal particle. Fuel, 2002, 81(6): 793–797. 
[25] Zhong S., Yue H., Baitalow F., Reinmoller M., Meyer B., In-situ investigation of coal particle fragmentation induced by thermal stress and numerical analysis of the main influencing factors. Energy, 2021, 215: 119138.
[26] Sheng C., Char structure characterised by Raman spectroscopy and its correlations with combustion reactivity. Fuel, 2007, 86: 2316–2324. 
[27] Kurose R., Matsuda H., Makino H., Suzuki A., Characteristics of particulate matter generated in pressurized coal combustion for high-efficiency power generation system. Advanced Powder Technology, 2003, 14: 673–694. 
[28] Yu J., Lucas J., Wall T., Formation of the structure of chars during devolatilization of pulverized coal and its thermoproperties: A review. Process in Energy and Combustion Science, 2007, 33: 135–170. 
[29] Courtemanche B., Levendis Y., A laboratory study on the NO, NO2, SO2, CO and CO2 emissions from the combustion of pulverized coal, municipal waste plastics and tires. Fuel, 1998, 77(3): 183–196. 
[30] Rong H., Suda T., Takafuji M., Hirata T., Sato J., Analysis of low NO emission in high temperature air combustion for pulverized coal. Fuel, 2004, 83(9): 1133–1141. 
[31] Dong C., Yang Y., Zhang J., Lu X., Gaseous emissions from the combustion of a waste mixture containing a high concentration of N2O. Waste Management, 2009, 29: 272–276.
Outlines

/