Comparative analysis on pulverized coal combustion preheated by self-sustained purifying burner with coaxial and centrosymmetric air nozzle structures: Purification, combustion and NOx emission characteristics

doi:10.1016/j.cjche.2024.09.017

中国化学工程学报 ›› 2025, Vol. 77 ›› Issue (1): 102-113.DOI: 10.1016/j.cjche.2024.09.017

Comparative analysis on pulverized coal combustion preheated by self-sustained purifying burner with coaxial and centrosymmetric air nozzle structures: Purification, combustion and NO_x emission characteristics

Kun Su^1,2, Ziqu Ouyang^1,2, Hongshuai Wang^1,2, Hongliang Ding^1,2, Wenyu Wang^1,2, Qisi Chen^1,2, Shuyun Li^1,2

1. State Key Laboratory of Coal Conversion, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China;
2. University of Chinese Academy of Sciences, Beijing 100049, China

收稿日期:2024-06-22 修回日期:2024-09-03 接受日期:2024-09-03 出版日期:2025-01-28 发布日期:2024-10-20
通讯作者: Ziqu Ouyang,E-mail:ouyangziqu@iet.cn
基金资助:
Postdoctoral Fellowship Program of CPSF (GZC20232672), CAS Project for Young Scientists in Basic Research (YSBR-028) and the Strategic Priority Research Program (XDA29010200) are gratefully acknowledged.

Comparative analysis on pulverized coal combustion preheated by self-sustained purifying burner with coaxial and centrosymmetric air nozzle structures: Purification, combustion and NO_x emission characteristics

Kun Su^1,2, Ziqu Ouyang^1,2, Hongshuai Wang^1,2, Hongliang Ding^1,2, Wenyu Wang^1,2, Qisi Chen^1,2, Shuyun Li^1,2

1. State Key Laboratory of Coal Conversion, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China;
2. University of Chinese Academy of Sciences, Beijing 100049, China

Received:2024-06-22 Revised:2024-09-03 Accepted:2024-09-03 Online:2025-01-28 Published:2024-10-20
Contact: Ziqu Ouyang,E-mail:ouyangziqu@iet.cn
Supported by:
Postdoctoral Fellowship Program of CPSF (GZC20232672), CAS Project for Young Scientists in Basic Research (YSBR-028) and the Strategic Priority Research Program (XDA29010200) are gratefully acknowledged.

摘要/Abstract

摘要： To optimize secondary air nozzle structure in purifying burner, this study focused on the comparison of purification, combustion and NO_x emission characteristics of pulverized coal preheated by a 30 kW purifying burner with coaxial and centrosymmetric structures. Centrosymmetric structure shifted the position of main burning region down in high-temperature reduction unit (HTRU), and the number of branches differently influenced the temperature in different regions with this structure. For reductive gas components, CO concentration with centrosymmetric structure was higher compared to coaxial structure, while the differences in H₂ and CH₄ concentrations were smaller. Centrosymmetric structure was more disadvantageous to improve physicochemical properties of pulverized coal compared to coaxial structure, and this structure with four branches further deteriorated its properties compared to two branches. In mild combustion unit (MCU), the temperature at top was lower with centrosymmetric structure, while was higher in the rest. Centrosymmetric structure more effectively reduced NO_x emission compared to coaxial structure, but with slight sacrifice of combustion efficiency (η). Moreover, both two-branch and four-branch centrosymmetric structures realized ultra-low NO_x emission (<50 mg·m^-3) with high η of over 98.50%, and the former was more advantageous. With this optimal structure, η and NO_x emission were 99.25% and 40.42 mg·m^-3.

关键词: Purifying-burning, NO_x emission, Coaxial structure, Centrosymmetric structure

Abstract: To optimize secondary air nozzle structure in purifying burner, this study focused on the comparison of purification, combustion and NO_x emission characteristics of pulverized coal preheated by a 30 kW purifying burner with coaxial and centrosymmetric structures. Centrosymmetric structure shifted the position of main burning region down in high-temperature reduction unit (HTRU), and the number of branches differently influenced the temperature in different regions with this structure. For reductive gas components, CO concentration with centrosymmetric structure was higher compared to coaxial structure, while the differences in H₂ and CH₄ concentrations were smaller. Centrosymmetric structure was more disadvantageous to improve physicochemical properties of pulverized coal compared to coaxial structure, and this structure with four branches further deteriorated its properties compared to two branches. In mild combustion unit (MCU), the temperature at top was lower with centrosymmetric structure, while was higher in the rest. Centrosymmetric structure more effectively reduced NO_x emission compared to coaxial structure, but with slight sacrifice of combustion efficiency (η). Moreover, both two-branch and four-branch centrosymmetric structures realized ultra-low NO_x emission (<50 mg·m^-3) with high η of over 98.50%, and the former was more advantageous. With this optimal structure, η and NO_x emission were 99.25% and 40.42 mg·m^-3.

Key words: Purifying-burning, NO_x emission, Coaxial structure, Centrosymmetric structure

Kun Su, Ziqu Ouyang, Hongshuai Wang, Hongliang Ding, Wenyu Wang, Qisi Chen, Shuyun Li. Comparative analysis on pulverized coal combustion preheated by self-sustained purifying burner with coaxial and centrosymmetric air nozzle structures: Purification, combustion and NO_x emission characteristics[J]. 中国化学工程学报, 2025, 77(1): 102-113.

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Comparative analysis on pulverized coal combustion preheated by self-sustained purifying burner with coaxial and centrosymmetric air nozzle structures: Purification, combustion and NO_x emission characteristics

Comparative analysis on pulverized coal combustion preheated by self-sustained purifying burner with coaxial and centrosymmetric air nozzle structures: Purification, combustion and NO_x emission characteristics

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