LAPSE:2023.29933
Published Article
LAPSE:2023.29933
An Experimental Study on the Characteristics of NOx Distributions at the SNCR Inlets of a Large-Scale CFB Boiler
April 14, 2023
Abstract
The unknown NOx distributions inside large-scale CFB (circulating fluidized bed) boilers have always hindered the economy of the SNCR (selective non-catalytic reduction) process. In this study, field tests were carried out on a typical 300 MW CFB boiler, where multi-level 316 L-made probe and Ecom-J2KN/Testo 350 analyzers were used to perform detailed two-dimensional distributions of flue gas composition at SNCR inlets for the first time. The penetration depth inside the horizontal flue pass was up to 7 m. The NOx distributions were analyzed in detail combining with the auxiliary test in the dilute phase zone. Key results show that the average O2 concentrations in #A and #C regions were 6.52% and 0.95%, respectively. The vertical NOx distributions of #A and #C SNCR inlets were similar, showing a trend of first increasing and then decreasing with peak value all appeared at 5 m depth, while the NOx distribution of #B SNCR inlet was basically increasing. Some local areas with extremely high NOx concentration (over 2000 mg/m3) were observed near the inclined edge of SNCR inlets, which has never been reported before. Based on this, the optimization of urea injections was conducted, which could save 15.7% of the urea solution consumption while ensuring ultra-low emission of NOx.
The unknown NOx distributions inside large-scale CFB (circulating fluidized bed) boilers have always hindered the economy of the SNCR (selective non-catalytic reduction) process. In this study, field tests were carried out on a typical 300 MW CFB boiler, where multi-level 316 L-made probe and Ecom-J2KN/Testo 350 analyzers were used to perform detailed two-dimensional distributions of flue gas composition at SNCR inlets for the first time. The penetration depth inside the horizontal flue pass was up to 7 m. The NOx distributions were analyzed in detail combining with the auxiliary test in the dilute phase zone. Key results show that the average O2 concentrations in #A and #C regions were 6.52% and 0.95%, respectively. The vertical NOx distributions of #A and #C SNCR inlets were similar, showing a trend of first increasing and then decreasing with peak value all appeared at 5 m depth, while the NOx distribution of #B SNCR inlet was basically increasing. Some local areas with extremely high NOx concentration (over 2000 mg/m3) were observed near the inclined edge of SNCR inlets, which has never been reported before. Based on this, the optimization of urea injections was conducted, which could save 15.7% of the urea solution consumption while ensuring ultra-low emission of NOx.
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Keywords
large-scale CFB, NOx distribution, SNCR, urea optimization
Subject
Suggested Citation
Yan J, Lu X, Zhang C, Li Q, Wang J, Liu S, Zheng X, Fan X. An Experimental Study on the Characteristics of NOx Distributions at the SNCR Inlets of a Large-Scale CFB Boiler. (2023). LAPSE:2023.29933
Author Affiliations
Yan J: College of Energy and Power Engineering, Nanjing Institute of Technology, Nanjing 211167, China; Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing 400044, China [ORCID]
Lu X: Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing 400044, China
Zhang C: College of Energy and Power Engineering, Nanjing Institute of Technology, Nanjing 211167, China; Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, China
Li Q: College of Energy and Power Engineering, Nanjing Institute of Technology, Nanjing 211167, China; Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, China
Wang J: Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, China
Liu S: Datang Wu’an Power Plant Co. Ltd., Handan 056300, China
Zheng X: Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing 400044, China
Fan X: Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing 400044, China
Lu X: Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing 400044, China
Zhang C: College of Energy and Power Engineering, Nanjing Institute of Technology, Nanjing 211167, China; Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, China
Li Q: College of Energy and Power Engineering, Nanjing Institute of Technology, Nanjing 211167, China; Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, China
Wang J: Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, China
Liu S: Datang Wu’an Power Plant Co. Ltd., Handan 056300, China
Zheng X: Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing 400044, China
Fan X: Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing 400044, China
Journal Name
Energies
Volume
14
Issue
5
First Page
1267
Year
2021
Publication Date
2021-02-25
ISSN
1996-1073
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PII: en14051267, Publication Type: Journal Article
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LAPSE:2023.29933
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https://doi.org/10.3390/en14051267
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