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Modeling of Ammonia Solution Spray and Mixing in Selective Catalytic Reduction (SCR) System

Xu, Shijie LU orcid ; Bai, Xue Song LU ; Li, Yaopeng LU ; Xu, Leilei LU ; Larsson, Peter LU and Tunestål, Per LU orcid (2019) 11th International Conference on Applied Energy, ICAE 2019 In Energy Proceedings 2.
Abstract

In this work, numerical simulation was carried out to study the injection and mixing of ammonia solution spray in the exhaust pipe of diesel engines. The ammonia solution was injected into the hot gas of 623 K. The spray was vaporized into gas and mixed with the hot exhaust gas and together the mixture was transported in the exhaust gas pipe downstream where a selective catalytic reduction (SCR) system was implemented to convert NOx to H2O and N2. The effects of exhaust pipe geometry and gravity on the droplet evolution and vapor mass fraction were investigated. The results show that the influence of gravity is negligible, while the exhaust pipe geometry has a great impact on the vapor distribution. In... (More)

In this work, numerical simulation was carried out to study the injection and mixing of ammonia solution spray in the exhaust pipe of diesel engines. The ammonia solution was injected into the hot gas of 623 K. The spray was vaporized into gas and mixed with the hot exhaust gas and together the mixture was transported in the exhaust gas pipe downstream where a selective catalytic reduction (SCR) system was implemented to convert NOx to H2O and N2. The effects of exhaust pipe geometry and gravity on the droplet evolution and vapor mass fraction were investigated. The results show that the influence of gravity is negligible, while the exhaust pipe geometry has a great impact on the vapor distribution. In straight pipe case the NOx reduction is only achievable in a small area of the catalyzer, which is in good agreement with the experiments. Analysis of the velocity field and streamlines shows that the ammonia vapor is blocked by a recirculation zone; as a result, the vapor mass fraction will be centralized into a small zone because radial component of vapor velocity is too slow to penetrate into the center of main flow. In addition, the spray droplet size distribution indicates that a certain amount of ammonia enters into catalyzer as liquid phase with medium diameter around 19 and 17 μm in straight and bending pipe, which further deteriorates the catalytic efficiency. The results provide a guidance for the design of ammonia injector and the exhaust pipe geometry.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
ammonia, exhaust gas after treatment, selective catalytic reduction
in
Energy Proceedings
volume
2
article number
73
pages
4 pages
publisher
Scanditale AB
conference name
11th International Conference on Applied Energy, ICAE 2019
conference location
Västerås, Sweden
conference dates
2019-08-12 - 2019-08-15
external identifiers
  • scopus:85202612519
DOI
10.46855/energy-proceedings-1514
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2019 ICAE.
id
cf19e22b-3183-4019-9489-8532cc1d9dba
date added to LUP
2024-10-02 11:06:41
date last changed
2025-04-04 14:03:02
@article{cf19e22b-3183-4019-9489-8532cc1d9dba,
  abstract     = {{<p>In this work, numerical simulation was carried out to study the injection and mixing of ammonia solution spray in the exhaust pipe of diesel engines. The ammonia solution was injected into the hot gas of 623 K. The spray was vaporized into gas and mixed with the hot exhaust gas and together the mixture was transported in the exhaust gas pipe downstream where a selective catalytic reduction (SCR) system was implemented to convert NO<sub>x</sub> to H<sub>2</sub>O and N<sub>2</sub>. The effects of exhaust pipe geometry and gravity on the droplet evolution and vapor mass fraction were investigated. The results show that the influence of gravity is negligible, while the exhaust pipe geometry has a great impact on the vapor distribution. In straight pipe case the NO<sub>x</sub> reduction is only achievable in a small area of the catalyzer, which is in good agreement with the experiments. Analysis of the velocity field and streamlines shows that the ammonia vapor is blocked by a recirculation zone; as a result, the vapor mass fraction will be centralized into a small zone because radial component of vapor velocity is too slow to penetrate into the center of main flow. In addition, the spray droplet size distribution indicates that a certain amount of ammonia enters into catalyzer as liquid phase with medium diameter around 19 and 17 μm in straight and bending pipe, which further deteriorates the catalytic efficiency. The results provide a guidance for the design of ammonia injector and the exhaust pipe geometry.</p>}},
  author       = {{Xu, Shijie and Bai, Xue Song and Li, Yaopeng and Xu, Leilei and Larsson, Peter and Tunestål, Per}},
  keywords     = {{ammonia; exhaust gas after treatment; selective catalytic reduction}},
  language     = {{eng}},
  publisher    = {{Scanditale AB}},
  series       = {{Energy Proceedings}},
  title        = {{Modeling of Ammonia Solution Spray and Mixing in Selective Catalytic Reduction (SCR) System}},
  url          = {{http://dx.doi.org/10.46855/energy-proceedings-1514}},
  doi          = {{10.46855/energy-proceedings-1514}},
  volume       = {{2}},
  year         = {{2019}},
}