Performance and emission characteristics of an ammonia/diesel dual-fuel marine engine
(2023) In Renewable and Sustainable Energy Reviews 185.- Abstract
This study explores the challenges and possibilities of using ammonia (NH3) as a carbon-free fuel for marine propulsion in a Wärtsilä ammonia/diesel dual-fuel engine using a reactivity-controlled compression ignition (RCCI) concept. The main issues in ammonia RCCI engines are high ammonia slip and high emissions of nitrogen oxides and nitrous oxide. A joint experimental and computational investigation was conducted to understand the combustion process, pollutant and greenhouse gas (GHG) formation mechanisms, and the effects of injector configuration and injection timing on engine performance. A comparative assessment between the ammonia/diesel RCCI engine and a baseline natural gas/diesel RCCI engine showed that, upon... (More)
This study explores the challenges and possibilities of using ammonia (NH3) as a carbon-free fuel for marine propulsion in a Wärtsilä ammonia/diesel dual-fuel engine using a reactivity-controlled compression ignition (RCCI) concept. The main issues in ammonia RCCI engines are high ammonia slip and high emissions of nitrogen oxides and nitrous oxide. A joint experimental and computational investigation was conducted to understand the combustion process, pollutant and greenhouse gas (GHG) formation mechanisms, and the effects of injector configuration and injection timing on engine performance. A comparative assessment between the ammonia/diesel RCCI engine and a baseline natural gas/diesel RCCI engine showed that, upon replacing premixed natural gas with ammonia and maintaining the same energy share of diesel (8.5% of the total energy from diesel), the engine yielded considerably poor combustion efficiency. Increasing diesel usage to 24% share of the total energy allowed a successful engine operation, cutting GHG by 70%. However, higher diesel usage increased CO and CO2 emissions. N2O emission was attributed to the slow premixed ammonia/air flame propagation and near-wall flame quenching. The primary sources of NO emissions in ammonia/diesel RCCI engines were identified as fuel-NOx from premixed ammonia oxidation and thermal NOx in the diesel flame region. A recommendation was put forth for enhancing the operating conditions and injection strategies of ammonia RCCI engines. The proposed operation and injection strategy results in a 45% reduction in CO emission, a 60% reduction in total GHG emissions, and, notably, an 89% decrease in CO2 emissions compared to the LNG/diesel engine.
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- author
- Xu, Leilei LU ; Xu, Shijie LU ; Bai, Xue Song LU ; Repo, Juho Aleksi ; Hautala, Saana and Hyvönen, Jari
- organization
- publishing date
- 2023-10
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Ammonia, Decarbonization, Greenhouse gases (GHG), Marine engine, Reactivity-controlled compression ignition (RCCI)
- in
- Renewable and Sustainable Energy Reviews
- volume
- 185
- article number
- 113631
- publisher
- Elsevier
- external identifiers
-
- scopus:85168599221
- ISSN
- 1364-0321
- DOI
- 10.1016/j.rser.2023.113631
- language
- English
- LU publication?
- yes
- id
- 61663bae-3ea2-4fb0-8c48-d2687449e97e
- date added to LUP
- 2023-10-24 11:09:56
- date last changed
- 2023-11-07 15:40:22
@article{61663bae-3ea2-4fb0-8c48-d2687449e97e, abstract = {{<p>This study explores the challenges and possibilities of using ammonia (NH<sub>3</sub>) as a carbon-free fuel for marine propulsion in a Wärtsilä ammonia/diesel dual-fuel engine using a reactivity-controlled compression ignition (RCCI) concept. The main issues in ammonia RCCI engines are high ammonia slip and high emissions of nitrogen oxides and nitrous oxide. A joint experimental and computational investigation was conducted to understand the combustion process, pollutant and greenhouse gas (GHG) formation mechanisms, and the effects of injector configuration and injection timing on engine performance. A comparative assessment between the ammonia/diesel RCCI engine and a baseline natural gas/diesel RCCI engine showed that, upon replacing premixed natural gas with ammonia and maintaining the same energy share of diesel (8.5% of the total energy from diesel), the engine yielded considerably poor combustion efficiency. Increasing diesel usage to 24% share of the total energy allowed a successful engine operation, cutting GHG by 70%. However, higher diesel usage increased CO and CO<sub>2</sub> emissions. N<sub>2</sub>O emission was attributed to the slow premixed ammonia/air flame propagation and near-wall flame quenching. The primary sources of NO emissions in ammonia/diesel RCCI engines were identified as fuel-NO<sub>x</sub> from premixed ammonia oxidation and thermal NO<sub>x</sub> in the diesel flame region. A recommendation was put forth for enhancing the operating conditions and injection strategies of ammonia RCCI engines. The proposed operation and injection strategy results in a 45% reduction in CO emission, a 60% reduction in total GHG emissions, and, notably, an 89% decrease in CO<sub>2</sub> emissions compared to the LNG/diesel engine.</p>}}, author = {{Xu, Leilei and Xu, Shijie and Bai, Xue Song and Repo, Juho Aleksi and Hautala, Saana and Hyvönen, Jari}}, issn = {{1364-0321}}, keywords = {{Ammonia; Decarbonization; Greenhouse gases (GHG); Marine engine; Reactivity-controlled compression ignition (RCCI)}}, language = {{eng}}, publisher = {{Elsevier}}, series = {{Renewable and Sustainable Energy Reviews}}, title = {{Performance and emission characteristics of an ammonia/diesel dual-fuel marine engine}}, url = {{http://dx.doi.org/10.1016/j.rser.2023.113631}}, doi = {{10.1016/j.rser.2023.113631}}, volume = {{185}}, year = {{2023}}, }