Nitrogen Oxides and Ammonia Removal Analysis Based on Three-Dimensional Ammonia-Diesel Dual Fuel Engine Coupled with One-Dimensional SCR Model

Xingyu Sun, Mengjia Li (), Jincheng Li (), Xiongbo Duan, Can Wang, Weifan Luo, Haifeng Liu () and Jingping Liu
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Xingyu Sun: College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China
Mengjia Li: State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
Jincheng Li: State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
Xiongbo Duan: School of Energy Science and Engineering, Central South University, Changsha 410083, China
Can Wang: State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
Weifan Luo: State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
Haifeng Liu: State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
Jingping Liu: College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China

Energies, 2023, vol. 16, issue 2, 1-18

Abstract: Ammonia, as an alternative fuel for internal combustion engines, can achieve nearly zero carbon emissions. Although the development of the pure ammonia engine is limited by its poor combustion characteristics, ammonia–hydrocarbon mixed combustion can effectively improve the combustion of ammonia fuel. With the increase in the ammonia fuel proportion in the fuel mixture, a large number of nitrogen oxides (NO X ) and unburned ammonia may be discharged, which have a poor impact on the environment. In this study, the performance of selective catalytic reduction (SCR) aftertreatment technology in reducing NO X and ammonia emissions from ammonia–diesel dual-fuel engines was investigated using simulation. A good cross-dimensional model was established under the coupling effect, though the effect of a single-dimensional model could not be presented. The results show that when the exhaust gas in the engine cylinder is directly introduced into the SCR without additional reducing agents such as urea, unburned ammonia flowing into SCR model is in excess, and there will be only ammonia at the outlet; however, if the unburned ammonia fed into the SCR model is insufficient to reduce NO, the ammonia concentration at the outlet will be 0. NO X can be 100% effectively reduced to N 2 under most engine conditions; thus, unburned ammonia in exhaust plays a role in reducing NO X emissions from ammonia–diesel dual-fuel engines. However, when the concentration of unburned ammonia in the exhaust gas of an ammonia–diesel dual-fuel engine is large, its ammonia emissions are still high even after the SCR. In addition, the concentrations of N 2 O after SCR do not decrease, but increase by 50.64 in some conditions, the main reason for which is that by the action of the SCR catalyst, NO 2 is partially converted into N 2 O, resulting in an increase in its concentration at the SCR outlet. Adding excessive air or oxygen into the SCR aftertreatment model can not only significantly reduce the ammonia concentration at the outlet of the model without affecting the NO X conversion efficiency of SCR, but inhibit N 2 O production to some extent at the outlet, thus reducing the unburned ammonia and NO X emissions in the tail gas of ammonia–diesel dual-fuel engines at the same time without the urea injection. Therefore, this study can provide theoretical guidance for the design of ammonia and its mixed-fuel engine aftertreatment device, and provide technical support for reducing NO X emissions of ammonia and its mixed fuel engines.

Keywords: ammonia–diesel dual-fuel engines; nitrogen oxides emissions; selective catalytic reduction (SCR); without the urea (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (5)

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