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Hydrogen production from ammonia-rich combustion for fuel reforming under high temperature and high pressure conditions

Liu, Wei and Qi, Yunliang and Zhang, Ridong and Zhang, Qihang and Wang, Zhi (2022) Hydrogen production from ammonia-rich combustion for fuel reforming under high temperature and high pressure conditions. Fuel, 327 . Art. No. 124830. ISSN 0016-2361. doi:10.1016/j.fuel.2022.124830.

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Ammonia is a promising carbon-free fuel for internal combustion engines. However, the low reactivity and combustion sluggishness make ammonia difficult to be used in a single-fuel way. A small amount of hydrogen addition has been demonstrated beneficial to improving ammonia’s reactivity and engine performance. To overcome the safety and cost issues of onboard hydrogen storage on vehicles, we propose to produce hydrogen by in-cylinder ammonia reforming through ammonia-rich combustion. This paper presents an investigation on the hydrogen production from ammonia-rich combustion on a rapid compression machine (RCM) over conditions with varying pressures (22–36 bar), temperatures (1200–1300 K), and equivalence ratios (1.75–2.25). Both major combustion reactants (NH3) and products (H₂ and N₂) were analyzed using a fast sampling system and gas chromatography (GC). Chemical analysis was also conducted to interpret the experimental results. The results showed that current ammonia mechanisms were inadequate to predict the ignition delay time and the hydrogen production trend under engine-relevant and fuel-rich conditions. The experimental hydrogen production increased with the increasing initial temperature, which could be ascribed to the increase in reaction rate constants of key reactions. For the effect of pressure, the hydrogen production was found to first increase and then decrease as the initial pressure increased, which failed to be predicted by simulations. In the tested equivalence ratio range, a moderate fuel-rich equivalence ratio of two produced the highest hydrogen, in which the combined impact of key radical pool buildup (NH₃ and NH₂) and the change in reaction ratios of key reactions (NH₂ + H->NH + H₂) was responsible.

Item Type:Article
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URLURL TypeDescription
Qi, Yunliang0000-0003-4718-5025
Wang, Zhi0000-0001-5932-9124
Additional Information:© 2022 Elsevier. Received 30 January 2022, Revised 22 May 2022, Accepted 6 June 2022, Available online 6 July 2022, Version of Record 6 July 2022. This study was supported by the National Natural Science Foundation of China (Grant No.: 52076118). CRediT authorship contribution statement. Wei Liu: Methodology, Software, Investigation, Data curation, Formal analysis, Writing – original draft. Yunliang Qi: Validation, Methodology, Software, Formal analysis, Writing – review & editing. Ridong Zhang: Investigation, Writing – review & editing. Qihang Zhang: Writing – review & editing. Zhi Wang: Conceptualization, Supervision, Project administration. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Funding AgencyGrant Number
National Natural Science Foundation of China52076118
Subject Keywords:Ammonia combustion; Hydrogen production; Sampling; Reaction ratio; Chemical path analysis
Record Number:CaltechAUTHORS:20220721-8155000
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Official Citation:Wei Liu, Yunliang Qi, Ridong Zhang, Qihang Zhang, Zhi Wang, Hydrogen production from ammonia-rich combustion for fuel reforming under high temperature and high pressure conditions, Fuel, Volume 327, 2022, 124830, ISSN 0016-2361,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:115729
Deposited By: George Porter
Deposited On:22 Jul 2022 16:18
Last Modified:22 Jul 2022 16:19

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