Ammonia as an efficient COX-free hydrogen carrier: Fundamentals and feasibility analyses for fuel cell applications

Junyoung Cha, Young Suk Jo, Hyangsoo Jeong, Jonghee Han, SukWoo Nam, Kwang Ho Song, Chang Won Yoon

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

A COX-free 1 kW-class hydrogen power pack fueled by liquid ammonia is presented. For applications in a practical-scale hydrogen production system in conjunction with a polymer electrolyte membrane fuel cell, Ru catalysts supported on La-doped alumina (Ru/La(x)-Al2O3) were pelletized by varying the lanthanum doping content (x mol%) to control catalytic activities. An optimized Ru(1.06 wt%)/La(20)-Al2O3 pellet catalyst presents a >99.7% conversion efficiency at 500 °C under a gas hourly space velocity of 5000 mL gcat −1 h−1. Various materials were screened to remove residual ammonia from the product stream, and the X zeolite was chosen as a highly capable adsorbent. Based on the synthesized catalyst and screened adsorbent, a power pack consisting of a dehydrogenation reactor, an adsorbent tower, and a 1 kW-class polymer electrolyte membrane fuel cell was designed and manufactured. The as-integrated system can convert 9 L min−1 of ammonia into 13.4 L min−1 of hydrogen, powering a 1 kW-class fuel-cell continuously for >2 h without any performance degradation. To achieve autothermal and COX-free operations, heat required for ammonia dehydrogenation was provided by unutilized hydrogen from the fuel cell, drastically increasing the overall efficiency of the system to >49% while removing the external heat source, isobutane. Finally, a drone tethered to the system was operated, demonstrating the feasibility of an elongated flight time of >4 h, much longer than 14 min with Li-polymer battery loaded on the drone. The system is expected to meet the United States Department of Energy's 2020 gravimetric and volumetric hydrogen storage targets of 4.5 wt% and 30 gH2 L−1 at system weights of 43 kg and 50 kg, respectively.

Original languageEnglish
Pages (from-to)194-204
Number of pages11
JournalApplied Energy
Volume224
DOIs
Publication statusPublished - 2018 Aug 15

Fingerprint

fuel cell
Fuel cells
Ammonia
ammonia
hydrogen
Adsorbents
Hydrogen
Proton exchange membrane fuel cells (PEMFC)
Dehydrogenation
polymer
catalyst
electrolyte
Catalysts
membrane
Hydrogen storage
Lanthanum
Hydrogen production
Catalyst supports
Towers
Conversion efficiency

Keywords

  • Ammonia dehydrogenation
  • Carbon-free energy conversion
  • Catalysis
  • Energy storage
  • Fuel-cell
  • Hydrogen storage

ASJC Scopus subject areas

  • Building and Construction
  • Energy(all)
  • Mechanical Engineering
  • Management, Monitoring, Policy and Law

Cite this

Ammonia as an efficient COX-free hydrogen carrier : Fundamentals and feasibility analyses for fuel cell applications. / Cha, Junyoung; Jo, Young Suk; Jeong, Hyangsoo; Han, Jonghee; Nam, SukWoo; Song, Kwang Ho; Yoon, Chang Won.

In: Applied Energy, Vol. 224, 15.08.2018, p. 194-204.

Research output: Contribution to journalArticle

Cha, Junyoung ; Jo, Young Suk ; Jeong, Hyangsoo ; Han, Jonghee ; Nam, SukWoo ; Song, Kwang Ho ; Yoon, Chang Won. / Ammonia as an efficient COX-free hydrogen carrier : Fundamentals and feasibility analyses for fuel cell applications. In: Applied Energy. 2018 ; Vol. 224. pp. 194-204.
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