The study of ignition and emission characteristics of hydrogen-additive hydro-processed renewable diesel

Wei Cheng Wang, Jhe Kai Lin, Bo Han Huang, Xinwei Cheng*, Hiew Mun Poon*, Cho Yu Lee*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


This study was conducted to understand the effects of hydrogen (H2) addition on the combustion and emission characteristics of hydro-processed renewable diesel. Experiments were performed in a constant volume combustion chamber (CVCC) at varying H2 concentrations (0%, 5%, and 10% (by vol.)) relative to air (100%, 95%, and 90% (by vol.)), initial temperatures (Tini) of 600, 650 and 700 K, equivalence ratios (φ) of 0.5, 1.0, and 1.5 and a fixed initial pressure (Pini) of 10 bar. Overall, HRD has lower ignition delay (ID) and total ID. However, H2 addition to HRD delayed the fuel's auto-ignition due to excess H2 oxidation (H2+OH[dbnd]H2O + H) reaction taking place, which turns the chain reactions from branching to propagation, resulting from increasing in ID. Moreover, increasing of H2 concentrations enhanced the maximum pressure rise (Pmax) and heat release rate (HRR), whereas carbon dioxide (CO2) and unburned hydrocarbon (HC) were decreased due to the higher magnitude of the lower heating value of H2 than that of pure HRD. Since H2 itself is a carbon-free molecule, the carbon content of the fuel is reduced. H2 has the characteristics of fast combustion, resulting in a more flammable and complete mixture, which also makes HC emissions to become lower. However, the higher energy density of H2 significantly raises the combustion temperature, and subsequent nitrogen oxides (NOx) were increased. The kinetic modeling predictions revealed that the IDs for HRD-H2 were elongated due to the increased hydroperoxyl (HO2) and hydrogen peroxide (H2O2) mole fractions which led to improved stability.

Original languageEnglish
JournalInternational Journal of Hydrogen Energy
Early online date12 Jan 2023
Publication statusEarly online date - 12 Jan 2023

Bibliographical note

Funding Information:
This work was supported by the Ministry of Science and Technology (Taiwan) [grant number 109-2221-E-110-011- MY3 ; 110-2622-8-110 -002 ; 111-2222-E-006 -010 ].

Publisher Copyright:
© 2022 Hydrogen Energy Publications LLC


  • CVCC
  • Emissions
  • HRR
  • Hydrogen additive
  • Ignition delay
  • Kinetic modelling

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology


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