Use of methanol as a promoter for ammonia combustion

Ruiz-Gutiérrez, A. (Universidad de Zaragoza) ; Diego, I. de ; Alzueta, M.U. (Universidad de Zaragoza)

Resumen: This work aims to study the oxidation of ammonia and methanol mixtures (NH3/CH3OH). For this purpose, laboratory experiments were conducted using a quartz flow reactor at atmospheric pressure, in a temperature range of 875–1425 K. The oxygen excess ratio (λ) and the NH3/CH3OH ratio were modified during the experiments. The experimental results have been simulated with a literature-based kinetic mechanism. The results show that the presence of CH3OH and the oxygen excess ratio affect the conversion of NH3, shifting its oxidation to lower temperatures as these variables increase. The oxidation of both fuels was slightly boosted with increasing CH3OH concentration. The λ study showed that the fuel-lean conditions accelerate NH3 oxidation at lower temperatures whereas do not have the same effect on CH3OH oxidation. The H radical concentration significantly influences fuel consumption, especially in reactions involving CH3OH and NH2, and it is also key for inhibition processes. CH3OH was found to initiate NH3 reactions, with strong competition for OH radicals between the two fuels. Nevertheless, methanol helps reduce ammonia's oxidation temperature. CH2OH was identified as the predominant species following H-abstraction from CH3OH. In the NH3/CH3OH ratio studies, increasing methanol concentration lowered the oxidation temperature of both fuels, with a temperature difference of up to 150 K observed for NH3/CH3OH ratios from 0.6 to 10. Increasing methanol concentration for a given NH3 value also shifted the prominence of secondary reaction pathways, further influencing the overall oxidation process.

Idioma: Inglés

DOI: 10.1016/j.biombioe.2024.107572

Año: 2025

Publicado en: BIOMASS & BIOENERGY 193 (2025), 107572 [11 pp.]
ISSN: 0961-9534

Financiación: info:eu-repo/grantAgreement/ES/AEI/PID2021–12432OB-I00
Financiación: info:eu-repo/grantAgreement/ES/DGA-FEDER/T22-23R
Financiación: info:eu-repo/grantAgreement/ES/MICINN PRE2022-104181
Financiación: info:eu-repo/grantAgreement/EUR/MICINN/TED2021-129557B-I00

Tipo y forma: Article (Published version)

Área (Departamento): Área Tecnologi. Medio Ambiente (Dpto. Ing.Quím.Tecnol.Med.Amb.)