Ga/HZSM-5 catalysed acetic acid ketonisation for upgrading of biomass pyrolysis vapours

Research output: Contribution to journalArticlepeer-review

Authors

  • Amin Osatiashtiani
  • Adam F. Lee
  • Karen Wilson

Colleges, School and Institutes

External organisations

  • Aston University
  • RMIT University
  • Cranfield University
  • Fraunhofer UMSICHT
  • Friedrich-Alexander University Erlangen-Nuremberg

Abstract

Pyrolysis bio-oils contain significant amounts of carboxylic acids which limit their utility as biofuels. Ketonisation of carboxylic acids within biomass pyrolysis vapours is a potential route to upgrade the energy content and stability of the resulting bio-oil condensate, but requires active, selective and coke-resistant solid acid catalysts. Here we explore the vapour phase ketonisation of acetic acid over Ga-doped HZSM-5. Weak Lewis acid sites were identified as the active species responsible for acetic acid ketonisation to acetone at 350 °C and 400 °C. Turnover frequencies were proportional to Ga loading, reaching ~6 min−1 at 400 °C for 10Ga/HZSM-5. Selectivity to the desired acetone product correlated with the weak:strong acid site ratio, being favoured over weak Lewis acid sites and reaching 30% for 10Ga/HZSM-5. Strong Brønsted acidity promoted competing unselective reactions and carbon laydown. 10Ga/HZSM-5 exhibited good stability for over 5 h on-stream acetic acid ketonisation.

Details

Original languageEnglish
Article number841
Pages (from-to)1-13
Number of pages13
JournalCatalysts
Volume9
Issue number10
Publication statusPublished - 11 Oct 2019

Keywords

  • Pyrolysis, Ketonisation, Bio-oil, Turnover frequencies (TOFs)