Hydrothermal liquefaction and gasification of Nannochloropsis sp.

Tylisha M. Brown, Peigao Duan, Phillip E. Savage

Research output: Contribution to journalArticlepeer-review

493 Scopus citations

Abstract

We converted the marine microalga Nannochloropsis sp. into a crude bio-oil product and a gaseous product via hydrothermal processing from 200 to 500 °C and a batch holding time of 60 min. A moderate temperature of 350 °C led to the highest bio-oil yield of 43 wt %. We estimate the heating value of the bio-oil to be about 39 MJ kg-1, which is comparable to that of a petroleum crude oil. The H/C and O/C ratios for the bio-oil decreased from 1.73 and 0.12, respectively, for the 200 °C product to 1.04 and 0.05, respectively, for the 500 °C product. Major bio-oil constituents include phenol and its alkylated derivatives, heterocyclic N-containing compounds, long-chain fatty acids, alkanes and alkenes, and derivatives of phytol and cholesterol. CO2 was always the most abundant gas product. H 2 was the second most abundant gas at all temperatures other than 500 °C, where its yield was surpassed by that of CH4. The activation energies for gas formation suggest the presence of gas-forming reactions other than steam reforming. Nearly 80% of the carbon and up to 90% of the chemical energy originally present in the microalga can be recovered as either bio-oil or gas products.

Original languageEnglish (US)
Pages (from-to)3639-3646
Number of pages8
JournalEnergy and Fuels
Volume24
Issue number6
DOIs
StatePublished - Jun 17 2010

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology

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