Quality improvement of pyrolysis oils
The quality of the oils obtained by pyrolysis of biomass is not good enough for their use as a fuel at a commercial level. The possibility of improving the quality of these oils by treatment under high pressure of hydrogen in the presence of a catalyst was evaluated. During the first stage of treatment, effected at around 230 C, the oil was stabilised and during the second stage at around 380 , the conversion was extended. When the oil was processed alone the oxygen content was reduced by 70% and the volatile fraction represented 50%. When the oil was coprocessed with a hydrogen donor solvent (Tetralin) HDO was 85% and volatility was 95%. The presence of a hydrogen donor helped to avoid the polymerisation to heavy compounds and the deactivation of the catalyst. The most active catalyst was NiMo supported on alumina and promoted by phosphore. A lesser but acceptable deoxygenation activity with low hydrogen consumption was obtained with a CoMo catalyst. Studies with model compounds showed that a complete deoxygenation of a previously hydrotreated oil can be obtained at 30 bar and 300 C, which are very mild conditions for a hydrotreatment. A number of analytical techniques were used in order to characterise the oil: IR and NMR spectroscopy, liquid and gas chromatography and mass spectrometry. The analysis showed that many substituted phenols and hydrocarbons comprising polyaromatic compounds were present in the oils.
Bibliographic Reference: EUR 12441 EN (1989) MF, 56 pp., ECU 4, blow-up copy ECU 7.50
Record Number: 198911178 / Last updated on: 1994-12-01
Original language: en
Available languages: en