CATALYTIC COPROCESSING OF BIOMASS-DERIVED PYROLYSIS VAPORS AND METHANOL

Biomass in the form of wood waste was flash pyrolysed in a fluidised bed reactor at 550 degrees C. Methanol was injected into the top section of the fluidised bed reactor and the subsequent mixture of pyrolysis vapours and methanol were passed over a fixed bed of zeolite ZSM-5 catalyst held at 500 degrees C. The addition of methanol to the pyrolysis vapour stream was controlled using a high-performance liquid chromatography pump. The ratio of wood to methanol fed to the fluidised bed reactor was varied from 100:0 to 70:30 wood:methanol; a pure methanol experimental run was also carried out. The oil, aqueous, gaseous and coke products from the catalysis process were analysed using a number of analytical techniques. The elemental composition of all the products was determined. The gaseous products were identified and quantified using gas chromatography. The oils were analysed using size exclusion chromatography to determine their molecular weight range, and capillary gas chromatography/mass spectrometry was used to identify and quantify the individual components present in the oils. The presence of methanol during the catalytic upgrading of the pyrolysis vapours was found to increase the amount of oxygen expelled from the vapours as water. There was also a significant increase in the formation of alkylated aromatic hydrocarbon products.