Co-processing of bio-oils in FCC. Prediction of product distributions and coke yields

BERTERO, MELISA PAOLA; DE LA PUENTE, GABRIELA; ULISES SEDRAN

Cancún

Congreso; XX International Materials Research Congress; 2011

Sociedad Mexicana de Materiales

The co-processing of bio-oils from the pyrolysis of residual lignocellulosic biomass together with conventional feedstocks in the catalytic cracking of hydrocarbons (FCC) is an attractive option to convert biomass into fuels or petrochemical raw materials. By using present structure, no important process development and investments would be needed. However, the high concentration of oxygen in bio-oil and its high coke forming trend could hamper this possibility. Then, it is necessary to know the contribution to products and coke from the various species in bio-oil. The coke potential can be reduced to some extent with a thermal treatment. The conversion and product distribution from a laboratory bio-oil composed by eight different model compounds representing most important oxygenated functions in thermally treated bio-oils were studied. An equilibrium FCC catalyst was used and results were compared to thermal cracking reactions and the background from the behavior of individual model compounds under the same conditions. The mixture was made up of acetic acid, methyl acetate, furfural, 2-hidroxy-3-methylcyclopentenone, methanol, phenol, syringol, 1,2,4-trimethoxybenzene and water, with concentrations typical in bio-oils. A fixed bed reactor was used at 500 ºC and W/F0 0.16 h during 60 s.   The catalytic conversion and deoxygenation were very high (about 90 %) and much higher than those in the thermal experiments. In both cases the main products were hydrocarbons (aromatics and C2-C4 olefins with the catalyst; methane and C2-C4 olefins in the thermal experiments), water and oxygenated compounds. The yield of catalytic coke was very high (13.7 %wt.) and much higher than the yield of thermal coke (0.2 %wt.). This information is consistent with previous observations with individual reactants and may be useful in predicting the contributions from these types of compounds, significantly present in bio-oils, if they are to be co-processed in existing FCC units, or upgraded over acidic catalysts.