Upgrading Bio-Oil by Catalytic Esterification

Abstract

Solid acid 40SiO2/TiO2-SO4 2- and solid base 30K2CO3/Al2O3-NaOH were prepared and compared on catalytic esterification activity according to model reaction. Upgrading of bio-oil by solid acid and solid base catalysts in the conditioned experiment was investigated, in which dynamic viscosities of bio-oil was lowered markedly, although 8 months aging did not showed much viscous, so as to improve its fluidity and enhance its stability positively. Even the dehydration by 3A molecular sieve still kept the fluidity well. The density of upgraded bio-oil was reduced from 1.24 kg/m3 to 0.96 kg/m3; gross calorific value increased by 50.7% and 51.8% respectively. The results of GC-MS analysis showed that esters reaction in the bio-oil were promoted by both solid acid and solid base catalysts, and solid acid converted volatile and nonvolatile organic acids into esters and raised their amount by twenty fold. Besides the catalytic esterification, solid acid carried out the carbonyl addition of alcohol to acetals. Some components of bio-oil undertook the isomerization over solid base catalyst.