The catalytic pyrolysis of Nannochloropsis sp. was carried out in a bench-scale fixed bed reactor using hydration CaO catalyst. The effect of the hydration CaO dosage on pyrolysis product yield and bio-oil compositions was investigated. The regeneration characteristics of used CaO by mean of direct and intensified regeneration methods was also examined. The results showed that bio-oil quality improved significantly with increase of dosage. The bio-oil yield over the hydration CaO (mass ratio of catalyst to Nannochloropsis sp. was 1:3) was 28.5%

and it had low oxygen content

high calorific value

low kinetic viscosity

and low moisture content. Compared with direct pyrolysis oil

for the catalysis pyrolysis oil there were low contents of carboxylic compounds and hydroxyl compounds

and high content of aliphatic and aromatic hydrocarbons. The results from the regeneration experiments indicated that the catalytic activity was still higher for direct regeneration

and if water-washing intensified step was employed

leading to the significant improvement of bio-oil quality due to increase of the surface and calcium content.