Abstract: Clean and high-quality liquid fuels could be prepared from low-carbon olefins derived from refinery dry gas, liquefied petroleum gas and biomass or CO₂ conversion by the oligomerization reaction. ZSM-22 and ZSM-22-A, modified by tetraethylammonium hydroxide (TEAOH), were used as the catalysts, using ethylene as the representative of low-carbon olefin. Their effects on the synthesis of fuel oil from ethylene and the reaction conditions were investigated, respectively. The results showed that TEAOH modified ZSM-22-A exhibited higher catalytic activity than ZSM-22 due to its desilication, pore enlargement and increase of acid content. The optimum reaction conditions for this reaction were: a reaction temperature of 280 ℃, a reaction pressure of 5 MPa, and a mass space velocity of 0.15 - 1.35 h^-1 according to the oil target. It was found that ZSM-22 began to deactivate after 280 h of reaction, but ZSM-22-A did not deactivate after 400 h of reaction, so the ZSM-22-A had higher stability than ZSM-22, which indicated that the modification ZSM-22 with TEAOH had a good application prospect in the synthesis of liquid fuels by ethylene oligomerization.

Key words: ethylene, oligomerization, ZSM-22, modification, tetraethylammonium hydroxide, liquid fuel