Bifunctional Catalyst Capable of Directly Converting Syn-gas to Lower Olefins

The researchers at the Xiamen University have developed a designated bifunctional catalyst that contains some active components. Application of this catalyst can selectively convert syn-gas to lower olefns (C2—C4olefins), which would be very attractive to the chemical industry.

The silicon-substituted aluminophospahte SAPO-34 is an outstanding catalyst for MTO reaction. Adoption of the nano particles of zirconium oxide and zinc oxide in a ratio of 2:1 can achieve the catalysis of methanol synthesis with predominant production of lower olefns.

The combination of two components in the bifunctional catalyst is very important. The two components must be kept in close contact. However, a too close contact between these components would make the newly formed olefns easily reach the catalytic centers, resulting in the conversion of CO and hydrogen to methanol. Olefins can also be bound with hydrogen to lose their double bonds, leading to the formation of more paraffins. The best result was obtained after grinding the two catalysts to form a slurry. At a temperature of around 400 ℃ the selectivity of lower olefns (C2—C4olefins) on the bifunctional catalyst is 74% with the carbon monoxide conversion equating to around 11%, and these good results are favorable to the direct conversion of syngas to lower olefns.