Synthesis of Oxygenates from Syngas on the CuO/ZnO/Al2O3 Catalyst: The Role of the Dehydrating Component

Resumo

The effect of the space velocity on the characteristics of bifunctional catalysts with different dehydrating components in the synthesis of methanol/dimethyl ether (DME) from syngas with a composition (vol %): CO 19.1, CO₂ 5.9, N₂ 5.5, H₂ (the rest) at 260°C and 3 MPa was studied. The commercial catalyst of methanol synthesis MegaMax 507 (CuO/ZnO/Al₂O₃) was used as the methanol component of the catalyst; the dehydrating agent was active gamma-alumina and quartz glass (for comparison), which is inert in methanol dehydration. At space velocities of less than 20 000 L(kg_cat h)^–1, the CO conversion and oxygenate productivity (based on C1) for the samples with alumina are higher than for the samples with quartz glass. The effect was explained by the fact that at partial conversion of methanol into DME, the rate of the reverse reaction of methanol with water decreases. This ultimately leads to an increase in the yield of methanol. The preferability of the one-stage synthesis over the two-stage synthesis in the production of oxygenates depends on the load on gas, the difference in the productivity passing through a maximum at increased load on gas.