Synthesis of Dimethyl Ether from Synthesis Gas in the Presence of a Megamax 507/γ-Al2O3 Catalyst

Abstract

The kinetics of the direct synthesis of dimethyl ether (DME) from synthesis gas (21.8 vol % CO, 5.2 vol % CO₂, 5.3 vol % N₂, and 67.7 vol % H₂) is studied under laboratory flow reactors in a pressure range of 0.2–5 MPa in the presence of a bifunctional catalyst. The bifunctional catalyst is synthesized by pelletizing a mixture of appropriate fractions of the following milled commercial components: a Megamax 507 methanol catalyst and γ-alumina with a graphite additive. Data on the activation of the bifunctional catalyst are consistent with the TPR data for the original Megamax 507 sample, suggesting that the synthesis conditions for the bifunctional catalyst do not affect the state of copper oxide. At temperatures of up to 280°C, a space velocity of about 4000–10000 L/(kg_cat h), and a pressure of 3–5 MPa, the productivity with respect to oxygenates (DME and methanol) grows linearly along with the load. An increase in load results in a limiting value that can be used to determine the maximum oxygenate productivity of the catalyst as a function of temperature and pressure. A set of experimental data on the effect of space velocity, temperature, and pressure on the composition of the converted gas and the DME/methanol ratio is derived.