Direct synthesis of LPG from syngas in a single-tube reactor

A hybrid catalyst for the direct synthesis of liquefied petroleum gas (LPG) from syngas was prepared through mechanical mixing of methanol synthesis catalyst with dehydration catalyst; its catalytic performance was tested in a single-tube reactor with a simulated biogas at 220~330 ℃, 1.2~5.1 MPa and a space velocity of 500~3 000 h^-1. The results indicated that the hybrid catalyst has a good activity; at 325 ℃, 2.1 MPa, and a space velocity of 1 500 h^-1, CO conversion and LPG content in the hydrocarbons product are 72.36% and 71.21%, respectively. At 325 ℃ and 2.1 MPa, a stable operation can be realized at a space velocity below 2 500 h^-1, whereas the temperature cannot be well controlled at a space velocity over 3 000 h^-1, which may lead to the catalyst deactivation. The NH₃-TPD, XRD, N₂ sorption and TPO characterization results suggest that the deposition of coke and decrease of the mount of strong acid sites and surface area are responsible for the catalyst deactivation.