Synthesis of liquefied petroleum gas via methanol/dimethyl ether from natural gas

Synthesis of liquefied petroleum gas (LPG) via methanol/dimethyl ether (DME) from natural gas was studied. Acidic zeolite-based catalysts with small-, medium- or large-pore sizes were tested for selectively converting methanol/DME to LPG fraction, C-3 and C-4 hydrocarbons. Medium-pore zeolite ZSM-5 with around 50 of silica to alumina was clarified to be one of the potential catalysts for that conversion. Reaction conditions, liquid space time, temperature and co-feeds, were also examined by using the ZSM-5 catalyst. Dimethyl ether can also be converted to LPG fractions on the catalyst. The co-feed of methanol and ethylene reacts to form the enriched C3 and C4 hydrocarbons. These results are suggested that the ethylene-rich C-2 hydrocarbon recycle makes the process selectivity of LPG increase. Hydrogenation tests for the unsaturated hydrocarbons were carried out on a commercial 0.3 wt.% Pt/C catalyst. Hydrocarbon saturation has proceeded until nearly 100%. Summarizing the results, a total process flow scheme was proposed for synthesizing high-quality liquefied petroleum gas via methanol/dimethyl ether from natural gas. (C) 2004 Elsevier B.V. All rights reserved.