Prospects for Direct Natural Gas Conversion to Petrochemical Feedstocks

Natural gas, due to its abundance and low cost, is a major future source as a feedstock for the petroleum and chemical industry. For strategic or economic reasons, it may be undesirable to transport natural gas to potential markets or to use it for transportation fuels. This provides an incentive to investigate various routes to convert natural gas to higher hydrocarbons. Methane, which accounts for over 60% of natural gas, is used today as a source of hydrogen, for ammonia production and to manufacture methanol through steam reforming to the synthesis gas mixtures. However, direct methane conversion to higher hydrocarbon has a high economic incentive as a result of bypassing the synthesis gas step. Recent process development studies have investigated various options for the conversion of natural gas to valuable hydrocarbons. This paper discusses the prospects for direct natural gas conversion by three routes: oxidative coupling to ethylene and higher hydrocarbons, oxidation to methanol or formaldehyde. and oxidation to aromatics by nitrous oxide. Current research activities in the area of natural gas oxidation are reviewed in terms of process conditions, reactor design, catalyst performance in terms of methane conversion and selectivities to various products. Future challenges in reactor and process design for methane oxidation are highlighted.