Patent Watch

April 28, 2008

Methane feedstock may improve Middle East petrochemical economics. The Middle East’s advantage in petrochemical production economics rests on the availability of low-cost ethane: ~$0.75/million Btu as compared with the United States, for example, where ethane costs ~$6–7/million Btu. This large difference translates into a huge economic advantage for ethylene and key ethylene derivatives, such as polyethylene and ethylene glycol. However, ethane is becoming less available in the Middle East, and new catalytic crackers in the region must now run on ethane–propane mixtures or even naphtha. The Middle East’s advantage diminishes as the feedstock slate becomes heavier; products from Middle Eastern naphtha crackers do not have a great advantage over those elsewhere.

A. Mamedov, T. Joseph, and A. Al-Alwan disclose a catalyst and operating conditions for converting methane into benzene and ethylene. If this process were to reach commercialization, the Middle East’s cost advantage would extend into the ethylene business as well as the aromatics business.

The inventors demonstrated their process in a tubular reactor whose inner wall had been treated with 2 mL Mn(NO₃)₂ catalyst (concentration not specified). A mixture of 70 mol% methane and 30 mol% CO was introduced into the reactor at a temperature of 965 °C. The reactor was non-isothermal, and the outlet temperature was 715 °C. The pressure in the reactor was 2 bar. Methane conversion was 35.8%, benzene selectivity was 32.2 mol%, and benzene yield was 11.53 mol%. On the downside, the selectivity to coke was very high at 43.5 mol%. (Saudi Basic Industries Corp. [Riyadh, Saudi Arabia]. U.S. Patent 7,355,088, April 8, 2008; Jeffrey S. Plotkin)

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