The methanol industry overcame many of the obstacles faced by gasoline-methanol blends in the 1970s when it developed MTBE or Methyl Tertiary Butyl Ether. MTBE is a relatively new blending component for the U.S. petroleum refiner.
Because its blending characteristics are close to those of hydrocarbons, MTBE is the only oxygenate generally accepted for blending at the refinery and subsequently transported through pipelines.
The first MTBE plant went on stream in the United States in 1979. EPA permitted a concentration of seven percent by volume in finished unleaded gasoline. Later, the oxygen limit was raised, allowing approximately 15 percent by volume MTBE in unleaded gasoline providing 2.7 percent oxygen by weight.
Current U.S. production capacity of MTBE is over 259,000 barrels per day and is expected to grow to nearly 300,000 barrels per day by the end of the decade. These projections are based on demand for high-octane unleaded gasoline and regulations to reduce vapor pressure. The recent demand for oxygenated fuels for environmental reasons is considered "frosting on the cake" by the petroleum industry and has not been factored into the current demand scenario for projected MTBE growth trends.
Many analysts project MTBE growth at 15 percent per year over the next five year period. There will be a 50 percent increase in the number of MTBE plants in the United States and individual plant capacities will also increase. The increased growth in world production of MTBE will be consumed by countries such as France, Italy and Spain as they begin lead reduction programs in their respective countries.
MTBE was first manufactured commercially in Europe by Chemische Werke Huls in West Germany and ANIC in Italy. Produced by the reaction of isobutylene and methanol, it is one way to use methanol indirectly in motor fuel without the problems associated with adding a light alcohol as a blending component. MTBE was especially attractive to European refiners in the 1970s because of its ability to contribute both low-boiling and high-octane quality to gasoline. This quality is particularly desirable for low-speed performance in the manual transmission vehicles prevalent in Europe. Further, the typical gasolines from the many hydroskimming refineries in Europe were lacking in high-octane olefins in the front end.
Interest in MTBE developedin the United States because of EPA's lead phasedown and the prospect of a future shortage of octane quality in unleaded gasoline. MTBE can be quite attractive for those refiners that have a special economic incentive, e.g., low cost methanol, a petrochemical incentive to separate isobutylene from mixed butylenes, or octane limitations. MTBE also can be attractive as a replacement octane component which, for example, can thus free toluene from its use as a gasoline component and allow it to be used as a petrochemical feedstock.
