Due to the ban of MTBE in California Petrobras decided to adapt its MTBE units to produce isooctane and / or isooctene, a valueable gasoline component.

As Petrobras has 4 MTBE units and as Brazilian legislation doesn't allow the addition of MTBE into gasoline, the production of MTBE in Petrobras is mostly exported to the USA.

This paper shows the dimerization and hydrogenation technologies developed in-house from bench scale to industrial runs in order to make it feasible to produce isooctane that will be added to Petrobras' special gasolines or exported if desired.


Since the end of the 70's MTBE has been used as an additive in the gasoline pool. Due to the approval of the Clean Air Act Amendment in the U.S. in 1990 which defined an addition of oxygenates to reformulated gasoline in order to achieve a minimum of 2 % oxygen by weight the use of MTBE in the gasoline pool had further increased.

In the beginning of the 90's, Petrobras decided to build and operate 7 MTBE plants basically aiming the external market, mainly U.S.. So, in 1996 Petrobras started up three MTBE plants and in 1997 another one that summed up a total capacity of 300,000 t / year. Others 3 units were in the basic engineering phase.

In 1995 the Brazilian Congress set a legislation, as an incentive to alcohol industry, defining that only ethanol could be added to the Brazilian gasoline pool as an oxygenate, what made exporting MTBE a must to Petrobras. Not only for this resolution but also due to logistic difficulties, the project of the other 3 units was discarded.

Unfortunately, due to MTBE solubility in water and spills from underground gasoline storage tanks and domestic boats a large number of contaminations occurred in drinking water systems and lakes in USA.Although the adverse health effect of MTBE was not definitive proved it had been proposed and approved in the U.S. legislation the ban of MTBE in several states. In California the biggest MTBE U.S. market the deadline for the phase-out has already happened at January 1st, 2004. Others American states followed the same attitude.

The loss of MTBE has consequences in octane, volatility, emissions and volume of the gasoline pool. Many refiners and process engineering companies that are players in the U.S. market are analysing alternatives to replace MTBE and also taking decisions about what will be done with the MTBE plants.

Because the lack of demand, the MTBE price in the international market is going down, generating lower profit of keeping the units operating.

Based on this, Petrobras as several other refiners and petroleum companies is evaluating alternatives to their MTBE plants such as:

  • shut-down the plants, using the main equipments to other units or revamps;

  • adapt to ETBE production;

  • revamp to isooctene and isooctane production.

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