CEH Report

Table of Contents

Abstract

This report focuses on blending agents incorporated into gasoline mainly to raise the octane value of the fuel and to reduce harmful vehicle emissions. Gasoline with an octane rating that satisfies market requirements is produced in refineries by blending various refinery streams that differ in composition, boiling range and octane rating.

Gasoline octane improvers/oxygenates include three major compounds—ethanol, methyl tertiary-butyl ether (MTBE) and ethyl tertiary-butyl ether (ETBE).

The following pie charts show world consumption of fuel ethanol and MTBE in gasoline:

The largest-volume gasoline octane improver/oxygenate used in the world in 2008 was ethanol. In recent years, ethanol use has grown significantly in the United States and Brazil, and to a lesser extent in Western Europe, for several reasons:

• It boosts octane levels.
• It increases combustion efficiency, as ethanol is an oxygenate that helps reduce air pollutants.
• Ethanol made by fermentation is a renewable resource.
• It is biodegradable in surface water, groundwater and soil.
• It extends gasoline supplies.
• It decreases emissions of greenhouse gases (GHGs), although the extent of reduction depends on the feedstock and other factors.
• It supports local agriculture. In the industrialized world, agriculture often has a strong political influence on national policies, so increased ethanol production in the United States is supported strongly by Midwestern corn growers. In the less industrialized world, stimulation of local agriculture is very attractive to government officials.
• It decreases dependency on imports of crude oil or gasoline if the country is not a producer of crude oil but is a producer of ethanol.

The next-leading gasoline octane improver/oxygenate is MTBE. Starting in the late 1970s, MTBE was the predominant choice of gasoline oxygenate used worldwide because of its low cost, high octane value and easy incorporation into gasoline stock. However, in the late 1990s, MTBE was alleged to cause detrimental environmental impacts by contaminating water supplies. As a result, use in Japan ceased in 2003, and in the United States and Canada in 2006. Global use peaked in 2000 at about 20.4 million metric tons.

The United States still produces MTBE but practically all is exported. However, output will decline significantly as the largest producer, LyondellBasell, shuts down one of its units and converts 30% of its remaining capacity to ETBE during 2009. There are several large Latin American consumers of MTBE; the largest are Mexico and Venezuela. Both countries import considerable quantities of MTBE from the United States; both have made some plans to use more ethanol or ETBE to reduce GHGs, but general inertia and fear of higher corn prices will limit the switch. In Brazil, there is no consumption of MTBE, and all of the production is exported.

Global consumption of ETBE in 2008 was almost all in Western Europe, with a lesser amount in Eastern Europe. Western Europe partially switched from MTBE to ETBE, mainly as a result of tax incentives for refiners and blenders to use ethanol to make fuels from renewable resources. There are almost twenty ETBE plant sites in the EU 25, with production dominated by Total and its subsidiaries and joint ventures, LyondellBasell and Repsol-Petróleo. Some MTBE producers can switch between MTBE and ETBE.