ASTM publishes D7862 standard for butanol

By Susanne Retka Schill | October 03, 2013

Butanol has a new ASTM International standard, intended for blends with gasoline at 1 to 12.5 percent volumes to be used as an automotive spark-ignition engine fuel. ASTM D7862 establishes performance requirements and test methods for butanol content, water content, acidity, inorganic chloride, solvent-washed gum, sulfur content and total sulfate.

“The new ASTM standard for butanol will further commercialization of a new renewable fuel, and provide a fuel quality standard to govern the production and marketing of butanol,” says Glenn Johnston, executive vice president, regulatory affairs, Gevo Inc., and a member of the ASTM Do2 subcommittee on gasoline and oxygenated fuels. “It’s another alcohol that can be used and broaden the base. It should help get more people interesting in investing in the space,” he said, adding it should help biofuels of all types.

Johnston says that butanol has several benefits as a blending agent in gasoline. Butanol is compatible with existing vehicles and refueling infrastructure, and it also offers a high blending value due to its low vapor pressure, high octane number and favorable distillation properties.

The new specification covers three butanol isomers: 1-butanol (commonly known as N-butanol which is being developed by Cobalt), 2-methyl-1-propanol (commonly known as isobutanol, being developed by Gevo and Butamax) and 2-butanol. The standard specifically excludes 2-methyl-2-propanol (tert-butyl alcohol), which has different physical properties.

Butanol contains 22 mass percent of oxygen. The mass percent of oxygen in butanol blends with gasoline will depend not only upon the volume of butanol but also the density of the butanol isomer used and the density of the base blendstock. ASTM D7862 provides a test method for determining the percentages.

The ASTM D7862 specification will be used by biofuel producers, petroleum refiners, gasoline blenders, government agencies, inspection laboratories, and manufacturers of motor vehicles, marine engines and outdoor power equipment.

Johnston, who led the task force involving 86 industry representatives, encourages all interested parties to join in the standards developing activities of D02.A0. The subcommittee next plans to develop a proposed standard on the use of butanol in flexible fuel vehicles.

More information on the new standard can be found here.