Methanol Fuel

This article is about Methanol used as a fuel. For other alcohols used as fuels, see Alcohol fuel.

Methanol has been proposed as a fuel for internal combustion and other engines, mainly in combination with gasoline. Methanol fuel has received less attention than ethanol fuel as an alternative to hydrocarbon fuel. However, in 2005 Nobel prize winner George A. Olah advocated an entire methanol economy based on energy storage in synthetically produced methanol, in an essay and in 2006 he and two co-authors published a book around this theme.

Methanol is used on a limited basis to fuel internal combustion engines, mainly by virtue of the fact that it is not nearly as flammable as gasoline. Pure methanol is required by rule to be used in Champcars, USAC sprint cars (as well as midgets, modifieds, etc.), and other dirt track series such as World of Outlaws. Methanol is also used in radio control, control line and free flight airplanes (required in the "glow-plug" engines that primarily power them), cars and trucks. Drag racers and mud racers also use methanol as their primary fuel source. Methanol is required with a supercharged engine in a Top Alcohol Dragster and, until the end of the 2006 season, all vehicles in the Indianapolis 500 had to run methanol. Mud racers have mixed methanol with gasoline and nitrous oxide to produce more power than gasoline and nitrous oxide alone.

One of the drawbacks of methanol as a fuel is its corrosivity to some metals, including aluminium. Methanol, although a weak acid, attacks the oxide coating that normally protects the aluminium from corrosion:

The resulting methoxide salts are soluble in methanol, resulting in clean aluminum surface, which is readily oxidised by some dissolved oxygen. Also the methanol can act as an oxidizer:

This reciprocal process effectively fuels corrosion until either the metal is eaten away or the concentration of CH₃OH is negligible.

When produced from wood or other organic materials, the resulting organic methanol (bioalcohol) has been suggested as renewable alternative to petroleum-based hydrocarbons. However, one cannot use pure methanol in modern petroleum cars without modification, due to potential damage to metal piping and rubber seals.

History and production

Historically, methanol was first produced from pyrolysis of wood, resulting in its common English name of wood alcohol. Presently, methanol is usually produced using methane (the chief constituent of natural gas) as a raw material. It may also be produced by pyrolysis of many organic materials or by Fischer Tropsch from synthetic gas. Production of methanol from synthesis gas using Biomass-To-Liquid can offer methanol production from biomass at efficiencies up to 75%. Widespread production by this route has a postulated potential (see Olah reference above) to offer methanol fuel at a low cost and with benefits to the environment. These production methods, however, are not suitable for small scale production.

Use as internal combustion engine fuel

Both methanol and ethanol burn at lower temperatures than gasoline, and both are less volatile, making engine starting in cold weather difficult. Using methanol as a fuel in spark ignition engines can offer an increased thermal efficiency and increased power output (as compared to gasoline) due to its high octane rating (114^[1]) and high heat of vaporisation. However, its low energy content of 19.7 MJ/kg and stoichiometric air fuel ratio of 6.42:1 mean that fuel consumption (on volume or mass basis) will be higher than hydrocarbon fuels. The extra water produced also makes the charge rather wet and combined with the formation of acidic products during combustion, the wearing of valves, valveseats and cylinder can be higher than with hydrocarbon burning. Certain additives may be added to motor oil in order to neutralize these acids.

Methanol, just like ethanol, contains soluble and insoluble contaminents ^[2]. These soluble contaminants, halide ions such as cloride ions, has a large effect on the corrositivity of alcohol fuels. Halide ions increase corrosion in two ways; they chemically attack passivating oxide films on several metals causing piting corrosion, and they increase the conductivity of the fuel. Increased electrical conductivity promotes electrical, galvanic and ordinary corrosion in the fuel system. Soluble contaminents such as aluminumhydroxide, itself a product of corrosion by halide ions, clogs the fuel system over time.

Methanol is hygroscopic, meaning it will absorb water vapor directly from the atmosphere.[1] Because absorbed water dilutes the fuel value of the methanol (although, it supress engine knock), and may cause phase separation of methanol-gasoline blends, containers of methanol fuels must be kept tightly sealed, and cannot be stored for long periods once opened.

Toxicity

Methanol is extremely poisonous; less than a cup can cause permanent blindness or death, and it doesn't have to be swallowed to be dangerous since the liquid can be absorbed through the skin, and the vapors through the lungs. US maximum allowed exposure in air (40 h/week) are 1900 mg/m³ for ethanol, 900 mg/m³ for gasoline, and 260 mg/m³ for methanol. It is however less volatile than gasoline and this decreases evaporative emissions. In the liver, methanol is metabolised into two potent toxins: formaldehyde (used as a preservative for dead organic matter in laboratories), and formic acid (the poison found in ant stings). Use of methanol, like ethanol, significantly reduces the emissions of certain hydrocarbon-related toxins such as benzene and 1,3 butadiene.

Safety

Since methanol vapour is heavier than air, it will linger close to the ground or in a pit unless there is good ventilation, and if the concentration of methanol is above 6.7% in air it can be lit by a spark, and will explode above 54 F / 12 C. Once ablaze, the flames give out very little light making it very hard to see the fire or even estimate its size, especially in bright daylight. If you are unlucky enough to be exposed to the poisonous substance through your breathing system, its pungent odor should give you some warning of its presence. However, it is difficult to smell methanol in the air at less than 2,000 ppm (0.2%).

Use in racing

Beginning in 1965, pure methanol was used in United States Auto Club competition for its series, which then included the Indianapolis 500.

A seven-car crash on the second lap of the 1964 Indianapolis 500 resulted in USAC's decision to mandate methanol. Eddie Sachs and Dave MacDonald died in the crash when their gasoline-fueled cars exploded. The gasoline-triggered fire created a dangerous cloud of thick black smoke, which completely blocked the view of the track for oncoming cars. Johnny Rutherford, one of the other drivers involved, drove a methanol-fueled car which also leaked following the crash. While this car burned from the impact of the first fireball, it formed a much lesser inferno than the gasoline cars, and one that burned invisibly. That testimony, and pressure from Indianapolis Star writer George Moore, led to the switch to alcohol fuel in 1965.

Methanol is currently used by the Champ Car circuit and many short track organizations, especially midget, sprint cars and speedway bikes. Pure methanol was used by the IRL until the 2006 season.

In 2006, in partnership with the ethanol industry, the IRL used a mixture of 10% ethanol and 90% methanol as its fuel. For the 2007 season , the IRL will use pure ethanol, E100. ^[3]

Methanol fuel is also used extensively in drag racing, primarily in the Top Alcohol category.

Formula One racing continues to use gasoline as its fuel, but in pre war grand prix racing methanol was often used in the fuel.

Methanol fuel programs in the U.S. and other nations

The State of California ran an experimental program from 1980 to 1990 which allowed anyone to convert a gasoline vehicle to 85% methanol with 15% additives of choice. Over 500 vehicles were converted to high compression and dedicated use of the 85/15 methanol and ethanol, with great results. Detroit was not willing to produce any methanol or ethanol vehicles without government subsidy.

In 1982 the big three were each given $5,000,000 for design and contracts for 5,000 vehicles to be bought by the State. That was the beginning of the low compression "FLEX-FUEL" vehicles which we can still buy today.

In 2005, California's Governor, Arnold Schwarzenegger, terminated the use of methanol after 25 years and 200,000,000 miles of success, to join the expanding use of ethanol driven by producers of corn. In spite of this, he was optimistic about the future of the program, claiming "it will be back." Ethanol is currently (as of 2007) priced at 3 to 4 dollars per gallon, while methanol made from natural gas remains at 1 dollar per gallon.

A drive to add a significant percentage of methanol to gasoline got very close to implementation in Brazil, following a pilot test set up by a group of scientists involving blending gasoline with methanol between 1989 and 1992. The larger-scale pilot experiment that was to be conducted in São Paulo was vetoed at the last minute by the city's mayor, out of concern for the health of gas station workers (who are mostly illiterate and could not be expected to follow safety precautions). As of 2006, the idea has not resurfaced.

Contents

History and production

Use as internal combustion engine fuel

Toxicity

Safety

Use in racing

Methanol fuel programs in the U.S. and other nations

See also

References

External links