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Driving Without Gas - Chapter 3
Methanol: Practical Considerations and Precautions
If critics of modern technology distrust the speed of its progress, they should find consolation in that it often goes in circles. A century ago, almost all United States steam transportation was powered by a renewable fuel – wood. For more than a decade, there has been talk, research, and action that will inevitably lead to partial return to wood as the raw material of fuel for the automobile. Municipal rubbish, which is very difficult to give away, is rich enough in paper (wood pulp) to be converted into methanol, a motor fuel of first quality.
Methanol (CH3OH) is the international chemical name for wood alcohol, or methylated spirits. It is a widely used solvent and raw material in the chemical and plastics industries. It is the low-priced antifreeze – poisonous, like gasoline, but more often hazardous because it may be confused with ethanol, or "grain" alcohol, and drunk. It is practically odorless. It can be made from coal, wood, waste, or any material containing carbon, but, like many other commodities, it is presently made from the most economical source, natural gas. It should be handled like gasoline, although it is somewhat less hazardous. In an engine it burns cleanly, without depositing carbon. It is the only fuel that a wise yachtsman will use in his galley range, as its exhaust is only water vapor and carbon dioxide, identical with the yachtsman’s own exhalation. If there is a small fire, a pan of water will extinguish it, not spread it, as occurs with a kerosene or gasoline fire.
Up to 15 percent methanol can be added to gasoline in current cars, without adjustment of the engine, and with noticeable improvement in exhaust quality, economy and performance. Methanol has an octane rating of 106, compared to typical gasolines of 85 to 100. It prevents knocking or "pinging" common with unleaded fuels, and it alleviates "running on" or "dieseling" when the ignition is switched off. These practical and well-documented qualities, added to the virtue of reducing national fuel dependence on the Organization of Petroleum Exporting Countries, have made methanol the leading candidate for the motor fuel of the immediate as well as the foreseeable future.
Methanol blends have been tested in many racing automobiles in the past. A series of tests in stock cars was undertaken by T.B. Reed and R.M. Lerner and their colleagues at Massachusetts Institute of Technology. Nine cars, vintages 1966 to 1972, with horsepower from 57 to 335, were tested on blends of 5 to 30 percent methanol. The cars were unmodified and tests were over a fixed course under standard conditions. A summary* of findings was that (1) fuel economy increased by 5 to 13 percent; (2) carbon monoxide emissions decreased by 14 to 72 percent; (3) exhaust temperatures decreased by 1 to 9 percent; (4) acceleration increased up to 7 percent. The elimination of knocking and of "dieseling" was noted, even on the lowest 5 percent methanol blend tested. The latter improvements were unexpected, but were explained tentatively by the possible dissociation of methanol in the car’s cylinder, with attendant absorption of heat energy, quenching early combustion. Simply stated, it burns "cool."
*"Improved performance of Internal Combustion Engines Using 5-20% Methanol." R.M. Lerner et al., Lincoln Laboratory, Massachusetts Institute of Technology.
There are problems in the storage and dispensing of mixtures of methanol and gasoline. Gasoline containing 10 percent methanol will absorb 0.1 percent water – ten times as much as gasoline alone. Thus, in a system using the blend continuously, normal amounts of water formed by condensation are carried away to the engine – the "dri-gas" effect.
However, in wholesale storage and distribution of gasoline, water is sometimes used to displace gasoline to prevent the possibility of vapor accumulation and explosion. Residues of this water, with normal leakage and condensation in tanks, are easily separated by traps in transferring gasoline. But when 10 percent methanol is present, the water will desorb the methanol in large amounts.
At freezing temperatures (0º C.), less than 10 percent methanol is soluble in some gasolines. However, it would appear that changes in the handling of bulk fuel or in the point at which blending occurs would solve the water problems.
Figure 3-1. In properly designed engines, methanol and ethanol produce more brake horsepower (BHP) than gasoline. A gasoline-benzene blend, used in an engine with a compression ratio (C.R.) of 7.7, produced less horsepower than either methanol or ethanol used in an engine with a CR of 9.7 (Source: Donald A. Howes)
The separation of the components may be prevented by the presence of small amounts of higher alcohols in methanol fuels. Curiously, it is easier and thus less expensive to produce methanol with these other alcohols – ethanol, propanol and isobutanol – in it, and the output of a manufacturing plant is increased by 50 percent.
Add Methanol Gradually
A second warning when using a blend for the first time: Add enough methanol to the tank, when taking a trip, to make a 5 percent blend. This will clean out any water in the fuel system. After ten miles, if there is no sputtering, add enough more to make a 10 percent blend.
Drivers wishing to try methanol will be faced with a more difficult problem than cleaning out their fuel system. That is, the problem of finding it in the market. Wholesalers of industrial chemicals and solvents customarily supply it to regular customers in 55-gallon drums as a minimum, or in bulk tank trucks or railroad cars. The supply has always been short, because overproduction would cause storage problems. So unless you know a regular customer "on allocation," who may let you have a few gallons, you will be forced to pay a prohibitive price (for motor fuel) for one-gallon tins sold as shellac thinner, stove fuel, or "spirit solvent."
Large boatyards and marine supply dealers often buy methanol to use as antifreeze in engines in winter storage, or as fuel for yachts’ galley stoves. For the latter, the stuff is decanted into one-gallon tins, for which you will pay from three to six times the price of gasoline. Considering the rising price of petroleum products, an enterprising producer of methanol will no doubt seize the opportunity to expand sales by arranging with a re-tail service station chain, independent of oil company connections, to dispense a premium fuel to motorists.
Critics of methanol blends, often retired engineers writing letters to the newspapers, enjoy pointing out that the alcohols have lower heat contents than gasoline, and therefore must reduce the power and mileage performance. They are correct in the first premise; but because alcohols improve combustion of gasoline and lower the temperature in the cylinders, the blends (up to about 20 percent for methanol) actually improve power and economy. This kind of synergism prevails frequently in the realm of biology, but is seldom perceived or comprehended in mechanics.
Methanol is not highly toxic, but 30 to 100 cc. can be lethal if ingested. It is less dangerous than gasoline if inhaled,* and far less toxic than the two popular household cleaning fluids, trichloroethylene and carbon tetrachloride. If it came into general use, its chief hazards would be controlled by label warnings (not mentioning the word alcohol) and not siphoning fuel by mouth, as is sometimes done in emergencies with gasoline.
*It is not known exactly how much, or at what concentrations, methanol can be inhaled without harm.
Another unsuspected hazard is that of carrying a leaking can in an automobile. Being odorless, the leaking vapor might not be detected in time to avoid considerable inhalation and to avert tragedy.
Advantages of Methanol
There are several advantages to using methanol. A car operated with unleaded gasoline sometimes knocks badly on acceleration. But when a gallon of methanol is added to nine gallons of gasoline in the tank, the knocking disappears. That means increased power, which usually translates into increased mileage. Whether mileage increases 2 percent or 5 percent is not so significant as the 10 percent reduction in petroleum consumption.
Tests with Volkswagens indicate that methanol-gasoline blends lowered exhaust emissions significantly. With 100 percent methanol, gradual additions of water brought reductions in nitrogen oxides and up to 40 percent fewer aldehydes, another potential pollutant.
Some critics complain that there is an increased possibility of vapor-lock. This unpleasant accident occurs in very warm weather with inadequate cooling of a vehicle’s fuel pipe by the air stream. Placed under reduced atmospheric pressure by the suction of the fuel pump, the fuel vaporizes. This slug of vapor in the line blocks the liquid fuel, and the driver is forced to wait until natural cooling and condensation occur or to look for a pan of cold water.
Gasoline refineries already seasonally change the characteristic spectrum of volatile components in their products to reduce the incidence of vapor lock in summer and to facilitate starting in winter. Methanol users have reported no problems of this nature. The problem, for either gasoline or blend users, is one that the manufacturers know how to solve, by fuel pump or piping relocation. They refrain from action for the sake of economy.
One possible complaint against methanol as a blender that arose in the 1930s was that methanol was corrosive to certain materials in a car’s fuel system. At that time, carburetor floats of cork and gaskets sealed with shellac were easy game for alcohol. Present metal floats and synthetic cements resist the solvent action of alcohol. Carburetor parts are made of zinc die castings, sometimes aluminum. The impurities in both metals in earlier days were conducive to "intergranular crystallization" as a result of aging. This crumbing destruction could be accelerated by the presence of alcohol and water, but the problem no longer exists. Lead, tin and magnesium are attacked by methanol, but there should be no opportunity of exposure to these metals in the combustion zones of an engine. Iron and steel are quite immune, as are brass and bronze.
Users of pure methanol found an unsuspected cause of trouble in the gasoline tank, which traditionally has been made of "terne plate," a favorite roofing material of Victorian architects. It is steel sheet coated with lead, making it ideal for resisting rust from water in gas tanks. Methanol reacts with lead, slowly but surely, forming a flaky sludge that plugs filters in fuel pipes. The easiest solution is to inspect and clean the filters every few days when starting to use methanol. The lead will all be gone in a week or two.
The more rational solution will be the decision of manufacturers to abandon terne plate for an epoxy-coated lining in a plain steel tank. The first solution is described in Appendix A. (See Appendix A, the Mx-100 test car.)
100 PERCENT METHANOL FUEL
North American and European ventures into alcohol fuels, both in recent times and in the 1930s, depended on blends ranging from 2 to 95 percent alcohol. The motivations were numerous, but the underlying reason for adhering to blends was that no alteration of the automobile engine was required. However, about 1910, pure alcohol was an established alternative fuel for the horseless carriage. Assuming the availability of methanol at the service station around the corner, what kind of engine would be de-signed for its maximum benefits?
First, the amount of air consumed by burning methanol is reduced. While the ratio for gasoline is 14 weight units of gasoline to 1 of air, for pure methanol it becomes 6 parts fuel to 1 of air. Carburetor jets must be changed.
Second, heat is needed at the methanol intake to vaporize it. A loop of exhaust pipe around the air intake will do the job.
Third, an initial cold start requires an electric glow-plug or a highly volatile primer fluid, such as gasoline or LPG (Liquid Petroleum Gas). Priming fuel is fed to an auxiliary valve from a small tank. Such a conversion might cost around $100, if made on an existing car. If incorporated in a production model, the cost would be one-tenth, or nothing, as the trade-off could be the elimination of emissions control devices.
Methanol burns without misfiring at leaner mixture ratios than gasoline. This does not mean that it uses less fuel – in fact, methanol quantity consumed will double – but it indicates more complete combustion and less pollutant exhaust than gasoline. Temperature of exhaust is 100 degrees centigrade lower than with gasoline, and spark timing can be later (more efficient) with methanol because of its higher flame speed. Higher compression ratios are feasible without toxic additives, and "dieseling," or running on after the ignition switch is turned off, is eliminated because of the higher heat of methanol evaporation. (Methanol is not a good diesel fuel.)
For the ordinary driver, these qualities will be apparent in improved acceleration, a lighter car and engine, fewer parts to service (no catalytic converter, etc.), but a car that needs about twice the fuel-tank size for the same mileage as gasoline. This problem caused the sad failure of the Novis, an advanced design of Indianapolis "500" race entries, designed to run on 100 percent methanol but unable to finish the race at the speeds of their qualifying runs. The rules limited the fuel used – in gallons instead of in heat units.
To Be Continued....
Copyright 1980 by Garden Way, Inc.
This material provided under "Fair Use" guidelines.
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