The market for gasohol is still very small and its production costly, but this promising alternative to gasoline has a higher octane than the real thing and cuts down on the consumption of oil.
Conservationists are particularly excited about gasohol, for in the final analysis, it is solar energy that drives your car through the organic raw materials of gasohol, such as corn or sugarcane.
Gasohol is a blend of 10 percent ethyl alcohol (ethanol) and 90 percent unleaded gasoline. Ethanol is produced by fermentation of starches and sugars. By far the largest source for this is corn, which is the most abundant of cereal grains grown in the United States. Oats, barley, wheat, and milo can be used, as well as sugarcane, sweet sorghum, and sugar beets. Potatoes and cassava (a starchy plant) are possible sources, as is cellulose, which can be broken down into fermentable sugars.
Just about any fuel can be used to power the fermentation plant in which ethanol is made: coal, agricultural and industrial wastes, natural gas, solar or geothermal energy, and oil.
The corn is ground and cooked so that the starch can be processed further. Enzymes are added to convert the starch to sugars, which in turn are converted to alcohol by reacting with yeast. The alcohol is distilled until it is 190 proof, that is, 95 percent of the substance is alcohol. Finally, any vestiges of water are removed so that the alcohol is totally dry 200 proof. This ethyl alcohol is then blended with unleaded gasoline.
The yield of ethyl alcohol from one acre of produce varies. An acre of corn yields 250 gallons; an acre of sugar beets, 350 gallons; an acre of sugarcane, 630 gallons. Producers of gasohol are anxious that land be set aside solely for growing crops for production of ethanol, but the depletion of food supplies, nutrients, and organic soil constituents remains a matter of concern.
Since alcohol is an excellent solvent, it is essential that all equipment handling gasohol be clean. Mechanical problems have resulted from clogged filters, especially in old cars, in which gasohol loosens accumulated dirt. Oil companies report that mileage improvement is questionable, but, in general, engines that run on gasohol tend to foul less and to run cooler and cleaner. And, of course, in a time of dwindling oil imports and limited supplies, the fact that gasohol contains less oil than gasoline is certainly appealing.
In the future it may become economical to produce gasohol from garbage. The cellulosic portion, paper and wood, of municipal waste, although readily available, must be subjected to radical treatments before the yeasts can act upon it.
First, the lignin, which forms a hard shell around the cellulose, must be cracked, either in pressure cookers or by explosion from high pressure jets into low pressure areas, which causes the lignin to swell. Then the cellulose cells, containing thousands of units, must be broken down into single or double sugars by addition of water and treatment either by sulfuric acid, this method is rapid but costly, or by enzyme action, which requires two days.
When these processes are made less cumbersome and expensive, however, we may be running our cars on old newspapers.