**5. Utilization of alcohol fuels**

About 66% of worldwide ethanol products are used for transportation purpose and 21% goes to industrial use. Most widely used area is gasohol in that alcohols are mixed to replace a portion of gasoline. In the near future, alcohol-using fuel cells and alcohol-mixed jet fuels are promising area of application.

**Figure 9** shows the ethanol consumption trend for mixing to gasoline in the United States during the period of 1980–2020. During the years 2005–2010, ethanol use has drastically increased and remains as ca. 10% of the total gasoline consumed amount.

#### **5.1 Fuel for automobiles**

The most abundant application of alcohol fuels is related to internal combustion engine of automobiles. Mixing alcohol fuels into gasoline has also a purpose of reducing pollutants by oxygenating the fuel. Since methanol is less expensive

#### **Figure 9.**

*Trend of alcohol additive consumption for gasoline in the United States [18].*


#### **Table 6.**

*Ethanol mixing program to gasoline in different countries [11].*

to produce than ethanol, although methanol is generally more toxic and has lower energy density than ethanol, it has been used with ethanol as automobile fuels. Compared to gasoline, methanol and ethanol have characteristics of burning at lower temperatures and lower volatility, which results in difficulty in starting the automobile engine in cold weather.

Current alcohol mixing status of ethanol-based fuel utilization in different countries is tabulated in **Table 6**.

Currently, flexible fuel vehicle (FFV) with dual fuel supply system for ethanol and gasoline is commercialized and widely distributed. In the case of methanol blending to gasoline, it is limitedly used in China from the 2000s. In China, M15 (15% methanol/85% gasoline) is the most familiar type [19].

Low-molecular weight alcohols such as ethanol have replaced conventional octane boosting additives like MTBE in automobile fuels. Alcohols that are added to gasoline make the mixed fuel to combust more completely by acting of higher oxygen content by alcohols and provide the ensuing effects of higher combustion efficiency and lower air pollution emissions [20].

In the United States, bio-ethanol is mandatorily mixed with transportation fuels. It has been reported that the bio-ethanol policy reduced crude oil reliance to 25%

### *Alcohol Fuels: Current Status and Future Direction DOI: http://dx.doi.org/10.5772/intechopen.89788*

from 60%, and simultaneously creating 400,000 jobs, reducing 43% in greenhouse gas generation and cost-saving effect of \$1.5/gallon-gasoline to the consumer [13].

Small amounts of methanol and higher alcohols are also allowed to be blended into gasoline within EN228 limits. E85 is used in FFVs in certain areas within the EU (such as Sweden, France, and Germany) [21]. There was a trial to use a near-neat fuel as M85 which contains 85% methanol/15% gasoline.

Racing cars used methanol for a long time, mainly by not producing black smoke which otherwise will block the view of ensuing other racing cars. Other than this application to racing cars, methanol fuel has not applied widespread other than some experience in China, methanol programs in California during the 1980–1990s, and a trial in Sweden as a marine fuel.

More than 98% of US gasoline contains typically 10% ethanol as E10 (10% ethanol/90% gasoline) [7]. Flexible fuel automobiles that can use E85 (85% ethanol/15% gasoline) exist in the United States and Brazil.

In Brazil, 95% of automobiles are using fuel-flex engine system. Around 70% of automobiles in Brazil are able to run on ethanol, and the Brazil's demand for ethanol is estimated to increase by around 70% by 2030 (**Figure 10**) [1, 22].

As for bio-butanol, the commercial scale production facility has not been constructed in sufficient numbers. In the United States, bio-butanol can be mixed up to 12.5%, and the 16% mixture is reported to be equivalently effective to existing E10 [13].

Ethers such as dimethyl ether (DME) contain oxygen in chemical structure which acts as an oxidant in minimizing soot formation. Other exhaust emissions such as unburned hydrocarbons, NOx, and particulate matter are also reduced [8]. DME is an ultra-clean fuel that has similar properties to LPG.
