Ethanol is produced from a variety of feedstocks. Fermentative ethanol is produced from grains, molasses, sugarcane juice, fruits, surplus wine, [8]

whey, and some other similar sources, which contain simple sugars and their polymers. On the other hand, synthetic ethanol is produced from oil, e. g., through hydration of ethylene:

Oil ^ CH2 = CH2 (ethylene) —CH3CH2OH (ethanol) (3.1)

Several companies, such as Sasol, SADAF, British Petroleum, and Equistar, produce synthetic ethanol, with capacities of 100-400 kilotons/yr. However, the share of synthetic ethanol in world ethanol production was less than 4% in 2006, down from 7% in the 1990s [4]. Furthermore, increasing oil price or declining ethanol price can harm the economic competition of synthetic ethanol production, compared to the fermen­tative one. Ethylene prices in 2005 rose to US $1000 per ton, while ethanol values were around US $500 per ton. If we consider the theo­retical yield of ethanol from ethylene based on Eq. (3.1) as 1.64 kg/kg, the price of raw materials was higher than that of the product. In this case, it is economically feasible to produce biobased plastics through “bioethylene”:

Fermentation H2O

Biomass/crops————— ► CH3CH2OH—- > CH2 = CH2 ^ Plastics (3.2)

The global demand for ethylene is around 120 megatons [4]. It can be considered a new market for ethanol in the future.

The total world ethanol production in 2006 was 49.8 GL (gigaliter) (39 megatons), where 77% of this production was used as fuel, 8% as beverage, and 15% in industrial applications [4]. Since 1975, potable ethanol production has not experienced a major growth, while industrial ethanol production has experienced growth by about 75%. However, fuel ethanol production has increased aggressively from less than 1 GL in 1975 to more than 38 GL in 2006 (see Fig. 3.1).

There is competition between Brazil and the United States to be the dominant ethanol producer in the world. So far, Brazil has been the largest ethanol producer, but the statistics from 2006 imply that the United States is the largest ethanol producer with 19.1 GL, followed by Brazil with 16.7 GL. Both countries produced almost identical amounts of ethanol in 2005 (16.2 and 16.0 GL, respectively). The American conti­nents produced 72% of the world ethanol production (see Fig. 3.2), fol­lowed by Asia, Europe, Oceania, and the African continents.

There is tough competition between sugar crops (particularly sugar­cane juice and molasses) and starch crops (particularly maize) as feed­stock for fuel ethanol production. While sugar crops were the feedstock for more than 60% of fuel ethanol production at the beginning of the 2000s, its share decreased to 47% in 2006 and starch crops were used for 53% of fuel ethanol production in the same year.

The world fuel ethanol production is predicted to keep the latest trend, at least until 2015. In comparison to 2006, ethanol production by Brazil and the United States is expected to increase by 102% and 93%, respectively. However, total production of the rest of the world is expected to increase by 585% [4]. Therefore, the world fuel ethanol pro­duction is expected to increase to around 100 GL. The main reasons for this sharp increase in ethanol production and demand in the future might be [2, 5, 6]:

■ Possible increase in oil prices

■ Higher demand for liquid fuels in the future

■ Decline of the crude oil supply in the future

■ Environmental legislation in different countries to encourage using biofuels

■

Production of bioplastic materials from ethanol