Fuel ethanol production is directly linked to the production of sugar. In fact, gen­erally speaking, ethanol can be considered as a co-product in the sugar industry, but it also can be the main end product obtained from sugarcane. In the for­mer case, cane molasses formed during sugar processing is employed for ethanol production. However, the requirements of fuel ethanol in cane sugar-producing countries with gasoline oxygenation programs cannot be covered with the sole molasses. Therefore, autonomous (stand-alone) distilleries not co-located near sugar mills have been put into operation in countries like Brazil in order to meet the required amounts of fuel ethanol. These distilleries use the sugarcane to produce ethanol exclusively. Besides molasses, some sugar mills use the cane juice for producing ethanol in their co-located distilleries. This means a reduced amount of produced sugar compared to when the mill does not produce ethanol. This is the case in Colombia whose sugar production has been decreased due to the implementation of the gasoline oxygenation program using E10 blends. The rise in the domestic price of sugar during 2006 through 2008 has been explained not only by the increase in the international oil price, but also by the onset of this program (Sanchez and Cardona, 2008a).

The technology for fuel ethanol production from sugar-rich materials (mostly sucrose) offers multiple alternatives regarding the use of feedstocks generated within the sugar mills. For instance, and excluding the cane juice and molasses, Colombian distilleries use part of the clarified syrup. In this way, a great flexibil­ity for production of both sugar and ethanol is attained, exploiting the integration of the different sugar-rich streams during sugar processing. For sugar mills, this flexibility allows them to respond in a suitable way to the changes and needs of both ethanol and sugar markets.

In the case of ethanol production facilities using sugar beet, both the diffusion juice and beet molasses can be employed for producing bioethanol. The produc­tion of fuel ethanol directly from the beet juice is a nonviable technological option for most countries producing sugar from sugar beet due to the higher costs of the juice produced and to the need of covering their domestic sugar demands as in the case of European countries and North America. For these countries, ethanol is mostly produced from corn, wheat, and other grains. In fact and according to Decloux et al. (2002), there exist no stand-alone distilleries producing ethanol from beet juice in France, the first ethanol producer from sugar beet. Instead of that, the distilleries are co-located next to sugar mills. Some important issues concerning the main sucrose-containing feedstocks for ethanol production are highlighted below.

TABLE 3.5

Composition of the Raw Sugarcane Juice