“Green energy” from grain09/06/2006 Bühler and renewable energy: After launching the wood pelleting process and bio-diesel production technology, Bühler’s Grain Milling business unit is now entering another novel business field – bio-ethanol. The process is quite straightforward: Grain is ground. The starch contained in the flour is converted by enzymes into sugar. Through fermentation with yeast, the sugar-containing mash produces up to ten percent alcohol, which is then distilled into high-proof alcohol (spirit or ethanol).
King-size liquor distillery
An ethanol plant is therefore basically simply a huge liquor distillery. Bühler can contribute two essential elements to such a plant. On the one hand, the grain receiving (intake), cleaning, and grinding processes are essentially identical to those of a flour mill. The second element of the Bühler part of an ethanol plant is the processing of the non-fermentable residues obtained from distillation. These so-called “distillers’ dried grains with solubles” (DDGS) contain highly valuable substances. Bühler process technology (pelleting and cooling) allows then to be transformed into a high-protein feed additive. A second option is to use the DDGS as a direct source of energy for the ethanol plant. Here, too, Bühler technology can be applied. For the plant section in which the alcohol process takes place, Bühler is collaborating with companies from the field of biochemistry.
The development of new ethanol plants is in full swing. At present, hammer mills are still frequently being applied to grind the whole grains. But this will also allow substances to enter the fermentation process that cannot be converted to sugar. Dirk-Michael Fleck, bio-ethanol specialist at Bühler: “We can increase the efficiency of a bio-ethanol plant massively by incorporating a fractioning stage in the grinding process.” By applying such a selective grinding process, the components of the grains that do not contain any starch are removed before the actual alcohol process. That conserves energy, and highergrade and safe byproducts are obtained for the animal feed industry. Fleck: “The traditional Bühler grain milling and feed production processes boost the economy of plants for the production of bio-ethanol and bio-diesel. After all, ‘operating reliability’ and ‘energy efficiency’ are customer requirements that Bühler is in an excellent position to satisfy.”
Dirk-Michael Fleck does not doubt for a moment that the market for bio-ethanol stands to continue its sharp growth over the next few years. “The need to reduce carbon dioxide emissions and to gain a certain degree of independence of crude oil is driving the development of ethanol applications,” says the 40-year-old process engineer. “In addition,” says Fleck, “the agricultural industry is systematically seeking new markets in regions with overproduction.” Not least, the use of renewable energy is being subsidized by governments. All these are reasons enough for the industry to increase its investments in ethanol production in anticipation of growing demand. Fleck: “I expect the European ethanol market to multiply over the next five years, in much the same way as in the U.S.”
Corn (maize) and sugar
In the United States and in Brazil, the production of bio-ethanol is a fairly old tradition. In Brazil, several hundred plants are already in operation which produce alcohol from sugar molasses. In the U.S., the production of bioethanol has almost tripled since 2000. By 2006, it is expected that about 20 percent of the entire corn crop of the U.S. will be processed into bioethanol.