Corn Starch and Corn Gluten

For obtaining starch from corn, the important thing is to release the starch from the cell structure in particular, without damaging the germ and thus to obtain extracted corn starch with the minimum possible fat content. For this reason, conventional processes subject the corn to a 30 to 50-hour steeping process with the addition of sulfur dioxide before processing to make the corn grain amorphous in structure and achieve efficient separation of starch and gluten. In primary separation, this separation is effected by a highly efficient nozzle separator. After the starch phase has been washed with the aid of hydrocyclones, it is dewatered and dried or passed to a saccharification unit.

Following concentration of the thin gluten, the corn gluten is concentrated by a nozzle separator before being dewatered in a DiscDecanter and then dried. The DiscDecanter combines the functions of decanter and separator in one machine and thus represents an innovation associated with far-reaching benefits for the starch manufacturer: in the dewatering of corn gluten, the finest particles which a decanter, as a solids-oriented machine, cannot pick up used to be separated in a downstream stage. This is now no longer required. The DiscDecanter has a special disk stack with which all the relevant extremely fine particles can be effectively separated. These extremely fine particles are conveyed back into the solids chamber of the decanter and discharged with the solids. With under 2 g solids per liter, the clear phase achieves process water quality, a value which cannot be achieved with the kind of vacuum filter conventionally used.

An additional benefit results from the consistency of the separated gluten solid. Whilst a vacuum filter produces a highly compressed product, the DiscDecanter produces a dry, crumbly solid which is much easier to dry. The drying stage can accordingly have smaller dimensions.