Bma Braunschweigische Maschinenbauanstalt Ag

Jens Mahrholz

Dirk Spangenberg

Andreas Lehnberger

Uwe Schwanke

A method for controlling the operation of a continuously or periodically operating centrifuge can be employed in the sugar industry for separating crystalline carbohydrates or sugar alcohols from a crystal suspension called a magma or a mother liquor. The magma has a varying content of fine grain that is dependent on the properties of the pretreatment and of the raw material. Variable control values are provided in a control device of the centrifuge. One or plurality of sensors are provided that carry out the measurements in electromagnetic, optical, acoustic, and/or conductive ways. These measurements that are conducted serve for determining the fine grain fraction of the magma. The measurements are supplied as measurement signals to the control device of the centrifuge. The control device automatically analyzes the measurement signals supplied to it and evaluates them with respect to the fine grain content of the magma. The control device changes the variable control values of the centrifuge as a function of this evaluation.

Method for controlling the operation of a continuously or periodically operating centrifuge and device for conducting the method

A method for obtaining crystals from a mother solution operates such that mother solution is fed into a crystallisation device. Supersaturation of the mother solution is brought about by open and/or closed-loop control of the temperature (&#x25a1;). Seed crystals are added to the mother solution at a seeding point (Sp). The seed crystals are grown as nuclei by continuous closed-loop process control and are finally removed from the method as crystals. They form the product yield. The formation of crystal nuclei in the mother solution is countered by steps in the closed-loop process control. During the closed-loop process control and the crystallisation procedure, the position of the limit (M) of the formation of secondary nuclei is determined using sensors that detect data currently, wherein the position of the limit (M) is established as a value of the concentration (c) and the temperature (&#x25a1;) from these data. This determined position of the limit (M) of the formation of crystal nuclei is used as the basis for the closed-loop process control of the crystallisation.

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Braunschweig, Germany

Jens Mahrholz