Abstract: In the production of ethanol in plants, comprising a fermenter, a centrifugal separator for the recirculation of the yeast to the fermenter and a plant for the separation of a yeast-free flow, coming from the centrifugal separator, into one flow, rich in ethanol, and into one residual flow, the substrate, that is fed to the fermenter must be rid of solid substance, like fibres etc. In the separation of such solid substance a certain amount of substrate has been lost according to the methods utilized hitherto, or an unnecessarily high consumption of water and energy has occurred. According to the invention the solid substance, which is separated from the raw material flow, is washed, preferably countercurrently with said residual flow, which in turn, enriched in substrate, is fed to the fermenter. If a distillative method is used for said separation the residual flow is called slop.

Abstract: Each group of conical cyclone separators is arranged in an annular block with their longitudinal axes in a common plane, each side of each block having concentric sealing surfaces coacting with corresponding sealing surfaces of an adjacent similar block to seal against leakage from an inlet opening for supplying the separators. Preferably, the stack of blocks surrounds a central shaft for clamping the blocks together and forming a discharge path for the heavier constituent from the separators, the lighter constituent discharging from the separators at the outer periphery of the stack into a chamber surrounding the stack.

Abstract: The water phase from a corn steeping step is evaporated in a multistage evaporator to a steeping concentrate, the steeped corn being divided into an aqueous germ fraction, an aqueous fiber fraction and a gluten suspension which is partly dewatered to an aqueous gluten fraction. Said three fractions are dried to a low water content by heating while subjected to a direct air flow, causing steam-air flows from said fractions. In the drying of said fractions, the air flow is limited to make the enthalpy of the steam-air flows relatively high, and part of the steam-air flows, preferably combined, is fed to one stage of the evaporator, preferably the first stage to which the water phase from the steeping step is fed.