Cross-flow filtering process for separating fluid from a free-flowing medium and installation for implementing it
AssigneeBucher-Guyer AG
InventorEduard Hartmann
Life of this patent
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Abstract
For thickening a retentate by means of membrane filtration (ultra-/micro-filtration) to obtain the highest possible wet sludge proportion, a gaseous medium is admixed with the retentate. To this end an open feed line (13) above the retentate level (14), a porous ring (17) in the retentate, or a simple line connection (19, 20, 28, 29) in a tank (6) are proposed. A number of advantages accrue as a result of the lowering of the viscosity of the retentate achieved in this way, such as savings of energy for retentate recirculation, efficient installations because of longer series or passes of filtration modules, and savings in squeezing installations because of the direct filtration with high solid components.
Claims13
A cross-flow filtration method for thickening a solid-liquid mixture, comprising moving the mixture to be filtered in the form of retentate through at least one membrane module (1, 41) with porous membranes (2) to separate liquid filtrate therefrom through said membrane, and reducing the viscosity of said retentate to facilitate the movement thereof through said at least one membrane module by admixing a gaseous medium with the retentate, said gaseous medium being only admixed with the retentate if the viscosity of the retentate lies above a preset value.
An installation for thickening a solid-liquid mixture to a high solids content, comprising at least one filtration module (1, 41) with porous membranes (2), over which a stream of the solid-liquid mixture to be filtered can be passed tangentially as the retentate by a conveying pump (8) and a feed line (3) to the filtration modules (1, 41), and a device (13, 17, 19, 20) for reducing the viscosity of said retentate to facilitate the movement thereof through said at least one filtration module by admixing a gaseous medium with the solid-liquid mixture to be filtered, wherein said device for admixing (20) comprises a gas supply line, in which a regulating element (21) for the amount of gas supplied is arranged, and wherein said regulating element (21) for the amount of the supplied gas is operatively connected with a device for measuring viscosity (25), pressure (26, 27) or flow-through (9) of the retentate.
Dependencies are inferred from the claim text.