Voest-alpine Aktiengesellschaft

Franz W Mayer

Alois Janusch

Gero Tessmer

A drying plant for brown coals of high water content comprises, as seen in flow direction of the coal and one behind the other, a conveyor means (2) equipped with a means (3) for spraying hot waste water onto the coal, a wet sieve (4) equipped with a means (5) for supplying residual steam, a conveyor means (6) for conveying the sieved material to a pressure lock (7), a preheating means (8) equipped with a pressure lock (7) at the charging location and with connections for steam conduits (11), a further pressure lock (13) for discharging the coal from the preheating means (8) and for charging the coal into an autoclave (14) being adapted for being supplied with steam, preferably saturated steam, and having connected thereto waste water conduits (12), a sieve drum (15) arranged within the autoclave (14) and being equipped with a variable rotational drive means (16) and with conveyor elements, in particular screw conveyor elements, a further pressure lock (19) for discharging the steamed material into a subsequent drying means (20), a subsequent drying means (20) having a connection (22) for preheated gases such as steam, air or inert gases, and a means (23) for transporting away the dry coal.

Drying plant for brown coals of high water content

For drying organic solid materials, such as brown coals, the solid materials are, particularly for the purpose of immediately subsequent briquetting or refinement or gasification, respectively, preheated and introduced into an atmosphere of saturated steam at super-atmospheric pressure and increased temperature. After such a first drying stage (1, 2) operated with saturated steam, the process water formed in this drying stage is separated and the solid materials are at least partially pressure-released and subsequently further dried within an atmosphere of superheated steam at a temperature of at least 200.degree. C. of this steam atmosphere. The steam of this further drying stage (7) is passed along a closed circuit via heat exchangers (10, 11) and brought to or maintained at the required temperature. A portion of the steam passed along a closed circuit, that portion approximately corresponding to the amount of steam having its origin in the water content of the solid materials, is tapped via conduit (12) and used for preheating purposes (FIG. 1).

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Proleb, Austria

Franz W Mayer