Ahlstrom Machinery, Inc.

Ahlstrom Machinery Oy

Jouni Jantti

Holger Engdahl

Holgor Engdahl

Juhani Vehmaan-Kreula

Pasi Vanttinen

Kurt Siren

Method of separating impurities from lime and lime sludge

A method of regulating the temperature in a chemical melt dissolving tank, where chemical melt produced in combustion of spent liquor of a cellulose pulp mill is dissolved in liquid, producing green liquor, provides excellent heat economy, while minimizing the amount of liquid needed to dissolve the melt to produce green liquor at a temperature below boiling. Green liquor produced in the dissolving tank is expanded (and thereby cooled) in a vacuum tank, and a least a significant part of the cooled liquor is returned to the dissolving tank, for regulating the temperature in the tank. The heat energy contained in the generated expansion steam may be used in many different ways, for example, for indirectly heating (e.g. in a heat exchanger acting as a condenser) water or other liquid to a sufficiently high temperature so that the liquid is useful elsewhere in the pulp mill. The vacuum tank may be positioned above dissolving the tank to receive liquor directly from it, and the condenser may be positioned in it to return condensate directly to the dissolving tank. Alternatively the vacuum tank and condenser may be remote from the dissolving tank and connected to the dissolving tank by conduits.

Method and apparatus for regulating the temperature in a chemical melt

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Savonlinna, Finland

Jouni Jantti