Method for improved turpentine recovery from modern cooking plants
AssigneeMetso Paper Pori Oy
InventorsPaivi Uusitalo, Mikael Svedman, Jukka Vaistomaa, Hannu Haaslahti
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Abstract
A method for the preparation of pulp by means of alkaline cooking, in which method spent liquor is transferred to pressurized tanks, and at least one liquor is expanded corresponding to a temperature difference of 1 to 5° C. The generated steam is led to turpentine recovery. Thus, the removal of turpentine and gases dissolved in said liquor is effective, the amount of recovered turpentine increases, and pulp of better washability and higher quality is obtained.
Claims9
An improved method for producing chemical pulp from lignocellulosic material by means of alkaline cooking, said method including cooking the material in a digester and conduction of spent liquors displaced from the digester to pressurized tanks, characterized in that at least one of the spent liquors displaced from the digester is caused to expand against a pressure corresponding to a temperature about 1° C. to about 5° C. lower than the boiling temperature of the liquor prior to expansion, and the vapor resulting from the expansion is conducted to turpentine recovery.
A method according to any claim 46, characterized in that a non-tight barrier for reducing mixing is provided between the liquid inlet and liquid outlet in the tank, the inlet for the heating circuit being on the tank inlet side and the heating circuit outlet being on the tank outlet side of the barrier.
Dependencies are inferred from the claim text.