Patent ID: 6843885

Claim:
A method for controlling the cooking temperature in a continuous vapor phase digester for chip-shaped cellulose material, comprising: feeding chips and a cooking liquor to a top of the digester; establishing a chip level at the top of the digester; establishing a liquor level in a vapor phase below the chip level; mixing the chips with the cooking liquor and feeding the mixture into the top of the digester by means of steam in a sluice device, the steam having a steam pressure in the vapor phase exceeding 3 bar overpressure and a temperature exceeding 140° C., the mixture containing 40-70% of a cooking quantity of the cooking liquor required for cooking in the digester; feeding a temperature-controlled quantity of cooking liquor to the digester at the liquor level established in the digester, the quantity of the temperature-controlled cooking liquor being 30-60% of the cooking quantity for cooking, the temperature of the temperature-controlled cooking liquor being adjusted to a temperature at least 2° C. below a temperature in the vapor phase; cooking the chips in the digester with a liquor/chip ratio in a range of 3.5-6 kilogram of liquor per kilogram of chips; and withdrawing pulped cellulose fibers at a bottom of the digester.