Patent ID: 7459058

Claim:
A method for feeding a mixture of cellulose chips and fluid from a low-pressure system to a high-pressure system during the continuous cooking of chemical cellulose pulp, comprising: arranging a sluice feeder between the low-pressure system and the high-pressure system for sluice feeding fluid and cellulose chips, the sluice feeder having a first inlet, a second inlet, a first outlet and a second outlet defined therein, the sluice feeder having a rotor with a first pocket and a second pocket placed alternately in connection with the high-pressure system and the low-pressure system; placing the first pocket, located in a first position, in connection with a chip bin or with an impregnation vessel while filling the first pocket with a chips mixture and at the same time expelling fluid present in the first pocket via the first outlet; placing the second pocket, located in a second position, via the second outlet in connection with a transfer line in the high-pressure system while feeding the chips mixture out from the second pocket; transporting the chips mixture onwardly to a treatment vessel in the high-pressure system with an aid of a fluid that is fed into the second pocket through the second inlet; connecting the second inlet via at least one withdrawal line connected to the treatment vessel; withdrawing pressurized fluid from the treatment vessel; positioning the first pocket into the second position so that the first pocket is in connection with the high-pressure system; using the pressurized fluid to expel chips mixture from the first pocket when the first pocket is in connection with the high-pressure system; positioning the first pocket in the first position so that the first pocket is in connection with the low-pressure system; withdrawing previously pressurized fluid from the first pocket via the first outlet of the sluice feeder; forwarding the previously pressurized fluid, withdrawn from the first outlet, directly to a recovery system wherein the withdrawn previously pressurized fluid constituting at least 20% of a total amount (REC tot ) withdrawn for recovery, while being at least 1 m 3 /ton of pulp; and reducing a total amount of electrical energy required to pump a chips suspension from the low pressure system to the high pressure system through the sluice feeder.