Abstract: A method of producing chemical pulp including at least the following steps: a) wood chips or other comminuted ligno-cellulosic fibrous material is treated with a polysulfide-containing cooking liquor in an impregnation stage at a temperature of 90-145° C., and b) slurry of fibrous material from step a) is heated into cooking temperature and cooked for producing pulp having a desired kappa number. After step a) mercaptide ions are added into the slurry of fibrous material and the fibrous material is treated at cooking temperature in step b).

Abstract: A method of producing chemical pulp including at least the following steps: a) wood chips or other comminuted ligno-cellulosic fibrous material is treated with a polysulfide-containing cooking liquor in an impregnation stage at a temperature of 90-145° C., and b) slurry of fibrous material from step a) is heated into cooking temperature and cooked for producing pulp having a desired kappa number. After step a) mercaptide ions are added into the slurry of fibrous material and the fibrous material is treated at cooking temperature in step b).

Abstract: A method of defibring lignocellulose-bearing raw material with a polysulphide-bearing cooking liquor in a continuous digester. The cooking liquor is mixed into the raw material which is to be defibred before the cooking, and the cooking liquor is allowed to absorb into the raw material at a temperature which is at maximum approximately 130° C. The cooking liquor is then separated from the treated raw material, heated to a temperature of approximately 140-170° C., and mixed back into the treated raw material, possibly together with a fresh feed of cooking liquor, whereby the raw material is defibred to generate pulp which has a desired kappa number.

Abstract: A method of defibring lignocellulose-bearing raw material with a polysulphide-bearing cooking liquor in a continuous digester. According to the present invention, cooking liquor is mixed into the raw material which is to be defibred before the cooking, and the cooking liquor is allowed to absorb into the raw material at a temperature which is at maximum approximately 130° C. After that, cooking liquor used for the absorption is separated from the raw material which is treated in this way, the separated cooking liquor is heated to a temperature of approximately 140-170° C., after which the generated hot cooking liquor is mixed back into the treated raw material, possibly together with a fresh feed of cooking liquor fresh feed, and the raw material is defibred by means of the hot cooking liquor in a continuous digester in order to generate pulp which has a desired kappa number.

Abstract: A method and apparatus for treating pulp in connection with a blow tank or a storage tank. The pulp is discharged from a batch digester and fed either to the upper or the lower part of a blow tank, depending on the consistency of the pulp being discharged from the digester.

Abstract: A method and apparatus for treating pulp in connection with a blow tank or a storage tank. The pulp is discharged from a batch digester and fed either to the upper or the lower part of a blow tank, depending on the consistency of the pulp being discharged from the digester.

Abstract: A method and apparatus for treating pulp being fed into a blow tank or a storage tank. A preferred embodiment is that the pulp is discharged from a batch digester (10) and fed either to the upper or lower part of a blow tank (20), depending on the consistency of the pulp being discharged from the digester.

Abstract: Processes for preparing pulp from lignin-containing cellulosic material are disclosed including a prehydrolysis step followed by neutralizing hydrolysate and the prehydrolyzed cellulosic material in the reactor with alkaline neutralizing liquor, removing the neutralized hydrolysate from the reactor and delignifying the neutralized prehydrolyzed cellulosic material with alkaline cooking liquor containing sodium sulfide and sodium hydroxide.