Abstract: The invention relates to a method and an impregnation vessel where the bulk volume of impregnation liquor added is in form of hot black liquor having a residual alkali content. Hot black liquor is added in an upper central pipe supplying the hot black liquor as impregnation liquor and flashing off steam for driving off air from the comminute cellulose material. During this first steaming is the wood acidity released from the material and spent impregnation liquor with wood acidity content is withdrawn from an upper withdrawal screen to recovery, a lower withdrawal screen recirculates the remaining impregnation liquor to a second lower central pipe in order to equalize the alkali content well before the remaining retention time in the impregnation vessel.

Abstract: The method is for the preparation of kraft pulp with increased pulping yield from lignin-containing cellulosic material using polysulfide cooking liquor. In order to increase carbohydrate stabilization and hence the yield from a kraft cooking process a first impregnation stage using polysulfide cooking liquor is implemented at high alkali and polysulfide concentration and at a low temperature. Knots are added to a high-pressure conduit extending between an impregnation vessel and a digester.

Abstract: The method is for the preparation of kraft pulp with increased pulping yield from lignin-containing cellulosic material using polysulfide cooking liquor. In order to increase carbohydrate stabilization and hence the yield from a kraft cooking process a first impregnation stage using polysulfide cooking liquor is implemented at high alkali and polysulfide concentration and at a low temperature. Knots are added to a high-pressure conduit extending between an impregnation vessel and a digester.

Abstract: The method is for the preparation of kraft pulp with increased pulping yield from lignin-containing cellulosic material using polysulfide cooking liquor. In order to increase carbohydrate stabilization and hence the yield from a kraft cooking process a first impregnation stage is using polysulfide cooking liquor implemented at high alkali and polysulfide concentration and at a low temperature.

Abstract: The method and arrangement are for adding treatment liquid to comminuted cellulose material, preferably wood chips, during the manufacture of chemical pulp in a continuous process. The process is using a down-flow vessel wherein chips are descending down the vessel in a plug flow and wherein treated chips are continuously fed out at the bottom of the vessel. By arranging at least one telescopic pipe inside the vessel that extends down into the plug flow makes it possible to adjust the position for the addition of treatment liquid depending on current operational parameters.

Abstract: The method and arrangement is for adding treatment liquor to comminuted cellulose material, preferably wood chips, during the manufacture of chemical pulp in a continuous process. The process uses a down-flow vessel where chips are descending down the vessel in a plug-flow and where treated chips are continuously fed out at the bottom of the vessel. By arranging more than two parallel pipes offset from the center of the vessel a better distribution of treatment liquor is obtained. Any disturbance of the chip plug flow descending down the vessel is reduced to a minimum.

Abstract: The method and arrangement are for adding treatment liquid to comminuted cellulose material, preferably wood chips, during the manufacture of chemical pulp in a continuous process. The process is using a down-flow vessel wherein chips are descending down the vessel in a plug flow and wherein treated chips are continuously fed out at the bottom of the vessel. By arranging at least one telescopic pipe inside the vessel that extends down into the plug flow makes it possible to adjust the position for the addition of treatment liquid depending on current operational parameters.

Abstract: The method and arrangement is for adding treatment liquor to comminuted cellulose material, preferably wood chips, during the manufacture of chemical pulp in a continuous process. The process uses a down-flow vessel where chips are descending down the vessel in a plug-flow and where treated chips are continuously fed out at the bottom of the vessel. By arranging more than two parallel pipes offset from the center of the vessel a better distribution of treatment liquor is obtained. Any disturbance of the chip plug flow descending down the vessel is reduced to a minimum.