초록 ▼

Calcium containing sulphate spent liquor is deactivated by means of heating. Spent liquor is heated by means of direct condensing in a flash-steam-system. Liquor vapors generated during expansion of the already deactivated spent liquor are used for heating the spent liquor. Spent liquor is led to a

Calcium containing sulphate spent liquor is deactivated by means of heating. Spent liquor is heated by means of direct condensing in a flash-steam-system. Liquor vapors generated during expansion of the already deactivated spent liquor are used for heating the spent liquor. Spent liquor is led to a retention tank through n+1 in series connected direct condensers (DK I-DK V) and from the retention tank through n in series connected flash tanks (FT I-FT IV) disposed counter-currently to the direct condensers. In the last one of the direct condensers (DK V) the liquor is heated by means of externally supplied steam; in all others (DK I-DK IV) by means of expansion vapor.

대표청구항 ▼

Apparatus for deactivating spent liquor, comprising: a plurality of flash tanks for expanding deactivated liquor, comprising n flash tanks connected in series, wherein n is a positive integer; a plurality of direct condensers, comprising n+1 direct condensers, connected in series including a first c

Apparatus for deactivating spent liquor, comprising: a plurality of flash tanks for expanding deactivated liquor, comprising n flash tanks connected in series, wherein n is a positive integer; a plurality of direct condensers, comprising n+1 direct condensers, connected in series including a first condenser into which undeactivated spent liquor is fed, and a last condenser from which undeactivated spent liquor flows; each of said flash tanks comprising a vapor generating portion, said vapor generating portion of each of said flash tanks operatively connected to one of said condensers for direct heating of said undeactivated spent liquor, except said last condenser; and the liquor flowing from said last condenser operatively connected to a retention tank disposed between said last condenser and a liquor inlet to a first of said series of flash tanks. A method for deactivating calcium containing black liquor obtained from the cooking of comminuted cellulosic fibrous material comprising the steps of: (a) feeding undeactivated black liquor under pressure through a plurality of direct condensers arranged in series from first to last, and from the last direct condenser to a retention tank where said black liquor is deactivated by precipitation of the calcium; (b) during step (a), increasing the pressure successively between each of the plurality of direct condensers; (c) discharging deactivated spent liquor from said retention tank to a plurality of flash tanks arranged in series from first to last, wherein in each of said flash tanks, said deactivated liquor is partially vaporized; and (d) utilizing vapor formed in each of said flash tanks to heat undeactivated liquor in said direct condensers, wherein the direction of flow of said deactivated liquor is counter the direction of flow of said undeactivated liquor, and wherein the vapor from the first of said series connected flash tanks supplies heat to the next-to-last direct condenser, and the vapor from the last of said series connected flash tanks supplies heat to the first direct condenser.