US 4,071,399 A · Apparatus and method for the displacement impregnation of cellulosic chips material

Abstract

An apparatus and method for the displacement impregnation of cellulosic chips material with digesting liquid. Cellulosic chips material and liquid are fed from a source to a high pressure transfer valve whereat the pressure of the chips and liquid is boosted. The chips are fed from the high pressure transfer valve through a feed system to the topmost portion of a vertical treatment vessel, the vessel having a topmost portion and an impregnation zone in an upper portion thereof below the topmost portion. A countercurrent flow of digesting liquid in the vessel impregnation zone is established to impregnate the chips material with digesting liquid, and displace the water and minerals therefrom, and liquid withdrawn from the top of the treatment vessel is withdrawn into the feed system. The withdrawals insure that essentially no free water enters the impregnation zone. A chips plug is established at the vessel top through which all withdrawn liquid must pass. Digesting liquid may be supplied to an end portion of the high pressure treatment valve for maintaining the pH of liquid around the high pressure transfer valve at 8 or above.

Claims15

Dependent claims

Apparatus for treating cellulosic chips material comprising

a. a high-pressure transfer valve for transporting cellulosic chips and liquid under pressure,
b. a high-pressure vertical treatment vessel having at least an impregnation zone in an upper portion thereof, and a top chamber above the impregnation zone,
c. a chips and liquid inlet to said top chamber of said vessel,
d. a feed system for feeding chips and liquid to said inlet and for returning liquid from said inlet to said high-pressure transfer valve, said feed system including conduits extending from said top chamber to said transfer valve,
e. means for establishing a countercurrent flow of digesting liquid in said impregnation zone of said vessel liquid, said means including means for withdrawing liquid from said impregnation zone through said top chamber of said vessel into said feed system,
f. means for withdrawing liquid from said feed system;
so that essentially no free water enters said vessel impregnation zone,
g. means for withdrawing treated chips material from the bottom of said vessel, and
h. means for establishing a chips plug in said vessel below said inlet for isolation of said top chamber of said vessel from the impregnation zone thereof, said means for withdrawing liquid from said impregnation zone through said top chamber of said vessel including an outlet disposed above said chips plug in the top chamber of said vessel.

6 more elements

A method for treating cellulosic chips material utilizing high-pressure transfer valve connected by a feed system to at least one vertical treatment vessel having a top chamber, comprising the steps of continuously

a. feeding chips material and liquid to the high-pressure transfer valve to boost the pressure thereof,
b. transporting said high-pressure chips material and liquid to the top chamber of the vertical treatment vessel and introducing said chips into the top chamber of the vessel from the feed system, to establish a column of chips in the vessel below said top chamber of the vessel,
c. establishing a countercurrent flow of digesting liquid in the vessel impregnation zone to displace water, calcium and other minerals from the chips material, while impregnating the chips material with digesting liquid, by withdrawing liquid from said impregnation zone through said top chamber of the vessel into the feed system,
d. withdrawing liquid, including the displaced water, calcium, and other minerals, from the feed system;
the withdrawals practiced in steps (c) and (d) insuring that essentially no free water enters the vessel impregnation zone, and
e. withdrawing treated chips material from the bottom of the vessel.

3 more elements

Dependencies are inferred from the claim text.

Apparatus and method for the displacement impregnation of cellulosic chips material

Life of this patent

Apparatus and method for the displacement impregnation of cellulosic chips material

Life of this patent

Abstract

Claims15