TH42745A - Method for the production of cellulose suspensions. - Google Patents

Abstract

DC60 is a process for the continuous production of cellulose suspensions in aqueous n-methylmorpholine n-oxide, characterized by (a) conveying of n-methylmorpholine n-oxide-free cellulose with homogenization through a first shear zone and (b) conveying of the homogenized cellulose through a second shear zone after the addition of a large amount of aqueous n-methylmorpholine n-oxide. After mixing the suspension with liquid-phase n-methylmorpholine n-oxide in the range of 70 to 80% by mass, the cellulose and suspension are formed, respectively, covering a cross-section ready for complete conveyance into the shear zone. This is characterized by (a) the conveyance of N-methylmorpholine N-oxide-free cellulose with homogenization through the first shear zone and (b) the conveyance of the homogenized cellulose through the second shear zone after the addition of a large amount of aqueous N-methylmorpholine N-oxide, which, after mixing the suspension with liquid-phase N-methylmorpholine N-oxide in the range of 70 to 80% by mass, is arranged so that the cellulose and suspension, respectively, cover a cross-section readily available for conveyance into the shear zone.

Claims (11)

1. The sequence of steps for the continuous production of cellulose suspensions in aquivalent N-methylmorpholine N-oxide is characterized as follows: (a) Cellulose is conveyed through the first shear zone without N-methylmorpholine N-oxide and is homogenized; and (b) The homogenized cellulose is conveyed through the second shear zone after the addition of sufficient aquivalent N-methylmorpholine N-oxide to the suspension, resulting in a liquid phase N-methylmorpholine N-oxide content of 70-80% by weight after mixing, while the cellulose or suspension is almost completely added, the conveying cross-section is ready for use in the shear zone. 2. A sequence of procedures consistent with claim 1 is characterized in which cellulose is sheared and transported in both shear zones along multiple axes with shear and transport elements aligned in the transport direction. 3. A sequence of procedures consistent with claim 2, which is specified to include two to eight axes for shearing and conveying. 4. A sequence of steps consistent with one of the claims of clauses 1-3 has been established, in which cellulose with a water content in the range of 20 to 80% by weight is used in step (a). 5. A sequence of steps consistent with one of the claims of clauses 1-4 has been established, in which the characteristic of primarily dry cellulose shall be used in step (a). 6. A sequence of steps consistent with one of the claims of clauses 1-5 is established, characterized by the use of aqueous nMMMO in step (b) with a molar ratio of nMMMO/H2O in the range of 1:1 and 1:2.2. 7. A sequence of steps consistent with one of the claims of clauses 1-6 is established, characterized by the addition of water to the cellulose and/or pre-treatment by enzymatic or aqueous heat before being used in step (a). 8. A sequence of procedures consistent with one of the claims of clauses 1-7 is defined, with the characteristic that procedures (a) and (b) are performed at temperatures in the range of 75 to 100°C. 9. A sequence of steps consistent with any of the claims of Articles 1-8 is established, characterized by the fact that both steps (a) and (b) proceed consecutively, and the suspension from step (b) is continuously discharged and fed into the decay step. 10. A sequence of steps consistent with any of the claims of clauses 1-9 is defined, with the characteristic that the total dwell time for steps (a) and (b) shall be 5-60 minutes. 11. A sequence of procedures consistent with one of the claims of clauses 1-10 is established, characterized by the additive being incorporated into the conveyed material.