| 摘要 |
1392770 Pulp manufacture TOYO PULP CO LTD 1 Jan 1973 [17 Jan 1972] 72/73 Heading D2W Pulp is made from fibrous raw material (a) by pre-cooking the raw material in an aqueous alkaline solution containing Na 2 CO 3 at 90- 190‹C, (b) mechanically defibrating the precooked material, and (c) pulping the defibrated material in a pressurised vessel at 90-170‹C in the presence of an oxygen-containing gas. As shown, wood chips may be fed from a hopper 1 into a pre-cooking digester 3 to which an alkaline cooking liquor containing Na 2 CO 3 may be fed via lines 4 and 20. The precooked chips may then be fed to a disc refiner 5 where they are defibrated. The defibrated 'material may then be fed to a pressurised vessel 8 via pump 7 and cooked therein with an aqueous alkaline solution in the presence of an oxygen-containing gas, the latter being introduced via line 10. The aqueous alkaline solution supplied to vessel 8 may stem directly from the pre-cooker and defibrator, or from the recovered liquors from wet-combustion vessel 17 via line 22. In addition, a dilute aqueous Na 2 CO 3 solution may be fed via line 23 from washer 14. Pulp formed in vessel 8 is pre-washed on a screen 11, and passed through line 12 to the washer via a cyclone 13. Waste liquors from vessel 8 are fed via line 15 to wet-combustion vessel 17 for treatment with oxygen-containing gas supplied via line 18. The alkaline aqueous solution recovered from vessel 17 may be recycled to the precooker 3 and/or vessel 8. CO 2 may be recovered via valve 19. |
