| 摘要 |
A method and apparatus are provided for effecting treatment of sawdust to produce paper pulp in a simplified and effi-cient manner. The sawdust is entrained with liquid so that it forms a slurry having a consistency of between about 10-25%, and preferably between about 15-22% solids. The slurry consistency is maintained generally constant throughout the treatment process. The slurry at that consistency is pumped by a fluidizing, high speed. degassing, centrifugal pump (22). The pumping action alone provides for transport of the slurry to a digester vessel (40, 46). The digester vessel may be an upflow vessel, a hydraulically filled downflow vessel (40), or a superatmospheric vapor phase downflow vessel (40). Kraft pulping may be practiced in the digester, or a sulfite process may be practiced in the digester (46) and the slurry then passed to a refiner to produce a mechanical pulp. Between the pump and the digester the slurry passes through a heating device (30), which may comprise a fluidizing mixer for directly introducing high pressure steam into the slurry, or a pressure diffuser (30) for effecting indirect heating of the slurry. |
