Method for discharging delignified cellulosic materials from digesters

摘要

Lignocellulosic material, after delignification in an alkaline pulping liquor, can be removed from the digester in which it was pulped by first cooling the cooked material and relieving the overpressure from the digester, and then pumping the cooked material from the digester to a receiving vessel as a fluid suspension in spent liquor. When the fluid suspension is pumped at a low flow rate, the pulp thus obtained is superior in its physical properties to pulped material which is discharged under conventional conditions of high pressure and high flow rate from batch or continuous digesters.