Continuous Digesters

With a continuous digester, steamed chips and liquor are fed into the pressurised digester. These contents are heated up by various circulation systems as they move downwards. The cooked and partially washed pulp is fed out of the bottom of the digester.

The spent cooking liquor known as black liquor is separated by screens around the digester and is then directed to the flash tanks where the pressure is decreased to below vapour pressure. The steam generated is used for steaming of the chips and the black liquor is then sent through to the evaporation process.

Continuous digesters mainly use the sulphate process, which is often referred to as the Kraft Process of Kraft Pulping.

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