Patent ID: 7658818

Claim:
A method for converting a vapor phase continuous digester to a hydraulic digester, wherein the vapor phase continuous digester comprises a digester vessel, a top separator in an upper section of the digester vessel, wherein the top separator includes a lower chip inlet port, a chip conveyor, a screen adjacent the conveyor, an upper chip discharge chute, and a liquor outlet facing a side of the screen opposite to the conveyor, and the digester vessel further includes a chip inlet conduit extending into the vessel and having a coupling to the lower chip inlet port, said method comprising: a. operating the digester vessel in a vapor phase mode wherein a chip slurry flows through a chip inlet conduit to the lower chip inlet port, moves up through the top separator, discharges from the upper chip discharge chute to an upper vapor region of the vessel, and falls to a liquor filled region of the vessel; b. ceasing the flow of the chip slurry to the lower chip inlet port; c. establishing a chip slurry flow path to feed the chip slurry to an upper portion of the top separator, and d. filling the vessel with liquor and chips such that the upper chip discharge chute is immersed in liquor.