Washing ~ Dirty Pulp to High Density Storage
Getting to the Washer
The Process
After pulp that at this point is black and and filled with weak black liquor, it is pumped through the Fibrilizer, Hot Stock Refiner, and Primary Hot Stock Screens.
The Fibrilizer removes large uncooked chips that are too big for the refiner. The Hot Stock Refiner refines the pulp to allow uncooked chips a chance , and the Primary Hot Stock Screens removes more large chips. There are re-circulation lines after the Primary Hot Stock Screens and Hot Stock Refiners that take pulp that isn’t ready for washing and puts it back into the blow tank.
There are #1 Primary Rejects Chest, #2 Primary Rejects Chest, Secondary Accepts Chest, and Secondary Rejects Chest that take rejects from the Primary Hot Stock Screens and either refine and send back to the blow tank or dispose off depending on further screening.
Defoamer is added before or after the Hot Stock Screens. Then finally the pulp can be sent to Washers #1–3. The defoamer is a silicone concentrate that helps with creating a vacuum seal in the washers and with drainage in the washers.
