METHOD FOR EXTRACTING HYDROLYSATE, BATCH COOKING SYSTEM AND HYDROLYSATE EXTRACTING ARRANGEMENT

Disclosed is a method for extracting hydrolysate in a batch cooking process for producing pulp. Said method comprises the steps: - providing lignocellulose raw material to a batch cooking vessel; - performing acid hydrolysis of the lignocellulose raw material in the batch cooking vessel; - displacing a first part of a hydrolysate from the batch cooking vessel by adding to the batch cooking vessel at least one first displacement liquid comprising recycled hydrolysate from a hydrolysate recirculation tank, wherein said recycled hydrolysate has been transferred to the hydrolysate recirculation tank from the batch cooking vessel during a previous batch cooking process; - receiving the first part of the hydrolysate in at least one hydrolysate extraction tank; - displacing a second part of the hydrolysate from the batch cooking vessel by adding to the batch cooking vessel at least one second displacement liquid comprising alkaline neutralization liquor; and - receiving the second part of the hydrolysate in a hydrol