PROCESS FOR REDUCING SPECIFIC ENERGY DEMAND DURING REFINING OF THERMOMECHANICAL AND CHEMI-THERMOMECHANICAL PULP

摘要

A method for producing thermomechanical or chemi-thermomechanical pulpis provided. The process is characterized as having a reduced specific energydemand during refining. The process involves processing a pretreated woodmaterial using one or more high consistency refining steps to produce a firstpulp, optionally applying a chelating agent to the first pulp during HCrefiningto produce a stabilized pulp and treating the first or stabilized pulp with analkaline-peroxide liquor to produce a treated pulp. The treated pulp is thenprocessed by one or more second low consistency refining steps. Alternatively,the first pulp or stabilized pulp may be divided into a primary and secondarystream. The primary stream is treated with alkaline-peroxide liquor to producea treated pulp. The secondary stream is processed using a secondary HCrefining step to produce a partially refined pulp, and removing latency of thepartially refined pulp and the treated pulp is removed in a common location.The treated pulp and the partially treated pulp is processed by one or morethanone second low consistency refining step to produce a final pulp. The methodsutilize less energy when compared with a method for producing pulp thatrequires both primary and secondary high consistency refining stages.