Method and system for high alpha dissolving pulp production

Abstract

A method for pulp processing used in connection with a pre-hydrolysis kraft process (PHKP) includes adding wood chips or similar material to a reaction vessel, performing pre-hydrolysis, and neutralizing the mixture with a first quantity of white liquor followed by a different solution such as a cold caustic extraction alkaline filtrate optionally enriched with white liquor. The neutralization fluids are replaced with a cooking fluid comprising a hot black liquor and alkaline filtrate, optionally enriched with white liquor. The cooking fluid may have a relatively high effective alkali concentration. The cooked pulp may exhibit very low residual hemicelluloses and a kappa number within an optimal range.

1 .- 34 . (canceled) 
     
     
         35 . A semi-purified pulp derived from plant matter, said semi-purified pulp having a residual hemicelluloses content of less than 3.0 percent as measured in terms of S18 solubility and a kappa number of greater than 8 after cooking but before cold caustic extraction 
     
     
         36 . The semi-purified pulp of  claim 35 , wherein the plant matter is a hardwood. 
     
     
         37 . The semi-purified pulp of  claim 35 , wherein, after cold caustic extraction but before bleaching, the residual hemicelluloses content is no greater than 1.7 percent as measured in terms of S18 solubility and the kappa number is no less than 9. 
     
     
         38 .- 42 . (canceled)