High yield chemical pulping and bleaching process
AssigneeGPCP IP Holdings LLC
InventorsJeffrey A. Lee, Kevin M. Holtman
Life of this patent
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Abstract
A method of producing high yield chemical cellulosic pulp includes: (a) chemically pulping wood chips to separate lignin and liberate cellulosic fibers from the wood chips to generate a cellulosic pulp; (b) washing and screening the pulp of step (a); (c) pre-treating the washed pulp with oxygen; (d) optionally washing the treated pulp of step (c); (e) bleaching the pre-treated pulp in an extended duration oxidative bleaching stage; (f) optionally washing the bleached pulp of step (e); and (g) optionally further oxidatively or reductively bleaching the bleached pulp in a shorter duration bleaching stage, wherein the bleached pulp is produced at a yield of greater than 60% based on the weight of the pulped wood chips (dry basis).
Claims18
A method of producing high yield chemical cellulosic pulp comprising:
- (a) chemically pulping wood chips in a Kraft Process to separate lignin and liberate cellulosic fibers from the wood chips to generate a cellulosic pulp;
- (b) washing and screening the cellulosic pulp of step (a) to generate a washed pulp;
- (c) pre-treating the washed pulp of step (b) with oxygen to generate a pre-treated pulp;
- and
- (d) bleaching the pre-treated pulp of step (c) in an extended duration oxidative bleaching stage in a bleaching vessel for a residence time of from 6 to 200 hours to generate a bleached pulp;
- wherein the bleached pulp of step (d) is produced at a yield of from 60% to 80% based on the weight of the wood chips in step (a) (dry basis).
Dependencies are inferred from the claim text.