Methods for carbonate pretreatment and pulping of cellulosic material

Inactive Publication Date: 2007-12-13
THE RES FOUND OF STATE UNIV OF NEW YORK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0019] One aspect of the invention may further include an oxygen delignification treatment as well as at least one bleaching stage, where the method produces a cellulosic pulp having a brightness greater than 88% elrepho. When an oxygen delignification treatment is provided, the method may produce a pulp having a lower kappa number after the oxygen delignification treatment at a predetermined screened y

Problems solved by technology

One disadvantage of soda cooking includes a lower pulp yield (for both softwoods and hardwoods) than realized by kraft cooking, that is, cooking using sodium hydroxide (NaOH) and sodium sulfide (Na2S) as the pulping chemicals.
Even with AQ addition, however, pulp from soda cooking processes exhibits weaker pulp strength and poorer bleaching compared to kraft cooking.
However, disadvantages also exist with soda anthraquinone (SAQ) cooking as compared to kraft cooking.
For instance, SAQ cooking requires higher amounts of NaOH and it is more difficult to bleach pulp produced from a SAQ pulping process.
These low MW organics are difficult to recover from the

Method used

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  • Methods for carbonate pretreatment and pulping of cellulosic material
  • Methods for carbonate pretreatment and pulping of cellulosic material
  • Methods for carbonate pretreatment and pulping of cellulosic material

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Embodiment Construction

[0029] The applicants have found that by treating comminuted cellulosic fibrous material, such as wood chips, in a first pretreatment stage with a carbonate compound, for example, substantially sulfur-free sodium carbonate, and then in a second pulping stage, for example, soda pulping in the presence of an anthraquinone (AQ used to symbolize any anthraquinones),—an improved pulp can be produced. An improved pulp is also produced if the pulp undergoes an acid treatment prior to a first pretreatment stage, followed by kraft pulping in the presence of an anthraquinone. For example, the pulp produced may be characterized by increased pulp yield, increased bleachability, higher strength, and lower rejects, among other beneficial properties.

[0030] Moreover, by treating the chips with a solution containing carbonate prior to treating the chips with pulping chemical, the amount of pulping chemical required in the pulping process for a desired treatment may be reduced. This development can ...

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Abstract

A method of pretreating comminuted fibrous material with sodium carbonate and then cooking the pretreated material in the presence of anthraquinone (AQ) is provided. The resulting pulp produced has a higher yield, enhanced strength, and better bleachability compared to pulp produced by prior art methods. AQ may also be introduced to the carbonate pretreatment stage. The method may further include an acid pretreatment providing further enhanced properties to the pulp produced.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority from co-pending provisional application Ser. No. 60 / 747,717, filed May 19, 2006, and co-pending provisional application Ser. No. 60 / 824,995, filed Sep. 8, 2006. The disclosures of these provisional applications are incorporated by reference herein.REFERENCE TO GOVERNMENT CONTRACTS [0002] This invention was made with government support under grant number CHE 0553323 entitled “An Investigation of Depolymerization and Condensation Reactions of Lignin Under Alkaline Conditions” awarded by the National Science Foundation. Accordingly, the United States government has certain rights in the invention.FIELD OF THE INVENTION [0003] The present invention relates to a process for treating comminuted cellulosic fibrous material, for example, wood chips, with a carbonate pre-treatment prior to cooking the cellulosic material with a cooking chemical in the presence of an anthraquinone (AQ). BACKGROUND OF THE INVENTION...

Claims

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Application Information

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IPC IPC(8): D21C3/26
CPCD21C1/04D21C9/147D21C3/222D21C3/02
Inventor FRANCIS, RAYMONDSHIN, NAM HEE
Owner THE RES FOUND OF STATE UNIV OF NEW YORK
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