Oxygen Delignification Additive Composition for Cellulose Protection
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Solution Overview
Problem
Current methods for oxygen delignification of chemical wood pulps result in high cellulose degradation and reduced pulp quality due to harsh conditions, leading to lower fiber strength and yield, with a need for improved additives to enhance delignification efficiency and protect cellulose integrity.
Innovation Solution
A composition comprising organic amine phosphonates, sulphonated linear alcohol ethoxylates, and optionally magnesium salts is added to Kraft pulp before a 2-stage oxygen delignification process to enhance lignin removal while protecting cellulose viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If harsh conditions (higher temperature, higher alkalinity, longer time) are used to reduce lignin content, then lignin removal efficiency is improved, but cellulose depolymerization increases and pulp quality deteriorates
Solution Approach 1:
Magnesium salts serve as a protective intermediary substance that mediates between the harsh oxygen delignification conditions and the cellulose chains. The magnesium ions form protective complexes with cellulose, preventing oxidative cleavage while allowing lignin removal to proceed efficiently under aggressive conditions.
Solution Approach 2:
The invention changes the chemical environment by introducing magnesium salts that alter the reaction parameters. The presence of magnesium ions modifies the oxidative environment, reducing the harmful effects on cellulose while maintaining effective lignin delignification through controlled chemical interactions.
2Strength
If magnesium salts are used to protect cellulose during oxygen delignification, then pulp strength is maintained, but chemical additive cost and environmental impact increase
Solution Approach 1:
The invention optimizes the concentration and form of magnesium salts to achieve effective protection at reduced levels. By changing parameters such as magnesium salt concentration, addition timing, and process conditions, the patent minimizes chemical usage while maintaining pulp strength protection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves higher lignin removal with maintained pulp strength and yield, reducing the need for magnesium salts and improving environmental performance by minimizing phosphorus and nitrogen-containing chemical use.
Implementation Method 1
Chemical wood pulps are generally delignified using pressurized oxygen (oxygen delignification) to reduce the lignin content by 40-70%
Implementation Method 2
The fundamental chemical reactions, industrial application of the process, and the limitations just described are reviewed in; McDonough, Thomas J., Oxygen Delignification, Chapter IV-1 in; Pulp Bleaching. Principles and Practices, Dence & Reeve Eds. 1996
Data Source
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AI summary
A method for producing a high yield Kraft pulp is provided. In particular, the method involves adding a composition comprising an organic amine phosphonate and a sulphonated linear alcohol ethoxylate surfactant to a pulping process. The composition enhances the delignification of cellulosic fiber in chemical wood pulps.