Cotton Pulping with Oxygen and Alkaline Control
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Solution Overview
Problem
Current methods for producing dissolving pulp from cotton-based raw materials are inefficient, environmentally harmful, and limited in their ability to produce high-quality pulp suitable for downstream applications like lyocell and viscose production, due to high energy consumption, chemical usage, and inability to control intrinsic viscosity and brightness effectively.
Innovation Solution
A method involving pulping cotton-based raw materials in an alkaline solution with a gaseous oxidizing agent, such as oxygen, at controlled temperatures and pressures, in the presence of a cellulose-stabilizing additive, allowing for the production of high-quality dissolving pulp with specific properties suitable for regenerated cellulose molded bodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high reaction temperatures above 150°C are applied to remove impurities from cotton linters, then the purification effectiveness is improved, but cellulose degradation increases causing substantial yield loss
Solution Approach 1:
The patent changes the temperature parameter from above 150°C to 100-185°C range, and introduces pressure parameter (1-21 bar) and pH parameter (9-13) control to achieve effective purification without excessive cellulose degradation, resolving the contradiction between purification effectiveness and yield loss
Solution Approach 2:
The patent introduces an alkaline solution as an intermediary medium that facilitates impurity removal at moderate temperatures through chemical action, reducing the need for high temperature thermal degradation and thereby minimizing cellulose yield loss
2Manufacturing precision
If multi stage bleaching processes are used to achieve required brightness levels, then the brightness quality is improved, but environmentally harmful chemicals are released
Solution Approach 1:
The patent converts the harmful multi-stage bleaching process into a beneficial single-stage process by using controlled alkaline treatment with oxygen at moderate temperatures, achieving required brightness levels without releasing environmentally harmful chemicals
Solution Approach 2:
The patent extracts and removes harmful chemicals from the process by replacing traditional multi-stage bleaching with a single-stage alkaline treatment using oxygen, eliminating the need for harmful substances like chlorine compounds and hydrogen peroxide
3Manufacturing precision
If extensive use of process chemicals is applied to remove impurities, then the purification effectiveness is improved, but the process complexity and cost increase
Solution Approach 1:
The patent applies a universal alkaline solution treatment that simultaneously achieves multiple objectives: impurity removal, brightness enhancement, and viscosity control in a single process stage, reducing process complexity while maintaining purification effectiveness
Solution Approach 2:
The patent optimizes process parameters (temperature 100-185°C, pressure 1-21 bar, pH 9-13, time 45-270 minutes) to achieve effective purification with reduced chemical usage, simplifying the process while maintaining effectiveness
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
This method reduces energy consumption, eliminates the need for harmful bleaching chemicals, and enables the production of dissolving pulp with high ISO brightness and controlled intrinsic viscosity, making it suitable for various downstream applications like lyocell, viscose, and modal processes.
Implementation Method 1
cellulose degradation reactions occur and lead to a substantial loss of yield
Implementation Method 2
treated under harsh conditions in order to remove impurities
Implementation Method 3
heating the pulping mixture to a temperature above ambient temperature
Data Source
AI summary
The present invention relates to a method of pulping cotton-based raw material for producing dissolving pulp. More specifically, the invention relates to a process for producing dissolving pulp under alkaline conditions in combination with a gaseous oxidizing agent. The present invention further relates to dissolving pulp obtainable by pulping cotton-based raw material, in particular dissolving pulp obtainable by the method of the present invention, the use of such dissolving pulp for producing regenerated cellulose molded bodies, and methods of producing lyocell or viscose including such dissolving pulp.