CTMP Chip Maturation for Low-Extractives Food Packaging Pulp
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Chemithermomechanical pulp (CTMP) contains high levels of wood extractives such as triglycerides and fatty acids, which cause taste and odor issues, especially in food packaging applications, necessitating a reduction in extractives content.
Innovation Solution
Exposing wood chips to an aerobic environment at temperatures of 45-75 °C for at least 24 hours facilitates oxidative degradation of triglycerides into free fatty acids, which are easier to remove, followed by impregnation, heating, and refining steps to produce CTMP with reduced extractives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If wood chips are stored at elevated temperatures for extended periods to degrade extractives, then extractives content is reduced, but production time is increased
Solution Approach 1:
The patent applies preliminary action by storing wood chips at elevated temperatures (45-75°C) for 24-96 hours before the main CTMP processing. This pre-storage period allows oxidative degradation of triglycerides into free fatty acids, which are more easily removable. The preliminary thermal treatment prepares the chips for subsequent easier extractives removal during the actual pulping process.
Solution Approach 2:
The patent changes the temperature parameter during chip storage, maintaining chips at 45-75°C to accelerate oxidative degradation of extractives. This temperature parameter change facilitates the conversion of triglycerides to free fatty acids, making extractives more removable in subsequent processing steps without requiring extreme temperatures that would damage wood structure.
2Strength
If higher temperatures are used during heat treatment to improve CTMP quality, then bulk and strength are improved, but extractives removal becomes more difficult
Solution Approach 1:
The patent performs preliminary thermal storage at 45-75°C for 24-96 hours to convert triglycerides to free fatty acids before the main heat treatment. This preliminary action makes extractives more removable, allowing the subsequent high-temperature heat treatment to focus on improving CTMP strength and bulk without re-incorporating extractives.
Solution Approach 2:
The patent maintains continuous thermal action throughout the process - first through controlled storage at 45-75°C for extractive degradation, then through high-temperature heat treatment (140-200°C) for CTMP quality improvement. The thermal action continues seamlessly, with each phase preparing the material for the next, ensuring both extractives removal and product quality enhancement.
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 effectively reduces the extractives content in CTMP, enhancing its suitability for food packaging by minimizing taste and odor problems through oxidative degradation and improved extractives removal.
Implementation Method 1
Storing the chips at a temperature of 45-75 °C for at least 24h in an aerobic environment facilitates the production of a CTMP having a low extractives content. The storing enables oxidative degradation of triglycerides that are present in the wood chips.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present disclosure relates to a method for producing chemithermomechanical pulp, CTMP, comprising: a) providing wood chips comprising softwood, hardwood or a mixture thereof; b) storing the chips at a temperature of 45-75 °C for at least 24 h in an aerobic environment to obtain matured chips; c) impregnating the matured chips with an impregnation liquid to obtain impregnated chips; d) transferring the impregnated chips to a heating zone; e) heating the impregnated chips in the heating zone with steam to obtain pre-treated chips; f) defibrating the pre-treated chips to obtain a pulp; and g) dewatering the pulp.