Microfibrillated Cellulose Drainage Aids for Recycled Paper
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Solution Overview
Problem
Current papermaking systems face challenges in achieving optimal drainage performance, particularly in recycled paper grades, due to the presence of anionic contaminants which reduce the effectiveness of traditional drainage aids.
Innovation Solution
The use of microfibrillated cellulose in combination with coadditives such as cationic aqueous dispersion polymers, colloidal silica, bentonite clay, and vinylamine-containing polymers at the wet end of a paper machine enhances drainage performance, improving productivity and reducing energy demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional drainage aids are used in recycled paper grades, then drainage performance is reduced, but productivity is improved
Solution Approach 1:
The invention uses a composite drainage aid system comprising colloidal silica particles combined with cationic polyacrylamide polymer. This composite approach leverages the synergistic interaction between the inorganic silica particles and organic polymer to achieve effective drainage performance in recycled paper grades where traditional single-component aids fail due to anionic contaminants.
Solution Approach 2:
The invention modifies the chemical parameters of the drainage aid by using cationic polyacrylamide with specific molecular weights and charge densities that can effectively counteract the anionic contaminants in recycled pulp. The colloidal silica particles are also engineered with specific surface properties to enhance their interaction with the modified cellulose fibers.
2Productivity
If drainage rate is increased to improve productivity, then energy consumption at dry end increases
Solution Approach 1:
The drainage aids are applied in the wet end of the paper machine to pre-remove a significant portion of water before the slurry reaches the dry end. This preliminary drainage action reduces the water loading on the dry end evaporators, thereby reducing the energy consumption required for final water removal while maintaining high productivity.
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 combination significantly enhances drainage performance, leading to increased productivity and sustainability in papermaking operations by improving water removal efficiency and reducing energy consumption.
Implementation Method 1
The combination of both micropolymers and siliceous materials such as colloidal silica or bentonite clay can also be an effective drainage system
Data Source
AI summary
A process for the production of paper, board, and cardboard is disclosed. The process results in improved drainage and comprises adding to the wet end of a paper machine (a) microfibrillated cellulose and (b) a coadditive. The coadditive can be one or more of (1) a cationic aqueous dispersion polymer, (2) colloidal silica, (3) bentonite clay and (4) vinylamine-containing polymers or combinations thereof.