On-Site Polyacrylamide Glyoxylation With Viscosity End-Point Control
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Solution Overview
Problem
Existing methods for manufacturing glyoxylated polyacrylamide on-site face challenges in maintaining consistent quality and throughput, with issues such as storage instability and gel formation, especially for high molecular weight polymers, leading to high transportation and storage costs.
Innovation Solution
A method for on-site glyoxylation of polyacrylamide in a paper or board mill using a discontinuous batch reaction in a reactor vessel with a driven agitator, where alkali consumption is determined beforehand to adjust pH, and viscosity is monitored to control the reaction, eliminating the need for complex pH measurements and reducing reaction time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glyoxylated polyacrylamide is manufactured on-site using existing methods, then the strength properties of paper and board are improved, but the reaction time is extended and quality consistency deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-determining the alkali consumption of the reaction mixture before the glyoxylation reaction begins. This allows for precise pH adjustment without requiring complex real-time pH measurements during the reaction, thereby reducing reaction time while maintaining product quality consistency. The alkali consumption is calculated based on the specific properties of the polyacrylamide base polymer and glyoxal used, enabling optimized reaction conditions to be established in advance.
2Strength
If high molecular weight polyacrylamide is used to improve strength properties, then the strength improvement efficiency increases, but the risk of gel formation and storage instability increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the pH value during the glyoxylation reaction. By determining the alkali consumption beforehand and adjusting the pH to optimal levels, the reaction conditions are optimized to prevent excessive cross-linking that leads to gel formation. This allows high molecular weight polyacrylamide to be effectively crosslinked to improve strength properties while maintaining storage stability by keeping the cross-linking reaction under control.
3Manufacturing precision
If complex pH measurement and control systems are used during glyoxylation, then the manufacturing precision improves, but the device complexity and cost increase
Solution Approach 1:
The patent eliminates complex pH measurement systems by performing preliminary calculation of alkali consumption before the reaction. Instead of requiring real-time pH monitoring and adjustment during glyoxylation, the method calculates the exact amount of alkali needed based on the known properties of the reactants, simplifies the control system while maintaining manufacturing precision.
Solution Approach 2:
The reaction mixture essentially self-regulates the pH through the predetermined alkali addition. The system uses the inherent chemical properties of the polyacrylamide base polymer and glyoxal to determine alkali consumption, eliminating the need for external complex monitoring and control systems. The process becomes more autonomous and less dependent on sophisticated instrumentation.
4Productivity
If the reaction cycle is shortened to improve productivity, then the throughput increases, but the risk of inadequate cross-linking and gel formation increases
Solution Approach 1:
By pre-determining the alkali consumption and optimizing the pH adjustment before the reaction begins, the patent creates optimal conditions for rapid and complete cross-linking. This preliminary optimization allows the reaction to proceed efficiently and completely in a shorter time, improving throughput without sacrificing reaction completeness or risking gel formation from uncontrolled cross-linking.
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 enables the production of glyoxylated polyacrylamide with enhanced strength properties, particularly in humid conditions, reducing the risk of gel formation and improving the efficiency of paper and board production by shortening the reaction cycle without compromising quality.
Implementation Method 1
Glyoxylated polyacrylamide is formed by crosslinking polyacrylamide-based polymers by using glyoxal
Implementation Method 2
adding to the reaction mixture, on the basis of the determined alkali consumption, a pre-determined amount of alkali which is needed for adjusting the reaction mixture's pH value within a range of 8-10
Implementation Method 3
adding acid to the reaction mixture for lowering the pH value of the reaction mixture
Implementation Method 4
a reactor vessel provided with a driven agitator
Implementation Method 5
measuring viscosity of the reaction mixture and/or a process variable that is related to the viscosity of the reaction mixture
Data Source
AI summary
Disclosed is method for on-site glyoxylation of polyacrylamide in a paper or board mill, where a discontinuous batch glyoxylation reaction of aqueous reaction mixture is performed in reactor vessel having driven agitator to form aqueous polymer composition comprising glyoxylated polyacrylamide. The method comprises forming or obtaining the aqueous reaction mixture comprising polyacrylamide base polymer and glyoxal, determining alkali consumption of the mixture, and adding to the mixture, based on determined alkali consumption, pre-determined amount of alkali for adjusting pH to 8-10. The temperature is optionally adjusted to 15-40° C. and the on-site glyoxylation reaction of polyacrylamide base polymer is allowed to proceed. Viscosity of the mixture and/or a variable related to the viscosity is measured, acid is added to the mixture for lowering pH to <8, when a predetermined end viscosity value is attained, and the aqueous polymer composition comprising glyoxylated polyacrylamide is removed from the reaction vessel.