Peroxide Bleaching Stabilizer Composition Without Silicate Scaling
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Solution Overview
Problem
The use of silicates in alkaline peroxide bleaching processes for pulp and paper production leads to severe precipitation problems, heat transfer issues in recovery boilers, and environmental concerns due to non-biodegradability and phosphorus contamination, necessitating a replacement that maintains bleaching effectiveness.
Innovation Solution
A composition comprising a copolymer of 3-allyloxy-2-hydroxypropanesulfonic acid (AHPS) with unsaturated carboxylic acids, combined with a chelating agent and poly-alpha-hydroxyacrylic acid or its alkaline salt, acts as a stabilizer in bleaching processes, replacing silicates and improving bleaching performance, especially in mechanical and de-inked pulps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicates are used as stabilizers in alkaline peroxide bleaching processes, then peroxide stability is improved, but severe precipitation problems occur and heat transfer efficiency decreases in recovery boilers
Solution Approach 1:
The invention extracts and removes silicates from the bleaching process by replacing them with alternative stabilizing agents (polymer compounds and chelating agents), thereby eliminating the harmful precipitation and scaling effects while maintaining peroxide stability
Solution Approach 2:
The invention changes the chemical composition parameters by substituting silicate-based stabilizers with polymer-based stabilizers (containing carboxylic acid groups) combined with chelating agents, fundamentally altering the stabilization mechanism from silicate precipitation to polymer-chelate complex formation
2Reliability
If common chelating agents such as EDTA and DTPA are used, then metal ion removal is improved, but biodegradability deteriorates and environmental impact increases
Solution Approach 1:
The invention employs biodegradable polymer-chelating agent complexes that can be naturally decomposed, replacing persistent synthetic chelators with environmentally friendly alternatives that break down into harmless substances, effectively addressing the non-biodegradability issue
Solution Approach 2:
The invention creates a composite system combining polymers with carboxylic acid groups and chelating agents, where the polymer backbone provides structural framework and the chelating groups provide metal binding capability, achieving both effectiveness and biodegradability
3Reliability
If water glass is used for stabilizing hydrogen peroxide solutions, then peroxide stability is improved, but severe scaling occurs in recovery boilers and evaporation units
Solution Approach 1:
The invention extracts water glass (silicate) from the stabilization process and replaces it with organic polymer stabilizers, eliminating the scaling problem that causes heat transfer inefficiency in recovery boilers and evaporation units
Solution Approach 2:
The invention introduces polymer-chelating agent complexes as intermediary substances that mediate between peroxide and metal ions, providing stabilization without forming insoluble precipitates that would interfere with heat transfer processes
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 achieves effective bleaching with reduced energy requirements for dewatering and increased production throughput, while minimizing environmental impact by avoiding silicate-related issues and maintaining high brightness and residual peroxide levels.
Implementation Method 1
chelating agents can be used as pretreatment for removing harmful metal ions... hydrogen peroxide will decompose very rapidly in an alkaline milieu in the presence of transition metal ions
Implementation Method 2
bleaching with a peroxygen compound of chemical, mechanical, chemi-mechanical and de-inked pulps... bleaching of fiber material with a peroxide compound
Data Source
AI summary
The invention relates to a stabilizing composition comprising following components(A) a polymer having the following formula:whereinR1 is a hydrogen atom or an alkyl group containing 1 to 12 carbon atoms,R2 is —COOM or —CH2COOM,M is a hydrogen atom, an alkali metal ion, an alkaline earth metal ion, an ammonium ion or a mixture thereof,n, m and k are molar ratios of corresponding monomers, wherein n is 0 to 0.95, m is 0.05 to 0.9, and k is 0 to 0.8, and (n+m+k) equals 1, andthe weight average molecular weight is between 500 and 20,000,000 g/mol,(B) a chelating agent,(C) a poly-alpha-hydroxyacrylic acid or an alkaline salt thereof or the corresponding polylactone thereof, and(D) optionally a polycarboxylic acid polymer or an alkaline salt thereof.The invention also relates to a process for the treatment of a fiber material.