Talc Adsorption for Papermaking Deposit Control
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Solution Overview
Problem
The papermaking process faces challenges with depositional materials such as oils, waxes, resins, and fatty acids, which build up on machinery and within the paper web, causing operational issues and quality defects like stickiness, breakage, and discoloration, and existing methods like alum and traditional retention aids have limited success in controlling these contaminants.
Innovation Solution
The introduction of talc into specific streams within the papermaking process, particularly those with low long fiber content and elevated depositional indices, where it interacts with and adsorbs hydrophobic contaminants, reducing their concentration and improving the hydrophilicity of the system, thereby reducing deposition and enhancing paper quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional retention aids and alum are used to control depositional material, then some contaminant removal is achieved, but the effectiveness is limited and deposits still build up on machinery
Solution Approach 1:
The patent changes the chemical parameter by substituting traditional retention aids and alum with talc, which has different surface properties and adsorption characteristics. This parameter change enables more effective removal of hydrophobic depositional materials that traditional chemicals cannot adequately control
Solution Approach 2:
Talc acts as an intermediary substance that adsorbs hydrophobic contaminants through its surface properties, facilitating their removal from the aqueous stream and preventing their deposition on machinery surfaces
2Productivity
If depositional material is allowed to accumulate in the aqueous stream, then processing continues without interruption, but deposition on machinery and within the paper web increases causing defects
Solution Approach 1:
The patent enables continuous operation by maintaining effective contaminant control throughout the process. Talc is added continuously to the aqueous stream, providing ongoing adsorption and removal of depositional materials, preventing both machinery buildup and paper defects without interrupting production
Solution Approach 2:
Talc serves as a continuous intermediary that mediates between the hydrophobic contaminants and the aqueous environment, enabling continuous removal of deposits while maintaining paper quality and operational continuity
3Object-affected harmful factors
If talc is added to aqueous streams with high long fiber content, then contaminant adsorption occurs, but the talc-fiber interaction reduces talc effectiveness and may cause retention issues
Solution Approach 1:
The patent applies local quality by selecting specific locations in the papermaking process where aqueous streams have low long fiber content for talc addition. This localized approach ensures that talc interacts primarily with contaminants rather than fibers, maximizing its effectiveness and simplifying process control
Solution Approach 2:
The patent changes the physical parameter of fiber content by selecting aqueous streams with low long fiber content as the target for talc addition, optimizing the interaction between talc and contaminants while minimizing talc-fiber interactions that would reduce effectiveness
4Object-affected harmful factors
If more traditional retention aids are used to control deposits, then some adherence control is achieved, but the complexity of the chemical system increases and effectiveness diminishes
Solution Approach 1:
The patent extracts the problematic traditional retention aids and alum from the chemical system and replaces them with a single, simpler substance—talc. This extraction simplifies the chemical system while improving effectiveness in controlling deposit adherence through talc's unique adsorption properties
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 use of talc significantly reduces depositional material content by at least 10-30% in aqueous streams, improves surface tension, reduces defects like holes and pinholes, and increases tensile strength and productivity by facilitating easier wet web release and improved retention of contaminants.
Implementation Method 1
contacting talc with an aqueous stream in the paper making process which is characterized by the aqueous stream having a low long fiber content
Data Source
AI summary
The present invention relates to a process for controlling deposits in a paper making process, more particularly to a process comprising the use of talc for controlling deposits in a paper making process with talc. One aspect of the invention is contacting talc with a white water stream at one or more locations within the paper making process after separating pulp from a pulp-containing stream and before introducing the re-circulating the white water stream to one or more of a pulper, a thick-stock, a thin-stock, a dilution process, a shower, a storage vessel, a blending process, and a digestor.