Fractionating Saveall Whitewater Fiber Recovery
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Solution Overview
Problem
The papermaking industry faces challenges in managing whitewater, which results in the loss of usable fibers and operational issues due to high concentrations of fines, leading to degraded paper quality and machine performance, as conventional clarification technologies recover both usable fibers and fines, exceeding tolerance levels.
Innovation Solution
Implementing a Fractionating Saveall to separate usable fibers from particulate matter in the whitewater, allowing for the recirculation of only the usable fibers back into the whitewater system, while discharging the fines-laden fraction, thereby controlling fines concentrations and improving drainage and machine efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional clarification technologies (disk saveall or DAF) are used to recover whitewater solids, then usable fiber recovery is improved, but fines concentration increases beyond tolerance levels
Solution Approach 1:
The patent segments the solids recovery process into two distinct streams: a fiber-rich stream and a fines-rich stream. The disk saveall is operated at a first location to recover fibers, while a second disk saveall or DAF unit at a different location removes fines. This segmentation allows selective recovery of usable fibers while separately managing fines removal, resolving the contradiction between fiber recovery and fines control.
Solution Approach 2:
The patent introduces an intermediary clarification system between the whitewater source and the fiber recovery system. A first disk saveall or DAF unit acts as an intermediary to pre-clarify whitewater by removing a portion of fines before the water enters the main fiber recovery system. This intermediary step reduces the fines load on subsequent equipment, enabling effective fiber recovery without exceeding fines tolerance levels.
2Productivity
If all whitewater is recirculated to make stock, then water utilization is improved, but fines tolerance levels are exceeded
Solution Approach 1:
The patent segments the whitewater recirculation system into multiple pathways: a clarified stream that is recirculated to make stock, and a fines-rich stream that is discharged or sent to waste treatment. Disk savealls and DAF units create separate outlets for fiber-rich and fines-rich streams, allowing selective recirculation of only the beneficial portion while removing excess fines to maintain tolerance levels.
Solution Approach 2:
The patent applies selective discarding and recovering by discarding fines-rich streams while recovering and recirculating fiber-rich streams. The system identifies and separates the harmful component (fines) for disposal, while retaining and recycling the useful component (fibers). This selective approach maintains water utilization efficiency while preventing fines accumulation beyond tolerance levels.
3Loss of substance
If disk saveall or DAF clarification is used to recover whitewater solids, then fiber recovery is improved, but particulate matter pollution increases
Solution Approach 1:
The patent segments the solids separation process into multiple stages with different functions. The first disk saveall or DAF unit segments and removes fines, while subsequent units focus on fiber recovery. This multi-stage segmentation ensures that particulate matter pollution is controlled at the source, allowing effective fiber recovery without generating excessive pollution in any single stream.
Solution Approach 2:
The patent converts the harmful effect of fines accumulation into a benefit by using the fines-rich stream as a controlled discharge pathway. The system intentionally directs fines to designated discharge points or waste treatment systems, transforming what would be a pollution problem into a managed waste stream. This allows fiber recovery systems to operate effectively while controlling particulate matter pollution through deliberate routing of the fines-containing stream.
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 approach reduces fiber loss, enhances paper quality, and improves machine performance by isolating and removing particulate matter, allowing for effective volume control and efficient recirculation of usable fibers, thus addressing the issues of fiber loss and operational inefficiencies.
Implementation Method 1
a mechanical drainage aid to separate usable fiber from fines
Implementation Method 2
Fractionating Saveall to separate usable fibers from particulate matter in the whitewater
Data Source
AI summary
Methods and systems for reducing the loss of usable fibers from whitewater while simultaneously increasing paper making machine performance and paper quality are provided. The methods and systems utilize a fractionating saveall to separate whitewater into a dilute wastewater fraction that contains unwanted fine particles and a thicker consistency reusable fraction containing paper-forming fibers. The reusable fraction is recirculated back into the whitewater stream, while the wastewater is routed away from the whitewater stream.