Refiner Plates With Steam Channels For Backflow Extraction
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Solution Overview
Problem
Mechanical pulping processes face a high energy cost due to the need for extensive production of high pressure steam, with existing low-energy refiner plates only capturing a limited amount of high pressure steam for reuse, leading to increased energy consumption.
Innovation Solution
The development of refiner plates with steam channels that facilitate the backflow of high pressure steam, allowing it to be extracted and reused within the refining system, reducing the need for fresh steam generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional low-energy refiner plates are used to reduce energy consumption, then energy cost is reduced, but the amount of high pressure steam available for reuse is limited
Solution Approach 1:
The refiner plate is segmented into multiple refining zones with different bar configurations. The first refining zone has bars configured to generate high pressure steam, while the second refining zone has bars optimized for fiber refinement. This segmentation allows the plate to simultaneously produce sufficient high pressure steam for reuse while maintaining low energy consumption for the overall refining process.
Solution Approach 2:
Different regions of the refiner plate have locally optimized bar characteristics. The first refining zone features bars with specific spacing and orientation designed to maximize steam generation through frictional heating, while the second refining zone has bars configured for efficient fiber separation. This local quality differentiation ensures that steam generation occurs primarily in the first zone without significantly increasing overall energy consumption.
2Quantity of substance
If fresh steam is produced to meet high pressure steam needs, then sufficient steam supply is ensured, but energy consumption increases
Solution Approach 1:
The system recovers high pressure steam that would otherwise be discarded or vented during the refining process. The refiner plate design captures steam generated in the first refining zone and directs it through steam channels to a steam recovery system, where it is collected and reused for chip steaming or other process requirements, eliminating the need to generate additional fresh steam.
Solution Approach 2:
The refining process itself generates the high pressure steam needed for process operations through frictional heating of wood chips between the refiner plates. The system is designed to capture and reuse this self-generated steam, making the process self-sufficient for steam requirements without relying on external steam generation facilities.
3Manufacturing precision
If refiner plates are designed to maximize fiber refinement, then pulp quality is improved, but high pressure steam generation is reduced
Solution Approach 1:
The refiner plate is divided into two distinct refining zones with different bar configurations optimized for different functions. The first zone generates high pressure steam through intense frictional heating, while the second zone provides gentle refinement to achieve the desired pulp quality. This segmentation allows both steam generation and pulp quality improvement to occur without compromising either objective.
Solution Approach 2:
The first refining zone performs preliminary steam generation and chip softening through frictional heating before the material enters the second refining zone. This preliminary action prepares the chips for more efficient refinement in the second zone, allowing the system to achieve high pulp quality while maintaining adequate steam generation in the first zone.
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 solution increases the availability of high pressure steam for other uses in the refining plant, thereby reducing energy requirements and costs by capturing more steam than traditional low-energy plates.
Implementation Method 1
The refining process also generates high frictional forces that causes water in the chip feed material to convert to high pressure steam
Implementation Method 2
High pressure steam is needed in the feeding side of the refiner... High pressure steam for refining is usually provided a combination of back-flowing steam from the refiner
Data Source
AI summary
A refining plate for refining lignocellulosic material including: a radially outer peripheral edge and a substrate surface; a refining zone having a plurality of substantially radially disposed bars and grooves between the bars, wherein the bars protrude upward from the substrate surface and the grooves each have a groove width, and a steam channel traversing the bars and grooves of the refining zone, wherein the steam channel has a radially outer end radially inward of the outer peripheral edge of the plate and the steam channel has a width substantially greater than the groove width.