Single Refiner With Multiple Zones For Lignocellulose Fibre Refining
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Solution Overview
Problem
The existing refining processes for lignocellulose-containing fibre materials require multiple refiners to achieve high quality, as each fibre material fraction needs specific refining surface characteristics, leading to increased equipment costs and reduced pulp quality when mixing fractions with different qualities.
Innovation Solution
A single refiner with multiple refining zones, each optimized for specific fibre material fractions, allowing simultaneous refinement of different fibre material flows with tailored refining surface characteristics to achieve distinct refining effects for different layers or processes in paper or board production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple refiners are used to refine different fibre material fractions separately, then the pulp quality is improved, but the device complexity and equipment costs increase
Solution Approach 1:
The single refiner is divided into multiple refining zones along its length, with each zone having different refining surface characteristics (e.g., different blade configurations, gap sizes, or surface roughness) optimized for specific fibre material fractions. This allows simultaneous refinement of different fibre types (e.g., hardwood, softwood, recycled fibres) with different quality requirements within one refiner, maintaining high pulp quality while reducing the number of refiners needed
Solution Approach 2:
Different sections (zones) of the refiner are equipped with locally optimized refining surfaces tailored to specific fibre material fractions. For example, one zone may have coarse refining surfaces for recycled fibres while another zone has fine refining surfaces for virgin fibres. This local customization of refining characteristics enables each zone to process its designated fibre type optimally, achieving high pulp quality across all fractions without requiring separate refiners
2Device complexity
If a single refiner is used to refine mixed fibre material fractions, then the device complexity is reduced, but the pulp quality deteriorates due to compromise refining surface characteristics
Solution Approach 1:
The refiner is segmented into multiple zones along its axial length, with each zone dedicated to refining specific fibre material fractions. The segmentation allows each zone to have independently optimized refining surface characteristics (blade angle, gap, surface texture) matched to the specific requirements of each fibre type, preventing the quality compromise that would result from using a single uniform refining surface for all fibre types
Solution Approach 2:
Each refining zone within the single refiner is equipped with locally optimized surfaces tailored to specific fibre fractions. For instance, the first zone may be optimized for hardwood fibres requiring gentle refinement, while the second zone is optimized for softwood fibres requiring more intensive refinement. This local quality optimization ensures high pulp quality for each fibre fraction without requiring separate refiners
3Productivity
If fibre material fractions are mixed before refining, then the productivity is improved, but the manufacturing precision decreases due to uniform refining treatment
Solution Approach 1:
The refiner is divided into multiple zones that can process different fibre material fractions simultaneously and independently. Each zone maintains its own refining parameters (surface characteristics, gap, speed) optimized for the specific fibre type it processes. This segmentation allows mixed fibre material to be fed into the refiner while each fraction receives appropriate refining treatment in its designated zone, maintaining high manufacturing precision while improving productivity through simultaneous processing
Solution Approach 2:
Different zones of the refiner provide locally optimized refining conditions for different fibre fractions. For example, one zone may have finer blade spacing and smaller gaps for delicate fibres, while another zone has coarser settings for robust fibres. This local quality differentiation enables simultaneous refinement of mixed fibre materials with varying quality requirements, achieving both high productivity and manufacturing precision
Data Source
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Figure 3
AI summary
A refiner (1, 2, 3, 4) for refining lignocellulose-containing fibre material. The refiner comprises at least two substantially oppositely positioned refining elements (6, 6a, 6b, 9) each of them comprising at least one refining surface (8, 8a, 8b, 11, 11a, 11b) with blade bars (25, 27) and blade grooves (26, 28). The refining surfaces of two oppositely positioned refining elements face towards each other and form between them a refining chamber (15, 15a, 15b) receiving fibre material to be refined. The refiner further comprises at least two feed channels (19a, 19b) for feeding into the refiner at least one fibre material fraction (FM1, FM2) to be refined, at least two refining zones (21a, 21b) with at least one different refining surface characteristic between the refining zones (21a, 21b), each refining zone (21a, 21b) intended to refine one fibre material fraction (FM1, FM2) of the at least one fibre material fraction (FM1, FM2), and at least one discharge channel (23, 23a, 23b) for discharging out of the refiner at least one flow of refined material.