Wood Chip Surface Flaming for Fuel Flowability
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Solution Overview
Problem
Wood chips with protruding fibers and sharp edges impede flowability and entanglement, limiting their use as a substitute fuel for wood pellets in heating devices due to impaired sliding properties.
Innovation Solution
Scarifying the surface of wood chips to achieve a smooth surface, followed by passing them through a rotary kiln to burn off fibers and edges, ensuring uniform flame exposure and subsequent abrasion for cleaning, while maintaining the calorific value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wood chips are used as a substitute fuel for wood pellets, then the effort associated with production is reduced, but the flowability and sliding properties are significantly impaired due to protruding fibers and sharp edges
Solution Approach 1:
The wood chips undergo preliminary surface treatment (scarfing) before being fed into the heating device. This preliminary action removes protruding fibers and sharp edges in advance, preventing entanglement issues during conveyance and metering operations, thus resolving the contradiction between ease of manufacture and ease of operation
Solution Approach 2:
The scarfed surface, which initially removes material from the wood chips, is converted into a benefit by improving flowability and reducing entanglement. The removal of surface imperfections transforms a potential waste issue into a functional improvement that enables reliable use in pellet-fed heating devices
2Ease of operation
If the particle size of wood chips is limited to a certain size range, then flow properties become comparable to wood pellets, but the use of wood chips as a substitute fuel is limited to a limited extent
Solution Approach 1:
Instead of uniformly restricting all wood chips to a narrow size range, the invention applies surface scarfing locally to the particle surface while allowing greater size variation. This local treatment of the surface quality enables broader particle size acceptance while maintaining good flow properties, thus increasing adaptability without sacrificing operational performance
3Ease of operation
If the surface of wood chips is scarfed to remove protruding fibers, then flowability is improved, but the calorific value may be reduced due to material removal
Solution Approach 1:
The scarfing process is applied partially rather than completely removing all surface material. By using controlled, moderate scarfing action that removes only the problematic protruding fibers and sharp edges while preserving the bulk of the wood chip material, the invention achieves improved flowability with minimal impact on calorific value
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 process enhances the flowability and metering properties of wood chips, making them comparable to wood pellets for use in heating devices, while also improving storage stability by reducing moisture absorption and eliminating pests and fungal infestation.
Implementation Method 1
fibers protruding from the wood chips are burned off by flaming the surface
Implementation Method 2
the steam emerging from the particle surface when exposed to flame counteracts the surface from being scorched
Implementation Method 3
This is advantageous if the passage through the rotary kiln is used to dry the wood chips
Implementation Method 4
subsequently cleaned of the burned-off fiber and chip residues by abrasion and rounded off in the area of singed, sharp edges, due to the friction between the individual ones Chip particles and on the other hand between the chip particles and the drum of the rotary kiln
Implementation Method 5
surface flaming involves making the particles hydrophobic
Data Source
AI summary
A substitute fuel for wood pellets made from dried wood chips with a particle size between 2 and 30 mm is described. To improve flowability, it is suggested that the wood chips have a flamed surface.