Air Knife Particulate Drying Plant
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Solution Overview
Problem
Existing plastic recycling plants face inefficiencies due to high water usage in washing and high energy costs in drying processes, particularly when using large quantities of hot air for drying particulate materials like granules or chads of plastic.
Innovation Solution
A plant design utilizing air knives with high-speed air flows between two facing surfaces to efficiently wash and dry particulate materials, where the air knives are oriented transversely to the material flow, allowing for effective water extraction and drying with reduced energy consumption by minimizing the need for heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional hot-air drying systems are used, then drying capacity is achieved, but energy consumption is high (150 kW)
Solution Approach 1:
The patent replaces the thermal field (hot air) with a mechanical field (high-speed air knife). Instead of using heated air to evaporate water, a high-speed jet of air at ambient temperature is used to mechanically remove water droplets from the material surface through shear stress and direct impact forces, thereby achieving drying with minimal energy input
Solution Approach 2:
The invention employs pneumatic principles by using compressed air to generate a high-speed jet (air knife) that flows across the material surface. The pneumatic system delivers a focused, high-velocity air stream that physically strips water from the material, replacing the conventional thermal drying process
2Productivity
If large quantities of hot air are used for drying, then drying efficiency is improved, but power consumption increases to 150 kW
Solution Approach 1:
The air knife system concentrates the drying action locally at the material surface through a high-speed, focused air jet. Instead of heating large volumes of air, the energy is concentrated in a narrow stream that directly contacts the material surface, creating intense local shear forces that efficiently remove water droplets without requiring system-wide heating
Solution Approach 2:
The invention changes the fundamental parameter of the drying medium from temperature (hot air) to velocity (high-speed air jet). By increasing the air velocity to supersonic or near-supersonic speeds, the kinetic energy of the air stream becomes sufficient to mechanically remove water, eliminating the need for thermal energy input
3Ease of operation
If conventional washing and drying processes are used, then material is processed, but water consumption and energy costs are high
Solution Approach 1:
The patent merges the washing and drying operations into a single integrated process. The high-speed air knife serves dual functions: it removes excess water from the material surface (drying) and can simultaneously contribute to washing by dislodging contaminants. This eliminates the need for separate washing and drying stages, reducing both water and energy consumption
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 significantly reduces energy consumption, achieving efficient drying with power levels around 40 kW per unit of material, compared to conventional hot air systems at 150 kW, while maintaining high efficiency and ensuring the material is thoroughly dry.
Implementation Method 1
emitting a high-speed air flow which passes through the layer of material so as to extract water from the material
Implementation Method 2
the air flow is conveyed through the layer of material so as to extract water from the material
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A plant (10, 110, 210) for treating particulate material comprises two facing surfaces (11, 12, 111, 112, 211, 212) which define an interspace (13, 113, 213) between them inside which a layer of particulate material is intended to be fed. At least one device (15, 115, 215) emits an air blade through at least one of the two surfaces and movement means (17, 117, 213) are provided for performing a relative movement, in a direction transverse to the extension of the air blade, of the layer of particulate material with respect to the air blade emission device (15, 115, 215). As a result it is possible to facilitate extraction with the air flow, through at least one of the two surfaces, of water which may be present in the material. The two surfaces may be or comprise two perforated conveyor belts (19, 20). A device (21) for emitting water, which is advantageously atomized, may also be arranged upstream of the air blade device (15, 115, 215).