PV Module Recycling Separation Using Hydrocyclone and Flotation
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Solution Overview
Problem
Existing recycling methods for photovoltaic modules produce poorly purified materials with high environmental and energy impacts, failing to effectively separate polymeric fractions from high-value metal and inorganic fractions, and require additional cleaning treatments.
Innovation Solution
A mechanical separation method involving a sedimentation tank with a stirring system and a flotation tank with air flow, allowing for the separation of solid metal and inorganic materials from organic-polymeric materials based on specific weight differences, followed by drying steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If pyrolysis heat treatment is used to remove polymeric material, then polymeric material can be removed, but environmental and energy impact increases and sustainability is compromised
Solution Approach 1:
The patent replaces the thermal pyrolysis system with a mechanical separation system consisting of a shredding unit, hydrocyclone separator, and flotation tank. The shredding unit mechanically breaks down photovoltaic modules into granular mixture, the hydrocyclone separator uses centrifugal force to separate materials by density, and the flotation tank uses air bubbles to separate polymeric material from metal fragments, eliminating the need for high-temperature heat treatment and its associated environmental and energy impacts.
Solution Approach 2:
The patent employs pneumatic and hydraulic mechanisms in the flotation tank where pressurized air is introduced to create bubbles that attach to metal fragments, causing them to float to the surface. The hydrocyclone separator uses water flow and centrifugal force to separate materials based on density differences. These pneumatic and hydraulic systems provide an environmentally friendly alternative to thermal processing.
2Manufacturing precision
If flotation system with kerosene collector is used to separate metal and silicon, then metal fraction can be separated, but complete sustainability is not guaranteed and additional cleaning treatments are required
Solution Approach 1:
The patent extracts and removes the harmful kerosene collector substance from the separation process entirely. Instead of using chemical additives, the invention relies on physical separation mechanisms: the hydrocyclone separator extracts materials based on density differences using water and centrifugal force, and the flotation tank uses clean air bubbles without any chemical collectors. This extraction of harmful substances eliminates the need for additional cleaning treatments of recovered materials.
Solution Approach 2:
The patent uses water as a disposable, environmentally benign fluid in the hydrocyclone separator and flotation tank, replacing the expensive and harmful kerosene collector. Water can be easily disposed of or recycled without environmental concern, and no additional cleaning of recovered materials is needed, making the process more sustainable and cost-effective.
3Manufacturing precision
If double flotation system with salt solution is used to separate EVA and PET, then specific weight-based separation is achieved, but the process depends heavily on external environmental conditions and requires complex liquid management
Solution Approach 1:
The patent segments the separation process into two distinct stages: first, the hydrocyclone separator performs a rough separation based on density differences, dividing the granular mixture into different streams; second, the flotation tank performs a more precise separation of polymeric material from metal fragments. This segmentation allows each unit to be optimized for its specific function, reducing overall system complexity compared to a single complex flotation system requiring precise salt solution density control.
Solution Approach 2:
The patent changes the separation parameter from density-based (hydrocyclone) to buoyancy-based (flotation with air bubbles). This parameter change simplifies the system by eliminating the need for precise salt solution concentration control and makes the process less sensitive to external environmental conditions such as temperature variations that would affect solution density.
4Quantity of substance
If mechanical shredding and screening operations are performed before flotation, then material preparation is achieved, but energy consumption increases and process complexity increases
Solution Approach 1:
The patent merges the shredding and separation operations into an integrated process flow. The shredding unit produces a granular mixture that is directly fed into the hydrocyclone separator, which in turn feeds the flotation tank. This merging of operations eliminates the need for separate screening steps and intermediate handling, reducing overall energy consumption and process complexity while maintaining effective material preparation for separation.
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
Achieves a clear separation of materials with low energy and environmental impact, reducing waste and eliminating the need for polluting additives or additional cleaning treatments.
Implementation Method 1
a) introducing the granular mixture into a hydrocyclone separator, so as to separate the granular mixture into different streams, on the basis of density differences
Implementation Method 2
separate the granular mixture into different streams, on the basis of density differences
Implementation Method 3
b) introducing the separated streams into a flotation tank, in which, by means of air bubbles, the polymeric material is brought to the surface, so as to separate the polymeric material from the metal fragments
Implementation Method 4
c) introducing the fractions obtained into a drying unit, so as to remove the moisture
Data Source
Figure 1~2
Figure 3~5
AI summary
Method for separating solid metal and/or inorganic material from organic-polymeric material deriving from the recycling treatment of at least one photovoltaic module (11), comprising at least a first step of obtaining a granular mixture formed by said solid metal and/or inorganic material and said organic-polymeric material deriving from the recycling treatment of at least one photovoltaic module (11), and at least a second step of introducing said granular mixture inside a sedimentation tank (18) provided with a stirring system (19) so as to carry out at least a first separation of recovery materials (R1) which are extracted from the sedimentation tank (18).