Silicon Purification Device With Inclined Flow Plates
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Solution Overview
Problem
Current silicon purification methods for solar cells are costly due to high energy consumption, silicon loss, and low mass transfer of impurities from liquid silicon to gas, limiting the efficiency and cost-effectiveness of the purification process.
Innovation Solution
A silicon purification device with inclined flow plates that have multiple changes of direction and a gas flow perpendicular to the liquid silicon flow, creating a vortex that enhances impurity transport, reducing device volume, energy consumption, and silicon loss while maintaining purification speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional purification processes (fluidized bed reactor, distillation) are used, then high-purity silicon is produced, but production costs are high due to investment, energy consumption, and waste reprocessing
Solution Approach 1:
The invention changes the physical parameters of the purification process by using a vertical downward flow configuration with specific velocity ranges (0.1-10 m/s) and temperature conditions (1400-1900°C), replacing conventional horizontal or fluidized bed configurations. This parameter optimization enables metallurgical-grade purification at lower costs while achieving solar-grade purity
Solution Approach 2:
The invention extracts and removes specific impurities (boron and phosphorus) from silicon through selective evaporation and mass transfer mechanisms. By focusing on removing these key contaminants through controlled gas flow and temperature gradients, the process achieves high purity without requiring multiple complex purification stages, thereby reducing overall production costs
2Manufacturing precision
If vacuum evaporation and gas blowing refining are used for phosphorus and boron removal, then purification is achieved, but the process is limited by mass transfer velocity in liquid phase, evaporation rate, and gas phase mass transfer
Solution Approach 1:
The invention introduces dynamic gas flow through the liquid silicon at controlled velocities (0.1-10 m/s), creating continuous motion and turbulence that enhances mass transfer. The gas flow dynamically interacts with the liquid phase, preventing stagnant zones and maintaining high purification velocity throughout the process
Solution Approach 2:
The invention uses gas flow (pneumatic action) passing through the liquid silicon to enhance impurity removal. The gas flow creates bubbles and turbulence that increase the interfacial area for mass transfer between liquid and gas phases, significantly accelerating phosphorus and boron removal rates beyond conventional static or slow-flow methods
3Manufacturing precision
If low thickness silicon flows under reduced pressure are used, then purification is enhanced, but the process becomes expensive and not commercially viable
Solution Approach 1:
The invention optimizes pressure parameters to operate at or near atmospheric conditions rather than requiring high vacuum systems. By adjusting temperature, gas flow velocity, and residence time parameters, the process achieves effective purification without the high capital and operational costs associated with maintained vacuum systems, enabling commercial viability
4Ease of operation
If conventional flow plate geometry is used, then device operation is simple, but mass transfer of impurities from liquid silicon to gas is low and silicon loss and energy consumption are high
Solution Approach 1:
The invention uses vertical flow plates with downward curvature that guide the liquid silicon flow in an arc rather than a straight line. This curved geometry increases the residence time of liquid silicon in the reaction zone, enhances gas-liquid contact area, and improves mass transfer efficiency without complicating the device structure or operation
Solution Approach 2:
The invention transitions from horizontal or flat flow plate configurations to vertical downward flow with three-dimensional curvature. This dimensional change creates a longer effective path length and increased surface area for mass transfer within a compact device volume, improving efficiency while maintaining operational simplicity
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 optimized geometry of the device achieves higher impurity transfer efficiency with lower gas and energy consumption, resulting in a more cost-effective and efficient purification process for producing high-purity silicon for solar cells.
Implementation Method 1
the friction of the gas has a positive effect because it induces a vortex in the liquid silicon and thus increases the transport of the impurities from the liquid silicon to the gas
Implementation Method 2
means for supplying on each flow plate a gas for evacuating silicon impurities
Data Source
Figure 1~2
Figure 3a~3b
Figure 3c~3d
AI summary
The invention is related to a silicon purification device, characterized in that it comprises: - means (15,3) for supplying liquid silicon, - at least one inclined flow plate (5) supplied with the liquid silicon, each flow plate (5) including a path for the liquid silicon flow, the path comprising several changes of direction, and - means (11,10) for supplying on each flow plate (5) a gas for evacuating silicon impurities counter to the liquid silicon flow.