Underwater Pelletizing Polyamide Beads Die Hole Blocking
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Solution Overview
Problem
Existing methods for producing small-diameter polyamide beads, particularly for use as proppants in hydrocarbon extraction, face challenges with high melting point polymers due to die hole blocking issues in underwater pelletizing processes, limiting the production of beads smaller than 2 mm in diameter.
Innovation Solution
An underwater pelletizing method that rapidly establishes and maintains high pressure for feeding molten polyamide into die holes, using a gear pump and controlling temperature and throughput to produce spherical beads with diameters less than 1.7 mm, minimizing die hole blocking and enabling industrial-scale production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the underwater pelletizing process is used to produce polyamide beads, then spherical beads with good flowability are obtained, but die holes are blocked by solidified or crystallized polymer when producing small-diameter beads
Solution Approach 1:
The patent changes the physical parameters of the system by introducing a heating device that raises the temperature of the die holes. This temperature parameter change prevents the polyamide material from solidifying or crystallizing in the die holes, thereby resolving the blocking issue while maintaining the ability to produce small-diameter spherical beads through the underwater pelletizing process.
Solution Approach 2:
The heating device is activated before and during the pelletizing process to pre-heat the die holes. This preliminary action ensures that the polyamide material remains in a molten state as it passes through the die holes, preventing solidification and blocking before the beads are formed and extruded into the water.
2Productivity
If the die hole size is increased to prevent blocking, then productivity is maintained, but bead diameter becomes greater than 2 mm which is too large for certain applications
Solution Approach 1:
By changing the temperature parameter of the die holes through heating, the patent enables the use of smaller die hole diameters without causing blocking. This allows the production of beads with diameter less than 2 mm (specifically 0.5-1.5 mm) while maintaining high productivity, as the heated die holes prevent material solidification even in small openings.
Solution Approach 2:
The heating device applies a preliminary anti-action by counteracting the natural cooling and solidification tendency of the polyamide material in the die holes. This prevents the harmful effect of blocking before it can occur, enabling the use of small die hole sizes for producing small-diameter beads without sacrificing productivity.
3Strength
If polyamides with high melting point are used, then mechanical and chemical properties are improved, but the risk of solidification and crystallization in die holes increases
Solution Approach 1:
The patent addresses the high solidification risk of high melting point polyamides by changing the temperature parameter of the die holes through active heating. This compensates for the high melting point of the material, keeping it in a molten state during extrusion and preventing solidification and crystallization in the die holes, thereby enabling the use of these high-performance materials.
Solution Approach 2:
The patent converts the harmful effect of high melting point (which causes solidification risk) into a benefit by using the heating device to precisely control the temperature. The same high melting point property that causes blocking is leveraged to ensure complete melting and uniform flow through the heated die holes, producing high-quality small-diameter beads with superior mechanical and chemical properties.
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 method effectively produces polyamide beads with uniform, spherical shapes and improved mechanical and chemical properties, suitable for use as proppants in hydrocarbon extraction, by maintaining stable pressure and temperature conditions during the granulating process.
Implementation Method 1
rapidly establishes and maintains high pressure for feeding molten polyamide into die holes
Implementation Method 2
underwater pelletizing method...produce spherical beads
Implementation Method 3
die holes, the diameter of which is between 0.3 mm and 1.7 mm
Data Source
AI summary
Certain polyamide beads or granules are useful as a sustaining material for underground natural or artificial cracks of the earth's crust essentially employed for the extraction of hydrocarbons such as crude oil or natural gas; such polyamide beads have a spherical or ellipsoidal shape and have a surface free of concave portions, advantageously having a uniform shape, and having a mean diameter lower than or equal to 1.7 mm and a porosity lower than 0.1 ml/g, and are produced using a particular cutting device/extruder.