Two-Step Granule Size Reduction Preventing Equipment Blockages
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Solution Overview
Problem
Existing methods for reducing granular chemical particle size, such as EP 2 586 849, face challenges with granules settling quickly and blocking equipment, making large-scale production difficult and unsafe, and require extensive experimentation for parameter adjustment.
Innovation Solution
A two-step process using a high-speed disperser with a mixing disk followed by a rotor stator mixer, with optional thickeners and dispersing agents, to maintain homogeneity and prevent blockages, allowing for tailored parameter settings and efficient size reduction across various materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only a rotor stator system is used for particle size reduction, then the process is simplified to a single step operation, but the granules settle quickly and block the equipment making continuous operation difficult
Solution Approach 1:
The particle size reduction process is divided into two distinct steps: first using a high-speed disperser with mixing disk to perform initial size reduction and prevent settling, then using a rotor stator mixer for final size reduction. This segmentation allows each device to perform its optimal function without the other's drawbacks.
Solution Approach 2:
The high-speed disperser performs preliminary particle size reduction and creates a homogenous suspension before the material enters the rotor stator mixer. This preliminary action prevents granules from settling and blocking the rotor stator system during the main size reduction process.
2Productivity
If a rotor stator mixer is used with high feed rate of granules, then productivity increases, but the granules create high concentration at the bottom and block the mixer
Solution Approach 1:
The high-speed disperser performs preliminary size reduction and creates a homogenous suspension before material enters the rotor stator mixer, allowing high feed rates without blockages.
Solution Approach 2:
The high-speed disperser acts as an intermediary device between material feeding and the rotor stator mixer, preparing the material in a form that can be safely and continuously processed at high rates.
3Device complexity
If granules are added to liquid medium without preliminary dispersion, then the process is simpler, but the granules settle immediately creating non-homogenous feed to the mixer
Solution Approach 1:
The mixing process is segmented into two functional stages: initial dispersion by high-speed disperser to ensure homogeneity, followed by size reduction by rotor stator mixer. This segmentation maintains stable composition throughout the process.
Solution Approach 2:
The high-speed disperser performs preliminary dispersion to create a homogenous suspension before the rotor stator mixer processes the material, ensuring stable composition throughout the size reduction process.
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 process ensures a stable, homogenous mixture, preventing equipment blockages and enabling efficient size reduction with high specific surface area and measurable particle distribution, suitable for large-scale production and quality control.
Implementation Method 1
a high speed disperser having a mixing disk
Implementation Method 2
a rotor stator mixer
Implementation Method 3
adding a thickener to set the viscosity of the aqueous system between 100 cps and 200 cps
Implementation Method 4
providing to said mixing vessel (1) water, (2) a defoamer
Data Source
AI summary
This invention provides a process for reducing the average particle size of a granular material by a factor of at least 20 by: - providing a mixing vessel equipped with (A) a high speed disperser and (B) a rotor stator mixer, - providing a liquid medium to the mixing vessel, - switching on the high speed disperser (A) at a speed ranging from 1 to 50 m/s, - adding to the mixing vessel a granular material having an average particle size ranging from 1 to 5 mm, - operating the high speed disperser (A) for a period of time sufficient to reduce the average size of the granular material by a factor of at least about 10, thus producing granules of an intermediate average size ranging from 0.1 to 0.5 mm, and - switching on the rotor stator mixer (B) and operating it for a period of time sufficient to reduce the average size of the intermediate granules by a factor of at least about 2.