Rotary Drum Dryer Recycle Crushing for Inline Pellet Size Control
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Solution Overview
Problem
Wet biosolids particles become oversized during recycling, leading to dryer shutdowns due to inability to separate them from the moist air and pellet stream, necessitating a solution to resize and control particle size effectively.
Innovation Solution
Implementing a system that includes a screen to select oversized pellets and a crusher inline with the recycle stream to resize them, producing a controlled size dried seed material recycling stream, which is then mixed with incoming wet granular biosolids to form a wet coated seed material stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If particles are recycled back to the dryer, then processing efficiency is improved, but particle diameter increases causing dryer shutdown
Solution Approach 1:
The patent extracts oversized particles from the recycle stream using a screen before recycling, removing the harmful element (oversized particles) that causes dryer shutdown while maintaining the beneficial recycle process
Solution Approach 2:
The patent changes the particle size parameter by crushing oversized particles back to the desired size range, allowing them to be recycled without causing dryer shutdown
2Loss of substance
If particles are recycled multiple times, then material utilization is improved, but particle size becomes too large for separation
Solution Approach 1:
The patent applies preliminary action by crushing oversized particles before they can accumulate to problematic sizes, maintaining particle size within acceptable ranges for continuous recycling
Solution Approach 2:
The patent implements feedback control where screens and crushers continuously monitor and adjust particle size in the recycle stream, ensuring particles remain within the optimal size range for separation and processing
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
Effectively prevents dryer shutdowns by maintaining optimal particle size, ensuring continuous operation and efficient processing of wet biosolids.
Implementation Method 1
Oversized pellets may be selected using a screen
Implementation Method 2
resizing oversized pellets from the recycle portion of the uncontrolled size dried pellet stream to produce the controlled size dried seed material recycling stream
Implementation Method 3
mixing the controlled size dried seed material recycling stream with the incoming wet granular biosolids stream to produce the wet coated seed material stream
Implementation Method 4
drying a wet coated seed material stream to produce a moist air and pellet stream
Data Source
AI summary
Apparatus and associated methods relate to drying a wet coated seed material stream comprising an incoming wet granular biosolids stream mixed with a controlled size dried seed material recycling stream to produce a moist air and pellet stream, separating an uncontrolled size dried pellet stream from the moist air and pellet stream, diverting a recycle portion of the uncontrolled size dried pellet stream to be recycled, diverting the remainder of the uncontrolled size dried pellet stream to an outlet, resizing oversized pellets from the recycle portion of the uncontrolled size dried pellet stream to produce the controlled size dried seed material recycling stream, and mixing the controlled size dried seed material recycling stream with the incoming wet granular biosolids stream to produce the wet coated seed material stream. Oversized pellets may be selected using a screen. The oversized pellets may be resized using a crusher inline with the recycle stream.