Wheel Dryer Segmentation for Bulk Material Drying Energy Reduction
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Solution Overview
Problem
Existing methods for drying bulk goods in drying silos require complex designs and high energy consumption due to high flow resistances and inefficient energy use in regenerating and drying processes, particularly in wheel dryers.
Innovation Solution
The method involves parallel continuous drying and cooling phases with intermittent adsorbent heating, optimizing energy use by doubling the heating region compared to cooling, and using a wheel dryer with divided segments and a hollow shaft heat exchanger to minimize energy consumption and maintain dew point quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the exhaust air flow is dried in a wheel dryer with adsorbent and reintroduced to bulk goods, then the drying efficiency is improved, but the energy consumption and device complexity increase due to high flow resistances and complex regeneration requirements
Solution Approach 1:
The wheel dryer drum is divided into at least three wheel segments: a first region for drying/dehumidifying exhaust air, a second region for heating the adsorbent, and a third region for cooling the adsorbent. This segmentation allows simultaneous execution of drying and cooling operations while enabling efficient heat recovery from the heating region to preheat cooling air, significantly reducing overall energy consumption.
Solution Approach 2:
The invention combines multiple functions into the wheel dryer system: drying of exhaust air, cooling of adsorbent, heating of adsorbent for regeneration, and heat recovery. The cooling region uses a heat exchanger to preheat the cooling air using heat from the heating region, merging thermal energy recovery with the cooling process to minimize external energy input.
2Reliability
If the wheel dryer continuously dries and cools the adsorbent, then the drying quality is maintained, but the energy consumption increases due to continuous operation of both drying and cooling systems
Solution Approach 1:
The wheel dryer operates continuously with the drum rotating through all three regions (drying, heating, cooling) without interruption. The drying of exhaust air and cooling of adsorbent occur simultaneously and continuously in different regions of the same drum, maintaining constant drying quality while avoiding the energy waste of stopping and starting systems.
Solution Approach 2:
The drum rotation creates periodic exposure of the adsorbent to different functional regions. As the drum rotates, each section of the adsorbent bed periodically passes through the drying region, heating region, and cooling region, enabling continuous regeneration and cooling cycles that maintain drying effectiveness while optimizing energy utilization through heat recovery.
3Loss of energy
If the drum is stopped during cooling or regenerating phase, then energy consumption is reduced, but the productivity decreases due to intermittent operation
Solution Approach 1:
By segmenting the drum into three functional regions, the system enables simultaneous execution of drying, heating, and cooling operations. The drum continues rotating without stopping, maintaining continuous productivity while the integrated heat recovery system minimizes energy consumption by utilizing waste heat from the heating region to preheat cooling air.
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 approach reduces energy consumption by approximately 38% and allows for more economical operation of wheel dryers, maintaining quality standards while reducing operational costs and environmental impact.
Implementation Method 1
the exhaust air flow that is discharged from the drying silo or the returning air is dried in a drying cell, preferably a wheel dryer, that contains a drying or adsorbing agent
Implementation Method 2
the region of the second wheel segment is used for heating the adsorbent
Implementation Method 3
the regenerating phase with the adsorbent heating
Implementation Method 4
the region of the third wheel segment is used for cooling the adsorbent
Implementation Method 5
the drum of the wheel dryer is stopped in the cooling or regenerating phase and advanced to a selectable region, preferably the cooling region
Data Source
AI summary
The invention relates to a method for drying bulk goods, in particular solids, such as granular materials, powders, grains, films, shreds, or the like, preferably plastic granular material, in a drying silo (9) by means of an air flow. The exhaust air flow (5) that is discharged from the drying silo (9) is dried in a wheel dryer (1). The adsorbent is regenerated and cooled in the wheel dryer. A rotatable drum (2) of the wheel dryer (1) is divided into at least three wheel segments, wherein the region of a wheel segment is used for drying or dehumidifying the exhaust air flow, the region of the second wheel segment is used for heating the adsorbent, and the region of the third wheel segment is used for cooling the adsorbent. The drying or dehumidifying phase (14) for the exhaust air flow (5) and preferably the adsorbent cooling occur in parallel, in particular in a continuous manner during the operation. The regenerating phase (15) with the adsorbent heating is carried out at intervals during the operation. The drum (2) of the wheel dryer is stopped in the cooling (16) or regenerating phase (15) and advanced to a selectable region, preferably the cooling region, after the cooling (16) or regenerating phase (15) finishes.