Bulk Solid Drying with Reversing Sweep Gas Flow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing dryers for bulk solids like soybeans and sunflower seeds are inefficient due to high air temperatures causing material degradation and significant heat loss, and require large quantities of air to remove moisture, leading to inefficiencies in heating and control of drying temperatures.
Innovation Solution
A dryer apparatus with spaced heat transfer plates and a sweep gas delivery system that reverses the flow of sweep gas direction to improve mass flow profile and residence time, reducing air requirements and heat loss while maintaining efficient drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot air is used for drying bulk solids, then drying efficiency is improved, but material degradation occurs due to high temperatures
Solution Approach 1:
The drying system is segmented into multiple heat transfer plates with spaced apart configurations, creating multiple heating zones. This allows different sections of bulk solids to be dried at different temperature levels, improving overall drying efficiency while preventing localized overheating and material degradation.
Solution Approach 2:
The patent applies local quality by directing sweep gas to specific regions between heat transfer plates where moisture accumulation occurs. This localized gas flow removes moisture from critical areas without requiring high temperatures across the entire drying chamber, thus maintaining material quality while achieving effective drying.
2Productivity
If high air temperature is used, then drying efficiency is improved, but heat loss increases when air is vented
Solution Approach 1:
The system recovers heat by using sweep gas to remove moisture from between heat transfer plates. The sweep gas, after absorbing moisture, can be heated and reused in subsequent drying cycles, recovering thermal energy that would otherwise be lost with vented air and reducing overall heat loss.
Solution Approach 2:
The patent implements continuous drying action through multiple heat transfer plates arranged in sequence, ensuring that bulk solids continuously receive heating treatment. This continuous process maintains efficient drying rates without requiring periodic high-temperature bursts that would increase heat loss.
3Productivity
If steam-filled tubes or heated plates are used, then drying efficiency is improved, but large quantities of air are required to remove moisture
Solution Approach 1:
The patent introduces sweep gas as an intermediary substance between the heated bulk solids and the main drying air. The sweep gas locally removes moisture from between heat transfer plates, reducing the burden on the main drying air system and decreasing the total quantity of air required for effective moisture removal.
4Quantity of substance
If large quantities of air are used to remove moisture, then moisture removal is improved, but heating efficiency decreases
Solution Approach 1:
The system extracts moisture removal function from the main drying air stream by introducing separate sweep gas flow between heat transfer plates. This extraction allows the main drying air to be used more efficiently for bulk heating, while the sweep gas handles localized moisture removal, improving overall heating efficiency.
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 solution enhances drying efficiency by minimizing air usage, controlling residence time, and preventing material degradation, resulting in improved temperature control and reduced energy loss during the drying process.
Implementation Method 1
A plurality of spaced apart heat transfer plates are disposed in the housing between the inlet and the outlet for passage of the bulk solids that flow from the inlet, through spaces between the heat transfer plates
Implementation Method 2
Dryers utilizing steam-filled tubes or heated plates may be utilized but such dryers require a purge or sweep air to absorb water vapor and carry the water vapor out of the dryer
Data Source
AI summary
An apparatus for drying or conditioning bulk solids, includes a housing including an inlet for receiving the bulk solids, and an outlet for discharging the bulk solids, a plurality of spaced apart heat transfer plates assemblies disposed in the housing between the inlet and the outlet for passage of the bulk solids that flow from the inlet, through spaces between the heat transfer plates, and a sweep gas delivery system for the flow of sweep gas in a first direction across the direction of flow of the bulk solids. The sweep gas delivery system includes at least one valve for reversing the flow of the sweep gas from the first direction to a second direction, opposite to the first direction.