Bulk Material Drying System with Fresh Air Dilution
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Solution Overview
Problem
Conventional drying systems for agricultural grains face inefficiencies in energy use and risk of fires due to dust ignition from recirculating humid exhaust air, which is not adequately heated and humidified, leading to suboptimal drying conditions and safety concerns.
Innovation Solution
The system introduces fresh air into the drying zones to improve the humidity and temperature of recirculated exhaust air, using separate air heaters to control the temperature of the air mixture, and incorporates air recirculation and additional fresh air to enhance energy efficiency and reduce dust levels, allowing for higher operating temperatures without energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If exhaust air from the first part of drying zones is recirculated as supply air to the second part, then energy efficiency is improved, but the risk of fire due to dust ignition increases
Solution Approach 1:
The patent extracts the harmful dust component from the recirculated exhaust air by introducing fresh air as a diluting medium. The fresh air inlet (44) and air mixer (48) separate the dust-laden exhaust air from the clean fresh air, allowing the exhaust air to be returned to the drying zones while the fresh air suppresses dust concentration to prevent ignition.
Solution Approach 2:
Fresh air acts as an intermediary substance between the dust-laden exhaust air and the drying zones. It mediates by diluting the exhaust air in the air mixer, reducing dust concentration to safe levels while maintaining the energy-efficient recirculation of moisture-laden air for further drying.
2Object-affected harmful factors
If fresh air is introduced to dilute exhaust air, then fire risk is reduced, but energy efficiency decreases due to introducing unheated air
Solution Approach 1:
The fresh air is pre-heated in the fresh air heater (50) before being mixed with the exhaust air. This preliminary heating action ensures that the diluting air does not cool the recirculated air mixture significantly, maintaining energy efficiency while still achieving dust dilution and fire risk reduction.
3Loss of energy
If recirculated exhaust air is used without additional fresh air, then energy efficiency is maximized, but drying effectiveness decreases due to insufficient humidity control
Solution Approach 1:
The patent changes the humidity parameter of the supply air to the second part of drying zones by mixing recirculated exhaust air (high humidity) with fresh air (lower humidity). This parameter adjustment optimizes the humidity level for effective drying in the second drying section, preventing over-humidification while maintaining energy efficiency.
4Manufacturing precision
If multiple separate air heaters are used for different air streams, then temperature control precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the air heating function into two independent heating units: an exhaust air heater (38) for heating recirculated exhaust air and a fresh air heater (50) for heating incoming fresh air. This segmentation allows independent temperature control of each air stream, achieving precise temperature management while maintaining system simplicity through modular design.
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 increases energy efficiency, reduces the risk of fires, and enables higher throughput by maintaining higher temperatures in the drying zones, while returning dust-laden air to the material for further drying, thus improving the overall drying process and energy yield.
Implementation Method 1
an air heater (38) for heating the recirculated exhaust air from the first part of the drying zones
Implementation Method 2
The product or bulk material heats up and releases its moisture to the warm air passing by
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The drying unit (10) has drying zones (T1-T16) which are provided for drying the bulk material (20). An air duct is used for passage of air through drying zones. A lower air preluder (22) is used for introducing fresh air (24) from the vicinity of drying unit as supply air in a primary portion (26) of drying zones. An air forwarder (32) is used for passing air (30) from the primary portion into secondary portion (36) of drying zones. An upper air preluder (44) is used for introducing additional fresh air (46) from the vicinity of drying unit into secondary portion of drying zones. An independent claim is included for method for operating drying unit.