Sheet Drying Heat Recovery Segmentation
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Solution Overview
Problem
The energy consumption in drying sheet materials like plasterboard remains high due to the inefficiencies in current drying methods, particularly in secondary energy usage despite efforts to reduce primary energy needs.
Innovation Solution
The method employs low drying temperatures combined with multiple warm drying zones, utilizing heat recovery through scrubbers and air/liquid heat exchangers, and impinging jet nozzles to minimize energy consumption by recycling heat from exhaust drying medium without additional heating sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If heat from exhaust drying air is recovered and used for pre-heating drying air in the second stage, then primary energy consumption is reduced, but secondary energy consumption increases due to high mass flow requirements
Solution Approach 1:
The drying system is divided into multiple independent drying stages (first drying stage, second drying stage, third drying stage) with separate air circulation loops. Each stage has its own drying air flow path, allowing heat recovery from the first stage to be used in the second stage without requiring high mass flow rates. This segmentation enables efficient heat recovery while maintaining low secondary energy consumption.
2Use of energy by moving object
If relatively low drying temperatures are used, then primary energy consumption is reduced, but secondary energy consumption increases
Solution Approach 1:
The system maintains continuous drying action across multiple stages with heat recovery from the first stage continuously pre-heating the air in the second stage. The third stage continues this pattern by recovering heat from the second stage. This continuous heat recovery and utilization ensures that low drying temperatures are maintained throughout all stages without increasing secondary energy consumption, as the recovered heat continuously compensates for the lower temperature differential.
3Productivity
If a plurality of warm drying zones is used, then drying efficiency is improved, but device complexity increases
Solution Approach 1:
The heat recovery system serves multiple functions: it pre-heats drying air in subsequent stages, reduces primary energy consumption, and maintains appropriate temperature gradients across different drying zones. The same basic heat recovery mechanism is applied in both the second stage (recovering from first stage) and the third stage (recovering from second stage), providing a universal solution that improves drying efficiency without proportionally increasing system complexity.
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 significantly reduces primary energy consumption while controlling secondary energy usage, achieving considerable savings in drying costs by efficiently utilizing recovered heat across multiple warm zones.
Implementation Method 1
heat from the exhaust drying air from the first stage is recovered and used for pre-heating the drying air in the second stage
Implementation Method 2
using scrubbers and/or air/liquid heat exchangers for heat recovery
Data Source
Figure 1
Figure 2
AI summary
Provided herein is a method for drying sheet materials, comprising (i) advancing sheets to be dried along a path; (ii) heating a first drying medium (5) to a temperature above 140°C via first heating means (6), and directing the heated first drying medium to said sheets in a hot drying zone (3); and (iii) recovering heat from exhaust drying medium (7) of said hot drying zone (3) via a series of two or more heat recovery means (9a, 9b) and using the recovered heat for heating a second drying medium to a temperature below the temperature of said first drying medium without additional heating means, and directing the heated second drying medium to said sheets in a plurality of warm drying zones (4) downstream of said hot drying zone (3), wherein the cooled exhaust drying medium from upstream heat recovery means (9a) is passed over downstream recovery means (9b) and for each of said two or more heat recovery means (9a, 9b), the recovered heat is directed to one or more warm drying zones (4) associated with that heat recovery means (9a, 9b). Further provided herein is an arrangement for carrying out the present method.