Solvent Film Casting Closed-Loop Gas Recycling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing solvent-based films require energy-intensive treatment of dried air to remove residual solvents, leading to emissions and increased costs, despite solvent recovery efforts.
Innovation Solution
Implementing a closed circuit system where dried gas mixture is recycled back into the process by feeding it into the casting area, utilizing cryocondensation for high solvent separation and inerting with nitrogen to prevent emissions, and using multiple dryer zones for efficient drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If dried air is released into the environment after solvent recovery, then solvent can be recovered and recycled, but energy-intensive treatment is required to remove residual solvents and emissions occur
Solution Approach 1:
The dried air is continuously recirculated back into the casting area instead of being released, creating a continuous closed-loop system where the drying medium performs useful work repeatedly, eliminating the need for energy-intensive exhaust air treatment while maintaining solvent recovery
Solution Approach 2:
Instead of discarding the dried air containing residual solvents into the environment, the system recovers and reusesthe dried air in the drying process, transforming what would be waste into a valuable resource and eliminating emissions entirely
2Productivity
If fresh air is used for drying, then drying efficiency is maintained, but solvent emissions increase and environmental impact worsens
Solution Approach 1:
The system implements feedback by continuously monitoring and recirculating the dried air back into the casting area, creating a self-regulating closed-loop system that maintains drying efficiency while preventing solvent emissions through complete feedback utilization of the drying medium
3Object-affected harmful factors
If activated carbon filtration is used to treat exhaust air, then residual solvents are reduced, but treatment costs and energy consumption increase
Solution Approach 1:
The system converts what would be harmful emissions into a beneficial resource by recirculating the dried air containing residual solvents back into the process, transforming a waste stream into a valuable drying medium and eliminating the need for energy-intensive filtration systems
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 eliminates solvent emissions and reduces energy consumption by recycling dried air, allowing for a more energetically favorable production process with minimal environmental impact.
Implementation Method 1
In order to achieve a particularly high degree of drying of the gas mixture and to achieve a very high level of solvent separation, the gas mixture can be dried in step f) by means of a cryocondensation process. Here, the gas mixture is cooled below the dew point of the solvent contained in the gas mixture.
Implementation Method 2
During the drying process, the solvent evaporates both in the casting area and in the downstream stretching device and roller dryer.
Data Source
Figure 1
AI summary
The invention relates to a method and a device (1) for producing a film (7) or a foil. The device has at least one casting region (2) which is at least partly housed and in which at least one continuous belt (4) and at least one casting device (3) for applying a material (8) onto the continuous belt (4) are arranged. The casting region (2) is further equipped with at least one removal device (5) for separating the material (8) from the continuous belt (4). At least one stretching device (9) which is at least partly housed is arranged downstream of the casting region (2) when seen in the transport direction of the material (8), said stretching device having clamping elements for clamping the material (8) separated from the continuous belt (4), and at least one dryer (10) which is at least partly housed and comprises rollers (6) for guiding the material (8) in a meandering manner is arranged downstream of the at least one stretching device (9). The device (1) has at least one cooling device (15) for obtaining solvent from a gas mixture, said cooling device (15) having at least one inlet opening (16) for supplying a gas mixture, from which the solvent is to be separated, and at least one outlet opening (17) for discharging a gas mixture, from which at least one part of the solvent has been separated, from the cooling device (15) in order to obtain the solvent. The at least one inlet opening (16) is connected to an interior of the casting region (2) and/or an interior of the stretching device (9) and/or an interior of the at least one dryer (10), and the at least one outlet opening (17) of the cooling device (15) is connected to the interior of the at least one dryer (10) via at least one line (18).