Solvent Recovery Discharge Device for Cellulosic Nonwoven Production
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Solution Overview
Problem
The production of cellulosic spunbonded nonwovens faces challenges with solvent loss and equipment corrosion during start-up, shutdown, and operational issues, particularly due to the flammability of spinning dopes and turbulence in air, which leads to safety, economic, and environmental concerns.
Innovation Solution
A plant and method that include discharge devices between the coagulation liquid delivery and collection systems, allowing for the removal and recycling of solvent-laden spunbonded nonwovens during start-up, shutdown, or operational problems, and feeding them back into the production process, preventing solvent contact with hot equipment and enabling solvent and cellulose recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spinning dope filaments are deposited during start-up, shutdown, or operational problems, then continuous production is maintained, but solvent loss and equipment corrosion occur
Solution Approach 1:
The patent extracts the harmful solvent-laden nonwoven material from the production process at specific discharge locations before it can cause solvent loss or equipment corrosion. Discharge devices are positioned between the coagulation liquid delivery device and the collecting device to remove problematic material during start-up, shutdown, or operational issues.
Solution Approach 2:
The patent introduces an intermediary discharge device system that mediates between the spinning system and the collecting device. This intermediary system allows selective removal of solvent-laden material while permitting normal production to continue, thus protecting downstream equipment without stopping the spinning process.
2Reliability
If carrier web is used during start-up to protect conveying device, then equipment protection is achieved, but additional material handling steps are required
Solution Approach 1:
The patent enables the system to protect itself automatically during start-up and shutdown by discharging solvent-laden nonwoven material through discharge devices. The system self-regulates by routing problematic material to discharge locations without requiring external carrier webs or manual intervention, thus simplifying the overall process.
3Loss of substance
If solvent-laden nonwoven is discharged and recycled, then solvent loss is minimized, but additional processing steps are required
Solution Approach 1:
The patent implements a discard and recover system where solvent-laden nonwoven material is discharged at specific locations and then recycled back to the spinning dope production. This closes the solvent loop, minimizing loss while integrating the recycling process into the existing production flow.
Solution Approach 2:
The patent establishes a feedback loop where discharged solvent-laden material is returned to the spinning dope production system. This feedback mechanism allows the system to reuse solvents and maintain production continuity, with the discharged material serving as input for subsequent processing cycles.
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 minimizes solvent loss, protects downstream equipment, and ensures operational reliability by recycling solvents and cellulose, reducing the risk of fire and corrosion, and allowing continuous spinning dope production with minimal downtime.
Implementation Method 1
the filaments are additionally contacted with a coagulant prior to the deposition of the nonwoven in order to regenerate the cellulose and to produce dimensionally stable filaments
Data Source
AI summary
A plant (1) for the production of spunbonded nonwoven (8), comprising a spinning solution production (3), a spinning system (2), a device (6) for the delivery of coagulation liquid, at least one conveying device (7, 9) for depositing the spunbonded nonwoven (8), and a collecting device (13) for the spunbonded nonwoven (8), wherein at least one discharge device (14) is provided between the device (6) for the delivery of coagulation liquid and the collecting device (13) for the spunbonded nonwoven (8).