Solvent Regeneration in Lyocell Spinning via Waste Comminution

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Solution Overview

Problem

The lyocell process for cellulose fibre production faces inefficiencies due to incomplete solvent regeneration and solvent loss, leading to high energy costs and low economic efficiency.

Innovation Solution

A process and device for regenerating cellulose solvents by collecting and recycling solvent-containing waste from various stages of the lyocell process, involving comminution and solvent extraction from shaped article waste, followed by concentration and purification to achieve high recovery rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If evaporation process is used to concentrate NMMO from liquid waste, then solvent regeneration is achieved, but energy consumption increases significantly

Engineering Contradiction:

Improvesolvent regenerationVSAvoidenergy consumption

Core Design Contradiction:

Loss of substanceVSUse of energy by moving object

Solution Approach 1:

The invention applies preliminary action by collecting and concentrating solvent-containing waste liquids from multiple process stages (spinning bath, washing, drying) before the final evaporation step. This pre-concentration reduces the volume requiring energy-intensive evaporation, thereby lowering overall energy consumption while maintaining effective solvent regeneration

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention merges multiple waste streams containing solvent (spinning bath waste, washing waste, drying waste) into a single concentrated stream for regeneration. By combining these streams and performing joint evaporation, the total energy required is reduced compared to treating each stream separately, resolving the contradiction between complete solvent recovery and energy consumption

Inventive Principle:

Principle #5Merging (Combining)

2Productivity

If traditional spinning process is used, then cellulose fibres are produced, but solvent loss occurs at multiple stations

Engineering Contradiction:

Improvecellulose fibre productionVSAvoidsolvent loss

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The invention implements feedback by establishing a closed-loop system where solvent-containing waste from all process stations (spinning, washing, drying) is collected, treated through evaporation, and the regenerated solvent is fed back into the spinning process. This continuous feedback loop minimizes solvent loss by ensuring it is recovered and reused rather than discarded

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The invention creates a universal solvent recovery system that handles all types of solvent-containing waste streams from different process stations through a single integrated evaporation and regeneration apparatus. This multi-functional approach ensures comprehensive solvent recovery across all production stages while maintaining productivity

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 improves the economic and ecological efficiency of cellulose fibre production by achieving high solvent recovery rates, reducing energy consumption, and minimizing solvent loss.

Implementation Method 1

a comminutor for consolidated shaped cellulose articles

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

extracting the solvent from the comminuted shaped article waste

Methodology Applied

Scientific EffectSolvation: Solvation

Data Source

PatentUS20220220640A1Method and device for regenerating a solvent of cellulose from a spinning process

Publication Date: 2022.07.14 AUROTECH GMBH

AI summary

A process and a device for regenerating a solvent for cellulose in a shaped cellulose article production process, including the steps of starting a continuous process for the production of solid shaped cellulose articles from a cellulose solution which includes the steps of: i) providing a cellulose solution of dissolved cellulose and a cellulose solvent and preferably a non-solvent, particularly preferably water, ii) shaping the cellulose solution into a desired geometrical shape, iii) consolidating the shaped cellulose solution into shaped cellulose articles in a coagulation liquid, iv) washing the shaped cellulose articles, wherein upon start-up and/or during the continuous process, shaped article waste of the cellulose solution accrues in an unwanted form, collecting the shaped article waste in the unwanted form, comminuting the shaped article waste, extracting solvent from the comminuted shaped article waste.