Agglomerated Lignin Dust Explosion Prevention via Controlled Moisture

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Solution Overview

Problem

The handling of lignin with minimal moisture content leads to dust clouds, increasing the risk of dust explosions due to the formation of fine particles during handling and processing.

Innovation Solution

A process involving roll compaction, milling, and sieving of lignin with controlled moisture content between 1 wt-% to 45 wt-%, using rolls with cavities and sieving screens to achieve a final particle size distribution where less than 10 wt-% of particles have a diameter below 100 μm, effectively reducing dust-forming fines and preventing explosions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If lignin is handled with minimal moisture content (0-5 wt-%), then the lignin is easier to process and transport, but dust clouds form during handling which increase the risk of dust explosions

Engineering Contradiction:
Improveease of handlingVSAvoiddust explosion risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention changes the moisture content parameter from minimal (0-5 wt-%) to a controlled range (10-45 wt-%), which fundamentally alters the physical state of lignin during handling. This parameter change reduces dust formation by maintaining lignin in a less friable state, thereby eliminating the dust explosion hazard while preserving ease of operation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies beforehand cushioning by pre-moistening the lignin to a controlled moisture content before handling and processing. This preparatory measure cushions against the formation of dust clouds during subsequent mechanical operations, preventing the harmful effect of dust explosions before they can occur

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Productivity

If lignin is compacted with low moisture content, then the compaction process is more efficient, but the resulting particles are more prone to forming dust clouds during subsequent handling

Engineering Contradiction:
Improvecompaction efficiencyVSAvoiddust cloud formation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention changes the moisture content parameter used in compaction from low (0-5 wt-%) to controlled (10-45 wt-%), which modifies the compaction mechanics and particle bonding characteristics. This results in denser, more cohesive particles that generate fewer dust clouds during subsequent handling, thus maintaining productivity while reducing harmful dust formation

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If lignin is dried to minimal moisture content for storage, then storage space is optimized and transport costs are reduced, but the lignin forms dust clouds during loading and unloading

Engineering Contradiction:
Improvestorage densityVSAvoiddust explosion risk during loading/unloading
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The invention changes the storage moisture content parameter from minimal (0-5 wt-%) to controlled (10-45 wt-%), which alters the physical properties of lignin during storage and handling operations. This results in reduced dust generation during loading and unloading while maintaining adequate storage density and transport efficiency

Inventive Principle:
Principle #35Parameter changes

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

The process significantly reduces the risk of dust explosions and allows for easier handling, transportation, and storage of lignin, while maintaining a controlled particle size distribution for use in chemical synthesis and binder production.

Implementation Method 1

a) compaction of lignin, wherein lignin having a moisture content of from 1 wt-% to 45 wt-% is agglomerated by means of roll compaction

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

c) a sieving step, wherein the product of step b) is subjected to sieving to remove particles having a particle diameter below 100 μm

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentUS12162900B2Process for producing agglomerated lignin and use thereof
Publication Date: 2024.12.10 STORA ENSO OYJ

AI summary

The present invention is directed to a process to produce agglomerated lignin with a controlled particle size distribution. The agglomerated lignin is essentially free of dust so that the risk of dust explosion is greatly reduced.