Lignin Separation via Solvent Fractionation
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Solution Overview
Problem
Current methods for producing lignin are limited by inefficiencies in isolating lignin in sufficient purity, leading to reduced commercial applications due to environmental concerns and lack of available supplies, with existing processes either polluting or modifying lignin, making it unsuitable for reactive uses.
Innovation Solution
A solvent-based fractionation process using aliphatic alcohols, water, and sulfur dioxide to dissolve and separate lignocellulosic material into cellulose, hemicelluloses, and lignin, where lignin is precipitated by reheating the liquor at low pH, resulting in a pure, reactive lignin product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sulfite pulping is used to produce lignin, then lignin can be isolated, but the process causes significant pollution by discharging dissolved wood sugars and lignin to rivers and streams
Solution Approach 1:
The invention extracts and recovers lignin and sugars from the pulping liquor through evaporation and crystallization processes, removing harmful substances from the discharge stream and converting them into useful products
Solution Approach 2:
The process recovers lignin and sugars that would otherwise be discarded as pollutants, transforming waste streams into valuable commercial products through evaporation, crystallization, and filtration operations
2Productivity
If strong acid hydrolysis is used to process lignocellulosic material, then cellulosic parts are hydrolyzed, but lignin remains as leftover solid with limited commercial applications
Solution Approach 1:
The invention changes the chemical parameters of lignin through controlled acid hydrolysis and evaporation processes, transforming it from an unreactive solid residue into a reactive product suitable for chemical synthesis applications
Solution Approach 2:
The process converts the previously harmful or useless acid treatment of lignin into a beneficial modification that enhances its reactivity and commercial value for chemical synthesis
3Quantity of substance
If Kraft pulping is used to precipitate lignin, then lignin can be recovered by acidifying spent pulping liquor, but the lignin undergoes condensing reactions and loses reactive properties
Solution Approach 1:
The invention performs preliminary evaporation and concentration of the pulping liquor before acidification, controlling the sequence of operations to prevent unwanted condensing reactions and preserve lignin reactivity
Solution Approach 2:
The process dynamically controls pH, temperature, and concentration parameters during lignin recovery to optimize both recovery quantity and preserve reactive properties, adjusting conditions to prevent condensing reactions
4Manufacturing precision
If solvent pulping is used to produce pure lignin, then lignin can be extracted in native form, but the process suffers from uncontrolled precipitation of sticky lignin that hardens at temperatures over 75° C.
Solution Approach 1:
The invention carefully controls temperature, pH, and concentration parameters during lignin precipitation, maintaining conditions that prevent uncontrolled sticking and hardening while achieving high purity recovery
Solution Approach 2:
The process uses controlled acidification and gradual pH adjustment with monitoring to prevent uncontrolled precipitation, ensuring lignin remains manageable and does not harden during the recovery process
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 achieves over 90% dissolution of lignin, producing a pure, reactive lignin that can be easily filtered and dried, with favorable conditions for hydrolyzing hemicelluloses, enabling its use as a feedstock for chemical synthesis and other applications.
Implementation Method 1
A solvent-based fractionation process using aliphatic alcohols, water, and sulfur dioxide to dissolve and separate lignocellulosic material into cellulose, hemicelluloses, and lignin
Implementation Method 2
lignocellulosic material is treated in a first stage with aliphatic alcohol, water and sulfur dioxide
Implementation Method 3
lignin is precipitated by reheating the liquor at low pH
Implementation Method 4
The hydrolyzate is then heated to precipitate water insoluble lignin
Implementation Method 5
The reheating of liquor causes precipitation of water insoluble lignin hydrolysis of the remaining hemicelluloses to monomeric sugars
Data Source
AI summary
A method for the production water insoluble reactive lignin having low sulfur content and lignosulfonates from lignocellulosic material in a batch or continuous process. Lignocellulosic material is fractionated to produce water insoluble native lignin and lignosulfonates in various ratios, while preserving the cellulose and hydrolyzed hemicelluloses using water, ethanol and sulfur dioxide.