Lignin Extraction via Subcritical Water and Ethanol Fractionation
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Solution Overview
Problem
Current lignin extraction processes from lignocellulosic biomass are inefficient, leading to heterogeneous and modified lignin structures, which are not suitable for material synthesis or biofuel applications, and hemicelluloses are often degraded and not recovered, limiting the circularity and value derivation from biomass streams.
Innovation Solution
A consolidated biorefinery method using a green solvent system of water and ethanol, with optional inorganic acid, to fractionate hemicellulose and lignin, involving subcritical water extraction followed by ethanol-water extraction at controlled temperatures and pressures, minimizing lignin modification and preserving native structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional organosolv processes are used to extract lignin, then lignin can be obtained, but the lignin structure becomes heterogeneous and modified due to condensation reactions, making it unsuitable for material synthesis
Solution Approach 1:
The patent applies preliminary action by conducting hydrothermal pretreatment before the main organosolv extraction. This pretreatment step removes hemicellulose and prepares the biomass structure, preventing subsequent condensation reactions during lignin extraction and preserving the native lignin structure with high β-O-4' linkages.
Solution Approach 2:
The extraction process is segmented into two distinct stages: first hydrothermal extraction of hemicellulose, then organosolv extraction of lignin. This segmentation prevents interference between different extraction mechanisms and allows optimization of each stage independently, maintaining lignin structure integrity.
2Productivity
If high temperatures and acidic conditions are used to improve extraction efficiency, then more lignin is extracted, but condensation reactions increase forming stable C-C bonds that modify the lignin structure
Solution Approach 1:
The patent applies preliminary anti-action by removing hemicellulose through hydrothermal pretreatment before the organosolv extraction. This eliminates the source of condensation reactions that would otherwise occur during the main extraction, allowing efficient lignin extraction without structural modification.
Solution Approach 2:
The patent changes the extraction parameters by using a two-stage approach with different temperature and chemical conditions. The first stage uses hydrothermal conditions (high temperature, water), while the second stage uses milder organosolv conditions, thereby reducing condensation reactions while maintaining extraction efficiency.
3Device complexity
If hemicellulose is not separately extracted, then the process is simpler, but hemicellulose is degraded and lost, reducing the circularity and value of the biorefinery process
Solution Approach 1:
The patent segments the extraction process into two separate operations: hydrothermal extraction of hemicellulose followed by organosolv extraction of lignin. This segmentation enables recovery and valorization of hemicellulose while preventing its degradation, adding value to the biorefinery process.
Solution Approach 2:
The patent applies preliminary action by extracting hemicellulose first through hydrothermal treatment before proceeding to lignin extraction. This preliminary removal of hemicellulose prevents its degradation during subsequent processing and enables separate valorization pathways for different biomass components.
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 method achieves high-purity, high-yield extraction of lignin with a high degree of β-O-4' interunit linkage, suitable for material synthesis and biofuel applications, while also recovering hemicelluloses for further processing, enhancing the circularity and efficiency of the biorefinery process.
Implementation Method 1
providing lignocellulosic biomass and a first solvent in a first container, the first solvent being subcritical water
Implementation Method 2
The working principle of the organosolv process is to use an aqueous organic solvent to extract lignin, where low molecular weight aliphatic alcohols are especially used for the extraction
Implementation Method 3
heating the biomass and first solvent to a temperature of 110-170° C., while maintaining a pressure in said first container
Implementation Method 4
maintaining a pressure in said first container of from atmospheric pressure up to 2000 psi
Data Source
AI summary
The invention relates to a method for extraction of hemicellulose, lignin and carbohydrates from a lignocellulosic biomass, wherein the method comprises: 1) extracting hemicellulose from lignocellulosic biomass, by heating lignocellulosic biomass and subcritical water to 110-170° C., under a pressure of from atmospheric pressure up to 2000 psi, and letting hemicelluloses be extracted from the biomass, leaving a first fiber residue, and 2) extracting lignin and carbohydrates from said first fiber residue, by heating said first fiber residue and said second solvent comprising ethanol and water to 110-170° C., under a pressure of from atmospheric pressure up to 2000 psi, and letting lignin and carbohydrates be extracted from said first fiber residue, leaving a second fiber residue. 2) may be performed in a plurality of static cycles. The invention further relates to a lignin obtained by said method.