Lignin Depolymerization in Black Liquor

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Solution Overview

Problem

Current methods for lignin depolymerization are inefficient and costly, requiring multiple steps and additional reagents, making them unsuitable for industrial scale and environmentally incompatible.

Innovation Solution

A method involving alkaline treatment of biomass to produce black liquor, followed by concentration, hydrothermal treatment, acid addition, and liquid-liquid extraction to obtain high-value phenolic products, reducing the complexity and environmental impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If current methods use precipitation steps with additional reagents and filters to isolate solid lignin before depolymerization, then lignin can be obtained for treatment, but the process complexity and cost increase significantly

Engineering Contradiction:
Improveprocess simplicityVSAvoidprocess steps
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention extracts and utilizes lignin directly from the black liquor solution without removing it as a separate solid phase. By performing depolymerization in situ within the liquid medium, the method eliminates the need for precipitation, filtration, and drying steps that would otherwise be required to isolate solid lignin, thereby simplifying the overall process while maintaining effectiveness

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the depolymerization step with the existing black liquor treatment process. Instead of separating lignin first and then treating it independently, the method combines these operations by directly treating the dissolved lignin in the black liquor, reducing the number of discrete process steps and integrating functions

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If current methods precipitate lignin using acid and additional reagents, then solid lignin is obtained for depolymerization, but the environmental impact and cost increase

Engineering Contradiction:
Improvemethod costVSAvoidenvironmental impact
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention converts the typically harmful or waste black liquor stream into a valuable resource by performing depolymerization directly in this medium. What would otherwise require costly and environmentally problematic treatment and disposal is instead transformed into a source of aromatic compounds, turning a liability into an asset and eliminating the need for additional reagents

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The black liquor itself serves as the reaction medium for depolymerization, eliminating the need for additional reagents, solvents, or processing aids. The system uses its own existing composition to facilitate the chemical transformation, reducing external inputs and waste generation

Inventive Principle:
Principle #25Self-service

3Productivity

If current methods start from precipitated solid lignin, then depolymerization can proceed, but the overall process efficiency decreases due to extended treatment time

Engineering Contradiction:
Improveprocess efficiencyVSAvoidtreatment time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The invention performs depolymerization on dissolved lignin in the black liquor before any precipitation or isolation steps would be required. By acting on the lignin while it is still in solution, the method eliminates subsequent time-consuming steps such as filtration, drying, and re-suspension, thereby reducing total treatment time and improving productivity

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3072874B1Novel method for the depolymerisation of lignin
Publication Date: 2019.05.29 UNIV DEL PAIS VASCO EUSKAL HERRIKO UNIBERTSITATEA
  • EP3072874B1 patent drawingFigure 1
  • EP3072874B1 patent drawingFigure 2
  • EP3072874B1 patent drawingFigure 3~4

AI summary

The invention relates to a novel method for the depolymerization of lignin, comprising the steps of: providing a black liquor obtained from the treatment of delignification of the biomass: concentrating said black liquor; subjecting the concentrated black liquor to a hydrothermal treatment; adding an acid to the reaction mixture obtained in the previous step; separating the precipitate from the liquid phase resulting in the previous step; and extracting, from the recovered liquid phase, the aromatic products of depolymerization of lignin, such as phenol, cresols, catechol and the derivatives thereof (3-methylcatechol, 4-methylcatechol and 4-ethylcatechol).