Continuous Lignin Fractionation With Solvent Recycling and Flow-Through Beds
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Solution Overview
Problem
Reductive catalytic fractionation (RCF) processes face challenges with high solvent consumption, long residence times, and complex operations, hindering the scale-up of lignin valorization from biomass due to expensive reactors and inefficient solvent usage.
Innovation Solution
Implementing solvent recycling and multiple solvolysis chambers with physical agitation, such as a screw extruder, to reduce solvent loading and enhance lignin extraction, along with flow-through configurations and in-situ pressure filtering to recover solvent, thereby reducing reactor costs and improving monomer yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high solvent loading (9 g solvent to 1 g biomass) is used for lignin extraction, then extraction efficiency is improved, but solvent consumption increases and process economics deteriorate
Solution Approach 1:
The patent implements solvent recycling where the solvent containing extracted lignin is recovered and reused for subsequent extraction cycles. This allows maintaining high extraction efficiency across multiple batches while significantly reducing total solvent consumption, directly addressing the contradiction between extraction efficiency and solvent quantity.
Solution Approach 2:
The patent employs continuous flow-through reactors where solvent continuously flows through biomass beds, enabling uninterrupted extraction operations. This continuous operation maintains consistent extraction efficiency while optimizing solvent utilization through multiple passes, reducing overall solvent requirements compared to batch processes.
2Ease of manufacture
If batch reactors are used for RCF processing, then reactor cost is reduced, but residence time increases and productivity decreases
Solution Approach 1:
The patent divides the processing system into multiple parallel flow-through reactor units, each handling a portion of the total biomass load. This segmentation allows continuous processing across multiple units simultaneously, maintaining high productivity while using simpler, lower-cost flow-through reactor designs rather than complex batch reactors.
Solution Approach 2:
The flow-through reactor design enables continuous solvent flow and continuous extraction, eliminating the start-stop nature of batch operations. This continuous operation dramatically reduces residence time and increases throughput while maintaining reactor design simplicity and affordability.
3Ease of manufacture
If semi-continuous reactors with frequent biomass changeout are used, then reactor cost is reduced, but operational complexity and operating cost increase
Solution Approach 1:
The patent implements continuous flow-through operation where solvent continuously passes through fixed biomass beds without requiring frequent biomass removal or replacement. This eliminates the operational complexity of semi-continuous systems while maintaining simple reactor design, achieving both low capital cost and operational simplicity.
Solution Approach 2:
Biomass is pre-loaded into the flow-through reactors in large quantities before operation begins, establishing long-lasting biomass beds that process solvent continuously without interruption. This preliminary loading eliminates the need for frequent biomass changeout operations, simplifying operational procedures while maintaining simple reactor construction.
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
Achieves efficient lignin monomer production with reduced solvent usage, maintaining monomer yields even after storage, and enabling continuous processing without immediate catalytic reaction, facilitating economic and sustainable lignin valorization.
Implementation Method 1
physical agitation (e.g., use of a screw extruder) to reduce the amount of solvent required
Implementation Method 2
incorporates in-situ pressure filtering to recover a greater fraction of the solvent in a single unit operation
Implementation Method 3
treating biomass with a solvent, thereby extracting lignin and generating a solvolysis liquor
Implementation Method 4
reacting the solvolysis liquor in the presence of a catalyst, thereby generating at least one lignin monomer
Implementation Method 5
a reducing atmosphere with metal catalyst to cleave specific lignin bonds
Data Source
AI summary
Described herein are devices and methods for the efficient and economic generation of lignin monomers from biomass. The provided devices and methods utilize reductive catalytic fractionation with an organic solvent to extract high-quality lignin from biomass and cleave specific lignin bonds to generate valuable lignin monomers with a relatively narrow product slate. Advantageously, the devices and methods described herein utilize solvent recycling, multiple solvolysis chambers with multiple biomass beds and/or physical agitation (e.g., use of a screw extruder) to reduce the amount of solvent required and increase economic efficiency and monomer yield.