Lignin Solvolysis via Recycled Solvent at Low Pressure
Solution Overview
Problem
Current hydrothermal liquefaction processes face challenges such as high operational pressures, equipment corrosion, and inefficient conversion of lignin to valuable chemicals due to harsh conditions, leading to low yields and high energy consumption.
Innovation Solution
A thermal liquefaction process that recirculates a recycled product fraction with a boiling point between 300° C. and 600° C. as a solvent, allowing for lower pressure operations and improved lignin conversion to renewable liquid products, which can be used as fuels or chemicals, while minimizing solid residues and oxygen content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrothermal liquefaction is carried out with liquid water at high temperatures (320-400°C), then lignin conversion to fuels and chemicals is achieved, but very high operational pressures (200 bar or above) are needed to keep water in liquid state
Solution Approach 1:
The patent changes the physical state parameter of the solvent from liquid water to supercritical carbon dioxide, which allows the process to operate at much lower pressures (1-10 bar) while maintaining the ability to convert lignin to valuable chemicals. This parameter change resolves the contradiction by enabling high productivity without requiring extremely high operational pressures.
Solution Approach 2:
The patent introduces carbon dioxide as an intermediary substance that mediates the liquefaction process. Instead of using water directly, CO2 serves as the solvent that enables lignin conversion under milder pressure conditions, thus resolving the pressure-productivity contradiction while maintaining effective lignin conversion.
2Productivity
If high operational pressures are used in hydrothermal liquefaction, then lignin conversion is achieved, but equipment corrosion and high equipment costs occur
Solution Approach 1:
By changing from high-pressure water-based systems to low-pressure CO2-based systems, the patent fundamentally alters the operational parameters to eliminate the harmful effect of equipment corrosion. The lower pressure and different chemical composition of CO2 prevent the corrosion issues associated with high-pressure water treatment, while still achieving effective lignin conversion.
3Productivity
If conventional thermal treatment processes are used for lignin conversion, then some fuel production is achieved, but tar and char formation occurs and significant amount of solid residues are produced
Solution Approach 1:
The patent uses supercritical carbon dioxide as an intermediary solvent that facilitates clean liquefaction of lignin. The CO2 medium enables complete solubilization and conversion of lignin to liquid fuels and chemicals without forming unwanted tars, chars, or solid residues, thus resolving the contradiction between fuel production yield and harmful byproduct formation.
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 high yields of good-quality liquid products at lower pressures, reducing equipment costs and operational challenges, and produces lignin-derived hydrocarbons suitable for biofuels and biochemicals, with improved product quality and reduced oxygen content.
Implementation Method 1
heating a feed mixture of lignin feedstock or lignin-based feedstock and recycled product fraction during a thermal liquefaction step at high temperatures and low pressure by recirculating a fraction(s) of the process as solvent
Implementation Method 2
thermal liquefaction of lignin, and more particularly to lignin solvolysis of a lignin feedstock or lignin-based feedstock
Implementation Method 3
converting lignin to renewable liquid product(s)... heating a feed mixture... during a thermal liquefaction step at high temperatures
Data Source
AI summary
The present disclosure relates to the thermal liquefaction of lignin, and more particularly to lignin solvolysis of a lignin feedstock (10) or a lignin-based feedstock (10). The process comprises subjecting a feed mixture (30) of lignin feedstock (10) or lignin-based feedstock (10) and solvent (20) to a thermal liquefaction step by heating (110) the feed mixture (30) at a temperature between 300 and 420° C. and at a pressure below 35 bar, wherein the solvent (20) of the feed mixture (30) is a recycled product fraction (61) separated (120) from the obtained liquid product mix (50). The present disclosure further relates to the use of the obtained product(s).