Nanoporous Membrane Pretreatment for Lignocellulosic Biomass
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Solution Overview
Problem
Existing pretreatment methods for lignocellulosic feedstocks, such as flow-through and steam pretreatment, result in partial thermochemical depolymerization and degradation of carbohydrates and lignins, leading to sugar losses and the formation of inhibitory compounds that hinder fermentation, necessitating an improved method to retain carbohydrates and lignins while producing a superior concentrate of reactive organics.
Innovation Solution
A process utilizing an inorganic nanoporous membrane element to separate solubilized compounds from a pressurized, high-temperature hydrolyzate stream, recycling the solvent-rich permeate and fractionating the retentate enriched in solubilized organic components, which are then fermented to produce ethanol, thereby minimizing sugar degradation and inhibitor formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flow-through pretreatment or steam pretreatment is used, then the feedstock is hydrolyzed into fermentable sugars, but sugar losses and inhibitory compounds are formed
Solution Approach 1:
The patent employs a nanoporous membrane with precisely controlled pore sizes (0.5-2.0 nm) to separate solubilized compounds from the hydrolyzate stream. The porous structure allows selective passage of molecules based on size, enabling retention of sugar molecules while permitting passage of smaller degradation products and inhibitors, thus resolving the contradiction between hydrolysis efficiency and sugar loss
Solution Approach 2:
The invention extracts harmful components (inhibitory compounds and degradation products) from the hydrolyzate stream by passing it through the nanoporous membrane. This separation process removes the harmful factors that cause sugar losses and fermentation inhibition, while retaining the valuable fermentable sugars in the retentate stream
2Ease of manufacture
If flow-through pretreatment is used, then the process operates at lower costs, but material costs are higher compared to steam pretreatment
Solution Approach 1:
The patent recovers valuable solubilized organics and sugars that would otherwise be lost in conventional pretreatment. By using the nanoporous membrane to separate and retain these compounds in the retentate stream, the system converts what would be waste or loss into recoverable valuable materials, thereby reducing overall material costs while maintaining process efficiency
3Productivity
If conventional pretreatment methods are used, then hydrolysis occurs, but inhibitory compounds are formed that hinder fermentation
Solution Approach 1:
The invention converts the harmful effect of thermochemical depolymerization into a beneficial separation opportunity. By allowing controlled depolymerization to occur and then using the nanoporous membrane to separate the resulting mixture, the system transforms what would be harmful degradation products into a separable stream, enabling removal of inhibitors while retaining valuable sugars for fermentation
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 carbohydrate retention rates, minimal sugar degradation, and enhanced ethanol yield by selectively retaining solubilized organics, reducing inhibitor presence, and optimizing energy usage, with laboratory testing demonstrating improved glucan conversion rates compared to conventional methods.
Implementation Method 1
separating solubilized compounds from the hydrolyzate exit stream using an inorganic nanoporous membrane element
Implementation Method 2
The size of the solutes excluded in this separation are on the order of one nanometer and can include a molecular weight of less than 200 Da
Implementation Method 3
When a pressure differential sufficient to maintain solubilized compounds in the liquid phase is applied across the membrane
Implementation Method 4
flowing water through a pretreatment reactor containing a bed of particulate lignocellulosic biomass to produce a pressurized, high-temperature hydrolyzate exit stream
Data Source
AI summary
A process for the pretreatment of lignocellulosic biomass is provided. The process generally includes flowing water through a pretreatment reactor containing a bed of particulate ligno-cellulosic biomass to produce a pressurized, high-temperature hydrolyzate exit stream, separating solubilized compounds from the hydrolyzate exit stream using an inorganic nanoporous membrane element, fractionating the retentate enriched in solubilized organic components and recycling the permeate to the pretreatment reactor. The pretreatment process provides solubilized organics in concentrated form for the subsequent conversion into biofuels and other chemicals.