Lignin-Depleted Cellulosic Additive for Anaerobic Digestion
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Solution Overview
Problem
Current biogas production in anaerobic digesters is hindered by the presence of lignin in feedstocks, which reduces the rate of hydrolysis and limits methane production due to lignin's recalcitrance to biodegradation.
Innovation Solution
The method involves adding a lignin-depleted cellulosic material to the anaerobic digester, which has undergone delignification to reduce its lignin content to between 2 to 15%, thereby enhancing the accessibility of cellulose to microbial communities and increasing methane production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lignin-containing feedstock is used in anaerobic digester, then feedstock availability is improved, but methane production rate is reduced due to lignin's recalcitrance to biodegradation
Solution Approach 1:
The patent applies preliminary delignification treatment to the cellulose feedstock before introducing it to the anaerobic digester. This pre-treatment removes or reduces lignin content, making the cellulose more accessible to microbial degradation and thereby increasing methane production rate while maintaining feedstock availability
Solution Approach 2:
The patent changes the chemical composition parameter of the feedstock by reducing lignin content through delignification processes. This parameter change transforms recalcitrant lignin-containing cellulose into more biodegradable low-lignin cellulose, resolving the contradiction between feedstock availability and methane production rate
2Productivity
If delignification treatment is applied to reduce lignin content to 2-15%, then accessibility of cellulose to microbial communities is improved, but processing complexity increases
Solution Approach 1:
The patent extracts and removes lignin from the cellulose feedstock through delignification treatment. By taking out the problematic lignin component, the cellulose becomes more accessible to microbial communities without requiring overly complex digestion systems
Solution Approach 2:
The patent uses delignification treatment as an intermediary process that modifies the feedstock before anaerobic digestion. This intermediate step simplifies the overall system by pre-processing the cellulose to enhance microbial accessibility, avoiding the need for extremely complex digester designs
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 use of lignin-depleted cellulosic material significantly increases methane production, with experiments showing a nearly 2-fold increase in methane yield compared to using raw hardwood biomass, while also stabilizing the volume of methane produced.
Implementation Method 1
Biogases are the product of microbial degradation of various organic materials (both plant-based and animal-based products) in the absence of oxygen, i.e., in an anaerobic environment. This microbial degradation in an oxygen-free environment is called anaerobic digestion.
Implementation Method 2
The presence of lignin in feedstocks, which reduces the rate of hydrolysis and limits methane production due to lignin's recalcitrance to biodegradation.
Data Source
AI summary
In one example, a process to make biogas includes providing a digester which comprises at least one organic material rich in nitrogen and at least one inoculum capable of converting a portion of said at least one organic material into methane under anaerobic conditions; providing a biomass which is depleted of lignin; adding said biomass to said digester; allowing sufficient time for the digester to degrade at least a portion of said biomass and at least a portion of said organic material to yield a biogas composition comprising methane; capturing said biogas composition; and storing said biogas. Also disclosed, are methods and uses associated with the use of a cellulosic component processed to be depleted of lignin which comprises approximately between 10% to 50% of the amount of lignin present in a biomass component prior to a delignification treatment, as additive to organic waste in a bio-digester.