Biochar and Hydrogen Production from Fermented Straw
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Anaerobic fermentation byproducts from biogas digesters pose environmental and health risks due to nitrogen excess, pathogenic bacteria, heavy metal pollution, and inefficient resource utilization, with current hydrogen production methods being costly and requiring high temperatures, leading to side reactions.
Innovation Solution
A method involving anaerobic fermentation of straw with seeding sludge and water to produce biochar and hydrogen, where the fermented straw is carbonized to create biochar with a high specific surface area, and biogas slurry is processed in a pressurized catalytic reaction to produce hydrogen under mild conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If anaerobic fermentation byproducts are used as bio-organic fertilizers, then nitrogen nutrition is provided to crops, but soil nitrogen excess, pathogenic bacteria, and heavy metal pollution occur
Solution Approach 1:
The patent extracts and removes harmful components (pathogenic bacteria, heavy metals, excess nitrogen) from the biogas slurry through a multi-step treatment process including filtration, adsorption, and biological degradation, leaving only the useful organic matter for fertilizer application
Solution Approach 2:
The patent converts the harmful characteristics of biogas slurry (high nitrogen content causing pollution, presence of pathogenic bacteria) into beneficial properties by controlling the anaerobic fermentation process to produce stable, safe organic fertilizer that provides sustained nitrogen release without environmental harm
2Quantity of substance
If biogas slurry is used as fertilizer, then organic nutrition is provided, but acceptability is low and availability for farmers is only about 30%
Solution Approach 1:
The patent changes the physical and chemical parameters of biogas slurry through controlled anaerobic fermentation, transforming it from a liquid slurry with poor storage and transport properties into a stable solid or semi-solid organic fertilizer with improved handling characteristics and higher farmer acceptability
3Quantity of substance
If direct pyrolysis of straw is performed to produce biochar, then biochar is obtained, but tar blocks pores resulting in small specific surface area
Solution Approach 1:
The patent performs preliminary anaerobic fermentation treatment on the straw before pyrolysis, pre-decomposing the lignocellulose structure to reduce tar formation during subsequent carbonization, thereby avoiding pore blockage and achieving higher specific surface area biochar
Solution Approach 2:
The patent skips the intermediate step of tar accumulation by using pre-fermented biomass, allowing the pyrolysis process to proceed directly to biochar formation without the tar blocking pores that would occur with direct pyrolysis of untreated straw
4Quantity of substance
If steam reforming is used for hydrogen production from biogas slurry, then hydrogen is produced, but high temperature (500-700°C) and normal pressure are required with side reactions occurring
Solution Approach 1:
The patent changes the reaction parameters from high temperature (500-700°C) and normal pressure to mild conditions (lower temperature and elevated pressure), enabling hydrogen production from biogas slurry through catalytic reforming without requiring extreme thermal conditions and minimizing side reactions
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 method effectively increases the specific surface area of biochar, enhances its performance, and produces hydrogen efficiently with reduced side reactions, offering a cost-effective and environmentally friendly solution for resource recycling and disposal of anaerobic fermentation byproducts.
Implementation Method 1
mixing a first straw, seeding sludge, and distilled water for anaerobic fermentation to obtain a fermented mixed product
Implementation Method 2
carbonizing the obtained second straw to obtain the biochar
Implementation Method 3
collecting the gas, i.e., the hydrogen, after a pressurized catalytic reaction of the obtained biogas slurry
Data Source
AI summary
A method for preparing biochar and hydrogen by utilizing anaerobic fermentation byproducts, the method including: (1) mixing a first straw, seeding sludge and distilled water, and then carrying out anaerobic fermentation to obtain a mixed product after fermentation; (2) performing separation on the mixed product to obtain a second straw and biogas slurry; and (3) carbonizing the second straw to obtain biochar, and collecting gas after a pressurized catalytic reaction on the biogas slurry to obtain hydrogen.