Biomethanisation Facility Solid Fraction Handling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for managing urban solid waste through biogas production pose a risk of explosion due to the transition of anaerobic to aerobic conditions during the handling of solid fractions, and there is a need for a safer method to obtain both a usable organic soil conditioner and a liquid fertilizer.
Innovation Solution
Implementing an anaerobic fermentation step followed by separation, feedback of a liquid fraction as inoculum, additional fermentation with methanogenic bacteria, filtering and chemical treatment of the liquid, drying of the solid fraction at 65°C or higher to neutralize bacteria, and milling for use as soil conditioner or animal feed, with optional inerting and power generation from biogas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the solid fraction is conveyed on non-waterproof belts from the bioreactor to the centrifuge and from this latter one to the composting beds, then the organic pulp can be transported and processed, but the solid fraction captures oxygen and reaches residence conditions with oxygen content between 6% and 8%, creating a risk of explosion due to the presence of methane and oxygen mixture
Solution Approach 1:
The patent applies inerting by introducing nitrogen or carbon dioxide to displace oxygen from the atmosphere surrounding the solid fraction during transport and storage. This creates an oxygen-deficient environment (below 6% oxygen) that prevents the formation of explosive methane-oxygen mixtures, thereby eliminating the explosion hazard while maintaining operational ease of transport on conveyor belts
2Productivity
If the solid fraction is subjected to aerobic fermentation on composting beds, then the organic matter can be transformed into compost for soil fertilizer and forestry industry use, but the presence of residual anaerobic bacteria and oxygen exposure creates explosive conditions
Solution Approach 1:
The patent implements preliminary inerting of the solid fraction immediately after centrifugation and before it reaches the composting beds. By establishing the oxygen-deficient atmosphere in advance, the system enables safe aerobic composting to proceed without the risk of explosive conditions developing during the composting process
3Ease of manufacture
If the liquid fraction is rejected after centrifugation, then the separation process is completed, but the liquid fraction containing valuable nutrients and methanogenic bacteria is wasted
Solution Approach 1:
The patent implements a feedback loop where a portion of the liquid fraction from centrifugation is returned to the bioreactor as inoculum to maintain methanogenic bacterial populations. Additionally, the liquid fraction is directed to anaerobic digesters for biogas production, thereby recovering nutrients and energy while completing the separation process
4Loss of time
If the solid fraction is used directly after centrifugation, then the processing time is reduced, but the solid fraction remains subject to anaerobic fermentation and poses explosion risks during handling
Solution Approach 1:
The patent applies preliminary inerting treatment to the solid fraction immediately after centrifugation, before any further handling or transport operations. This preliminary action of removing oxygen prevents the formation of explosive atmospheres during subsequent handling, allowing the process to proceed efficiently without time delays while maintaining safety
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
This method safely generates biogas and produces stable solid and liquid fractions for fertilizer and animal feed, reducing explosion risks and enhancing the usability of waste products while providing a self-sustaining energy source.
Implementation Method 1
an anaerobic fermentation step of the organic pulp obtained from urban solid waste, with the help of anaerobic bacteria
Implementation Method 2
a fermentation step of the remaining liquid fraction by means of methanogenic bacteria, to obtain methane
Implementation Method 3
a drying step of the solid fraction obtained after the separation step, in order to neutralize the bacterial flora present at such solid fraction through the application of heat
Implementation Method 4
drying of the solid fraction at 65°C or higher to neutralize bacteria
Implementation Method 5
a separation step to obtain a liquid fraction or lixiviate, plus a solid fraction of the residues, obtained from the digested slurry or fermented organic pulp
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method for operating a facility for the biomethanisation of solid organic waste and to the facility used for same. The method includes: a step comprising the anaerobic fermentation of an organic paste load ; a separation step used to obtain a leachate or liquid fraction (FL), and a solid fraction (FS), a step comprising the return of the liquid fraction part (PFL), a step comprising the storage and fermentation step of the remaining liquid fraction (RFL), a step comprising the filtration of the residual liquid from the fermentation step for physical/chemical treatment in order to obtain liquid fertilizer; a step comprising the grinding of the solid fraction (FS) in order to treat same so that it can be used as an organic soil conditioner and/or as a raw material for organic feed; a step comprising the drying of the separated solid fraction (FS), for heat-based neutralisation of the bacterial flora present in said solid fraction.