Digestate Drying Using Biomass Combustion Heat
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Solution Overview
Problem
Current methods for treating biogenic waste in anaerobic fermentation systems face challenges in efficiently processing oversize grain particles, which do not decompose and require separate disposal, and often produce liquid fermentation residues that are difficult to manage.
Innovation Solution
The method involves drying the digestate using heat from biomass combustion, including oversize particles, to produce a stable, storable product with reduced liquid residues, and utilizing a combination of a fermenter, drying device, and combustion device to optimize material flow and energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complex separation units are used to separate solid and liquid fermentation residues, then the separation efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent extracts and removes oversize grain particles from the fermentation mixture using a screening mechanism, separating them from the digestate without requiring complex separation units for all residues. This selective extraction approach simplifies the overall separation system while maintaining efficiency for the most challenging separation task.
Solution Approach 2:
The patent segments the residue separation process into two distinct stages: first separating oversize grain particles through screening, then handling the remaining digestate separately. This segmentation allows each stage to be optimized independently and reduces the complexity of any single separation unit required.
2Ease of manufacture
If wet fermentation is used, then the fermentation process is simpler, but the liquid fermentation residue becomes difficult to manage
Solution Approach 1:
The patent applies preliminary drying action to the digestate before final disposal or utilization. By removing excess moisture through drying equipment, the liquid fermentation residue is transformed into a more manageable solid or semi-solid form, eliminating the difficulties associated with managing liquid residues while maintaining the simplicity of the fermentation process itself.
3Stability of the object's composition
If dry matter content is increased in the fermenter, then the stability and storability of digestate is improved, but the humidity level must be maintained high enough for anaerobic digestion
Solution Approach 1:
The patent implements dynamic control of moisture content in the fermenter, adjusting it to optimal levels for anaerobic digestion during the fermentation process, then applying drying treatment after fermentation to achieve the desired stability and storability. This dynamic approach allows the system to optimize for different requirements at different stages.
Solution Approach 2:
The patent performs preliminary drying of the digestate after fermentation to achieve stability and storability. By removing excess moisture in a controlled manner following the fermentation process, the digestate is stabilized without compromising the humidity levels required during the actual anaerobic digestion phase.
4Productivity
If oversize grain particles are removed from the fermenter, then the fermentation efficiency is improved, but the material utilization is reduced
Solution Approach 1:
The patent converts the previously harmful or wasted oversize grain particles into a useful resource by implementing a combustion device that burns these particles to generate heat. This heat is then used to dry the digestate, transforming what was a loss of material into a beneficial energy source that improves overall material utilization and reduces waste.
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 approach allows for efficient anaerobic digestion with high dry matter content, eliminating liquid residues, and enables the reuse of oversize particles for heat generation, improving energy efficiency and material utilization.
Implementation Method 1
a combustion device for burning biomass in order to use heat from the combustion device for the drying device
Implementation Method 2
a drying device for drying the digestate from the fermenter
Implementation Method 3
biogenic waste is fermented anaerobically in a fermenter, with biogas and digestate being produced
Data Source
Figure 1
Figure 2
AI summary
In a digester, biogenic waste is anaerobically fermented to produce biogas and digestate. The digestate is dried using heat generated during the combustion of biomass.