Biogas Digester Liquid Digestate Percolation Mixing

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Solution Overview

Problem

Current biogas production systems face challenges in efficiently processing solid biomass due to difficulties in handling and preparing heterogeneous materials, leading to high energy expenditure, equipment damage, and increased maintenance costs, as well as issues with biogas purification and odor management.

Innovation Solution

A biogas production system comprising a central liquid digestate storage and complementary digestion unit, anaerobic digesters with integrated solid biomass intake and liquid digestate supply/evacuation networks, allowing direct introduction and processing of solid biomass without pre-treatment, and utilizing percolation and diffusion of liquid digestate for anaerobic digestion, which reduces the need for mechanical agitation and equipment investment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solid biomass is directly introduced into anaerobic digesters without pre-treatment, then equipment damage and maintenance costs are reduced, but the efficiency of biomass degradation and biogas production decreases

Engineering Contradiction:

Improveequipment reliabilityVSAvoidbiogas production efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-treating solid biomass outside the digester through size reduction (crushing/grinding) and screening to remove contaminants before introduction. This preparation work is done in advance using separate equipment, preventing damage to digester machinery while maintaining high degradation efficiency through proper particle size control (0.5-5mm).

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the biomass processing function from the digestion function. A separate pre-treatment unit with crusher and screen is used to prepare biomass, which is then introduced into the digester. This segmentation protects the digester from handling rough materials while ensuring optimal substrate conditions for microbial degradation.

Inventive Principle:

Principle #1Segmentation

2Productivity

If mechanical agitation systems are installed in digesters to mix solid biomass, then degradation efficiency improves, but equipment complexity and investment costs increase

Engineering Contradiction:

Improvebiomass degradation efficiencyVSAvoiddigester equipment complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical agitation systems with a simpler percolation-based mixing approach. Liquid digestate is circulated through the biomass bed using pumps and distribution systems, creating natural convection and diffusion currents that achieve adequate mixing without requiring mechanical stirrers or agitators inside the digester.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses hydraulic circulation of liquid digestate to achieve mixing. Pumps circulate liquid through distribution pipes that spray or infiltrate the biomass, creating fluid flow patterns that enhance contact between substrate and microorganisms without mechanical moving parts in the digester.

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Productivity

If continuous stirring is performed in liquid methanization processes to prevent settling, then biomass-microorganism contact is improved, but energy expenditure increases significantly

Engineering Contradiction:

Improvecontact efficiency between biomass and microorganismsVSAvoidenergy for agitation

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent uses periodic circulation of liquid digestate instead of continuous stirring. Pumps operate in cycles to circulate liquid through the biomass bed, creating periodic flow patterns that maintain adequate mixing and contact while allowing energy-saving idle periods between circulation cycles.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system uses the weight and flow of liquid digestate itself to create mixing action. The circulating liquid provides the mechanical energy for mixing through its own hydrodynamic forces, eliminating the need for separate high-energy agitation systems.

Inventive Principle:

Principle #25Self-service

4Ease of operation

If solid biomass is ground to facilitate transport and mixing, then handling efficiency improves, but equipment damage from contaminants increases

Engineering Contradiction:

Improvebiomass handling efficiencyVSAvoidequipment reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent extracts contaminants (stones, metals, plastics) from the biomass stream using screening equipment before the grinding stage. This removal of harmful elements prevents damage to grinding machinery and transport equipment while maintaining the size reduction benefits for efficient handling and degradation.

Inventive Principle:

Principle #2Taking out (Extraction)

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 enhances the efficiency of solid biomass utilization, decreases energy and maintenance costs, minimizes equipment damage, and improves biogas recovery and purification, while effectively managing odors and reducing operational expenses.

Implementation Method 1

a step of filling the tank of said digester with liquid digestate to immerse the solid biomass, a digestion step, consisting of percolation of the liquid digestate through the solid biomass contained in said digester and of a diffusion of the liquid digestate into said solid biomass under anaerobic conditions

Methodology Applied

Scientific EffectPercolation:

Implementation Method 2

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 3

Anaerobic digestion (also called anaerobic digestion) is a natural biological process which involves the degradation of organic matter by several types of micro-organisms, in particular bacteria, under controlled conditions and this in the absence of oxygen

Methodology Applied

Scientific EffectAnaerobic digestion: Anaerobic Digestion

Data Source

PatentEP3541921B1System for producing biogas from solid biomass and corresponding biogas method

Publication Date: 2020.07.01 YANNCO

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AI summary

The present invention concerns a system for producing biogas, comprising at least one central unit for liquid digestate storage and additional digestion (1), at least one central biogas storage unit, a plurality of anaerobic digesters (100, 101, 102, 103, 104), a liquid digestate (5) supply network (33), a liquid digestate (5) discharge network (35) and a biogas (25) discharge network (34); at least one solid biomass digester (100, 101, 102, 103, 104) and at least one central unit for liquid digestate storage and additional digestion are heat-insulated. The invention also concerns a method for producing biogas.