Polyurea Coating for Biogas Tank Acid Resistance

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Solution Overview

Problem

Concrete and metal surfaces in biogas plants and slurry tanks are prone to acid degradation and leakage, requiring frequent and costly renovations, while contaminated demolition materials pose a risk of environmental contamination during storage and transport.

Innovation Solution

Applying insulating panels to the inner walls of containers followed by an elastic polyurea coating, which creates a durable, acid-resistant, and moisture-impermeable layer that adapts to material movements and provides high chemical resistance, preventing erosion and contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If concrete surfaces are used in biogas plants, then construction is simple and cost-effective, but the concrete decomposes due to acid exposure and requires frequent renovation

Engineering Contradiction:
Improveconstruction simplicityVSAvoidacid resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies a composite material system consisting of multiple layers: a primer layer (epoxy or polyester resin), an intermediate layer (cement-based or polymer-modified mortar), and a top layer (polyurethane or polyaspartic coating). This multi-layer composite structure combines the advantages of concrete construction simplicity with the chemical resistance of polymer materials, creating a protective system that resists acid exposure while maintaining ease of application.

Inventive Principle:
Principle #40Composite materials

2Reliability

If stainless steel containers are used, then acid resistance is improved, but the stainless steel is still attacked and leaks occur

Engineering Contradiction:
Improveacid resistanceVSAvoidconstruction complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of relying on expensive stainless steel that can still be attacked, the patent employs a cost-effective multi-layer coating system that provides sufficient protection against acid exposure. The coating system acts as a sacrificial protective barrier that can be applied to conventional concrete or metal substrates, offering reliable acid resistance without the high cost and complexity of stainless steel construction.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If concrete renovation is performed by removing upper layers and rebuilding, then acid protection is restored, but the process is time-consuming and costly

Engineering Contradiction:
Improveacid protectionVSAvoidrenovation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies a multi-layer coating system that serves as a preliminary protective action against future acid damage. Rather than waiting for concrete degradation and then performing extensive renovation, the coating system is applied in advance to prevent acid attack, thereby eliminating the need for time-consuming removal and rebuilding operations. The system includes proper surface preparation, primer application, and multiple coating layers that collectively provide long-lasting acid protection.

Inventive Principle:
Principle #10Preliminary action

4Ease of manufacture

If demolition materials from nuclear power plants are stored without treatment, then storage is simple, but radioactive particles can enter the environment through erosion

Engineering Contradiction:
Improvestorage simplicityVSAvoidenvironmental contamination
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent employs a flexible, multi-layer coating system that forms a continuous protective shell around demolition materials. The system includes a primer layer for adhesion, an intermediate layer for structural protection, and a top layer with UV stability and chemical resistance. This flexible film structure conforms to irregular shapes of demolition materials and provides comprehensive protection against erosion and radioactive particle release, while maintaining relatively simple application procedures.

Inventive Principle:
Principle #30Flexible shells and thin films

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 solution extends the service life of biogas plants and slurry tanks, allows for cost-effective and quick application, and effectively prevents radioactive particle leakage, ensuring long-term containment of contaminated materials without the need for frequent renovations.

Implementation Method 1

The elastic coating made of polyurea creates a moisture-impermeable layer with acid-resistant properties

Methodology Applied
Scientific EffectMoisture impermeability:

Implementation Method 2

The elastic coating made of polyurea creates a moisture-impermeable layer with acid-resistant properties that is not only durable, but also has elasticity so that material movements of the concrete or metal surfaces do not destroy the elastic coating, for example by tearing

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

The elastic coating made of polyurea creates a moisture-impermeable layer with acid-resistant properties

Methodology Applied
Scientific EffectChemical resistance:

Implementation Method 4

an elastic coating made of polyurea or a polyurea mixture

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3611315B1Tank of a biogas plant or slurry tank
Publication Date: 2023.11.01 WIEGRINK BETEILIGUNGS
  • EP3611315B1 patent drawingFigure 1
  • EP3611315B1 patent drawingFigure 2
  • EP3611315B1 patent drawingFigure 3

AI summary

The invention relates to a method for treating demolition materials and concrete or metal surfaces, in particular those of biogas plants, slurry tanks, sewage treatment plants, flat roofs, basement walls, collection basins, or water tanks, some of which may contain radioactive substances. To treat concrete and metal surfaces and protect them from aggressive media, or alternatively to seal demolition materials, the invention provides that, in the case of concrete and metal surfaces, insulating panels or polyurethane foam are applied, followed by the application of an elastic coating over the insulating panels or polyurethane foam. If demolition materials are present, they can also be provided with an elastic coating consisting of polyurea or a polyurea mixture with a polyurea content of 1 to 95%.The polyurea coating protects the concrete or metal surfaces being renovated. Coating the demolition materials, which preferably originate from decommissioned nuclear power plants, largely prevents contamination of the surrounding area by the radioactive materials.