case study:
During an assessment of anaerobic digestion gas leaks, it was found that the Anaerobic Digester was releasing biogas into the surrounding environment. This leakage caused financial losses, environmental harm, and posed safety hazards on-site. The presence of sulphur staining made the gas leak visible and brought attention to the issue.
OUR SOLUTION
To address gas leaks in the Anaerobic Digester, we decided to employ the same polyurea technology that had previously proven effective in sealing localized leaks using our Polyurea Products. This decision led us to treat all roof-to-roof joints and the junction between the circumferential wall and the roof with this polyurea material.
The reason for choosing this polyurea technology initially was its capability to withstand up to 6 bar of negative pressure, which far exceeds the pressure of the gas present within the digester. Additionally, this polyurea material is highly resistant to chemicals and can endure the levels of hydrogen sulphide found in biogas.
To prepare the concrete surfaces on the anaerobic digester tank roof and vertical faces, we employed vacuum-controlled diamond grinding to eliminate contaminants and surface laitance, ensuring excellent adhesion of the primer and subsequent polyurea gas seal.
All surfaces to be coated were thoroughly vacuumed, and moisture content of the concrete was tested and recorded to meet our standard polyurea application quality assurance. Climatic conditions were also evaluated before applying the damp-tolerant epoxy primer, which was brushed and rolled onto the surfaces, with an aggregate dressing applied into the wet resin to provide a solid mechanical anchor for the subsequent polyurea application. This step also served as insurance against poor adhesion resulting from amine blush/blooming that may occur due to external conditions.
To complete the sealing process, polyurethane jointing compound was used to fill all joints after backing rod placement. Pipes and other items not requiring coating were masked off to protect them from overspray damage.
Finally,ArmorThane ArmorLiner polyurea, was applied to a thickness of 2mm. To ensure the integrity of the polyurea, a DC Holiday spark tester was employed to detect any pinholes that could lead to gas leaks once the anaerobic digester was filled and back in operation.
To accommodate our client’s strict timeline and minimize the downtime of the anaerobic digester, our team worked through the weekend, which the client greatly appreciated.
The applicator ended the project by conducting tests on the polyurea applied substrate. This involved affixing 20mm dollies to the surface. After allowing the glue to set for 24 hours, the dollies were then drilled using a 20mm coring hole bit.
Case Details
Client Details
Center Enamel Co
Service Provided
Coated leaking areas of the digester tanks.
Project Timeline
5 Days spraying application,
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