The special functionality has been internationally patented,
according to Patent-No. EP 2448415 B1
When considering the definition of "corrosion", you first think of aerobe corrosion where metal is distroyed under the influence of oxygen and water. However, a major part of all corrosion damages occur under full exclusion of oxygen, for instance in the bottom area of filled storage tanks or in pipeline systems.
Mainly responsible for the anaerobe corrosion are sulfate reducing bacteria (SRB). These micro-organisms accelerate corrosion of steel in crude oil tanks and other technical installations, which come in contact with water and organic materials. Such surfaces have to be cleaned continuously; otherwise, gel-like biofilms form due to the rapid propagation of SRB bacteria. This process causes biofouling with a strong smell and slime formation which could be a precursor of biocorrosion. Evidentially anaerobe biocorrosion causes a 10-times higher oxidation rate in comparison to atmospheric corrosion.
Coating without biociode
After a month-long test the coating was removed. The profilometric test photo shows heavy attack of the SRB. The steel reveals deep corrosion cavities.
Coating without biocide
After a month-long test the pickled test rod shows deep biocorrosion. (depth of corrosion cavity 150-200 µm)
Coating integrating a broad-band-biocide
After a month-long test the coating was removed. The profilometric test photo of the steel shows much less corrosion depth.
Coating integrating a broad-band-biocide
After a month-long test the pickled test rod shows much less corrosion depth. (depth of corrosion cavity 50-80 µm)
The SRB settle down primarily as tubercle-shaped colonies in niches with less circulation. They find optimum conditions in lower areas of filled oil tanks, for instance in cracks and pores of the coating.
Sulfate reducing bacteria (SRB) produce for the preservation of their O2-independent metabolism toxic hydrogen sulfide (H2S). The biocorrosion is caused by the enzyme hydrogenase, which is excreted by the SRB. This enzyme dismantles the protecting hydrogen film on the steel surface of the tank. Simultaneously, several redox reactions occur. Thus iron(II)sulfide is generated, which builds a black crust around the rust tubercles. By further physical-chemical reactions even high quality steel is destroyed.
Fatal and rapidly advancing pitting corrosion is the result. Even concrete substrates are extremely damaged by the SRB-produced hydrogen sulfide, which cause heavy concrete erosions.
The novel anti-SRB internal coatings of Ceramic Polymer GmbH prevent anaerobe biocorrosion from the beginning. The first population of SRB and the consequential building of rust tubercles in emerged micro cracks are provably avoided. The depot effect of the biocide crystals causes a long-lasting crack protection against SRB settlement.
Advanced biocorrosion in
bottom area of a steeltank
Extreme concrete erosions induced
by SRB-produced hydrogen sulfide
Significant properties of the new anti-SRB coating systems
Specific biocides in nano-crystalline shape
are integrated by a patent-protected method in a ceramic-filled polymer matrix.
Due to temperature gradients or mechanical impact, cracks in the range of nano- or micrometers occur in every coating during operation time. The SRB bacteria settle down primarily in those cracks, which appear as protective niches with low circulation. As soon as micro cracks occur in the coating, the special biocide crystals burst and unfold their effect within the whole crack. The SRB are killed before they can settle. The existing depot effect causes a long-lasting biocidal corrosion protection without localized erosion.
No negative impacts occur to the necessary bacterial processes in the biogas fermenter, because the biocidal effects are restricted locally to the micro cracks in the coating.
During the application procedure and also after the curing, the biocidal active component remains at first tightly encapsulated in the polymer matrix, so that the coated surface is not antiseptically active and therefore physiologically harmless. The kind of biocide employed is virtually harmless for humans. The application of these effective coating systems can easily be conducted by airless spraying method or roll and rake.
Extensive test series by our independent research partner have proven clearly that biocorrosion induced by SRB bacteria can be largely prevented by using our special coating products with patented functionality. Therefore, effective and targeted protection of concrete and steel substrates for biogas plants and tanks for crude oil and hydrocarbons is permanently achieved.