Special project in Bergheim

The Between 2015 and 2016, the energy utility innogy SE constructed a modern plant for the production of biogas near Bergheim, west of Cologne in Germany’s Rhine-Erft district. With a capacity of 7.4 megawatts, it has since been feeding 700 cubic metres per hour of treated biomethane into the natural gas network – enough to provide around 3,300 households with heat and electricity. MC made an important contribution to protecting those surfaces of the plant exposed to a high level of chemical attack.
Biogas production in Bergheim relies on a mix of raw materials from the region’s agriculture. These are stored in silage chambers on site and then gradually fed into the fermentation process. The challenge in this system lies primarily in protecting the concrete of the clamp silo and the biogas production plant from media aggressive to concrete. The planning engineers GKE Consult International from Herne in Germany therefore put their faith in high-resistance product systems from MC.
An aggressive challenge

Organic acids which form in the digester vessel substrate as a result of the largely anaerobic fermentation process represent a problem for the durability of concrete. In the gas space, biogenic sulphuric acid (BSA) corrosion can occur, eventually leading to heavy corrosion of both the steel and the concrete components. Subcontracted by the construction company, the Essen-based firm of Massenberg GmbH used the duroelastic coating system MC-PowerPro HCR to protect the inside walls of the plant’s receiving hopper. This protects concrete from liquid manure, slurry and silage liquor while at the same time increasing its resistance to carbonation. Moreover, the coated surfaces are also resistant to BSA. A further useful side effect is the fact that the silage is less likely to adhere to the coated concrete surfaces, thus enabling it to slide more effectively down through the outlet of the receiving hopper.

All-round resistance

Another raw material with special properties used in the plant is dried chicken dung, which is kept in its own storage facility. This is also very aggressive in contact with concrete, so that durable, highly effective protection of the concrete walls and also the concrete floor plate of the storage building must be ensured. GKE Consult International decided here on the surface coating MC-RIM PROTECT-H, which was applied by ATil GmbH of Düren near Cologne. MC-RIM PROTECT-H is highly sulphate resistant and is particularly suitable for applying to horizontal surfaces. It is resistant to media with pH values from 14 down to 3.5 and also to temperature fluctuations, and it is water-impermeable. It likewise withstands even the heaviest mechanical wear and tear such as can occur during drive-on operations with a wheeled loader.
Tight joints

The clamp silo was exposed to damage to its joints due to a level of beet content in the silage that had not been envisaged at the planning stage. Hence the old jointing compound had to be removed and replaced by a more resilient technology. The emergency was averted through application of the jointing system Mycoflex Resyst from MC. This enables expansion joints and vertical joints in the wall area to be reliably resealed against even aggressive environments. Mycoflex Resyst consists of prefabricated mouldings made from a special polymer foam. These effectively protect joints from aggressive chemicals with a more resilient seal. A series of tests was carried out which served to fully convince the site management, the VAwS* inspectorate and the planning engineers on site of the excellent merits of Mycoflex Resyst.Thus, chemical-resistant coating and jointing systems from MC continue to reliably and sustainably protect both the biogas plant in Bergheim and the environment.