Corrosion protection for chimney at bio-methane plant

The plant processes the sludge remaining after sewage treatment to produce bio-methane, which is an alternative source of energy to fossil fuels. Bio-methane production offers a number of other environmental benefits including stopping the release of methane and other harmful gases produced by organic matter decomposing into the atmosphere.

In service the 1.2m diameter chimney, which was in three sections (30m in all), will be exposed to a range of waste gases including hydrogen sulphide, so protecting it by lining with a specialist coating system would extend its service life and reduce future maintenance down time.

At its Leeds factory, Corroserve first abrasive blast cleaned all the internal surfaces in accordance with ISO8501- 1 Sa2½, to remove heavy mill scale and provide the required surface profile for coating. This was followed by the application of multiple coats of Polyglass VEF – spray applied using Agmec internal pipe spraying equipment to achieve a DFT of 1250μm. 

Corroserve says Polyglass VEF is excellent for use in aggressive environments where superior resistance to chemical attack in immersed and non-immersed conditions is essential. It provides excellent protection against corrosion across the full pH range.

The Agmec pipe sprayer is part of the Corrocoat range of internal pipe blasting and spray equipment.  Developed to coat pipe internals from 100-2000mm diameter, it uses centrifugal force produced by a specially developed spray cup.  A fan spray pattern is produced by the multi-axial head, which provides a precise and consistent finish at a predetermined thickness.  A constant-speed winch draws the sprayer through pipes up to 150m long. 

The contract was completed quickly and efficiently and the chimney installed on site shortly thereafter. The client is satisfied that the new lining will protect it from corrosion attack for a considerable time and remains confident that they have a long-term cost-effective solution, particularly when compared with the cost of repairing or replacing the chimney in the future.