US130: Corrosion Protection of Mild Steel Chimney at a Bio-Methane Plant

Industry: Bio-methane plant

Environment: Exposure to waste gasses

Protection from Corrosive Gasses

A 1.2m diameter chimney, manufactured from mild steel,
required internal lining along the full length of three 10m
long sections. The newly fabricated chimney was due to
be installed at a bio-methane plant in operation in the
north east of England.

The plant uses the sludge remaining after sewage
treatment to produce renewable electricity. It captures the
bio-methane released by bacteria digesting the sludge
and converts it to electricity to power the plant. Any
access scan be scrubbed and sold back to the grid as
natural gas.

In service the chimney required protection from a number
of gases at ambient temperature and at a maximum flow
rate of 7000m³/h.
3.45 mg/m³ Hydrogen sulphide (H S)
0.055 mg/m³ Dimethyl sulphide (DMS)
0.025 mg/m³ Pentanethiol (Ptol)
0.03 mg/m³ Diethyl disulphide (DEDS)
By lining the chimneys components with specialist coatings the service life can be significantly increased
thereby reducing the future costly maintenance and
associated downtime.

The chimney sections were delivered to the workshop and were abrasive blasted to remove heavy mill scale and to achieve the required cleanliness standard. The sections were then thoroughly cleaned down and vacuumed. Polyglass VEF was then applied using an Agmec internal
pipe sprayer to ensure the desired DFT was achieved along the full internal length. Polyglas VEF is excellent in environments where superior resistance to chemical attack is immersed and non-immersed conditions is required, across the full pH range.

After suitable curing, thickness and spark testing was carried out and final visual inspection made to ensure the quality of the coating work completed. The chimney pieces were then prepared for dispatch to the customer for installation, corrosion protected for an extensive service life. 

Polyglass VEF
Plasmet ZF
Corrothane AP1