Bespoke Odour Extraction Unit

Although the extraction unit is an existing system used within the pharmaceutical industry, this contractor has adapted the system as a way to aid dismantling and de-gassing of gas holders. The unit can change 50,000 cubic metres of air per hour. It is a sealed unit so no risk of gas escape or ignition.

This has an Activated Carbon Deep Bed Absorber fume control system with a large fan handling up to 50,000 m3/hr of air or 2 air changes per hour. This would also provide an effective capture velocity of 0.7 m/sec across an access opening of 20m2, thus keeping the tank being cleaned under negative pressure.

This is based on the size of the largest gas holder No. 1 having an internal volume of 34,000 m3 once all the water has been removed. Initially 4 No. 1 metre diameter holes will be cut into the crown of the gas holder which will increase the capture velocity across 3 of the holes significantly making the risk of fume escaping negligible.

The fume control system has a particulate prefilter section to remove dirt from the air to protect the carbon beds. Twin Carbon beds inside the absorber would contain 24 m3 or approximately 12 tonnes of specialised impregnated activated carbon providing very effective odour control of the air extracted from the holder. This carbon is designed for general odours as well as being especially effective on mercaptans, hydrogen sulphide and other sulphurous contaminants typically found in waste treatment and also in natural gas additives.

A Zone 2 ATEX rated fan is included due to the possibility of flammable gases being present in the airstream. Ducting supported on and lashed to cantilevered scaffold support, supports the ducting.