In order to process pulp, paper mills recover vital chemicals by burning black liquor in chemical recovery boilers. By combusting black liquor, the recovery boilers generate steam that’s led into a turbine, producing electricity.

Since smelt accumulates on recovery boilers’ floors, a water wall leak could result in a violent explosion if it comes into contact with the smelt bed. To prevent this, Gecko takes a multi-faceted approach.

For composite and overlaid lower furnace tubes, Gecko determines composite thickness and base metal thickness, while for carbon steel tubes, inspectors check for overall metal thickness. This helps our inspectors determine overall wear patterns throughout the furnace.

Additionally, inspectors check critical air ports and liquor nozzles due to the high probability of corrosion in those areas. This includes bent waterwall tubes around these openings.

Inspectors also check recovery boilers for under deposit corrosion (UDC) and other waterside damage, which causes pitting inside crucial water tubes. Pitting does not appear visually from the outside, making traditional inspection a needle in the haystack search.

Gecko’s Robots allow our inspectors to survey and pinpoint all under deposit corrosion in recovery boilers before leaks or explosions happen.