An overheated incinerator at Tembec’s Skookumchuck pulp mill resulted in an unpleasant odour pervading the Upper Columbia Valley late last week.
An incinerator at the mill that burns noncondensable gases shut down automatically, as it’s supposed to, when the temperature of the gases its burns crept above 300 degrees Fahrenheit (148 Celsius), resulting in the gases venting (a standard safety measure) for 11 minutes on the night of Thursday, January 8th before the incinerator was restarted. A wind blowing from the southeast at the time meant the gases left a lingering smell in Canal Flats, Invermere, Panorama and other parts of the valley on the morning of Friday, January 9th.
“We do apologize for the odour, it’s really difficult to avoid at times,” said Tembec acting technical manager Roger Puar.
The high temperature triggered an alarm that shut down the incinerator at 10:12 p.m. on Thursday night. The machine was relit and running again by 10:23 p.m.
An incident such as this is considered fairly minor, although as a matter of course Tembec will be investigating it thoroughly, said Puar, adding that the automatic shut down and venting system is in place because if the gas was not vented in such as case, pressure in the incinerator would build up and the mill would have a much more serious incident on its hands.
The smell present in the valley may have been more apparent that normal because the gas normally heads out a vent that runs along one of the mills stacks, several hundred feet (more than 100 metres) high.
“Unfortunately in this incident that vent was plugged by winter condensation,” said Puar. That resulted in the temperature of the vent rising to the point that another automatic safety system kicked in, and the gases was then vented out vents that were only 30 feet (nine metres) above the ground.
The much lower altitude of the vents, combined with the wind blowing in right direction lead to the smell in the valley the next morning.
“Its appears the wind was coming from the southeast at the time of the incident, so it would be blowing in the direction (of Invermere),” said Puar.
The incident was immediately logged in the company’s I-sight database, a monitoring system that measures all incidents relating to environment, safety or product quality, and this automatically results in an internal investigation, according to Puar.
A significant portion of the gases released were methanol, although there were smaller amounts of sulphur compounds.