An annual major maintenance shutdown at Zellstoff Celgar will start Saturday at 6:30 p.m.
According to a statement issued by the pulp mill, the critical job for this shutdown is the inspection and repair of the recovery boiler, which recovers spent cooking liquor and converts it to green liquor which is in turn converted into white liquor by the addition of lime, and returned to the fibre cooking cycle.
It takes approximately 36 hours to shut down the mill so the majority of maintenance in most areas will officially begin on Monday. Some areas, like the recovery boiler, can take up to 60 hours to be taken offline and the maintenance work there will not begin until Tuesday.
Once the work in all areas has been completed, the mill will begin start-up procedures using detailed safety and operational check sheets. It generally takes about 1.5 days to bring the mill back up to full running rates. The expected date to begin startup is March 23.
The annual shutdown is required to allow the company to inspect major pieces of production equipment and repair any deficiencies to help ensure the mill is in good order to run reliably for the next year. A lot of the work is preventative, much like doing regular maintenance on our vehicles.
Other maintenance include digester equipment inspection and repair and lime kiln refractory replacement.
One of several capital projects to be completed during the shutdown is the replacement of the motor speed controls on one of the two pulp machines.
The current drive line up is 22 years old and like other electronics has become outdated and difficult to service. The advanced technology of the new drive system should allow for better control of the rolls as the sheet progresses at variable speeds through the stages of formation, drying and baling.
The shutdown is an expensive undertaking. Total maintenance costs for this outage are approximately $10 million, not including the capital investments or revenue lost while the mill is not producing pulp or power.
The nature of the pulping process requires corrosion resistant materials that are often expensive. Specialized parts and equipment are purchased for the shutdown. To access many areas of the mill, elaborate scaffolds have to be constructed.
There is also the expense of additional contractors and equipment specialists brought in from across the continent.
Additionally, Celgar uses this opportunity to inspect and repair environmental control equipment including precipitators and effluent treatment systems.
The company said it takes “a great deal of care and time while taking the mill down and starting back up to prevent odour or upsets.” However, this can sometimes occur depending on atmospheric conditions during certain stages of the process and would be temporary.
The shutdown benefits not only Celgar but boosts tourism as well. At the peak of the shutdown, there will be approximately 500 additional people on site.
Most of these people will be staying in local hotels and eating in local restaurants.
In an attempt to stimulate the local economy, a significant amount of material and services will be procured from local businesses and contractors as well.