At the Zellstoff Celgar pulp mill, most things are super sized — even downtime.
On a recent tour the Castlegar news noted the Celgar site, an operation of the Mercer International Group, is filling up with trailers, vehicles, equipment, machinery and about 500 additional people for the annual shutdown; a massive undertaking that will officially start Monday, April 29 and run until Wednesday, May 8.
The contractors will perform specialized tasks needed to ensure the almost 180-page shutdown plan for the Northern Bleached Softwood Kraft pulp mill stays on track.
Douglas Sayer, engineering and technical manager at Celgar, said 28 different contractors — including locals and those hired from across the country — will be working on the site during the shutdown.
Hotels, restaurants and other businesses will no doubt notice a boost in profits with the arrival of the workers. Celgar is one of the largest employers in the region and celebrated it’s 50-year anniversary in 2011.
For those who have been curious about the Castlegar water supply being down from 9 p.m. Wednesday, May 1 until 5 a.m. Thursday, May 2, here’s the lowdown.
First, it’s important to note the water supply will not be affected but the city is asking citizens to limit water consumption to essential use only during this time. Some loss of water pressure and discolouration during and after these times may occur and If discolouration persists after running the water for 15 minutes, call (250) 365-5979 or (250) 365-7227.
Starting on Saturday, April 27 at 9:30 p.m., wood chips will stop being sent to the digester and an enormous sequence of carefully planned events will get underway.
The digester is one of the biggest structures on the Celgar site: almost 61 metres (200 feet) high and with a diameter of about 9 metres (29 feet). It can hold approximately three million litres of chips and chemicals and has been identified as the “critical path” job that sets the schedule for all of the other jobs during the shutdown.
Though the digester is the biggest job by virtue of the time it will take to inspect it and make any repairs, it’s but one of five major jobs (and a number of smaller ones) that will be undertaken until the mill gets back to full operation, projected to be at 4:30 p.m. on Wednesday, May 8.
A recovery boiler, lime kiln, acid sewer line and precipitator will also be inspected and any necessary repairs made. These are not small pieces of equipment. A single passenger car sized section of corrosion resistant, reinforced plastic pipe for the acid sewer line was estimated to be around $30,000, according to Sayer.
Heat from the overhead lime kiln can be felt while under it and it’s about two stories overhead. Replacement of refractors inside it and bearings that help keep it rotating is another big job. The rollers are around 23 tonnes each.
In a handout, Celgar notes the total maintenance costs of an outage of this length are about $12 million, which does not include the revenue lost because they are not producing pulp or power. In addition, chips don’t stop arriving during this time and space for them, as well as items being replaced, is at a premium.
Minimizing the risk to workers and the environment while keeping things on schedule takes a concerted, organized effort.
“Safety is huge,” said Sayer. “It’s a minute step from a minor injury to a major one.”
Fiona Mackay, environment manager agreed and said management has a program in place to identify near-miss situations.
“We encourage everyone to file those kinds of reports so we can learn from them,” she said.
Mackay also said there have been significant changes to the facility over the years with respect to environmental responsibility.
What waste water there is from the plant is already non-toxic before being mixed with two-thirds clean water before being released. Even the temperature of the discharge is monitored for potential impact on fish. Mackay said a recent study showed no impacts downstream at all.
After a series of multi-million dollar investments, Celgar now boasts many “closed-loop” systems that ensure efficiency. A huge, Tokyo-built condensing turbine helps generate more power than needed to operate the mill, with the rest being sold back to the grid.
At the start of the generation process, temperatures are over 450 degrees celsius. By the time the process ends, those temperatures have come down to about 70 degrees. Total power generation is about 70 megawatts per hour (MWh) but the mill needs only about 42 MWh to operate.
Mackay said the system is certified as green power as the hog fuel that powers the generator comes from wood waste analyzed as renewable.
Computerized monitoring stations throughout the site detect small changes in the efficiency of the operation and can be adjusted remotely in many cases.
Last year, a unusual release of ash caused by a procedural error after the shutdown caused some concern for some residents; something not anticipated this year.