It was a slow and methodical process at the start, but no one seemed to mind as long as all the details were covered. When the big lift began it took less than 20 minutes to complete the "stand-up" of the 250 ton carbon dioxide stripper vessel that will be one of the key components in the $1.24 billion clean coal project at Boundary Dam.
The stripper vessel that measures 70 feet in height and 26 feet in diameter was lifted into place behind Boundary Dam's No. 3 generating unit late Saturday morning. About a dozen employees of SNC Lavalin Inc., the main contractor for the construction and engineering phase of the project, began rigging up for the lift before 9 a.m. with the actual tilting and hoisting taking place around 11:30.
"The big crane has a total lifting capacity of 650 tons, so this is well within its range," said Gary Cooper, construction manager for SNC-Lavalin. He was on-site for the entire process as the blocks and then the saddles that were holding the vessel in a horizontal position since it had been unloaded from a huge flatbed truck unit on Dec. 22 were carefully removed.
Even the arrival of the stripper unit was a significant event since it was loaded on a flatbed with 224 wheels under it that was both pushed (three units) and pulled (one unit) by semi trucks from Tofield, Alberta (near Edmonton) where it had been built, to Estevan, a journey that took four days since they had to travel at reduced speeds with several pilot vehicles and pass through a number of restricted areas and clear a number of power lines, etc., en route.
The carbon dioxide stripper and its sulphur dioxide stripper will work together with two absorbers that are under construction to perform the vital functions that will result in the environmentally friendly unit going into service by 2014.
Absorbers take the carbon dioxide, capture it in an amine solution that is pumped from the absorber to the stripper where the liquid fizzes up, and then releases the carbon dioxide that is captured and stored underground for later use as an enhanced oil recovery agent.
The two cranes that were used for the big lift were brought onto the site just for that singular duty by All Canada Crane. The larger unit arrived in pieces aboard 39 trucks and was assembled on site in eight days. The smaller crane, with a 300 ton capacity, was built in unison with the larger unit.
"The big crane doesn't need to move, it just lifts the top end of the vessel up using trunnions, while the smaller tailing crane pushes the bottom end of the vessel forward toward the pad," said Cooper.
"Removing the cribbing and the two saddles takes some time while the unit is horizontal," he added.
But once the stand-up process started, it didn't take long to get it in place, holding it over the pad as the workers adjusted and tweaked to ensure that when it was put down, it was in the precise spot it needed to be in.
Once in place, the rest of the structural steel work can now proceed. That will have the stripper encased along with the acidizer and other components using metal cladding.
"We have about 100 workers on site right now," said Cooper.
Bob Turczyn, supervisor of construction for SaskPower's engineering services division, the host facility, was also available for the lift. He noted that the estimates were for the lift to be completed that morning which was pretty well the case.
The lift was originally planned for Thursday, Jan. 5, but high winds in the region made it impossible. Another attempt was scheduled for Friday, but it too was delayed due to wind velocity. Cooper explained that any winds over 30 kilometres per hour would jeopardize the crane work since it would make the vessel swing too much, making it nearly impossible to set it down accurately.
But wind conditions were nearly perfect on Saturday with only a light breeze and sunny skies prevailing, which made the work move along smoothly, if not effortlessly.
Cooper, who has been involved in engineered lifts before, has also been SNC-Lavalin's man on the spot for SaskPower related projects in North Battleford (new gas generating station) and Saskatoon (retrofit of the Queen Elizabeth Station). And even though he isn't a native of Saskatchewan, he noted that "I've spent the past four years here and it's been interesting."
Cooper added that work on the BD3 project is moving ahead quickly following some delays last summer due to the flooding which restricted access to the project site and slowed down construction.
"We're about 50 to 60 per cent completed on the structural steel side of the building. We want to have it closed in by spring," Cooper added.
"This is the first of its kind in the world. It's new technology going in here and it's being watched by everybody, especially those in coal-fired power generating worlds," he said in conclusion.
