Some of the biggest ductworks you're ever going to see crawled across southeastern Saskatchewan side roads last week on their way to Boundary Dam Power Station. Power wires needed to be lifted along the delivery routes as the slow moving semi-trailers carrying the multi-tonned equipment moved across the snow-drifted prairies.
The three duct monsters fabricated by SaskArc Industries Inc. of Oxbow consisted of the main duct for flue gas casing, along with the inlet and outlet pieces. The casing was put into place in the early part of the week after arriving on Monday. The 90-ton unit required two 150-ton cranes to lift it into place. The duct work inlet and outlet followed in mid-week.
Steve Lodge, an engineer contracted by Stantec and seconded to SaskPower for the installation, said the work had to be planned around weather conditions since they were unable to move the huge pieces after winds reached certain velocities which was the case for several hours last Wednesday and Thursday.
Lodge said there was a design side and power side to the project and he was involved on the SaskPower side of the equation.
“The duct work sits adjacent to the stripper tower. It brings the flue gas temperature down to required values so that it can be entered into the stripper operation,” he said.
"Flue gas comes out of the back of the plant (Unit No. 3) and some of the steam goes to the cooler and it knocks the temperature down about 100 degrees F so the material will be compatible with the stripper media. Then the heat is reclaimed and will be used for other purposes,” Lodge added.
The engineer said the lifting and placing of the duct casing and outlet and inlet will go on over the next several days, dependent on wind and other weather conditions. Assembly is done with the assistance of the large construction cranes on site.
“These units perform an important task in the flue gas cooler assembly so there will be no compromising in terms of correctness or safety or any other element of installation,” Lodge said, noting that at certain times, the pieces will be hoisted into the air and aligned while they are in that position, thus the need to have slower wind conditions.
The duct work is all part of the SaskPower clean coal initiative which is a $1.24 billion project that will see about 90 per cent of the noxious substances, including carbon dioxide, captured from the newly rebuilt Unit 3 unit. Upon completion in 2014, Unit 3 will provide approximately 110 megawatts of electrical power for the SaskPower grid.
It will be the first commercial sized carbon capture unit in the world.
The captured carbon dioxide gases will be used for enhanced oil recovery projects in southeast Saskatchewan or, if necessary, sequestered underground until required.
SaskPower announced recently that they signed an agreement with Cenovus Energy Inc., which will see the oil producer use the CO2 for their oil recovery operations in their major oil field operations near Goodwater.