After six years, the effluent coolers at the Nexen Long Lake Upgrader needed attention to their gasifier coils. This relatively young plant in Fort McMurray, Alberta, uses a unique technology to run its operations: gasification units that instead of using expensive natural gas convert asphaltene into inexpensive syngas—a fuel gas mixture produced by heating the gasifier coils. The high temperature combustion required for these processes had led to erosion in the coils, making repairs necessary. In the early stages, erosion can be repaired section by section, but this time, the project team and Nexen partnered up to replace the entire coil.
New coil and lifting frame being hoisted to its new
home in Train 2.
Aerial view of the Long Lake site, looking north.
There are three distinct client benefits to changing out the gasifier coils: cost savings, new opportunities for investigative work in surrounding elements, and a long lifespan between future shutdowns. “Using syngas at the refineries is still new, but it will likely be the norm in the future,” said Melloy project superintendent Colin Harbarenko. “The plant maintenance that is required when using syngas offered us an opportunity to find a solution that best met client needs and for Melloy to demonstrate our commitment to modern best practices for all of our projects.” to demonstrate our commitment to modern best practices for all of our projects.”
Despite a longer shutdown and an upfront cost, changing the coils is a cost saver in the long run. Replacing instead of patching means infrequent shutdowns for repairs, which means increased output capacity in the competitive oil and gas industry. Melloy’s firsthand experience with this precise change-out process means efficient work completed at the highest level of expertise.
Changing out the entire coil made it possible for Nexen to complete additional investigative work during the effluent cooler shutdown. The project team’s experienced pipefitters were called in to change out numerous valves, including pressure safety valves, and piping systems that enabled Nexen’s quality assurance group to carry out regulatory inspections. Getting it all done at once gives clients the confidence that everything is in working order and performing at the same high level.
The new coil has a lifespan of five to six years, and repair shutdowns are minimized in the interim. “The benefit to these units running smoothly is the plant is not reliant on expensive natural gas. When the gasifiers are running, the plant is completely self-sufficient,” said Harbarenko.
The first change-out was so successful that Melloy completed two more for Nexen in 2014, with another planned for 2015.