Emerson Exchange 365

The three sets of coke drums at Suncor Energy’s Fort McMurray Upgrading Millennium Complex in northern Alberta, Canada, operate faster than any facilities of their size in the world.  They heat bitumen mined from oil sands up to 925 degrees Fahrenheit, separate out light hydrocarbons that can be further refined, and collect the residual solid coke inside 127-foot-tall drums.  The cooled coke is then cut with thousands of gallons of super high-pressure water and removed from the drums by the ton.  Every ten and a half hours the process starts all over again and continues day in and day out, year round.

With any process that intensive, things can—and sometimes do—go wrong.  In October, 2007, a significant incident shut down one of the coker units, costing Suncor $30 million in lost production.  An internal review identified the root cause as a misaligned isolation valve, and recommended that new safety measures be implemented in all the units.

This week at the 2014 Emerson Global Users Exchange Americas, Nilesh Desai and Shawn Boser of Suncor and Brent Block and Ryan McKimmie of Spartan Controls will describe how they tackled this project, and conquered the problem of unplanned downtime along with it.

From the outset, they knew the task at hand wasn’t going to be easy.

“First of all, the process itself is a challenge,” explains Desai.  “Coke, asphaltines and other solids can migrate into spaces inside valves and cause closure problems.  Meanwhile, valve actuators are exposed to extremely high temperatures and intense vibration that can damage the electronics inside actuator control modules.” 

In light of the potential danger these severe conditions also pose to maintenance crews, Suncor teamed up with Emerson, who makes the actuators, to come up with a unique two-part solution to the problem.

The first part involved removing as many components as possible from the valve actuators and mounting them in separate control modules away from high-temperature and high-vibration areas.  “We mounted these separate control modules (SCM’s) close enough to observe the valve operation but far enough away to avoid the extreme heat and vibration encountered in such areas as the drain valves at the bottom, or ejector valves at the top of a coke drum,” says Boser.

The second part of the solution called for Emerson specialists to install new EIM^TM actuator control modules with interlocks, which allow operators to freeze or isolate malfunctioning valves with the press of a button.  “Potentiometers were added to the actuators’ circuitry to give operators a reading on how far open or closed a given valve is, as well as the percentage of allowable torque being applied,” Block says.  “Read-only displays were also installed in key locations inside the coker units to improve situational awareness and help prevent accidents.”

“The results of the project have been nothing short of dramatic,” McKimmie concludes.  “The rate of actuator failures at our most troublesome coker unit fell from 47 over five years down to zero since the upgrade was completed in the fall of 2012.  More importantly—in addition to the reduced maintenance costs, improved reliability, and increased uptime—Suncor’s operators and maintenance personnel are out of the line of fire.  That, of course, is priceless.”