A team win at Leland Olds Station maintains emissions compliance

At Basin Electric, protecting the environment is a core value and maintaining emissions compliance is a critical part of doing so. Teamwork is also a cooperative value and means working together to provide safe, reliable, and affordable electricity to our members. 

For the team at Leland Olds Station, located near Stanton, North Dakota, a plugged hopper-bottom silo sent them into action on the night of Jan. 23. 

Leland Olds uses urea, a dry granular fertilizer, to reduce nitrogen oxide (NO_x) emissions and keep them below allowable limits. The urea is received into a large hopper-bottom silo and run through a solutionizing process to make a liquid, which is then injected into certain areas of the boiler fireboxes to help lower NO_x. The station can run for short periods without the injections, but without it, NO_x emissions would climb above set limits. 

“An issue arose when the bottom of the silo ‘bridged over,’ became plugged, and stopped feeding the urea,” Stan Burling, shift supervisor at Leland Olds, says. “Bill Wilson is the scrubber operator on ‘D’ crew, and he controls and monitors the urea system from the control room. Bill noticed the feed rate of the urea drop to zero, and had Kori Link, the equipment attendant on ‘D’ crew, check the system (the urea equipment is her responsibility).”

Link saw that the lower part of the silo going into the auger, called the throat, was plugged. There is no real access to the inside of the silo while it has urea in it except a small hatch on its top. Nick Gerding, Leland Olds boiler attendant, was on the “D” crew assigned to the scrubber that night, and he offered to help work on the issue.

Safety is always a top priority, and in this instance the team took the external stairs to the top of the silo, which are enclosed in railing and toeboard; no harnesses were necessary.

“Kori, Nick, and I took 40 feet of conduit to the top of the silo and rodded down through the urea in an attempt to break through the blockage near the bottom of the silo, which is approximately 50 feet tall,” Burling says. “We then worked at loosening the material in the throat area at the base of the silo with a couple large hammers and partially cycling a manual gate a few times. After about an hour and a half, Bill called us and reported that he had a normal feed rate restored.”

The total time it took to unplug the silo was about an hour and a half. The team also caught a break in the January weather that night, which was very mild, as the top of the silo is outside.