Skeels Electric Co., Bismarck, N.D., was the electrical contractor for the replacement of an oil refinery power station cooling tower and related work at the facility’s power station unit in Mandan, N.D.
The refinery opened in 1954 and today has a capacity of 74,000 barrels per day. It primarily processes sweet, low-sulfur, crude oil from North Dakota, and it manufactures gasoline, diesel fuel, jet fuel, heavy fuel oil and liquefied petroleum gas, said Drew Flurer, Skeels’ vice president. The existing tower was replaced due to age, and the upgrade was necessary for the increased cooling water capacity needed for another upcoming project.
“[The] scope of the work replaced the existing south cooling tower, including fans, gear boxes and motors,” Flurer said. “To support the new cooling tower, the electrical infrastructure required a new power distribution center [PDC] and remote instrument enclosure [RIE], which houses the distribution control system and communication cabinets.”
A temporary cooling tower was set up and operated during construction.
“We always plan a fully integrated project to provide cost and scheduling benefits,” Flurer said.
Although Skeels frequently employs prefabrication on projects, the company did not use it for the cooling tower work, Flurer said.
“Due to the nonrepetitive nature of the project and unknowns with the construction and erecting of the new cooling tower, no prefabrication was implemented,” he said. “However, we have mobile work platforms, which allow us to easily move material from a project fabrication area to the desired location. Built on 20-foot platform trailers, they are equipped with welder/generator, electric bender, rigid threader, tool storage, and working areas with chain vises, conduit bend check area and material storage.”
PDC building work included concrete wall penetration, cable tray installation, conduit, cable pulls and cable terminations.
Flurer said Skeels installed and terminated power feeds for two coagulator sludge pumps and two rotary valves. The company installed and terminated cabling for the circulating water pump and firewater pump in the south pump house.
Skeels Electric also installed the clarified water pump in the pump house, installed the firewater pump in the south pump house, installed and refed a safety shower, and refed an overhead crane and lift.
“We coordinated outages and cutover timing and durations with refinery operations,” Flurer said. “We made installation of lighting junction boxes and disconnected old lighting and power panel boards, installed permanent lighting and made terminations.”
Skeels’ crews installed and terminated the power feed from the south cooling tower fan drives, gear box heaters and new lighting transformer and panel boards. They also completed the installation and terminations of power feeds from the water sample shelter heater, commissioned and performed troubleshooting for the variable frequency drive systems and installed the remaining cable trays, conduit and support systems.
South cooling tower
“For the cooling tower itself, work included energy isolation and lockout of power and demo of existing cables and conduits prior to the old cooling tower demolition,” Flurer said. “We installed fan vibration junction boxes and internal components, conduit, cable pulls, landing cables in the fan vibration junction boxes, and commissioning support. We also provided temporary power for the cooling tower contractor including 220-volt [V] receptacles and 110V receptacles every 50 feet along the west side of the cooling tower.
“Other areas of work were instrumentation cable installations from the existing junction box to a safety shower using existing conduit, coagulator electrical service and instrumentation replacement of the lighting and panel boards, installed, de-energized and decommissioned power to the temporary cooling tower, and electric heat trace, electrical installation, and commissioning of El Paso Sampler Building.”
Construction began in July 2017 and was completed in October 2018. Skeels brought in the project 21% under budget.
“Twenty thousand man-hours were worked with zero accidents or injuries,” Flurer said. “We have a work, health and safety policy in place, and before a project begins, job-specific hazards are identified, and a strategy is provided to diminish any risks that may be present. This approach changes with the continual change of project conditions. Before work can begin each day, a job hazard analysis is completed to make sure crews are aware of potential safety issues and to audit the project work area to mitigate any potential risks.”
Established in 1914, Skeels Electric is a fourth-generation, family-owned company that is a regional leader in providing and installing medium-voltage, low-voltage, instrumentation and communications systems for industrial projects, including refining, pipeline, power plant and manufacturing clients.