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Alyeska looking at modular pump station facilities Electrification of stations, replacement of 42 turbines with fewer than 10 under consideration by trans-Alaska oil pipeline operator Kristen Nelson Petroleum News Editor-in-Chief
Alyeska Pipeline Service Co. has completed the conceptual engineering phase of strategic reconfiguration for the pipeline and is working on preliminary engineering, expected to be completed this year, which will give the company the cost and benefit figures needed for a go-no go decision by the pipeline's owners.
One of the issues Alyeska is addressing, John Barrett, Alyeska's program manager for strategic reconfiguration, told Petroleum News June 19, is how to deal with changing volumes of crude oil. The company has to consider how it would accommodate the change if forecasts of flow rates suddenly went up.
“This project actually makes that easier, because as we put the new facilities in (see part 1 of this story in the July 6 issue of Petroleum News), they're going to be modular and scaleable, which means that if we needed additional pumping horsepower, we would bring in more modules,” Barrett said. If flow rate goes up, you bring in more modules — if it goes down, you shut them down, either leaving them in place or moving them to another location.
Those kinds of future changes wouldn't have the impact that shutting down a pump station has today, Barrett said. “Today, if we shut down a station because the flow rates are going down, it impacts 20 to 25 people at that station. … With the new mode of operation, you wouldn't have that because you wouldn't have people that are tied to pump stations.” New pumps with electric motors The base case being evaluated now is that for pump stations currently in use, “we would put in new pumps with electric motors and these would be in … truckable modules. So that these could be fabricated and delivered to the site, placed on foundations and connected to the pipeline system.”
Pump stations at the northern end of the line are currently powered by natural gas. A line from Prudhoe provides fuel to run those turbines, and Barrett said Alyeska is looking at the possibility of connecting pump station 1 to the power grid at Prudhoe Bay. Turbines on the lower end of the pipeline run on liquid fuel, he said, and Alyeska is evaluating whether to put in turbine generators that run on liquid fuel or tie into a commercial power source, such as Golden Valley, which is a possibility for pump station 9.
There are some 42 turbines running on the pipeline today, Barrett said.
“And when we finish this we will probably have less than 10.”
That will reduce maintenance on the turbines.
Each of the pump stations has several utility systems that have to be operated and maintained, and those are not needed with electric motors and unmanned stations.
And most of the equipment is driven by liquid fuel, “and most of our spills are liquid spills, not crude oil. So the potential for spills goes down as we simplify and upgrade this equipment,” Barrett said. Reducing the number of turbines from 42 to fewer than 10 will significantly reduce air emissions.
“And bottom line is, the environmental benefit is fairly significant, as well as the economic benefit and the efficiency and ease of operation,” Barrett said. Control system upgrade Alyeska's supervisory control and data acquisition system at the control center in Valdez is being upgraded.
Right now, Barrett said, the pipeline is controlled and monitored at Valdez, “but we also have people at every pump station who are doing monitoring and some controlling at the station.”
That monitoring and controlling would all be centralized under the new system that would be installed.
“You really don't need someone to walk around and take readings in this day and age. That can all be done through the computer systems and the communications systems that are there. And it can be displayed, it can be analyzed, alarms can be set so that if something is outside of a range that it automatically tells you what is there and you don't have to worry about someone making the rounds every hour and did something change right after he walked by it?” Barrett said.
Alyeska is designing and getting ready to install a new supervisory control and data acquisition system that will work for the existing system and for the new system, he said. Goal: minimize cost of transportation The goal: “Minimize the cost of transportation of oil,” Barrett said. “The producers are trying to … minimize the cost of producing the oil and we have to minimize the cost of transporting it.”
When companies compare the costs of doing business in different parts of the world, he said, “the overall cost of getting a barrel to market is what people compare.”
Reducing the cost of transportation will encourage investment in Alaska, he said.
“So we want this to be as efficient as possible, but … we will not sacrifice safety or operational integrity and we want to be able to move all the barrels that are produced. Those are guidelines as we go through this final study phase. And I believe that we can come to a solution that will accomplish all of that and provide significant efficiencies for this pipeline system.”
The goal of the reconfiguration, he said, is to move the oil that's there as safely as that oil is moved now, and “to be able to respond in the same way if anything happens.”
Larger scale change Upgrades have been done to the pipeline system over the years, Barrett said, and the supervisory control and data acquisition system has been upgraded before. One of the reasons that system is being upgraded now is because computer technology advances so rapidly that you eventually reach the point where it's easier to buy a new system to take advantage of new technology. That upgrade is “also to take advantage of the new communications systems that we have, the new control systems that we will have on the pipeline system,” he said.
“And all of this works together to give you the end result of a fully automated pipeline system that you can run from one control center with the appropriate level of monitoring, control and response.”
It will be a better system than Alyeska has today, Barrett said, and it is a fairly significant change.
“We're changing some equipment at stations and we're going to make it a much more efficient, easier to operate and maintain, easier to change for future changes to flows, flow rates. Those are the things that we get from this.
“And the lower cost of transportation — the end result is the lower cost of transportation — encourages investment on the North Slope. It makes Alaska more competitive with other parts of the world.”
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