HART Helps Keep the Heat On
When winter strikes, you need heat to beat back the cold, and it’s best when the fuel is reliable, plentiful, and relatively clean burning. This year, consumers in the U.K. have a new source for that heat, natural gas and condensate pumped across the ocean from Norway’s undersea Ormen Lange gas field. They’ll warm water for tea, cook food, heat homes, generate power and otherwise use this fuel for years to come.
They’re able to do so, in part, because of HART technology. Erling Ramberg is an automation lead engineer at the Norwegian oil company StatoilHydro. The firm designed the onshore processing facility that produces natural gas and condensate shipped to the U.K. He notes that the goal was to be as efficient as possible and that HART-capable transmitters and valves were chosen for this and other factors.
“It has to do with size of the plant, of course, and the location out on the island. Also, we do not want to bring in more people than required,” he says.
Because of the ways it has applied the advanced capabilities of HART technology, the Ormen Lange onshore facility has been named 2007 HART Plant of the Year. This international award is presented to end user companies in recognition of their ingenuity in applying HART technology. Recipients are plants that have taken the capabilities of HART instruments beyond configuration and calibration or are using the real-time diagnostics and process variables of HART-enabled devices to improve operations, lower costs and increase plant availability.
“This plant was selected for its foresight and ability to build the infrastructure to take advantage of HART capabilities in their intelligent field devices,” says Ron Helson, executive director of the HART Communication Foundation. “They’re very forward thinking and proactive when it comes to moving to a predictive maintenance strategy that will lower maintenance costs and improve plant reliability.”
Up from the cold, dark sea
Discovered a decade ago by one of StatoilHydro’s parent companies, Ormen Lange is a natural gas field off the Norwegian coast. It’s large in more ways than one. It measures 40 km long and eight km wide. It has proven gas reserves totaling nearly 400 billion cubic meters, an amount capable of supplying up to 20% of the U.K.’s natural gas needs for the next forty years.
But Ormen Lange is not easy to exploit. The gas field itself lies roughly 3,000 m below sea level, buried beneath an uneven seabed and sitting under 800 to 1,100 m of water. Situated 120 km off the coast of Norway, the site experiences some extreme natural conditions. There are subzero temperatures, whether measured in Fahrenheit or Celsius, most of the year. The seas are stormy, with strong underwater currents.
Five companies are partners in the project that brought this fuel up from the bottom of the sea and into British homes: StatoilHydro, Shell, ExxonMobil, Petoro, and Dong. No one partner owns more than a third of the project, with StatoilHydro in charge of development and Shell operating the onshore processing facility.
As for project itself, it consists of 24 subsea wells in four seabed templates. The output of the wells is sent in pipes 120 km to Nyhamna on the island of Aukra on the west coast of Norway. There the fuel is processed and readied for shipment to the U.K. via a 1,200 km long undersea pipeline.
Ramberg notes that direct pumping of the fuel to shore-based processing won’t be problematic because monoethylene glycol (MEG) is added from an on-shore plant to keep the liquid flowing at all times. “We pump the MEG liquid out to the wells, inject it in the pipelines and transport it with the gas to shore to prevent freezing.” Once onshore, the MEG is removed and reused. The fuel then has to be processed and readied for shipment to the U.K.
Meeting the challenge for less
When designing the plant, StatoilHydro faced several constraints. One was the remote location, second was the occasional harsh weather, and a third was the size of the facility. As finally built, the on-shore plant is one square km, with a main control room and 10 substations. “This plant is quite large,” says Ramberg.
An overriding concern in the design was the need for absolutely reliable operation. No one, after all, wanted a consumer in the U.K. to turn on a burner and get nothing out because of a problem with a plant across the sea. The company, quite naturally, also wanted to accomplish all of its goals efficiently and with as little onsite personnel as possible.
Ramberg recalls the technology selection process. The designers knew that given the constraints, predictive diagnostic functions were particularly important. With that capability, the health of a valve or other component could be gauged and maintenance could be done as needed. Valves wouldn’t be changed out too soon, which would waste money. Nor would they be changed out too late, potentially jeopardizing operations.
There were other benefits to having a wealth of diagnostic information. The right data can identify the root cause of a problem. It might then be possible to correct the issue remotely, meaning fewer personnel would be exposed to harsh weather and possibly dangerous conditions. What’s more, the collection of data could, over time, lead to the elimination of some problems as root causes were identified and fixes implemented.
Because of the advantages of a communication rich approach, the company selected HART Communication technology to deliver the device diagnostic information it was seeking. The finished plant has about 1,400 HART-enabled field devices connected on-line, full time. Of these, about 350 are valve positioners, with most of the rest instrumentation transmitters. A handful of traditional 4-20 mA anti-surge valves are connected to HART multiplexers so that their data can be converted for communication.
Control is handled by an ABB system, with secondary controllers in the substations handling the interface between local devices and the plant-wide controller. As might be expected given the need for reliability, there are redundancies and intelligent approaches built into the setup, which aren’t always those typically thought of or used. For example, there’s a robust video conferencing capability so that experts from around the world can hold virtual meetings to help diagnose problems and propose solutions.
After processing at the plant, the fuel begins a trek to the U.K., traveling 1,200 km before arriving at a terminal at Easington. “It is a very long pipeline. I think it is the longest subsea pipeline so far,” says Ramberg.
He notes that startup of the operation was an activity that took some time, with an eye toward ramping up full production over a span of months. “The startup was an activity going on for weeks, but the actual startup was when they opened the valve to the well. That happened the 13th of September,” he says.
Ramberg adds that HART technology helped the plant meet its commissioning schedule. With that, in many respects, his job is done. Starting in December, operation of the plant was taken over by project partner A/S Norske Shell, the Norwegian member of the Shell family.
Graham Baird, a condition monitoring engineer for A/S Norske Shell, will be one of those responsible for monitoring the plant’s day-to-day operations and health. He’s had input in the design phase, particularly with regard to what’s needed for operational monitoring of intelligent field equipment condition.
While there hasn’t been a lot of operational data so far, what the HART-enabled technology has delivered is promising. Baird cites the control system’s asset optimizing package and device manager. “Early indications are that these will give us a lot of useful actionable data, as they are online systems scanning the HART-enabled instrumentation continuously,” he says.
With alert reporting activated, operators can prioritize, schedule, and track their efforts. Baird notes that troubleshooters have made fault diagnosis very quickly, enabling corrective action to be taken in a controlled manner. Often this has allowed fixes to be made directly to the root cause of the problem rather than a symptom.
There can also be synergies with other non-HART condition monitoring systems. For example, compressor performance can be influenced by surge valve conditions, instrumentation calibration, and so on. With more diagnostic data available, it’s possible to cross reference between systems to establish why equipment may not appear to be performing according to design. “All in all we get a much better overall view of the plant asset condition right now” sums up Baird.
He explains that using HART technology and the wealth of diagnostic information it provides aligns with Shell’s Total Reliability Initiative. Getting a more informative picture helps plant operators rest easier at night, Baird says. “Having a large number of instruments and valves connected to HART-based systems for diagnostics can help us achieve a high availability for safety related instruments, critical process instruments and control valves. This gives plant operators confidence that they have properly operating control equipment.”
Thus, an intelligent application of HART technology helps keep the U.K warm. With the predictive diagnostic capabilities built into the system, the Ormen Lange plant should be able to do so in a cost-effective manner for years to come.
|Hank Hogan is a contributing writer for Control Engineering.|
The HART Plant of the Year is an international award presented annually recognizing innovative use of the HART Field Communications Protocol in real-time industrial process plant applications.
It is the only public award presented to end user companies to reward ingenious applications of HART Communication technology. The award recognizes the people, companies and plant sites around the globe that are using the full capabilities of HART Communication in real-time applications to improve operations, lower costs, and increase plant availability.
Recipients are plants that have taken the capabilities of HART instruments beyond configuration and calibration, or are using the real-time diagnostics and process variables of their HART-enabled devices integrated with their control, information and safety systems.
Previous HART Plant of the Year recipients are BP Canada Energy NGL Operations plant in Ft. Saskatchewan, Alberta, Canada (2006); Sasol Solvents SMG Operations plant in Sasolburg, South Africa (2005); the BP Cooper River plant in Wando, South Carolina, USA, and the Clariant Antioxidants Plant in Gersthofen, Germany (2004); the Detroit Water and Sewerage Dept. in Detroit, Michigan, USA (2003); and the DuPont DeLisle manufacturing facility in Pass Christian, Mississippi, USA (2002).