Emerson automates level measurement at Esso refinery using PlantWeb to deliver installation savings and integration

Rosemount^® transmitters display level and volume locally, plus communicate over FOUNDATION fieldbus to DeltaV™ system and plant network.

Emerson Process Management has replaced independent level measurement equipment for seven spherical propane and butane storage tanks at the Esso refinery at Slagen in Norway, achieving installation savings and integration of the measurement solutions with the refinery network at no extra cost. Emerson supplied PlantWeb digital plant architecture with Rosemount^® 3051S pressure transmitters communicating over FOUNDATION fieldbus networks to a DeltaV™ digital automation system.

	Esso Slagen refinery   High-resolution image

The existing independent level measurement solution, consisting of differential pressure manometers with oil filled capillaries, had been installed in the 1960s and required replacement. Because of the site requirement that the independent level measurement system have a local indicator and be separate from the main level measurement system, Esso evaluated replacement using similar manometer technology, as well as alternatives.

A FOUNDATION fieldbus-based solution was judged as an alternative that could bring cost and functional benefits, and also serve as an ideal test of this new technology. Evaluation led to selection of the Emerson PlantWeb solution that was no more costly than a manometer system because of the unique capabilities of the 3051S transmitters and FOUNDATION fieldbus digital communications.

The DeltaV system with operator console was installed in a local substation. Two transmitters were installed on each vessel, one measuring the top pressure and another bottom pressure. AMS™ Suite: Intelligent Device Manager capability resides within the DeltaV system and is used to configure the transmitters, and to deliver predictive diagnostics from the devices for fast decision making. Because only two fieldbus cabling segments were required for the seven sets of two transmitters, only two cables were required to be run to the storage vessels. This contrasts with the usual fourteen cable runs, saving on installation costs.

The standard FOUNDATION fieldbus function blocks in the 3051S transmitter are used to calculate the difference in pressures between the transmitters located at the top and bottom of the vessels. This technology has removed the need for oil filled capillaries.

The DeltaV system uses the standard FOUNDATION fieldbus function blocks to calculate the volume, and also uses the secondary value temperature reading from the 3051S pressure transmitter to perform a temperature compensation calculation that is applied to the level and volume measurements. Both the volume and level values are sent to the local display on the lower transmitter by utilizing the FOUNDATION fieldbus digital communications. The two measurements alternate on the display, providing the operators with a local indication. This functionality is made possible by the combination of digital communications and the 3051S transmitter's capability to display any of the four values on the segment.

"In addition to the savings in cable and capillary costs, Esso has seen several other benefits," said Rolf Jenssen from the Norway office of Emerson. "The local indication on the transmitters eliminates the need for an explosion-proof DeltaV display to be mounted outdoors; this would have been necessary because, for safety reasons, the operators are not allowed to enter the sub-station where the DeltaV system is installed. The DeltaV system can now be connected to the site network, enabling information to be made available to other areas of the plant. This was previously not possible with the manometer based level measurement."

Emerson provided an on-site training course for the operators and maintenance personnel to familiarize them with the new technology.

About Emerson Process Management

Emerson Process Management (www.emersonprocess.com), an Emerson business, is a leader in helping businesses automate their production, processing and distribution in the chemical, oil and gas, refining, pulp and paper, power, food and beverage, pharmaceutical and other industries. A division of Emerson, Rosemount Inc. (www.emersonprocess.com/rosemount) is a global leader in high-precision pressure, temperature, level, and flow instrumentation. Rosemount's best-in-class technology and expertise play a key role in Emerson's combining of superior products and technology with industry-specific engineering, consulting, project management and maintenance services. Emerson brands include PlantWeb®, Rosemount®, Fisher®, Micro Motion®, Daniel®, DeltaV™, Ovation®, and AMS™ Suite.

About Emerson

St. Louis-based Emerson (www.gotoemerson.com) is a global leader in bringing technology and engineering together to provide innovative solutions to customers in process control; electronics and telecommunications; industrial automation; heating, ventilating and air conditioning; and appliance and tools. Sales in fiscal 2004 were $15.6 billion.

PlantWeb, Rosemount, Fisher, Micro Motion, Daniel, DeltaV, Ovation, and AMS are marks of one of the Emerson Process Management companies. Other marks are the property of their respective owners.