Where reliability is paramount, Nynas chooses PlantWeb® architecture with FOUNDATION fieldbus protocol

Austin, Texas (20 August 2001) — Nynas, a Sweden-based specialized oil producer, has selected PlantWeb field-based architecture with FOUNDATION fieldbus digital communications from Emerson Process Management to automate critical control loops at its bitumen refinery in Sweden. The architecture's implementation of fault tolerant redundancy with the fieldbus technology made it ideally suited to meeting the challenges of the project.

Situated in Gothenburg on the Swedish west coast, Nynas relies on steam jacket heating of the main bitumen storage and delivery tanks to keep the product liquid — and able to flow throughout summer and winter. Reliability is of paramount importance on this application, and this led to selection of the most reliable field devices and also to the requirement that redundancy be used for temperature sensing and bus power.

Selection of Emerson's field devices satisfied both the reliability needs and redundant sensing. Baumann 24000S series control valves, fitted with FIELDVUE^® Digital Valve Controllers, were selected to control the steam flow used to maintain the tanks and process lines at the right temperature. These valves are installed on the same FOUNDATION fieldbus segment as the relevant temperature transmitters, which are the dual-sensor Rosemount type 3244MV. The Hot Backup™ feature in this transmitter allows connection of two independent temperature-monitoring elements. If the first, primary temperature sensor element should be detected as having failed, there is a seamless transfer of the 3244MV transmitter output to follow the second element. Measurement is maintained and the bitumen continues to flow, which gives the redundancy and reliability that Nynas was seeking. An alarm message would be transmitted to the operator over the fieldbus link, informing him that one of the sensors is faulty.

For redundant bus power, the field outputs from Emerson's DeltaV™ digital automation system were powered by the Hawke Route-Master dual redundant intrinsically safe fieldbus network power supply and isolated segment couplers. This provides intrinsically safe power for the FOUNDATION fieldbus segment used on the heating control system, in the Gas Group IIB hazardous area around the tanks, and again provides the same dual redundancy approach of having primary and secondary supplies with a seamless transfer between them in the event of a problem.

Nynas found additional benefits in the simple cabling used with the PlantWeb architecture's implementing of FOUNDATION fieldbus. Installation and cabling was easy to understand — and even used pre-existing plant cabling where available. They particularly commented on the reduction in numbers of cables, and the lack of wires now attached to the previously crowded cable trays around the storage tanks.

Following installation of the heating control system, further FOUNDATION fieldbus segments have now been completed. These involve five Micro Motion T-Series straight tube Coriolis meters monitoring heavy oil flows along 50mm lines in the distillation area, and providing signals to five existing control valves fitted with Fisher FIELDVUE Digital Valve Controllers.

Nynas has chosen FOUNDATION fieldbus as their preferred protocol. It meets their expectations, particularly in terms of reliability and operational redundancy within the control system. The interoperability of the FOUNDATION fieldbus is shown by the use with compatible isolators from Hawke, and by incorporating existing control valves into the system after retrofitting the FIELDVUE Digital Valve Controllers.

About Emerson Process Management

Emerson Process Management, an Emerson business, is a leader in helping businesses automate their production, processing and distribution components in the chemical, oil and gas, pulp and paper, power, food and beverage, pharmaceutical and other industries. The company combines superior products and technology with industry-specific engineering, consulting, project management and maintenance services. Its brands include: Fisher; Rosemount; Micro Motion; Daniel; Intellution; Performance Solutions; Westinghouse Process Control; PlantWeb; DeltaV; and AMS.

About Emerson

St. Louis-based Emerson 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 2000 were $15.5 billion.

PlantWeb, DeltaV, and FIELDVUE are marks of Emerson Process Management. FOUNDATION is a mark of the Fieldbus Foundation. All other marks are the property of their respective owners.