Calcasieu refinery completes total retrofit in six weeks with FOUNDATION fieldbus and Emerson's PlantWeb architecture
Calcasieu Refining Company has upgraded virtually all of the controls at its 22,000-barrels-per-day petroleum refinery here from 25-year-old pneumatics and relay logic to the latest generation of process control technology: open field-based automation using FOUNDATION fieldbus and PlantWeb architecture from Emerson Process Management. This is believed to be the world's first refinery controlled entirely by bus-connected intelligent (microprocessor-based) field instruments. The automation system embraces two atmospheric crude distillation units, a naphtha stabilizer, an 800,000-barrel tank farm, and a five-mile product pipeline.
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The retrofit was accomplished much more quickly, smoothly, and economically than conventional DCS or PLC architecture could have achieved…an estimated 75% time savings by the customer. "I had a contractor tell me this installation would take at least six months with an ordinary DCS, having to hard-wire all the analog instruments," said Jody Verret, process and mechanical superintendent at Calcasieu. "PlantWeb let us do it in about six weeks instead."
A 5,000-barrel-per-day crude unit was added when the retrofit was made and is on-line without requiring additional operators. Costs for operation and maintenance have proven substantially lower, and operating capacity has increased, yielding an expected annual return on the order of 80% of the million-dollar automation investment.
Verret attributed most of this speed to FOUNDATION fieldbus wiring and virtually automatic commissioning of intelligent instruments and control valves. He commented, "We had one worker on the console and one in the field with a radio, running cable and calibrating and commissioning instruments over the network -- nearly as fast as the field guy could plug them in."
FOUNDATION fieldbus allows a single twisted-pair cable called a segment to carry digital communication and power for as many as 16 intelligent field instruments and control valves (e.g., Rosemount pressure and temperature transmitters, magnetic flowmeters, and vortex flowmeters; Micro Motion Coriolis flowmeters; Fisher valves and Fisher FIELDVUE digital valve controllers; and Rosemount Analytical analyzers.) Because of "nonincendive circuit" wiring methods in this Division 2 (normally nonhazardous) area, no conduits or intrinsic safety barriers were required.
"Every instrument that could be fieldbus is fieldbus," asserted Rob Wood, senior engineer at John H. Carter Company, the Emerson representative that provided the initial system configuration, integration, field processor enclosures, and main operator console. More specifically, the job involved 22 FOUNDATION fieldbus segments carrying 116 intelligent instruments. The project also integrated additional new and legacy subsystems consisting of HART and conventional instrumentation, a Modbus network of intelligent tank gages, and a radio link to two RTUs (remote terminal units).
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The main key to this implementation of PlantWeb architecture was Emerson's DeltaV digital automation system. FOUNDATION fieldbus segments radiate from field-mounted controllers that communicate by TCP/IP Internet protocol on a dual redundant optical-fiber Ethernet LAN. The LAN extends to several operator and engineering stations consisting of standard PCs running Windows NT. Software includes Emerson's AMS (Asset Management Solutions) for remote instrument configuration, calibration, diagnostics, and preventive maintenance. The resulting architecture actually represents the next step in the advance of process automation -- a totally digital, scalable network that makes the most of computer intelligence in field instruments, using industry-standard operating systems and protocols and modular software.
That software is attuned to ordinary plant operators, engineers, and technicians. "Our DeltaV system was put in by our own people, with just one session of training. We can implement any additions to it ourselves," said plant engineer Toni Bennett. "It was amazing to me, that it's that easy."
Jody Verret agreed, "I never used computer controls before, and I was worried that it wasn't going to work. Now, you know what our biggest problem is? We're learning that PlantWeb has more and more and more, and we just can't put all of it to work fast enough."
"This is beyond our dreams," Ms. Bennett concluded. "We thought it would work well, we hoped it would, our jobs depended on it working well, and we're very pleased to say our owners love.
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