“Borealis’ cracker in Stenungsund, Sweden was a very early adopter of APCfor olefin plants. Already 1982, then owned by Exxon they introduced severity controlfor the furnaces together with selector based furnace constraint control and otherfurnace controllers. All controllers ran in Honeywell’s PMX process computer on top of aTDC2000 DCS.While the constraint control was moved to DMC 1995 the severity control, withimproved regressed models, kept on running in the old system.When Honeywell announced 2001 that support for PMX would cease 2007 a project wasstarted to migrate all process control applications to a new Experion PKS system.It was decided that instead of a translation of the old applications they would becombined in a single DMC for each furnace with severity calculations done by an on-lineSPYRO.While on-line SPYRO was used in RTO since 1996 the then common implementation ofSAPC, SPYRO for APC, would introduce additional software to learn and maintain. Thesolution was to use a copy of the existing RTO model, trimmed down to contain onlyfurnaces and the feed headers and speed it up to execute with the DMC frequency.While this sounds easy there were several challenges that will be described in thepresentation.”
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