Stoccaggi Gas Italia S.p.A. (Stogit) is an Italian company that operates Italy’s natural gas storage activities. Stogit was established by the national ENI group in 2000 to manage Italy’s storage business line including storage concessions, gas in the related reservoirs, surface and underground systems and the compression stations needed for storage activities.
Sergnano, near Milan, Italy is the location of one of the Stogit’s eight storage fields. The storage / withdrawal compression duty is achieved by a single Rolls-Royce RB211DLE/ RCB gas turbine-compressor set. As the gas turbine approached its scheduled overhaul, Stogit took the opportunity to upgrade the gas generator, power turbine and the control systems for the entire compression package. With the upgrade, Stogit gained additional horsepower and a state of the art control system offering improved reliability with improved operability.
The original Rolls-Royce En-Tronics® FT-100 control system was based on proprietary hardware and software that had become obsolete. Rolls-Royce was awarded the upgrade by Saipem (EPC contractor) and Stogit who nominated Rolls-Royce to design and supply the controls upgrade. A further challenge was a requirement by Stogit to retain the existing Unit Control Panel, with the new system having to be carefully designed to fit within the existing panel.
Working closely with Rolls-Royce, UCG’s design utilized multiple Allen-Bradley ControlLogix processors with Controlnet Flex I/O. The complexity to the RB211 DLE controls necessitated the use of L61and a L63 processors, each in 7 slot chassis. The ArcNet communication within the panel was upgraded to Ethernet and ControlNet, along with a ProSoft communications modules to interface with the plant DCS. Vibration monitoring was upgraded to a Bentley-Nevada 3500 with integration into the ControlLogix processor.
The new hardware layout was mounted to sub-plates which were carefully designed to replace the existing En-Tronics® FT-100 hardware with minimal effort. Field wiring was marshaled to termination blocks then wired to Flex I/O communicating via redundant ControlNet to the processors.
The new FT-210 HMI, an Allen-Bradley Industrial PC with 19” touch screen operating Wonderware, replaced the existing system. A new front swing door replaced the existing door to accommodate the PanelView and new fold out keyboard.
UCG software engineers migrated the proven logic and algorithms from the obsolete proprietary CBOS using RSLogix5000. The hardware and software subsystems were integrated in UCG’s shop and were fully tested during a 3-day witnessed factory acceptance test.
UCG enabled the success of the project by providing installation and commissioning support. The unit is in service and assists in meeting the needs of reliable gas storage for northern Italy.