Due to its production of steel, Carsid produces blast furnace gas. This gas is burnt in a boiler under high pressure and at a high temperature (125 bar/560°C) in combination with naphta and natural gas. The steam produced in this way is used to generate electricity with a high/medium and condensing steam turbine. The total production is approximately 40 MWe. The boiler is an existing boiler, built in 1965, and has not been used in the last 25 years. The reconditioned turbine comes from another Carsid site. Powerspex has been asked to renew the entire I&C system. The local instruments must be partly reused, and the control and safety system are based on the PLC technology of Siemens S7. The operating and monitoring system must also be renewed based on the SCADA system of Siemens, of the type WINCC.
This was a large assignment for Powerspex. The process technology is more complicated due to the high pressure and temperature, the blast furnace gas, the combination of the forced and induced pull of the fans, the starting procedure via HP and LP steam bypass stations and the condensation system with 3 pre-heaters. Replacing the technology is complicated because of the reuse of a boiler, which has been out of use for the last 25 years, in combination with a reconditioned turbine. The I&C system is complex because of the functional specifications to be drawn up by Powerspex. The PLC technology and SCADA system have been expanded (approx. 1,000 markings). And, last but not least, the timetable is very tight.
In addition to the technical challenge, Powerspex is also faced with complex communications. The main language is English (contractually the formal language), but French (the local language), Dutch and Italian are also spoken.
Carsid is owned by Duferco (an Italian steel cooperative) and the people on site will be assisted by Group-IPS. Close cooperation with the main suppliers, such as Siemens Netherlands, is also essential.
Specifications of the functional design, control narratives, cause & effect diagrams
Software (S7 and WINCC), HCAD, E-Plan
Site management, project management, steam turbine.
The revision was completed within 5 months and the power plant is functioning well.