Safety System Modernisation Migration with a Vision: How to Update a Whole Refinery in Only Two Weeks
Refinery modernizes safety systems in just two weeks and assures plant availability for the future—In September 2014, the German refinery Heide Refinery used two weeks of planned downtime at its pyrolysis plant to migrate to new safety systems. The technology selection emphasized plant availability and a high level of investment security, while extensive preliminary testing guaranteed a smooth changeover.
Heide Refinery is Germany's northernmost crude processor, converting more than four million tons of oil each year. During an extensive DCS replacement, the site exchanged the 20-year-old safety technology of its pyrolysis plant with new Himax systems from the same manufacturer, Hima Paul Hildebrandt. Plant availability was of major importance: In the pyrolysis plant, process changes or operation conversions are undertaken frequently. These modifications need to happen quickly and easily during operation, without impairing safety.
The Himax safety system is designed for large and medium-sized process applications. All changes, upgrades, maintenance and tests can be done during operation, with extensions being easily possible. Thus, for example, safety-relevant functions of the propylene dryer could be integrated into the control system.
Plant Operators Plan Migration to a Future–Proof Safety System
Heide Refinery wanted a state-of-the-art, future-proof safety platform that can be easily extended. In the pyrolysis plant, three redundant Himax setups are used as ESD, BMS and F&G systems in the compressors, the naphtha and ethane furnaces and other units. A Himatrix F35 connected to a Himax controller via safe ethernet serves as pump controller.
Overall, the safety controllers process ap-proximately 2,000 signals. Integration with the operating and observation level of the previous process control system, a TDC 3000 and the new Experion PKS, both from Honeywell, was achieved via Modbus RTU and Modbus TCP/IP.
It was necessary to retain the existing coupling to the TDC 3000 via Modbus RTU, as signals from the controllers were required for more complex regulating tasks. This made it necessary to integrate the safety system in both control loops. The couplings were extensively tested prior to installation, so that commissioning ran smoothly.