100% DEDICATED TO INDUSTRY Oil & Gas Bulk Liquid Storage Network Upgrading to a modern overfill-protection safety solution delivers to a UK facility SIL 2 capabilities, tighter integration and a clearer lifecycle roadmap, all while aligning with a bigger upgrade project and plugging into the existing distributed control system
Solutions
A Rockwell Automation solution was installed that included: • Allen-Bradley: o safety controller o POINT Guard I/O o high-end process automation controllers • 1783-NATR (Network Address Translation Router) • EtherNet/IP fibre optic network • Endress+Hauser: o radar level sensors o RMA trip amplifiers Results • Longer and better-supported lifecycle • Tighter integration with existing DCS • Ideal platform from which to expand for upcoming site-wide upgrades • Product synergy, tighter integration and seamless interconnectivity
Solutions
Determining when the time is right to upgrade to new hardware and systems can be a challenge for any industry. The costs of implementing new solutions must but be weighed against the benefits, which can include: • an almost immediately boost in performance, • better communication — in line with Industry 4.0 practices • enhanced safety, thanks to technological advances that address tougher legislation demands. • improved availability and uptime — as products age, spare parts become harder to source, making maintenance tougher. Such a decision to modernise was faced by a UK bulk liquid import and storage terminal when an issue arose with the logic solvers used to govern the plant’s overfill protection system. Although installed in 2011, the units were already facing end-of-life issues. As critical elements of the safety, environmental and wastage system, the organisation knew the units had to be replaced while keeping downtime to a minimum.
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100% DEDICATED TO INDUSTRY Background Overfill protection, mandated by the UK’s Health and Safety Executive, address three areas of concern: • Safety: If a tank becomes overfilled, a vapour cloud can form. Although an unlikely event with safety systems in place, it can be a danger if the cloud somehow gets ignited. • Environmental: Overflowing petrochemical substances could be harmful to local flora and fauna. • Economic: Overfilling is wasteful because it is not profitable to recover the liquid. The terminal primarily handles jet fuel and diesel. It has a total liquid capacity of 300,000+ m3, with individual tank capacities ranging from 500 to 20,000 m3. One jetty accommodates vessels up to 55,000 tonnes deadweight with drafts of up to 12m, and a second handles vessels up to 125,000 tonnes deadweight with drafts of up to 14m. The site was fully rebuilt in 2011, addressing all current standards and practices. High-level, SIL-rated logic solvers were deployed, but recently they became difficult to support. In addition to replacing to ensure the necessary safety capabilities, any solution had to consider the plan to add storage tanks at the site, while also seamlessly plugging into the site’s existing distributed control system (DCS). Solution The decision was to go with SIL 2-capable programmable automation and process safety controllers, with a fibre optic EtherNet/IP network and safety I/O modules providing the data paths. The objective was to provide an upgrade path that would deliver seamless integration with the existing systems. A new control cabinet, housing the replacement safety system, was provided to interface with the existing equipment and field terminals. This allowed the replacement safety system to be put in place before impinging on the existing controls, minimising downtime during changeover. The SIS uses an Ethernet communications network arranged in a Device Level Ring (DLR) configuration, providing enhanced local network fault tolerance and improved system availability. The DLR format reduces the I/O count and the amount of field wiring, as safety signals communicate via the CIP-Safety Protocol over EtherNet/IP. To aid segregating the SIS and DCS, the local
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DLR network is connected to the site-wide network via a network address translation router. The SIS contains standard task logic, Safety Instrumented Function (SIF) logic, and lower-integrity Emergency Shutdown (ESD) logic. A SIL validation was completed to ensure that the sensor and final-element components specified in the original SRS are those installed, and that the new logic solver does not impact negatively upon the individual SIF risk reduction. The standard task logic provides the handshake interface to the DCS and higher-level Allen-Bradley programmable automation controllers. The fill level signals are provided by radar gauges within the tanks. The gauges — from Endress+Hauser, a Strategic Alliance Partner of the Rockwell Automation PartnerNetwork™ — send 4-20 mA signals back to Endress+Hauser trip amplifiers. These send signals to the safety controllers when the level reaches a specific point. The safety controller then sends a command to close the inlet to help prevent overfilling. Results “We now have a system that is fully supported and is at the front end of its lifecycle,” says the site’s Engineering Manager. “Although a like-for-like replacement in terms of safety functionality, the Allen-Bradley controllers deliver more flexibility in how we operate the system because they give us the option of adding more channels if and when needed. The new architecture also offers a better way of operating with the RMA units from Endress+Hauser. “Our E&I engineers like the new set-up and are enjoying the relationship with Actemium Automation.” This project sits at the front end of a much bigger site-wide upgrade project managed by Actemium Automation, the crux of which includes a Rockwell Automation PlantPAx® process control solution. Pulling in multiple elements of the Rockwell Automation Integrated Architecture® system, it provides a fully integrated, sitewide process control system. Rockwell Automation’s responsive engineers help us develop concepts to get the best design, and they provide support through the entire process. They also help us save engineering effort and time, with a case in point being the introduction of pre-built virtualised servers for the new project.