Controlling interest

Process automation suppliers around the world have confirmed the trend for integrated safety instrument systems where a single system is part of a distributed control network.

This trend recently received another boost with the launch of Yokogawa’s VigilantPlant ProSafe-RS, a safety hardware system for monitoring process status and ensuring safety by shutting down a plant in emergencies. The system can be integrated into Yokogawa’s Centrum series of process control systems, eliminating the need to build separate process control and safety systems. As a result, plant information can be managed centrally, and the integrated information means there is greater operational efficiency and safety.

Yokogawa entered the safety instrumentation system business in 1997 with its first IEC 61508-compliant safety controllers. But because their roles and functions are different, process control systems and safety systems have traditionally been constructed separately.

However, there has been a growing need to integrate the two systems to centralise the management of plant information. There is also an increased requirement to enhance the safety and reliability of safety systems, and to adopt safety systems that can flexibly handle plants of all sizes.

At the launch of the VigilantPlant concept earlier this year, Yokogawa’s chief executive Isao Uchidan said that the ambition of the company — already Japan’s market leader — was to be world market leader by 2010. Yokogawa is the third major process automation supplier to release an integrated safety system.

Emerson Process Management and ABB have also launched integrated system in recent months. All three systems are waiting for approvals to safety integrity level (SIL 3) and are currently only shipping as beta versions.

ABB’s system has been approved to less strict SIL 2 and is currently controlling chemical and process plant; it is being developed in the process environment, notably by Dow Chemicals in the US.

Yokogawa is confident of receiving an approval from quality assurance body TUV this month when it will formally launch the product in its commercial form.

Emerson is expecting approval, perhaps as early as May, when it will fully commercialise its SIL 3 system.

As SIL 3 grade is extremely difficult to achieve and maintain, the design of such systems — which have been extremely rare in the process industries — require specialist techniques which need the experience and formal training of recognised, formally trained engineers with appropriate design experience.

Emerson Process Management was first to launch a safety-integrated strategy. The system is an extension of the company’s PlantWeb architecture and takes advantage of proven technologies, including intelligent field devices, predictive diagnostics and digital communications. The integrated safety element extends to transmitters and valve controllers certified to IEC 61508, and SIL 3-rated systems.

The company’s PlantWeb technology enables the user to identify and even predict problems throughout the safety loop and reduce expensive manual proof testing. An important feature is the automated partial-stroke testing of valves, which can improve the safety level, reduce the number of risky personnel trips into the field, and increase the mandatory proof test interval.

ABB’s System 800xA software suite includes production management and optimisation tools to provide the speed and control needed to respond to increasing production demands by modelling, executing, and tracking information associated with material and control flow across the plant. This helps to improve overall batch production profitability, consistency and traceability.

The package includes batch management which is claimed to provide functionality in recipe management, batch and procedural control, safety and security and reduces lifecycle costs and production downtime. It employs a single, system-wide equipment model so equipment modules and other resources are all configured within the same model.

While the launch of two safety integrated systems in as many months could be described as a coincidence, the launch of three, all from different continents, can surely be described as a trend.

And it is a trend that could well signal the demise of triple modular and other redundant systems as we know them.

Invensys, self-styled international production technology and energy management group, would argue against that. Last autumn Hyundai Petrochemical awarded Invensys Korea a $2.5m (£1.3m) contract for a safety instrumented systems. The project includes the replacement of ABB August safety systems with Triconex Tricon triple modular redundant controllers. Invensys claims the Tricon controller provides process plants with a high level of safety and reliability in a package that is easy to configure, implement and maintain.

And this is the second major installation for Tricon controllers at Hyundai Petrochemical, with current systems being used for safety as well as integrated turbine/compressor control.

But traditional safety systems clearly have not had their day. Last year, Honeywell Process Solutions won a $4.3m contract from Motor Oil Hellas (MOH) in Aghii Theodory, Greece, to expand the control and safety systems at the company’s 100,000 barrel/day refinery in Corinth. The system expansion is part of a refinery-wide project to comply with new EU fuel specifications starting this year.

Through this project, the refinery will reinforce its ability to control and monitor the new processes, using traditional methods, while ensuring the safety of daily operation.

So on the face of it, traditional systems have not had their day. And until certification issues are resolved, it is too soon for the fat lady to sing about integrated safety.