Case Studies

Project
Primagaz in Zutphen, Netherlands, fills propane gas from tanks into cylinders for delivery by truck to  endusers located throughout the country. On site, the gas is stored in large tanks which, for safety reasons, are buried in the ground and surrounded with special sand that forms a protective layer.
To ensure the requisite safety throughout the site, the system integrator Clearvision has implemented a PROFINET-based solution for monitoring the different areas.

Solution
Henk Theunissen, the Clearvision manager responsible for developing and installing the system, recounts: “The most critical function of the solution is to protect the site boundaries. In addition to the usual fences, large lights were installed to discourage trespassing by unauthorized persons anywhere on the property line. Moreover, access to the property is secured and monitored with a camera system.”
In addition, an emergency stop system comprizing 20 stop switches is integrated to serve as protective equipment for the stored gas. If one of the emergency stop switches is actuated, the system will switch off the control voltage, water will be provided for fire extinguishing and so on.
Clearvision also designed a gas detection system with different alarm stages: If a gas leak occurs, this is indicated initially by a signal only. Safety measures are then introduced, followed in the next stage by a flame detection. The solution also processes technical messages, such as error messages from tanks and compressors.

The solution is based on an intrinsically safe system that signals interruptions immediately. The PROFINET real-time Ethernet standard was selected for communication because it provides the reliability needed for this. Henk Theunissen explains: “TCP/IP signals can additionally be transmitted via the PROFINET network. We make use of this capability for carrying out communication with the cameras, access security system, and PROFINET controller. The safety and management system integrates all of the individual systems and visualizes them graphically. A Phoenix Contact PROFINET controller is connected to the network and exchanges data with several remote I/O stations installed at the control and monitoring locations. The surveillance cameras also transfer their data via PROFINET.

Conclusion
The safety and management concept has been in operation since November 2009. Only 2 days were required to retrofit the predecessor system. Primagaz Plant Manager Hans Grotentraast is enthusiastic about the PROFINET-based solution: “The system is straightforward and user-friendly. In contrast to the previous solution, all information is now displayed with a high level of detail. In addition, the cameras provide us with a continuous view of everything that is happening at the site, such as loading and unloading of trucks.” The new system is also proving to be much more reliable than the old approach.