Bayer’s Crop Science Division develops active ingredients for crop protection as well as the relevant production processes. The manufacturer wanted to bring all the necessary processes under a single roof so that products can be produced faster and more individually. As a longstanding business partner and automation specialist, Festo was invited to get involved in the planning an early stage.
The project turned out to be a demanding task for the engineers. Bayer designed its new facility so that subsystems and equipment can be flexibly connected and operated. The process control system is broken down into 67 automation systems, so that process control can be flexibly adapted as well. At the same time, additional demands were placed on explosion protection. Not only does Bayer process flammable liquids during operation at its facility, the ongoing process development also necessitates numerous interfaces and intervention points because processes are frequently changed. As a result, the entire facility was classified as potentially explosive zones 1 and 2.
The more reliable the components and processes are, the safer the overall chemical plant is. This includes the availability of coolant water as well as electricity, emergency stop and pressure-relief devices, pumps, mixers and process valves. The functional safety of all processes depends on the correct functioning of all important elements, from system operation to the safety functions for instrumentation and control engineering (ICE).
Specially tried and tested ICE components are decisive for the safety of process systems in chemical and petrochemical plants. They not only help to avoid overpressure and other dangerous system states, they also enable trends to be detected at an early stage so that effective countermeasures can be implemented (in some cases automatically). For example, a runaway reaction can be detected by calculating the temperature gradient.
The more reliable the ICE components are, the more efficiently the process system functions. Even if a process engineering system has already been largely optimised, increased output is still possible with a system without downtime. Tried and tested ICE components, certified to IEC 61508, reduce inspection cycles and inspection time to a minimum and ensure that no unplanned downtime occurs due to repairs. As a result, the entire facility remains productive continuously.
Bayer Crop Science's multi-purpose facility includes numerous ICE safety devices from Festo. Amongst other functions, they switch dosing, exhaust and steam valves to failsafe positions. This in turn has consequences for the solenoid valves that control the actuators: they must (for a single-channel architecture) have at least the same SIL classification as the entire safety circuit.
In practice, the extremely low demand mode represents a special challenge for the engineering design and the components used as a solenoid valve is usually built for several million switching cycles. In a safety circuit, on the other hand, it may be energized for decades under certain circumstances and must still react reliably in case of emergency. In scenarios like that, you are only on the safe side with components that have proven they can withstand the ravages of time.