Emergency Shutdown (ESD) System of the Fertilizer Plant

Emergency Shutdown (ESD) System of the Fertilizer Plant
Reliability of plant improves by proper design of the ESD system.
Process dynamics of Ammonia / Urea complex are fast and during any upset the plant may
be tripped in a few seconds if there is a delay in operator intervention. ESD system design
consists of:
- Field Input Measurements
- Interlock Logic Solver
- Field Activation Elements
In the course of years of development, vendors have improved and updated the ESD system
of Ammonia plant to use latest Programmable Logic Controller.
The reliability of a modern Ammonia / Urea complex has improved due to consideration of
the following during the design of the ESD system.
- Sensing element redundancy (voting logic)
- Use of analogue devices
- Utilization of high integrity reliable logic solver
- Separating the ESD system from the process Control layer
- Design of effective alarm systems
- Understanding of the Failure Modes
- Use of known and proven technology
- Test Safety System periodically
- Ensure Management Control of Changes & System by passes / Understanding human
errors.