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
- 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