Urea Reactors form the centre of any urea plant. High pressures and temperatures, the corrosive circumstances and the health risks of ammonia in case of a leak put high demands to the integrity of such a vessel. The UreaKnowHow.com Incident Database introduced three years ago includes al-ready 21 serious incidents with Urea Reactors and other similar High Pressure Equipment items.
This paper includes the Risk Register of a Urea Reactor with a 316L Urea Grade liner. This design is typical for most urea reactors currently in operation. The Risk Register is a collection of possible hazards that can occur in such a urea reactor and includes the related mitigation measures: 37 safety hazards are identified and 37 recommendations / barriers are defined. These recommendations are categorized in this paper for each phase of the life of such a reactor, starting with the design and construction phase, commissioning and operational phase and maintenance phase. This list forms a perfect learning tool about why certain operating and maintenance procedures are done as they are done. One learns Why instead of only What.
A fact that proves to be unexpectedly enlightening is that one can conclude from the Risk Register that 65% of the identified hazards can be mitigated by operating a proper leak detection system. This paper will also define the requirements of such a leak detection system, that follow again from the Risk Register.