Ammonia splitting unit
Rupture of coil pipes inside ammonia splitting reactor, risk for material damage/downtime. Small leaks from inlet of ammonia splitting reactor due to wear out failure. Hydrogen gas will first be released followed by ammonia. May cause frequent smelling problems at filling station. Environmental risk. Ammonia splitting not working properly due to circuit failure. Consequence may be liquid slugs in compressor. Risk for material damages/downtime.
Filling hose designed to withstand external impact
Regular checks of rupture valves
Driver present during filling
Double walled storage tank with gas detection in shell coupled to a warning system should be evaluated
Installation of temperature control inside NH3 splitter which will stop supply of ammonia
Capacity of ammonia absorption process should be designed to minimize this problem
Install system for detection of failure coupled with shut down of NH3 supply
Monitoring of ammonia content in hydrogen/nitrogen mixture or at outlet of reactor coupled to emergency shutdown
Table 2 Results from risk assessment of production concept 2: Hydrogen production by methanol
Process unit Methanol storage
Identified hazards/risks Rupture of methanol storage tank. Environmental risk.
Suggested risk reducing measures Drainage systems should be designed for the whole tank capacity. Interceptor drainage (will be able to drain 7000 l effectively)
Fire in methanol storage tank. Risk for people and environment.
Tank is designed to withstand 2 hours fire exposure (standard)
Stage 1 vapour recovery. Pressure vacuum valve.
Methanol/water leak to the hot oil system in vaporiser or reactor Material damages, downtime. Gas leaks (H2, CO and CO2) to atmosphere, risk for toxic exposure of persons, fire risk. Explosion risk especially if plant is placed in container.
Double walled tanks Quality check of water and methanol
Isolation/segmentation valve CO detection Separation of units to prevent backflow from PSA unit. Fast depressurisation Explosion relief