Exothermic reactors
| Deviation | Typical causes | Typical consequences | Typical safeguards |
|---|---|---|---|
| High temperature | Loss of cooling; excess feed; wrong catalyst charge | Runaway reaction, overpressure, rupture, toxic release | Temperature alarm; high-high temperature SIF stopping feed; emergency cooling; relief sized for runaway |
| Wrong sequence | Reactant added before solvent or before heating to the minimum temperature | Accumulation of unreacted material, then runaway | Permissive interlocks; procedures; checklists |
| No agitation | Agitator trip | Poor heat transfer, local hot spots, accumulation | Agitator running permissive on feed; low power alarm |
| Contamination | Water, wrong material | Side reactions, gas generation | Raw material checks; dedicated lines |
| Loss of inerting | Nitrogen supply failure | Flammable atmosphere in the head space | Oxygen analyser; low nitrogen pressure alarm |
Fired heaters
| Deviation | Typical causes | Typical consequences | Typical safeguards |
|---|---|---|---|
| Flame failure with fuel flowing | Fuel pressure upset, burner instability | Fuel accumulation, firebox explosion | Flame scanners; burner management trip closing fuel valves |
| Low process flow in a pass | Pump trip, control failure, coking | Tube overheating, rupture, fire | Low pass flow alarm and trip |
| High fuel pressure | Regulator failure | Flame lift-off, unstable combustion | High fuel pressure trip |
| Low combustion air | Fan failure, damper closed | Incomplete combustion, CO, explosion on air restoration | Low air flow trip; purge before re-light |
| Tube rupture | Overheating, corrosion | Fire in the firebox, possibly stack fire | Skin temperature monitoring; steam snuffing; emergency shutdown |
Written for First Out AI as engineering guidance. It supports engineering work and does not replace it; check every value against your standards, certificates and company rules with a competent functional safety engineer.