Respond to a reactor high temperature abnormal situation

What is going on

Reactor 2 is 40 minutes into the acid addition on a ferric chloride batch when the cooling water supply pressure starts to fall because a cooling tower pump has tripped. The reactor temperature, normally held at 85 degrees, begins to climb towards the safe operating limit of 95 degrees with a trip at 100. Scrubber pH is drifting down as off-gassing increases. Within a few minutes there are twelve alarms on the panel. Tahlia Brennan is in the field near the reactor building. Wayne Djakovic is on the phone to the terminal. The alarm response manual gives response times for each alarm and the abnormal situation procedure sets out when to hold, reduce and shut down. The exercise ends with a shift handover.

Your brief

Recognise and declare the abnormal situation, take the alarm response actions within the response times, protect the outside operator, decide when to activate the emergency shutdown, confirm the safe state, record the event as a process safety event and hand over the plant to the incoming shift.

Work through it

You do not need to do it all. Doing a few of these will show you what the work is like. Your ticks and notes stay on this device.

• Read the abnormal situation and emergency shutdown response procedure and the reactor batch procedure abnormal conditions section, and review the alarm response manual entries for reactor high temperature, low cooling water pressure and low scrubber pH.
• Identify the abnormal situation from the trends and the alarm flood, declare it to the shift supervisor and the outside operator and direct Tahlia Brennan to the safe upwind location.
• Take the manual actions in the alarm response manual: stop acid addition, maximise cooling, start the standby cooling water pump and correct the scrubber caustic dosing, recording the time of each action.
• Track the temperature against the safe operating limit and the response time and decide whether the actions have restored control or whether the emergency shutdown must be activated.
• If the limit cannot be restored in time, activate the emergency shutdown, confirm each shutdown action on the status display and obtain field confirmation of valve positions where safe.
• Notify the Production Superintendent and the Process Safety Manager, save the trends and the sequence of events and record the event in the incident register as a process safety event with the correct type.
• Complete the shift handover report describing the plant state, the standing alarms, the shutdown status and the first actions for the incoming shift.

What someone in this role would produce

• Timeline of alarms, actions and decisions with times
• Emergency shutdown decision record
• Incident register entry as a process safety event
• Completed shift handover report