This article explores how to make the best of a bad situation
Chemical facilities built across Europe in the past half-century are designed for steady-state, high-volume throughput, not to operate far below their nameplate capacity for extended periods. This leaves European operators with several options to make the best of a difficult situation.
Turndown: the risks of the under-utilised plant
The first option is deep turndown: keeping the plant online at a reduced but steady throughput. This strategy suits large integrated petrochemical sites because shutdowns and restarts carry high thermal and mechanical risk.
The most immediate concern is mechanical integrity: low flow can cause corrosion in dead legs and fouling in heat exchangers, while operating outside the design window requires extensive re-evaluation. Faced with this situation, engineers use tools such as Octave Aspect Pipe Stress and Aspect Pressure Vessel to revalidate piping systems and vessels under the new load conditions, with results feeding directly into the facility’s digital twin to keep models, drawings and operating documentation in sync.
Engineers would use a piping stress analysis model, via a tool such as Aspect Pipe Stress, to revalidate piping systems after process changes such as altered temperatures or flows during turndown
Operating below capacity also demands greater attention to abnormal situations. Low throughput generates more alarm activity and more temptation to tune out alerts calibrated for full capacity. Alarm rationalisation, supported by a platform such as Octave Tempo Operations Management, is often a necessary step: it provides a unified view of alarm, control and protection performance, helping engineers analyse alarm floods and reconfigure limits so that alerts remain actionable during abnormal and transitional states.
Intermittent shutdowns: stop and restart
Deep turndown is viable mainly for integrated or technically flexible facilities. For older assets or less forgiving segments such as commodity petrochemicals, two other adaptation strategies are common.
The first is campaigning, or intermittent operation, favored by fine chemicals and commodity intermediates exposed to seasonal demand or feedstock volatility. Rather than running 24/7, facilities aggregate orders and run at full tilt for a few weeks, followed by periods of “hot standby” where the plant is kept warm but idle.
Intermittent operations introduce cycling fatigue. Each startup and shutdown subjects vessels and pipes to thermal and pressure stress, leading to metal fatigue. The most dangerous moments in a chemical plant’s life occur during restarts, which with campaigning can happen several times a year instead of once every few years.
Mothballing: combining partial operations and full readiness
The third option is partialisation or mothballing, where selected units such as ammonia plants or crackers are fully taken out of service while higher-value units continue operating.
Partialising a complex facility fundamentally changes how the remaining units operate. Relief systems must be re-rated, shared systems re-dimensioned and new bypasses and isolations put in place.
Two things are critical throughout: engineering re-validation and a maintained digital thread. Without them, the mothballed facility becomes a black box and restart carries serious risk. Formal management of change (MOC) captures each modification and routes it through the required risk assessments and technical reviews. A platform such as Octave InConcert supports this by consolidating engineering, operations and maintenance data into a single source of truth, so that every change is traceable and the asset record stays current.
Keeping a digital thread of a mothballed unit helps keep track of the changes and carry out engineering re-validation to ensure that the plant still operates safely under the new operating regime
Effective MOC is not only a workflow for approvals. It keeps the facility ready for re-commissioning and ensures procedures and training align with the site’s current physical configuration. Integrated with the plant’s digital twin, it can automatically flag affected parts of the 3D model: if an engineer proposes an isolation for mothballing, the system identifies every connected valve and relief device requiring re-validation.
Mitigating human risks
Across all scenarios, a common risk factor is the human element: as capacity declines, workforce experience often erodes while operational complexity increases.
A key response is better procedure management: ensuring procedures capture actual practices through feedback mechanisms that flag and annotate incorrect or outdated steps. This is particularly important during deep turndown, where “informal” practices can drift from official procedures written for full capacity.
For intermittent operations, mitigating the loss of veteran expertise requires mobile tools that give field technicians step-by-step interactive guidance for complex startups, ensuring safety protocols are followed regardless of the operator’s tenure. Octave Tempo Operations Management addresses this directly, combining digital shift management with guided work execution that is accessible in the field.
Procedure management should be part of a broader strategy to combat information decay. European firms are adopting platforms such as Octave InConcert that centralise all asset data, from original 3D CAD models to real-time maintenance logs, giving the engineering team an accurate map of the facility’s current state. Alongside this, Octave Attune APM tracks inspection intervals, corrosion monitoring and asset condition as equipment operates outside its normal throughput range, keeping the risks of below-capacity operation visible and controlled.
Whatever the scenario, effective adaptation strategies share a common quality: they respond to immediate pressures while building toward safer and more resilient operations. Tighter change management, sharper alarm discipline and inspection strategies that keep corrosion risk visible all help plants meet the moment. They also make the plant more efficient should it return to full capacity. In a market that no longer guarantees full volume that flexibility will be a lasting advantage.
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