EDITOR’S CHOICE THE POWER OF PLANNING AHEAD


European chemical plants face a long-term below-capacity outlook. Dennis Filthaus, Senior Industry Consultant EMIA, Octave, outlines the options available to help operators cope with this situation, ensuring the safety and resilience of chemical plants going forward


T


he war in Iran and the resulting closure of the Strait of Hormuz have added acute feedstock and energy price shocks to a European chemical industry already deep in structural downturn. Even


before the conflict, plant utilisation had been stuck at around 75% for more than three years, driven by weak demand and persistently higher energy prices than competing regions – two pressures that the crisis in the Gulf has only intensified. Part of the challenge is that chemical facilities


built across Europe in the past half-century are designed for steady-state, high-volume throughput and not to operate far below their nameplate capacity for extended periods. This leaves European operators with several options to make the best of a bad situation.


Turndown: the risks of the under-utilised plant The first option is a deep turndown: keeping the plant online at a reduced but steady throughput. This strategy suits large integrated petrochemical sites, for example, because shutdowns and restarts carry high thermal and mechanical risk. In a deep turndown, the most immediate


concern is mechanical integrity: for example, low flow can cause corrosion in dead legs and fouling in heat exchangers, while operating outside the design window requires extensive engineering re-evaluation. Equipment must often be re-rated for lower loads.


Operating below capacity also requires greater attention to abnormal situations, via alarm systems or shift handovers. Low throughput creates more alarm activity and more temptation to tune out alarms meant for full capacity. Alarm rationalisation can be a necessary step to ensure that alarms are meaningful and effective 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. It is favoured by fine chemicals and commodity intermediates, particularly those exposed to seasonal demand or feedstock volatility. Rather than running 24/7, facilities may 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 bring the risk of cycling fatigue. Plants designed for continuous use suffer immensely during the transient phases of startup and shutdown. Each cycle subjects vessels and


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pipes to thermal and pressure stress, leading to metal fatigue. Furthermore, 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 Last comes partialisation or mothballing, where selected units such as ammonia plants or crackers are fully taken out of service and preserved 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 this process: 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. Effective MOC is not only a workflow for


approvals. It also keeps the facility ready for re-commissioning and ensures that procedures and training align with the site’s physical configuration. This structured framework can be integrated with the plant’s digital twin to automatically flag affected parts of the 3D model. If an engineer proposes an isolation for mothballing, the system can automatically identify every connected valve and relief device that requires re-validation. Across all scenarios, one of the common risk factors is the human element: As capacity declines, workforce experience often erodes,


PROCESS & CONTROL ENGINEERING | MAY 2026


while operational complexity increases. A key way to address this issue and preserve this knowledge is through better procedure management: ensuring that procedures capture the actual practices through feedback mechanisms that help flag and annotate incorrect or outdated procedures. This is particularly important in a deep turndown phase, where “informal” procedures can stray away from official procedures meant for full capacity.


For intermittent operations, mitigating the loss of veteran expertise can also require mobile tools that provide field technicians with step-by-step, interactive procedures for complex startups, ensuring that safety protocols are followed to the letter regardless of the operator’s tenure. Procedure management should be part of a larger strategy to combat information decay. To do so, European firms are adopting platforms that centralise all asset data, from original 3D CAD models to real- time maintenance logs, to serve as a “single source of truth”. This ensures that the engineering team has an accurate map of the current state of the facility, rather than relying on outdated paper records. Whatever the scenario, effective strategies have something in common: they adapt to the current situations but are also long-term efforts for safer and more resilient plants. Tighter change management, better start-up management, sharper alarm discipline and inspection strategies that keep corrosion risk visible help them meet the moment. But, in doing so, they also make the plant more efficient, should it return to its full capacity in the future. In a global market that no longer guarantees the luxury of full volume, this flexibility will be a long-lasting advantage.


Octave www.octave.com


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