When your tower underperforms, the whole refinery feels it

Distillation columns and separation towers are the backbone of refinery and chemical plant operations. They run continuously, under pressure, in corrosive environments — and they are expected to hold to tight product specifications for four to six years between planned shutdowns. When something goes wrong, or when performance quietly erodes, the impact propagates across every downstream unit.

These are the operational issues Sulzer Chemtech encounters most frequently — and what Total Tower Care delivers to address them.

Tray fouling and loss of separation efficiency

One of the most common and insidious problems in refinery towers is gradual fouling of tray decks, downcomers, and distributors. Salt deposits, coke, polymer, and corrosion byproducts accumulate on internals over time, restricting liquid and vapor flow, increasing pressure drop, and degrading the contact efficiency that separation depends on. The atmospheric crude distillation column must run free of shutdowns and maintenance for periods of four to six years, which means fouling that develops in year two doesn't get addressed until the next planned turnaround — unless the situation becomes critical enough to force an unplanned outage.

Total Tower Care addresses this through scheduled inspection and tray replacement during turnarounds, combined with upgrade options: retrofitting higher-capacity tray designs such as VGPlus™ or UFMPlus™ that offer improved anti-fouling geometry and maintain performance across a wider range of operating loads.

Shell corrosion from overhead systems

Crude oil contaminants carry a large volume of corrosive species — acids, chlorides, and saline solutions — that, when in contact with the metallic structures of atmospheric columns and crude distillation overhead systems during operation, affect structural integrity and performance. Amine-based H₂S scavengers compound this further, forming highly corrosive salt deposits in the upper sections of crude columns. Left unaddressed, this leads to shell thinning that reduces mechanical integrity and shortens asset life.

Sulzer's CladFuse™ automated weld overlay technology applies protective alloy layers to damaged surfaces, restoring shell thickness and structural integrity — with one Italian refinery project completed in 32 days, delivering an estimated 20 years of added service life to its atmospheric distillation unit.

Source: Sulzer Chemtech Tower Field Services restarts refining operations at Italian plant | Sulzer

Capacity constraints that limit throughput

Refineries regularly face pressure to increase throughput — through crude slate changes, feedstock switches, or simply market-driven demand increases. Columns designed for a specific capacity and feed composition may flood, lose separation efficiency, or exceed pressure drop limits when pushed beyond their original design envelope.

This is a revamp case: replacing existing internals with higher-capacity structured packings such as MellapakPlus™, or upgrading tray decks to modern high-capacity designs, can recover significant throughput within the existing column shell — avoiding the capital cost and schedule impact of a new column. New internals in the same column footprint can deliver higher capacity and energy efficiency, substantially improving processing operations.

 Energy consumption above design targets

Column reboiler duty directly drives fuel gas or steam consumption — one of the largest operating cost line items in a refinery. When separation efficiency drops due to aged or damaged internals, operators compensate by increasing reboiler heat input to maintain product specifications. The result is energy consumption significantly above design intent, with no corresponding gain in throughput or yield.

A refinery integrating Sulzer's structured packing in its distillation columns reported a 15% reduction in steam consumption following an internal upgrade. Total Tower Care includes process studies and debottlenecking analysis to identify where reboiler overuse is a symptom of an internal performance problem — and what upgrade path addresses it most cost-effectively.

Source: Sulzer Chemtech's Innovative Process Solutions 

Emergency failures and unplanned shutdowns

Tray collapse, downcomer flooding caused by debris, weld failures on nozzles or sumps, or sudden escalation of a known corrosion area can force an unplanned column shutdown. Every day of unplanned downtime in a crude unit has direct revenue impact across the refinery.

Total Tower Care provides field services for emergency plant repairs, combining Sulzer's engineering expertise with global mobilization capability to minimize time between failure and restart. Having a single partner who knows the column — its internals design, mechanical history, and process requirements — compresses diagnosis and execution time compared to assembling a response from multiple contractors.

End-of-life columns requiring replacement

The vacuum distillation unit processes the heaviest oils in the refinery and must run free of shutdowns for periods of four to six years — high reliability is essential, yet this service presents the most challenging conditions. Columns beyond 30–40 years of service often reach a point where repair no longer provides a viable return: wall thickness, nozzle integrity, and the limitations of original metallurgy all converge. Sulzer delivered a complete replacement CDU column — 265 tonnes, 44 metres, 48 trays — in one piece with all internals pre-installed, completing installation within the refinery's planned shutdown window.

The benefits of a new column - Empowering Pumps and Equipment  

One partner across the entire lifecycle

The common thread across all these issues is that they require integrated expertise: process knowledge to diagnose the root cause, equipment capability to deliver the right internals, and field execution to install reliably within a defined turnaround window. Separating these responsibilities across multiple vendors introduces coordination risk and dilutes accountability.

Total Tower Care is Sulzer Chemtech's answer to that: a single point of accountability integrating engineering, manufacturing, and field execution — from the first inspection to the final performance test.

To discuss your tower's specific challenges, contact the Total Tower Care team at totaltowercare@sulzer.com.