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Cleaning on the Critical Path to Profits
"Like never before, cleaning performance is critical to reducing costs and improving profits."
According to Dan Coombs, the former executive vice president of global manufacturing for LyondellBasell, and a member of our advisory board:
"A refinery or chemical plant relies on three major transport phenomena: momentum transfer, mass transfer, and heat transfer. The failure of momentum or mass transfer becomes evident through immediate operational disruptions requiring plant shutdown and repair. The failure of heat transfer is an insidious process, happening slowly over time and robbing your operation of efficiency and profitability. Historically, for the most badly fouled exchangers, the prospect of perfect cleaning results was not a possibility and the focus in maintenance was to get as clean as possible within the available time window.
Up until now, heat exchanger cleaning has been done mostly during shutdowns in the window of time that appears during the gap between disassembly and reassembly. Up until now, cleaning efficacy has been largely ignored as a key performance indicator in washpad cleaning, or as a factor in Risk Based Work Selection."
"With new cleaning technology like Tech Sonic's ultrasonic cleaning approach coming online, isn't it time for a change?"
A Century of Heat Exchanger Cleaning
Early Technology
The first generation of heat‑exchanger maintenance in refineries was almost entirely manual. Plant crews in the 1920s–50s removed tube bundles, rodded or wire‑brushed the tube side, and used low‑pressure steam jet technology left over from locomotive practice to clean the shell side.
Early experiments with “water jets” had been described as early as the 1800s, but it was only after high‑pressure triplex pumps became commercially reliable in the mid‑20th century that hydroblasting at pressures between 20–40,000 p.s.i displaced hand tools as the dominant method for both shell‑ and tube‑side fouling removal.
The Age of Hydroblasting
Through the 1960s–80s the sheer fouling loads of heavier crudes and catalytic fines pushed operators to combine hydroblasting with chemical circulation. Acid or solvent loops were used to dissolve carbonate, oxide or asphaltene before bundles were pulled, shortening the hydroblasting time. This shift from 100 % hydroblasting to a solvent‑first approach has cut exchanger downtime by reducing the hydroblasting effort required on the washpad.
Safety and labour pressures in the 1990s saw the introduction of the first semi-automated bundle cleaners. Track‑mounted tube‑lancing and shell‑side “shotgun” heads allowed crews to operate equipment away from the direct blast zone, improving both efficiency and safety. Automated water‑jet rigs are now common on washpads and are being further developed today into automated no-entry systems.
A New Century Brings a New Standard
A step‑change arrived in the early 2000s when off‑line ultrasonic baths - the same cavitation physics long used for medical instrument cleaning - were scaled up to multi‑ton exchanger bundles. Tech Sonic (commercial since 2010) and its European licensees demonstrated full‑depth removal of tenacious hydrocarbons and inorganic scales while halving the cleaning time, improving safety and cutting water consumption by almost an order of magnitude. Academic reviews trace the method back to laboratory work in the 1950s, but industrial adoption only took off once transducer arrays and digital power supplies matured.
Over the past decade, Tech Sonic has aggressively developed new washpad technology. By taking a holistic approach - combining its ultrasonic cleaning methods, which have displayed reliable and robust value, with state-of-the-art robotic and data collection - Tech Sonic has reimagined the washpad as a highly effective, efficient, safe and environmentally responsible part of plant maintenance, rather than a "necessary evil".
Viewed over a century, exchanger cleaning has progressed from brute‑force manual labour to high‑pressure hydraulics, to chemical‑hydraulic hybrids, to today’s automated and ultrasonic approaches—each wave driven by the same triad of pressures: turnaround duration, worker safety and, increasingly, water and carbon intensity.
The Industry's Dirty Secret
A Problem on the Shell Side
We've all seen bundles so badly fouled that they were almost unrecognizable. In a large bundle, with hundreds or even thousands of tubes, and fouling completely packing sections of the OD, it's (NOT) a well guarded secret that these bundles cannot be completely cleaned on the shell side, due simply to the way that hydroblasting works. 
Despite often being constructed with square-pitch tubing layouts and so-called "Cleaning Lanes" to permit access, even the best shell-side hydroblasting equipment will struggle to remove fouling from the inner rows of a large bundle. This is simply because the jets of water lose their impact as they pass through the exterior rows, and often the fouling material just gets "pushed around" rather than removed. It is not uncommon for a large bundle to be blasted continuously for days in an attempt to remove as much fouling as possible within the available time.
Our clients have been telling us for years that with hydroblasting, the end result is often a bundle that goes back into service at 75% or less of it's clean heat transfer capacity! This immediately eliminates any design heat transfer contingency and robs your operators of the ability to optimize heat transfer over the long-term, resulting in higher operating costs and shorter intervals.
Trouble on the Tube-Side
The situation on the tube-side is a bit better, because in many cases, hydroblasting lances or other mechanical removal technologies can get the insides of the tubes close enough to 100% clean for inspection. The process however, besides being very time consuming, does have its limits. In the case of hard scales or corrosion, hydroblasting often fails to achieve acceptable results.
In very challenging cases, the potential for damage to the exchangers increases and more and more aggressive pressures and lances are used.
"Like never before, cleaning performance is critical to reducing costs and improving profits."
According to Dan Coombs, the former executive vice president of global manufacturing for LyondellBasell, and a member of our advisory board:
"A refinery or chemical plant relies on three major transport phenomena: momentum transfer, mass transfer, and heat transfer. The failure of momentum or mass transfer becomes evident through immediate operational disruptions requiring plant shutdown and repair. The failure of heat transfer is an insidious process, happening slowly over time and robbing your operation of efficiency and profitability. Historically, for the most badly fouled exchangers, the prospect of perfect cleaning results was not a possibility and the focus in maintenance was to get as clean as possible within the available time window.
Up until now, heat exchanger cleaning has been done mostly during shutdowns in the window of time that appears during the gap between disassembly and reassembly. Up until now, cleaning efficacy has been largely ignored as a key performance indicator in washpad cleaning, or as a factor in Risk Based Work Selection."
"With new cleaning technology like Tech Sonic's ultrasonic cleaning approach coming online, isn't it time for a change?"
Early Technology
The first generation of heat‑exchanger maintenance in refineries was almost entirely manual. Plant crews in the 1920s–50s removed tube bundles, rodded or wire‑brushed the tube side, and used low‑pressure steam jet technology left over from locomotive practice to clean the shell side.
Early experiments with “water jets” had been described as early as the 1800s, but it was only after high‑pressure triplex pumps became commercially reliable in the mid‑20th century that hydroblasting at pressures between 20–40,000 p.s.i displaced hand tools as the dominant method for both shell‑ and tube‑side fouling removal.
The Age of Hydroblasting
Through the 1960s–80s the sheer fouling loads of heavier crudes and catalytic fines pushed operators to combine hydroblasting with chemical circulation. Acid or solvent loops were used to dissolve carbonate, oxide or asphaltene before bundles were pulled, shortening the hydroblasting time. This shift from 100 % hydroblasting to a solvent‑first approach has cut exchanger downtime by reducing the hydroblasting effort required on the washpad.
Safety and labour pressures in the 1990s saw the introduction of the first semi-automated bundle cleaners. Track‑mounted tube‑lancing and shell‑side “shotgun” heads allowed crews to operate equipment away from the direct blast zone, improving both efficiency and safety. Automated water‑jet rigs are now common on washpads and are being further developed today into automated no-entry systems.
A New Century Brings a New Standard
A step‑change arrived in the early 2000s when off‑line ultrasonic baths - the same cavitation physics long used for medical instrument cleaning - were scaled up to multi‑ton exchanger bundles. Tech Sonic (commercial since 2010) and its European licensees demonstrated full‑depth removal of tenacious hydrocarbons and inorganic scales while halving the cleaning time, improving safety and cutting water consumption by almost an order of magnitude. Academic reviews trace the method back to laboratory work in the 1950s, but industrial adoption only took off once transducer arrays and digital power supplies matured.
Over the past decade, Tech Sonic has aggressively developed new washpad technology. By taking a holistic approach - combining its ultrasonic cleaning methods, which have displayed reliable and robust value, with state-of-the-art robotic and data collection - Tech Sonic has reimagined the washpad as a highly effective, efficient, safe and environmentally responsible part of plant maintenance, rather than a "necessary evil".
Viewed over a century, exchanger cleaning has progressed from brute‑force manual labour to high‑pressure hydraulics, to chemical‑hydraulic hybrids, to today’s automated and ultrasonic approaches—each wave driven by the same triad of pressures: turnaround duration, worker safety and, increasingly, water and carbon intensity.
A Problem on the Shell Side
We've all seen bundles so badly fouled that they were almost unrecognizable. In a large bundle, with hundreds or even thousands of tubes, and fouling completely packing sections of the OD, it's (NOT) a well guarded secret that these bundles cannot be completely cleaned on the shell side, due simply to the way that hydroblasting works.
Despite often being constructed with square-pitch tubing layouts and so-called "Cleaning Lanes" to permit access, even the best shell-side hydroblasting equipment will struggle to remove fouling from the inner rows of a large bundle. This is simply because the jets of water lose their impact as they pass through the exterior rows, and often the fouling material just gets "pushed around" rather than removed. It is not uncommon for a large bundle to be blasted continuously for days in an attempt to remove as much fouling as possible within the available time.
Our clients have been telling us for years that with hydroblasting, the end result is often a bundle that goes back into service at 75% or less of it's clean heat transfer capacity! This immediately eliminates any design heat transfer contingency and robs your operators of the ability to optimize heat transfer over the long-term, resulting in higher operating costs and shorter intervals.
Trouble on the Tube-Side
The situation on the tube-side is a bit better, because in many cases, hydroblasting lances or other mechanical removal technologies can get the insides of the tubes close enough to 100% clean for inspection. The process however, besides being very time consuming, does have its limits. In the case of hard scales or corrosion, hydroblasting often fails to achieve acceptable results.
In very challenging cases, the potential for damage to the exchangers increases and more and more aggressive pressures and lances are used.