BetzDearborn and Pfaudler form Reactor Cleaning Alliance
By removing scale, deposits and corrosion, OptiTherm helps restore heat transfer efficiency, increase production rates, improve product quality and reduce maintenance and operating costs.
The alliance combines Pfaudler's resources as a leading supplier of glass-lined equipment with BetzDearborn's patented Ferroquest iron deposit removal technology. Ferroquest provides safe, effective cleaning of glass-lined steel reactor jackets. This non-corrosive technology removes costly deposits at a neutral pH level without generating hydrogen, which can penetrate the glass/steel interface, leading to glass damage.
"The goal of this collaboration is better reactor efficiency, with an eye on improving heat transfer," said Ralph Exton, pharmaceutical industry marketing manager at BetzDearborn. "We feel the primary way to do this is by chemically cleaning the reactor jacket to remove foulants that hinder heat transfer. Reactors use a variety of heat transfer fluids, including steam, tower water, ethylene glycol, calcium chloride brine. We'll examine whatever fluid is being used and make sure it is inhibited as far as corrosion is concerned," Exton stated.
In addition to cleaning services, the alliance will provide recommendations on piping configurations, water management, and the use and direction of agitating nozzles, impingement plates, and deflection shields.
"To provide all these services requires Pfaudler's expertise on the mechanical side of things, plus BetzDearborn's knowledge of chemical treatment. So any job we do together will include a representative from both companies," Exton said.
Ferroquest
Glass-lined reactors and reactor jackets have unique cleaning needs. Corrosion, and deposit buildup severely reduce the efficiency and lifetime of expensive reactors, yet reactor manufacturers strongly discourage the use of traditional acid cleaning.
That's where Ferroquest comes in. Because it works at neutral pH, Ferroquest reduces exposure risks for workers and equipment while sparing the environment.
Major benefits of Ferroquest:
- Extends equipment life
- Eliminates risk of glass damage
- Restores heat transfer efficiency
- Lowers maintenance and operating costs
- Increase production rates and reactor efficiency
The majority of glass-lined reactors and reactor jackets used in the pharmaceutical and chemical processing industries are constructed from mild steel, as are many bath or semi-continuous processes in the specialty chemical industry. Waterside conditions within the jackets during operation produce ideal conditions for corrosion. Over time, thick deposits of corrosion products accumulate reducing reactor efficiency. Iron oxide deposits create areas where under-deposit corrosion occurs, usually in the form of pitting corrosion, which severely reduces the lifetime of the reactor.
Acid cleaning is strongly discouraged by manufacturers of glass-lined steel reactor vessels because the reaction between acid and metals liberates hydrogen atoms which migrate through the wall of the mild steel. When these atoms reach the interface with the internal glass lining, they combine to form hydrogen gas. When this gas builds up, it generates a very high internal pressure, resulting in destructive blistering of the glass lining.
Ferroquest is a blend of organic complexing agents, reducing agents, corrosion inhibitors, and surfactants that remove iron oxide deposits at a neutral pH. Ferroquest cleaning solution is circulated through the reactor jackets 24 hours/day to ensure continuous flow over the fouled surface. Throughout the cleaning, pH, conductivity, corrosion rates, cleaning solution temperatures and iron levels are monitored.
When the iron level reaches a plateau, cleaning is complete. The jacket is then flushed and the vessel is returned to service.
The neutral Ferroquest cleaning procedure does not generate hydrogen and will not damage the glass lining. Corrosion is therefore kept to a minimum. Following cleaning, metal surfaces are protected with a passivating film.
Ferroquest at Work
A chemical manufacturer in Tennessee uses a combination of steam and cooling tower water to heat and cool its glass-lined reactors. This constant switching between steam and cooling water accelerates iron corrosion. Iron deposits foul the reactor jackets, reducing heat transfer and increasing batch time.
Since acid cleaning was not an option, BetzDearborn cleaned the system with Ferroquest, which removes iron oxide deposits at neutral pH and does not generate hydrogen gas, which may cause spalling and blistering.
In addition to cleaning, BetzDearborn evaluated the water-side conditions in the jacket and determined that an enhanced treatment program for the cooling towers was also needed.
As a result of these improvements, approximately 30 pounds of iron was removed from the system, which increased heat transfer more than 30% and reduced reaction time by more than 30 minutes per batch, which was significant. Cooling tower performance was also improved.
For more information: Jim McIntyre, BetzDearborn Inc., 200 Witmer Road, Horsham, PA 19044. Phone: 215-773-6328; Fax: 215-773-6577.