A Polyolefins petrochemical plant based in Ferrara, Italy, was looking for a new coating system for their reactor, operating between 70ºC (158ºF) and 80ºC (176ºF) and processing salt, caustic and titanium tetrachloride. The original hot applied PTFE lining required maintenance due to localised disbondment, caused by minor abrasion of the titanium compound. As a result, the plant was facing a long downtime, between two and four weeks, as it was not possible to conduct an in-situ repair.
The Maintenance Manager was keen to keep the downtime to an absolute minimum and ultimately decided to replace the PTFE with a 100% solids modified epoxy novolac system, Belzona 1593, designed for high temperature immersion up to 160ºC (320ºF). Belzona 1593 was hand applied onto the reactor in April 2015, facilitating its return to service within only four days. An added benefit, which was considered during material selection, was the servicing of the lining. As this system is applied at ambient temperatures and adheres well to metal and itself, it can be repaired in situ when necessary. A similar epoxy system, for instance, has now remained in service on a test separator at a North Sea platform for 20 years, being patch repaired once every decade.
The reactor was opened for inspection in September 2015 and the Maintenance Manager was very satisfied with the result. Moreover, they were able to save time by steam-cleaning the reactor, which was not previously possible with the PTFE. They are now looking at replacing the lining on other existing reactors as well as protecting new reactors with the same 100% solids modified epoxy novolac system.
Savings resulting in reduced downtime along with simplified cleaning and maintenance protocols in this case significantly outweighed the initial cost of material.
Belzona 1593, introduced in 2014, is the latest addition to the range of Belzona lining materials, designed for high temperature immersion. Incorporation of rubbery domains into the polymer matrix of this modified epoxy novolac material allows the material to display a greater flexibility and creep resistance, improving in-service performance.