Visbreaker tower safe entry cleaning 

Challenge

Refiners often look for solutions to decontaminate visbreaker units. One of our customers in Southeast Europe was preparing equipment for de-coking and require decontamination of their visbreaker tower, associated vessels, and piping for the preparation of the unit for safe entry. ZymeFlow’s strategy targeted equipment that included feed surge drum, heater, soaker vessel, main fractionator tower, strippers, O/H reflux drum, steam generators, O/H compressor KO drum, among others.

Solution

The engineered solution for decontamination started with a viscosity wash using ZymeFlow’s solvent chemistries during gasoil circulation procedure. The light cutting oil was circulated from the feed circuit to the main fractionator and back to the feed drum from the tower bottoms. After circulation, viscosity wash fluids were drained,  and steam was introduced to the unit.  A boil out was applied at the bottom section of the main fractionator and soaker drum in combination with ZymeFlow Vapour- Phase® process.  These procedures in combination eliminated all H2S, LEL, and Benzene and broke down all heavy material in the visbreaker tower - saving 5 days of de-coking and maintenance.