Heat exchangers are components of the heating or cooling systems used in various heavy industries. The units transfer heat between two adjacent fluids without letting them mix. The version commonly used in the petrochemical industry, called a shell, involves fluid flowing over the outer surface of a bundle of pipes filled with a different fluid. Shells are subject to fouling, meaning build-up of gunk on the outer surfaces of the pipes. Fouling can have various chemical and physical causes. In the oil and gas industry, fouling is a particular problem, severely affecting a refinery’s energy performance. Globally, fouling costs industry around EUR 18 billion per year. The space between the shells’ pipes is notoriously inaccessible, and so difficult to clean. Conventional cleaning requires removal of the shells, which are hosed with high-pressure water. Yet this method is ineffective, leaving behind 60 % of the fouling while wasting about 80 % of the water. Chemical cleaning is another conventional option, but can have serious environmental consequences while also potentially corroding the shells.
Intelligent, combined process
The EU-funded ShellJeTTPlus project developed a more effective alternative process, called Shell Side Jet. The automated method, applicable to any shell of the ‘square pitch exchanger’ type, completely removes fouling from the spaces between a shell’s pipes without causing damage. The technique involves high-pressure water and carefully controls the risks via fully remote operation. “Shell Side Jet is a world first,” claims Henry Mwai, project manager. “The technology has been designed to slide in between the 6-millimetre-tube corridor space. The system intelligently reads the shell, delivering detailed live reports about key measurements which might indicate bent tubes, the location of and condition of any damage, and the extent of fouling.” The system also photographs the shell before, during and after the clean. Mwai says this protects the assets, ensuring a more precise clean.
A thorough clean
Project testing validated the final product in an industrial environment. The system has been confirmed to clean more than 90 % of gunk between 6 mm-tube rows, regardless of the degree of fouling. The unit was also shown to conform to the shape of the tube and automatically detect blockages, broken tubes, and incorrectly positioned baffles. No competitor system offers comparable results. Tube Tech International, the project’s lead partner, will soon begin marketing Shell Side Jet globally. “The world went into Covid-19 lockdown just as we were at the commercial launch phase,” adds Mwai. “The logistics of not being able to travel internationally, move equipment or access plants, has affected our timeline. Discussions with clients have slowed, but demand is high, and we are planning projects into 2021.” The system is supplied with a comprehensive training programme and the team will be working with partners in Europe, North America and Asia.
ShellJeTTPlus, fouling, heat exchangers, shells, cleaning, Shell Side Jet