Underwater laser cleaning for marine and offshore applications

Abstract

Underwater constructions such as offshore platforms and marine structures often need on-site processing for building and repair works. The surface contaminants such as oil, rust, fouling material, biofilm and deteriorated paint can seriously affect the underwater work. Underwater surface preparation is always necessary to remove contaminants for achieving good processing quality. Most of the conventional cleaning techniques are limited by the critical conditions of the environment underwater. Laser cleaning method can be a suitable approach for underwater work with significant advantages such as ecological benefit, localized treatment, noncontact working mode, and the flexibility for processing complicated geometries. The advance of high-power fibre laser techniques allows cleaning work being done by lasers in critical underwater conditions. This work focuses on laser removal of the crude oil from steel plates in water. It is found that the underwater cleaning is different from that of dry laser cleaning that is based on combustion. The property of laser pulses signifies an important role for underwater laser cleaning process.