Raisepower and atg UV Technology have designed a system that combines UV treatment and filtration to treat hydraulic fluids used for subsea blow out preventer (BOP) operations.
BOPs are safety devices used to prevent the uncontrolled flow of liquids and gases during drilling operations. BOPs are typically controlled and operated by hydraulic fluids comprised of potable grade fresh water, glycol-based antifreeze and soluble lubricants with corrosion inhibitors.
If left untreated, the bacteria levels in the BOP controls fluid can quickly rise, leading to microbial corrosion on the fluid lines, corrosion of the BOP and control unit components and seals, and control system blockages. These can lead to critical BOP failure and irreparable damage to the blow out preventer itself.
UV light is a chemical-free, physical disinfection technique that is widely used in the offshore sector for potable water disinfection, reverse osmosis membrane protection and for the reduction of sulphate-reducing bacteria from well injection fluids and produced water.
Unlike standard water treatment applications that use UV disinfection to control bacterial growth, treating BOP fluid using UV is highly specialized. It requires advanced engineering to overcome the barriers regarding UV dose delivery into the BOP fluid, which typically features UV transmittance (UVT) of nearly 0 percent. Standard UV systems are not effective below 30 percent UVT.
Following successful lab and pilot trials to fine tune the design and prove the effectiveness of UV light as a sterilization technique for the mixed hydraulic operation fluid, atg UV Technology and Raisepower installed a fully operational, ATEX Zone 2, IIB, T3 certified UV treatment, filtration and pumping skid package for the Transocean SEDCO 712 rig in September 2013.
After more than a year’s operation, the tanks that feed the BOP fluid mix tank with fresh water, glycol and soluble oil all showed levels of bacteria growth and notable particle contamination. The mix featuring the UV treatment package, however, consistently showed undetectable results in bacteria and solid particle counts.
atg UV Technology also recently introduced a chemical free advanced oxidation process for the treatment and removal of organic and chemical contaminants from municipal drinking water and wastewater.