Tank cleaning technique could drastically cut mud losses

July 1, 2000
Sweden's Consilium Marine Group manufactures a range of products for the marine and offshore industry including "Gunclean" tank cleaning machines.
The Gunclean nozzles are designed for long-term use without maintenance.
Click here to enlarge image

Sweden's Consilium Marine Group manufactures a range of products for the marine and offshore industry including "Gunclean" tank cleaning machines. Since 1967, the company has been supplying the owners of bulk and product tankers with systems based on a single highly efficient cleaning nozzle permanently installed inside each tank.

The cleaning guns have an integrated power and programming unit powered by a turbine driven by the cleaning fluid itself - which could be oil or water-based. Movement of the high pressure nozzles can be programmed according to the design of the tank and the cleaning demands; however, they are generally set to rotate horizontally while at the same time slowly oscillating vertically to produce a helical cleaning pattern.

With the increasing accent on safety and the protection of the environment, Bo Holmqvist, the company's president, believes there are other applications for his well established technology. One is for handling and transport of drilling muds. He is currently holding talks with a prospective partner in the USA with the intention of jointly developing and launching an integrated tank cleaning and mud recovery system.

"There are tremendous economic and environmental drivers behind this idea," he said. "Currently muds are made up in tanks onshore, transferred to supply ships or barges and then to tanks on the offshore installation. Later, the used mud is brought back to the shore for treatment or disposal. There are numerous transfers and different muds need to be kept separate. Cleaning the tanks manually is not easy, and during the whole process a good deal of the mud is inevitably lost or becomes unsuitable for reuse.

80% saving on mud

"Our idea is to install fixed, automatic cleaning nozzles in the various tanks and to use them in conjunction with a mobile recovery unit so that during the whole process there is less chance of cross-contamination and a smaller proportion of the mud has to go for disposal. Our initial calculations suggest we can save up to 80% of the mud that is currently lost. And, of course, the whole operation will be made safer, quicker and more efficient."

Consilium estimates that the payback period for operators on the kind of system it is proposing would be extremely short - it claims that the savings from one cycle of taking mud from the shore to the rig and back could pay for the installation of the system. The only problem as far as Consilium is concerned is that the design of some existing mud tanks makes them difficult to clean automatically. However, Holmqvist feels that once operators begin to see the benefits of the system, they will call for modifications to the design of new tanks to allow them to be cleaned in this way. ;

For more information contact Bo Holmqvist, Consilium Marine. Tel: +46 31 710 7700, Fax: +46 31 710 7800, E-mail: [email protected]