Jet cleaning device makes light work of sludge cleaning

Cleaning the inside of giant storage tanks at refineries and bulk chemical storage facilities is about to get a whole lot easier, safer and cheaper with the development of a jet cleaning device.

The patented R-jet device is placed inside the tank where it generates a high-velocity rotational jet which re-suspends sediment, and keeps solids suspended so they can't settle and create the tough layer of sludge that currently has to be removed manually.

This normally involves workers using water cannons, shovels or even mini-bulldozers and can mean a tank being offline for several months. Regulations require tanks, which can measure more than 60 m in diameter, to be regularly inspected which means regular cleaning.

Dr Jie Wu, who led the CSIRO team that developed the R-jet device, said the idea of an automated device arose when researchers were helping Exxon Mobil to help decommission its Adelaide refinery a couple of years ago.

"We came up with the idea of a high velocity rotating jet located in the tank for suspending and mixing and cleaning operations so people don't have to do it manually," said Wu.

He said that in the Australian industry alone, manual cleaning costs millions of dollars a year in downtime, labour and direct capital costs.

Wu claims the development of the R-jet also lessens the risk to workers who have to do the actual cleaning.

"At the moment people are still doing it manually in lots of refineries "“ they have to go into the tank and physically remove the sludge," he said.

"They are working in an environment where the vapour can explode."

The dangers of manual cleaning were tragically illustrated in Japan several years ago when four workers at a refinery in Nagoya were killed in an explosion that happened while they were cleaning a tank.

Wu said the R-jet technology can either be permanently installed in a tank to prevent build up of sludge, or installed on a temporary basis.

The R-jet was recently tested in an Australian refinery by Paul White who runs Innobiz Solutions, a South Australian-based consultancy that works with the petroleum and alternative fuels industries.

White said two tanks were cleaned; the first as a demonstration trial and the second under a commercial agreement with the oil company. Both operations were successful. "It's a low-cost alternative that can be justified on safety grounds and economic grounds," he says.

"You get the tank back into service faster and at a lower cost but most importantly without placing workers in hazardous environments."

White believes the R-Jet technology will be suitable for the oil industry, and other bulk liquid industries, world-wide.