A cryogenic air-separ- ation plant, said to be the largest oxygen-producing plant in the Southern Hemisphere, was commissioned by Air Liquide for Saldanha Steel, in the Western Cape, in December, reports Air Liquide central sales and marketing manager Lee Furby.

The plant, which is able to produce about 2 500 t of oxygen a day, is part of a multimillion-rand contract between the gas manufacturer and the steel mill and the oxygen will mainly be used in the steel-manufacturing process.

Compressed air and nitrogen are also being supplied to the project.

The plant features one of the largest air-compressors available from Sulzer, a boost compressor from Borzig which delivers air to the air-separation process and Saldanha Steel itself, pumps to pressurise the gas stream instead of gas-compressors, argon produced by cryogenic distillation and high-efficiency exchangers.

Because the steel mill’s consumption of oxygen is of such a magnitude it was decided that it would reap the most benefits in terms of gas availability and cost with the establishment of an on-site air-separation plant, says Furby.

Having gas on-site not only improves safety but offers the customer independence from the supplier and the opportunity to run 24 hours a day, he adds.

Last year the company completed another large on-site oxygen-producing plant for Botswana Copper, that supplies 200 t of oxygen a day to support a copper furnace.

The establishment of another 25 smaller gas plants was also undertaken, and this year it is expected that the company will reap the benefits of its investments, reports Furby.

In other developments the company has introduced a successful 180 kg mini bulk tank delivery system for carbon dioxide to McDonalds, where the gas is used to carbonate the restaurant chain’s soft drinks.

The tanks, pressurised at ten bar, are equal to five conventional 150-bar gas cylinders and provide a cheaper, safer and more hassle-free alternative to cylinder filling.

Each tank is placed in the restaurant and filled routinely on a milk-run basis from a delivery truck that has been specially equipped for this purpose.

A pipe is attached from the truck to an outlet protruding from the outside wall of each restaurant and the tank takes about ten minutes to fill up.

The stainless-steel tanks are fully imported from the US.

“Since the tanks have no moving parts and remain static at a low workable pressure, they require little maintenance and are significantly safer than conventional cylinders for optimum carbonation,” reveals carbon dioxide co-ordinator Tom Sowry.

Instead of a product, the company now supplies a full service, leaving the customer to concentrate on his own business, he says.

Since its introduction to the market last year, more than 40 restaurant franchises in Gauteng and Durban have been fitted with the mini bulk carbon dioxide system.

A number of smaller restaurants and pubs have also been served successfully with the system and the company expects to provide the market with another 80 units this year.

Five of the units are located at Sandton City where it supplies gas to some of the restaurants and Ster Kinekor.

Since the tanks are filled routinely, the customers no longer need to order gas and the danger that they will run out of gas at a critical time is eliminated.

This year the company is expecting greater levels of competition from the other large gas manufacturers in South Africa and, to stay ahead of the game, it is working towards improving its service levels to be equal to its other subsidiaries around the world, reveals Furby.

“The local gas industry, with its combined large and small users, offers a number of challenges to local gas manufacturers,” he says.

To keep up with technological advances the company has established five research centres around the globe to develop ways of increasing the applications for gas.

“New gas mixes are developed every day and the company that finds the first successful application of that mix is the one that will be victorious in the end,” explains Furby The company spends about R1-million a day worldwide on research and development, he adds.

One of these developments is the replacement of compressed air with nitrogen in motor vehicle tyres, which offers longer tyre life, more retreading possibilities and eliminates rust, reports Furby.

This year the company hopes to increase its presence as a regional competitor with the establishment of an office in Swaziland in addition to offices in Botswana, Ghana and Nigeria.

“The African gas industry is developing faster than generally perceived and many African countries, which were believed to be left out of the world market, are moving forward by applying new technology available to them,” Furby tells Engineering News.

Air Liquide’s training centre, which was established last year for customer development, has been welcomed in the industry, reports national training manager Robert Lawrence.

“The centre has not only made our customers more knowledgeable on the safe use of gas, but has opened more avenues in possible gas applications for the company,” he says.