Afrox has commissioned a new R200-million air separation unit (ASU) at its Pretoria West site. The atmospheric gases plant will service the merchant and medical markets in South Africa and in other emerging African economies.
Ben Mabelane, Afrox ASU Operations Manager, says the project was as an ideal opportunity to replace an existing plant, originally built to supply Iscor in 1986, with a more energy efficient plant.
“In 1999 Iscor abandoned stainless steel operations at its Pretoria works, resulting in the discontinuation of the supply of gaseous oxygen and nitrogen from Afrox,” explains Mabelane. “Afrox was forced to operate one of its two 750 ton per day (tpd) ASU's at our Pretoria West facility in maximum turn-down mode and as a merchant plant.”
“Over subsequent years, the reliability of the plant began to decline and we took the decision to replace the two historic ASU’s with a brand new 200 tpd ASU.”
Linde Gas, a subsidiary of Afrox’s parent company, The Linde Group, carried out the civil design and the overall project management, with Linde Engineering responsible for the design, supply and erection of the new ASU.
Afrox’s Technical team integrated an existing nitrogen liquefier unit into the new ASU at the site and linked production from the ASU to existing cluster storage tanks. Afrox Technical was also responsible for upgrading the cooling water system, the electrical supply and instrumentation to enable the plant to be operated remotely by a Linde subsidiary in the United Kingdom.
Three cold boxes, an air compressor, coolers, pump skids and PPU skids were shipped from Germany to Durban Harbour and then transported up to Pretoria by road on a flatbed. The molsieve vessels were shipped from Korea.
“With the main cold box being 48m long, it was quite a challenge to transport as an abnormal load and to also lift into position on site,” comments Mabelane. “For road transport, the cargo required permits for each district and a police escort all the way from Durban to Pretoria.”
“The number of role players involved also rendered this project highly complex. However, once roles and responsibilities had been clearly defined and understood by all, execution became very streamlined and activities fell into place as scheduled.”