Sep, 2011

The Sappi Tugela River pump station upgrade project on the North Coast of Kwazulu-Natal took energy-efficiency to a new level as the project resulted in continually reducing the peak-time load on Eskom's grid.

"The Magnet Group was commissioned by Sappi to undertake an audit of the plant, with a view to possibly upgrade one of the pumps," says Brian Howarth, Magnet's managing director. "We are actively involved with Eskom's demand-side management programme (DSM), aimed at alleviating the country's shortage of electricity," he said.

Howarth says that the size and scope of the project increased from the initial focus on a single pump upgrade to a comprehensive turnkey energy-efficiency project, involving the installation of seven new pumps at the plant, new control valves and a new control system and control philosophy.

"The greatest challenge we faced was at the initial stage of the project, prior to pump replacement," he explains. "A thorough audit and analysis were done and involved a series of measurements and calculations around pumping and processing capacities to achieve optimum energy savings at the plant."

Today the Tugela Mill's pump station, with state-of-the-art process control, is capable of pumping the mill's daily requirement of water in less than 20 hours. "There is also a shift in load from peak periods to off-peak periods, using existing water-storage capacity without impacting on the supply of water to the mill," he says.

According to Howarth, the upgrade of the river pump station allows for an average shift of 1,85 MW away from the peak demand periods during the day and an average 0,185 MW energy saving throughout the rest of the day. "In addition to moving load out of the peak demand periods, the overall plant demand is always lower than the previous baseline," he explains. "The reduced energy consumption has been verified in three separate audits by a university measurement and verification team," he says. "Overall, the plant's kWh consumption has been reduced by around 25%. It actually exceeded the guaranteed values."

The upgrade enables Sappi to shut down the entire plant for two hours every night, reducing the strain on Eskom's power grid. "The installation of new pumps and control equipment has enabled automatic start-ups, which was previously not possible. This new equipment has also reduced electricity consumption during normal operation," he concludes.

The Sappi Tugela River pump station project received the 21st Department of Energy/Eskom ETA Award for industrial projects and was also nominated for the Sappi Technology Innovation Awards (TIA) last year.

Magnet
Tel: +27 31 274 1096
Fax: +27 31 274 1073
E-mail: brianh@magnetgroup.co.za
Website: www.magnetgroup.co.za