Reliability is the key for Port Augusta Power Station

Port Augusta’s power station north of Adelaide was first commissioned in 1954. The Electricity Trust of South Australia (ETSA) constructed the station specifically with boilers capable of burning coal mined from the nearby Leigh Creek. The station is currently owned by Alinta Energy.

When Alinta recently decided to install a desalination plant for the power station operation, the tender was awarded to Aqueous Solutions. However, the tender required a very high recovery rate of 94%.

Desalination is important in power stations for the production of steam for spinning turbines, condenser cooling and general plant maintenance. Lack of suitable water can quickly lead to delays and power loss.

The Port Augusta system capacity was to be capable of producing 1,200,000 litres per day. Grundfos pumps were chosen for this challenging assignment.

The containerised desalination plant installed by Aqueous Solutions needed to be an automatic, programmable operation with remote monitoring systems, multimedia filtration, integrated cartridge filtration and antiscalant dosing.

Also needed was a four-stage system designed with system pumps using variable speed drives (VSD) for maximum efficiency and upgrading of the cleaning-in-place (CIP) system including multiflush and backwash procedures.

Importantly for Aqueous Solutions:

• The dosing pumps had to be reliable;
• Full alarm monitoring capabilities were required;
• Spare parts had to be readily available;
• Equipment had to be accurate to conserve chemical use.

Grundfos DDA Smart Digital pumps were suggested as they offered not only reliability but state-of-the-art drive technology through the use of a powerful and economical variable-speed stepper motor.

The pumps have two output relays that can be used for external alarm monitoring. The in-built, easy-to-read LCD screens on the pumps feature backlit visual indication by way of traffic light colours - green is good, yellow is warning due to alarm and red is stopped.

Grundfos spares, such as those for the DDA Smart Digital pumps, are available in a range of service kits that the company carries in stock. For preventative maintenance, the pump not only has a warning message to advise when it is time to fit a new service kit; it even gives the part number of the kit.

The pumps have a turndown ratio of up to 3000:1 while maintaining high accuracy and continuous full stroke length, ensuring smooth dosing with automatic flow control monitoring on the FCM model used in this application. Pumps used in the project ranged from the main system pump to a concentrator pump, cleaning and flush pumps, antiscalant, acid and sodium metabisulfite (SMBS) dosing pumps.

Aqueous Solutions’ Matthew Harrison says the Grundfos pumps are performing as expected.

“They are our standard supplier,” he said.

“We have some units with pumps that have gone over 60,000 hours on some tough bore water.

“We also used the full alarm monitoring capabilities of the DDA pumps. This was crucial because failure of the dosing pumps would have a huge impact on a high recovery desalination plant such as this.

“Reliability is everything.”

While Aqueous Solutions continues to use Grundfos equipment, Alinta Energy has also confirmed that all Grundfos pumps in the desalination plant are performing according to their published pressure and flow curves.

Alinta’s Special Engineer Mechanical, Brett Edwards, says his company was more than happy to have Grundfos pumps incorporated in the project because of their small footprint, suitable materials, good efficiency and reasonable pricing.

“Grundfos also provides reasonable supply times,” he added.