Endress Hauser Australia were appointed as the instrumentation supplier and automation design partner and also tasked with the installation and commissioning of all process instruments at the Perth Seawater desalination plant. Among the Perth Seawater desalination plant’s accolades are awards for construction excellence and project management. At the heart of the plant is an instrumentation and control strategy that has made the project a model for other desalination plants not only within Australia but also worldwide. This strategy has also propelled the desalination plant to win in the Zenith Awards.
In 2005, Endress + Hauser Australia were involved with the two joint ventures even at the project bidding phase. Endress + Hauser Australia’s Profibus expertise, comprehensive instrument range, competitive pricing and global presence were the deciding factors that led to the involvement even at an early stage. The MDJV consortium that eventually won the Perth desalination plant project included the major European company Degrémont, which specialise in the design of water treatment and desalination plants.
For the Perth desalination plant situated at Kwinana WA, Endress + Hauser Australia worked with Degrémont’s Australian office to lay the groundwork for the system design. Degrémont subsequently opted to do the bulk of the detailed design at its office in Spain.
For over eight months, Endress+Hauser’s Spanish office worked with their counterparts in Australia and, drawing on their vast Profibus expertise, developed the detailed instrumentation design with Degrémont. For a contract worth $780,000, Endress + Hauser Australia have supplied all flow, pressure, level and temperature devices as well as a vast selection of water analysis instruments.
The Perth desalination plant’s design philosophy was evident in the built-in redundancy for important measurements such as pH/ORP, conductivity, residual chlorine and turbidity. Two sets of instruments were installed in parallel at critical stages to ensure that, even in the rare instance of instrument failure, the water produced retained the desired high levels of purity and quality.
During the implementation stage, this pioneering project threw up a host of unique challenges for the instrumentation team. The electromagnetic flowmeters were affected by eddy currents flowing through the water in the GRP (glass reinforced plastic) inlet pipes caused by the electromagnetic interference from the huge pumps. Magmeters require a stable magnetic field without outside interference for operation. GRP pipes cannot easily be earthed which led to electromagnetic interference of water in the pipework. Using steel pipes in the process was not an option due to corrosion by the salt water. The Endress + Hauser Australia’s team then installed massive, steel earth rings between the flanges to provide solid grounding for eliminating the electromagnetic interference.
There was another issue that emerged at the initial stage. The contractors opted to do the commissioning and troubleshooting of the instruments using a proprietary software technology. This methodology did not work well since the device drivers did not incorporate all of the instrument vendor functionality and fine tuning of devices had also been a problem. Endress + Hauser Australia had proposed the usage of the open FDT/DTM technology embedded in their Fieldcare commissioning and troubleshooting software management tool.
The contractors reversed their decision and switched over to Endress + Hauser Australia’s Fieldcare that ran from a workstation. This strategy also enabled smoother commissioning, troubleshooting and start-up. The operators subsequently incorporated Endress + Hauser Australia’s Web-base Asset Management technology to manage all of their instrument assets.