Rotork Actuators For Sewage-Treatment Plant

Profibus network-enabled Rotork IQT intelligent electric actuators have been installed to operate butterfly and plug valves on new pipework at a sewage membrane treatment plant. The upgrade involves increasing the number of membrane packs in each tank to 36, increasing the treatment capacity without exceeding the confines of the existing works' footprint. Automation of the treatment process also enables it to run with increased efficiency and reduced energy consumption.

On each of the membrane plants, the Rotork IQT actuators operate inlet isolation and outlet modulating valves for the sewage, together with air, sodium hypochlorite and wash water-injection valves. Additional IQT actuators control the permeate isolation valves used for automated sequential flushing to maintain membrane efficiency. In total, 51 actuators are installed on each tank to provide automatic sequencing of the sewage treatment, membrane cleaning and backwashing processes. 14 Profibus-DP two-wire networks link the actuators to PLCs in the site's central MCC. These are controlled by a PLC and SCADA system written by Wessex Water's automation team.

The control PLC is a twin CPU configuration, with one dedicated to the control and monitoring of more than 300 actuators, while the other runs the automation process, resulting in the collection of control, status and full diagnostic data from each actuator, without any PLC speed or memory limitations. Diagnostic information is available, locally at the valve or nearby HMI, on the site SCADA system and at the regional operation centre at Bath. Running costs are expected to reduce due to more effective control of the plant.

DTEC Applies Vclad To Chemical-Plant Process Tower

DTEC has completed a multi-column turnkey project at a chemical plant located on the east coast of the UK. The project focus was on the refurbishment of a stainless-steel process tower with a diameter of approximately three metres, which required a corrosion-resistant weld overlay CrNiMo-3 (Alloy 625) onto a stainless-steel base material. DTEC achieved this without incident, using Vclad Weld Overlay technology.

Vclad combines digitally controlled synergic welding technology with multi-directional programmable automation. The result is a high quality and productive weld-overlay process that can be applied to many repair and upgrade scenarios, ranging from replacement of original equipment design materials through to the application of corrosion-resistant alloys.

Weld procedures are qualified to both ASME and EN standards, and because DTEC holds a library of typical PQRs, it can react to unknown scopes often found during routine turnaround inspections. Due to the flexibility of the Vclad equipment, DTEC can work around many vessel internal restrictions, such as beam stools and tray-support rings. The consistency gained using an automated welding process ensures that a code-consistent weld chemistry is achieved while ensuring a highly productive weld overlay deposition is delivered.

DTEC is an all-encompassing column specialist that services the chemical and oil-refining industries. Its products and services cater for multiple and single-column events offering both mechanical services as well as equipment manufacture for emergency supply and equipment change outs, providing in-situ column or vessel refurbishment or material upgrades using its Vclad weld-overlay capability.

In this project, the workscope included: column isolations, opening external and internal manways for inspection, tray removal, removal and replacement of internal tower attachments, automated weld overlay, reinstallation of trays, close-column manways and de-isolations.

Smart Wireless Monitors Temperatures In Plant

Emerson's Smart Wireless network using the Wirelesshart communications standard is contributing to process improvements at the Calgon Carbon plant in Blue Lake, California. The network provides continuous temperature measurements from a rotating catalyst kiln, where spent carbon particles are reactivated. Six Rosemount wireless temperature transmitters were installed to monitor temperatures in the kiln and transmit a steady stream of data, giving operators more information for controlling heat levels in each zone.

The wireless transmitters mounted on raised platforms on the surface of the kiln were connected to the existing thermocouples and the Wirelesshart self-organising mesh network was set up with a single Smart Wireless gateway. The six transmitters monitor temperatures in five zones of the kiln and at the outlet, communicating data reliably from the rotating kiln to the gateway, which then integrates the measurements in a host PLC.

Emerson offers a range of wireless field-instrumentation and plant-operations equipment, including Fisher position monitors, Rosemount Analytical and Machinery Health Management devices, and native wireless interfaces to AMS Suite predictive maintenance software, DeltaV digital-automation systems and Smartstart services.

Nexans To Supply Cable Link For Desalination Plant

Nexans is to supply a high-voltage underground cable link that will power an Australian seawater desalination plant, which is currently under construction in the state of Victoria. The contract covers the supply of around 260km of 220kV XLPE cable, made and tested as a 275kV cable, to Thiess Degremont, which is contracted to design and construct the EUR2.2bn (GBP2bn) Victorian Desalination Project to deliver up to 150 billion litres of water a year to Melbourne and regional communities.

The Victorian Desalination Project includes an 84km underground pipeline to connect the reverse-osmosis plant to a transfer main and then back to the reservoir. The electric power required by the new plant will be supplied by the 87km-long underground cables co-located with the pipeline, creating the world's longest high-voltage AC underground link operating at this power level.

An underground link was the preferred option for the project since it is both more energy efficient and secure than overhead lines and will also have the least impact on landowners, farmers and other people living and working in the area. Olex, a Nexans company serving the Australian and Asia-Pacific markets, will produce 225km of the underground cable locally at its Tottenham facility in Victoria.

It will be manufactured on equipment recently installed as part of a EUR12.5m upgrade that now enables Tottenham to produce XLPE (cross-linked polyethylene) cables up to 500kV. The remaining length of cable will be supplied by the Nexans factory located in Charleroi, Belgium. The cable will be supplied progressively throughout 2010.

Emerson To Update Power-Plant Instrumentation

Emerson Process Management has been awarded a contract to update the instrumentation and controls on units 5 and 6 of the lignite-fired Belchatow Power Plant in Poland. The project will see Emerson serving as the main automation contractor, responsible for modernising the instrumentation, control and electrical subsystems.

Emerson will perform engineering and management services that include the installation of its Plantweb digital plant architecture with the Ovation expert control system. Using open Wirelesshart products, Emerson's Smart Wireless network will connect over 110 Rosemount wireless temperature transmitters that will monitor boiler temperatures on each unit. The complete retrofit project will enable the units to reach 320,000 hours of operation.

The project will contribute to emissions reductions from the two units, with CO2 and NOx both falling below 200mg/m3. Emerson will design, install and commission the digital automation system and perform various services on the units' electrical subsystems, such as the generator, transformers, feeder ducts and switchgear.

Emerson's Ovation system will monitor and control each unit's boiler and balance of plant processes and equipment, as well as the 0.4 and 6kV electrical switchgear and unit power output. In addition, it will interface with each unit's turbine control and thermal-protection systems. The Ovation system will oversee automatic boiler/unit start-up/shutdown and automatic unit operation within the full range of load changes.