Rotork achieves 'one stop' solution to 'two shifting' problem

Rotork provides a complete 'one stop shop' package of new actuators and control valves, together with associated power and control systems, for the Powergen Ratcliffe power station.

A complete 'one stop shop' package contract, involving the installation of new Rotork actuators and control valves, together with associated power and control systems, has been successfully completed at the Powergen Ratcliffe power station. The multi-disciplined contract was awarded to Rotork company Exeeco by main contractor ALSTOM Power Ltd, Performance Projects Derby, as a major part of the work involved in upgrading the station to 'two shift' operation.

'Two shift' operation, which is required to meet the demands of the National Grid, requires that the station is able to come on and off load each day. This continuous process creates large temperature fluctuations, causing huge stresses in the boiler equipment, which are overcome by the installation of a pumping system that continues to circulate heated water around the boiler during the off load periods. The complex new plant known as the economiser re-circulation system needs to detect the temperature of the re-circulating water and control the flow to keep a constant temperature throughout the boiler tubes. Accuracy, fast response to temperature changes, high pressures and high flow rates are all important factors to be considered by the system designers. Rotork IQM and Skilmatic quarter-turn and linear electric actuators were incorporated into the system design due to their ability to modulate continuously as the temperature changes occur. In addition IQ25 and IQ12 actuators were installed on the system's isolating and bypass valves.

Exeeco was awarded the actuator control contract as a complete package, encompassing the design, manufacture, procurement and installation of all power and control cabling, marshalling boxes, power distribution equipment, linear control valves, quarter-turn ball control valves and actuators in accordance with the demanding control philosophy dictated by the customer.

The 'one stop shop' contract provided a total solution for the project, ensuring that the completed system meets the desired specification, whilst simplifying contractual complexities for all the involved companies.