Sarah Kellett explains how advanced valve control supports the world’s largest concentrated solar power plant

Rotork works closely with the solar energy industry to integrate economical and efficient intelligent valve actuation and control solutions into the design of concentrated solar power (CSP) plants.

The giant Noor CSP in Morocco is one of the projects using the Rotork solution.

The Noor I CSP Farm is the first phase of a project for the Moroccan Agency for Solar Energy (MASEN) to bring renewable energy to millions living in Morocco.

It is being followed by Noor ll and Noor lll expansions, due for completion by 2018, by when the entire grid will cover 6,000 acres and will be capable of generating up to 580MW of power, making it the largest CSP complex in the world.

Mirrors concentrate sunlight 

The now completed Noor l is made up of 500,000 curved mirrors, each standing at about 12m tall.

These mirrors concentrate the sun’s light onto a pipeline filled with heat transfer fluid (HTF), heating it up to 393°C. The HTF, comprising molten salt and oil, is stored and used to create superheated steam for driving turbines that generate electricity.

Construction of Noor ll, which will add 200MW generating capacity, is now underway.

To date, more than 500 Rotork electric and pneumatic valve actuators have been supplied on the Noor project.

The majority of these are the latest IQ multi-turn and IQTF full-turn non-intrusive intelligent electric actuators operating isolating and regulating valves on the HTF pipework and storage plant, monitored and controlled by Rotork Pakscan two-wire digital networks.

Economical and reliable valve control is enhanced by the extremely long-range network capabilities, built-in redundancy and installed cost savings enabled by Rotork Pakscan.

Each Pakscan Master Station can operate a bus loop of up to 20km in length with no deterioration in communication performance or the need for repeaters, making it ideal for the very spacious environment of a solar power plant.

Pakscan provides dual host communication paths as standard with the ability to isolate any field-based fault without interrupting communication with other units on the loop.

The configuration provides built-in redundancy in every area – from the valve to the control room.

In addition to the electric actuators, large numbers of Rotork GP and CP range pneumatic actuators have been supplied on butterfly valves providing isolating and regulating duties on the HTF and molten salt pipelines.

These scotch yoke actuators  are designed to provide part-turn movement for isolating or modulating duties.

The compact and efficient modular design is common to both ranges, yielding high torques even at low pressures.

The design concepts found in the large GP actuators have been applied to the CP range, bringing heavy-duty actuatorqualitiestosmall,quarter-turnactuators.

Sarah Kellett is with Rotork.