With its tried-and-tested heat transfer fluid Diphyl, specialty chemicals company LANXESS is contributing to the cost-effective and environmentally friendly conversion of sunlight into electrical energy.

In the “Arenales” parabolic trough power plant near the city of Morón de la Frontera in Andalusia, Spain, parabolic mirrors concentrate solar radiation onto an absorber pipe, in which approximately 2,200 metric tons of Diphyl are circulating as a heat transfer fluid. With this heated medium and a heat exchanger, steam can be produced, which then as in a conventional power plant generates electricity using a steam turbine. A thermal salt storage facility means that electricity can still be generated after the sunset in summer months almost round the clock.

With an output of 50 MW, Arenales went on stream at the end of 2013 after a construction time of two years. It supplies around 50,000 Spanish households with environmentally friendly electricity. The building contractor was Ecolaire España, a subsidiary of the Spanish construction company OHL (Obrascón Huarte Lain) headquartered in Madrid.

Diphyl supports the sustainable use of solar energy
Unlike photovoltaic systems, solar-thermal collectors (CSP Concentrating Solar Power) such as Arenales do not utilize the photo effect, but instead make use of heat generation. There are many different variations of this, such as solar tower power plants, dish/Stirling units and updraft towers, but, because of their economic efficiency, the most frequently used technology is the parabolic trough system. Around 90 percent of all operators of CSP power plants use this process.

In a parabolic trough power plant, giant mirrors are joined together to form a trough-like collector, concentrating the solar energy on a focal line. Many parallel rows of collectors are linked together to form what is called a solar collector array. In fact, the mirrors concentrate the direct solar radiation to such an extent that a suitable operating medium such as Diphyl can be heated to temperatures of around 400 °C. With the resultant high-temperature heat, electricity is then generated in heat engines using steam turbines.

When things get really hot, Diphyl synthetic organic heat transfer fluid from LANXESS (diphyl.com) offers many advantages. It is still unsurpassed in terms of its heat stability and service life. Diphyl can be used economically at temperatures of up to 400 °C, retaining its heat transfer properties at a virtually constant level over thousands of hours of operation. In contrast to mineral-based fluids, Diphyl can also be used in the vapor phase because of its exact boiling point. It is virtually free of undesirable impurities such as chlorine and sulfur, which, even in small quantities, can lead to deposits and corrosion damage.

Because of their outstanding properties, Diphyl heat transfer fluids are used worldwide in more than 60 different applications.

LANXESS is a leading specialty chemicals company with sales of EUR 8.3 billion in 2013 and roughly 17,300 employees in 31 countries. The company is currently represented at 52 production sites worldwide. The core business of LANXESS is the development, manufacturing and marketing of plastics, rubber, intermediates and specialty chemicals. LANXESS is a member of the leading sustainability indices Dow Jones Sustainability Index (DJSI World and DJSI Europe) and FTSE4Good as well as CDP’s Climate Disclosure Leadership Index (CDLI).